[Federal Register Volume 74, Number 239 (Tuesday, December 15, 2009)]
[Rules and Regulations]
[Pages 66496-66546]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E9-29537]
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Part V
Environmental Protection Agency
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40 CFR Chapter I
Endangerment and Cause or Contribute Findings for Greenhouse Gases
Under Section 202(a) of the Clean Air Act; Final Rule
Federal Register / Vol. 74, No. 239 / Tuesday, December 15, 2009 /
Rules and Regulations
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Chapter I
[EPA-HQ-OAR-2009-0171; FRL-9091-8]
RIN 2060-ZA14
Endangerment and Cause or Contribute Findings for Greenhouse
Gases Under Section 202(a) of the Clean Air Act
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
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SUMMARY: The Administrator finds that six greenhouse gases taken in
combination endanger both the public health and the public welfare of
current and future generations. The Administrator also finds that the
combined emissions of these greenhouse gases from new motor vehicles
and new motor vehicle engines contribute to the greenhouse gas air
pollution that endangers public health and welfare under CAA section
202(a). These Findings are based on careful consideration of the full
weight of scientific evidence and a thorough review of numerous public
comments received on the Proposed Findings published April 24, 2009.
DATES: These Findings are effective on January 14, 2010.
ADDRESSES: EPA has established a docket for this action under Docket ID
No. EPA-HQ-OAR-2009-0171. All documents in the docket are listed on the
www.regulations.gov Web site. Although listed in the index, some
information is not publicly available, e.g., confidential business
information (CBI) or other information whose disclosure is restricted
by statute. Certain other material, such as copyrighted material, is
not placed on the Internet and will be publicly available only in hard
copy form. Publicly available docket materials are available either
electronically through www.regulations.gov or in hard copy at EPA's
Docket Center, Public Reading Room, EPA West Building, Room 3334, 1301
Constitution Avenue, NW., Washington, DC 20004. This Docket Facility is
open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding
legal holidays. The telephone number for the Public Reading Room is
(202) 566-1744, and the telephone number for the Air Docket is (202)
566-1742.
FOR FURTHER INFORMATION CONTACT: Jeremy Martinich, Climate Change
Division, Office of Atmospheric Programs (MC-6207J), Environmental
Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460;
telephone number: (202) 343-9927; fax number: (202) 343-2202; e-mail
address: [email protected]. For additional information regarding
these Findings, please go to the Web site http://www.epa.gov/climatechange/endangerment.html.
SUPPLEMENTARY INFORMATION:
Judicial Review
Under CAA section 307(b)(1), judicial review of this final action
is available only by filing a petition for review in the U.S. Court of
Appeals for the District of Columbia Circuit by February 16, 2010.
Under CAA section 307(d)(7)(B), only an objection to this final action
that was raised with reasonable specificity during the period for
public comment can be raised during judicial review. This section also
provides a mechanism for us to convene a proceeding for
reconsideration, `` `[i]f the person raising an objection can
demonstrate to EPA that it was impracticable to raise such objection
within [the period for public comment] or if the grounds for such
objection arose after the period for public comment (but within the
time specified for judicial review) and if such objection is of central
relevance to the outcome of this rule.' '' Any person seeking to make
such a demonstration to us should submit a Petition for Reconsideration
to the Office of the Administrator, Environmental Protection Agency,
Room 3000, Ariel Rios Building, 1200 Pennsylvania Ave., NW.,
Washington, DC 20004, with a copy to the person listed in the preceding
FOR FURTHER INFORMATION CONTACT section, and the Associate General
Counsel for the Air and Radiation Law Office, Office of General Counsel
(Mail Code 2344A), Environmental Protection Agency, 1200 Pennsylvania
Ave., NW., Washington, DC 20004.
Acronyms and Abbreviations. The following acronyms and
abbreviations are used in this document.
ACUS Administrative Conference of the United States
ANPR Advance Notice of Proposed Rulemaking
APA Administrative Procedure Act
CAA Clean Air Act
CAFE Corporate Average Fuel Economy
CAIT Climate Analysis Indicators Tool
CASAC Clean Air Scientific Advisory Committee
CBI Confidential Business Information
CCSP Climate Change Science Program
CFCs chlorofluorocarbons
CFR Code of Federal Regulations
CH4 methane
CO2 carbon dioxide
CO2e CO2-equivalent
CRU Climate Research Unit
DOT U.S. Department of Transportation
EO Executive Order
EPA U.S. Environmental Protection Agency
FR Federal Register
GHG greenhouse gas
GWP global warming potential
HadCRUT Hadley Centre/Climate Research Unit (CRU) temperature record
HCFCs hydrochlorofluorocarbons
HFCs hydrofluorocarbons
IA Interim Assessment report
IPCC Intergovernmental Panel on Climate Change
MPG miles per gallon
MWP Medieval Warm Period
N2O nitrous oxide
NAAQS National Ambient Air Quality Standards
NAICS North American Industry Classification System
NASA National Aeronautics and Space Administration
NF3 nitrogen trifluoride
NHTSA National Highway Traffic Safety Administration
NOAA National Oceanic and Atmospheric Administration
NOI Notice of Intent
NOX nitrogen oxides
NRC National Research Council
NSPS new source performance standards
NTTAA National Technology Transfer and Advancement Act of 1995
OMB Office of Management and Budget
PFCs perfluorocarbons
PM particulate matter
PSD Prevention of Significant Deterioration
RFA Regulatory Flexibility Act
SF6 sulfur hexafluoride
SIP State Implementation Plan
TSD technical support document
U.S. United States
UMRA Unfunded Mandates Reform Act of 1995
UNFCCC United Nations Framework Convention on Climate Change
USGCRP U.S. Global Climate Research Program
VOC volatile organic compound(s)
WCI Western Climate Initiative
WRI World Resources Institute
TABLE OF CONTENTS
I. Introduction
A. Overview
B. Background Information Helpful To Understand These Findings
1. Greenhouse Gases and Transportation Sources Under CAA Section
202(a)
2. Joint EPA and Department of Transportation Proposed
Greenhouse Gas Rule
C. Public Involvement
1. EPA's Initial Work on Endangerment
2. Public Involvement Since the April 2009 Proposed Endangerment
Finding
3. Issues Raised Regarding the Rulemaking Process
II. Legal Framework for This Action
A. Section 202(a) of the CAA--Endangerment and Cause or
Contribute
1. The Statutory Framework
2. Summary of Response to Key Legal Comments on the
Interpretation of the CAA Section 202(a) Endangerment and Cause or
Contribute Test
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B. Air Pollutant, Public Health and Welfare
III. EPA's Approach for Evaluating the Evidence Before It
A. The Science on Which the Decisions Are Based
B. The Law on Which the Decisions Are Based
C. Adaptation and Mitigation
D. Geographic Scope of Impacts
E. Temporal Scope of Impacts
F. Impacts of Potential Future Regulations and Processes that
Generate Greenhouse Gas Emissions
IV. The Administrator's Finding That Emissions of Greenhouse Gases
Endanger Public Health and Welfare
A. The Air Pollution Consists of Six Key Greenhouse Gases
1. Common Physical Properties of the Six Greenhouse Gases
2. Evidence That the Six Greenhouse Gases Are the Primary Driver
of Current and Projected Climate Change
3. The Six Greenhouse Gases Are Currently the Common Focus of
the Climate Change Science and Policy Communities
4. Defining Air Pollution as the Aggregate Group of Six
Greenhouse Gases Is Consistent With Evaluation of Risks and Impacts
Due to Human-Induced Climate Change
5. Defining the Air Pollution as the Aggregate Group of Six
Greenhouse Gases Is Consistent With Past EPA Practice
6. Other Climate Forcers Not Being Included in the Definition of
Air Pollution for This Finding
7. Summary of Key Comments on Definition of Air Pollution
B. The Air Pollution Is Reasonably Anticipated To Endanger Both
Public Health and Welfare
1. The Air Pollution Is Reasonably Anticipated To Endanger
Public Health
2. The Air Pollution Is Reasonably Anticipated To Endanger
Public Welfare
V. The Administrator's Finding That Greenhouse Gases From CAA
Section 202(a) Sources Cause or Contribute to the Endangerment of
Public Health and Welfare
A. The Administrator's Definition of the ``Air Pollutant''
B. The Administrator's Finding Whether Emissions of the Air
Pollutant From Section 202(a) Source Categories Cause or Contribute
to the Air Pollution That May Be Reasonably Anticipated To Endanger
Public Health and Welfare
C. Response to Key Comments on the Administrator's Cause or
Contribute Finding
1. The Administrator Reasonably Defined the ``Air Pollutant''
for the Cause or Contribute Analysis
2. The Administrator's Cause or Contribute Analysis Was
Reasonable
VI. Statutory and Executive Reviews
A. Executive Order 12866: Regulatory Planning and Review
B. Paperwork Reduction Act
C. Regulatory Flexibility Act
D. Unfunded Mandates Reform Act
E. Executive Order 13132: Federalism
F. Executive Order 13175: Consultation and Coordination With
Indian Tribal Governments
G. Executive Order 13045: Protection of Children From
Environmental Health Risks and Safety Risks
H. Executive Order 13211: Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use
I. National Technology Transfer and Advancement Act
J. Executive Order 12898: Federal Actions To Address
Environmental Justice in Minority Populations and Low-Income
Populations
K. Congressional Review Act
I. Introduction
A. Overview
Pursuant to CAA section 202(a), the Administrator finds that
greenhouse gases in the atmosphere may reasonably be anticipated both
to endanger public health and to endanger public welfare. Specifically,
the Administrator is defining the ``air pollution'' referred to in CAA
section 202(a) to be the mix of six long-lived and directly-emitted
greenhouse gases: carbon dioxide (CO2), methane
(CH4), nitrous oxide (N2O), hydrofluorocarbons
(HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride
(SF6). In this document, these six greenhouse gases are
referred to as ``well-mixed greenhouse gases'' in this document (with
more precise meanings of ``long lived'' and ``well mixed'' provided in
Section IV.A).
The Administrator has determined that the body of scientific
evidence compellingly supports this finding. The major assessments by
the U.S. Global Climate Research Program (USGCRP), the
Intergovernmental Panel on Climate Change (IPCC), and the National
Research Council (NRC) serve as the primary scientific basis supporting
the Administrator's endangerment finding.\1\ The Administrator reached
her determination by considering both observed and projected effects of
greenhouse gases in the atmosphere, their effect on climate, and the
public health and welfare risks and impacts associated with such
climate change. The Administrator's assessment focused on public health
and public welfare impacts within the United States. She also examined
the evidence with respect to impacts in other world regions, and she
concluded that these impacts strengthen the case for endangerment to
public health and welfare because impacts in other world regions can in
turn adversely affect the United States.
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\1\ Section III of these Findings discusses the science on which
these Findings are based. In addition, the Technical Support
Document (TSD) accompanying these Findings summarizes the major
assessments from the USGCRP, IPCC, and NRC.
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The Administrator recognizes that human-induced climate change has
the potential to be far-reaching and multi-dimensional, and in light of
existing knowledge, that not all risks and potential impacts can be
quantified or characterized with uniform metrics. There is variety not
only in the nature and potential magnitude of risks and impacts, but
also in our ability to characterize, quantify and project such impacts
into the future. The Administrator is using her judgment, based on
existing science, to weigh the threat for each of the identifiable
risks, to weigh the potential benefits where relevant, and ultimately
to assess whether these risks and effects, when viewed in total,
endanger public health or welfare.
The Administrator has considered how elevated concentrations of the
well-mixed greenhouse gases and associated climate change affect public
health by evaluating the risks associated with changes in air quality,
increases in temperatures, changes in extreme weather events, increases
in food- and water-borne pathogens, and changes in aeroallergens. The
evidence concerning adverse air quality impacts provides strong and
clear support for an endangerment finding. Increases in ambient ozone
are expected to occur over broad areas of the country, and they are
expected to increase serious adverse health effects in large population
areas that are and may continue to be in nonattainment. The evaluation
of the potential risks associated with increases in ozone in attainment
areas also supports such a finding.
The impact on mortality and morbidity associated with increases in
average temperatures, which increase the likelihood of heat waves, also
provides support for a public health endangerment finding. There are
uncertainties over the net health impacts of a temperature increase due
to decreases in cold-related mortality, but some recent evidence
suggests that the net impact on mortality is more likely to be adverse,
in a context where heat is already the leading cause of weather-related
deaths in the United States.
The evidence concerning how human-induced climate change may alter
extreme weather events also clearly supports a finding of endangerment,
given the serious adverse impacts that can result from such events and
the increase in risk, even if small, of the occurrence and intensity of
events such as hurricanes and floods. Additionally, public health is
expected to be
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adversely affected by an increase in the severity of coastal storm
events due to rising sea levels.
There is some evidence that elevated carbon dioxide concentrations
and climate changes can lead to changes in aeroallergens that could
increase the potential for allergenic illnesses. The evidence on
pathogen borne disease vectors provides directional support for an
endangerment finding. The Administrator acknowledges the many
uncertainties in these areas. Although these adverse effects provide
some support for an endangerment finding, the Administrator is not
placing primary weight on these factors.
Finally, the Administrator places weight on the fact that certain
groups, including children, the elderly, and the poor, are most
vulnerable to these climate-related health effects.
The Administrator has considered how elevated concentrations of the
well-mixed greenhouse gases and associated climate change affect public
welfare by evaluating numerous and far-ranging risks to food production
and agriculture, forestry, water resources, sea level rise and coastal
areas, energy, infrastructure, and settlements, and ecosystems and
wildlife. For each of these sectors, the evidence provides support for
a finding of endangerment to public welfare. The evidence concerning
adverse impacts in the areas of water resources and sea level rise and
coastal areas provides the clearest and strongest support for an
endangerment finding, both for current and future generations. Strong
support is also found in the evidence concerning infrastructure and
settlements, as well ecosystems and wildlife. Across the sectors, the
potential serious adverse impacts of extreme events, such as wildfires,
flooding, drought, and extreme weather conditions, provide strong
support for such a finding.
Water resources across large areas of the country are at serious
risk from climate change, with effects on water supplies, water
quality, and adverse effects from extreme events such as floods and
droughts. Even areas of the country where an increase in water flow is
projected could face water resource problems from the supply and water
quality problems associated with temperature increases and
precipitation variability, as well as the increased risk of serious
adverse effects from extreme events, such as floods and drought. The
severity of risks and impacts is likely to increase over time with
accumulating greenhouse gas concentrations and associated temperature
increases and precipitation changes.
Overall, the evidence on risk of adverse impacts for coastal areas
provides clear support for a finding that greenhouse gas air pollution
endangers the welfare of current and future generations. The most
serious potential adverse effects are the increased risk of storm surge
and flooding in coastal areas from sea level rise and more intense
storms. Observed sea level rise is already increasing the risk of storm
surge and flooding in some coastal areas. The conclusion in the
assessment literature that there is the potential for hurricanes to
become more intense (and even some evidence that Atlantic hurricanes
have already become more intense) reinforces the judgment that coastal
communities are now endangered by human-induced climate change, and may
face substantially greater risk in the future. Even if there is a low
probability of raising the destructive power of hurricanes, this threat
is enough to support a finding that coastal communities are endangered
by greenhouse gas air pollution. In addition, coastal areas face other
adverse impacts from sea level rise such as land loss due to
inundation, erosion, wetland submergence, and habitat loss. The
increased risk associated with these adverse impacts also endangers
public welfare, with an increasing risk of greater adverse impacts in
the future.
Strong support for an endangerment finding is also found in the
evidence concerning energy, infrastructure, and settlements, as well
ecosystems and wildlife. While the impacts on net energy demand may be
viewed as generally neutral for purposes of making an endangerment
determination, climate change is expected to result in an increase in
electricity production, especially supply for peak demand. This may be
exacerbated by the potential for adverse impacts from climate change on
hydropower resources as well as the potential risk of serious adverse
effects on energy infrastructure from extreme events. Changes in
extreme weather events threaten energy, transportation, and water
resource infrastructure. Vulnerabilities of industry, infrastructure,
and settlements to climate change are generally greater in high-risk
locations, particularly coastal and riverine areas, and areas whose
economies are closely linked with climate-sensitive resources. Climate
change will likely interact with and possibly exacerbate ongoing
environmental change and environmental pressures in settlements,
particularly in Alaska where indigenous communities are facing major
environmental and cultural impacts on their historic lifestyles. Over
the 21st century, changes in climate will cause some species to shift
north and to higher elevations and fundamentally rearrange U.S.
ecosystems. Differential capacities for range shifts and constraints
from development, habitat fragmentation, invasive species, and broken
ecological connections will likely alter ecosystem structure, function,
and services, leading to predominantly negative consequences for
biodiversity and the provision of ecosystem goods and services.
There is a potential for a net benefit in the near term \2\ for
certain crops, but there is significant uncertainty about whether this
benefit will be achieved given the various potential adverse impacts of
climate change on crop yield, such as the increasing risk of extreme
weather events. Other aspects of this sector may be adversely affected
by climate change, including livestock management and irrigation
requirements, and there is a risk of adverse effect on a large segment
of the total crop market. For the near term, the concern over the
potential for adverse effects in certain parts of the agriculture
sector appears generally comparable to the potential for benefits for
certain crops. However, The body of evidence points towards increasing
risk of net adverse impacts on U.S. food production and agriculture
over time, with the potential for significant disruptions and crop
failure in the future.
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\2\ The temporal scope of impacts is discussed in more detail in
Section III.C. The phrase ``near term'' as used in this document
generally refers to the current time period from and the next few
decades. The phrase ``long term'' generally refers to a time frame
extending beyond that to approximately the middle to the end of this
century.
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For the near term, the Administrator finds the beneficial impact on
forest growth and productivity in certain parts of the country from
elevated carbon dioxide concentrations and temperature increases to
date is offset by the clear risk from the observed increases in
wildfires, combined with risks from the spread of destructive pests and
disease. For the longer term, the risk from adverse effects increases
over time, such that overall climate change presents serious adverse
risks for forest productivity. There is compelling reason to find that
the support for a positive endangerment finding increases as one
considers expected future conditions where temperatures continue to
rise.
Looking across all of the sectors discussed above, the evidence
provides compelling support for finding that greenhouse gas air
pollution endangers the public welfare of both current and
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future generations. The risk and the severity of adverse impacts on
public welfare are expected to increase over time.
The Administrator also finds that emissions of well-mixed
greenhouse gases from the transportation sources covered under CAA
section 202(a) \3\ contribute to the total greenhouse gas air
pollution, and thus to the climate change problem, which is reasonably
anticipated to endanger public health and welfare. The Administrator is
defining the air pollutant that contributes to climate change as the
aggregate group of the well-mixed greenhouse gases. The definition of
air pollutant used by the Administrator is based on the similar
attributes of these substances. These attributes include the fact that
they are sufficiently long-lived to be well mixed globally in the
atmosphere, that they are directly emitted, and that they exert a
climate warming effect by trapping outgoing, infrared heat that would
otherwise escape to space, and that they are the focus of climate
change science and policy.
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\3\ Section 202(a) source categories include passenger cars,
heavy-, medium and light-duty trucks, motorcycles, and buses.
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In order to determine if emissions of the well-mixed greenhouse
gases from CAA section 202(a) source categories contribute to the air
pollution that endangers public health and welfare, the Administrator
compared the emissions from these CAA section 202(a) source categories
to total global and total U.S. greenhouse gas emissions, finding that
these source categories are responsible for about 4 percent of total
global well-mixed greenhouse gas emissions and just over 23 percent of
total U.S. well-mixed greenhouse gas emissions. The Administrator found
that these comparisons, independently and together, clearly establish
that these emissions contribute to greenhouse gas concentrations. For
example, the emissions of well-mixed greenhouse gases from CAA section
202(a) sources are larger in magnitude than the total well-mixed
greenhouse gas emissions from every other individual nation with the
exception of China, Russia, and India, and are the second largest
emitter within the United States behind the electricity generating
sector. As the Supreme Court noted, ``[j]udged by any standard, U.S.
motor-vehicle emissions make a meaningful contribution to greenhouse
gas concentrations and hence, * * * to global warming.'' Massachusetts
v. EPA, 549 U.S. 497, 525 (2007).
The Administrator's findings are in response to the Supreme Court's
decision in Massachusetts v. EPA. That case involved a 1999 petition
submitted by the International Center for Technology Assessment and 18
other environmental and renewable energy industry organizations
requesting that EPA issue standards under CAA section 202(a) for the
emissions of carbon dioxide, methane, nitrous oxide, and
hydrofluorocarbons from new motor vehicles and engines. The
Administrator's findings are in response to this petition and are for
purposes of CAA section 202(a).
B. Background Information Helpful To Understand These Findings
This section provides some basic information regarding greenhouse
gases and the CAA section 202(a) source categories, as well as the
ongoing joint-rulemaking on greenhouse gases by EPA and the Department
of Transportation. Additional technical and legal background, including
a summary of the Supreme Court's Massachusetts v. EPA decision, can be
found in the Proposed Endangerment and Contribution Findings (74 FR
18886, April 24, 2009).
1. Greenhouse Gases and Transportation Sources Under CAA Section 202(a)
Greenhouse gases are naturally present in the atmosphere and are
also emitted by human activities. Greenhouse gases trap the Earth's
heat that would otherwise escape from the atmosphere, and thus form the
greenhouse effect that helps keep the Earth warm enough for life. Human
activities are intensifying the naturally-occurring greenhouse effect
by adding greenhouse gases to the atmosphere. The primary greenhouse
gases of concern that are directly emitted by human activities include
carbon dioxide, methane, nitrous oxide, hydrofluorocarbons,
perfluorocarbons, and sulfur hexafluoride. Other pollutants (such as
aerosols) and other human activities, such as land use changes that
alter the reflectivity of the Earth's surface, also cause climatic
warming and cooling effects. In these Findings, the term ``climate
change'' generally refers to the global warming effect plus other
associated changes (e.g., precipitation effects, sea level rise,
changes in the frequency and severity of extreme weather events) being
induced by human activities, including activities that emit greenhouse
gases. Natural causes also, contribute to climate change and climatic
changes have occurred throughout the Earth's history. The concern now,
however, is that the changes taking place in our atmosphere as a result
of the well-documented buildup of greenhouse gases due to human
activities are changing the climate at a pace and in a way that
threatens human health, society, and the natural environment. Further
detail on the state of climate change science can be found in Section
III of these Findings as well as the technical support document (TSD)
that accompanies this action (www.epa.gov/climatechange/endangerment.html).
The transportation sector is a major source of greenhouse gas
emissions both in the United States and in the rest of the world. The
transportation sources covered under CAA section 202(a)--the section of
the CAA under which these Findings occur--include passenger cars,
light- and heavy-duty trucks, buses, and motorcycles. These
transportation sources emit four key greenhouse gases: carbon dioxide,
methane, nitrous oxide, and hydrofluorocarbons. Together, these
transportation sources are responsible for 23 percent of total annual
U.S. greenhouse gas emissions, making this source the second largest in
the United States behind electricity generation.\4\
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\4\ The units for greenhouse gas emissions in these findings are
provided in carbon dioxide equivalent units, where carbon dioxide is
the reference gas and every other greenhouse gas is converted to its
carbon dioxide equivalent by using the 100-year global warming
potential (as estimated by the Intergovernmental Panel on Climate
Change (IPCC). assigned to each gas. The reference gas used is
CO2, and therefore Global Warming Potential (GWP)-
weighted emissions are measured in teragrams of CO2
equivalent (Tg CO2 eq.). In accordance with UNFCCC
reporting procedures, the United States quantifies greenhouse gas
emissions using the 100-year time frame values for GWPs established
in the IPCC Second Assessment Report.
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Further discussion of the emissions data supporting the
Administrator's cause or contribute finding can be found in Section V
of these Findings, and the detailed greenhouse gas emissions data for
section 202(a) source categories can be found in Appendix B of EPA's
TSD.
2. Joint EPA and Department of Transportation Proposed Greenhouse Gas
Rule
On September 15, 2009, EPA and the Department of Transportation's
National Highway Safety Administration (NHTSA) proposed a National
Program that would dramatically reduce greenhouse gas emissions and
improve fuel economy for new cars and trucks sold in the United States.
The combined EPA and NHTSA standards that make up this proposed
National Program would apply to passenger cars, light-duty trucks, and
medium-duty passenger vehicles, covering model years 2012 through 2016.
They proposed to require these vehicles to meet an estimated combined
average
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emissions level of 250 grams of carbon dioxide per mile, equivalent to
35.5 miles per gallon (MPG) if the automobile industry were to meet
this carbon dioxide level solely through fuel economy improvements.
Together, these proposed standards would cut carbon dioxide emissions
by an estimated 950 million metric tons and 1.8 billion barrels of oil
over the lifetime of the vehicles sold under the program (model years
2012-2016). The proposed rulemaking can be viewed at (74 FR 49454,
September 28, 2009).
C. Public Involvement
In response to the Supreme Court's decision, EPA has been examining
the scientific and technical basis for the endangerment and cause or
contribute decisions under CAA section 202(a) since 2007. The science
informing the decision-making process has grown stronger since our work
began. EPA's approach to evaluating the science, including comments
submitted during the public comment period, is further discussed in
Section III.A of these Findings. Public review and comment has always
been a major component of EPA's process.
1. EPA's Initial Work on Endangerment
As part of the Advance Notice of Proposed Rulemaking: Regulating
Greenhouse Gas Emissions under the Clean Air Act (73 FR 44353)
published in July 2008, EPA provided a thorough discussion of the
issues and options pertaining to endangerment and cause or contribute
findings under the CAA. The Agency also issued a TSD providing an
overview of all the major scientific assessments available at the time
and emission inventory data relevant to the contribution finding
(Docket ID No. EPA-HQ-OAR-2008-0318). The comment period for that
Advance Notice was 120 days, and it provided an opportunity for EPA to
hear from the public with regard to the issues involved in endangerment
and cause or contribute findings as well as the supporting science. EPA
received, reviewed and considered numerous comments at that time and
this public input was reflected in the Findings that the Administrator
proposed in April 2009. In addition, many comments were received on the
TSD released with the Advance Notice and reflected in revisions to the
TSD released in April 2009 to accompany the Administrator's proposal.
All public comments on the Advance Notice are contained in the public
docket for this action (Docket ID No. EPA-HQ-OAR-2008-0318) accessible
through www.regulations.gov.
2. Public Involvement Since the April 2009 Proposed Endangerment
Finding
The Proposed Endangerment and Cause or Contribute Findings for
Greenhouse Gases (Proposed Findings) was published on April 24, 2009
(74 FR 18886). The Administrator's proposal was subject to a 60-day
public comment period, which ended June 23, 2009, and also included two
public hearings. Over 380,000 public comments were received on the
Administrator's proposed endangerment and cause or contribute findings,
including comments on the elements of the Administrator's April 2009
proposal, the legal issues pertaining to the Administrator's decisions,
and the underlying TSD containing the scientific and technical
information.
A majority of the comments (approximately 370,000) were the result
of mass mail campaigns, which are defined as groups of comments that
are identical or very similar in form and content. Overall, about two-
thirds of the mass-mail comments received are supportive of the
Findings and generally encouraged the Administrator both to make a
positive endangerment determination and implement greenhouse gas
emission regulations. Of the mass mail campaigns in disagreement with
the Proposed Findings most either oppose the proposal on economic
grounds (e.g., due to concern for regulatory measures following an
endangerment finding) or take issue with the proposed finding that
atmospheric greenhouse gas concentrations endanger public health and
welfare. Please note that for mass mailer campaigns, a representative
copy of the comment is posted in the public docket for this Action
(Docket ID No. EPA-HQ-OAR-2009-0171) at www.regulations.gov.
Approximately 11,000 other public comments were received. These
comments raised a variety of issues related to the scientific and
technical information EPA relied upon in making the Proposed Findings,
legal and procedural issues, the content of the Proposed Findings, and
the implications of the Proposed Findings.
In light of the very large number of comments received and the
significant overlap between many comments, EPA has not responded to
each comment individually. Rather, EPA has summarized and provided
responses to each significant argument, assertion and question
contained within the totality of the comments. EPA's responses to some
of the most significant comments are provided in these Findings.
Responses to all significant issues raised by the comments are
contained in the 11 volumes of the Response to Comments document,
organized by subject area (found in docket EPA-HQ-OAR-2009-0171).
3. Issues Raised Regarding the Rulemaking Process
EPA received numerous comments on process-related issues, including
comments urging the Administrator to delay issuing the final findings,
arguing that it was improper for the Administrator to sever the
endangerment and cause or contribute findings from the attendant
section 202(a) standards, arguing the final decision was preordained by
the President's May vehicle announcement, and questioning the adequacy
of the comment period. Summaries of key comments and EPA's responses
are discussed in this section. Additional and more detailed responses
can be found in the Response to Comments document, Volume 11. As noted
in the Response to Comments document, EPA also received comments
supporting the overall process.
a. It Is Reasonable for the Administrator To Issue the Endangerment and
Cause or Contribute Findings Now
Though the Supreme Court did not establish a specific deadline for
EPA to act, more than two and a half years have passed since the remand
from the Supreme Court, and it has been 10 years since EPA received the
original petition requesting that EPA regulate greenhouse gas emissions
from new motor vehicles. EPA has a responsibility to respond to the
Supreme Court's decision and to fulfill its obligations under current
law, and there is good reason to act now given the urgency of the
threat of climate change and the compelling scientific evidence.
Many commenters urge EPA to delay making final findings for a
variety of reasons. They note that the Supreme Court did not establish
a deadline for EPA to act on remand. Commenters also argue that the
Supreme Court's decision does not require that EPA make a final
endangerment finding, and thus that EPA has discretionary power and may
decline to issue an endangerment finding, not only if the science is
too uncertain, but also if EPA can provide ``some reasonable
explanation'' for exercising its discretion. These commenters interpret
the Supreme Court decision not as rejecting all policy reasons for
declining to undertake an endangerment finding, but rather as
dismissing solely the policy reasons EPA set forth in 2003. Some
commenters cite language in the
[[Page 66501]]
Supreme Court decision regarding EPA's discretion regarding ``the
manner, timing, content, and coordination of its regulations,'' and the
Court's declining to rule on ``whether policy concerns can inform
EPA\'\s actions in the event that it makes'' a CAA section 202(a)
finding to support their position.
Commenters then suggest a variety of policy reasons that EPA can
and should make to support a decision not to undertake a finding of
endangerment under CAA section 202(a)(1). For example, they argue that
a finding of endangerment would trigger several other regulatory
programs--such as the Prevention of Significant Deterioration (PSD)
provisions--that would impose an unreasonable burden on the economy and
government, without providing a benefit to the environment. Some
commenters contend that EPA should defer issuing a final endangerment
finding while Congress considers legislation. Many commenters note the
ongoing international discussions regarding climate change and state
their belief that unilateral EPA action would interfere with those
negotiations. Others suggest deferring the EPA portion of the joint
U.S. Department of Transportation (DOT)/EPA rulemaking because they
argue that the new Corporate Average Fuel Economy (CAFE) standards will
effectively result in lower greenhouse gas emissions from new motor
vehicles, while avoiding the inevitable problems and concerns of
regulating greenhouse gases under the CAA.
Other commenters argue that the endangerment determination has to
be made on the basis of scientific considerations only. These
commenters state that the Court was clear that ``[t]he statutory
question is whether sufficient information exists to make an
endangerment finding,'' and thus, only if ``the scientific uncertainty
is so profound that it precludes EPA from making a reasoned judgment as
to whether greenhouse gases contribute to global warming,'' may EPA
avoid making a positive or negative endangerment finding. Many
commenters urge EPA to take action quickly. They note that it has been
10 years since the original petition requesting that EPA regulate
greenhouse gas emissions from motor vehicles was submitted to EPA. They
argue that climate change is a serious problem that requires immediate
action.
EPA agrees with the commenters who argue that the Supreme Court
decision held that EPA is limited to consideration of science when
undertaking an endangerment finding, and that we cannot delay issuing a
finding due to policy concerns if the science is sufficiently certain
(as it is here). The Supreme Court stated that ``EPA can avoid taking
further action only if it determines that greenhouse gases do not
contribute to climate change or if it provides some reasonable
explanation as to why it cannot or will not exercise its discretion to
determine whether they do'' 549 U.S. at 533. Some commenters point to
this last provision, arguing that the policy reasons they provide are a
``reasonable explanation'' for not moving forward at this time.
However, this ignores other language in the decision that clearly
indicates that the Court interprets the statute to allow for the
consideration only of science. For example, in rejecting the policy
concerns expressed by EPA in its 2003 denial of the rulemaking
petition, the Court noted that ``it is evident [the policy
considerations] have nothing to do with whether greenhouse gas
emissions contribute to climate change. Still less do they amount to a
reasoned justification for declining to form a scientific judgment''
Id. at 533-34 (emphasis added).
Moreover, the Court also held that ``[t]he statutory question is
whether sufficient information exists to make an endangerment finding''
Id. at 534. Taken as a whole, the Supreme Court's decision clearly
indicates that policy reasons do not justify the Administrator avoiding
taking further action on the question here.
We also note that the language many commenters quoted from the
Supreme Court decision about EPA's discretion regarding the manner,
timing and content of Agency actions, and the ability to consider
policy concerns, relate to the motor vehicle standards required in the
event that EPA makes a positive endangerment finding, and not the
finding itself. EPA has long taken the position that it does have such
discretion in the standard-setting step under CAA section 202(a).
b. The Administrator Reasonably Proceeded With the Endangerment and
Cause or Contribute Findings Separate From the CAA Section 202(a)
Standard Rulemaking
As discussed in the Proposed Findings, typically endangerment and
cause or contribute findings have been proposed concurrently with
proposed standards under various sections of the CAA, including CAA
section 202(a). EPA received numerous comments on its decision to
propose the endangerment and cause or contribute findings separate from
any standards under CAA section 202(a).
Commenters argue that EPA has no authority to issue an endangerment
determination under CAA section 202(a) separate and apart from the
rulemaking to establish emissions standards under CAA section 202(a).
According to these commenters, CAA section 202(a) provides only one
reason to issue an endangerment determination, and that is as the basis
for promulgating emissions standards for new motor vehicles; thus, it
does not authorize such a stand-alone endangerment finding, and EPA may
not create its own procedural rules completely divorced from the
statutory text. They continue by stating that while CAA section 202(a)
says EPA may issue emissions standards conditioned on such a finding,
it does not say EPA may first issue an endangerment determination and
then issue emissions standards. In addition, they contend, the
endangerment proposal and the emissions standards proposal need to be
issued together so commenters can fully understand the implications of
the endangerment determination. Failure to do so, they argue, deprives
the commenters of the opportunity to assess the regulations that will
presumably follow from an endangerment finding. They also argue that
the expected overlap between reductions in emissions of greenhouse
gases from CAA section 202(a) standards issued by EPA and CAFE
standards issued by DOT calls into question the basis for the CAA
section 202(a) standards and the related endangerment finding, and that
EPA is improperly motivated by an attempt to trigger a cascade of
regulations under the CAA and/or to promote legislation by Congress.
EPA disagrees with the commenters' claims and arguments. The text
of CAA section 202(a) is silent on this issue. It does not specify the
timing of an endangerment finding, other than to be clear that
emissions standards may not be issued unless such a determination has
been made. EPA is exercising the procedural discretion that is provided
by CAA section 202(a)'s lack of specific direction. The text of CAA
section 202(a) envisions two separate actions by the Administrator: (1)
A determination on whether emissions from classes or categories of new
motor vehicles cause or contribute to air pollution that may reasonably
be anticipated to endanger, and (2) a separate decision on issuance of
appropriate emissions standards for such classes or categories. The
procedure followed in this rulemaking, and the companion rulemaking
involving emissions standards for light duty motor vehicles, is
consistent with CAA section 202(a). EPA will issue final emissions
standards for new motor
[[Page 66502]]
vehicles only if affirmative findings are made concerning contribution
and endangerment, and such emissions standards will not be finalized
prior to making any such determinations. While it would also be
consistent with CAA section 202(a) to issue the greenhouse gas
endangerment and contribution findings and emissions standards for new
light-duty vehicles in the same rulemaking, e.g., a single proposal
covering them and a single final rule covering them, nothing in CAA
section 202(a) requires such a procedural approach, and nothing in the
approach taken in this case violates the text of CAA section 202(a).
Since Congress was silent on this issue, and more than one procedural
approach may accomplish the requirements of CAA section 202(a), EPA has
the discretion to use the approach considered appropriate in this case.
Once the final affirmative contribution and endangerment findings are
made, EPA has the authority to issue the final emissions standards for
new light-duty motor vehicles; however, as the Supreme Court has noted,
the agency has `significant latitude as to the manner, timing, [and]
content * * * of its regulations . * * *' Massachusetts v. EPA, 549
U.S. at 533. That includes the discretion to issue them in a separate
rulemaking.
Commenters' argument would also lead to the conclusion that EPA
could not make an endangerment finding for the entire category of new
motor vehicles, as it is doing here, unless EPA also conducted a
rulemaking that set emissions standards for all the classes and
categories of new motor vehicles at the same time. This narrow
procedural limitation would improperly remove discretion that CAA
section 202(a) provides to EPA.
EPA has the discretion under CAA section 202(a) to consider classes
or categories of new motor vehicles separately or together in making a
contribution and endangerment determination. This discretion would be
removed under commenters' interpretation, by limiting this to only
those cases in which EPA was also ready to issue emissions standards
for all of the classes or categories covered by the endangerment
finding. However, nothing in the text of CAA section 202(a) places such
a limit on EPA's discretion in determining how to group classes or
categories of new motor vehicles for purposes of the contribution and
endangerment findings. This limitation would not be appropriate,
because the issues of contribution and endangerment are separate and
distinct from the issues of setting emissions standards. EPA, in this
case, is fully prepared to go forward with the contribution and
endangerment determination, while it is not ready to proceed with
rulemaking for each and every category of new motor vehicles in the
first rulemaking to set emissions standards. Section 202(a) of the CAA
provides EPA discretion with regard to when and how it conducts its
rulemakings to make contribution and endangerment findings, and to set
emissions standards, and the text of CAA section 202(a) does not
support commenters attempt to limit such discretion.
Concerns have been raised that the failure to issue the proposed
endangerment finding and the proposed emissions standard together
preclude commenters from assessing and considering the implications of
the endangerment finding and the regulations that would likely flow
from such a finding. However, commenters have failed to explain how
this interferes in any way with their ability to comment on the
endangerment finding. In fact it does not interfere, because the two
proposals address separate and distinct issues. The endangerment
finding concerns the contribution of new motor vehicles to air
pollution and the effect of that air pollution on public health or
welfare. The emissions standards, which have been proposed (74 FR
49454, September 28, 2009), concern the appropriate regulatory
emissions standards if affirmative findings are made on contribution
and endangerment. These two proposals address different issues. While
commenters have the opportunity to comment on the proposed emissions
standards in that rulemaking, they have not shown, and cannot show,
that they need to have the emissions standards proposal before them in
order to provide relevant comments on the proposed contribution or
endangerment findings. Further discussion of this issue can be found in
Section II of these Findings, and discussion of the timing of this
action and its relationship to other CAA provisions and Congressional
action can be found in Section III of these Findings and Volume 11 of
the Response to Comments document.
c. The Administrator's Final Decision Was Not Preordained by the
President's May Vehicle Announcement
EPA received numerous comments arguing that the President's
announcement of a new ``National Fuel Efficiency Policy'' on May 19,
2009 seriously undermines EPA's ability to provide objective
consideration of and a legally adequate response to comments objecting
to the previously proposed endangerment findings.
Commenters' conclusion is based on the view that the President's
announced policy requires EPA to promulgate greenhouse gas emissions
standards under CAA section 202(a), that the President's and
Administrator Jackson's announcement indicated that the endangerment
rulemaking was but a formality and that a final endangerment finding
was a fait accompli. Commenters argue that this means the result of
this rulemaking has been preordained and the merits of the issues have
been prejudged.
EPA disagrees. Commenters' arguments wholly exaggerate and
mischaracterize the circumstances. In the April 24, 2009 endangerment
proposal EPA was clear that the two steps in the endangerment provision
have to be satisfied in order for EPA to issue emissions standards for
new motor vehicles under CAA section 202(a) (74 FR at 18888, April 24,
2009). This was repeated when EPA issued the Notice of Upcoming Joint
Rulemaking to Establish Vehicle GHG Emissions and CAFE Standards (74 FR
24007 May 22, 2009) (Notice of Intent or NOI). This was repeated again
when EPA issued proposed greenhouse gas emissions standards for certain
new motor vehicles (74 FR 49454, September 28, 2009). EPA has
consistently made it clear that issuance of new motor vehicle standards
requires and is contingent upon satisfaction of the two-part
endangerment test.
On May 19, 2009 EPA issued the joint Notice of Intent, which
indicated EPA's intention to propose new motor vehicle standards. All
of the major motor vehicle manufacturers, their trade associations, the
State of California, and several environmental organizations announced
their full support for the upcoming rulemaking. Not surprisingly, on
the same day the President also announced his full support for this
action. Commenters, however, erroneously equate this Presidential
support with a Presidential directive that requires EPA to prejudge and
preordain the result of this rulemaking.
The only evidence they point to are simply indications of
Presidential support. Commenters point to a press release, which
unsurprisingly refers to the Agency's announcement as delivering on the
President's commitment to enact more stringent fuel economy standards,
by bringing ``all stakeholders to the table and [coming] up with a
plan'' for solving a serious problem. The plan that was announced, of
course, was a plan to conduct notice and comment
[[Page 66503]]
rulemaking. The press release itself states that President Obama ``set
in motion a new national policy,'' with the policy ``aimed'' at
reducing greenhouse gas emissions for new cars and trucks. What was
``set in motion'' was a notice and comment rulemaking described in the
NOI issued by EPA on the same day. Neither the President nor EPA
announced a final rule or a final direction that day, but instead did
no more than announce a plan to go forward with a notice and comment
rulemaking. That is how the plan ``delivers on the President's
commitment'' to enact more stringent standards. The announcement was
that a notice and comment rulemaking would be initiated with the aim of
adopting certain emissions standards.
That is no different from what EPA or any other agency states when
it issues a notice of proposed rulemaking. It starts a process that has
the aim of issuing final regulations if they are deemed appropriate at
the end of the public process. The fact that an Agency proposes a
certain result, and expects that a final rule will be the result of
setting such a process in motion, is the ordinary course of affairs in
notice and comment rulemakings. This does not translate into prejudging
the final result or having a preordained result that de facto negates
the public comment process. The President's press release of May 19,
2009 was a recognition that this notice and comment rulemaking process
would be set in motion, as well as providing his full support for the
Agency to go forward in this direction; it was no more than that.
The various stakeholders who announced their support for the plan
that had been set in motion all recognized that full notice and comment
rulemaking was part of the plan, and they all reserved their rights to
participate in such notice and comment rulemaking. For example, see the
letter of support from Ford Motor Company, which states that ``Ford
fully supports proposal and adoption of such a National Program, which
we understand will be subject to full notice-and-comment rulemaking,
affording all interested parties including Ford the right to
participate fully, comment, and submit information, the results of
which are not pre-determined but depend upon processes set by law.''
d. The Notice and Comment Period Was Adequate
Many commenters argue that the 60-day comment period was
inadequate. Commenters claim that a 60-day period was insufficient time
to fully evaluate the science and other information that informed the
Administrator's proposal. Some commenters assert that because the
comment period for the Proposed Finding substantially overlapped with
the comment period for the Mandatory Greenhouse Gas Reporting Rule, as
well as Congress' consideration of climate legislation, their ability
to fully participate in the notice and comment period was ``seriously
compromised.'' Moreover, they continue, because EPA had not yet
proposed CAA section 202(a) standards, there was no valid reason to
fail to extend the comment period. Several commenters and other
entities had also requested that EPA extend the comment period.
Some commenters assert that the notice provided by this rulemaking
was ``defective'' because the Federal Register notice announcing the
proposal had an error in the e-mail address for the docket. At least
one commenter suggests that this error deprives potential commenters of
their Due Process under the Fifth Amendment of the Constitution, citing
Armstrong v. Manzo, 380 U.S. 545, 552 (1965), and that failure to
``correct'' the minor typographical error in the e-mail address and
extend the comment period would make the rule ``subject to reversal''
in violation of the CAA, Administrative Procedure Act (APA), the Due
Process clause of the Constitution, and EO 12866.
Finally, for many of the same reasons that commenters argue a 60-
day comment period was inadequate, several commenters request that EPA
reopen and/or extend the comment period. One commenter requests that
the comment period be reopened because there was new information
regarding data used by EPA in the Proposed Findings. In particular, the
commenter alleges that it recently became aware that one of the sources
of global climate data had destroyed the raw data for its data set of
global surface temperatures. The commenter argues that this alleged
destruction of raw data violates scientific standards, calls into
question EPA's reliance on that data in these Findings, and
necessitates a reopening of the proceedings. Other commenters request
that the comment period be extended and/or reopened due to the release
of a Federal government document on the impact of climate change in the
United States near the end of the comment period, as well as the
release of an internal EPA staff document discussing the science.
The official public comment period on the proposed rule was
adequate. First, a 60-day comment period satisfies the procedural
requirements of CAA section 307 of the CAA, which requires a 30-day
comment period, and that the docket be kept open to receive rebuttal or
supplemental information as follow-up to any hearings for 30 days
following the hearings. EPA met those obligations here--the comment
period opened on April 24, 2009, the last hearing was on May 21, 2009
and the comment period closed June 23, 2009.
Second, as explained in letters denying requests to extend the
comment period, a very large part of the information and analyses for
the Proposed Findings had been previously released in July 30, 2008, as
part of the Advance Notice of Proposed Rulemaking: Regulating
Greenhouse Gas Emissions under the Clean Air Act (ANPR) (73 FR 44353).
The public comment period for the ANPR is discussed above in Section
I.C.1 of these Findings. The Administrator explained that the comment
period for that ANPR was 120 days and that the major recent scientific
assessments that EPA relied upon in the TSD released with the ANPR had
previously each gone through their own public review processes and have
been publicly available for some time. In other words, EPA has provided
ample time for review, particularly with regard to the technical
support for the Findings. See, for example, EPA Letter to Congressman
Issa dated June 17, 2009, a copy of which is available at http://epa.gov/climatechange/endangerment.html.
Moreover, the comment period was not rendered insufficient merely
because other climate-related proceedings were occurring
simultaneously.
While one commenter suggests that the convergence of several
different climate-related activities has ``seriously compromised''
their ability to participate in the comment process, that commenter was
able to submit an 89 page comment on this proposal alone. Moreover, it
is hardly rare that more than one rule is out for comment at the same
time. As noted above, EPA has received a substantial number of
significant comments on the Proposed Findings, and has thoroughly
considered and responded to significant comments.
EPA finds no evidence that a typographical error in the docket e-
mail address of the Federal Register notice announcing the proposal
prevented the public from having a meaningful opportunity to comment,
and therefore deprived them of due process. Although the minor error--
which involved a word processing auto-correction that turned a short
dash into a long dash--appeared in the FR version of the Proposed
Findings, the e-mail address is correct
[[Page 66504]]
in the signature version of the Proposed Findings posted on EPA's Web
site until publication in the Federal Register, and in the
``Instructions for Submitting Written Comments'' document on the Web
site for the rulemaking. EPA has received over 190,000 e-mails to the
docket e-mail address to date, so the minor typographical error
appearing in only one location has not been an impediment to interested
parties' e-mailing comments. Moreover, EPA provided many other avenues
for interested parties to submit comments in addition to the docket e-
mail address, including via www.regulations.gov, mail, and fax; each of
these options have been utilized by many commenters. EPA is confident
that the minor typographical error did not prevent anyone from
submitting written comments, by e-mail or otherwise, and that the
public was provided ``meaningful participation in the regulatory
process'' as mentioned in EO 12866.
Our response regarding the request to reopen the comment period due
to concerns about alleged destruction of raw global surface data is
discussed more fully in the Response to Comments document, Volume 11.
The commenter did not provide any compelling reason to conclude that
the absence of these data would materially affect the trends in the
temperature records or conclusions drawn about them in the assessment
literature and reflected in the TSD. The Hadley Centre/Climate Research
Unit (CRU) temperature record (referred to as HadCRUT) is just one of
three global surface temperature records that EPA and the assessment
literature refer to and cite. National Oceanic and Atmospheric
Administration (NOAA) and National Aeronautics and Space Administration
(NASA) also produce temperature records, and all three temperature
records have been extensively peer reviewed. Analyses of the three
global temperature records produce essentially the same long-term
trends as noted in the Climate Change Science Program (CCSP) (2006)
report ``Temperature Trends in the Lower Atmosphere,'' IPCC (2007), and
NOAA's study \5\ ``State of the Climate in 2008''. Furthermore, the
commenter did not demonstrate that the allegedly destroyed data would
materially alter the HadCRUT record or meaningfully hinder its
replication. The raw data, a small part of which has not been public
(for reasons described at: https://www.uea.ac.uk/mac/comm/media/press/2009/nov/CRUupdate), are available in a quality-controlled (or
homogenized, value-added) format and the methodology for developing the
quality-controlled data is described in the peer reviewed literature
(as documented at http://www.cru.uea.ac.uk/cru/data/temperature/).
---------------------------------------------------------------------------
\5\ Peterson, T.C., and M.O. Baringer (Eds.) (2009) State of the
Climate in 2008. Bull. Amer. Meteor. Soc., 90, S1-S196.
---------------------------------------------------------------------------
The release of the U.S. Global Climate Research Program (USGCRP)
report on impacts of climate change in the United States in June 2009
also did not necessitate extending the comment period. This report was
issued by the USGCRP, formerly the Climate Change Science Program
(CCSP), and synthesized information contained in prior CCSP reports and
other synthesis reports, many of which had already been published (and
were included in the TSD for the Proposed Findings). Further, the
USGCRP report itself underwent notice and comment before it was
finalized and released.
Regarding the internal EPA staff paper that came to light during
the comment period, several commenters submitted a copy of the EPA
staff paper with their comments; EPA's response to the issues raised by
the staff paper are discussed in the Response to Comments document,
Volume 1. The fact that some internal agency deliberations were made
public during the comment period does not in and of itself call into
question those deliberations. As our responses to comments explain, EPA
considered the concerns noted in the staff paper during the proposal
stage, as well as when finalizing the Findings. There was nothing about
those internal comments that required an extension or reopening of the
comment period.
Thus, the opportunity for comment fully satisfies the CAA and
Constitutional requirement of Due Process. Cases cited by commenters do
not indicate otherwise. The comment period and thorough response to
comment documents in the docket indicate that EPA has given people an
opportunity to be heard in a ``meaningful time and a meaningful
matter.'' Armstrong v. Manzo, 380 U.S. 545, 552 (1965). Interested
parties had full notice of the rulemaking proceedings and a significant
opportunity to participate through the comment process and multiple
hearings.
For all the above reasons, EPA's denial of the requests for
extension or reopening of the comment period was entirely reasonable in
light of the extensive opportunity for public comment and heavy amount
of public participation during the comment period. EPA has fully
complied with all applicable public participation requirements for this
rulemaking.
e. These Findings Did Not Necessitate a Formal Rulemaking Under the
Administrative Procedure Act
One commenter, with the support of others, requests that EPA
undertake a formal rulemaking process for the Findings, on the record,
in accordance with the procedures described in sections 556-557 of the
Administrative Procedure Act (APA). The commenter requests a multi-step
process, involving additional public notice, an on-the-record
proceeding (e.g., formal administrative hearing) with the right of
appeal, utilization of the Clean Air Scientific Advisory Committee
(CASAC) and its advisory proceedings, and designation of
representatives from other executive branch agencies to participate in
the formal proceeding and any CASAC advisory proceeding.
The commenter asserts that while EPA is not obligated under the CAA
to undertake these additional procedures, the Agency nonetheless has
the legal authority to engage in such a proceeding. The commenter
believes this proceeding would show that EPA is ``truly committed to
scientific integrity and transparency.'' The commenter cites several
cases to argue that refusal to proceed on the record would be
``arbitrary and capricious'' or would be an ``abuse of discretion.''
The allegation at the core of the commenter's argument is that profound
and wide-ranging scientific uncertainties exist in the Proposed
Findings and in the impacts on health and welfare discussed in the TSD.
To support this argument, the commenter provides lengthy criticisms of
the science. The commenter also argues that the regulatory cascade that
would be ``unleashed'' by a positive endangerment finding warrants the
more formal proceedings.
Finally, the commenter suggests that EPA engage in ``formal
rulemaking'' procedures in part due to the Administrative Conference of
the United States' (ACUS) recommended factors for engaging in formal
rulemaking. The commenter argues that the current action is
``complex,'' ``open-ended,'' and the costs that errors in the action
may pose are ``significant.''
EPA is denying the request to undertake an ``on the record'' formal
rulemaking. EPA is under no obligation to follow the extraordinarily
rarely used formal rulemaking provisions of the APA. First, CAA section
307(d) of the CAA clearly states that the rulemaking provisions of CAA
section 307(d), not APA sections 553 through 557, apply to certain
specified actions, such as this
[[Page 66505]]
one. EPA has satisfied all the requirements of CAA section 307(d).
Indeed, the commenter itself ``is not asserting that the Clean Air Act
expressly requires'' the additional procedures it requests. Moreover,
the commenter does not discuss how the suggested formal proceeding
would fit into the informal rulemaking requirements of CAA section
307(d) that do apply.
Formal rulemaking is very rarely used by Federal agencies. The
formal rulemaking provisions of the APA are only triggered when the
statute explicitly calls for proceedings ``on the record after
opportunity for an agency hearing.'' United States v. Florida East
Coast Ry. Co., 410 U.S. 224, 241 (1973). The mere mention of the word
``hearing'' does not trigger the formal rulemaking provisions of the
APA. Id. The CAA does not include the statutory phrase required to
trigger the formal rulemaking provisions of the APA (and as noted above
the APA does not apply in the first place). Congress specified that
certain rulemakings under the CAA follow the rulemaking procedures
outlined in CAA section 307(d) rather than the APA ``formal
rulemaking'' commenter suggests.
Despite the inapplicability of the formal rulemaking provisions to
this action, commenters suggest that to refuse to voluntarily undertake
rulemaking provisions not preferred by Congress would make EPA's
rulemaking action an ``abuse of discretion.'' EPA disagrees with this
claim, and cases cited by the commenter do not indicate otherwise. To
support the idea that an agency decision to engage in informal
rulemaking could be an abuse of discretion, commenter cites Ford Motor
Co. v. FTC, 673 F.2d 1008 (9th Cir. 1981). In Ford Motor Co., the court
ruled that the FTC's decision regarding an automobile dealership should
have been resolved through a rulemaking rather than an individualized
adjudication. Id. at 1010. In that instance, the court favored
``rulemaking'' over adjudication--not ``formal rulemaking'' over the
far more common ``informal rulemaking.'' The case stands only for the
non-controversial proposition that sometimes agency use of
adjudications may rise to an abuse of discretion where a rulemaking
would be more appropriate--whether formal or informal. The Commenter
does not cite a single judicial opinion stating that an agency abused
its discretion by following the time-tested and Congressionally-favored
informal rulemaking provisions of the CAA or the APA instead of the
rarely used formal APA rulemaking provisions.
The commenter also alludes to the possibility that the choice of
informal rulemaking may be ``arbitrary and capricious. EPA disagrees
that the choice to follow the frequently used, and CAA required,
informal rulemaking procedures is arbitrary and capricious. The
commenter cites Vermont Yankee Nuclear Power Corp. v. NRDC, 435 U.S.
519 (1978) for the proposition that ``extremely compelling
circumstances'' could lead to a court overturning agency action for
declining to follow extraneous procedures. As the commenter notes, in
Vermont Yankee the Supreme Court overturned a lower court decision for
imposing additional requirements not required by applicable statutes.
Even if the dicta in Vermont Yankee could be applied contrary to the
holding of the case in the way the commenter suggests, EPA's decision
to follow frequently used informal rulemaking procedures for this
action is highly reasonable.
As for the ACUS factors the commenter cites in support of its
request, as the commenter notes, the ACUS factors are mere
recommendations. While EPA certainly respects the views of ACUS, the
recommendations are not binding on the Agency. In addition, EPA has
engaged in a thorough, traditional rulemaking process that ensures that
any concerns expressed by the commenter have been addressed. EPA has
fully satisfied all applicable law in their consideration of this
rulemaking.
Finally, as explained in Section III of these Findings and the
Response to Comments document, EPA's approach to evaluating the
evidence before it was entirely reasonable, and did not require a
formal hearing. EPA relied primarily on robust synthesis reports that
have undergone peer review and comment. The Agency also carefully
considered the comments received on the Proposed Findings and TSD,
including review of attached studies and documents. The public has had
ample opportunity to provide its views on the science, and the record
supporting these final findings indicates that EPA carefully considered
and responded to significant public comments. To the extent the
commenter's concern is that a formal proceeding will help ensure the
right action in response to climate change is taken, that is not an
issue for these Findings. As discussed in Section III of these
Findings, this science-based judgment is not the forum for considering
the potential mitigation options or their impact.
II. Legal Framework for This Action
As discussed in the Proposed Findings, two statutory provisions of
the CAA govern the Administrator's Findings. Section 202(a) of the CAA
sets forth a two-part test for regulatory action under that provision:
Endangerment and cause or contribute. Section 302 of the CAA contains
definitions of the terms ``air pollutant'' and ``effects on welfare''.
Below is a brief discussion of these statutory provisions and how they
govern the Administrator's decision, as well as a summary of
significant legal comments and EPA's responses to them.
A. Section 202(a) of the CAA--Endangerment and Cause or Contribute
1. The Statutory Framework
Section 202(a)(1) of the CAA states that:
The Administrator shall by regulation prescribe (and from time to
time revise) standards applicable to the emission of any air pollutant
from any class or classes of new motor vehicles or new motor vehicle
engines, which in [her] judgment cause, or contribute to, air pollution
which may reasonably be anticipated to endanger public health or
welfare.
Based on the text of CAA section 202(a) and its legislative
history, the Administrator interprets the two-part test as follows.
Further discussion of this two-part test can be found in Section II of
the preamble for the Proposed Findings. First, the Administrator is
required to protect public health and welfare, but she is not asked to
wait until harm has occurred. EPA must be ready to take regulatory
action to prevent harm before it occurs. Section 202(a)(1) requires the
Administrator to ``anticipate'' ``danger'' to public health or welfare.
The Administrator is thus to consider both current and future risks.
Second, the Administrator is to exercise judgment by weighing risks,
assessing potential harms, and making reasonable projections of future
trends and possibilities. It follows that when exercising her judgment
the Administrator balances the likelihood and severity of effects. This
balance involves a sliding scale; on one end the severity of the
effects may be of great concern, but the likelihood low, while on the
other end the severity may be less, but the likelihood high. Under
either scenario, the Administrator is permitted to find endangerment.
If the harm would be catastrophic, the Administrator is permitted to
find endangerment even if the likelihood is small.
Because scientific knowledge is constantly evolving, the
Administrator may be called upon to make decisions while recognizing
the uncertainties and
[[Page 66506]]
limitations of the data or information available, as risks to public
health or welfare may involve the frontiers of scientific or medical
knowledge. At the same time, the Administrator must exercise reasoned
decision making, and avoid speculative inquiries. Third, as discussed
further below, the Administrator is to consider the cumulative impact
of sources of a pollutant in assessing the risks from air pollution,
and is not to look only at the risks attributable to a single source or
class of sources. Fourth, the Administrator is to consider the risks to
all parts of our population, including those who are at greater risk
for reasons such as increased susceptibility to adverse health effects.
If vulnerable subpopulations are especially at risk, the Administrator
is entitled to take that point into account in deciding the question of
endangerment. Here too, both likelihood and severity of adverse effects
are relevant, including catastrophic scenarios and their probabilities
as well as the less severe effects. As explained below, vulnerable
subpopulations face serious health risks as a result of climate change.
In addition, by instructing the Administrator to consider whether
emissions of an air pollutant cause or contribute to air pollution, the
statute is clear that she need not find that emissions from any one
sector or group of sources are the sole or even the major part of an
air pollution problem. The use of the term ``contribute'' clearly
indicates a lower threshold than the sole or major cause. Moreover, the
statutory language in CAA section 202(a) does not contain a modifier on
its use of the term contribute. Unlike other CAA provisions, it does
not require ``significant'' contribution. See, e.g., CAA sections
111(b); 213(a)(2), (4). To be sure, any finding of a ``contribution''
requires some threshold to be met; a truly trivial or de minimis
``contribution'' might not count as such. The Administrator therefore
has ample discretion in exercising her reasonable judgment in
determining whether, under the circumstances presented, the cause or
contribute criterion has been met. Congress made it clear that the
Administrator is to exercise her judgment in determining contribution,
and authorized regulatory controls to address air pollution even if the
air pollution problem results from a wide variety of sources. While the
endangerment test looks at the entire air pollution problem and the
risks it poses, the cause or contribute test is designed to authorize
EPA to identify and then address what may well be many different
sectors or groups of sources that are each part of--and thus
contributing to--the problem.
This framework recognizes that regulatory agencies such as EPA must
be able to deal with the reality that ``[m]an's ability to alter his
environment has developed far more rapidly than his ability to foresee
with certainty the effects of his alterations.'' See Ethyl Corp v. EPA,
541 F.2d 1, 6 (DC Cir.), cert. denied 426 U.S. 941 (1976). Both ``the
Clean Air Act `and common sense * * * demand regulatory action to
prevent harm, even if the regulator is less than certain that harm is
otherwise inevitable.' '' See Massachusetts v. EPA, 549 U.S. at 506,
n.7 (citing Ethyl Corp.).
The Administrator recognizes that the context for this action is
unique. There is a very large and comprehensive base of scientific
information that has been developed over many years through a global
consensus process involving numerous scientists from many countries and
representing many disciplines. She also recognizes that there are
varying degrees of uncertainty across many of these scientific issues.
It is in this context that she is exercising her judgment and applying
the statutory framework. As discussed in the Proposed Findings, this
interpretation is based on and supported by the language in CAA section
202(a), its legislative history and case law.
2. Summary of Response to Key Legal Comments on the Interpretation of
the CAA Section 202(a) Endangerment and Cause or Contribute Test
EPA received numerous comments regarding the interpretation of CAA
section 202(a) set forth in the Proposed Findings. Below is a brief
discussion of some of the key adverse legal comments and EPA's
responses. Other key legal comments and EPA's responses are provided in
later sections discussing the Administrator's findings.
Additional and more detailed summaries and responses can be found
in the Response to Comments document. As noted in the Response to
Comments document, EPA also received comments supporting its legal
interpretations.
a. The Administrator Properly Interpreted the Precautionary and
Preventive Nature of the Statutory Language
Various commenters argue either that the endangerment test under
CAA section 202(a) is not precautionary and preventive in nature, or
that EPA's interpretation and application is so extreme that it is
contrary to what Congress intended in 1977, and effectively guarantees
an affirmative endangerment finding. Commenters also argue that the
endangerment test improperly shifts the burdens to the opponents of an
endangerment finding and is tantamount to assuming the air pollution is
harmful unless it is shown to be safe.
EPA rejects the argument that the endangerment test in CAA section
202(a) is not precautionary or preventive in nature. As discussed in
more detail in the proposal, Congress relied heavily on the en banc
decision in Ethyl when it revised section 202(a) and other CAA
provisions to adopt the current language on endangerment and
contribution. 74 FR 18886, 18891-2. The Ethyl court could not have been
clearer on the precautionary nature of a criteria based on
endangerment. The court rejected the argument that EPA had to find
actual harm was occurring before it could make the required
endangerment finding. The court stated that:
The Precautionary Nature of ``Will Endanger.'' Simply as a
matter of plain meaning, we have difficulty crediting petitioners'
reading of the ``will endanger'' standard. The meaning of
``endanger'' is not disputed. Case law and dictionary definition
agree that endanger means something less than actual harm. When one
is endangered, harm is threatened; no actual injury need ever occur.
Thus, for example, a town may be ``endangered'' by a threatening
plague or hurricane and yet emerge from the danger completely
unscathed. A statute allowing for regulation in the face of danger
is, necessarily, a precautionary statute. Regulatory action may be
taken before the threatened harm occurs; indeed, the very existence
of such precautionary legislation would seem to demand that
regulatory action precede, and, optimally, prevent, the perceived
threat. As should be apparent, the ``will endanger'' language of
Section 211(c)(1)(A) makes it such a precautionary statute. Ethyl at
13 (footnotes omitted).
Similarly, the court stated that ``[i]n sum, based on the plain
meaning of the statute, the juxtaposition of CAA section 211 with CAA
sections 108 and 202, and the Reserve Mining precedent, we conclude
that the ``will endanger'' standard is precautionary in nature and does
not require proof of actual harm before regulation is appropriate.''
Ethyl at 17. It is this authority to act before harm has occurred that
makes it a preventive, precautionary provision.
It is important to note that this statement was in the context of
rejecting an argument that EPA had to prove actual harm before it could
adopt fuel control regulations under then CAA section 211(c)(1). The
court likewise rejected the argument that EPA had to show that such
harm was ``probable.''
[[Page 66507]]
The court made it clear that determining endangerment entails judgments
involving both the risk or likelihood of harm and the severity of the
harm if it were to occur. Nowhere did the court indicate that the
burden was on the opponents of an endangerment finding to show that
there was no endangerment. The opinion focuses on describing the burden
the statute places on EPA, rejecting Ethyl's arguments of a burden to
show actual or probable harm.
Congress intentionally adopted a precautionary and preventive
approach. It stated that the purpose of the 1977 amendments was to
``emphasize the preventive or precautionary nature of the act, i.e., to
assure that regulatory action can effectively prevent harm before it
occurs; to emphasize the predominate value of protection to public
health.'' \6\ Congress also stated that it authorized the Administrator
to weigh risks and make projections of future trends, a ``middle road
between those who would impose a nearly impossible standard of proof on
the Administrator before he may move to protect public health and those
who would shift the burden of proof for all pollutants to make the
pollutant source prove the safety of its emissions as a condition of
operation.'' Leg. His. at 2516.
---------------------------------------------------------------------------
\6\ The Supreme Court recognized that the current language in
section 202(a), adopted in 1977, is ``more protective'' than the
1970 version that was similar to the section 211 language before the
DC Circuit in Ethyl. Massachusetts v. EPA, 549 U.S. at 506, fn 7.
---------------------------------------------------------------------------
Thus, EPA rejects commenters' arguments. Congress intended this
provision to be preventive and precautionary in nature, however it did
not shift the burden of proof to opponents of an endangerment finding
to show safety or no endangerment. Moreover, as is demonstrated in the
following, EPA has not shifted the burden of proof in the final
endangerment finding, but rather is weighing the likelihood and
severity of harms to arrive at the final finding. EPA has not applied
an exaggerated or dramatically expanded precautionary principle, and
instead has exercised judgment by weighing and balancing the factors
that are relevant under this provision.
b. The Administrator Does Not Need To Find That the Control Measures
Following an Endangerment Finding Would Prevent at Least a Substantial
Part of the Danger in Order To Find Endangerment
Several commenters argue that it is unlawful for EPA to make an
affirmative endangerment finding unless EPA finds that the regulatory
control measures contemplated to follow such a finding would prevent at
least a substantial part of the danger from the global climate change
at which the regulation is aimed. This hurdle is also described by
commenters as the regulation ``achieving the statutory objective of
preventing damage'', or ``fruitfully attacking'' the environmental and
public health danger at hand by meaningfully and substantially reducing
it. Commenters point to Ethyl Corp. v. EPA, 541 F.2d 1 (DC Cir. 1976)
(en banc) as support for this view, as well as portions of the
legislative history of this provision.
Commenters contend that EPA has failed to show that this required
degree of meaningful reduction of endangerment would be achieved
through regulation of new motor vehicles based on an endangerment
finding. In making any such showing, commenters argue that EPA would
need to account for the following: (1) The fact that any regulation
would be limited to new motor vehicles, if not the subset of new motor
vehicles discussed in the President's May 2009 announcement, (2) any
increase in emissions from purchasers delaying purchases of new
vehicles subject to any greenhouse gas emissions standards, or
increasing the miles traveled of new vehicles with greater fuel
economy, (3) the fact that only a limited portion of the new motor
vehicle emissions of greenhouse gases would be controlled, (4) the fact
that CAFE standards would effectively achieve the same reductions, and
(5) the fact that any vehicle standards would not themselves reduce
global temperatures. Some commenters refer to EPA's proposal for
greenhouse gas emissions standards for new motor vehicles as support
for these arguments, claiming the proposed new motor vehicle emission
standards are largely duplicative of the standards proposed by the
National Highway Traffic Safety Administration (NHTSA), and the
estimates of the impacts of the proposed standards confirm that EPA's
proposed standards cannot ``fruitfully attack'' global climate change
(74 FR 49454, September 28, 2009).
Commenters attempt to read into the statute a requirement that is
not there. EPA interprets the endangerment provision of CAA section
202(a) as not requiring any such finding or showing as described by
commenters. The text of CAA section 202(a) does not support such an
interpretation. The endangerment provision calls for EPA, in its
judgment, to determine whether air pollution is reasonably anticipated
to endanger public health or welfare, and whether emissions from
certain sources cause or contribute to such air pollution. If EPA makes
an affirmative finding, then it shall set emissions standards
applicable to emissions of such air pollutants from new motor vehicles.
There is no reference in the text of the endangerment or cause or
contribute provision to anything concerning the degree of reductions
that would be achieved by the emissions standards that would follow
such a finding. The Administrator's judgment is directed at the issues
of endangerment and cause or contribute, not at how effective the
resulting emissions control standards will be.
As in the several other similar provisions adopted in the 1977
amendments, in CAA section 202(a) Congress explicitly separated two
different decisions to be made, providing different criteria for them.
The first decision involves the air pollution and the endangerment
criteria, and the contribution to the air pollution by the sources. The
second decision involves how to regulate the sources to control the
emissions if an affirmative endangerment and contribution finding are
made. In all of the various provisions, there is broad similarity in
the phrasing of the endangerment and contribution decision. However,
for the decision on how to regulate, there are a wide variety of
different approaches adopted by Congress. In some case, EPA has
discretion whether to issue standards or not, while in other cases, as
in CAA section 202(a), EPA is required to issue standards. In some
cases, the regulatory criteria are general, as in CAA section 202(a);
in others, they provide significantly more direction as to how
standards are to be set, as in CAA section 213(a)(4).
As the Supreme Court made clear in Massachusetts v. EPA, EPA's
judgment in making the endangerment and contribution findings is
constrained by the statute, and EPA is to decide these issues based
solely on the scientific and other evidence relevant to that decision.
EPA may not ``rest[] on reasoning divorced from the statutory text,''
and instead EPA's exercise of judgment must relate to whether an air
pollutant causes or contributes to air pollution that endangers.
Massachusetts v. EPA, 549 U.S. at 532. As the Supreme Court noted, EPA
must ``exercise discretion within defined statutory limits.'' Id. at
533. EPA's belief one way or the other regarding whether regulation of
greenhouse gases from new motor vehicles would be ``effective'' is
irrelevant in making the endangerment and contribution decisions before
EPA. Id. Instead ``[t]he statutory question is
[[Page 66508]]
whether sufficient information exists to make an endangerment finding''
Id. at 534.
The effectiveness of a potential future control strategy is not
relevant to deciding whether air pollution levels in the atmosphere
endanger. It is also not relevant to deciding whether emissions of
greenhouse gases from new motor vehicles contribute to such air
pollution. Commenters argue that Congress implicitly imposed a third
requirement, that the future control strategy have a certain degree of
effectiveness in reducing the endangerment before EPA could make the
affirmative findings that would authorize such regulation. There is no
statutory text that supports such an interpretation, and the Supreme
Court makes it clear that EPA has no discretion to read this kind of
additional factor into CAA section 202(a)'s endangerment and
contribution criteria. In fact, the Supreme Court rejected similar
arguments that EPA had the discretion to consider various other factors
besides endangerment and contribution in deciding whether to deny a
petition. Massachusetts v. EPA, 549 U.S. at 532-35.
Commenters point to language from the Ethyl case to support their
position, noting that the DC Circuit referred to the emissions control
regulation adopted by EPA under CAA section 211(c) as one that would
``fruitfully attack'' the environmental and public health danger by
meaningfully and substantially reducing the danger. It is important to
understand the context for this discussion in Ethyl. The petitioner
Ethyl Corp. argued that EPA had to show that the health threat from the
emissions of lead from the fuel additive being regulated had to be
considered in isolation, and the threat ``in and of itself'' from the
additive had to meet the test of endangerment in CAA section 211(c).
EPA had rejected this approach, and had interpreted CAA section
211(c)(1) as calling for EPA to look at the cumulative impact of lead,
and to consider the impact of lead from emissions related to use of the
fuel additive in the context all other human exposure to lead. The
court rejected Ethyl's approach and supported EPA's interpretation. The
DC Circuit noted that Congress was fully aware that the burden of lead
on the body was caused by multiple sources and that it would be of no
value to try and determine the effect on human health from the lead
automobile emissions by themselves. The court specifically noted that
``the incremental effect of lead emissions on the total body lead
burden is of no practical value in determining whether health is
endangered,'' but recognized that this incremental effect is of value
``in deciding whether the lead exposure problem can fruitfully be
attacked through control of lead additives.'' Ethyl, 541 F.2d at 31 fn
62. The court made clear that the factor that was critically important
to determining the effectiveness of the resulting control strategy--the
incremental effect of automobile lead emissions on total body burden--
was irrelevant and of no value in determining whether the endangerment
criteria was met. Thus it is clear that the court in Ethyl did not
interpret then CAA section 211(c)(1)(A) as requiring EPA to make a
showing of the effectiveness of the resulting emissions control
strategy, and instead found just the opposite, that the factors that
would determine effectiveness are irrelevant to determining
endangerment.
Commenters also cite to the legislative history, noting that
Congress referred to the ``preventive or precautionary nature of the
Act, i.e., to assure that regulatory action can effectively prevent
harm before it occurs.'' Leg. Hist. at 2516. However, this statement by
Congress is presented as an answer to the question on page 2515,
``Should the Administrator act to prevent harm before it occurs or
should he be authorized to regulate an air pollutant only if he finds
actual harm has already occurred.'' Leg. Hist. at 2515. In this
context, the discussion on page 2516 clearly indicates that there is no
opportunity for prevention or precaution if the test is one of actual
harm already occurring. This discussion does not say or imply that even
if the harm has not occurred, you can not act unless you also show that
your action will effectively address it. This discussion concerns the
endangerment test, not the criteria for standard setting. The criteria
for standard setting address how the agency should act to address the
harm, and as the Ethyl case notes, the factors relevant to how to
``fruitfully attack'' the harm are irrelevant to determining whether
the harm is one that endangers the public health or welfare.
As with current CAA section 202(a), there is no basis to conflate
these two separate decisions and to read into the endangerment criteria
an obligation that EPA show that the resulting emissions control
strategy or strategies will have some significant degree of harm
reduction or effectiveness in addressing the endangerment. The
conflating of the two decisions is not supported in the text of this
provision, by the Supreme Court in Massachusetts v. EPA, by the DC
Circuit in Ethyl, or by Congress in the legislative history of this
provision. It would be an unworkable interpretation, calling for EPA to
project out the result of perhaps not one, but even several, future
rulemakings stretching over perhaps a decade or decades. Especially in
the context of global climate change, the effectiveness of a control
strategy for new motor vehicles would have to be viewed in the context
of a number of future motor vehicle regulations, as well as in the
larger context of the CAA and perhaps even global context. That would
be an unworkable and speculative requirement to impose on EPA as a
precondition to answering the public health and welfare issues before
it, as they are separate and apart from the issues involved with
developing, implementing and evaluating the effectiveness of emissions
control strategies.
c. The Administrator Does Not Need To Find There Is Significant Risk of
Harm
Commenters argue that Congress established a minimum requirement
that there be a ``significant risk of harm'' to find endangerment. They
contend that this requirement stemmed from the Ethyl case, and that
Congress adopted this view. According to the commenters, the risk is
the function of two variables: the nature of the hazard at issue and
the likelihood of its occurrence. Commenters argue that Congress
imposed a requirement that this balance demonstrate a ``significant
risk of harm'' to strike a balance between the precautionary nature of
the CAA and the burdensome economic and societal consequences of
regulation.
There are two basic problems with the commenters' arguments. First,
commenters equate ``significant risk of harm'' as the overall test for
endangerment, however the Ethyl case and the legislative history treat
the risk of harm as only one of the two components that are to be
considered in determining endangerment.--, The two components are the
likelihood or risk of a harm occurring, and the severity of harm if it
were to occur. Second, commenters equate it to a minimum statutory
requirement. However, while the court in the Ethyl case made it clear
that the facts in that case met the then applicable endangerment
criteria, it also clearly said it was not determining what other facts
or circumstances might amount to endangerment, including cases where
the likelihood of a harm occurring was less than a significant risk of
the harm.
In the EPA rulemaking that led to the Ethyl case, EPA stated that
the requirement to reduce lead in gasoline ``is based on the finding
that lead
[[Page 66509]]
particle emissions from motor vehicles present a significant risk of
harm to the health of urban populations, particularly to the health of
city children'' (38 FR 33734, December 6, 1973). The court in Ethyl
supported EPA's determination, and addressed a variety of issues.
First, it determined that the ``will endanger'' criteria of then CAA
section 211(c) was intended to be precautionary in nature. It rejected
arguments that EPA had to show proof of actual harm, or probable harm.
Ethyl, 541 F.2d at 13-20. It was in this context, evaluating
petitioner's arguments on whether the likelihood of a harm occurring
had to rise to the level of actual or probable harm, that the court
approved of EPA's view that a significant risk of harm could satisfy
the statutory criteria. The precautionary nature of the provision meant
that EPA did not need to show that either harm was actually occurring
or was probable.
Instead, the court made it clear that the concept of endangerment
is ``composed of reciprocal elements of risk and harm,'' Ethyl at 18.
This means ``the public health may properly be found endangered both by
a lesser risk of a greater harm and by a greater risk of lesser harm.
Danger depends upon the relation between the risk and harm presented by
each case, and cannot legitimately be pegged to `probable' harm,
regardless of whether that harm be great or small.'' The Ethyl court
pointed to the decision by the 8th Circuit in Reserve Mining Co. v.
EPA, 514 F.2d 492 (8th Cir, 1975), which interpreted similar language
under the Federal Water Pollution Control Act, where the 8th Circuit
upheld an endangerment finding in a case involving ``reasonable medical
concern,'' or a ``potential'' showing of harm. This was further
evidence that a minimum ``probable'' likelihood of harm was not
required.
The Ethyl court made it clear that there was no specific magnitude
of risk of harm occurring that was required. ``Reserve Mining
convincingly demonstrates that the magnitude of risk sufficient to
justify regulation is inversely proportional to the harm to be
avoided.'' Ethyl at 19. This means there is no minimum requirement that
the magnitude of risk be ``significant'' or another specific level of
likelihood of occurrence. You need to evaluate the risk of harm in the
context of the severity of the harm if it were to occur. In the case
before it, the Ethyl court noted that ``the harm caused by lead
poisoning is severe.'' Even with harm as severe as lead poisoning, EPA
did not rely on ``potential'' risk or a ``reasonable medical concern.''
Instead, EPA found that there was a significant risk of this harm to
health. This finding of a significant risk was less than the level of
``probable'' harm called for by the petitioner Ethyl Corporation but
was ``considerably more certain than the risk that justified regulation
in Reserve Mining of a comparably `fright-laden' harm.'' Ethyl at 19-
20. The Ethyl court concluded that this combination of risk (likelihood
of harm) and severity of harm was sufficient under CAA section 211(c).
``Thus we conclude that however far the parameters of risk and harm
inherent in the `will endanger' standard might reach in an appropriate
case, they certainly present a `danger' that can be regulated when the
harm to be avoided is widespread lead poisoning and the risk of that
occurrence is `significant'.'' Ethyl at 20.
Thus, the court made it clear that the endangerment criteria was
intended to be precautionary in nature, that the risk of harm was one
of the elements to consider in determining endangerment, and that the
risk of harm needed to be considered in the context of the severity of
the potential harm. It also concluded that a significant risk of harm
coupled with an appropriate severity of the potential harm would
satisfy the statutory criteria, and in the case before it the
Administrator was clearly authorized to determine endangerment where
there was a significant risk of harm that was coupled with a severe
harm such as lead poisoning.
Importantly, the court also made it clear that it was not
determining a minimum threshold that always had to be met. Instead, it
emphasized that the risk of harm and severity of the potential harm had
to be evaluated on a case by case basis. The court specifically said it
was not determining ``however far the parameters of risk and harm * * *
might reach in an appropriate case.'' Ethyl at 20. Also see Ethyl fn 17
at 13. The court recognized that this balancing of risk and harm ``must
be confined to reasonable limits'' and even absolute certainty of a de
minimis harm might not justify government action. However, ``whether a
particular combination of slight risk and great harm, or great risk and
slight harm constitutes a danger must depend on the facts of each
case.'' Ethyl at fn 32 at 18.\7\
---------------------------------------------------------------------------
\7\ Commenters point to Amer. Farm Bureau Ass'n v. EPA, 559 F.3d
512, 533 (DC Cir. 2009) as supporting their argument. However, in
that case the Court made clear that EPA's action was not subject to
the endangerment criterion in CAA section 108 but instead was
subject to CAA section 109's requirement that the primary NAAQS be
requisite to protect the public health with an adequate margin of
safety. Under that provision and its case law, the Court upheld
EPA's reasoned balancing of the uncertainty regarding the link
between non-urban thoracic coarse PM and adverse health effects, the
large population groups potentially exposed to these particles, and
the nature and degree of the health effects at issue. Citing to
EPA's reasoning at 71 FR 61193 in the final PM rule, the court
explained that EPA need not wait for conclusive proof of harm before
setting a NAAQS under section 109 for this kind of coarse PM. The
Court's reference to EPA's belief that there may be a significant
risk to public health is not stated as any sort of statutory
minimum, but instead refers to the Agency's reasoning at 71 FR
61193, which displays a reasoned balancing of possibility of harm
and severity of harm if it were to occur.
---------------------------------------------------------------------------
In some cases, commenters confuse matters by switching the
terminology, and instead refer to effects that ``significantly harm''
the public health or welfare. As with the reference to ``significant
risk of harm,'' commenters fail to recognize that there are two
different aspects that must be considered, risk of harm and severity of
harm, and neither of these aspects has a requirement that there be a
finding of ``significance.'' The DC Circuit in Ethyl makes clear that
it is the combination of these two aspects that must be evaluated for
purposes of endangerment, and there is no requirement of
``significance'' assigned to either of the two aspects that must
instead be evaluated in combination. Congress addressed concerns over
burdensome economic and societal consequences in the various statutory
provisions that provide the criteria for standard setting or other
agency action if there is an affirmative endangerment finding. Those
statutory provisions, for example, make standard setting discretionary
or specify how cost and other factors are to be taken into
consideration in setting standards. However, the issues of risk of harm
and severity of harm if it were to occur are separate from the issues
of the economic impacts of any resulting regulatory provisions (see
below).
As is clear in the prior summary of the endangerment findings and
the more detailed discussion later, the breadth of the sectors of our
society that are affected by climate change and the time frames at
issue mean there is a very wide range of risks and harms that need to
be considered, from evidence of various harms occurring now to evidence
of risks of future harms. The Administrator has determined that the
body of scientific evidence compellingly supports her endangerment
finding.
B. Air Pollutant, Public Health and Welfare
The CAA defines both ``air pollutant'' and ``effects on welfare.''
We provide both definitions here again for convenience.
Air pollutant is defined as:
[[Page 66510]]
``Any air pollution agent or combination of such agents, including
any physical, chemical, biological, radioactive (including source
material, special nuclear material, and byproduct material) substance
or matter which is emitted into or otherwise enters the ambient air.
Such term includes any precursors to the formation of any air
pollutant, to the extent the Administrator has identified such
precursor or precursors for the particular purpose for which the term
``air pollutant'' is used.'' CAA section 302(g). As the Supreme Court
held, greenhouse gases fit well within this capacious definition. See
Massachusetts v. EPA, 549 U.S. at 532. They are ``without a doubt''
physical chemical substances emitted into the ambient air. Id. at 529.
``Regarding `effects on welfare', the CAA states that [a]ll
language referring to effects on welfare includes, but is not limited
to, effects on soils, water, crops, vegetation, man-made materials,
animals, wildlife, weather, visibility, and climate, damage to and
deterioration of property, and hazards to transportation, as well as
effects on economic values and on personal comfort and well-being,
whether caused by transformation, conversion, or combination with other
air pollutants.'' CAA section 302(h).
As noted in the Proposed Findings, this definition is quite broad.
Importantly, it is not an exclusive list due to the use of the term
``includes, but is not limited to, * * * .'' Effects other than those
listed here may also be considered effects on welfare. Moreover, the
terms contained within the definition are themselves expansive.
Although the CAA defines ``effects on welfare'' as discussed above,
there are no definitions of ``public health'' or ``public welfare'' in
the CAA. The Supreme Court has discussed the concept of public health
in the context of whether costs of implementation can be considered
when setting the health based primary National Ambient Air Quality
Standards. Whitman v. American Trucking Ass'n, 531 U.S. 457 (2001). In
Whitman, the Court imbued the term with its most natural meaning: ``the
health of the public. Id. at 466. In the past, when considering public
health, EPA has looked at morbidity, such as impairment of lung
function, aggravation of respiratory and cardiovascular disease, and
other acute and chronic health effects, as well as mortality. See,
e.g., Final National Ambient Air Quality Standard for Ozone, (73 FR
16436, 2007).
EPA received numerous comments regarding its proposed
interpretations of air pollutant and public health and welfare.
Summaries of key comments and EPA's responses are discussed in Sections
IV and V of these Findings. Additional and more detailed summaries and
responses can be found in the Response to Comments document. As noted
in the Response to Comments document, EPA also received comments
supporting its legal interpretations.
III. EPA's Approach for Evaluating the Evidence Before It
This section discusses EPA's approach to evaluating the evidence
before it, including the approach taken to the scientific evidence, the
legal framework for this decision making, and several issues critical
to determining the scope of the evaluation performed.
A. The Science on Which the Decisions Are Based
In 2007, EPA initiated its assessment of the science and other
technical information to use in addressing the endangerment and cause
or contribute issues before it under CAA section 202(a). This
scientific and technical information was developed in the form of a TSD
in 2007. An earlier draft of this document was released as part of the
ANPR published July 30, 2008 (73 FR 44353). That earlier draft of the
TSD relied heavily on the IPCC Fourth Assessment Report of 2007, key
NRC reports, and a limited number of then-available synthesis and
assessment products of the U.S. Climate Change Science Program (CCSP;
now encompassed by USGCRP). EPA received a number of comments
specifically focused on the TSD during the 120-day public comment
period for the ANPR.
EPA revised and updated the TSD in preparing the Proposed Findings
on endangerment and cause or contribute. Many of the comments received
on the ANPR were reflected in the draft TSD released in April 2009 that
served as the underlying scientific and technical basis for the
Administrator's Proposed Findings, published April 24, 2009 (74 FR
18886). The draft TSD released in April 2009 also reflected the
findings of 11 new synthesis and assessment products under the U.S.
CCSP that had been published since July 2008.
The TSD that summarizes scientific findings from the major
assessments of the USGCRP, the IPCC, and the NRC accompanies these
Findings. The TSD is available at www.epa.gov/climatechange/endangerment.html and in the docket for this action. It also includes
the most recent comprehensive assessment of the USGCRP, Global Climate
Change Impacts in the United States,\8\ published in June 2009. In
addition, the TSD incorporates up-to-date observational data for a
number of key climate variables from the NOAA, and the most up-to-date
emissions data from EPA's annual Inventory of U.S. Greenhouse Gas
Emissions and Sinks, published in April, 2009.\9\ And finally, as
discussed in Section I.B of these Findings, EPA received a large number
of public comments on the Administrator's Proposed Findings, many of
which addressed science issues either generally or specifically as
reflected in the draft TSD released with the April 2009 proposal. A
number of edits and updates were made to the draft TSD as a result of
these comments.\10\
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\8\ Karl, T., J. Melillo, and T. Peterson (Eds.) (2009) Global
Climate Change Impacts in the United States. Cambridge University
Press, Cambridge, United Kingdom.
\9\ U.S. EPA (2009) Inventory of U.S. Greenhouse Gas Emissions
and Sinks: 1990-2007. EPA-430-R-09-004, Washington, DC.
\10\ EPA has placed within the docket a separate memo ``Summary
of Major Changes to the Technical Support Document'' identifying
where within the TSD such changes were made relative to the draft
TSD released in April 2009.
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EPA is giving careful consideration to all of the scientific and
technical information in the record, as discussed below. However, the
Administrator is relying on the major assessments of the USGCRP, IPCC,
and NRC as the primary scientific and technical basis of her
endangerment decision for a number of reasons.
First, these assessments address the scientific issues that the
Administrator must examine for the endangerment analysis. When viewed
in total, these assessments address the issue of greenhouse gas
endangerment by providing data and information on: (1) The amount of
greenhouse gases being emitted by human activities; (2) how greenhouse
gases have been and continue to accumulate in the atmosphere as a
result of human activities; (3) changes to the Earth's energy balance
as a result of the buildup of atmospheric greenhouse gases; (4)
observed temperature and other climatic changes at the global and
regional scales; (5) observed changes in other climate-sensitive
sectors and systems of the human and natural environment; (6) the
extent to which observed climate change and other changes in climate-
sensitive systems can be attributed to the human-induced buildup of
atmospheric greenhouse gases; (7) future projected climate change under
a range of different scenarios of changing greenhouse gas emission
rates; and (8) the projected risks and impacts to
[[Page 66511]]
human health, society and the environment.
Second, as indicated above, these assessments are recent and
represent the current state of knowledge on the key elements for the
endangerment analysis. It is worth noting that the June 2009 assessment
of the USGCRP incorporates a number of key findings from the 2007 IPCC
Fourth Assessment Report; such findings include the attribution of
observed climate change to human emissions of greenhouse gases, and the
future projected scenarios of climate change for the global and
regional scales. This demonstrates that much of the underlying science
that EPA has been utilizing since 2007 has not only been in the public
domain for some time, but also has remained relevant and robust.
Third, these assessments are comprehensive in their coverage of the
greenhouse gas and climate change problem, and address the different
stages of the emissions-to-potential-harm chain necessary for the
endangerment analysis. In so doing, they evaluate the findings of
numerous individual peer-reviewed studies in order to draw more general
and overarching conclusions about the state of science. The USGCRP,
IPCC, and NRC assessments synthesize literally thousands of individual
studies and convey the consensus conclusions on what the body of
scientific literature tells us.
Fourth, these assessment reports undergo a rigorous and exacting
standard of peer review by the expert community, as well as rigorous
levels of U.S. government review and acceptance. Individual studies
that appear in scientific journals, even if peer reviewed, do not go
through as many review stages, nor are they reviewed and commented on
by as many scientists. The review processes of the IPCC, USGCRP, and
NRC (explained in fuller detail in the TSD and the Response to Comments
document, Volume 1) provide EPA with strong assurance that this
material has been well vetted by both the climate change research
community and by the U.S. government. These assessments therefore
essentially represent the U.S. government's view of the state of
knowledge on greenhouse gases and climate change. For example, with
regard to government acceptance and approval of IPCC assessment
reports, the USGCRP Web site states that: ``When governments accept the
IPCC reports and approve their Summary for Policymakers, they
acknowledge the legitimacy of their scientific content.'' \11\ It is
the Administrator's view that such review and acceptance by the U.S.
Government lends further support for placing primary weight on these
major assessments.
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\11\ http://www.globalchange.gov/publications/reports/ipcc-reports.
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It is EPA's view that the scientific assessments of the IPCC,
USGRCP, and the NRC represent the best reference materials for
determining the general state of knowledge on the scientific and
technical issues before the agency in making an endangerment decision.
No other source of information provides such a comprehensive and in-
depth analysis across such a large body of scientific studies, adheres
to such a high and exacting standard of peer review, and synthesizes
the resulting consensus view of a large body of scientific experts
across the world. For these reasons, the Administrator is placing
primary and significant weight on these assessment reports in making
her decision on endangerment.
A number of commenters called upon EPA to perform a new and
independent assessment of all of the underlying climate change science,
separate and apart from USGCRP, IPCC, and NRC. In effect, commenters
suggest that EPA is either required to or should ignore the attributes
discussed above concerning these assessment reports, and should instead
perform its own assessment of all of the underlying studies and
information.
In addition to the significant reasons discussed above for relying
on and placing primary weight on these assessment reports, EPA has been
a very active part of the U.S. government climate change research
enterprise, and has taken an active part in the review, writing, and
approval of these assessments. EPA was the lead agency for three
significant reports under the USGCRP \12\, and recently completed an
assessment addressing the climate change impacts on U.S. air quality--a
report on which the TSD heavily relies for that particular issue. EPA
was also involved in review of the IPCC Fourth Assessment Report, and
in particular took part in the approval of the summary for policymakers
for the Working Group II Volume, Impacts, Adaptation and
Vulnerability.\13\ The USGCRP, IPCC, and NRC assessments have been
reviewed and formally accepted by, commissioned by, or in some cases
authored by, U.S. government agencies and individual government
scientists. These reports already reflect significant input from EPA's
scientists and the scientists of many other government agencies.
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\12\ CCSP (2009) Coastal Sensitivity to Sea-Level Rise: A Focus
on the Mid-Atlantic Region. A Report by the U.S. Climate Change
Science Program and the Subcommittee on Global Change Research.
[James G. Titus (Coordinating Lead Author), K. Eric Anderson, Donald
R. Cahoon, Dean B. Gesch, Stephen K. Gill, Benjamin T. Gutierrez, E.
Robert Thieler, and S. Jeffress Williams (Lead Authors)], U.S.
Environmental Protection Agency, Washington DC, USA, 320 pp. CCSP
(2008) Preliminary review of adaptation options for climate-
sensitive ecosystems and resources. A Report by the U.S. Climate
Change Science Program and the Subcommittee on Global Change
Research. [Julius, S.H., J.M. West (eds.), J.S. Baron, B. Griffith,
L.A. Joyce, P. Kareiva, B.D. Keller, M.A. Palmer, C.H. Peterson, and
J.M. Scott (Authors)]. U.S. Environmental Protection Agency,
Washington, DC, USA, 873 pp. CCSP (2008) Analyses of the effects of
global change on human health and welfare and human systems. A
Report by the U.S. Climate Change Science Program and the
Subcommittee on Global Change Research. [Gamble, J.L. (ed.), K.L.
Ebi, F.G. Sussman, T.J. Wilbanks, (Authors)]. U.S. Environmental
Protection Agency, Washington, DC, USA.
\13\ IPCC (2007) Climate Change 2007: Impacts, Adaptation and
Vulnerability. Contribution of Working Group II to the Fourth
Assessment Report of the Intergovernmental Panel on Climate Change,
M.L. Parry, O.F. Canziani, J.P. Palutikof, P.J. van der Linden and
C.E. Hanson, Eds., Cambridge University Press, Cambridge, UK, 976pp.
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EPA has no reason to believe that the assessment reports do not
represent the best source material to determine the state of science
and the consensus view of the world's scientific experts on the issues
central to making an endangerment decision with respect to greenhouse
gases. EPA also has no reason to believe that putting this significant
body of work aside and attempting to develop a new and separate
assessment would provide any better basis for making the endangerment
decision, especially because any such new assessment by EPA would still
have to give proper weight to these same consensus assessment reports.
In summary, EPA concludes that its reliance on existing and recent
synthesis and assessment reports is entirely reasonable and allows EPA
to rely on the best available science.\14\ EPA also recognizes that
scientific research is very active in many areas addressed in the TSD
(e.g., aerosol effects on climate, climate feedbacks such as water
vapor, and internal and external climate forcing mechanisms), as well
as for some emerging issues (e.g., ocean acidification and climate
change effects on water quality). EPA recognizes the potential
importance of new scientific research, and the value of an ongoing
process to take more recent science into account. EPA reviewed new
literature in
[[Page 66512]]
preparation of this TSD to evaluate its consistency with recent
scientific assessments. We also considered public comments received and
studies incorporated by reference. In a number of cases, the TSD was
updated based on such information to add context for assessment
literature findings, which includes supporting information and/or
qualifying statements. In other cases, material that was not
incorporated into the TSD is discussed within the Response to Comments
document.
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\14\ It maintains the highest level of adherence to Agency and
OMB guidelines for data and scientific integrity and transparency.
This is discussed in greater detail in EPA's Response to Comments
document.
---------------------------------------------------------------------------
EPA reviewed these individual studies that were not considered or
reflected in these major assessments to evaluate how they inform our
understanding of how greenhouse gas emissions affect climate change,
and how climate change may affect public health and welfare. Given the
very large body of studies reviewed and assessed in developing the
assessment reports, and the rigor and breadth of that review and
assessment, EPA placed limited weight on the much smaller number of
individual studies that were not considered or reflected in the major
assessments. EPA reviewed them largely to see if they would lead EPA to
change or place less weight on the judgments reflected in the
assessment report. While EPA recognizes that some studies are more
useful or informative than others, and gave each study it reviewed the
weight it was due, the overall conclusion EPA drew from its review of
studies submitted by commenters was that the studies did not change the
various conclusions or judgments EPA would draw based on the assessment
reports.
Many comments focus on the scientific and technical data underlying
the Proposed Findings, such as climate change science and greenhouse
gas emissions data. These comments cover a range of topics and are
summarized and responded to in the Response to Public Comments
document. The responses note those cases where a technical or
scientific comment resulted in an editorial or substantive change to
the TSD. The final TSD reflects all changes made as a result of public
comments.
B. The Law on Which the Decisions Are Based
In addition to grounding these determinations on the science, they
are also firmly grounded in EPA's legal authority. Section II of these
Findings provides an in-depth discussion of the legal framework for the
endangerment and cause or contribute decisions under CAA section
202(a), with additional discussion in Section II of the Proposed
Finding (74 FR 18886, 18890, April 24, 2009). A variety of important
legal issues are also discussed in Sections III, IV, and V of these
Findings, as well as in the Response to Comments document, Volume 11.
Section IV and V of these Findings explain the Administrator's
decisions, and how she exercised her judgment in making the
endangerment and contribution determinations, based on the entire
scientific record before her and the legal framework structuring her
decision making.
C. Adaptation and Mitigation
Following the language of CAA section 202(a), in which the
Administrator, in her judgment, must determine if greenhouse gases
constitute the air pollution that may be reasonably anticipated to
endanger public health or welfare, EPA evaluated, based primarily on
the scientific reports discussed above, how greenhouse gases and other
climate-relevant substances are affecting the atmosphere and climate,
and how these climate changes affect public health and welfare, now and
in the future. Consistent with EPA's scientific approach underlying the
Administrator's Proposed Findings, EPA did not undertake a separate
analysis to evaluate potential societal and policy responses to any
threat (i.e., the endangerment) that may exist due to anthropogenic
emissions of greenhouse gases. Risk reduction through adaptation and
greenhouse gas mitigation measures is of course a strong focal area of
scientists and policy makers, including EPA; however, EPA considers
adaptation and mitigation to be potential responses to endangerment,
and as such has determined that they are outside the scope of the
endangerment analysis.
The Administrator's position is not that adaptation will not occur
or cannot help protect public health and welfare from certain impacts
of climate change, as some commenters intimated. To the contrary, EPA
recognizes that some level of autonomous adaptation \15\ will occur,
and commenters are correct that autonomous adaptation can affect the
severity of climate change impacts. Indeed, there are some cases in the
TSD in which some degree of adaptation is accounted for; these cases
occur where the literature on which the TSD relies already uses
assumptions about autonomous adaptation when projecting the future
effects of climate change. Such cases are noted in the TSD. We also
view planned adaptation as an important near-term risk-minimizing
strategy given that some degree of climate change will continue to
occur as a result of past and current emissions of greenhouse gases
that remain in the atmosphere for decades to centuries.
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\15\ The IPCC definition of adaptation: ``Adaptation to climate
change takes place through adjustments to reduce vulnerability or
enhance resilience in response to observed or expected changes in
climate and associated extreme weather events. Adaptation occurs in
physical, ecological and human systems. It involves changes in
social and environmental processes, perceptions of climate risk,
practices and functions to reduce potential damages or to realize
new opportunities.'' The IPCC defines autonomous adaptation as
``Adaptation that does not constitute a conscious response to
climatic stimuli but is triggered by ecological changes in natural
systems and by market or welfare changes in human systems.''
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However, it is the Administrator's position that projections of
adaptation and mitigation in response to risks and impacts associated
with climate change are not appropriate for EPA to consider in making a
decision on whether the air pollution endangers. The issue before EPA
involves evaluating the risks to public health and welfare from the air
pollution if we do not take action to address it. Adaptation and
mitigation address an important but different issue--how much risk will
remain assuming some projection of how people and society will respond
to the threat.
Several commenters argue that it is arbitrary not to consider
adaptation in determining endangerment. They contend that because
endangerment is a forward-looking exercise, the fundamental inquiry
concerns the type and extent of harm that is believed likely to occur
in the future. Just as the Administrator makes projections of potential
harms in the future, these commenters contend that the Administrator
needs to consider the literature on adaptation that addresses the
likelihood and the severity of potential effects. Commenters also note
that since adaption is one of the likely impacts of climate change, it
is irrational to exclude it from consideration when the goal is to
evaluate the risks and harms in the real world in the future, not the
risks and harms in the hypothetical scenario that result if you ignore
adaptation.
According to commenters, the Administrator must consider both
autonomous adaptation and anticipatory adaptation. They contend that
literature on adaptation makes it clear there is a significant
potential for adaptation, and that it can reduce the likelihood or
severity of various effects, including health effects, and could even
avert what might otherwise constitute endangerment. Commenters note
that EPA considered the adaptation of species in nature, and it is
arbitrary to not also consider adaptation by humans. Moreover, they
argue that there is great
[[Page 66513]]
certainty that adaptation will occur, and thus EPA is required to
address it and make projections. They recommend that EPA look to
historic responses to changes in conditions as an analogue in making
projections, recognizing that life in the United States is likely to be
quite different 50 or 100 years from now, irrespective of climate
change.
Commenters argue that adaption needs to be considered because it is
central to the statutory requirements governing the endangerment
inquiry. EPA is charged to determine the type and extent of harms that
are likely to occur, and they argue that this can not rationally be
considered without considering adaptation. Since some degree of
adaptation is likely to occur, they continue that such a projection of
future actual conditions requires consideration of adaption to evaluate
whether the future conditions amount to endangerment from the air
pollution.
According to commenters, the issue therefore is focused on human
and societal adaptation, which can come in a wide variety of forms,
ranging from changes in personal behavioral patterns to expenditures of
resources to change infrastructure, such as building and maintaining
barriers to protect against sea level rise.
With regard to mitigation, commenters argue that EPA should
consider mitigation strategies and their potential to alleviate harm
from greenhouse gas emissions. They contend that it is unreasonable for
EPA to assume that society will not undertake mitigation.
Section 202(a) of the CAA reflects the basic approach of many CAA
sections--the threshold inquiry is whether the endangerment and cause
or contribute criteria are satisfied, and only if they are met do the
criteria for regulatory action go into effect. This reflects the basic
separation of two different decisions--is this a health and welfare
problem that should be addressed, and if so what are the appropriate
mechanisms to address it? There is a division between identifying the
health and welfare problem associated with the air pollution, and
identifying the mechanisms used to address or solve the problem.
In evaluating endangerment, EPA is determining whether the risks to
health and welfare from the air pollution amount to endangerment. As
commenters recognize, that calls for evaluating and projecting the
nature and types of risks from the air pollution, including the
probability or likelihood of the occurrence of an impact and the degree
of adversity (or benefit) of such an impact. This issue focuses on how
EPA makes such an evaluation in determining endangerment--does EPA look
at the risks assuming no planned adaptation and/or mitigation, although
EPA projects some degree is likely to occur, or does EPA look at the
risks remaining after some projection of adaptation and/or mitigation?
These two approaches reflect different views of the core question
EPA is trying to answer. The first approach most clearly focuses on
just the air pollution and its impacts, and aims to separate this from
the human and societal responses that may or should be taken in
response to the risks from the air pollution. By its nature, this
separation means this approach may not reflect the actual conditions in
the real world in the future, because adaptation and/or mitigation may
occur and change the risks. For example, adaptation would not change
the atmospheric concentrations, or the likelihood or probability of
various impacts occurring (e.g., it would not change the degree of sea
level rise), but adaptation has the potential to reduce the adversity
of the effects that do occur from these impacts. Mitigation could
reduce the atmospheric concentrations that would otherwise occur,
having the potential to reduce the likelihood or probability of various
impacts occurring. Under this approach, the evaluation of risk is
focused on the risk if we do not address the problem. It does not
answer the question of how much risk we project will remain after we do
address the problem, through either adaptation or mitigation or some
combination of the two.
The second approach, suggested by commenters, would call for EPA to
project into the future adaptation and/or mitigation, and the effect of
these measures in reducing the risks to health or welfare from the air
pollution. Commenters argue this will better reflect likely real world
conditions, and therefore is needed to allow for an appropriate
determination of whether EPA should, at this time, make an affirmative
endangerment finding. However, this approach would not separate the air
pollution and its impacts from the human and societal responses to the
air pollution. It would intentionally and inextricably intertwine them.
It would inexorably change the focus from how serious is the air
pollution problem we need to address to how good a job are people and
society likely to do in addressing or solving the problem. In addition
it would dramatically increase the complexity of the issues before EPA.
The context for this endangerment finding is a time span of several
decades into the future. It involves a wide variety of differing health
and welfare effects, and almost every sector in our society. This
somewhat unique context tends to amplify the differences between the
two different approaches. It also means that it is hard to cleanly
implement either approach. For example, it is hard under the first
approach to clearly separate impacts with and without adaption, given
the nature of the scientific studies and information before us. Under
the second approach it would be extremely hard to make a reasoned
projection of human and societal adaptation and mitigation responses,
because these are basically not scientific or technical judgments, but
are largely political judgments for society or individual personal
judgments.
However, the context for this endangerment finding does not change
the fact that at their core the two different approaches are aimed at
answering different questions. The first approach is focused on
answering the question of what are the risks to public health and
welfare from the air pollution if we do not take action to address it.
The second approach is focused on answering the question of how much
risk will remain assuming some projection of how people and society
will respond.
EPA believes that it is appropriate and reasonable to interpret CAA
section 202(a) as calling for the first approach. The structure of CAA
section 202(a) and the various other similar provisions indicate an
intention by Congress to separate the question of what is the problem
we need to address from the question of what is the appropriate way to
address it. The first approach is clearly more consistent with this
statutory structure. The amount of reduction in risk that might be
achieved through adaptation and/or mitigation is closely related to the
way to address a problem, and is not focused on what is the problem
that needs to be addressed. It helps gauge the likelihood of success in
addressing a problem, and how good a job society may do in reducing
risk; it is not at all as useful in determining the severity of the
problem that needs to be addressed.
The endangerment issue at its core is a decision on whether there
is a risk to health and welfare that needs to be addressed, and the
second approach would tend to indicate that the more likely a society
is to solve a problem, the less likely there is a problem that needs to
be addressed. This would mask the issue and provide a directionally
wrong signal. Assume two different situations, both presenting the same
serious risks to
[[Page 66514]]
public health or welfare without consideration of adaptation or
mitigation. The more successful society is projected to be in solving
the serious problem in the future would mean the less likely we would
be to make an endangerment finding at the inception identifying it as a
problem that needs to be addressed. This is much less consistent with
the logic embodied in CAA section 202(a), which separates the issue of
whether there is a problem from the issue of what can be done to
successfully address it.
In addition, the second approach would dramatically increase the
complexity of the issues to resolve, and would do this by bringing in
issues that are not the subject of the kind of scientific or technical
judgments that Congress envisioned for the endangerment test. The
legislative history indicates Congress was focused on issues of science
and medicine, including issues at the frontiers of these fields. It
referred to data, research resources, science and medicine, chemistry,
biology, and statistics. There is no indication Congress envisioned
exercising judgment on the very different types of issues involved in
projecting the political actions likely to be taken by various local,
State, and Federal governments, or judgments on the business or other
decisions that are likely to be made by companies or other
organizations, or the changes in personal behavior that may be
occasioned by the adverse impacts of air pollution. The second approach
would take EPA far away from the kind of judgments Congress envisioned
for the endangerment test.
D. Geographic Scope of Impacts
It is the Administrator's view that the primary focus of the
vulnerability, risk, and impact assessment is the United States. As
described in Section IV of these Findings, the Administrator gives some
consideration to climate change effects in world regions outside of the
United States. Given the global nature of climate change, she has also
examined potential impacts in other regions of the world. Greenhouse
gases, once emitted, become well mixed in the atmosphere, meaning U.S.
emissions can affect not only the U.S. population and environment, but
other regions of the world as well. Likewise, emissions in other
countries can affect the United States. Furthermore, impacts in other
regions of the world may have consequences that in turn raise
humanitarian, trade, and national security concerns for the United
States.
Commenters argue that EPA does not have the authority to consider
international effects. They contend that the burden is on EPA is to
show endangerment based on impacts in the United States. They note that
EPA proposed this approach, which is the only relevant issue for EPA.
The purpose of CAA section 202(a), as the stated purpose of the CAA,
commenters note, is to protect the quality of the nation's air
resources and to protect the health and welfare of the U.S. population.
Thus, they continue, international public health and welfare are not
listed or stated, and are not encompassed by these provisions.
Moreover, they argue that Congress addressed international impacts
expressly in two other provisions of the CAA. They note that under CAA
section 115, EPA considers emissions of pollutants that cause or
contribute to air pollution that is reasonably anticipated to endanger
public health or welfare in a foreign country, and that CAA section
179B addresses emissions of air pollutants in foreign countries that
interfere with attainment of a National Ambient Air Quality Standards
(NAAQS) in the United States. Because Congress intentionally addressed
international impacts in those provision, commenters argue that the
absence of this direction in CAA section 202(a) means that EPA is not
to consider international effects when assessing endangerment under
this provision.
Commenters fail to recognize that EPA's consideration of
international effects is directed at evaluating their impact on the
public health and welfare of the U.S. population. EPA is not
considering international effects to determine whether the health and
welfare of the public in a foreign country is endangered. Instead,
EPA's consideration of international effects for purposes of
determining endangerment is limited to how those international effects
impact the health and welfare of the U.S. population.
The Administrator looked first at impacts in the United States
itself, and determined that these impacts are reasonably anticipated to
endanger the public health and the welfare of the U.S. population. That
remains the Administrator's position, and by itself supports her
determination of endangerment. The Administrator also considered the
effects of global climate change outside the borders of the United
States and evaluated them to determine whether these international
effects impact the U.S. population, and if so whether it impacts the
U.S. population in a manner that supports or does not support
endangerment to the health and welfare of the U.S. public. She is not
evaluating international effects to determine whether populations in a
foreign country are endangered. The Administrator is looking at
international effects solely for the purpose of evaluating their
effects on the U.S. population.
For example, the U.S. population can be impacted by effects in
other countries. These international effects can impact U.S. economic,
trade, and humanitarian and national security interests. These would be
potential effects on the U.S. population, brought about by the effects
of climate change occurring outside the United States. It is fully
reasonable and rational to expect that events occurring outside our
borders can affect the U.S. population.
Thus, commenters misunderstand the role that international effects
played in the proposal. The Administrator is not evaluating the impact
of international effects on populations outside the United States; she
is considering what impact these international effects could have on
the U.S. population. That is fully consistent with the CAA's stated
purpose of protecting the health and welfare of this nation's
population.
E. Temporal Scope of Impacts
An additional parameter of the endangerment analysis is the
timeframe. The Administrator's view is that the timeframe over which
vulnerabilities, risks, and impacts are considered should be consistent
with the timeframe over which greenhouse gases, once emitted, have an
effect on climate. Thus the relevant time frame is decades to centuries
for the primary greenhouse gases of concern. Therefore, in addition to
reviewing recent observations, the underlying science upon which the
Administrator is basing her findings generally considers the next
several decades--the time period out to around 2100, and for certain
impacts, the time period beyond 2100. How the accumulation of
atmospheric greenhouse gases and resultant climate change may affect
current and future generations is discussed in section IV in these
Findings. By current generations we mean a near-term time frame of
approximately the next 10 to 20 years; by future generations we mean a
longer-term time frame extending beyond that. Some public comments were
received that questioned making an endangerment finding based on
current conditions, while others questioned EPA's ability to make an
endangerment finding based on future projected conditions. Some of
these comments are likewise addressed in Section IV in these Findings;
and all comments on these temporal issues are addressed in the Response
to Comments document.
[[Page 66515]]
F. Impacts of Potential Future Regulations and Processes That Generate
Greenhouse Gas Emissions
This action is a stand-alone set of findings regarding endangerment
and cause or contribute for greenhouse gases under CAA section 202(a),
and does not contain any regulatory requirements. Therefore, this
action does not attempt to assess the impacts of any future regulation.
Although EPA would evaluate any future proposed regulation, many
commenters argue that such a regulatory analysis should be part of the
endangerment analysis.
Numerous commenters argue that EPA must fully consider the adverse
and beneficial impacts of regulation together with the impacts of
inaction, and describe this balancing as ``risk-risk analysis,''
``health-health analysis,'' and most predominantly ``risk tradeoff
analysis.'' Commenters argue that EPA's final endangerment finding
would be arbitrary unless EPA undertakes this type of risk trade-off
analysis.
Commenters specifically argue that EPA must consider the economic
impact of regulation, including the Prevention of Significant
Deterioration (PSD) permitting program for major stationary sources
because it is triggered by a CAA section 202(a) standard, when
assessing whether there is endangerment to public welfare. In other
words, they argue that the Administrator should determine if finding
endangerment and regulating greenhouse gases under the CAA would be
worse for public health and welfare than not regulating. Commenters
also argue that the reference to ``public'' health or welfare in CAA
section 202, as well as the fact that impacts on the economy should be
considered impacts to welfare, especially requires EPA to consider the
full range of possible impacts of regulation. Commenters provide
various predictions regarding how regulating greenhouse gases under the
CAA more broadly will impact the public, industry, states the overall
economy, and thus, they conclude, public health and welfare. Examples
of commenters' predictions include potential adverse impacts on (1) the
housing industry and the availability of affordable housing, (2) jobs
and income due to industry moving overseas, (3) the agriculture
industry and its ability to provide affordable food, and (4) the
nation's energy supply. They also cite to the letter from the Office of
Management and Budget provided with the ANPR, as well as interagency
comments on the draft Proposed Findings, in support of their argument.
At least one commenter argues that EPA fails to discuss the public
health or welfare benefits of the processes that produce the emissions.
The commenter contends that for purposes of CAA section 202(a), this
process would be the combustion of gasoline or other transportation
fuel in new motor vehicles, and that for purposes of other CAA
provisions with similar endangerment finding triggers, the processes
would be the combustion of fossil fuel for electric generation and
other activities. The commenter continues that EPA's decision to limit
its analysis to the perceived detrimental aspects of emissions after
they enter the atmosphere--as opposed to the possible positive aspects
of emissions because of the processes that create the emissions--is
based on EPA's overly narrow interpretation of both the meaning of the
term ``emission'' in CAA section 202(a) (and therefore in other
endangerment finding provisions) and the intent of these provisions.
The commenter states that logically, it makes little sense to limit the
definition of the term ``emission'' to only the ``air pollutants'' that
are emitted. The commenter concludes that when EPA assesses whether the
emission of greenhouse gases endanger public health and welfare, EPA
must assess the dangers and benefits on both sides of the point where
the emissions occur: in the atmosphere where the emissions lodge and,
on the other side of the emitting stack or structure, in the processes
that create the emissions. Otherwise, EPA will not be able to
accurately assess whether the fact that society emits greenhouse gases
is a benefit or a detriment. The commenter states that because
greenhouse gas emissions, particularly carbon dioxide emissions, are so
closely tied with all facets of modern life, a finding that greenhouse
gas emissions endanger public health and welfare is akin to saying that
modern life endangers public health or welfare. The commenter states
that simply cannot be true because the lack of industrial activity that
causes greenhouse gas emissions would pose other, almost certainly more
serious health and welfare consequences.
Finally, some commenters argue that the impact of regulating under
CAA section 202(a) supports making a final, negative endangerment
finding. These commenters contend that the incredible costs associated
with using the inflexible regulatory structure of the CAA will harm
public health and welfare, and therefore EPA should exercise its
discretion and find that greenhouse gases do not endanger public health
and welfare because once EPA makes an endangerment finding under CAA
section 202(a), it will be forced to regulate greenhouse gases under a
number of other sections of the CAA, resulting in regulatory chaos.
At their core, these comments are not about whether commenters
believe greenhouse gases may reasonably be anticipated to endanger
public health or welfare, but rather about commenters' dissatisfaction
with the decisions that Congress made regarding the response to any
endangerment finding that EPA makes under CAA section 202(a). These
comments do not discuss the science of greenhouse gases or climate
change, or the impacts of climate change on public health or welfare.
Instead they muddle the rather straightforward scientific judgment
about whether there may be endangerment by throwing the potential
impact of responding to the danger into the initial question. To use an
analogy, the question of whether the cure is worse than the illness is
different than the question of whether there is an illness in the first
place. The question of whether there is endangerment is like the
question of whether there is an illness. Once one knows there is an
illness, then the next question is what to do, if anything, in response
to that illness.
What these comments object to is that Congress has already made
some decisions about next steps after a finding of endangerment, and
commenters are displeased with the results. But if this is the case,
commenters should take up their concerns with Congress, not EPA. EPA's
charge is to issue new motor vehicle standards under CAA section 202(a)
applicable to emissions of air pollutants that cause or contribute to
air pollution which may reasonably be anticipated to endanger public
health or welfare. It is not to find that there is no endangerment in
order to avoid issuing those standards, and dealing with any additional
regulatory impact.
Indeed, commenters' argument would insert policy considerations
into the endangerment decision, an approach already rejected by the
Supreme Court. First, as discussed in Section I.B of these Findings, in
Massachusetts v. EPA, the court clearly indicated that the
Administrator's decision must be a ``scientific judgment.'' 549 U.S. at
534. She must base her decision about endangerment on the science, and
not on policy considerations about the repercussions or impact of such
a finding.
Second, in considering whether the CAA allowed for economic
considerations to play a role in the promulgation of the NAAQS, the
[[Page 66516]]
Supreme Court rejected arguments that because many more factors than
air pollution might affect public health, EPA should consider
compliance costs that produce health losses in setting the NAAQS.
Whitman v. ATA, 531 U.S. at 457, 466 (2001). To be sure, the language
in CAA section 109(b) applicable to the setting of a NAAQS is different
than that in CAA section 202(a) regarding endangerment. But the
concepts are similar--the NAAQS are about setting standards at a level
requisite to protect public health (with an adequate margin of safety)
and public welfare, and endangerment is about whether the current or
projected future levels may reasonably be anticipated to endanger
public health or welfare. In other words, both decisions essentially
are based on assessing the harm associated with a certain level of air
pollution.
Given this similarity in purpose, as well as the Court's
instructions in Massachusetts v. EPA that the Administrator should base
her decision on the science, EPA reasonably interprets the statutory
endangerment language to be analogous to setting the NAAQS. Therefore,
it is reasonable to interpret the endangerment test as not requiring
the consideration of the impacts of implementing the statute in the
event of an endangerment finding as part of the endangerment finding
itself.\16\
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\16\ Indeed, some persons may argue that due to the similarities
between setting a NAAQS and making an endangerment finding, EPA
cannot consider the impacts of implementation of the statute.
---------------------------------------------------------------------------
Moreover, EPA does not believe that the impact of regulation under
the CAA as a whole, let alone that which will result from this
particular endangerment finding, will lead to the panoply of adverse
consequences that commenters predict. EPA has the ability to fashion a
reasonable and common-sense approach to address greenhouse gas
emissions and climate change. The Administrator thinks that EPA has and
will continue to take a measured approach to address greenhouse gas
emissions. For example, the Agency's recent Mandatory Greenhouse Gas
Reporting Rule focuses on only the largest sources of greenhouse gases
in order to reduce the burden on smaller facilities.\17\
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\17\ Note that it is EPA's current position that these Final
Findings do not make well-mixed greenhouse gases ``subject to
regulation'' for purposes of the CAA's Prevention of Significant
Deterioration (PSD) and title V programs. See, e.g., memorandum
entitled ``EPA's Interpretation of Regulations that Determine
Pollutants Covered By Federal Prevention of Significant
Deterioration (PSD) Permit Program'' (Dec. 18, 2008). While EPA is
reconsidering this memorandum and is seeking public comment on the
issues raised in it generally, including whether a final
endangerment finding should trigger PSD, the effectiveness of the
positions provided in the memorandum was not stayed pending that
reconsideration. Prevention of Significant Deterioration (PSD):
Reconsideration of Interpretation of Regulations That Determine
Pollutants Covered by the Federal PSD Permit Program, 74 FR 515135,
51543-44 (Oct. 7, 2009). In addition, EPA has proposed new temporary
thresholds for greenhouse gas emissions that define when PSD and
title V permits are required for new or existing facilities.
Prevention of Significant Deterioration and Title V Greenhouse Gas
Tailoring Rule (74 FR 55292, October 27, 2009). The proposed
thresholds would ``tailor'' the permit programs to limit which
facilities would be required to obtain PSD and title V permits. As
noted in the preamble for the tailoring rule proposal, EPA also
intends to evaluate ways to streamline the process for identifying
GHG emissions control requirements and issuing permits. See the
Response to Comments Document, Volume 11, and the Tailoring Rule,
for more information.
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We also note that commenters' approach also is another version of
the argument that EPA must consider adaptation and mitigation in the
endangerment determination. Just as EPA should consider whether
mitigation would reduce endangerment, commenters argue we should
consider whether mitigation would increase endangerment. But as
discussed previously, EPA disagrees and believes its approach better
achieves the goals of the statute.
Finally, EPA simply disagrees with the commenter who argues that
because we are better off now than before the industrial revolution,
greenhouse gases cannot be found to endanger public health or welfare.
As the DC Circuit noted in the Ethyl decision, ``[m]an's ability to
alter his environment has developed far more rapidly than his ability
to foresee with certainty the effects of his alterations.'' See Ethyl
Corp., 541 F.2d at 6. The fact that we as a society are better off now
than 100 years ago, and that processes that produce greenhouse gases
are a large part of this improvement, does not mean that those
processes do not have unintended adverse impacts. It also was entirely
reasonable for EPA to look at ``emissions'' as the pollution once it is
emitted from the source into the air, and not also as the process that
generates the pollution. Indeed, the definition of ``air pollutant''
talks in terms of substances ``emitted into or otherwise enter[ing] the
ambient air'' (CAA section 302(g)). It is entirely appropriate for EPA
to consider only the substance being emitted as the air pollution or
air pollutant.
IV. The Administrator's Finding That Greenhouse Gases Endanger Public
Health and Welfare
The Administrator finds that elevated concentrations of greenhouse
gases in the atmosphere may reasonably be anticipated to endanger the
public health and to endanger the public welfare of current and future
generations. The Administrator is making this finding specifically with
regard to six key directly-emitted, long-lived and well-mixed
greenhouse gases: Carbon dioxide, methane, nitrous oxide,
hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride. The
Administrator is making this judgment based on both current
observations and projected risks and impacts into the future.
Furthermore, the Administrator is basing this finding on impacts of
climate change within the United States. However, the Administrator
finds that when she considers the impacts on the U.S. population of
risks and impacts occurring in other world regions, the case for
endangerment to public health and welfare is only strengthened.
A. The Air Pollution Consists of Six Key Greenhouse Gases
The Administrator must define the scope and nature of the relevant
air pollution for the endangerment finding under CAA section 202(a). In
this final action, the Administrator finds that the air pollution is
the combined mix of six key directly-emitted, long-lived and well-mixed
greenhouse gases (henceforth ``well-mixed greenhouse gases''), which
together, constitute the root cause of human-induced climate change and
the resulting impacts on public health and welfare. These six
greenhouse gases are carbon dioxide, methane, nitrous oxide,
hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride.
EPA received public comments on this definition of air pollution
from the Proposed Findings, and summarizes responses to some of those
key comments below; fuller responses to public comments can be found in
EPA's Response to Comments document, Volume 9. The Administrator
acknowledges that other anthropogenic climate forcers also play a role
in climate change. Many public comments either supported or opposed
inclusion of other substances in addition to the six greenhouse gases
for the definition of air pollution. EPA's responses to those comments
are also summarized below, and in volume 9 of the Response to Comments
document.
The Administrator explained her rationale for defining air
pollution under CAA section 202(a) as the combined mix of the six
greenhouse gases in the Proposed Findings. After review of the public
comments, the Administrator is using the same definition of the air
pollution in the
[[Page 66517]]
final finding, for the following reasons: (1) These six greenhouse gas
share common properties regarding their climate effects; (2) these six
greenhouse gases have been estimated to be the primary cause of human-
induced climate change, are the best understood drivers of climate
change, and are expected to remain the key driver of future climate
change; (3) these six greenhouse gases are the common focus of climate
change science research and policy analyses and discussions; (4) using
the combined mix of these gases as the definition (versus an individual
gas-by-gas approach) is consistent with the science, because risks and
impacts associated with greenhouse gas-induced climate change are not
assessed on an individual gas approach; and (5) using the combined mix
of these gases is consistent with past EPA practice, where separate
substances from different sources, but with common properties, may be
treated as a class (e.g., oxides of nitrogen).
1. Common Physical Properties of the Six Greenhouse Gases
The common physical properties relevant to the climate change
problem shared by the six greenhouse gases include the fact that they
are long-lived in the atmosphere. ``Long-lived'' is used here to mean
that the gas has a lifetime in the atmosphere sufficient to become
globally well mixed throughout the entire atmosphere, which requires a
minimum atmospheric lifetime of about one year.\18\ Thus, this
definition of air pollution is global in nature because the greenhouse
gas emissions emitted from the United States (or from any other region
of the world) become globally well mixed, such that it would not be
meaningful to define the air pollution as the greenhouse gas
concentrations over the United States as somehow being distinct from
the greenhouse gas concentrations over other regions of the world.
---------------------------------------------------------------------------
\18\ The IPCC also refers to these six GHGs as long-lived.
Methane has an atmospheric lifetime of roughly a decade. One of the
most commonly used hydrofluorocarbons (HFC-134a) has a lifetime of
14 years. Nitrous oxide has a lifetime of 114 years; sulfur
hexafluoride over 3,000 years; and some PFCs up to 10,000 to 50,000
years. Carbon dioxide in the atmosphere is sometimes approximated as
having a lifetime of roughly 100 years, but for a given amount of
carbon dioxide emitted a better description is that some fraction of
the atmospheric increase in concentration is quickly absorbed by the
oceans and terrestrial vegetation, some fraction of the atmospheric
increase will only slowly decrease over a number of years, and a
small portion of the increase will remain for many centuries or
more.
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It is also well established that each of these gases can exert a
warming effect on the climate by trapping in heat that would otherwise
escape to space. These six gases are directly emitted as greenhouse
gases rather than forming as a greenhouse gas in the atmosphere after
emission of a pre-cursor gas. Given these properties, the magnitude of
the warming effect of each of these gases is generally better
understood than other climate forcing agents that do not share these
same properties (addressed in more detail below). The ozone-depleting
substances that include chlorofluorocarbons (CFCs) and
hydrochlorofluorocarbons (HFCs) also share the same physical attributes
discussed here, but for reasons discussed throughout the remainder of
this section are not being included in the Administrator's definition
of air pollution for this finding.
2. Evidence That the Six Greenhouse Gases Are the Primary Driver of
Current and Projected Climate Change
a. Key Observations Driven Primarily by the Six Greenhouse Gases
The latest assessment of the USGCRP, as summarized in EPA's TSD,
confirms the evidence presented in the Proposed Findings that current
atmospheric greenhouse gas concentrations are now at elevated and
essentially unprecedented levels as a result of both historic and
current anthropogenic emissions. The global atmospheric carbon dioxide
concentration has increased about 38 percent from pre-industrial levels
to 2009, and almost all of the increase is due to anthropogenic
emissions. The global atmospheric concentration of methane has
increased by 149 percent since pre-industrial levels (through 2007);
and the nitrous oxide concentration has increased 23 percent (through
2007). The observed concentration increase in these gases can also be
attributed primarily to anthropogenic emissions. The industrial
fluorinated gases have relatively low concentrations, but these
concentrations have also been increasing and are almost entirely
anthropogenic in origin.
Historic data show that current atmospheric concentrations of the
two most important directly emitted, long-lived greenhouse gases
(carbon dioxide and methane) are well above the natural range of
atmospheric concentrations compared to at least the last 650,000 years.
Atmospheric greenhouse gas concentrations have been increasing because
anthropogenic emissions are outpacing the rate at which greenhouse
gases are removed from the atmosphere by natural processes over
timescales of decades to centuries. It also remains clear that these
high atmospheric concentrations of greenhouse gases are the unambiguous
result of human activities.
Together the six well-mixed greenhouse gases constitute the largest
anthropogenic driver of climate change.\19\ Of the total anthropogenic
heating effect caused by the accumulation of the six well-mixed
greenhouse gases plus other warming agents (that do not meet all of the
Administrator's criteria that pertain to the six greenhouse gases)
since pre-industrial times, the combined heating effect of the six
well-mixed greenhouses is responsible for roughly 75 percent, and it is
expected that this share may grow larger over time, as discussed below.
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\19\ As summarized in EPA's TSD, the global average net effect
of the increase in atmospheric greenhouse gas concentrations, plus
other human activities (e.g., land use change and aerosol
emissions), on the global energy balance since 1750 has been one of
warming. This total net heating effect, referred to as forcing, is
estimated to be +1.6 (+0.6 to +2.4) Watts per square meter (W/
m2), with much of the range surrounding this estimate due
to uncertainties about the cooling and warming effects of aerosols.
The combined radiative forcing due to the cumulative (i.e., 1750 to
2005) increase in atmospheric concentrations of CO2,
CH4, and N2O is estimated to be +2.30 (+2.07
to +2.53) W/m2. The rate of increase in positive
radiative forcing due to these three GHGs during the industrial era
is very likely to have been unprecedented in more than 10,000 years.
---------------------------------------------------------------------------
Warming of the climate system is unequivocal, as is now evident
from observations of increases in global average air and ocean
temperatures, widespread melting of snow and ice, and rising global
average sea level. Global mean surface temperatures have risen by 0.74
[deg]C (1.3 [deg]F) (0.18 [deg]C) over the last 100 years.
Eight of the 10 warmest years on record have occurred since 2001.
Global mean surface temperature was higher during the last few decades
of the 20th century than during any comparable period during the
preceding four centuries.
The global surface temperature record relies on three major global
temperature datasets, developed by NOAA, NASA, and the United Kingdom's
Hadley Center. All three show an unambiguous warming trend over the
last 100 years, with the greatest warming occurring over the past 30
years.\20\ Furthermore, all three datasets show that eight of the 10
warmest years on record have occurred since 2001; that the 10 warmest
years have all occurred in the past 12 years; and that the 20 warmest
years have all occurred since 1981. Though most of the warmest years on
record have occurred in the last decade in all available datasets, the
rate of warming has, for a short time in the
[[Page 66518]]
Hadley Center record, slowed. However, the NOAA and NASA trends do not
show the same marked slowdown for the 1999-2008 period. Year-to-year
fluctuations in natural weather and climate patterns can produce a
period that does not follow the long-term trend. Thus, each year may
not necessarily be warmer than every year before it, though the long-
term warming trend continues.\21\
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\20\ See section 4 of the TSD for more detailed information
about the three global temperature datasets.
\21\ Karl T. et al., (2009).
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The scientific evidence is compelling that elevated concentrations
of heat-trapping greenhouse gases are the root cause of recently
observed climate change. The IPCC conclusion from 2007 has been re-
confirmed by the June 2009 USGCRP assessment that most of the observed
increase in global average temperatures since the mid-20th century is
very likely \22\ due to the observed increase in anthropogenic
greenhouse gas concentrations. Climate model simulations suggest
natural forcing alone (e.g., changes in solar irradiance) cannot
explain the observed warming.
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\22\ The IPCC Fourth Assessment Report uses specific terminology
to convey likelihood and confidence. Likelihood refers to a
probability that the statement is correct or that something will
occur. ``Virtually certain'' conveys greater than 99 percent
probability of occurrence; ``very likely'' 90 to 99 percent;
``likely'' 66 to 90 percent. IPCC assigns confidence levels as to
the correctness of a statement. ``Very high confidence'' conveys at
least 9 out of 10 chance of being correct; ``high confidence'' about
8 out of 10 chance; ``medium confidence'' about 5 out of 10 chance.
The USGCRP uses the same or similar terminology in its reports. See
also Box 1.2 of the TSD. Throughout this document, this terminology
is used in conjunction with statements from the IPCC and USGCRP
reports to convey the same meaning that those reports intended. In
instances where a word such as ``likely'' may appear outside the
context of a specific IPCC or USGCRP statement, it is not meant to
necessarily convey the same quantitative meaning as the IPCC
terminology.
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The attribution of observed climate change to anthropogenic
activities is based on multiple lines of evidence. The first line of
evidence arises from our basic physical understanding of the effects of
changing concentrations of greenhouse gases, natural factors, and other
human impacts on the climate system. The second line of evidence arises
from indirect, historical estimates of past climate changes that
suggest that the changes in global surface temperature over the last
several decades are unusual.\23\ The third line of evidence arises from
the use of computer-based climate models to simulate the likely
patterns of response of the climate system to different forcing
mechanisms (both natural and anthropogenic).
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\23\ Karl T. et al. (2009).
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The claim that natural internal variability or known natural
external forcings can explain most (more than half) of the observed
global warming of the past 50 years is inconsistent with the vast
majority of the scientific literature, which has been synthesized in
several assessment reports. Based on analyses of widespread temperature
increases throughout the climate system and changes in other climate
variables, the IPCC has reached the following conclusions about
external climate forcing: ``It is extremely unlikely (<5 percent) that
the global pattern of warming during the past half century can be
explained without external forcing, and very unlikely that it is due to
known natural external causes alone'' (Hegerl et al., 2007). With
respect to internal variability, the IPCC reports the following: ``The
simultaneous increase in energy content of all the major components of
the climate system as well as the magnitude and pattern of warming
within and across the different components supports the conclusion that
the cause of the [20th century] warming is extremely unlikely (<5
percent) to be the result of internal processes'' (Hegerl et al.,
2007). As noted in the TSD, the observed warming can only be reproduced
with models that contain both natural and anthropogenic forcings, and
the warming of the past half century has taken place at a time when
known natural forcing factors alone (solar activity and volcanoes)
would likely have produced cooling, not warming.
United States temperatures also warmed during the 20th and into the
21st century; temperatures are now approximately 0.7 [deg]C (1.3
[deg]F) warmer than at the start of the 20th century, with an increased
rate of warming over the past 30 years. Both the IPCC and CCSP reports
attributed recent North American warming to elevated greenhouse gas
concentrations. The CCSP (2008g) report finds that for North America,
``more than half of this warming [for the period 1951-2006] is likely
the result of human-caused greenhouse gas forcing of climate change.''
Observations show that changes are occurring in the amount,
intensity, frequency, and type of precipitation. Over the contiguous
United States, total annual precipitation increased by 6.1 percent from
1901-2008. It is likely that there have been increases in the number of
heavy precipitation events within many land regions, even in those
where there has been a reduction in total precipitation amount,
consistent with a warming climate.
There is strong evidence that global sea level gradually rose in
the 20th century and is currently rising at an increased rate. It is
very likely that the response to anthropogenic forcing contributed to
sea level rise during the latter half of the 20th century. It is not
clear whether the increasing rate of sea level rise is a reflection of
short-term variability or an increase in the longer-term trend. Nearly
all of the Atlantic Ocean shows sea level rise during the last 50 years
with the rate of rise reaching a maximum (over 2 mm per year) in a band
along the U.S. east coast running east-northeast.
Satellite data since 1979 show that annual average Arctic sea ice
extent has shrunk by 4.1 percent per decade. The size and speed of
recent Arctic summer sea ice loss is highly anomalous relative to the
previous few thousands of years.
Widespread changes in extreme temperatures have been observed in
the last 50 years across all world regions including the United States.
Cold days, cold nights, and frost have become less frequent, while hot
days, hot nights, and heat waves have become more frequent.
Observational evidence from all continents and most oceans shows
that many natural systems are being affected by regional climate
changes, particularly temperature increases. However, directly
attributing specific regional changes in climate to emissions of
greenhouse gases from human activities is difficult, especially for
precipitation.
Ocean carbon dioxide uptake has lowered the average ocean pH
(increased the acidity) level by approximately 0.1 since 1750.
Consequences for marine ecosystems may include reduced calcification by
shell-forming organisms, and in the longer term, the dissolution of
carbonate sediments.
Observations show that climate change is currently affecting U.S.
physical and biological systems in significant ways. The consistency of
these observed changes in physical and biological systems and the
observed significant warming likely cannot be explained entirely due to
natural variability or other confounding non-climate factors.
b. Key Projections Based Primarily on Future Scenarios of the Six
Greenhouse Gases
There continues to be no reason to expect that, without substantial
and near-term efforts to significantly reduce emissions, atmospheric
levels of greenhouse gases will not continue to climb, and thus lead to
ever greater rates of climate change. Given the long atmospheric
lifetime of the six greenhouse gases, which range from roughly a decade
to centuries, future atmospheric greenhouse gas
[[Page 66519]]
concentrations for the remainder of this century and beyond will be
influenced not only by future emissions but indeed by present-day and
near-term emissions. Consideration of future plausible scenarios, and
how our current greenhouse gas emissions essentially commit present and
future generations to cope with an altered atmosphere and climate,
reinforces the Administrator's judgment that it is appropriate to
define the combination of the six key greenhouse gases as the air
pollution.
Most future scenarios that assume no explicit greenhouse gas
mitigation actions (beyond those already enacted) project increasing
global greenhouse gas emissions over the century, which in turn result
in climbing greenhouse gas concentrations. Under the range of future
emission scenarios evaluated by the assessment literature, carbon
dioxide is expected to remain the dominant anthropogenic greenhouse
gas, and thus driver of climate change, over the course of the 21st
century. In fact, carbon dioxide is projected to be the largest
contributor to total radiative forcing in all periods and the radiative
forcing associated with carbon dioxide is projected to be the fastest
growing. For the year 2030, projections of the six greenhouse gases
show an increase of 25 to 90 percent compared with 2000 emissions.
Concentrations of carbon dioxide and the other well-mixed gases
increase even for those scenarios where annual emissions toward the end
of the century are assumed to be lower than current annual emissions.
The radiative forcing associated with the non-carbon dioxide well-mixed
greenhouse gases is still important and increasing over time. Emissions
of the ozone-depleting substances are projected to continue decreasing
due to the phase-out schedule under the Montreal Protocol on Substances
that Deplete the Ozone Layer. Considerable uncertainties surround the
estimates and future projections of anthropogenic aerosols; future
atmospheric concentrations of aerosols, and thus their respective
heating or cooling effects, will depend much more on assumptions about
future emissions because of their short atmospheric lifetimes compared
to the six well-mixed greenhouse gases.
Future warming over the course of the 21st century, even under
scenarios of low emissions growth, is very likely to be greater than
observed warming over the past century. According to climate model
simulations summarized by the IPCC, through about 2030, the global
warming rate is affected little by the choice of different future
emission scenarios. By the end of the century, projected average global
warming (compared to average temperature around 1990) varies
significantly depending on emissions scenario and climate sensitivity
assumptions, ranging from 1.8 to 4.0 [deg]C (3.2 to 7.2 [deg]F), with
an uncertainty range of 1.1 to 6.4 [deg]C (2.0 to 11.5 [deg]F).
All of the United States is very likely to warm during this
century, and most areas of the United States are expected to warm by
more than the global average. The largest warming is projected to occur
in winter over northern parts of Alaska. In western, central and
eastern regions of North America, the projected warming has less
seasonal variation and is not as large, especially near the coast,
consistent with less warming over the oceans.
3. The Six Greenhouse Gases Are Currently the Common Focus of the
Climate Change Science and Policy Communities
The well-mixed greenhouse gases are currently the common focus of
climate science and policy analyses and discussions. For example, the
United Nations Framework Convention on Climate Change (UNFCCC), signed
and ratified by the United States in 1992, requires its signatories to
``develop, periodically update, publish and make available * * *
national inventories of anthropogenic emissions by sources and removals
by sinks of all greenhouse gases not controlled by the Montreal
Protocol, using comparable methodologies * * *'' 24 25 To
date, the focus of UNFCCC actions and discussions has been on the six
greenhouse gases that are the same focus of these Findings.
---------------------------------------------------------------------------
\24\ Due to the cumulative purpose of the statutory language,
even if the Administrator were to look at the atmospheric
concentration of each greenhouse gas individually, she would still
consider the impact of the concentration of a single greenhouse gas
in combination with that caused by the other greenhouse gases.
\25\ The range of uncertainty in the current magnitude of black
carbon's climate forcing effect is evidenced by the ranges presented
by the IPCC Fourth Assessment Report (2007) and the more recent
study by Ramanathan, V. and Carmichael, G. (2008) Global and
regional climate changes due to black carbon. Nature Geoscience,
1(4): 221-227.
---------------------------------------------------------------------------
Because of these common properties, it has also become common
practice to compare these gases on a carbon dioxide equivalent basis,
based on each gas's warming effect relative to carbon dioxide (the
designated reference gas) over a specified timeframe. For example, both
the annual Inventory of U.S. Greenhouse Gases and Sinks published by
EPA and the recently finalized EPA Mandatory Greenhouse Gas Reporting
Rule (74 FR 56260), use the carbon dioxide equivalent metric to sum and
compare these gases, and thus accept the common climate-relevant
properties of these gases for their treatment as a group. This is also
common practice internationally as the UNFCCC reporting guidelines for
developed countries, and the Clean Development Mechanism procedures for
developing countries both require the use of global warming potentials
published by the IPCC to convert the six greenhouse gases into their
respective carbon dioxide equivalent units.
4. Defining Air Pollution as the Aggregate Group of Six Greenhouse
Gases Is Consistent With Evaluation of Risks and Impacts Due to Human-
Induced Climate Change
Because the well-mixed greenhouse gases are collectively the
primary driver of current and projected human-induced climate change,
all current and future risks due to human-induced climate change--
whether these risks are associated with increases in temperature,
changes in precipitation, a rise in sea levels, changes in the
frequency and intensity of weather events, or more directly with the
elevated greenhouse gas concentrations themselves--can be associated
with this definition of air pollution.
5. Defining the Air Pollution as the Aggregate Group of Six Greenhouse
Gases Is Consistent With Past EPA Practice
Treating the air pollution as the aggregate of the well-mixed
greenhouse gases is consistent with other provisions of the CAA and
previous EPA practice under the CAA, where separate emissions from
different sources but with common properties may be treated as a class
(e.g., particulate matter (PM)). This approach addresses the total,
cumulative effect that the elevated concentrations of the six well-
mixed greenhouse gases have on climate, and thus on different elements
of health, society and the environment.\24\
EPA treats, for example, PM as a common class of air pollution; PM
is a complex mixture of extremely small particles and liquid droplets.
Particle pollution is made up of a number of components, including
acids (such as nitrates and sulfates), organic chemicals, metals, and
soil or dust particles.
6. Other Climate Forcers Not Being Included in the Definition of Air
Pollution for This Finding
Though the well-mixed greenhouse gases that make up the definition
of air pollution for purposes of making the endangerment decision under
CAA section 202(a) constitute the primary
[[Page 66520]]
driver of human-induced climate change, there are other substances
emitted from human activities that contribute to climate change and
deserve careful attention, but are not being included in the air
pollution definition for this particular action. These substances are
discussed immediately below.
a. Black Carbon
Several commenters request that black carbon be included in the
definition of air pollution because of its warming effect on the
climate. Black carbon is not a greenhouse gas, rather, it is an aerosol
particle that results from the incomplete combustion of carbon
contained in fossil fuels and biomass, and remains in the atmosphere
for only about a week. Unlike any of the greenhouse gases being
addressed by this action, black carbon is a component of particulate
matter (PM), where PM is a criteria air pollutant under section 108 of
the CAA. The extent to which black carbon makes up total PM varies by
emission source, where, for example, diesel vehicle PM emissions
contain a higher fraction of black carbon compared to most other PM
emission sources. Black carbon causes a warming effect primarily by
absorbing incoming and reflected sunlight (whereas greenhouse gases
cause warming by trapping outgoing, infrared heat), and by darkening
bright surfaces such as snow and ice, which reduces reflectivity. This
latter effect, in particular, has been raising concerns about the role
black carbon may be playing in observed warming and ice melt in the
Arctic.
As stated in the April 2009 Proposed Findings, there remain some
significant scientific uncertainties about black carbon's total climate
effect,\25\ as well as concerns about how to treat the short-lived
black carbon emissions alongside the long-lived, well-mixed greenhouse
gases in a common framework (e.g., what are the appropriate metrics to
compare the warming and/or climate effects of the different substances,
given that, unlike greenhouse gases, the magnitude of aerosol effects
can vary immensely with location and season of emissions).
Nevertheless, the Administrator recognizes that black carbon is an
important climate forcing agent and takes very seriously the emerging
science on black carbon's contribution to global climate change in
general and the high rates of observed climate change in the Arctic in
particular. As noted in the Proposed Findings, EPA has various pending
petitions under the CAA calling on the Agency to make an endangerment
finding and regulate black carbon emissions.
b. Other Climate Forcers
There are other climate forcers that play a role in human-induced
climate change that were mentioned in the Proposed Findings, and were
the subject of some public comments. These include the stratospheric
ozone-depleting substances, nitrogen trifluoride (NF3),
water vapor, and tropospheric ozone.
As mentioned above, the ozone-depleting substances (CFCs and HCFCs)
do share the same physical, climate-relevant attributes as the six
well-mixed greenhouse gases; however, emissions of these substances are
playing a diminishing role in human-induced climate change. They are
being controlled and phased out under the Montreal Protocol on
Substances that Deplete the Ozone Layer. Because of this, the major
scientific assessment reports such as those from IPCC focus primarily
on the same six well-mixed greenhouse gases included in the definition
of air pollution in these Findings. It is also worth noting that the
UNFCCC, to which the United States is a signatory, addresses ``all
greenhouse gases not controlled by the Montreal Protocol.'' \26\ One
commenter noted that because the Montreal Protocol controls production
and consumption of ozone-depleting substances, but not existing banks
of the substances, that CFCs should be included in the definition of
air pollution in this finding, which might, in turn, create some future
action under the CAA to address the banks of ozone-depleting substances
as a climate issue. However, the primary criteria for defining the air
pollution in this finding is the focus on the core of the climate
change problem, and concerns over future actions to control depletion
of stratospheric ozone are separate from and not central to the air
pollution causing climate change.
---------------------------------------------------------------------------
\26\ UNFCCC, Art. 4.1(b).
---------------------------------------------------------------------------
Nitrogen trifluoride also shares the same climate-relevant
attributes as the six well-mixed greenhouse gases, and it is also
included in EPA's Mandatory Greenhouse Gas Reporting Rule (FR 74
56260). However, the Administrator is maintaining the reasoning laid
out in the Proposed Findings to not include NF3 in the
definition of air pollution for this finding because the overall
magnitude of its forcing effect on climate is not yet well quantified.
EPA will continue to track the science on NF3.
A number of public comments question the exclusion of water vapor
from the definition of air pollution because it is the most important
greenhouse gas responsible for the natural, background greenhouse
effect. The Administrator's reasoning for excluding water vapor, was
described in the Proposed Findings and is summarized here with
additional information in Volume 10 of the Response to Comments
document. First, climate change is being driven by the buildup in the
atmosphere of greenhouse gases. The direct emissions primarily
responsible for this are the six well-mixed greenhouse gases. Direct
anthropogenic emissions of water vapor, in general, have a negligible
effect and are thus not considered a primary driver of human-induced
climate change. EPA plans to further evaluate the issues of emissions
of water that are implicated in the formation of contrails and also
changes in water vapor due to local irrigation. At this time, however,
the findings of the IPCC state that the total forcing from these
sources is small and that the level of understanding is low.
Water produced as a byproduct of combustion at low altitudes has a
negligible contribution to climate change. The residence time of water
vapor is very short (days) and the water content of the air in the long
term is a function of temperature and partial pressure, with emissions
playing no role. Additionally, the radiative forcing of a given mass of
water at low altitudes is much less than the same mass of carbon
dioxide. Water produced at higher altitudes could potentially have a
larger impact. The IPCC estimated the contribution of changes in
stratospheric water vapor due to methane and other sources, as well as
high altitude contributions from contrails, but concluded that both
contributions were small, with a low level of understanding. The report
also addressed anthropogenic contributions to water vapor arising from
large scale irrigation, but assigned it a very low level of
understanding, and suggested that the cooling from evaporation might
outweigh the warming from its small radiative contribution.
Increases in tropospheric ozone concentrations have exerted a
significant anthropogenic warming effect since pre-industrial times.
However, as explained in the Proposed Findings, tropospheric ozone is
not a long-lived, well-mixed greenhouse gas, and it is not directly
emitted. Rather it forms in the atmosphere from emissions of pre-cursor
gases. There is increasing attention in climate change research and the
policy community about the extent to which further reductions in
tropospheric ozone levels may help
[[Page 66521]]
slow down climate change in the near term. The Administrator views this
issue seriously but maintains that tropospheric ozone is sufficiently
different such that it deserves an evaluation and treatment separate
from this finding.
7. Summary of Key Comments on Definition of Air Pollution
a. It Is Reasonable for the Administrator To Define the Air Pollution
as Global Concentrations of the Well-Mixed Greenhouse Gases
Many commenters argue that EPA does not have the authority to
establish domestic rights and obligations based on environmental
conditions that are largely attributed to foreign nations and entities
that are outside the jurisdiction of EPA under the CAA. They contend
that in this case, the bulk of emissions that would lead to mandatory
emissions controls under the CAA would not and could not be regulated
under the CAA. They state that CAA requirements cannot be enforced
against foreign sources of air pollution, and likewise domestic
obligations under the CAA cannot be caused by foreign emissions that
are outside the United States. The commenters argue that EPA committed
procedural error by not addressing this legal issue of authority in the
proposal.
Commenters cite no statutory text or judicial authority for this
argument, and instead rely entirely on an analogy to the issues
concerning the exercise of extra-territorial jurisdiction. The text of
CAA section 202(a), however, does not support this claim. Nothing in
CAA section 202(a) limits the term air pollution to those air pollution
matters that are caused solely or in large part by domestic emissions.
The only issue under CAA section 202(a) is whether the air pollution is
reasonably anticipated to endanger, and whether emissions from one
domestic source category--new motor vehicles--cause or contribute to
this air pollution. Commenters would read into this an additional cause
or contribute test--whether foreign sources cause or contribute to the
air pollution in such a way that the air pollution is largely
attributable to the foreign emissions, or the bulk of emissions causing
the air pollution are from foreign sources. There is no such provision
in CAA section 202(a). Congress was explicit about the contribution
test it imposed, and the only source that is relevant for purposes of
contribution is new motor vehicles. Commenters suggest an ill-defined
criterion that is not in the statute.
In addition, as discussed in Section II of these Findings, Congress
intentionally meant the agency to judge the air pollution endangerment
criteria based on the ``cumulative impact of all sources of a
pollutant,'' and not an incremental look at just the endangerment from
a subset of sources. Commenters' arguments appear to lead to this
result. Under the commenters' approach, in those cases where the bulk
of emissions which form the air pollution come from foreign sources,
EPA apparently would have no authority to make an endangerment finding.
Logically, EPA would be left with the option of identifying and
evaluating the air pollution attributable to domestic sources alone,
and determining whether that narrowly defined form of air pollution
endangers public health or welfare. This is the kind of unworkable,
incremental approach that was rejected by the court in Ethyl and by
Congress in the 1977 amendments adopting this provision.
The analogy to extra-territorial jurisdiction is also not
appropriate. The endangerment finding itself does not exercise
jurisdiction over any source, domestic or foreign. It is a judgment
that is a precondition for exercising regulatory authority. Under CAA
section 202(a), any exercise of regulatory authority following from
this endangerment finding would be for new motor vehicles either
manufactured in the United States or imported into the United States.
There would be no extra-territorial exercise of jurisdiction. The core
issues for endangerment focus on impacts inside the United States, not
outside the United States. In addition, the contribution finding is
based solely on the contribution from new motor vehicles built in or
imported to the United States. The core judgments that need to be made
under CAA section 202(a) are all focused on actions and impacts inside
the United States. This does not raise any concerns about an extra-
territorial exercise of jurisdiction. The basis for the endangerment
and contribution findings is fully consistent with the principles
underlying the desire to avoid exercises of extra-territorial
jurisdiction. Any limitations on the ability to exercise control over
foreign sources of emissions does not, however, call into question the
authority under CAA section 202 to exercise control over domestic
sources of emissions based on their contribution to an air pollution
problem that is judged to endanger public health or welfare based on
impacts occurring in the United States or otherwise affecting the
United States and its citizens.
In essence, commenters are concerned about the effectiveness of the
domestic control strategies that can be adopted to address a global air
pollution problem that is caused only in part by domestic sources of
emissions. While that is a quite valid and important policy concern, it
does not translate into a legal limitation on EPA's authority to make
an endangerment finding. Neither the text nor the legislative history
of CAA section 202(a) support such an interpretation and Congress
explicitly separated the decision on endangerment from the decision on
what controls are required or appropriate once an affirmative
endangerment finding has been made. The effectiveness of the resulting
regulatory controls is not a relevant factor to determining
endangerment.
EPA also committed no procedural flaw as argued by commenters. The
proposal fully explored the interpretation of endangerment and cause or
contribution under CAA section 202(a), and was very clear that EPA was
considering air pollution to mean the elevated global concentration of
greenhouse gases in the atmosphere, recognizing that these atmospheric
concentrations were the result of world wide emissions, not just or
even largely U.S. emissions. The separation of the effectiveness of the
control strategy from the endangerment criteria, and the need to
consider the cumulative impact of all sources in evaluating
endangerment was clearly discussed. Commenters received fair notice of
EPA's proposal and the basis for it.
Similarly, some commenters argue that EPA's proposal defines air
pollution as global air pollution, but EPA is limited to evaluating
domestic air only; in other words that EPA may only regulate domestic
emissions with localized effects. They argue this limitation derives
from the purpose of the CAA--to enhance the quality of the Nation's air
resources, recognizing that air pollution prevention and control focus
on the sources of the emissions, and are the primary responsibility of
States and local governments. Therefore, commenters continue, that
``air pollution'' has to be air pollution that originates domestically
and is to be addressed only at the domestic source. Sections 115 and
179B of the CAA, as discussed below, reflect this intention as well.
The result, they conclude, is that ``air pollution'' as used in CAA
section 202(a), includes only pollution that originates domestically,
where the effects occur locally. They argue EPA has improperly
circumvented this by a ``local-global-local'' analysis that injects
[[Page 66522]]
global air pollution into the middle of the endangerment test.
The statutory arguments made by the commenters attempt to read an
unrealistic limitation into the general provisions discussed. The
issues are similar in nature to those raised by the commenters arguing
that EPA has no authority to establish domestic rights and obligations
based on environmental conditions that are largely attributable to
emissions from foreign nations and entities that are outside the
jurisdiction of EPA under the CAA. In both cases, the question is
whether EPA has authority to make an endangerment finding when the air
pollution of concern is a relatively homogenous atmospheric
concentration of greenhouse gases. According to the commenters,
although this global pool includes the air over the United States, and
leads to impacts in the United States and on the U.S. population,
Congress prohibited EPA from addressing this air pollution problem
because of its global aspects.
The text of the CAA does not specifically address this, as the term
air pollution is not defined. EPA interprets this term as including the
air pollution problem involved in this case--elevated atmospheric
concentration of greenhouse gases that occur in the air above the
United States as well as across the globe, and where this pool of
global gases leads to impacts in the United States and on the U.S.
population. This is fully consistent with the statutory provisions
discussed by commenters. This approach seeks to protect the Nation's
air resources, as clearly the Nation's air resources are an integral
part of this global pool. The Nation's air resources by definition are
not an isolated atmosphere that only contains molecules emitted within
the United States, or an atmosphere that bears no relationship to the
rest of the globe's atmosphere. There is no such real world body of
air. Protecting the Nation's resources of clean air means to protect
the air in the real world, not an artificial construct of ``air'' that
ignores the many situations where the air over our borders includes
compounds and pollutants emitted outside our borders, and in this case
to ignore the fact that the air over our borders will by definition
have elevated concentrations of greenhouse gases only when the air
around the globe also has such concentrations. The suggested narrow
view of ``air pollution'' does not further the protection of the
Nation's air resources, but instead attempts to limit such protection
by defining these resources in a scientifically artificial way that
does not comport with how the air in the atmosphere is formed or
changes over time, how it relates to and interacts with air around the
globe, and how the result of this can affect the U.S. population.
The approach suggested by commenters fails to provide an actual
definition for EPA to follow--for example, would U.S. or domestic ``air
pollution'' be limited to only those air concentrations composed of
molecules that originated in the United States? Is there a degree of
external gases or compounds that could be allowed? Would it ignore the
interaction and relationship between the air over the U.S. borders and
the air around the rest of the globe? The latter approach appears to be
the one suggested by commenters. Commenters' approach presumably would
call for EPA to only consider the effects that derive solely from the
air over our borders, and to ignore any effects that occur within the
United States that are caused by air around the globe. However the air
over the United States will by definition affect climate change only in
circumstances where the air around the world is also doing so. The
impacts of the air over the United States cannot be assessed separately
from the impacts from the global pool, as they occur together and work
together to affect the climate. Ignoring the real world nature of the
Nation's air resources, in the manner presumably suggested by the
commenters, would involve the kind of unworkable, incremental, and
artificially isolating approach that was rejected by the court in Ethyl
and by Congress in 1977. Congress intended EPA to interpret this
provision by looking at air pollutants and air pollution problems in a
broad manner, not narrowly, to evaluate problems within their broader
context and not to attempt to isolate matters in an artificial way that
fails to account for the real world context that lead to health and
welfare impacts on the public. Commenters' suggested interpretation
fails to implement this intention of Congress.
Commenters in various places refer to the control of the pollution,
and the need for it to be aimed at local sources. That is addressed in
the standard setting portion of CAA section 202(a), as in other similar
provisions. The endangerment provision does not address how the air
pollution problem should be addressed--who should be regulated and how
they should be regulated. The endangerment provision addresses a
different issue--is there an air pollution problem that should be
addressed? In that context, EPA rejects the artificially narrow
interpretation suggested by the commenters, and believes its broader
interpretation in this case is reasonable and consistent with the
intention of Congress.
b. Consideration of Greenhouse Gases as Air Pollution Given Their
Impact Is Through Climate Rather Than Direct Toxic Effects
A number of commenters argue that carbon dioxide and the other
greenhouse gases should not be defined as the air pollution because
these gases do not cause direct human health effects, such as through
inhalation. Responses to such comments are summarized in Section IV.B.1
of these Findings in the discussion of the public health and welfare
nature of the endangerment finding.
c. The Administrator's Reliance on the Global Temperature Data Is a
Reasonable Indicator of Human-Induced Climate Change
We received many comments suggesting global temperatures have
stopped warming. The commenters base this conclusion on temperature
trends over only the last decade. While there have not been strong
trends over the last seven to ten years in global surface temperature
or lower troposphere temperatures measured by satellites, this pause in
warming should not be interpreted as a sign that the Earth is cooling
or that the science supporting continued warming is in error. Year-to-
year variability in natural weather and climate patterns make it
impossible to draw any conclusions about whether the climate system is
warming or cooling from such a limited analysis. Historical data
indicate short-term trends in long-term time series occasionally run
counter to the overall trend. All three major global surface
temperature records show a continuation of long-term warming. Over the
last century, the global average temperature has warmed at the rate of
about 0.13 [deg]F (0.072 [deg]C) per decade in all three records. Over
the last 30 years, the global average surface temperature has warmed by
about 0.30 [deg]F (0.17 [deg]C) per decade. Eight of the 10 warmest
years on record have occurred since 2001 and the 20 warmest years have
all occurred since 1981. Satellite measurements of the troposphere also
indicate warming over the last 30 years at a rate of 0.20 to 0.27
[deg]F (0.11 [deg]C to 0.15 [deg]C) per decade. Please see the relevant
volume of the Response to Comments document for more detailed
responses.
Some commenters indicate the global surface temperature records are
biased by urbanization, poor siting of instruments, observation
methods, and
[[Page 66523]]
other factors. Our review of the literature suggests that these biases
have in many cases been corrected for, are largely random where they
remain, and therefore cancel out over large regions. Furthermore, we
note that though the three global surface temperature records use
differing techniques to analyze much of the same data, they produce
almost the same results, increasing our confidence in their legitimacy.
The assessment literature has concluded that warming of the climate
system is unequivocal. The warming trend that is evident in all of the
temperature records is confirmed by other independent observations,
such as the melting of Arctic sea ice, the retreat of mountain glaciers
on every continent, reductions in the extent of snow cover, earlier
blooming of plants in the spring, and increased melting of the
Greenland and Antarctic ice sheets. Please see the relevant volume of
the Response to Comments document for more detailed responses.
A number of commenters argue that the warmth of the late 20th
century is not unusual relative to the past 1,000 years. They maintain
temperatures were comparably warm during the Medieval Warm Period (MWP)
centered around 1000 A.D. We agree there was a Medieval Warm Period in
many regions but find the evidence is insufficient to assess whether it
was globally coherent. Our review of the available evidence suggests
that Northern Hemisphere temperatures in the MWP were probably between
0.1 [deg]C and 0.2 [deg]C below the 1961-1990 mean and significantly
below the level shown by instrumental data after 1980. However, we note
significant uncertainty in the temperature record prior to 1600 A.D.
Please see the relevant volume of the Response to Comments document for
more detailed responses.
d. Ability To Attribute Observed Climate Change to Anthropogenic, Well-
Mixed Greenhouse Gases
Many commenters question the link between observed temperatures and
anthropogenic greenhouse gas emissions. They suggest internal
variability of the climate system and natural forcings explain observed
temperature trends and that anthropogenic greenhouse gases play, at
most, a minor role. However, the attribution of most of the recent
warming to anthropogenic activities is based on multiple lines of
evidence. The first line of evidence arises from our basic physical
understanding of the effects of changing concentrations of greenhouse
gases, natural factors, and other human impacts on the climate system.
Greenhouse gas concentrations have indisputably increased and their
radiative properties are well established. The second line of evidence
arises from indirect, historical estimates of past climate changes that
suggest that the changes in global surface temperature over the last
several decades are unusual. The third line of evidence arises from the
use of computer-based climate models to simulate the likely patterns of
response of the climate system to different forcing mechanisms (both
natural and anthropogenic). These models are unable to replicate the
observed warming unless anthropogenic emissions of greenhouse gases are
included in the simulations. Natural forcing alone cannot explain the
observed warming. In fact, the assessment literature \27\ indicates the
sum of solar and volcanic forcing in the past half century would likely
have produced cooling, not warming. Please see the relevant volume of
the Response to Comments for more detailed responses.
---------------------------------------------------------------------------
\27\ Solomon, S., D. Qin, M. Manning, R.B. Alley, T. Berntsen,
N.L. Bindoff, Z. Chen, A. Chidthaisong, J.M. Gregory, G.C. Hegerl,
M. Heimann, B. Hewitson, B.J. Hoskins, F. Joos, J. Jouzel, V.
Kattsov, U. Lohmann, T. Matsuno, M. Molina, N. Nicholls, J.
Overpeck, G. Raga, V. Ramaswamy, J. Ren, M. Rusticucci, R.
Somerville, T.F. Stocker, P. Whetton, R.A. Wood and D. Wratt (2007)
Technical Summary. In: Climate Change 2007: The Physical Science
Basis. Contribution of Working Group I to the Fourth Assessment
Report of the Intergovernmental Panel on Climate Change [Solomon,
S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor,
and H.L. Miller (eds.)]. Cambridge University Press, Cambridge,
United Kingdom and New York, NY, USA. Karl, T. et al. (2009).
---------------------------------------------------------------------------
B. The Air Pollution Is Reasonably Anticipated To Endanger Both Public
Health and Welfare
The Administrator finds that the elevated atmospheric
concentrations of the well-mixed greenhouse gases may reasonably be
anticipated to endanger the public health and welfare of current and
future generations. This section describes the major pieces of
scientific evidence supporting the Administrator's endangerment
finding, discusses both the public health and welfare nature of the
endangerment finding, and addresses a number of key issues the
Administrator considered when evaluating the state of the science as
well as key public comments on the Proposed Findings. Additional detail
can be found in the TSD and the Response to Comments document.
As described in Section II of these Findings, the endangerment test
under CAA section 202(a) does not require the Administrator to identify
a bright line, quantitative threshold above which a positive
endangerment finding can be made. The statutory language explicitly
calls upon the Administrator to use her judgment. This section
describes the general approach used by the Administrator in reaching
the judgment that a positive endangerment finding should be made, as
well as the specific rationale for finding that the greenhouse gas air
pollution may reasonably be anticipated to endanger both public health
and welfare.
First, the Administrator finds the scientific evidence linking
human emissions and resulting elevated atmospheric concentrations of
the six well-mixed greenhouse gases to observed global and regional
temperature increases and other climate changes to be sufficiently
robust and compelling. This evidence is briefly explained in more
detail in Section V of these Findings. The Administrator recognizes
that the climate change associated with elevated atmospheric
concentrations of carbon dioxide and the other well-mixed greenhouse
gases have the potential to affect essentially every aspect of human
health, society and the natural environment. The Administrator is
therefore not limiting her consideration of potential risks and impacts
associated with human emissions of greenhouse gases to any one
particular element of human health, sector of the economy, region of
the country, or to any one particular aspect of the natural
environment. Rather, the Administrator is basing her finding on the
total weight of scientific evidence, and what the science has to say
regarding the nature and potential magnitude of the risks and impacts
across all climate-sensitive elements of public health and welfare, now
and projected out into the foreseeable future.
The Administrator has considered the state of the science on how
human emissions and the resulting elevated atmospheric concentrations
of well-mixed greenhouse gases may affect each of the major risk
categories, i.e., those that are described in the TSD, which include
human health, air quality, food production and agriculture, forestry,
water resources, sea level rise and coastal areas, the energy sector,
infrastructure and settlements, and ecosystems and wildlife. The
Administrator understands that the nature and potential severity of
impacts can vary across these different elements of public health and
welfare, and that they can vary by region, as well as over time.
The Administrator is therefore aware that, because human-induced
climate change has the potential to be far-reaching and multi-
dimensional, not all
[[Page 66524]]
risks and potential impacts can be characterized with a uniform level
of quantification or understanding, nor can they be characterized with
uniform metrics. Given this variety in not only the nature and
potential magnitude of risks and impacts, but also in our ability to
characterize, quantify and project into the future such impacts, the
Administrator must use her judgment to weigh the threat in each of the
risk categories, weigh the potential benefits where relevant, and
ultimately judge whether these risks and benefits, when viewed in
total, are judged to be endangerment to public health and/or welfare.
This has a number of implications for the Administrator's approach
in assessing the nature and magnitude of risk and impacts across each
of the risk categories. First, the Administrator has not established a
specific threshold metric for each category of risk and impacts. Also,
the Administrator is not necessarily placing the greatest weight on
those risks and impacts which have been the subject of the most study
or quantification.
Part of the variation in risks and impacts is the fact that
climbing atmospheric concentrations of greenhouse gases and associated
temperature increases can bring about some potential benefits to public
health and welfare in addition to adverse risks. The current
understanding of any potential benefits associated with human-induced
climate change is described in the TSD and is taken into consideration
here. The potential for both adverse and beneficial effects are
considered, as well as the relative magnitude of such effects, to the
extent that the relative magnitudes can be quantified or characterized.
Furthermore, given the multiple ways in which the buildup of
atmospheric greenhouse gases can cause effects (e.g., via elevated
carbon dioxide concentrations, via temperature increases, via
precipitation increases, via sea level rise, and via changes in extreme
events), these multiple pathways are considered. For example, elevated
carbon dioxide concentrations may be beneficial to crop yields, but
changes in temperature and precipitation may be adverse and must also
be considered. Likewise, modest temperature increases may have some
public health benefits as well as harms, and other pathways such as
changes in air quality and extreme events must also be considered.
The Administrator has balanced and weighed the varying risks and
effects for each sector. She has judged whether there is a pattern
across the sector that supports or does not support an endangerment
finding, and if so whether the support is of more or less weight. In
cases where there is both a potential for benefits and risks of harm,
the Administrator has balanced these factors by determining whether
there appears to be any directional trend in the overall evidence that
would support placing more weight on one than the other, taking into
consideration all that is known about the likelihood of the various
risks and effects and their seriousness. In all of these cases, the
judgment is largely qualitative in nature, and is not reducible to
precise metrics or quantification.
Regarding the timeframe for the endangerment test, it is the
Administrator's view that both current and future conditions must be
considered. The Administrator is thus taking the view that the
endangerment period of analysis extend from the current time to the
next several decades, and in some cases to the end of this century.
This consideration is also consistent with the timeframes used in the
underlying scientific assessments. The future timeframe under
consideration is consistent with the atmospheric lifetime and climate
effects of the six well-mixed greenhouse gases, and also with our
ability to make reasonable and plausible projections of future
conditions.
The Administrator acknowledges that some aspects of climate change
science and the projected impacts are more certain than others. Our
state of knowledge is strongest for recently observed, large-scale
changes. Uncertainty tends to increase in characterizing changes at
smaller (regional) scales relative to large (global) scales.
Uncertainty also increases as the temporal scales move away from
present, either backward, but more importantly forward in time.
Nonetheless, the current state of knowledge of observed and past
climate changes and their causes enables projections of plausible
future changes under different scenarios of anthropogenic forcing for a
range of spatial and temporal scales.
In some cases, where the level of sensitivity to climate of a
particular sector has been extensively studied, future impacts can be
quantified whereas in other instances only a qualitative description of
a directional change, if that, may be possible. The inherent
uncertainty in the direction, magnitude, and/or rate of certain future
climate change impacts opens up the possibility that some changes could
be more or less severe than expected, and the possibility of
unanticipated outcomes. In some cases, low probability, high impact
outcomes (i.e., known unknowns) are possibilities but cannot be
explicitly assessed.
1. The Air Pollution Is Reasonably Anticipated To Endanger Public
Health
The Administrator finds that the well-mixed greenhouse gas air
pollution is reasonably anticipated to endanger public health, for both
current and future generations. The Administrator finds that the public
health of current generations is endangered and that the threat to
public health for both current and future generations will likely mount
over time as greenhouse gases continue to accumulate in the atmosphere
and result in ever greater rates of climate change.
After review of public comments, the Administrator continues to
believe that climate change can increase the risk of morbidity and
mortality and that these public health impacts can and should be
considered when determining endangerment to public health under CAA
section 202(a). As described in Section IV.B.1 of these Findings, the
Administrator is not limited to only considering whether there are any
direct health effects such as respiratory or toxic effects associated
with exposure to greenhouse gases.
In making this public health finding, the Administrator considered
direct temperature effects, air quality effects, the potential for
changes in vector-borne diseases, and the potential for changes in the
severity and frequency of extreme weather events. In addition, the
Administrator considered whether and how susceptible populations may be
particularly at risk. The current state of science on these effects
from the major assessment reports is described in greater detail in the
TSD, and our responses to public comments are provided in the Response
to Comments Documents.
a. Direct Temperature Effects
It has been estimated that unusually hot days and heat waves are
becoming more frequent, and that unusually cold days are becoming less
frequent, as noted above. Heat is already the leading cause of weather-
related deaths in the United States. In the future, severe heat waves
are projected to intensify in magnitude and duration over the portions
of the United States where these events already occur. Heat waves are
associated with marked short-term increases in mortality. Hot
temperatures have also been associated with increased morbidity. The
projected warming is therefore projected to increase heat related
mortality and
[[Page 66525]]
morbidity, especially among the elderly, young and frail. The
populations most sensitive to hot temperatures are older adults, the
chronically sick, the very young, city-dwellers, those taking
medications that disrupt thermoregulation, the mentally ill, those
lacking access to air conditioning, those working or playing outdoors,
and socially isolated persons. As warming increases over time, these
adverse effects would be expected to increase as the serious heat
events become more serious.
Increases in temperature are also expected to lead to some
reduction in the risk of death related to extreme cold. Cold waves
continue to pose health risks in northern latitudes in temperature
regions where very low temperatures can be reached in a few hours and
extend over long periods. Globally, the IPCC projects reduced human
mortality from cold exposure through 2100. It is not clear whether
reduced mortality in the United States from cold would be greater or
less than increased heat-related mortality in the United States due to
climate change. However, there is a risk that projections of cold-
related deaths, and the potential for decreasing their numbers due to
warmer winters, can be overestimated unless they take into account the
effects of season and influenza, which is not strongly associated with
monthly winter temperature. In addition, the latest USGCRP report
refers to a study that analyzed daily mortality and weather data in 50
U.S. cities from 1989 to 2000 and found that, on average, cold snaps in
the United States increased death rates by 1.6 percent, while heat
waves triggered a 5.7 percent increase in death rates. The study
concludes that increases in heat-related mortality due to global
warming in the United States are unlikely to be compensated for by
decreases in cold-related mortality.
b. Air Quality Effects
Increases in regional ozone pollution relative to ozone levels
without climate change are expected due to higher temperatures and
weaker circulation in the United States relative to air quality levels
without climate change. Climate change is expected to increase regional
ozone pollution, with associated risks in respiratory illnesses and
premature death. In addition to human health effects, tropospheric
ozone has significant adverse effects on crop yields, pasture and
forest growth, and species composition. The directional effect of
climate change on ambient particulate matter levels remains less
certain.
Climate change can affect ozone by modifying emissions of
precursors, atmospheric chemistry, and transport and removal. There is
now consistent evidence from models and observations that 21st century
climate change will worsen summertime surface ozone in polluted regions
of North America compared to a future with no climate change.
Modeling studies discussed in EPA's Interim Assessment \28\ show
that simulated climate change causes increases in summertime ozone
concentrations over substantial regions of the country, though this was
not uniform, and some areas showed little change or decreases, though
the decreases tend to be less pronounced than the increases. For those
regions that showed climate-induced increases, the increase in maximum
daily 8-hour average ozone concentration, a key metric for regulating
U.S. air quality, was in the range of 2 to 8 ppb, averaged over the
summer season. The increases were substantially greater than this
during the peak pollution episodes that tend to occur over a number of
days each summer. The overall effect of climate change was projected to
increase ozone levels, compared to what would occur without this
climate change, over broad areas of the country, especially on the
highest ozone days and in the largest metropolitan areas with the worst
ozone problems. Ozone decreases are projected to be less pronounced,
and generally to be limited to some regions of the country with smaller
population.
---------------------------------------------------------------------------
\28\ U.S. EPA (2009) Assessment of the Impacts of Global Change
on Regional U.S. Air Quality: A Synthesis of Climate Change Impacts
on Ground-Level Ozone. An Interim Report of the U.S. EPA Global
Change Research Program. U.S. Environmental Protection Agency,
Washington, DC, EPA/600/R-07/094.
---------------------------------------------------------------------------
c. Effects on Extreme Weather Events
In addition to the direct effects of temperature on heat- and cold-
related mortality, the Administrator considers the potential for
increased deaths, injuries, infectious diseases, and stress-related
disorders and other adverse effects associated with social disruption
and migration from more frequent extreme weather. The Administrator
notes that the vulnerability to weather disasters depends on the
attributes of the people at risk (including where they live, age,
income, education, and disability) and on broader social and
environmental factors (level of disaster preparedness, health sector
responses, and environmental degradation). The IPCC finds the following
with regard to extreme events and human health:
Increases in the frequency of heavy precipitation events are
associated with increased risk of deaths and injuries as well as
infectious, respiratory, and skin diseases. Floods are low-probability,
high-impact events that can overwhelm physical infrastructure, human
resilience, and social organization. Flood health impacts include
deaths, injuries, infectious diseases, intoxications, and mental health
problems.
Increases in tropical cyclone intensity are linked to increases in
the risk of deaths, injuries, waterborne and food borne diseases, as
well as post-traumatic stress disorders. Drowning by storm surge,
heightened by rising sea levels and more intense storms (as projected
by IPCC), is the major killer in coastal storms where there are large
numbers of deaths. Flooding can cause health impacts including direct
injuries as well as increased incidence of waterborne diseases due to
pathogens such as Cryptosporidium and Giardia.
d. Effects on Climate-Sensitive Diseases and Aeroallergens
According to the assessment literature, there will likely be an
increase in the spread of several food and water-borne pathogens among
susceptible populations depending on the pathogens' survival,
persistence, habitat range and transmission under changing climate and
environmental conditions. Food borne diseases show some relationship
with temperature, and the range of some zoonotic disease carriers such
as the Lyme disease carrying tick may increase with temperature.
Climate change, including changes in carbon dioxide concentrations,
could impact the production, distribution, dispersion and allergenicity
of aeroallergens and the growth and distribution of weeds, grasses, and
trees that produce them. These changes in aeroallergens and subsequent
human exposures could affect the prevalence and severity of allergy
symptoms. However, the scientific literature does not provide
definitive data or conclusions on how climate change might impact
aeroallergens and subsequently the prevalence of allergenic illnesses
in the United States.
It has generally been observed that the presence of elevated carbon
dioxide concentrations and temperatures stimulate plants to increase
photosynthesis, biomass, water use efficiency, and reproductive effort.
The IPCC concluded that pollens are likely to increase with elevated
temperature and carbon dioxide.
[[Page 66526]]
e. Summary of the Administrator's Finding of Endangerment to Public
Health
The Administrator has considered how elevated concentrations of the
well-mixed greenhouse gases and associated climate change affect public
health by evaluating the risks associated with changes in air quality,
increases in temperatures, changes in extreme weather events, increases
in food and water borne pathogens, and changes in aeroallergens. The
evidence concerning adverse air quality impacts provides strong and
clear support for an endangerment finding. Increases in ambient ozone
are expected to occur over broad areas of the country, and they are
expected to increase serious adverse health effects in large population
areas that are and may continue to be in nonattainment. The evaluation
of the potential risks associated with increases in ozone in attainment
areas also supports such a finding.
The impact on mortality and morbidity associated with increases in
average temperatures which increase the likelihood of heat waves also
provides support for a public health endangerment finding. There are
uncertainties over the net health impacts of a temperature increase due
to decreases in cold-related mortality, but there is some recent
evidence that suggests that the net impact on mortality is more likely
to be adverse, in a context where heat is already the leading cause of
weather-related deaths in the United States.
The evidence concerning how human-induced climate change may alter
extreme weather events also clearly supports a finding of endangerment,
given the serious adverse impacts that can result from such events and
the increase in risk, even if small, of the occurrence and intensity of
events such as hurricanes and floods. Additionally, public health is
expected to be adversely affected by an increase in the severity of
coastal storm events due to rising sea levels.
There is some evidence that elevated carbon dioxide concentrations
and climate changes can lead to changes in aeroallergens that could
increase the potential for allergenic illnesses. The evidence on
pathogen borne disease vectors provides directional support for an
endangerment finding. The Administrator acknowledges the many
uncertainties in these areas. Although these adverse effects, provide
some support for an endangerment finding, the Administrator is not
placing primary weight on these factors.
Finally, the Administrator places weight on the fact that certain
groups, including children, the elderly, and the poor, are most
vulnerable to these climate-related health effects.
f. Key Comments on the Finding of Endangerment to Public Health
EPA received many comments on public health issues and the proposed
finding of endangerment to public health.
i. EPA's Consideration of the Climate Impacts as Public Health Issues
Is Reasonable
Several commenters argue that EPA may only consider the health
effects from direct exposure to pollutants in determining whether a
pollutant endangers public health. The commenters state that EPA's
proposal acknowledges that there is no evidence that greenhouse gases
directly cause health effects, citing 74 FR 18901. To support their
claim that EPA can only consider health effects that result from direct
exposure to a pollutant, commenters cite several sources, discussed
below.
Clean Air Act and Legislative History. Several commenters argue
that the text of the CAA and the legislative history of the 1977
amendments demonstrate that Congress intended public health effects to
relate to risks from direct exposure to a pollutant. They also argue
that by considering health effects that result from welfare effects,
EPA was essentially combining the two categories into one, contrary to
the statute and Congressional intent.
Commenters state that the CAA, including CAA section 202(a)(1),
requires EPA to consider endangerment of public health separately from
endangerment of public welfare. Commenters note that while the CAA does
not provide a definition of public health, CAA section 302(h) addresses
the meaning of ``welfare,'' which includes weather and climate. Thus,
they argue, Congress has instructed that effects on weather and climate
are to be considered as potentially endangering welfare--not human
health. They continue that Congress surely knew that weather and
climatic events such as flooding and heat waves could affect human
health, but Congress nonetheless classified air pollutants' effects on
weather and climate as effects on welfare.
Commenters also argue that the legislative history confirms that
Congress intended for the definition of ``public health'' to only
include the consequences of direct human exposure to ambient air
pollutants. They note an early version of section 109(b) would have
required only a single NAAQS standard to protect ``public health,''
with the protection of ``welfare'' being a co-benefit of the single
standard. Commenters note that the proponents of this early bill
explained, ``[i]n many cases, a level of protection of health would
take care of the welfare situation'' Sen. Hearing, Subcommittee on Air
and Water Pollution, Comm. On Public Works (Mar. 17, 1970) (statement
of Dr. Middleton, Comm'r, Nat'l Air Pollution Control Admin., HEW),
1970 Leg. Hist. 1194. Commenters state that the Senate bill that
ultimately passed rejected this combined standard, requiring separate
national ambient air quality standards and national ambient air quality
goals. Commenters contend that Congress intended that the national
ambient air quality goals be set ``to protect the public health and
welfare from any known or anticipated effects associated with'' air
pollution, including the list of ``welfare'' effects currently found in
CAA section 302(h), such as effects on water, vegetation, animals,
wildlife, weather and climate. Commenters note the Senate Committee
Report stated that the national ambient air quality standards were
created to protect public health, while the national ambient air
quality goals were intended to address broader issues because ``the
Committee also recognizes that man's natural and man-made environment
must be preserved and protected. Therefore, the bill provides for the
setting of national ambient air quality goals at levels necessary to
protect public health and welfare from any known or anticipated adverse
effects of air pollution--including effects on soils, water,
vegetation, man-made materials, animals, wildlife, visibility, climate,
and economic values.'' Commenters argue this statement is clearly the
source of the current definition of welfare effects in CAA section
302(h), which also includes ``personal comfort and well being.'' They
argue the Senate bill contemplated the NAAQS would include only direct
health effects, while the goals would encompass effects on both the
public health and welfare. Commenters continue that considering both
public health effects and welfare effects under a combined standard, as
the Administrator attempts to do in the proposed endangerment finding,
would resurrect the combined approach to NAAQS that the Senate
emphatically rejected.
The commenters also cite language from the House Report in support
of their view that Congress only intended that EPA consider direct
health effects
[[Page 66527]]
when assessing endangerment to public health: ``By the words `cause or
contribute to air pollution,' the committee intends to require the
Administrator to consider all sources of the contaminant which
contributes to air pollution and to consider all sources of exposure to
the contaminant--food, water, air, etc.--in determining health risks''
7 H.R. Rep. No. 95-294, at 49-50 (1977). Commenters also cite language
in the Senate Report: ``Knowledge of the relationship between the
exposure to many air pollution agents and acute and chronic health
effects is sufficient to develop air quality criteria related to such
effects'' S. Rep. No. 91-1196, at 7 (1970).
The specific issue here is whether an effect on human health that
results from a change in climate should be considered when EPA
determines whether the air pollution of well-mixed greenhouse gases is
reasonably anticipated to endanger public health. In this case, the air
pollution has an effect on climate. For example the air pollution
raises surface, air, and water temperatures. Among the many effects
that flow from this is the expectation that there will be an increase
in the risk of mortality and morbidity associated with increased
intensity of heat waves. In addition, there is an expectation that
there will be an increase in levels of ambient ozone, leading to
increased risk of morbidity and mortality from exposure to ozone. All
of these are effects on human health, and all of them are associated
with the effect on climate from elevated atmospheric concentrations of
greenhouse gases. None of these human health effects are associated
with direct exposure to greenhouse gases.
In the past, EPA has not had to resolve the issue presented here,
as it has been clear whether the effects relate to public health or
relate to public welfare, with no confusion over what category was at
issue. In those cases EPA has routinely looked at what effect the air
pollution has on people. If the effect on people is to their health, we
have considered it an issue of public health. If the effect on people
is to their interest in matters other than health, we have considered
it public welfare.
For example, there are serious health risks associated with
inhalation of ozone, and they have logically been considered as public
health issues. Ambient levels of ozone have also raised the question of
indirect health benefits through screening of harmful UVB rays. EPA has
also considered this indirect health effect of ozone to be a public
health issue.\29\ Ozone pollution also affects people by impacting
their interests in various vegetation through foliar damage to trees,
reduced crop yield, adverse impacts on horticultural plants, and the
like. EPA has consistently considered these issues when evaluating the
public welfare based NAAQS standards under CAA section 109.
---------------------------------------------------------------------------
\29\ As discussed later, in the past EPA took the position that
this kind of potential indirect beneficial impact on public health
should not be considered when setting the primary health based NAAQS
for ozone. This was not based on the view that it was not a
potential public health impact, or that it was a public welfare
impact instead of a public health impact. Instead EPA was
interpreting the NAAQS standard setting provisions of section 109,
and argued that they were intended to address only certain public
health impacts, those that were adverse, and were not intended to
address indirect, beneficial public health impacts. This
interpretation of section 109 was rejected in ATA v. EPA, 175 F.3d
1027 (1999) reh'g granted in part and denied in part, 195 F.3d 4 (DC
Cir. 1999). The court made it clear that the potential indirect
beneficial impact of ambient ozone on public health from screening
UVB rays needed to be considered when setting the NAAQS to protect
public health.
---------------------------------------------------------------------------
In all of these situations the use of the term ``public'' has
focused EPA on how people are affected by the air pollution. If the
effect on people is to their health then we have considered it a public
health issue. If the effect on people is to their interest in matters
other than health, then we have treated it as a public welfare issue.
The situation presented here is somewhat unique. The focus again is
on the effect the air pollution has on people. Here the effect on
people is to their health. However this effect flows from the change in
climate and effects on climate are included in the definition of
effects on welfare. That raises the issue of how to categorize the
health effects--should we consider them when evaluating endangerment to
public health? When we evaluate endangerment to public welfare? Or
both?
The text of the CAA does not resolve this question. While Congress
defined ``effects on welfare,'' it did not define either ``public
health'' or ``public welfare''. In addition, the definition of
``effects on welfare'' does not clearly address how to categorize
health effects that flow from effects on soils, water, crops,
vegetation, weather, climate, or any of the other factors listed in CAA
section 302(h). It is clear that effects on climate are an effect on
welfare, but the definition does not address whether health impacts
that are caused by these changes in climate are also effects on
welfare. The health effects at issue are not themselves effects on
soils, water, crops, vegetation, weather, or climate. They are instead
effects on health. They derive from the effects on climate, but they
are not themselves effects on climate or on anything else listed in CAA
section 302(h). So the definition of effects on welfare does not
address whether an effect on health, which is not itself listed in CAA
section 302(h), is also an effect on welfare if it results from an
effect on welfare. The text of the CAA also does not address the issue
of direct and indirect health effects. Contrary to commenters'
assertions, the legislative history does not address or resolve this
issue.
In this context, EPA is interpreting the endangerment provision in
CAA section 202(a) as meaning that the effects on peoples' health from
changes to climate can and should be included in EPA's evaluation of
whether the air pollution at issue endangers public health. EPA is not
deciding whether these health effects also could or should be
considered in evaluating endangerment to public welfare.
The stating of the issue makes the answer seem straightforward. If
air pollution causes sickness or death, then these health effects
should be considered when evaluating whether the air pollution
endangers public health. The term public health is undefined, and by
itself this is an eminently reasonable way to interpret it. This
focuses on the actual effect on people, as compared to ignoring that
and focusing on the pathway from the air pollution to the effect. The
question then becomes whether there is a valid basis in the CAA to take
the different approach suggested by commenters, an approach contrary to
the common sense meaning of public health.
Notably, the term ``public welfare'' is undefined. While it clearly
means something other than public health, there is no obvious
indication whether Congress intended there to be a clear boundary
between the two terms or whether there might be some overlap where some
impacts could be considered both a public health and a public welfare
impact. Neither the text nor the legislative history resolves this
issue. Under either approach, EPA believes the proper interpretation is
that these effects on health should be considered when evaluating
endangerment to public health.
If we assume Congress intended that effects on public welfare could
not include effects on public health and vice versa, then the effects
at issue here should most reasonably be considered in the public health
category. Indisputably they are health effects, and the plain meaning
of the term public health would call for their inclusion in that term.
The term public welfare is
[[Page 66528]]
undefined. If Congress intended that public welfare not include matters
included in the public health category, then a reasonable
interpretation of this undefined term would include those effects on
welfare that impact people in ways other than impacting their health.
The definition of ``effects on welfare'' does not clearly address
how to categorize health effects that flow from effects on water, soil,
land, climate, or weather. As noted above, the definition does not
address whether health impacts that are caused by these changes in
climate are also ``effects on welfare.'' Certainly effects on health
are not included in the list in CAA section 302(h). The lack of clarity
in the definition of effects on welfare, combined with the lack of
definition of public welfare, do not warrant interpreting the term
public health differently from its straightforward and common sense
meaning.
The inclusion of the phrase ``effects on * * * personal comfort and
well-being'' as an effect on welfare supports this view. The term would
logically mean something other than the different term public health.
The term ``well-being'' is not defined, and generally has a broader and
different connotation of positive physical, emotional, and mental
status. The most straightforward meaning of this term, in a context
where Congress used the different term public health in a wide variety
of other provisions, would be to include effects on people that do not
rise to the level of health effects, but otherwise impact their
physical, emotional, and mental status. This gives full meaning to both
terms.
The term well-being is a general term, and in isolation arguably
could include health effects. However there is no textual basis to say
it would include some health effects but not others, as argued by
commenters. If sickness impacts your well-being, then it impacts your
well-being whether it results directly or indirectly from the pollution
in the air. Nothing in CAA section 302(h) limits the term well-being to
indirect impacts on people, or to health effects that occur because of
other welfare effects, such as climate change. It is listed as its own
effect on welfare. Instead of interpreting well-being as including all
health effects, or some health effects, the much more logical way to
interpret this provision in the context of all of the other provisions
of the CAA is to interpret it as meaning effects on people other than
health effects.
Thus, if Congress intended to draw a strict line between the two
categories of public health and public welfare, for purposes of
determining endangerment under CAA section 202(a), then EPA believes
that its interpretation is a reasonable and straightforward way to
categorize the health effects at issue here. This gives weight to the
common sense meaning of the term public health, where the terms public
health and public welfare are undefined and the definition of effects
on welfare is at best ambiguous on this issue.
In the alternative, if Congress did not intend any such bright line
between these two categories and there could be an overlap, then it is
also reasonable for EPA to include these health effects in its
consideration of whether the air pollution endangers public health.
Neither approach condenses or conflates the two different terms. Under
either approach EPA's interpretation, as demonstrated in this
rulemaking, would still consider numerous and varied effects from
climate change as indisputable impacts on public welfare and not
impacts on public health. In addition, this interpretation will not
change the fact that in almost all cases impacts on public health would
not also be considered impacts on public welfare.
Prior EPA actions. Several commenters argue that EPA's decision to
include health impacts that occur because of climate change is
inconsistent with its past approach, which has been to treat indirect
health effects as welfare effects. Commenters contend that in the
latest Criteria Document for ozone EPA listed tropospheric ozone's
effects on UVB-induced human diseases, as well as its effects on
climate change, as welfare effects, even though the agency acknowledged
significant health effects such as sunburn and skin cancer. Commenters
also argue that EPA listed ``risks to human health'' from toxins
released by algal blooms due to excess nitrogen as ``ecological and
other welfare effects'' in the recent Criteria Document for oxides of
nitrogen and sulfur. Finally, commenters argue that EPA's proposed
action was contrary to the Agency decision to list new municipal solid
waste landfills as a source category under CAA section 111. Commenters
state that EPA listed climate change as a welfare effect in that
action, (citing 56 FR 24469).
The Agency's recent approach regarding UVB-induced health effects
is consistent with the endangerment findings, and demonstrates that the
Agency considers indirect effects on human health as public health
issues rather than public welfare issues. While the ozone Criteria
Document may have placed the discussion of UV-B related health effects
among chapters on welfare effects, in evaluating the evidence presented
in the Criteria Document for purposes of preparing the policy
assessment document, EPA staff clearly viewed UVB-induced effects as
human health effects that were relevant in determining the public
health based primary NAAQS for ozone, rather than welfare effects,
regardless of which chapter in the Criteria Document described those
effects. The evaluation of the UVB-related evidence is discussed with
other human health effects evidence. The policy assessment document
noted that Chapter 10 of the Criteria Document, ``provides a thorough
analysis of the current understanding of the relationship between
reducing tropospheric [ozone] concentrations and the potential impact
these reductions might have on UV-B surface fluxes and indirectly
contributing to increased UV-B related health effects.'' See, Review of
the National Ambient Air Quality Standards for Ozone: Policy Assessment
of Scientific and Technical Information, p 3-36 (January 2007)
(emphasis added).
EPA repeated this view in the 2007 proposed ozone NAAQS rule. In
presenting its evaluation of the human health evidence for purposes of
setting the public health based primary NAAQS, EPA stated: ``This
section also summarizes the uncertainty about the potential indirect
effects on public health associated with changes due to increases in
UV-B radiation exposure, such as UV-B radiation-related skin cancers,
that may be associated with reductions in ambient levels of ground-
level [ozone], as discussed in chapter 10 of the Criteria Document and
chapter 3 of the Staff Paper.'' 72 FR 37818, 37827. See also, 72 FR
37837 (``* * * the Criteria Document also assesses the potential
indirect effects related to the presence of [ozone] in the ambient air
by considering the role of ground-level [ozone] in mediating human
health effects that may be directly attributable to exposure to solar
ultraviolet radiation (UV-B).'')
Thus, EPA's approach to UV-B related health effects clearly shows
the Agency has treated indirect health effects not as welfare effects,
as commenters suggest, but as human health effects that need to be
evaluated when setting the public health based primary NAAQS. In this
ozone NAAQS rulemaking, EPA did not draw a line between direct and
indirect health effects for purposes of evaluating UV-B related health
effects and the public health based primary NAAQS.
[[Page 66529]]
Similarly, the NOX/SOX criteria document does
not establish a precedent that indirect human health effects are
welfare effects. Toxic algal blooms themselves are a welfare effect, so
it is not surprising a discussion of algal blooms appears in sections
dealing with welfare effects. The more relevant question is how EPA
evaluated information regarding human health risks resulting from algal
blooms. In the case of the Criteria Document, the role of nitrogen in
causing algal blooms was unclear. As a result, the Agency did not have
occasion to evaluate any resulting human health effects and the
Criteria Document does not support the view that EPA treats indirect
health effects as anything other than a public health issue.
Finally, EPA disagrees that its action here is at odds with the
listing of municipal solid waste landfills under CAA section 111. In
the landfills New Source Performance Standard (NSPS) EPA did not
consider health effects resulting from climate change much less draw
any conclusions about health effects from climate change being health
or welfare effects. If anything, the landfills NSPS is consistent with
EPA's approach. In the proposed rule, EPA stated: ``The EPA has
documented many cases of acute injury and death caused by explosions
and fires related to municipal landfill gas emissions. In addition to
these health effects, the associated property damage is a welfare
effect'' (56 FR 24474). EPA considered injury and death from fires
resulting from landfill gasses to be health effects. Yet the injury did
not result from direct exposure to the pollutant (landfill gas).
Instead, the injury resulted from the combustion of the pollutant--the
injury is essentially an indirect effect of the pollutant. Yet, as with
this action, EPA considered the injury as a human health effect.
Case law. Several commenters argue that EPA's proposed endangerment
finding was inconsistent with NRDC v. EPA, 902 F.2d 962 (DC Cir 1990).
Commenters argue that in rejecting the argument that EPA must consider
the health effects of increased unemployment that could result from a
more stringent primary NAAQS standard, the DC Circuit explained that,
``[i]t is only the health effects relating to pollutants in the air
that EPA may consider.'' Id. at 973. Several commenters further argue
that EPA later relied on that holding to defend its decision to set a
primary NAAQS for ozone based solely on direct health effects of ozone.
Citing, EPA Pet'n for Rehearing, Am. Trucking Ass'n v. EPA, No. 97-1440
(DC Cir. June 28, 1999) (``ATA I'') (arguing that the primary NAAQS
should be set through consideration of only ``direct adverse effects on
public health, and not indirect, allegedly beneficial effects.'')
The NRDC case is not contrary to EPA's endangerment finding. In
NRDC, petitioner American Iron and Steel Institute argued that EPA had
to consider the costs of health consequences that might arise from
increased unemployment. The court ruled that, ``[c]onsideration of
costs associated with alleged health risks from unemployment would be
flatly inconsistent with the statute, legislative history and case law
on this point.'' 902 F.2d at 973. The cases cited by the court in
support of its decision all hold that EPA may not consider economic or
technological feasibility in establishing a NAAQS. The NRDC decision
does not establish a precedent that the CAA prohibits EPA from
considering indirect health effects as a public health issue rather
than a public welfare issue.
EPA also believes reliance on the Agency's petition for rehearing
in noted above is misplaced. In that case, EPA did not argue that
indirect beneficial health effects were not public health issues.
Instead EPA argued that under the CAA, it did not have to consider such
indirect beneficial health effects of an air pollutant when setting the
health based primary NAAQS. EPA was interpreting the NAAQS standard
setting provisions of CAA section 109, and argued that they were
intended to address only certain public health impacts, those that were
adverse, and were not intended to address indirect, beneficial public
health impacts. The issue in the case was not whether indirect health
effects are relevant for purposes of making an endangerment decision
concerning public health, but rather whether EPA must consider such
beneficial health effects in establishing a primary NAAQS under CAA
section 109. EPA's interpretation of CAA section 109 was rejected in
ATA v. EPA, 175 F.3d at 1027 (1999) reh'g granted in part and denied in
part, 195 F.3d at 4 (DC Cir. 1999). The court made it clear that the
potential indirect beneficial impact of ambient ozone on public health
from screening UVB rays needed to be considered when setting the NAAQS
to protect public health. As discussed above, EPA has done just that as
noted above in the UV-B context. Moreover, as discussed in Section II
of these Findings, EPA is doing that here as well (e.g., considering
any benefits from reduced cold weather related deaths).
ii. EPA's Treatment and Balancing of Heat- vs. Cold-Related Public
Health Risks Was Reasonable
A number of public commenters maintain that the risk of heat waves
in the future will be modulated by adaptive measures. The Administrator
is aware of the potential benefits of adaptation in reducing heat-
related morbidity and mortality and recognizes most heat-related deaths
are preventable. Nonetheless, the Administrator notes the assessment
literature \30\ indicates heat is the leading weather-related killer in
the United States even though countermeasures have been employed in
many vulnerable areas. Given projections for heat waves of greater
frequency, magnitude, and duration coupled with a growing population of
older adults (among the most vulnerable groups to this hazard), the
risk of adverse health outcomes from heat waves is expected to
increase. Intervention and response measures could certainly reduce the
risk, but as we have noted, the need to adapt supports an increase in
risk or endangerment. For a general discussion about EPA's treatment of
adaptation see Section III.C of these Findings.
---------------------------------------------------------------------------
\30\ Karl et al. (2009).
---------------------------------------------------------------------------
Several commenters also suggest cold-related mortality will
decrease more than heat-related mortality will increase, which
indicates a net reduction in temperature-related mortality. Some
commenters point to research suggesting migration to warmer climates
has contributed to the increased longevity of some Americans, implying
climate warming will have benefits for health. The Administrator is
very clear that the exact balance of how heat- versus cold-related
mortality will change in the future is uncertain; however, the
assessment literature points to evidence suggesting that the increased
risk from heat would exceed the decreased risk from cold in a warming
climate. The Administrator does not dispute research indicating the
benefits of migration to a warmer climate and nor that average climate
warming may indeed provide health benefits in some areas. These points
are reflected in the TSD's statement projecting less cold-related
health effects. The Administrator considers these potential warming
benefits independent of the potential negative effects of extreme heat
events which are projected to increase under future climate change
scenarios affecting vulnerable groups and communities.
[[Page 66530]]
iii. EPA Was Reasonable To Find That the Air Quality Impacts of Climate
Change Contribute to the Endangerment of Public Health
Several commenters suggest that air quality effects of climate
change will be addressed through the CAA's NAAQS process, as
implemented by the State Implementation Plans (SIP) and national
regulatory programs. According to these commenters, these programs will
ensure no adverse impact on public health due to climate change. Though
climate change may cause certain air pollutant ambient concentrations
to increase, States will continue to be compelled to meet the
standards. So, while additional measures may be necessary, and result
in increased costs, these commenters assert that, ultimately, public
health will be protected by the continued existence of the NAAQS and
therefore no endangerment with respect to this particular climate
change-related impact will occur. One commenter states that EPA
inappropriately assigns air quality risk to climate change that will be
addressed through other programs. The CAA provides a mechanism to meet
the standards and additional control measures consistent with the CAA
will be adopted in the future, keeping pollution below unhealthy
levels. The commenters state that the fact that NAAQS are in place that
require EPA to fulfill its legal obligation to prevent this particular
form of endangerment to public health.
EPA does have in place NAAQS for ozone, which are premised on the
harmfulness of ozone to public health and welfare. These standards and
their accompanying regulatory regime have helped to reduce the dangers
from ozone in the United States. However, substantial challenges remain
with respect to achieving the air quality protection promised by the
NAAQS for ozone. It is the Administrator's view that these challenges
will be exacerbated by climate change.
In addition, the control measures to achieve attainment with a
NAAQS are a mitigation measure aimed at reducing emissions of ozone
precursors. As discussed in Section III.C of these Findings, EPA is not
considering the impacts of mitigation with respect to future reductions
in emissions of greenhouse gases. For the same reasons, EPA is
reasonably not considering mitigation in the form of the control
measures that will need to be adopted in the future to reduce emissions
of ozone precursors and thereby address the increased ambient ozone
levels that can occur because of climate change.
It is important to note that controls to meet the NAAQS are
typically put in place only after air quality concentrations exceeding
the standard are detected. Furthermore, implementation of controls to
reduce ambient concentrations of pollutants occurs over an extended
time period, ranging from three years to more than twenty years
depending on the pollutant and the seriousness of the nonattainment
problem. Thus, while the CAA provides mechanisms for addressing adverse
health effects and the underlying air quality exacerbation over time,
it will not prevent the adverse impacts in the interim. Given the
serious nature of the health effects at issue--including respiratory
and cardiovascular disease leading to hospital admissions, emergency
department visits, and premature mortality--this increase in adverse
impacts during the time before additional controls can be implemented
is a serious public health concern. Historically, a large segment of
the U.S. population has lived in areas exceeding the NAAQS, despite the
CAA and its implementation efforts. Half of all Americans, 158 million
people, live in counties where air pollution exceeds national health
standards.\31\ Where attainment of the NAAQS is especially difficult,
leading to delays in meeting attainment deadlines, the health effects
of increased ozone due to climate change may be substantial.
---------------------------------------------------------------------------
\31\ U.S. EPA (2008) National Air Quality: Status and Trends
Through 2007. EPA-454/R-08-006, November 2008.
---------------------------------------------------------------------------
It is also important to note that it may not be possible for States
and Tribes to plan accurately for the impacts of climate change in
developing control strategies for nonattainment areas. As noted in the
TSD and EPA's 2009 Interim Assessment report (IA), climate change is
projected to lead to an increase in the variability of weather, and
this may increase peak pollution events including increases in ozone
exceedances. While the modeling studies in the IA all show significant
future changes in meteorological quantities, there is also significant
variability across the simulations in the spatial patterns of these
future changes, making it difficult to select a set of future
meteorological data for planning purposes. At this time, models used to
develop plans to attain the NAAQS do not take potential changes in
future meteorology into consideration. Inability to predict the
frequency and magnitude of such events could lead to an underestimation
of the controls needed to bring areas into attainment, and a prolonged
period during which adverse health impacts continue to occur.
Even in areas that meet the NAAQS currently, air quality may
deteriorate sufficiently to cause adverse health effects for some
individuals. Some at-risk individuals, for example those with
preexisting health conditions or other characteristics which increase
their risk for adverse effects upon exposure to PM or ozone, may
experience health effects at levels below the standard. Current
evidence suggests that there is no threshold for PM or ozone
concentrations below which no effects can be observed. Therefore,
increases in ozone or PM in locations that currently meet the standards
would likely result in additional adverse health effects for some
individuals, even though the pollution increase might not be sufficient
to cause the area to be designated nonattainment. While the NAAQS is
set to protect public health with an adequate margin of safety, it is
recognized that in attainment areas there may be individuals who remain
at greater risk from an increase in ozone levels. The clear risk to the
public from ozone increases in nonattainment areas, in combination with
the risk to some individuals in attainment areas, supports the finding
that overall the public health is endangered by increases in ozone
resulting from climate change.
Finally, it is also important to note that not all air pollution
events are subject to CAA controls under the NAAQS implementation
provisions. ``Exceptional events'' are events for which the normal
planning and regulatory process established by the CAA is not
appropriate (72 FR 13561). Emissions from some events, including some
wildfires, are not reasonably controllable or preventable. Such
emissions, however, can adversely impact public health and welfare and
are expected to increase due to climate change. As described in the
TSD, PM emissions from wildfires can contribute to acute and chronic
illnesses of the respiratory system, particularly in children,
including pneumonia, upper respiratory diseases, asthma and chronic
obstructive pulmonary disease. The IPCC (Field et al., 2007) reported
with very high confidence that in North America, disturbances like
wildfires are increasing and are likely to intensify in a warmer future
with drier soils and longer growing seasons.
2. The Air Pollution Is Reasonably Anticipated to Endanger Public
Welfare
The Administrator also finds that the well-mixed greenhouse gas air
pollution may reasonably be anticipated to
[[Page 66531]]
endanger public welfare, both for current and future generations.
As with public health, the Administrator considered the multiple
pathways in which the greenhouse gas air pollution and resultant
climate change affect climate-sensitive sectors, and the impact this
may have on public welfare. These sectors include food production and
agriculture; forestry; water resources; sea level rise and coastal
areas; energy, infrastructure, and settlements; and ecosystems and
wildlife. The Administrator also considered impacts on the U.S.
population from climate change effects occurring outside of the United
States, such as national security concerns for the United States that
may arise as a result of climate change impacts in other regions of the
world. The Administrator examined each climate-sensitive sector
individually, informed by the summary of the scientific assessments
contained in the TSD, and the full record before EPA, and weighed the
extent to which the risks and impacts within each sector support or do
not support a positive endangerment finding in her judgment. The
Administer then viewed the full weight of evidence looking across all
sectors to reach her decision regarding endangerment to public welfare.
a. Food Production and Agriculture
Food production and agriculture within the United States is a
sector that will be affected by the combined effects of elevated carbon
dioxide concentrations and associated climate change. The Administrator
considered how these effects, both adverse and beneficial, are
affecting the agricultural sector now and in the future, and over
different regions of the United States, taking into account that
different regions of the country specialize in different agricultural
products with varying degrees of sensitivity and vulnerability to
elevated carbon dioxide levels and associated climate change.
Elevated carbon dioxide concentrations can have a stimulatory
effect on grain and oilseed crop yield, as may modest temperature
increases and a longer growing season that results. A report under the
USGCRP concluded that, with increased carbon dioxide and temperature,
the life cycle of grain and oilseed crops will likely progress more
rapidly. However, such beneficial influences need to be considered in
light of various other effects. For example, the literature indicates
that elevated carbon dioxide concentrations may also enhance pest and
weed growth. Pests and weeds can reduce crop yields, cause economic
losses to farmers, and require management control options. How climate
change (elevated carbon dioxide, increased temperatures, altered
precipitation patterns, and changes in the frequency and intensity of
extreme events) may affect the prevalence of pests and weeds is an
issue of concern for food production and the agricultural sector.
Research on the combined effects of elevated carbon dioxide and climate
change on pests, weeds, and disease is still limited. In addition,
higher temperature increases, changing precipitation patterns and
variability, and any increases in ground-level ozone induced by higher
temperatures, can work to counteract any direct stimulatory carbon
dioxide effect, as well as lead to their own adverse impacts. There may
be large regional variability in the response of food production and
agriculture to climate change.
For grain and oilseed crop yields, there is support for the view
that in the near term climate change may have a beneficial effect,
largely through increased temperature and increased carbon dioxide
levels. However there are also factors noted above, some of which are
less well studied and understood, which would tend to offset any near
term benefit, leaving significant uncertainty about the actual
magnitude of any overall benefit. The USGCRP report also concluded that
as temperature rises, these crops will increasingly begin to experience
failure, especially if climate variability increases and precipitation
lessens or becomes more variable.
A key uncertainty is how human-induced climate change may affect
the intensity and frequency of extreme weather events such as droughts
and heavy storms. These events have the potential to have serious
negative impact on U.S. food production and agriculture, but are not
always taken into account in studies that examine how average
conditions may change as a result of carbon dioxide and temperature
increases. Changing precipitation patterns, in addition to increasing
temperatures and longer growing seasons, can change the demand for
irrigation requirements, potentially increasing irrigation demand.
Another key uncertainty concerns the many horticultural crops
(e.g., tomatoes, onions, fruits), which make up roughly 40 percent of
total crop value in the United States. There is relatively little
information on their response to carbon dioxide, and few crop
simulation models, but according to the literature, they are very
likely to be more sensitive to the various effects of climate change
than grain and oilseed crops.
With respect to livestock, higher temperatures will very likely
reduce livestock production during the summer season in some areas, but
these losses will very likely be partially offset by warmer
temperatures during the winter season. The impact on livestock
productivity due to increased variability in weather patterns will
likely be far greater than effects associated with the average change
in climatic conditions. Cold-water fisheries will likely be negatively
affected; warm-water fisheries will generally benefit; and the results
for cool-water fisheries will be mixed, with gains in the northern and
losses in the southern portions of ranges.
Finally, with respect to irrigation requirements, the adverse
impacts of climate change on irrigation water requirements may be
significant.
There is support for the view that there may be a benefit in the
near term in the crop yield for certain crops. This potential benefit
is subject to significant uncertainty, however, given the offsetting
impact on the yield of these crops from a variety of other climate
change impacts that are less well understood and more variable. Any
potential net benefit is expected to change to a disbenefit in the
longer term. In addition, there is clear risk that the sensitivity of a
major segment of the total crop market, the horticultural sector, may
lead to adverse affects from climate change. With respect to livestock
production and irrigation requirements, climate change is likely to
have adverse effects in both the near and long terms. The impact on
fisheries varies, and would appear to be best viewed as neutral
overall.
There is a potential for a net benefit in the near term for certain
crops, but there is significant uncertainty about whether this benefit
will be achieved given the various potential adverse impacts of climate
change on crop yield, such as the increasing risk of extreme weather
events. Other aspects of this sector are expected to be adversely
affected by climate change, including livestock management and
irrigation requirements, and there is a risk of adverse effect on a
large segment of the total crop market. For the near term, the concern
over the potential for adverse effects in certain parts of the
agriculture sector appears generally comparable to the potential for
benefits for certain crops.
However, considering the trend over near- and long-term future
conditions, the Administrator finds that the body of evidence points
towards increasing risk
[[Page 66532]]
of net adverse impacts on U.S. food production and agriculture, with
the potential for significant disruptions and crop failure in the
future.
b. Forestry
The factors that the Administrator considered for the U.S. forest
sector are similar to those for food production and agriculture. There
is the potential for beneficial effects due to elevated concentrations
of carbon dioxide and increased temperature, as well as the potential
for adverse effects from increasing temperatures, changing
precipitation patterns, increased insects and disease, and the
potential for more frequent and severe extreme weather events. The
potential beneficial effects are better understood and studied, and are
limited to certain areas of the country and types of forests. The
adverse effects are less certain, more variable, and also include some
of the most serious adverse effects such as increased wildfire,
drought, and major losses from insects and disease. As with food
production and agriculture, the judgment to be made is largely a
qualitative one, balancing impacts that vary in certainty and
magnitude, with the end result being a judgment as to the overall
direction and general level of concern.
According to the underlying science assessment reports, climate
change has very likely increased the size and number of wildfires,
insect outbreaks, and tree mortality in the Interior West, the
Southwest, and Alaska, and will continue to do so. Rising atmospheric
carbon dioxide levels will very likely increase photosynthesis for
forests, but the increased photosynthesis will likely only increase
wood production in young forests on fertile soils. Nitrogen deposition
and warmer temperatures have very likely increased forest growth where
water is not limiting and will continue to do so in the near future.
An increased frequency of disturbance (such as drought, storms,
insect-outbreaks, and wildfire) is at least as important to forest
ecosystem function as incremental changes in temperature,
precipitation, atmospheric carbon dioxide, nitrogen deposition, and
ozone pollution. Disturbances partially or completely change forest
ecosystem structure and species composition, cause short-term
productivity and carbon storage loss, allow better opportunities for
invasive alien species to become established, and command more public
and management attention and resources. The combined effects of
expected increased temperature, carbon dioxide, nitrogen deposition,
ozone, and forest disturbance on soil processes and soil carbon storage
remain unclear.
Precipitation and weather extremes are key to many forestry
impacts, accounting for part of the regional variability in forest
response. If existing trends in precipitation continue, it is expected
that forest productivity will likely decrease in the Interior West, the
Southwest, eastern portions of the Southeast, and Alaska, and that
forest productivity will likely increase in the northeastern United
States, the Lake States, and in western portions of the Southeast. An
increase in drought events will very likely reduce forest productivity
wherever such events occur.
Changes in disturbance patterns are expected to have a substantial
impact on overall gains or losses. More prevalent wildfire disturbances
have recently been observed in the United States. Wildfires and
droughts, among other extreme events (e.g., hurricanes) that can cause
forest damage, pose the largest threats over time to forest ecosystems.
For the near term, the Administrator believes the beneficial impact
on forest growth and productivity in certain parts of the country from
climate change to be more than offset by the clear risk from the more
significant and serious adverse effects from the observed increases in
wildfires, combined with the adverse impacts on growth and productivity
in other areas of the country and the serious risks from the spread of
destructive pests and disease. Increased wildfires can also increase
particulate matter and thus create public health concerns as well. For
the longer term, the Administrator views the risk from adverse effects
to increase over time, such that overall climate change presents
serious adverse risks for forest productivity. The Administrator
therefore finds there is compelling reason to find that the greenhouse
gas air pollution endangers U.S. forestry in both the near and long
term, with the support for a positive endangerment finding only
increasing as one considers expected future conditions in which
temperatures continue to rise.
c. Water Resources
The sensitivity of water resources to climate change is very
important given the increasing demand for adequate water supplies and
services for agricultural, municipal, and energy and industrial uses,
and the current strains on this resource in many parts of the country.
According to the assessment literature, climate change has already
altered, and will likely continue to alter, the water cycle, affecting
where, when, and how much water is available for all uses. With higher
temperatures, the water-holding capacity of the atmosphere and
evaporation into the atmosphere increase, and this favors increased
climate variability, with more intense precipitation and more droughts.
Climate change is causing and will increasingly cause shrinking
snowpack induced by increasing temperature. In the western United
States, there is already well-documented evidence of shrinking snowpack
due to warming. Earlier meltings, with increased runoff in the winter
and early spring, increase flood concerns and also result in
substantially decreased summer flows. This pattern of reduced snowpack
and changes to the flow regime pose very serious risks to major
population regions, such as California, that rely on snowmelt-dominated
watersheds for their water supply. While increased precipitation is
expected to increase water flow levels in some eastern areas, this may
be tempered by increased variability in the precipitation and the
accompanying increased risk of floods and other concerns such as water
pollution.
Warmer temperatures and decreasing precipitation in other parts of
the country, such as the Southwest, can sustain and amplify drought
impacts. Although drought has been more frequent and intense in the
western part of the United States, the East is also vulnerable to
droughts and attendant reductions in water supply, changes in water
quality and ecosystem function, and challenges in allocation. The
stress on water supplies on islands is expected to increase.
The impact of climate change on groundwater as a water supply is
regionally variable; efforts to offset declining surface water
availability due to increasing precipitation variability may be
hampered by the fact that groundwater recharge will decrease
considerably in some already water-stressed regions. In coastal areas,
the increased salinization from intrusion of salt water is projected to
have negative effects on the supply of fresh water.
Climate change is expected to have adverse effects on water
quality. The IPCC concluded with high confidence that higher water
temperatures, increased precipitation intensity, and longer periods of
low flows exacerbate many forms of water pollution and can impact
ecosystems, human health, and water system reliability and operating
costs. These changes will also exacerbate many forms of water
pollution, potentially making attainment of water quality goals more
[[Page 66533]]
difficult. Water pollutants of concern that are particularly relevant
to climate change effects include sediment, nutrients, organic matter,
pathogens, pesticides, salt, and thermal pollution. As waters become
warmer, the aquatic life they now support will be replaced by other
species better adapted to warmer water. In the long term, warmer water,
changing flows, and decreased water quality may result in deterioration
of aquatic ecosystems.
Climate change will likely further constrain already over-allocated
water resources in some regions of the United States, increasing
competition among agricultural, municipal, industrial, and ecological
uses. Although water management practices in the United States are
generally advanced, particularly in the West, the reliance on past
conditions as the basis for current and future planning may no longer
be appropriate, as climate change increasingly creates conditions well
outside of historical observations. Increased incidence of extreme
weather and floods may also overwhelm or damage water treatment and
management systems, resulting in water quality impairments. In the
Great Lakes and major river systems, lower water levels are likely to
exacerbate challenges relating to water quality, navigation,
recreation, hydropower generation, water transfers, and bi-national
relationships.
The Administrator finds that the total scientific literature
provides compelling support for finding that greenhouse gas air
pollution endangers the water resources important for public welfare in
the United States, both for current and future generations. The
adequacy of water supplies across large areas of the country is at
serious risk from climate change. Even areas of the country where an
increase in water flow is projected could face water resource problems
from the variability of the supply and water quality problems
associated with precipitation variability, and could face the serious
adverse effects from risks from floods and drought. Climate change is
expected to adversely affect water quality. There is an increased risk
of serious adverse effects from extreme events of flooding and drought.
The severity of risks and impacts may only increase over time with
accumulating greenhouse gas concentrations and associated temperature
increases and precipitation changes.
d. Sea Level Rise and Coastal Areas
A large percentage of the U.S. population lives in coastal areas,
which are particularly vulnerable to the risks posed by climate change.
The most vulnerable areas are the Atlantic and Gulf Coasts, the Pacific
Islands, and parts of Alaska.
According to the assessment literature, sea level is rising along
much of the U.S. coast, and the rate of change will very likely
increase in the future, exacerbating the impacts of progressive
inundation, storm-surge flooding, and shoreline erosion. Cities such as
New Orleans, Miami, and New York are particularly at risk, and could
have difficulty coping with the sea level rise projected by the end of
the century under a higher emissions scenario. Population growth and
the rising value of infrastructure increases the vulnerability to
climate variability and future climate change in coastal areas. Adverse
impacts on islands present concerns for Hawaii and the U.S.
territories. Reductions in Arctic sea ice increases extreme coastal
erosion in Alaska, due to the increased exposure of the coastline to
strong wave action. In the Great Lakes, where sea level rise is not a
concern, both extremely high and low water levels resulting from
changes to the hydrological cycle have been damaging and disruptive to
shoreline communities.
Coastal wetland loss is being observed in the United States where
these ecosystems are squeezed between natural and artificial landward
boundaries and rising sea levels. Up to 21 percent of the remaining
coastal wetlands in the U.S. mid-Atlantic region are potentially at
risk of inundation between 2000 and 2100. Coastal habitats will likely
be increasingly stressed by climate change impacts interacting with
development and pollution.
Although increases in mean sea level over the 21st century and
beyond will inundate unprotected, low-lying areas, the most devastating
impacts are likely to be associated with storm surge. Superimposed on
expected rates of sea level rise, projected storm intensity, wave
height, and storm surge suggest more severe coastal flooding and
erosion hazards. Higher sea level provides an elevated base for storm
surges to build upon and diminishes the rate at which low-lying areas
drain, thereby increasing the risk of flooding from rainstorms. In New
York City and Long Island, flooding from a combination of sea level
rise and storm surge could be several meters deep. Projections suggest
that the return period of a 100-year flood event in this area might be
reduced to 19-68 years, on average, by the 2050s, and to 4-60 years by
the 2080s. Additionally, some major urban centers in the United States,
such as areas of New Orleans are situated in low-lying flood plains,
presenting increased risk from storm surges.
The Administrator finds that the most serious risk of adverse
effects is presented by the increased risk of storm surge and flooding
in coastal areas from sea level rise. Current observations of sea level
rise are now contributing to increased risk of storm surge and flooding
in coastal areas, and there is reason to find that these areas are now
endangered by human-induced climate change. The conclusion in the
assessment literature that there is the potential for hurricanes to
become more intense with increasing temperatures (and even some
evidence that Atlantic hurricanes have already become more intense)
reinforces the judgment that coastal communities are now endangered by
human-induced climate change, and may face substantially greater risk
in the future. The Administrator has concluded that even if there is a
low probability of raising the destructive power of hurricanes, this
threat is enough to support a finding that coastal communities are
endangered by greenhouse gas air pollution.
In addition, coastal areas face other adverse impacts from sea
level rise such as shoreline retreat, erosion, wetland loss and other
effects. The increased risk associated with these adverse impacts also
endangers the welfare of current and future generations, with an
increasing risk of greater adverse impacts in the future.
Overall, the evidence on risk of adverse impacts for coastal areas
from sea level rise provides clear support for finding that greenhouse
gas air pollution endangers the welfare of current and future
generations.
e. Energy, Infrastructure and Settlements
The Administrator also considered the impacts of climate change on
energy consumption and production, and on key climate-sensitive aspects
of the nation's infrastructure and settlements.
For the energy sector, the Administrator finds clear evidence that
temperature increases will change heating and cooling demand, and to
varying degrees across the country; however, under current conditions
it is unclear whether or not net demand will increase or decrease.
While the impacts on net energy demand may be viewed as generally
neutral for purposes of making an endangerment determination, climate
change is expected to call for an increase in electricity production,
especially supply for peak demand. The U.S. energy sector, which relies
heavily on water for cooling capacity and
[[Page 66534]]
hydropower, may be adversely impacted by changes to water supply in
reservoirs and other water bodies.
With respect to infrastructure, climate change vulnerabilities of
industry, settlement and society are mainly related to extreme weather
events rather than to gradual climate change. The significance of
gradual climate change, e.g., increases in the mean temperature, lies
mainly in changes in the intensity and frequency of extreme events.
Extreme weather events could threaten U.S. energy infrastructure
(transmission and distribution), transportation infrastructure (roads,
bridges, airports and seaports), water infrastructure, and other built
aspects of human settlements. Moreover, soil subsidence caused by the
melting of permafrost in the Arctic region is a risk to gas and oil
pipelines, electrical transmission towers, roads, and water systems.
Vulnerabilities for industry, infrastructures, settlements, and society
to climate change are generally greater in certain high-risk locations,
particularly coastal and riverine areas, and areas whose economies are
closely linked with climate-sensitive resources. Additionally,
infrastructures are often connected, meaning that an impact on one can
also affect others.
A significant fraction of U.S. infrastructure is located in coastal
areas. In these locations, rising sea levels are likely to lead to
direct losses (e.g., equipment damage from flooding) as well as
indirect effects such as the costs associated with raising vulnerable
assets to higher levels. Water infrastructure, including drinking water
and wastewater treatment plants, and sewer and storm water management
systems, may be at greater risk of flooding, sea level rise and storm
surge, low flows, saltwater intrusion, and other factors that could
impair performance and damage costly investments.
Within settlements experiencing climate change stressors, certain
parts of the population may be especially vulnerable based on their
circumstances. These include the poor, the elderly, the very young,
those already in poor health, the disabled, those living alone, and/or
indigenous populations dependent on one or a few resources. In Alaska,
indigenous communities are likely to experience disruptive impacts,
including shifts in the range or abundance of wild species crucial to
their livelihoods and well-being.
Overall, the evidence strongly supports the view that climate
change presents risks of serious adverse impacts on public welfare from
the risk to energy production and distribution as well as risks to
infrastructure and settlements.
f. Ecosystems and Wildlife
The Administrator considered the impacts of climate change on
ecosystems and wildlife and the services they provide. The
Administrator finds clear evidence that climate change is exerting
major influences on natural environments and biodiversity, and these
influences are generally expected to grow with increased warming.
Observed changes in the life cycles of plants and animals include
shifts in habitat ranges, timing of migration patterns, and changes in
reproductive timing and behavior.
The underlying assessment literature finds with high confidence
that substantial changes in the structure and functioning of
terrestrial ecosystems are very likely to occur with a global warming
greater than 2 to 3 [deg]C above pre-industrial levels, with
predominantly negative consequences for biodiversity and the
provisioning of ecosystem goods and services. With global average
temperature changes above 2 [deg]C, many terrestrial, freshwater, and
marine species (particularly endemic species) are at a far greater risk
of extinction than in the geological past. Climate change and ocean
acidification will likely impair a wide range of planktonic and other
marine calcifiers such as corals. Even without ocean acidification
effects, increases in sea surface temperature of about 1-3 [deg]C are
projected to result in more frequent coral bleaching events and
widespread mortality. In the Arctic, wildlife faces great challenges
from the effects of climatic warming, as projected reductions in sea
ice will drastically shrink marine habitat for polar bears, ice-
inhabiting seals, and other animals.
Some common forest types are projected to expand, such as oak-
hickory, while others are projected to contract, such as maple-beech-
birch. Still others, such as spruce-fir, are likely to disappear from
the contiguous United States. Changes in plant species composition in
response to climate change can increase ecosystem vulnerability to
other disturbances, including wildfires and biological invasion.
Disturbances such as wildfires and insect outbreaks are increasing in
the United States and are likely to intensify in a warmer future with
warmer winters, drier soils and longer growing seasons. The areal
extent of drought-limited ecosystems is projected to increase 11
percent per [deg]C warming in the United States. In California,
temperature increases greater than 2 [deg]C may lead to conversion of
shrubland into desert and grassland ecosystems and evergreen conifer
forests into mixed deciduous forests. Greater intensity of extreme
events may alter disturbance regimes in coastal ecosystems leading to
changes in diversity and ecosystem functioning. Species inhabiting salt
marshes, mangroves, and coral reefs are likely to be particularly
vulnerable to these effects.
The Administrator finds that the total scientific record provides
compelling support for finding that the greenhouse gas air pollution
leads to predominantly negative consequences for biodiversity and the
provisioning of ecosystem goods and services for ecosystems and
wildlife important for public welfare in the U.S., both for current and
future generations. The severity of risks and impacts may only increase
over time with accumulating greenhouse gas concentrations and
associated temperature increases and precipitation changes.
g. Summary of the Administrator's Finding of Endangerment to Public
Welfare
The Administrator has considered how elevated concentrations of the
well-mixed greenhouse gases and associated climate change affect public
welfare by evaluating numerous and far-ranging risks to food production
and agriculture, forestry, water resources, sea level rise and coastal
areas, energy, infrastructure, and settlements, and ecosystems and
wildlife. For each of these sectors, the evidence provides support for
a finding of endangerment to public welfare. The evidence concerning
adverse impacts in the areas of water resources and sea level rise and
coastal areas provide the clearest and strongest support for an
endangerment finding, both for current and future generations. Strong
support is also found in the evidence concerning infrastructure and
settlements, as well ecosystems and wildlife. Across the sectors, the
potential serious adverse impacts of extreme events, such as wildfires,
flooding, drought, and extreme weather conditions provide strong
support for such a finding.
Water resources across large areas of the country are at serious
risk from climate change, with effects on water supplies, water
quality, and adverse effects from extreme events such as floods and
droughts. Even areas of the country where an increase in water flow is
projected could face water resource problems from the supply and water
quality problems associated with temperature increases and
precipitation variability, and could face the increased risk of serious
adverse effects from extreme events, such as floods and
[[Page 66535]]
drought. The severity of risks and impacts is likely to increase over
time with accumulating greenhouse gas concentrations and associated
temperature increases and precipitation changes.
Overall, the evidence on risk of adverse impacts for coastal areas
provides clear support for a finding that greenhouse gas air pollution
endangers the welfare of current and future generations. The most
serious potential adverse effects are the increased risk of storm surge
and flooding in coastal areas from sea level rise and more intense
storms. Observed sea level rise is already increasing the risk of storm
surge and flooding in some coastal areas. The conclusion in the
assessment literature that there is the potential for hurricanes to
become more intense (and even some evidence that Atlantic hurricanes
have already become more intense) reinforces the judgment that coastal
communities are now endangered by human-induced climate change, and may
face substantially greater risk in the future. Even if there is a low
probability of increasing the destructive power of hurricanes, this
threat is enough to support a finding that coastal communities are
endangered by greenhouse gas air pollution. In addition, coastal areas
face other adverse impacts from sea level rise such as land loss due to
inundation, erosion, wetland submergence, and habitat loss. The
increased risk associated with these adverse impacts also endangers
public welfare, with an increasing risk of greater adverse impacts in
the future.
Strong support for an endangerment finding is also found in the
evidence concerning energy, infrastructure, and settlements, as well
ecosystems and wildlife. While the impacts on net energy demand may be
viewed as generally neutral for purposes of making an endangerment
determination, climate change is expected to result in an increase in
electricity production, especially to meet peak demand. This increase
may be exacerbated by the potential for adverse impacts from climate
change on hydropower resources as well as the potential risk of serious
adverse effects on energy infrastructure from extreme events. Changes
in extreme weather events threaten energy, transportation, and water
resource infrastructure. Vulnerabilities of industry, infrastructure,
and settlements to climate change are generally greater in high-risk
locations, particularly coastal and riverine areas, and areas whose
economies are closely linked with climate-sensitive resources. Climate
change will likely interact with and possibly exacerbate ongoing
environmental change and environmental pressures in settlements,
particularly in Alaska where indigenous communities are facing major
environmental and cultural impacts on their historic lifestyles. Over
the 21st century, changes in climate will cause some species to shift
north and to higher elevations and fundamentally rearrange U.S.
ecosystems. Differential capacities for range shifts and constraints
from development, habitat fragmentation, invasive species, and broken
ecological connections will likely alter ecosystem structure, function,
and services, leading to predominantly negative consequences for
biodiversity and the provision of ecosystem goods and services.
With respect to food production and agriculture, there is a
potential for a net benefit in the near term for certain crops, but
there is significant uncertainty about whether this benefit will be
achieved given the various potential adverse impacts of climate change
on crop yield, such as the increasing risk of extreme weather events.
Other aspects of this sector may be adversely affected by climate
change, including livestock management and irrigation requirements, and
there is a risk of adverse effect on a large segment of the total crop
market. For the near term, the concern over the potential for adverse
effects in certain parts of the agriculture sector appears generally
comparable to the potential for benefits for certain crops. However,
the body of evidence points towards increasing risk of net adverse
impacts on U.S. food production and agriculture over time, with the
potential for significant disruptions and crop failure in the future.
For the near term, the Administrator finds the beneficial impact on
forest growth and productivity in certain parts of the country from
elevated carbon dioxide concentrations and temperature increases to
date is offset by the clear risk from the observed increases in
wildfires, combined with risks from the spread of destructive pests and
disease. For the longer term, the risk from adverse effects increases
over time, such that overall climate change presents serious adverse
risks for forest productivity. There is compelling reason to find that
the support for a positive endangerment finding increases as one
considers expected future conditions where temperatures continue to
rise.
Looking across all of the sectors discussed above, the evidence
provides compelling support for finding that greenhouse gas air
pollution endangers the public welfare of both current and future
generations. The risk and the severity of adverse impacts on public
welfare are expected to increase over time.
h. Impacts in Other World Regions That Can Affect the U.S Population
While the finding of endangerment to public health and welfare
discussed above is based on impacts in the United States, the
Administrator also considered how human-induced climate change in other
regions of the world may in turn affect public welfare in the United
States. According to the USGCRP report of June 2009 and other sources,
climate change impacts in certain regions of the world may exacerbate
problems that raise humanitarian, trade, and national security issues
for the United States.\32\ The IPCC identifies the most vulnerable
world regions as the Arctic, because of the effects of high rates of
projected warming on natural systems; Africa, especially the sub-
Saharan region, because of current low adaptive capacity as well as
climate change; small islands, due to high exposure of population and
infrastructure to risk of sea-level rise and increased storm surge; and
Asian mega-deltas, such as the Ganges-Brahmaputra and the Zhujiang, due
to large populations and high exposure to sea level rise, storm surge,
and river flooding. Climate change has been described as a potential
threat multiplier with regard to national security issues.
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\32\ ``In an increasingly interdependent world, U.S.
vulnerability to climate change is linked to the fates of other
nations. For example, conflicts or mass migrations of people
resulting from food scarcity and other resource limits, health
impacts or environmental stresses in other parts of the world could
threaten U.S. national security.'' (Karl et al., 2009).
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The Administrator acknowledges these kinds of risks do not readily
lend themselves to precise analyses or future projections. However,
given the unavoidable global nature of the climate change problem, it
is appropriate and prudent to consider how impacts in other world
regions may present risks to the U.S. population. Because human-induced
climate change has the potential to aggravate natural resource, trade,
and humanitarian issues in other world regions, which in turn may
contribute to the endangerment of public welfare in the United States,
this provides additional support for the Administrator's finding that
the greenhouse gas air pollution is reasonably anticipated to endanger
the public welfare of current and future
[[Page 66536]]
generations of the United States population.
i. Summary of Key Public Comments on Endangerment to Public Welfare
Several public commenters point out the anticipated benefits that
increasing carbon dioxide levels and temperatures will have on
agricultural crops. In addition, commenters note how U.S. agricultural
productivity, in particular, has been steadily rising over the last 100
years. Responses to major comments are found here and more detailed
responses are found in the Response to Comments document.
The Administrator acknowledges that plants including agricultural
crops respond to carbon dioxide positively based on numerous well-
documented studies. However, previous assessments of food production
and agriculture have been modified to highlight increasing
vulnerability, stress, and adverse impacts from climate change over
time, based on improvements in the understanding of plant physiology,
concern over impacts on plant pests and pathogens, and the implications
of changes in average temperatures for temperature extremes and for
changes in the patterns of precipitation and evaporation. While it is
still the case today and for the next few years that climate change
benefits agriculture in some places and harms them in others, the
Administrator considers that the far larger temperature increases
expected over coming decades and beyond on the ``business as usual''
trajectory will put significant stresses on agriculture and land
resources in all regions of the United States. The Administrator
prudently considers increased climate variability associated with a
warming climate, which may overwhelm the positive plant responses from
elevated carbon dioxide over time. Further, the effects of climate
change on weeds, insect pests, and pathogens are recognized as key
factors in determining plant damage in future decades. The
Administrator also notes that scientific literature clearly supports
the finding that drought frequency and severity are projected to
increase in the future over much of the United States, which will
likely reduce crop yields because of excesses or deficits of water.
Vulnerability to extended drought, according to IPCC, has been
documented as already increasing across North America. Further, based
on review of the assessment literature, the Administrator considers
multiple stresses, such as limited availability of water resources,
loss of biodiversity, and air pollution, which are likely to increase
sensitivity and reduce resilience in the agricultural sector to climate
change over time.
Similar to food production and agriculture, public commenters often
noted that forest productivity is projected to increase in the coming
years due to the direct stimulatory effect of carbon dioxide on plant
growth combined with warmer temperatures and thus extended growing
seasons. The Administrator notes this phenomenon has been well
documented by numerous studies but recognizes that increased
productivity will be associated with significant variation at local and
regional scales. The Administrator considers that climate strongly
influences forest productivity and composition, and the frequency and
magnitude of disturbances that impact forests. Based on the most recent
IPCC assessment of the scientific literature, several recent studies
confirm previous findings that temperature and precipitation changes in
future decades will modify, and often limit, direct carbon dioxide
effects on plants. For example, increased temperatures may reduce
carbon dioxide effects indirectly, by increasing water demand. The
Administrator also considers that new research more firmly establishes
the negative impacts of increased climate variability. Projected
changes in the frequency and severity of extreme climate events have
significant consequences for forestry production and amplify existing
stresses to land resources in the future.
Several public commenters maintain that wildfires are primarily the
result of natural climatic factors and not climate change and dispute
that they are or will increase in the future. The Administrator notes
the scientific literature and assessment reports provide several lines
of evidence that suggest wildfires will likely increase in frequency
over the next several decades because of climate warming. Wildfires and
droughts, among other extreme events (e.g., hurricanes) that cause
forest damage, pose the largest threats over time to forest ecosystems.
The assessment literature suggests that large, stand-replacing
wildfires will likely increase in frequency over the next several
decades because of climate warming and general climate warming
encourages wildfires by extending the summer period that dries fuels,
promoting easier ignition and faster spread. Furthermore, current
climate modeling studies suggest that increased temperatures and longer
growing seasons will elevate wildfire risk in connection with increased
aridity.
V. The Administrator's Finding That Emissions of Greenhouse Gases From
CAA Section 202(a) Sources Cause or Contribute to the Endangerment of
Public Health and Welfare
As discussed in Section IV.A of these Findings, the Administrator
is defining the air pollution for purposes of the endangerment finding
to be the elevated concentration of well-mixed greenhouse gases in the
atmosphere. The second step of the two-part endangerment test is for
the Administrator to determine whether the emission of any air
pollutant emitted from new motor vehicles cause or contribute to this
air pollution. This is referred to as the cause or contribute finding,
and is the second finding by the Administrator in this action.
Section V.A of these Findings describes the Administrator's
definition and scope of the air pollutant ``well-mixed greenhouse
gases.'' Section V.B of these Findings puts forth the Administrator's
finding that emissions of well-mixed greenhouse gases from new motor
vehicles contribute to the air pollution which is reasonably
anticipated to endanger public health and welfare. Section V.C of these
Findings provides responses to some of the key comments on these
issues. See Response to Comments document Volume 10 for responses to
other significant comments on the cause or contribute finding. More
detailed emissions data summarized in the discussion below can be found
in Appendix B of the TSD.
A. The Administrator's Definition of the ``Air Pollutant''
As discussed in the Proposed Findings, to help appreciate the
distinction between air pollution and air pollutant, the air pollution
can be thought of as the total, cumulative stock in the atmosphere,
while the air pollutant, can be thought of as the flow that changes the
size of the total stock. Given this relationship, it is not surprising
that the Administrator is defining the air pollutant similar to the air
pollution; while the air pollution is the concentration (e.g., stock)
of the well-mixed greenhouse gases in the atmosphere, the air pollutant
is the same combined grouping of the well-mixed greenhouse gases, the
emissions of which are analyzed for contribution (e.g., the flow into
the stock).
Thus, the Administrator is defining the air pollutant as the
aggregate group of the same six long-lived and directly-emitted
greenhouse gases: Carbon dioxide, methane, nitrous oxide,
hydrofluorocarbons, perfluorocarbons,
[[Page 66537]]
and sulfur hexafluoride. As noted above, this definition of a single
air pollutant made up of these well-mixed greenhouse gases is similar
to definitions of other air pollutants that are comprised of substances
that share common attributes with similar effects on public health or
welfare (e.g., particulate matter and volatile organic compounds).
The common attributes shared by these six greenhouse gases are
discussed in detail in Section IV.A of these Findings, where the
Administrator defined the ``air pollution'' for purposes of the
endangerment finding. These same common attributes support the
Administrator grouping these six greenhouse gases for purposes of
defining a single air pollutant as well. These attributes include the
fact that they are all greenhouse gases that are directly emitted
(i.e., they are not formed through secondary processes in the
atmosphere from precursor emissions); they are sufficiently long-lived
in the atmosphere such that, once emitted, concentrations of each gas
become well mixed throughout the entire global atmosphere; and they
exert a climate warming effect by trapping outgoing, infrared heat that
would otherwise escape to space. Moreover, the radiative forcing effect
of these six greenhouse gases is well understood.
Furthermore, these six greenhouse gases are currently the common
focus of climate science and policy. For example, the UNFCCC, signed
and ratified by the U.S. in 1992, requires its signatories to
``develop, periodically update, publish and make available * * *
national inventories of anthropogenic emissions by sources and removals
by sinks of all greenhouse gases not controlled by the Montreal
Protocol \33\, using comparable methodologies * * * '' \34\ To date,
the focus of UNFCCC actions and discussions has been on the six
greenhouse gases that are the same focus of these findings. As a Party
to the UNFCCC, EPA annually submits the Inventory of U.S. Greenhouse
Gas Emissions and Sinks to the Convention, which reports on national
emissions of anthropogenic emissions of the well-mixed greenhouse
gases. International discussions about a post-Kyoto agreement also
focus on the well-mixed greenhouse gases.
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\33\ The Montreal Protocol covers ozone-depleting substances
which may also share physical attributes of the six key greenhouse
gases in this action, but they do not share other attributes such as
being the focus of climate science and policy. See section * * *.
\34\ UNFCCC Art. 4.1(b).
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As noted above, grouping of many substances with common attributes
as a single pollutant is common practice under the CAA. Thus, doing so
here is not novel. Indeed CAA section 302(g) defines air pollutant as
``any air pollutant agent or combination of such agents, * * * '' CAA
Sec. 302(g) (emphasis added). Thus, it is clear that the term ``air
pollutant'' is not limited to individual chemical compounds. In
determining that greenhouse gases are within the scope of this
definition, the Supreme Court described section 302(g) as a
``sweeping'' and ``capacious'' definition that unambiguously included
greenhouse gases, that are ``unquestionably `agents' of air
pollution.'' Massachusetts v. EPA, 549 U.S. at 528, 532, 529 n.26.
Although the Court did not interpret the term ``combination of'' air
pollution agents, there is no reason this phrase would be interpreted
any less broadly. Congress used the term ``any'', and did not qualify
the kind of combinations that the agency could define as a single air
pollutant. Congress provided EPA broad discretion to determine
appropriate combinations of compounds that should be treated as a singe
air pollutant.\35\
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\35\ Indeed, the greenhouse gases hydrofluorocarbons and
perfluorocarbons each are already a combination of multiple
compounds.
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For the same reasons discussed in Section IV.A above, at this time,
only carbon dioxide, methane, nitrous oxide, hydrofluorocarbons,
perfluorocarbons, and sulfur hexafluoride share all of these common
attributes and thus they are the only substances that the Administrator
finds to meet the definition of ``well-mixed greenhouse gas'' at this
time.\36\ Also as noted above, if in the future other substances are
shown to meet the same criteria they may be added to the definition of
this single air pollutant.
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\36\ The term ``well-mixed greenhouse gases'' is based on one of
the shared attributes discussed above--these greenhouse gases are
sufficiently long-lived in the atmosphere such that, once emitted,
concentrations of each gas become well mixed throughout the entire
global atmosphere. Defining the air pollutant to be the combination
of these six well-mixed greenhouse gases is based in part on this
attribute--after the gases are emitted, they are sufficiently long-
lived in the atmosphere to become well mixed as part of the air
pollution.
---------------------------------------------------------------------------
The Administrator is aware that CAA section 202(a) source
categories do not emit all of the substances meeting the definition of
well-mixed greenhouse gases. But that does not change the fact that all
of these greenhouse gases share the attributes that make grouping them
as a single air pollutant reasonable. As discussed further below, the
reasonableness of this grouping does not turn on the particular source
category being evaluated in a contribution finding.
B. The Administrator's Finding Regarding Whether Emissions of the Air
Pollutant From Section 202(a) Source Categories Cause or Contribute to
the Air Pollution That May Be Reasonably Anticipated To Endanger Public
Health and Welfare
The Administrator finds that emissions of the well-mixed greenhouse
gases from new motor vehicles contribute to the air pollution that may
reasonably be anticipated to endanger public health and welfare. This
contribution finding is for all of the CAA section 202(a) source
categories and the Administrator considered emissions from all of these
source categories. The relevant mobile sources under CAA section 202
(a)(1) are ``any class or classes of new motor vehicles or new motor
vehicle engines, * * *.'' CAA section 202(a)(1) (emphasis added). The
new motor vehicles and new motor vehicle engines (hereinafter ``CAA
section 202(a) source categories'') addressed are: Passenger cars,
light-duty trucks, motorcycles, buses, and medium and heavy-duty
trucks. Detailed combined greenhouse gas emissions data for CAA section
202(a) source categories are presented in Appendix B of the TSD.\37\
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\37\ For section 202(a) source categories, only the
hydrofluorocarbon emissions related to passenger compartment cooling
are included. Emissions from refrigeration units that may be
attached to trucks are considered emissions from nonroad engines
under CAA section 213.
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The Administrator reached her decision after reviewing emissions
data on the contribution of CAA section 202(a) source categories
relative to both global greenhouse gas emissions and U.S. greenhouse
gas emissions. Given that CAA section 202(a) source categories are
responsible for about 4 percent of total global greenhouse gas
emissions, and for just over 23 percent of total U.S. greenhouse gas
emissions, the Administrator finds that both of these comparisons,
independently and together, support a finding that CAA section 202(a)
source categories contribute to the air pollution that may be
reasonably anticipated to endanger public health and welfare. The
Administrator is not placing primary weight on either approach; rather
she finds that both approaches clearly establish that emissions of the
well-mixed greenhouse gases from section 202(a) source categories
contribute to air pollution with may reasonably be anticipated to
endanger public health and welfare. As the Supreme Court noted,
``[j]udged by any standard, U.S.
[[Page 66538]]
motor-vehicle emissions make a meaningful contribution to greenhouse
gas concentrations and hence, * * * to global warming.'' Massachusetts
v. EPA, 549 U.S. at 525.\38\
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\38\ Because the Administrator is defining the air pollutant as
the combination of well-mixed greenhouse gases, she is not issuing a
final contribution finding based on the alternative definition
discussed in the proposed findings (e.g., each greenhouse gas as an
individual air pollutant).
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1. Administrator's Approach in Making This Finding
Section 202(a) of the CAA source categories consist of passenger
cars, light-duty trucks, motorcycles, buses, and heavy- and medium-duty
trucks. As noted in the Proposed Findings, in the past the requisite
contribution findings have been proposed concurrently with proposing
emission standards for the relevant mobile source category. Thus, prior
contribution findings often focused on a subset of the CAA section
202(a) (or other section) source categories. This final cause or
contribute finding, however, is for all of the CAA section 202(a)
source categories. The Administrator is considering emissions from all
of these source categories in the determination.
Section 202(a) source categories emit the following well-mixed
greenhouse gases: carbon dioxide, methane, nitrous oxide, and
hydrofluorocarbons. As the basis for the Administrator's determination,
EPA analyzed historical data of emissions of the well-mixed greenhouse
gases for motor vehicles and motor vehicle engines in the United States
from 1990 to 2007.
The Proposed Findings discussed a number of possible ways of
assessing cause or contribute and the point was made that no single
approach is required by the statute or has been used exclusively in
previous determinations under the CAA. The Administrator also discussed
how, consistent with prior cause or contribute findings and the
science, she is using emissions as a proxy for contributions to
atmospheric concentrations. This approach is reasonable for the well-
mixed greenhouse gases, because cumulative emissions are responsible
for the cumulative change in the concentrations in the atmosphere.
Similarly, annual emissions are a perfectly reasonable proxy for annual
incremental changes in atmospheric concentrations.
In making a judgment about the contribution of emissions from CAA
section 202(a) source categories, the Administrator focused on making a
reasoned overall comparison of emissions from the CAA section 202(a)
source categories to emissions from other sources of greenhouse gases.
This allows a determination of how the CAA section 202(a) source
categories compare to all of the other sources that together as a group
make up the total emissions contributors to the air pollution problem.
The relative importance of the CAA section 202(a) source categories is
central to making the contribution determination. Both the magnitude of
these emissions and the comparison of these emissions to other sources
provide the basis to determine whether the CAA section 202(a) source
categories may reasonably be judged as contributing to the air
pollution problem.
In many cases EPA makes this kind of comparison of source
categories by a simple percentage calculation that compares the
emissions from the source category at issue to a larger total group of
emissions. Depending on the circumstances, a larger percentage often
means a greater relative impact from that source category compared to
the other sources that make up the total of emissions, and vice versa.
However, the actual numerical percentages may have little meaning when
viewed in isolation. The context of the comparison is needed to ensure
the information is useful in evaluating the relative impact of one
source compared to others. For example, the number of sources involved
and the distribution of emissions across all of the sources can make a
significant difference when evaluating the results of a percentage
calculation. In some cases a certain percentage might mean almost all
other sources are larger or much larger than the source at issue, while
in other circumstances the same percentage could mean that the source
at issue is in fact one of the larger contributors to the total.
The Administrator therefore considered the totality of the
circumstances in order to best understand the role played by CAA
section 202(a) source categories. This is consistent with Congress'
intention for EPA to consider the cumulative impact of all sources of
pollution. In that context, the global nature of the air pollution
problem and the breadth of countries and sources emitting greenhouse
gases means that no single country and no single source category
dominate or are even close to dominating on a global scale. For
example, the United States as a country is the second largest emitter
of greenhouse gases, and emits approximately 18 percent of the world's
total greenhouse gases. The total emissions of greenhouse gases
worldwide are from numerous sources and countries, with each country
and each source category contributing a relatively small percentage of
the total emissions. That means that the relative ranking of countries
or sources is not at all obvious from the magnitude of the percentage
by itself. A country or a source may be a large contributor, in
comparison to other countries or sources, even though its percentage
contribution may appear relatively small.
In this situation, addressing a global air pollution problem may
call for many different sources and countries to address emissions even
if none by itself dominates or comes close to dominating the global
inventory. A somewhat analogous situation can be found in the ozone air
pollution problem in the United States. Emissions of NOx and volatile
organic compounds (VOCs) often come from numerous small sources, as
well as certain large source categories. We have learned that
successful ozone control strategies often need to take this into
account, and address both the larger sources of NOx and VOCs as well as
the many smaller sources, given the breadth of sources that as a group
lead to the total inventory of VOCs and NOx.
The global aspects of the greenhouse gas air pollution problem
amplify this kind of situation many times over, where no single country
or source category dominates or comes close to dominating the global
inventory of greenhouse gas emissions. These unique, global aspects of
the climate change problem tend to support consideration of
contribution at lower percentage levels of emissions than might
otherwise be considered appropriate when addressing a more typical
local or regional air pollution problem. In this situation it is quite
reasonable to consider emissions from source categories that are more
important in relation to other sources, even if their absolute
contribution initially may appear to be small.
In addition, the Administrator is aware of the fact that the United
States is the second largest emitter of well-mixed greenhouse gases in
the world. As the United States evaluates how to address climate
change, the Administrator will analyze the various sources of emissions
and the source's share of U.S. emissions. Thus, when analyzing whether
a source category that emits well-mixed greenhouse gases in the United
States contributes to the global problem, it is appropriate for the
Administrator to consider how that source category fits into the larger
picture of U.S. emissions. This ranking process within the United
States allows the importance of the source category to
[[Page 66539]]
be seen compared to other U.S. sources, informing the judgment of the
importance of emissions from this source category in any overall
national strategy to address greenhouse gas emissions.
It is in this broader context that EPA considered the contribution
of CAA section 202(a) sources. This provides useful information in
determining the importance that should be attached to the emissions
from the CAA section 202(a) sources.
In reaching her determination, the Administrator used two simple
and straightforward comparisons to assess cause or contribute for CAA
section 202(a) source categories: (1) As a share of total current
global aggregate emissions of the well-mixed greenhouse gases; and (2)
as a share of total current U.S. aggregate emissions of the well-mixed
greenhouse gases.
Total well-mixed greenhouse gas emissions from CAA section 202(a)
source categories were compared to total global emissions of the well-
mixed greenhouse gases. The total air pollution problem, as already
discussed, is the elevated and climbing levels of the six greenhouse
gas concentrations in the atmosphere, which are global in nature
because these concentrations are globally well mixed (whether they are
emitted from CAA section 202(a) source categories or any other source
within or outside the United States). In addition, comparisons were
also made to U.S. total well-mixed greenhouse gases emissions to
appreciate how CAA section 202(a) source categories fit into the larger
U.S. contribution to the global problem. It is typical for the
Administrator to consider these kinds of comparisons of emissions of a
pollutant in evaluating contribution to air pollution, such as the
concentrations of that same pollutant in the atmosphere (e.g., the
Administrator analyzes PM2.5 emissions to determine if a
source category contributes to PM2.5 air pollution). When
viewed in the circumstances discussed above, both of these comparisons
provide useful information in determining whether these source
categories should be judged as contributing to the total air pollution
problem.
a. Section 202(a) of the CAA--Share of Global Aggregate Emissions of
the Well-Mixed Greenhouse Gases
Global emissions of well-mixed greenhouse gases have been
increasing, and are projected to continue increasing unless the major
emitters take action to reduce emissions. Total global emissions of
well-mixed greenhouse gases in 2005 (the most recent year for which
data for all countries and all greenhouse gases are available) \39\
were 38,726 teragrams of CO2-equivlant (TgCO2eq.)
\40\ This represents an increase in global greenhouse gas emissions of
about 26 percent since 1990 (excluding land use, land use change and
forestry). In 2005, total U.S. emissions of well-mixed greenhouse gases
were responsible for 18 percent of global emissions, ranking only
behind China, which was responsible for 19 percent of global emissions
of well-mixed greenhouse gases.
---------------------------------------------------------------------------
\39\ The source of global greenhouse gas emissions data, against
which comparisons are made, is the Climate Analysis Indicators Tool
of the World Resources Institute (WRI) (2007). Note that for global
comparisons, all emissions are from the year 2005, the most recent
year for which data for all greenhouse gas emissions and all
countries are available. WRI (2007) Climate Analysis Indicators Tool
(CAIT). Available at http://cait.wri.org. Accessed August 5, 2009.
\40\ One teragram (Tg) = 1 million metric tons. 1 metric ton =
1,000 kg = 1.102 short tons = 2,205 lbs. Long-lived greenhouse gases
are compared and summed together on a CO2 equivalent
basis by multiplying each gas by its Global Warming Potential
(GWPs), as estimated by IPCC. In accordance with UNFCCC reporting
procedures, the U.S. quantifies greenhouse gas emissions using the
100-year time frame values for GWPs established in the IPCC Second
Assessment Report.
---------------------------------------------------------------------------
In 2005 emissions of the well-mixed greenhouse gas pollutant from
CAA section 202(a) source categories represented 4.3 percent of total
global well-mixed greenhouse gas emissions and 28 percent of global
transport well-mixed greenhouse gas emissions (Table 1 of these
Findings). If CAA section 202(a) source categories' emissions of well-
mixed greenhouse gas were ranked against total well-mixed greenhouse
gas emissions for entire countries, CAA section 202(a) source category
emissions would rank behind only China, the United States as a whole,
Russia, and India, and would rank ahead of Japan, Brazil, Germany and
every other country in the world. Indeed, countries with lower
emissions than the CAA section 202(a) source categories are members of
the 17 ``major economies'' ``that meet to advance the exploration of
concrete initiatives and joint ventures that increase the supply of
clean energy while cutting greenhouse gas emissions.'' See http://www.state.gov/g/oes/climate/mem/. It would be anomalous, to say the
least, to consider Japan and these other countries as major players in
the global climate change community and an integral part of the
solution, but not find that CAA section 202(a) source category
emissions contribute to the global problem. Thus, the Administrator
finds that emission of well-mixed greenhouse gases from CAA section
202(a) source categories contribute to the air pollution of well-mixed
greenhouse gases.
Table 1--Comparison to Global Greenhouse Gas (GHG) Emissions (Tg CO2e)
------------------------------------------------------------------------
Sec 202(a) share
2005 (percent)
------------------------------------------------------------------------
All U.S. GHG emissions............ 7,109 23.5
Global transport GHG emissions.... 5,968 28.0
All global GHG emissions.......... 38,726 4.3
------------------------------------------------------------------------
b. Section 202(a) of the CAA--Share of U.S. Aggregate Emissions of the
Well-Mixed Greenhouse Gases
The Administrator considered compared total emissions of the well-
mixed greenhouse gases from CAA section 202(a) source categories to
total U.S. emissions of the well-mixed greenhouse gases as an
indication of the role these sources play in the total U.S.
contribution to the air pollution problem causing climate change.\41\
---------------------------------------------------------------------------
\41\ Greenhouse gas emissions data for the United States in this
section have been updated since the Proposed Findings to reflect
EPA's most up-to-date information, which includes data for the year
2007. The source of the U.S. greenhouse gas emissions data is the
Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2007,
published in 2009 (hereinafter ``U.S. Inventory'').
---------------------------------------------------------------------------
In 2007, U.S. well-mixed greenhouse gas emissions were 7,150
TgCO2eq. The dominant gas emitted was carbon dioxide, mostly
from fossil fuel combustion. Methane was the second largest well-mixed
greenhouse gas, followed by N2O, and the fluorinated gases
(HFCs, PFCs, and SF6). Electricity generation was the
largest emitting sector (2,445 TgCO2eq or 34 percent of
[[Page 66540]]
total U.S. greenhouse gas emissions), followed by transportation (1,995
TgCO2eq or 28 percent) and industry (1,386
TgCO2eq or 19 percent). Emissions from the CAA section
202(a) source categories constitute the major part of the
transportation sector. Land use, land use change, and forestry offset
almost 15 percent of total U.S. emissions through net sequestration.
Total U.S. well-mixed greenhouse gas emissions have increased by over
17 percent between 1990 and 2007. The electricity generation and
transportation sectors have contributed the most to this increase.
In 2007 emissions of well-mixed greenhouse gases from CAA section
202(a) source categories collectively were the second largest emitter
of well-mixed greenhouse gases within the United States (behind the
electricity generating sector), emitting 1,663 TgCO2eq and
representing 23 percent of total U.S. emissions of well-mixed
greenhouse gases (Table 2 of these Findings). The Administrator is
keenly aware that the United States is the second largest emitter of
well-mixed greenhouse gases. Part of analyzing whether a sector within
the United States contributes to the global problem is to see how those
emissions fit into the contribution from the United States as a whole.
This informs her judgment as to the importance of emissions from this
source category in any overall national strategy to address greenhouse
gas emissions. Thus, it is relevant that CAA section 202(a) source
categories are the second largest emitter of well-mixed greenhouse
gases in the country. This is part of the Administrator looking at the
totality of the circumstances. Based on this the Administrator finds
that emission of well-mixed greenhouse gases from CAA section 202(a)
source categories contribute to the air pollution of well-mixed
greenhouse gases.
Table 2--Sectoral Comparison to Total U.S. Greenhouse Gas (GHG) Emissions (Tg CO2e)
----------------------------------------------------------------------------------------------------------------
U.S. emissions 1990 1995 2000 2005 2006 2007
----------------------------------------------------------------------------------------------------------------
Section 202(a) GHG emissions...... 1231.9 1364.4 1568.1 1670.5 1665.7 1663.1
Share of U.S. (%)................. 20.2% 21.1% 22.4% 23.5% 23.6% 23.3%
Electricity Sector emissions...... 1859.1 1989.0 2329.3 2429.4 2375.5 2445.1
Share of U.S. (%)................. 30.5% 30.8% 33.2% 34.2% 33.7% 34.2%
Industrial Sector emissions....... 1496.0 1524.5 1467.5 1364.9 1388.4 1386.3
Share of U.S. (%)................. 24.5% 23.6% 20.9% 19.2% 19.7% 19.4%
-----------------------------------------------------------------------------
Total U.S. GHG emissions...... 6098.7 6463.3 7008.2 7108.6 7051.1 7150.1
----------------------------------------------------------------------------------------------------------------
C. Response to Key Comments on the Administrator's Cause or Contribute
Finding
EPA received numerous public comments regarding the Administrator's
proposed cause or contribute finding. Below is a brief discussion of
some of the key comments. Responses to comments on this issue are also
contained in the Response to Comments document, Volume 10.
1. The Administrator Reasonably Defined the ``Air Pollutant'' for the
Cause or Contribute Analysis
a. The Supreme Court Held that Greenhouse Gases Fit Within the
Definition of ``Air Pollutant'' in the CAA
Several commenters reiterate arguments already rejected by the
Supreme Court, arguing that greenhouse gases do not fit into the
definition of ``air pollutant'' under the CAA. In particular, at least
one commenter contends that EPA must show how greenhouse gases impact
or materially change ``ambient air'' when defining air pollutant and
making the endangerment finding. This commenter argues that because
carbon dioxide is a naturally occurring and necessary element in the
atmosphere, it cannot be considered to materially change air.
These and similar arguments were already rejected by the Supreme
Court in Massachusetts v. EPA, 549 U.S. 497 (2007). Briefs before the
Supreme Court also argued that carbon dioxide is an essential role for
life on earth and therefore cannot be considered an air pollutant, and
that the concentrations of greenhouse gases that are a potential
problem are not in the ``ambient air'' that people breathe.
The Court rejected all of these and other arguments, noting that
the statutory text forecloses these arguments. ``The Clean Air Act's
sweeping definition of `air pollutant' includes `any air pollution
agent or combination of such agents, including any physical, chemical *
* * substance or matter which is emitted into or otherwise enters the
ambient air . * * *' Sec. 7602(g) (emphasis added). On its face, the
definition embraces all airborne compounds of whatever stripe, and
underscores that intent through the repeated use of the word `any.'
Carbon dioxide, methane, nitrous oxide, and hydrofluorocarbons are
without a doubt `physical [and] chemical * * * substance[s] which [are]
emitted into * * * the ambient air.' The statute is unambiguous.''
547 U.S. at 529-30 (footnotes omitted); see also id. at 530, n26
(the distinction regarding ambient air, however, finds no support in
the text of the statute, which uses the phrase ``the ambient air''
without distinguishing between atmospheric layer.). Thus, the question
of whether greenhouse gases fit within the definition of air pollutant
under the CAA has been decided by the Supreme Court and is not being
revisited here.
b. The Definition of Air Pollutant May Include Substances Not Emitted
by CAA Section 202(a) Sources
Many commenters argue that the definition of ``air pollutant''--
here well-mixed greenhouse gases--cannot include PFCs and SF6 because
they are not emitted by CAA section 202(a) motor vehicles and hence,
cannot be part of any ``air pollutant'' emitted by such sources. They
argue that by improperly defining ``air pollutant'' to include
substances that are not present in motor vehicle emissions, the Agency
has exceeded its statutory authority under CAA section 202(a).
Commenters contend that past endangerment findings under CAA section
202(a) demonstrate EPA's consistent approach of defining ``air
pollutant(s)'' in accordance with the CAA's clear direction, to include
only those pollutants emitted from the relevant source category (citing
Notice of Proposed Rulemaking for Heavy-Duty Engine and Vehicle
Standards finding that ``emissions of NOX, VOCs,
SOX, and PM from heavy-duty trucks can reasonably be
anticipated to endanger the public health or welfare.'' (65 FR 35436,
June 2, 2000). Commenters argue that EPA itself is inconsistent in the
Proposed Findings, sometimes referring
[[Page 66541]]
to ``air pollutant'' as the group of six greenhouse gases, and other
times falling back on the four greenhouse gases emitted by motor
vehicles.
EPA acknowledges that the Proposed Findings could have been clearer
regarding the proposed definition of air pollutant, and how it was
being applied to CAA section 202(a) sources, which emit only four of
the six substances that meet the definition of well-mixed greenhouse
gases. However, our interpretation does not exceed EPA's authority
under CAA section 202(a). It is reasonable to define the air pollutant
under CAA section 202(a) to include substances that have similar
attributes (as discussed above), even if not all of the substances that
meet that definition are emitted by motor vehicles. For example, as
commenters note, EPA has heavy duty truck standards applicable to VOCs
and PM, but it is highly unlikely that heavy duty trucks emit every
substance that is included in the group defined as VOC or PM. See 40
CFR 51.100(s) (defining volatile organic compound (VOC) as ``any
compound of carbon, excluding carbon monoxide, carbon dioxide, carbonic
acid, metallic carbides or carbonates, and ammonium carbonate, which
participates in atmospheric photochemical reactions'', a list of
exemptions are also included in the definition); 40 CFR 51.100(oo)
(defining particulate matter (PM) as ``any airborne finely divided
solid or liquid material with an aerodynamic diameter smaller than 100
micrometers'').
In this circumstance the number of substances included in the
definition of well-mixed greenhouse gases is much smaller than other
``group'' air pollutants (e.g., six greenhouse gases versus hundreds of
VOCs), and CAA section 202(a) sources emit an easily discernible number
of these six substances. However, this does not mean that the
definition of the well-mixed greenhouse gases as the air pollutant is
unreasonable. By defining well-mixed greenhouse gases as a single air
pollutant comprised of six substances with common attributes, the
Administrator is giving effect to these shared attributes and how they
are relevant to the air pollution to which they contribute. The fact
that these six substances share these common, relevant attributes is
true regardless of the source category being evaluated for
contribution. Grouping these six substances as one air pollutant is
reasonable regardless of whether a contribution analysis is undertaken
for CAA section 202(a) sources that emit one subset of the six
substances (e.g., carbon dioxide, CH4, N20 and
HFCs, but not PFCs and SF6), or for another category of
sources that may emit another subset. For example, electronics
manufacturers that may emit N2O, PFCs, HFCs, SF6
and other fluorinated compounds, but not carbon dioxide or
CH4 unless there is on-site fuel combustion. In other words,
it is not necessarily the source category being evaluated for
contribution that determines the reasonableness of defining a group air
pollutant based on the shared attributes of the group.
Even if EPA agreed with commenters, and defined the air pollutant
as the group of four compounds emitted by CAA section 202(a) sources,
it would not change the result. The Administrator would make the same
contribution finding as it would have no material effect on the
emissions comparisons discussed above.
c. It Was Reasonable for the Administrator To Define the Single Air
Pollutant as the Group of Substances With Common Attributes
Several commenters disagree with EPA's proposed definition of a
single air pollutant composed of the six well-mixed greenhouse gases as
a class. Commenters argue that the analogy to VOCs is misplaced because
VOCs are all part of a defined group of chemicals, for which there are
established quantification procedures, and for which there were
extensive data showing that the group of compounds had demonstrated and
quantifiable effects on ambient air and human health and welfare, and
for which verifiable dispersion models existed. They contend this is in
stark contrast to the entirely diverse set of organic and inorganic
compounds EPA has lumped together for purposes of the Proposed
Findings, and for which no model can accurately predict or quantify the
actual impact or improvement resulting from controlling the compounds.
Moreover, they argue that the gases EPA is proposing to list together
as one pollutant are all generated by different processes and, if
regulated, would require different types of controls; the four gases
emitted by mobile sources can generally be limited only by using
controls that are specific to each.
At least one commenter argues that EPA cannot combine greenhouse
gases into one pollutant because their common attribute is not a
``physical, chemical, biological or radioactive property'' (quoting
from CAA section 302(g)), but rather their effect or impacts on the
environment. They say this differs from VOCs, which share the common
attribute of volatility, or PM which shares the physical property of
being particles.
As discussed above, the well-mixed greenhouse gases share physical
attributes, as well as attributes based on sound policy considerations.
The definition of ``air pollutant'' in CAA section 302(g) does not
limit consideration of common attributes to those that are ``physical,
chemical, biological or radioactive property'' as one commenter claims.
Rather, the definition's use of the adjectives ``physical, chemical,
biological or radioactive'' refer to the different types of substance
or matter that is emitted. It is not a limitation on what
characteristics the Administrator may consider when deciding how to
group similar substances when defining a single air pollutant.
The common attributes that the Administrator considered when
defining the well-mixed greenhouse gases are reasonable. While these
six substances may originate from different processes, and require
different control strategies, that does not detract from the fact that
they are all long-lived, well-mixed in the atmosphere, directly
emitted, of well-known radiative forcing, and generally grouped and
considered together in climate change scientific and policy forums.
Indeed, other group pollutants also originate from a variety of
processes and a result may require different control technologies. For
example, both a power plant and a dirt road can result in PM emissions,
and the method to control such emissions at each source would be
different. But these differences in origin or control do not undermine
the reasonableness of considering PM as a single air pollutant. The
fact that there are differences, as well as similarities, among the
well-mixed greenhouse gases does not render the decision to group them
together as one air pollutant unreasonable.
2. The Administrator's Cause or Contribute Analysis Was Reasonable
a. The Administrator Does Not Need To Find Significant Contribution, or
Establish a Bright Line
Many commenters essentially argue that EPA must establish a bright
line below which it would never find contribution regardless of the air
pollutant, air pollution, and other factors before the Agency. For
example, some commenters argue that EPA must provide some basis for
determining de minimis amounts that fall below the threshold of
``contributing'' to the endangerment of public health and welfare under
CAA section 202(a).
[[Page 66542]]
Commenters take issue with EPA's statement that it ``need not determine
at this time the circumstances in which emissions would be trivial or
de minimis and would not warrant a finding of contribution.''
Commenters argue that EPA cannot act arbitrarily by determining that a
constituent contributing a certain percent to endangerment in one
instance is de minimis and in another is contributing to endangerment
of public health and welfare. They request that EPA revise the preamble
language to make clear that the regulated community can rely on its
past determinations with respect to ``contribution'' determinations to
predict future agency action and argue that EPA should promulgate
guidance on how it determines whether a contribution exceeds a de
minimis level for purposes of CAA section 202(a) before finalizing the
proposal.
The commenters that argue that the air pollution EPA must analyze
to determine endangerment is limited to the air pollution resulting
from new motor vehicles also argue that as a result, the contribution
of emissions from new motor vehicles must be significant. They
essentially contend that the endangerment and cause or contribute tests
are inter-related and the universe of both tests is the same. In
support of their argument, commenters argue that because the clause
``cause, or contribute to, air pollution'' is in plural form, it must
be referring back to ``any class or classes of new motor vehicles or
new motor vehicle engines,'' demonstrating that EPA must consider only
the emissions from new motor vehicles which emit the air pollution
which endangers.
Since the Administrator issued the Proposed Findings, the DC
Circuit issued another opinion discussing the concept of contribution.
See Catawba County v. EPA, 571 F.3d 20 (DC Cir. 2009). This decision,
along with others, supports the Administrator's interpretation that the
level of contribution under CAA section 202(a) does not need to be
significant. The Administrator is not required to establish a bright
line below which she would never find contribution under any
circumstances. Finally, it is reasonable for the Administrator to apply
a ``totality-of-the-circumstances test to implement a statute that
confers broad discretionary authority, even if the test lacks a
definite `threshold' or `clear line of demarcation to define an open-
ended term.'' Id. at 39 (citations omitted).
In upholding EPA's PM2.5 attainment and nonattainment
designation decisions, the DC Circuit analyzed CAA section 107(d),
which requires EPA to designate an area as nonattainment if it
``contributes to ambient air quality in a nearby area'' not attaining
the national ambient air quality standards. Id. at 35. The court noted
that it had previously held that the term ``contributes'' is ambiguous
in the context of CAA language. See EDF v. EPA, 82 F.3d 451, 459 (DC
Cir. 1996). ``[A]mbiguities in statutes within an agency's jurisdiction
to administer are delegations of authority to the agency to fill the
statutory gap in reasonable fashion.'' 571 F.3d at 35 (citing Nat's
Cable & Telecomms. Ass'c v. Brand X Internet Servs, 545 U.S. 967, 980
(2005)).
The court then proceeded to consider and reject petitioners'
argument that the verb ``contributes'' in CAA section 107(d)
necessarily connotes a significant causal relationship. Specifically,
the DC Circuit again noted that the term is ambiguous, leaving it to
EPA to interpret in a reasonable manner. In the context of this
discussion, the court noted that ``a contribution may simply exacerbate
a problem rather than cause it * * * '' 571 F.3d at 39. This is
consistent with the DC Circuit's decision in Bluewater Network v. EPA,
370 F.3d 1 (DC Cir. 2004), in which the court noted that the term
contribute in CAA section 213(a)(3) ``[s]tanding alone, * * * has no
inherent connotation as to the magnitude or importance of the relevant
`share' in the effect; certainly it does not incorporate any
`significance' requirement.'' 370 F.3d at 13. The court found that the
bare ``contribute'' language invests the Administrator with discretion
to exercise judgment regarding what constitutes a sufficient
contribution for the purpose of making an endangerment finding. Id. at
14.
Finally, in Catawba County, the DC Circuit also rejected
``petitioners' argument that EPA violated the statute by failing to
articulate a quantified amount of contribution that would trigger'' the
regulatory action. 571 F.3d at 39. Although petitioners preferred that
EPA establish a bright-line test, the court recognized that the statute
did not require that EPA ``quantify a uniform amount of contribution.''
Id.
Given this context, it is entirely reasonable for the Administrator
to interpret CAA section 202(a) to require some level of contribution
that, while more than de minimis or trivial, does not rise to the level
of significance. Moreover, the approach suggested by at least one
commenter collapses the two prongs of the test by requiring that
contribution must be significant because any climate change impacts
upon which an endangerment determination is made result solely from the
greenhouse gas emissions of motor vehicles. It essentially eliminates
the ``contribute'' part of the ``cause or contribute'' portion of the
test. This approach was clearly rejected by the en banc court in Ethyl.
541 F.2d at 29 (rejecting the argument that the emissions of the fuel
additive to be regulated must ``in and of itself, i.e. considered in
isolation, endanger[ ] public health.''); see also Catawba County, 571
F.3d at 39 (noting that even if the test required significant
contribution it would be reasonable for EPA to find a county's addition
of PM2.5 is significant even though the problem would
persist in its absence). It is the commenter, not EPA that is ignoring
the statutory language. Whether or not the clause ``cause, or
contribute to, air pollution'' refers back to ``any class or classes of
new motor vehicles or new motor vehicle engines,'' or to ``emission of
any air pollutant,'' the language of CAA section 202(a) clearly
contemplates that emission of an air pollutant from any class or
classes may merely contribute to, versus cause, the air pollution which
endangers.
It is also reasonable for EPA to decline to establish a ``bright-
line `objective' test of contribution.'' 571 F.3d at 39. As noted in
the Proposed Findings, when exercising her judgment, the Administrator
not only considers the cumulative impact, but also looks at the
totality of the circumstances (e.g., the air pollutant, the air
pollution, the nature of the endangerment, the type of source category,
the number of sources in the source category, and the number and type
of other source categories that may emit the air pollutant) when
determining whether the emissions justify regulation under the CAA. Id.
(It is reasonable for an agency to adopt a totality-of-the-
circumstances test).
Even if EPA agreed that a level of significance was required to
find contribution, for the reasons discussed above, EPA would find that
the contribution from CAA section 202(a) source categories is
significant. Their emissions are larger than the great majority of
emitting countries, larger than several major emitting countries, and
they constitute one of the largest parts of the U.S. emissions
inventory.
b. The Unique Global Aspects of Climate Change Are an Appropriate
Consideration in the Contribution Analysis
Some commenters disagree with statements in the Proposed Findings
that the ``unique, global aspects of the climate change problem tend to
support a finding that lower levels of emissions should be considered
to contribute to the air pollution than might otherwise
[[Page 66543]]
be appropriate when considering contribution to a local or regional air
pollution problem.'' They argue there is no basis in the CAA or
existing EPA policy for this position, and that it reveals an apparent
effort to expand EPA's authority to the ``truly trivial or de minimis''
sources that are acknowledged to be outside the scope of regulation, in
that it expands EPA's authority to regulate pollutants to address
global effects.
Commenters also assert that contrary to EPA's position, lower
contribution numbers are appropriate when looking at local pollution,
like nonattainment concerns--in other words, in the context of a
statutory provision like CAA section 213 specifically aimed at
targeting small source categories to help nonattainment areas meet air
quality standards. However, they conclude this policy is simply
inapplicable in the context of global climate change.
As discussed above, the term ``contribute'' is ambiguous and
subject to the Administrator's reasonable interpretation. It is
entirely appropriate for the Administrator to look at the totality of
the circumstances when making a finding of contribution. In this case,
the Administrator believes that the global nature of the problem
justifies looking at contribution in a way that takes account of these
circumstances. More specifically, because climate change is a global
problem that results from global greenhouse gas emissions, there are
more sources emitting greenhouse gases (in terms both of absolute
numbers of sources and types of sources) than EPA typically encounters
when analyzing contribution towards a more localized air pollution
problem. From a percentage perspective, there are no dominating sources
and fewer sources that would even be considered to be close to
dominating. The global problem is much more the result of numerous and
varied sources each of which emit what might seem to be smaller
percentage amounts when compared to the total. The Administrator's
approach recognizes this reality, and focuses on evaluating the
relative importance of the CAA section 202(a) source categories
compared to other sources when viewed in this context.
This recognition of the unique totality of the circumstances before
the Administrator now as compared to previous contribution decisions is
entirely appropriate. It is not an attempt by the Administrator to
regulate ``truly trivial or de minimis'' sources, or to regulate
sources based on their global effects. The Administrator is determining
whether greenhouse gas emissions from CAA section 202(a) sources
contribute to an air pollution problem is endangering U.S. public
health and welfare. As discussed in the Proposed Findings, no single
greenhouse gas source category dominates on the global scale, and many
(if not all) individual greenhouse gas source categories could appear
small in comparison to the total, when, in fact, they could be very
important contributors in terms of both absolute emissions or in
comparison to other source categories, globally or within the United
States. If the United States and the rest of the world are to combat
the risks associated with global climate change, contributors must do
their part even if their contributions to the global problem, measured
in terms of percentage, are smaller than typically encountered when
tackling solely regional or local environmental issues. The commenters'
approach, if used globally, would effectively lead to a tragedy of the
commons, whereby no country or source category would be accountable for
contributing to the global problem of climate change, and nobody would
take action as the problem persists and worsens. The Administrator's
approach, on the contrary, avoids this kind of approach, and is a
reasonable exercise of her discretion to determine contribution in the
global context in which this issue arises.
Importantly, as discussed above, the contribution from CAA section
202(a) sources is anything but trivial or de minimis under any
interpretation of contribution. See, Massachusetts v. EPA, 549 U.S. at
1457-58 (``Judged by any standard, U.S. motor-vehicle emissions make a
meaningful contribution to greenhouse gas concentrations and hence, * *
* to global warming'').
c. The Administrator Reasonably Relied on Comparisons of Emissions From
Existing CAA Section 202(a) Source Categories
i. It Was Reasonable To Use Existing Emissions From Existing CAA
Section 202(a) Source Categories Instead of Projecting Future Emissions
From New CAA Section 202(a) Source Categories
Many commenters argue that EPA improperly evaluated the emissions
from the entire motor vehicle fleet, and it is required to limit its
calculation to just emissions from new motor vehicles. Thus the
emissions that EPA should consider in the cause or contribute
determination is far less than the 4.3 percent of U.S. greenhouse gas
emissions attributed to motor vehicles in the Proposed Findings,
because this number includes both new and existing motor vehicles. One
commenter calculated the emissions from new motor vehicles as being 1.8
percent of global emissions, assuming approximately one year of new
motor vehicle production in the United States (11 million vehicles) in
a total global count currently of approximately 600 million motor
vehicles.
In the Proposed Findings, EPA determined the emissions from the
entire fleet of motor vehicles in the United States for a certain
calendar year. EPA explained that, consistent with its traditional
practice, it used the recent motor vehicle emissions inventory for the
entire fleet as a surrogate for estimates of emissions for just new
motor vehicles and engines. This was appropriate because future
projected emissions are uncertain and current emissions data are a
reasonable proxy for near-term emissions.
In effect, EPA is using the inventory for the current fleet of
motor vehicles as a reasonable surrogate for a projection of the
inventory from new motor vehicles over the upcoming years. New motor
vehicles are produced year in and year out, and over time the fleet
changes over to a fleet composed of such vehicles. This occurs in a
relatively short time frame, compared to the time period at issue for
endangerment. Because new motor vehicles are produced each year, and
continue to emit over their entire life, over a relatively short period
of time the emission from the entire fleet is from vehicles produced
after a certain date. In addition, the emissions from new motor
vehicles are not limited to the emissions that occur only during the
one year when they are new, but are emissions over the entire life of
the vehicle.
In such cases, EPA has traditionally used the recent emissions from
the entire current fleet of motor vehicles as a reasonable surrogate
for such a projection instead of trying to project and model those
emissions. While this introduces some limited degree of uncertainty,
the difference between recent actual emissions from the fleet and
projected future emissions from the fleet is not expected to differ in
any way that would substantively change the decision made concerning
cause or contribution. There is not a specific numerical bright line
that must be achieved, and the numerical percentages are not treated
and do not need to be treated as precise values. This approach provides
a reasonable and clear indication of the relative magnitudes involved,
and EPA does not believe that attempting to make future
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projections (for both vehicles and the emissions value they are
compared to) would provide any greater degree of accuracy or precision
in developing such a relative comparison.
ii. The Administrator Did Not Have To Use a Subset or Reduced Emissions
Estimate From Existing CAA Section 202(a) Source Categories
Several commenters note that although EPA looks at emissions from
all motor vehicles regulated under CAA section 202(a) in its
contribution analysis, the Presidential announcement in May 2009
indicated that EPA was planning to regulate only a subset of 202(a)
sources. Thus, they question whether the correct contribution analysis
should look only at the emissions from that subset and not all CAA
section 202(a) sources. Some commenters also argue that because
emission standards will not eliminate all greenhouse gas emissions from
motor vehicles, the comparison should compare the amount of greenhouse
gas emissions ``reduced'' by those standards to the global greenhouse
emissions. They also contend that the cost of the new standards will
cause individual consumers, businesses, and other vehicle purchasers to
hold on to their existing vehicles to a greater extent, thereby
decreasing the amount of emissions reductions attributable to the
standard and appropriately considered in the contribution analysis.
Some commenters go further and contend that EPA also can only include
that incremental reduction that the EPA regulations will achieve beyond
any reductions resulting from CAFE standards that NHTSA will set.
Although the May announcement and September proposed rule involved
only the light duty motor vehicle sector, the Administrator is making
this finding for all classes of new motor vehicles under CAA section
202(a). Thus, although the announcement and proposed rule involve light
duty vehicles, EPA is working to develop standards for the rest of the
classes of new motor vehicles under CAA section 202(a). As the Supreme
Court noted, EPA has ``significant latitude as to the manner, timing,
content, and coordination of its regulations with those of other
agencies. Massachusetts v. EPA, 549 U.S. at 533.
The argument that the Administrator can only look at that portion
of emissions that will be reduced by any CAA section 202(a) standards,
and even then only the reduction beyond those attributable to CAFE
rules, finds no basis in the statutory language. The language in CAA
section 202(a) requires that the Administrator set ``standards
applicable to the emission of any air pollutant from [new motor
vehicles], which in [her] judgment cause, or contribute to, air
pollution which [endangers].'' It does not say set ``standards
applicable to the emission of any air pollutant from [new motor
vehicles], if in [her] judgment the emissions of that air pollutant as
reduced by that standard cause, or contribute to, air pollution which
[endangers].'' As discussed above, the decisions on cause or contribute
and endangerment are separate and distinct from the decisions on what
emissions standards to set under CAA section 202(a). The commenter's
approach would improperly integrate these separate decisions. Indeed,
because, as discussed above, the Administrator does not have to propose
standards concurrent with the endangerment and cause or contribute
findings, she would have to be prescient to know at the time of the
contribution finding exactly the amount of the reduction that would be
achieved by the standards to be set. As discussed above, for purposes
of these findings we look at what would be the emissions from new motor
vehicles if no action were taken. Current emissions from the existing
CAA section 202(a) vehicle fleet are an appropriate estimate.
d. The Administrator Reasonably Compared CAA Section 202(a) Source
Emissions to Both Global and Domestic Emissions of Well-Mixed
Greenhouse Gases
EPA received many comments on the appropriate comparison(s) for the
contribution analysis. Several commenters argue that in order to get
around the ``problem'' of basing an endangerment finding upon a source
category that contributes only 1.8 percent annually to global
greenhouse gas emissions, EPA inappropriately also made comparisons to
total U.S. greenhouse gas emissions. These commenters argue that a
comparison of CAA section 202(a) source emissions to U.S. greenhouse
gas emissions, versus global emissions, is arbitrary for purposes of
the cause or contribute analysis, because it conflicts with the
Administrator's definition of ``air pollution,'' as well as the nature
of global warming. They note that throughout the Proposed Findings, the
Administrator focuses on the global nature of greenhouse gas. Thus,
they continue, while the percentage share of motor vehicle emissions at
the U.S. level may be relevant for some purposes, it is irrelevant to a
finding of whether these emissions contribute to the air pollution,
which the Administrator has proposed to define on a global rather than
a domestic basis. Commenters also accuse EPA of arbitrarily picking and
choosing when it takes a global approach (e.g., endangerment finding)
and when it does not (e.g., contribution findings).
The language of CAA section 202(a) is silent regarding how the
Administrator is to make her contribution analysis. While it requires
that the Administrator assess whether emission of an air pollutant
contributes to air pollution which endangers, it does not limit how she
may undertake that assessment. It surely is reasonable that the
Administrator look at how CAA section 202(a) source category emissions
compare to global emissions on an absolute basis, by themselves. But
the United States as a nation is the second largest emitter of
greenhouse gases. It is entirely appropriate for the Administrator to
decide that part of understanding how a U.S. source category emitting
greenhouse gases fits into the bigger picture of global climate change
is to appreciate how that source category fits into the contribution
from the United States as a whole, where the United States as a country
is a major emitter of greenhouse gases. Knowing that CAA section 202(a)
source categories are the second largest emitter of well-mixed
greenhouse gases in the country is relevant to understanding what role
they play in the global problem and hence whether they ``contribute''
to the global problem. Moreover, the Administrator is not ``picking and
choosing'' when she applies a global or domestic approach in these
Findings. Rather, she is looking at both of these emissions comparisons
as appropriate under the applicable science, facts, and law.
e. The Amount of Well-Mixed Greenhouse Gas Emissions From CAA Section
202(a) Sources Reasonably Supports a Finding of Contribution
Many commenters argue that the ``cause or contribute'' prong of the
Proposal's endangerment analysis fails to satisfy the applicable legal
standard, which requires more than a minimal contribution to the ``air
pollution reasonably anticipated to endanger public health or
welfare.'' They contend that emissions representing approximately four
percent of total global greenhouse gas emissions are a minimal
contribution to global greenhouse gas concentrations.
EPA disagrees. As stated above, CAA section 202(a) source category
total emissions of well-mixed greenhouse gases are higher than most
countries in the world; countries that the U.S. and others believe play
a major role in the
[[Page 66545]]
global climate change problem. Moreover, the percent of global well-
mixed greenhouse gas emissions that CAA section 202(a) source
categories represent is higher than percentages that the EPA has found
contribute to air pollution problems. See Bluewater Network, 370 F.3d
at 15 (``For Fairbanks, this contribution was equivalent to 1.2 percent
of the total daily CO inventory for 2001.'') As noted above, there is
no bright line for assessing contribution, but as discussed in the
Proposed Findings and above, when looking at a global problem like
climate change, with many sources of emissions and no dominating
sources from a global perspective, it is reasonable to consider that
lower percentages contribute than one may consider when looking at a
local or regional problem involving fewer sources of emissions. The
Administrator agrees that ``[j]udged by any standard, U.S. motor-
vehicle emissions make a meaningful contribution to greenhouse gas
concentrations and hence, * * * to global warming.'' Massachusetts v.
EPA, 549 U.S. at 525.
VI. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory Planning and Review
Under Executive Order (EO) 12866 (58 FR 51735, October 4, 1993),
this action is a ``significant regulatory action'' because it raises
novel policy issues. Accordingly, EPA submitted this action to the
Office of Management and Budget (OMB) for review under EO 12866 and any
changes made in response to Office of Management and Budget (OMB)
recommendations have been documented in the docket for this action.
B. Paperwork Reduction Act
This action does not impose an information collection burden under
the provisions of the Paperwork Reduction Act, 44 U.S.C. 3501 et seq.
Burden is defined at 5 CFR 1320.3(b). These Findings do not impose an
information collection request on any person.
C. Regulatory Flexibility Act
The Regulatory Flexibility Act (RFA) generally requires an agency
to prepare a regulatory flexibility analysis of any rule subject to
notice and comment rulemaking requirements under the Administrative
Procedure Act or any other statute unless the agency certifies that the
rule will not have a significant economic impact on a substantial
number of small entities. Small entities include small businesses,
small organizations, and small governmental jurisdictions.
For purposes of assessing the impacts of this action on small
entities, small entity is defined as: (1) A small business as defined
by the Small Business Administration's (SBA) regulations at 13 CFR
121.201; (2) a small governmental jurisdiction that is a government of
a city, county, town, school district, or special district with a
population of less than 50,000; and (3) a small organization that is
any not-for-profit enterprise which is independently owned and operated
and is not dominant in its field.
Because these Findings do not impose any requirements, the
Administrator certifies that this action will not have a significant
economic impact on a substantial number of small entities. This action
does not impose any requirements on small entities. The endangerment
and cause or contribute findings do not in-and-of-themselves impose any
new requirements but rather set forth the Administrator's determination
on whether greenhouse gases in the atmosphere may reasonably be
anticipated to endanger public health or welfare, and whether emissions
of greenhouse gases from new motor vehicles and engines contribute to
this air pollution. Accordingly, the action affords no opportunity for
EPA to fashion for small entities less burdensome compliance or
reporting requirements or timetables or exemptions from all or part of
the Findings.
D. Unfunded Mandates Reform Act
This action contains no Federal mandates under the provisions of
Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), 2 U.S.C.
1531-1538 for State, local, or tribal governments or the private
sector. The action imposes no enforceable duty on any State, local or
tribal governments or the private sector. Therefore, this action is not
subject to the requirements of sections 202 or 205 of the UMRA.
This action is also not subject to the requirements of section 203
of UMRA because it contains no regulatory requirements that might
significantly or uniquely affect small governments. This finding does
not impose any requirements on industry or other entities.
E. Executive Order 13132: Federalism
This action does not have federalism implications. Because this
action does not impose requirements on any entities, it will not have
substantial direct effects on the States, on the relationship between
the national government and the States, or on the distribution of power
and responsibilities among the various levels of government, as
specified in Executive Order 13132. Thus, Executive Order 13132 does
not apply to this action.
F. Executive Order 13175: Consultation and Coordination With Indian
Tribal Governments
This action does not have tribal implications, as specified in
Executive Order 13175 (65 FR 67249, November 9, 2000). This action does
not have substantial direct effects on one or more Indian tribes, on
the relationship between the Federal Government and Indian tribes, or
on the distribution of power and responsibilities between the Federal
Government and Indian tribes, nor does it impose any enforceable duties
on any Indian tribes. Thus, Executive Order 13175 does not apply to
this action.
G. Executive Order 13045: Protection of Children From Environmental
Health Risks and Safety Risks
EPA interprets EO 13045 (62 FR 19885, April 23, 1997) as applying
only to those regulatory actions that concern health or safety risks,
such that the analysis required under section 5-501 of the EO has the
potential to influence the regulation. This action is not subject to EO
13045 because it does not establish an environmental standard intended
to mitigate health or safety risks. Although the Administrator
considered health and safety risks as part of these Findings, the
Findings themselves do not impose a standard intended to mitigate those
risks.
H. Executive Order 13211: Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use
This action is not a ``significant energy action'' as defined in
Executive Order 13211 (66 FR 28355 (May 22, 2001)), because it is not
likely to have a significant adverse effect on the supply,
distribution, or use of energy because it does not impose any
requirements.
I. National Technology Transfer and Advancement Act
Section 12(d) of the National Technology Transfer and Advancement
Act of 1995 (``NTTAA''), Public Law 104-113, 12(d) (15 U.S.C. at 272
note) directs EPA to use voluntary consensus standards in its
regulatory activities unless to do so would be inconsistent with
applicable law or otherwise impractical. Voluntary consensus
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standards are technical standards (e.g., materials specifications, test
methods, sampling procedures, and business practices) that are
developed or adopted by voluntary consensus standards bodies. NTTAA
directs EPA to provide Congress, through OMB, explanations when the
Agency decides not to use available and applicable voluntary consensus
standards.
This action does not involve technical standards. Therefore, EPA
did not consider the use of any voluntary consensus standards.
J. Executive Order 12898: Federal Actions To Address Environmental
Justice in Minority Populations and Low-Income Populations
Executive Order (EO) 12898 (59 FR 7629, Feb. 16, 1994) establishes
federal executive policy on environmental justice. Its main provision
directs federal agencies, to the greatest extent practicable and
permitted by law, to make environmental justice part of their mission
by identifying and addressing, as appropriate, disproportionately high
and adverse human health or environmental effects of their programs,
policies, and activities on minority populations and low-income
populations in the United States.
EPA has determined that these Findings will not have
disproportionately high and adverse human health or environmental
effects on minority or low-income populations because it does not
affect the level of protection provided to human health or the
environment. Although the Administrator considered climate change risks
to minority or low-income populations as part of these Findings, this
action does not impose a standard intended to mitigate those risks and
does not impose requirements on any entities.
K. Congressional Review Act
The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the
Small Business Regulatory Enforcement Fairness Act of 1996, generally
provides that before a rule may take effect, the agency promulgating
the rule must submit a rule report, which includes a copy of the rule,
to each House of the Congress and to the Comptroller General of the
United States. EPA will submit a report containing this rule and other
required information to the U.S. Senate, the U.S. House of
Representatives, and the Comptroller General of the United States. This
action is not a ``major rule'' as defined by 5 U.S.C. 804(2). This rule
will be effective January 14, 2010.
Dated: December 7, 2009.
Lisa P. Jackson,
Administrator.
[FR Doc. E9-29537 Filed 12-14-09; 8:45 am]
BILLING CODE 6560-50-P