No. 05-1120
In the Supreme Court of the United States
__________
COMMONWEALTH OF MASSACHUSETTS, et al.,
Petitioners,
v.
U.S. ENVIRONMENTAL PROTECTION AGENCY, et al.,
Respondents.
__________
On Writ of Certiorari to the
United States Court of Appeals
for the District of Columbia Circuit
__________
BRIEF OF AMICI CURIAE CLIMATE SCIENTISTS
DAVID BATTISTI, WILLIAM E. EASTERLING,
CHRISTOPHER FIELD, INEZ FUNG, JAMES E.
HANSEN, JOHN HARTE, EUGENIA KALNAY, DANIEL
KIRK-DAVIDOFF, PAMELA A. MATSON, JAMES C.
MCWILLIAMS, MARIO J. MOLINA, JONATHAN T.
OVERPECK, F. SHERWOOD ROWLAND, JOELLEN
RUSSELL, SCOTT R. SALESKA, EDWARD SARACHIK,
JOHN M. WALLACE, AND STEVEN C. WOFSY
IN SUPPORT OF PETITIONERS
__________
JOHN C. DERNBACH ROBERT B.MCKINSTRY, JR.*
WIDENER UNIVERSITY PENN STATE UNIVERSITY
LAW SCHOOL 432 FOREST RESOURCES
3800 VARTAN WAY BUILDING
HARRISBURG, PA 17106 UNIVERSITY PARK, PA 16802
(717) 541-1933 (484) 467-3207
* Counsel of Record
KIRSTEN H. ENGEL STEPHANIE TAI
UNIVERSITY OF ARIZONA UNIVERSITY OF WISCONSIN
COLLEGE OF LAW LAW SCHOOL
1201 E. SPEEDWAY BLVD. 957 BASCOM MALL
TUCSON, AZ 85721 MADISON, WI 53706
(520) 621-5444 (608) 890-1236
Counsel for Amici Curiae Climate Scientists
(i)
TABLE OF CONTENTS
Page
TABLE OF AUTHORITIES . . . . . . . . . . . . . . . . . . . . . . . iii
INTEREST OF AMICI CURIAE . . . . . . . . . . . . . . . . . . . . 1
A.Perspective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
B. Background and Experience . . . . . . . . . . . . . . . . . . 3
SUMMARY OF ARGUMENT . . . . . . . . . . . . . . . . . . . . . 9
ARGUMENT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
I. The Science of Climate Change Indicates that It Is
Virtually Certain that Greenhouse Gas Emissions
from Human Activities Cause Global Climate
Changes, Endangering Human Health and Welfare
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
II. EPA and the Court of Appeals Mischaracterized the
Science of Climate Change, Making It Appear More
Uncertain Than It Actually Is . . . . . . . . . . . . . . . . 17
A.EPA’s Decision . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
B. Court of Appeals Decision . . . . . . . . . . . . . . . . . . . 22
III. EPA Did Not Apply the Standard of Scientific
Evidence Set Forth in the Clean Air Act . . . . . . . 23
A. Section 202 Requires Reasonable Anticipation of
Endangerment to Public Health or Welfare, Not
Absolute Scientific Certainty . . . . . . . . . . . . . . . . . 24
(ii)
B. There Was and Is Sufficient Scientific Evidence to
Enable EPA to Make a Determination Under Section
202 of the Clean Air Act That Greenhouse Gas
Emissions “May Reasonably Be Anticipated to
Endanger Public Health or Welfare.” . . . . . . . . . . 27
CONCLUSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
(iii)
TABLE OF AUTHORITIES
Cases Page
Ethyl Corp. v. EPA, 541 F.2d 1 (D.C. Cir. 1976) . . . . 25-26
Hartford Fire Ins. Co. v. California, 509 U.S. 764 (1993) . 24
Murray v. Schooner Charming Betsy, 6 U.S. 64 (1804) . . 24
Massachusetts v. EPA, 415 F.3d 50
(D.C. Cir. 2005) . . . . . . . . . . . . . . . . . . . . . . . . . . . 3, 22, 25
Spector v. Norwegian Cruise Line, Ltd.,
545 U.S. 119 (2005) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Victor v. Nebraska, 511 U.S. 1 (1994) . . . . . . . . . . . . . . . . 23
Weinberger v. Rossi, 456 U.S. 25 (1982)) . . . . . . . . . . . . . . 24
Constitution, Statutes, Administrative,
and Other Legal Materials
U.S. Const. Art. VI, § 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Clean Air Act, 42 U.S.C. 7401-7671q,
§ 202(a)(1), 42 U.S.C. 7521(a)(1) . . 9-11, 20-21, 23-26, 30
42 U.S.C. 1857f-6c(c)(1)(A), currently
codified as amended at 42 U.S.C. 7545(c)(1)(A) . . . . . 25
Control of Lead Additives in Gasoline, 38 Fed.
Reg. 33,734 (Dec. 6, 1973) . . . . . . . . . . . . . . . . . . . . . . . . 25
Control of Emissions From New Highway
Vehicles and Engines, 68 Fed. Reg. 52,922
(Sept. 8, 2003) . . . . . . . . . . . . . . . . . . . . . . . . . . 3, 18-21, 29
(iv)
Constitution, Statutes, Administrative,
and Other Legal Materials (cont’d) Page
United Nations Framework Convention on Climate
Change, May 9, 1992, 1771 U.N.T.S. 107 . . . . . . . . . . . 24
Miscellaneous
Erica Beecher-Monas, The Heuristics of Intellectual Due
Process: A Primer for Triers of Science, 75 N.Y.U. L. Rev.
1563 (2000) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
J.C. Comiso, Arctic Warming Signals from Satellite
Observations, 61-3 Weather 70 (2006) . . . . . . . . . . . . . . 16
Dan B. Dobbs, The Law of Torts § 19 (2000) . . . . . . . . . . 23
J. Hansen, M. Sato, R. Ruedy, K. Lo, D.W. Lea & M.
Medina-Elizade, Global Temperature Change, Proc. Natl.
Acad. Sci. (forthcoming) . . . . . . . . . . . . . . . . . . . . . . . . 16
Emma J. Hutchinson & Peter J. G. Pearson, An Evaluation
of the Environmental and Health Effects of Vehicle Exhaust
Catalysts in the United Kingdom, 112 (2) Envtl. Health
Persp. (Feb. 2004) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Intergovernmental Panel on Climate Change, Technical
Summary of the Working Group I Report of the
Intergovernmental Panel on Climate Change (2001 ) 10-11,13
Joint Science Academies’ Statement: Global Response to Climate
Change (June 2005) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
National Academy of Sciences/National Research Council,
Surface Temperature Reconstructions for the Last 2,000 Years
(2006) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
(v)
Miscellaneous (cont’d) Page
National Academy of Sciences/National Research Council,
Abrupt Climate Change: Inevitable Surprises (2002) . passim
National Academy of Sciences/National Research Council,
Climate Change Science: An Analysis of Some Key Questions
(2001) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . passim
Isaac Newton, Principia Mathematica Philosophiae Naturalis
(W.A. Kaminski trans., World Sci. 1987) (1729) . . . . . 19
Robert C. Power, Reasonable and Other Doubts, 67 Tenn. L.
Rev. 45 (1999) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Susan E. Schober, Lisa B. Mirel, Barry I. Graubard, Debra
J. Brody, & Katherine M. Flegaldoi, Blood Lead Levels and
Death from All Causes, Cardiovascular Disease, and Cancer:
Results from the NHANES III Mortality Study, 10.1289
Envtl. Health Persp. 9123 (2006) . . . . . . . . . . . . . . . . . . 26
U.S. Climate Change Science Program, Temperature Trends
in the Lower Atmosphere: Steps for Understanding and
Reconciling Differences 1 (Apr. 2006) . . . . . . . . . . . . . . . 17
1 All parties have consented to the filing of this brief. Pursuant to
this Court’s Rule 37.6, Amici state that no counsel for any party in this
case authored this brief in whole or in part, and no person other than
Amici and their counsel has made a monetary contribution to the
preparation and submission of this brief.
2 The Climate Scientists are appearing in their individual capacity
and not as representatives of any institution with which any of them
is affiliated. The assertions of science in this brief have been drafted,
reviewed and approved by the Climate Scientists, representing a
distillation of the conclusions set forth in Climate Change Science and
other scientific reports cited herein.
3 “The National Academy of Sciences (“NAS”) is a private, nonprofit,
self-perpetuating society of distinguished scholars engaged in
scientific and engineering research, dedicated to the furtherance of
science and technology and to their use for the general welfare. Upon
the authority of a charter granted to it in 1863, the Academy has a
mandate that requires it to advise the federal government on scientific
and technical matters.” J.A. 140, National Academy of
Sciences/National Research Council, Preface to Climate Change Science:
An Analysis of Some Key Questions (2001) [“Climate Change Science” or
“NAS/NRC 2001 Report”].
INTEREST OF THE AMICI CURIAE1
Amici Curiae Climate Scientists are David Battisti,
William E. Easterling, Christopher Field, Inez Fung, James
E. Hansen, John Harte, Eugenia Kalnay, Daniel Kirk-
Davidoff, Pamela A. Matson, James C. McWilliams, Mario
J. Molina, Jonathan T. Overpeck, F. Sherwood Rowland,
Joellen L. Russell, Scott R. Saleska, Edward Sarachik, John
M. Wallace, and Steven C. Wofsy (hereinafter “Climate
Scientists”).2 The Climate Scientists are individual climate
scientists who are actively involved in research on changes
to the Earth’s climate that are being caused by
anthropogenic emissions of carbon dioxide, methane,
nitrous oxide, sulfur hexafluoride, hydrofluorocarbons,
and perfluorocarbons (“greenhouse gases” or “GHGs”)
and the effects of those changes. Most of these scientists
are members of the National Academy of Sciences
(“NAS”)3 or Engineering, or have served on one or more
of the recent National Academy of Sciences/National
Research Council (“NAS/NRC”) panels that have
2
4 Id.; National Academy of Sciences/National Research Council,
Abrupt Climate Change: Inevitable Surprises (2002) [“Abrupt Climate
Change” or “NAS/NRC 2002”]; National Academy of Sciences/
National Research Council, Surface Temperature Reconstructions for the
Last 2,000 Years (2006) [“NAS/NRC 2006”].
5 J.A. 213, Climate Change Science at 27 (reprinting Letter from John M.
Bridgeland & Gary Edson to Bruce Alberts (May 11, 2001)).
reviewed the state of the science on climate change and the
impacts of human activities on climate.4 The first of these,
Climate Change Science: An Analysis of Some of the Key
Questions (“Climate Change Science”or “NAS/NRC 2001)”),
was published in 2001 in response to a request from the
White House for an assessment of the areas of greater and
lesser certainty in climate change science.5 The second,
Abrupt Climate Change: Inevitable Surprises (“Abrupt Climate
Change” or “NAS/NRC 2002”) was published one year
later. The third, Surface Temperature Reconstructions for the
Last 2,000 Years (“Reconstructions” or “NAS/NRC 2006”),
was published this year in response to a request from
Congress. The NRC, the Academy’s principal operating
arm, was formed in 1916 to further scientific and
technological knowledge and to advise the federal
government. J.A. 140, preface to Climate Change Science.
A. Perspective
As practicing scientists who study the earth’s climate
system, we and many in our profession have long
understood that continued human-caused emission of
greenhouse gases—primarily carbon dioxide (CO2), but
also methane (CH4), nitrous oxide (N2O), and
fluorocarbons—would eventually warm the earth’s
surface. Most were skeptical that we would see strong
signs of human-induced climate change in our lifetimes.
But by the beginning of this decade, we observed that
global temperatures are rising, plant and animal ranges
are shifting, glaciers are in retreat globally, and arctic sea
ice is retreating. Sea levels are rising and the oceans are
becoming more acidic. To the extent that these changes
3
result from human alteration of the atmosphere, we know
that they are just the first small increment of climate
change yet to come if human societies do not curb
emissions of greenhouse gases.
The evidence of these changes, though attended by the
uncertainty or caveats that appropriately accompany
scientific knowledge, is nonetheless so compelling that it
has crystallized a remarkable consensus within the
scientific community: climate warming is happening, and
human activities are very likely a significant causal factor.
The nature of this consensus may be obscured in a public
debate that sometimes equates consensus with unanimity
or complete certainty. We are profoundly troubled by the
misunderstanding or misrepresentation of the current
state of knowledge of climate change evident in the United
States Environmental Protection Agency’s (“EPA’s”)
denial of the petition for rulemaking to regulate emissions
of greenhouse gases from mobile sources, Pet. App. A59-
A93, Control of Emissions From New Highway Vehicles
and Engines, 68 Fed. Reg. 52,922, (Sept. 8, 2003), and the
subsequent court of appeals review of that action, Pet.
App. 1-58, Massachusetts v. EPA, 415 F.3d 50 (D.C. Cir.
2005).
EPA and the appeals court stated that they considered
the NAS/NRC report Climate Change Science to be the
scientific authority for the decision to deny the petition to
regulate. We feel an obligation to inform this Court that
they misunderstood or misrepresented the science
contained in this report, to correct the public record as to
what Climate Change Science and subsequent NAS reports
say about climate change, and to offer our professional
insight on using scientific evidence to judge whether a
particular standard for regulatory action is met in the
matter of climate change.
B. Background and Experience
Amicus David Battisti is the Tamaki Professor of
Atmospheric Sciences at the University of Washington.
4
He has a Ph.D. from the University of Washington in the
field of atmospheric sciences. He has been involved in the
field of climate dynamics and climate change since 1984.
His research involves climate variability (El Niño, drought
in the Sahel, decadal variability in the climate system),
paleoclimate (abrupt climate change during the last glacial
period), and climate change. He served for three years on
the NAS Committee for Climate Research and for six years
was co-chair of the U.S. Climate Variability and
Predictability Science Steering Committee.
Amicus William E. Easterling is Professor of Geography
and Earth System Science at The Pennsylvania State
University. He also directs the Penn State Institutes of the
Environment. He received his B.S. (1976), M.S. (1980), and
Ph.D (1984) degrees in geography from the University of
North Carolina at Chapel Hill. Dr. Easterling is an expert
on the implications of climate change for global and
regional food security, including the potential for
agricultural systems to adapt to such change. He has
served on several panels and committees of the National
Research Council, including chairing the Panel on the
Human Dimensions of Seasonal-to-Interannual Climate
Variability. He has served on numerous government
advisory committees and task forces.
Amicus Christopher Field is the founding director of the
Department of Global Ecology of the Carnegie Institution
of Washington and Professor of Biological Sciences at
Stanford University. He has a Ph.D. from Stanford
University in the field of biological sciences. He has been
involved in the study of climate change impacts and the
global carbon cycle since 1988. He is a member of the NAS.
Amicus Inez Fung is Professor of Atmospheric Science
and Co-Director of the Berkeley Institute of the
Environment at the University of California (“U.C.”) at
Berkeley. Dr. Fung received her Sc.D. from the
Massachusetts Institute of Technology (“MIT”). Her
research expertise is in large scale numerical modeling of
biogeochemical cycles and their interaction with climate.
Her research also includes climate change, remote sensing
5
of earth systems, investigations of atmosphere-ocean
interactions, and atmosphere-biosphere interactions. She
is a member of the NAS and served on the NAS/NRC’s
Committee on Climate Change Science that reviewed the
state of climate science for President Bush and produced
Climate Change Science.
Amicus James E. Hansen is head of the NASA Goddard
Institute for Space Studies. Dr. Hansen received his Ph.D.
from the University of Iowa. His research interests include
radiative transfer in planetary atmospheres, development
of global climate models, current climate trends from
observational data, and projections of man’s impact on
climate. He is a member of the NAS and served on the
NAS/NRC’s Committee on Climate Change Science that
reviewed the state of climate science for President Bush
and produced Climate Change Science.
Amicus John Harte is a Professor in the Energy and
Resources Group and the Ecosystem Sciences Division of
the College of Natural Resources at the U.C. Berkeley. He
received a B.A. in physics from Harvard University in 1961
and a Ph.D. in theoretical physics from the University of
Wisconsin in 1965. He has been involved in the study of
earth system science since 1973 and his research currently
focuses on the ecological consequences of climate change
and the climate consequences of ecological changes. He
has served on six different panels of the NAS/NRC.
Amicus Eugenia Kalnay is a Distinguished University
Professor at the University of Maryland. Previously, she
was Director of the Environmental Modeling Center at the
National Weather Service and Head of the Global
Modeling Branch at the NASA Goddard Space Flight
Center. She has a Ph.D. in meteorology from MIT. Her
research expertise is in numerical modeling of the
atmosphere, data assimilation and predictability, El Niño
prediction, and applications of satellite remote
measurements to weather and climate problems. She is a
member of the National Academy of Engineering, and has
served on many panels of the NAS/NRC.
6
Amicus Daniel Kirk-Davidoff is an Assistant Professor
in the Department of Meteorology at the University of
Maryland. He received a Ph.D. in Meteorology from MIT
in 1997. He is a climate dynamicist with interests in the
stratospheric water vapor budget, paleoclimate modeling,
satellite climate monitoring, and the use of satellite data to
improve climate models.
Amicus Pamela A. Matson is the Richard and Rhoda
Goldman Professor of Environmental Studies at Stanford
University. She has been involved in the study of global
change for more than 20 years, focusing on land use
change, greenhouse gas production from agricultural
ecosystems, and interactions of forest and agricultural
ecosystems with the atmosphere and water. She has
served on the NRC’s Board on Global Change, and is
currently co-chair of the NAS Roundtable on Science and
Technology for Sustainability.
Amicus James C. McWilliams is the Louis Slichter
Professor of Earth Sciences at University of California, Los
Angeles. He has a Ph.D. from Harvard University in the
field of applied mathematics. He has been involved in the
study of oceanic and atmospheric circulations and climate
since 1970. He is a member of the NAS and a Fellow of the
American Geophysical Union. He served on the
NAS/NRC’s Committee on Climate Change Science that
reviewed the state of climate science for President Bush
and produced Climate Change Science.
Amicus Mario J. Molina is a Professor at the University
of California, San Diego (UCSD), with a joint appointment
in the Department of Chemistry and Biochemistry and the
Scripps Institution of Oceanography. Prior to joining
UCSD he was an Institute Professor at MIT. He received
a Ph.D. in Physical Chemistry from the University of
California, Berkeley. He has been involved in developing
our scientific understanding of the chemistry of the
stratospheric ozone layer and its susceptibility to
human-made perturbations. He was a co-author, with F.
Sherwood Rowland, of the 1974 publication in the British
journal Nature, on the threat to the ozone layer from
7
chlorofluorocarbon (CFC) gases, and received the 1995
Nobel Prize in Chemistry (with F. Sherwood Rowland and
Paul Crutzen) for his “work on atmospheric chemistry,
particularly concerning the formation and decomposition
of ozone.” He has served on the President’s Committee of
Advisors in Science and Technology, and on many other
advisory boards and panels. He is a member of the NAS,
the Institute of Medicine, and the Pontifical Academy of
Sciences. He has received numerous awards for his
scientific work in addition to the 1995 Nobel Prize in
Chemistry, including the Tyler Ecology and Energy Prize
in 1983 and the UNEP-Sasakawa Award in 1999.
Amicus Jonathan T. Overpeck is a Professor of
Geosciences and a Professor of Atmospheric Sciences at
the University of Arizona. He has a Ph.D. from Brown
University in the field of geological sciences. He has been
involved in the study of climate science since 1979. His
research focuses on using models and the climate record
of the past million years to understand climate variability
and future change. He served on the NAS/NRC
Committee that reviewed the state of climate science for
President Bush and produced Abrupt Climate Change.
Amicus F. Sherwood Rowland is the Bren Research
Professor of Chemistry and Earth System Science at U.C.
Irvine. He has a Ph.D. in Chemistry from the University
of Chicago in the field of Physical Chemistry. He was a
co-author, with Mario Molina, of the 1974 publication in
the British journal Nature, on the threat to the ozone layer
from CFC gases, and received the 1995 Nobel Prize in
Chemistry (with Mario Molina and Paul Crutzen) for his
“work on atmospheric chemistry, particularly concerning
the formation and decomposition of ozone.” He is a
member of the NAS and the Institute of Medicine, and is
a Foreign Member of the Royal Society (UK). He served
for eight years as the Foreign Secretary of the NAS, and
has received the Roger Revelle Medal of the American
Geophysical Union, and the Debye Award of the
American Chemical Society. He has received numerous
prizes for his scientific work on the environment including
8
the Japan Prize in Environmental Science and Technology
and the Tyler Prize in Ecology and Energy. He is a
member of the Board on Atmospheric Sciences and
Climate of the NRC, and served on the NAS/NRC’s
Committee on Climate Change Science that reviewed the
state of climate science for President Bush and produced
Climate Change Science.
Amicus Joellen L. Russell is an Assistant Professor of
Geosciences at the University of Arizona. She received her
B.A. in Environmental Geoscience from the Department of
Earth and Planetary Sciences at Harvard University in
1993, and her Ph.D. in Oceanography from the Scripps
Institution of Oceanography at UCSD in 1999. Her
research focuses on biogeochemical dynamics, the
interactions between the biological, geological and
chemical components of Earth’s environment.
Amicus Scott R. Saleska is an Assistant Professor of
Ecology and Evolutionary Biology at the University of
Arizona. He received a B.S. in Physics from MIT in 1986
and a Ph.D. in Energy and Resources from the U.C.
Berkeley in 1998. His research focuses on how climate
interacts with plant physiology, demography, and
ecological processes to influence or control biogeochemical
cycling from local to global scales.
Amicus Edward Sarachik is a professor in the
Department of Atmospheric Sciences and an adjunct
professor in the School of Oceanography at the University
of Washington. He served on the NAS/NRC Committee
on Climate Change Science that reviewed the state of
climate science for President Bush and produced Climate
Change Science.
Amicus John M. Wallace is a Professor in the
Department of Atmospheric Sciences at the University of
Washington. He has a Ph.D. from MIT in the field of
meteorology. He has been involved in the study of climate
variability and change since 1980 and his research involves
El Niño and other patterns of climate variability. He
served on the NAS/N RC’s Committee on Climate Change
Science that reviewed the state of climate science for
9
President Bush and produced Climate Change Science. He
is a member of the NAS and served on both the
NAS/NRC Committee that produced Abrupt Climate
Change and the NAS/NRC committee that produced the
report Reconstructions.
Amicus Steven C. Wofsy is the Abbott Lawrence Rotch
Professor of Atmospheric and Environmental Science at
Harvard University. He has a Ph.D. in Chemistry from
Harvard University and has studied atmospheric science
since 1971, concentrating on the processes that control
atmospheric chemical composition, climate change, and
the global carbon cycle. He has served on the NASA
Advisory Council and many other Federal advisory
committees, and was a principal author of the U.S. Carbon
Cycle Science Plan.
SUMMARY OF ARGUMENT
The science of climate change indicates that increases in
greenhouse gases will almost certainly affect global
climate and pose risks to human societies. The NAS/NRC
2001 report, Climate Change Science, comprehensively
addressed the centrally relevant questions of climate
change science, and unambiguously concluded that
Earth’s climate is changing in ways that risk significant
adverse impacts on public welfare. The NAS/NRC report
found strong evidence for anthropogenic causation of
recent climate change by emissions of CO2 and other
greenhouse gases, and stated that there is a high
probability for much larger human-caused climate
changes in the future.
EPA claimed to rely on Climate Change Science as its sole
scientific authority in denying petitioners’ request to
regulate GHG emissions under Section 202(a)(1) of the
Clean Air Act. However, EPA misrepresented the findings
of Climate Change Science by selectively quoting statements
about uncertainty while ignoring statements of certainty
and near-certainty, thus giving the appearance of far more
10
6 By “protective standard,” we refer to measures taken to protect
against possible danger or failure. Should EPA regulate GHGs today,
the principal effect would be to mitigate harm expected to occur
decades hence, not to reduce the impacts of GHGs already emitted.
7 In our discussion of climate change science, we use the terminology
introduced by Intergovernmental Panel on Climate Change Third
Assessment Report. Intergovernmental Panel on Climate Change
fundamental uncertainty than stated in the NAS/NRC
report. EPA then concluded that “it is inappropriate to
regulate GHG emissions from motor vehicles” “until more
is understood about the causes, extent, and significance of
climate change,” implying that there is no risk in waiting
for future research, a conclusion sharply inconsistent with
the plain language of Climate Change Science.
In fact, Climate Change Science establishes that there was
and is sufficient scientific evidence to enable EPA to make
a determination under Section 202 (a)(1) of the Clean Air
Act that greenhouse gas emissions “may reasonably be
anticipated to endanger public health or welfare.” Given
the protective standard of environmental regulation that
Congress codified in Section 202(a)(1),6 the scientific
evidence of the risks, long time lags, and irreversibility of
climate change argue persuasively for prompt regulatory
action to restrain emissions of greenhouse gases under the
Clean Air Act.
ARGUMENT
I. The Science of Climate Change Indicates that It Is
Virtually Certain that Greenhouse Gas Emissions
from Human Activities Cause Global Climate
Changes, Endangering Human Health and Welfare.
Neither EPA nor the court of appeals correctly applied
the science of climate change to the petition for
rulemaking. In its report in 2001, Climate Change Science,
a panel of NAS/NRC unambiguously stated that it is
virtually certain7 that greenhouse gas emissions from
11
[“IPCC”], Technical Summary of the Working Group I Report of the
Intergovernmental Panel on Climate Change 28 n.4 (2001) (“In this
Technical Summary and in the Summary for Policymakers, the
following words have been used where appropriate to indicate
judgmental estimates of confidence: virtually certain (greater than 99%
chance that a result is true); very likely (90-99% chance); likely (66-90%
chance); medium likelihood (33-66% chance); unlikely (10-33%
chance); very unlikely (1-10% chance); exceptionally unlikely (less than
1% chance). The reader is referred to individual chapters for more
details.”).
8 Water vapor is a greenhouse gas and is an important amplifier of
climate change because its atmospheric concentrations tend to increase
when the atmosphere and surface waters warm up. Anthropogenic
emissions of water vapor to the atmosphere by automobiles and other
combustion sources do not significantly affect global atmospheric
concentrations of water vapor relative to the natural evaporation and
condensation processes, and thus they do not “cause, or contribute,”
to pollution implicated in anthropogenic climate change. 42 U.S.C.
7521(a)(1) .
human activities cause global climate changes. These
emissions increase the risk of adverse effects on health and
welfare. To aid this Court in understanding the foregoing
conclusion, we first clarify what scientific knowledge
informs us about anthropogenic climate change.
1. The basic physics underlying the greenhouse effect
is firmly established. Two principles in particular are as
certain as any phenomena in planetary sciences. First,
particular atmospheric gases (“greenhouse gases”) absorb
radiation that otherwise would be lost to space, and
re-radiate it back to the ground. A planet with those gases
in its atmosphere is thus warmer at the surface than it
would be without them. Second, greater atmospheric
concentrations of greenhouse gases, all other things being
equal, cause higher temperatures at the surface. The Earth
is habitable for its current life forms in part because
natural levels of greenhouse gases in the atmosphere
warm the surface.
2. Over the last two centuries, it is virtually certain that
human activities have increased amounts of important
greenhouse gases (primarily CO2, CH4, N2O, and
fluorocarbons8) in the atmosphere to levels not seen in all
12
9 See note 7 supra.
of prior human experience, and likely not seen for 3
million years.
3. It is likely or very likely9 that human-induced
increases in these greenhouse gases are already causing
global climate to warm. Human activities likely caused
most of the approximately 0.6 oC (1.1 oF) rise over the 20th
century. J.A. 151, Climate Change Science at 1. The mean
ocean temperature has risen by 0.05 oC (0.09 oF), global
average sea level has risen by 0.1 to 0.2 meters (1/3 to 2/3
feet) over the 20th century, and snow cover and Arctic ice
have decreased by about 10% and 10-15%, respectively,
since the late 1960s (when data first became available for
this measurement). Id. at 16. A variety of other climate
factors are changing consistent with warming induced by
greenhouse gases. By contrast, we know of no measures
of climate on the global scale that indicate cooling.
4. It is virtually certain that what has been observed so
far is only the beginning, and that continued greenhouse
gas emissions along current trajectories will cause
additional warming of the earth system as a whole. The
average time for removal from the atmosphere of added
carbon dioxide is measured in centuries. It is very likely
that such perturbation would cause the rate of surface
warming and sea level rise in the 21st century to be
substantially larger and faster than that experienced in the
20th century, without precedent in the past 10,000 years.
5. The first sentences of Climate Change Science state:
Greenhouse gases are accumulating in Earth’s
atmosphere as a result of human activities, causing
surface air temperatures and subsurface ocean
temperatures to rise. Temperatures are, in fact,
rising. The changes observed over the last several
decades are likely mostly due to human activities,
but we cannot rule out that some significant part of
these changes is also a reflection of natural
variability. Human-induced warming and associated
sea level rises are expected to continue through the
13
21st century. Secondary effects are suggested by
computer model simulations and basic physical
reasoning. These include increases in rainfall rates
and increased susceptibility of semi-arid regions to
drought. The impacts of these changes will be
critically dependent on the magnitude of the
warming and the rate with which it occurs.
J.A. 151, Climate Change Science at 1.
6. Although the general link between increased
greenhouse gases in the atmosphere and increased
warming of the earth system is virtually certain, the
complexity of the climate system means that predictions of
specific details that follow from this general link are
subject to varying degrees of certainty. Among the more
certain predictions are the following:
a. It is likely, based on both models and on data from
the ice ages over the last 400,000 years, that if atmospheric
carbon dioxide doubled from pre-industrial times, and
rose no further, the long-term rise of global average
surface temperature (the “climate sensitivity”) would be
between 1.5 and 4.5 oC (2.7 – 8.1 oF). J.A. 166, Climate
Change Science at 7.
b. In the absence of emissions reductions, however,
carbon dioxide concentrations in the atmosphere are very
likely to increase to much more than twice pre-industrial
values, and the consequent rise in global average
temperature during the 21st century, projected to be 1.4 to
5.8 oC (2.5 to 10.4 oF), will likely continue to higher values
beyond the year 2100. IPCC, Technical Summary, at 69.
c. This amount of warming in 6.a and 6.b is very likely
to drive melting of arctic ice sheets and further increases
in global average sea level by 2100, with continued sealevel
rise in the decades and centuries following 2100.
d. The anticipated sea level rise, especially when
combined with likely increases in hurricane intensities,
would exacerbate storm surges and have direct, negative
impacts on health and welfare in the United States, and
globally. These negative impacts would be concentrated in
14
low-lying coastal regions, such as Cape Cod,
Massachusetts, the Gulf coast, and southern Florida.
e. Rising temperatures are also likely to lead to
increases in extreme weather events (especially heat
waves, and associated heat-related deaths) and altered
patterns of rainfall (e.g., droughts and floods) that will
disrupt natural and agricultural ecosystems, and increase
the risk of extinction of animal and plant species.
f. Ocean acidity is very likely to increase by several
tenths of a pH unit due to continued uptake of carbon
dioxide, and this acidification is likely to cause substantial
stress to key marine organisms, and hence to whole
marine ecosystems, particularly in cold water regions.
Although this is an impact of increasing levels of
greenhouse gases, it is not an atmospheric climate change
and therefore was not addressed in Climate Change Science.
g. Ground level ozone (“smog”) levels (and associated
risks to human health) are very likely to increase with
temperature, especially in the Northeastern United States,
where many areas currently experience ozone levels that
exceed EPA Clean Air Act standards on hot summer days.
7. The possibilities of the climate changes above have
been carefully and extensively assessed, and there is a
broad scientific consensus that these changes are likely or
very likely. This consensus is clearly expressed in Climate
Change Science. It is harder to determine how long it may
take for these changes to occur, and what the precise
magnitude of the impacts may be. The climate system has
a great deal of inertia (especially in the ice sheets and
oceans), and thus the effects of greenhouse gases already
in the atmosphere are delayed. Emissions of GHGs
commit the climate to future warming long after release to
the atmosphere.
8. Apart from the likely, very likely, and virtually
certain gradual climate changes outlined in points 1-7,
there is also an as yet unquantifiable probability that
continued greenhouse gas emissions will trigger abrupt
climate change surprises that could very rapidly impose
large impacts on ecosystems and human welfare and
15
health. The NAS/NRC issued a detailed report (Abrupt
Climate Change) on this matter in 2002, showing that
abrupt climate changes (e.g., large regional cooling or
warming, widespread droughts, shifts in hurricane
frequency or flood regimes that occur in only a decade or
so) are possible because they have happened in the past,
at the dawn of human history and before. We do not
understand these switches very well, but there is a finite
but unknown risk that continued emission of greenhouse
gases will trigger a climate change surprise.
9. The science of climate change (including the
uncertainties) implies that delay in reducing greenhouse
gas emissions will very likely increase the risks to human
societies. Early steps to reduce greenhouse gas emissions
to levels below current trajectories will certainly reduce
the magnitude of climate change that would otherwise be
caused. Because of inertia in the climate system, it will be
many decades before effects of emission reductions are
realized.
10. Delaying reductions in greenhouse gas emissions
heightens the risk to human welfare because climate
inertia commits us to large-scale, long term (centuries)
climate change consequences before the exact nature of
those consequences can be known. The heightened risk of
delaying emissions reductions is clearly expressed in
Climate Change Science. J.A. 151-152, Climate Change Science
at 1.
11. Stratospheric ozone depletion and the Antarctic
“ozone hole” illustrate how both surprise and inertia may
increase the risks from unmitigated global environmental
change. Models predicted that the emission of
chlorofluorocarbons (CFCs) and other chlorinated
halocarbons by human activities would gradually deplete
stratospheric ozone. No model predicted the stratospheric
ozone hole in advance of its discovery in the mid-1980s.
The reality of ozone depletion turned out to be worse than
even the worst-case modeled scenario because none of the
models anticipated the novel chemistry of ozone depletion
via polar stratospheric clouds above the south (and north)
16
10 See, e.g., Joint Science Academies’ Statement: Global Response to Climate
Change, available at http://www.nationalacademies.org/onpi/
06072005.pdf (June 2005) (signed by the presidents of the national
scientific academies in Brazil, Canada, China, France, Germany, India,
Italy, Japan, Russia, United Kingdom, and the United States). The
Statement begins:
Climate change is real. There will always be uncertainty in
understanding a system as complex as the world’s climate.
However there is now strong evidence that significant global
warming is occurring. The evidence comes from direct
measurements of rising surface air temperatures and subsurface
ocean temperatures and from phenomena such as increases in
average global sea levels, retreating glaciers, and changes to
many physical and biological systems. It is likely that most of
the warming in recent decades can be attributed to human
activities (IPCC 2001). This warming has already led to changes
in the Earth’s climate.
Id. (emphasis added).
11 J. Hansen, M. Sato, R. Ruedy, K. Lo, D.W. Lea & M.
Medina-Elizade, Global Temperature Change, Proc. Natl. Acad. Sci.
(forthcoming); J.C. Comiso, Arctic Warming Signals from Satellite
Observations, 61-3 Weather 70-76 (2006).
poles. The CFC phase-out of the 1990s should allow the
ozone hole to recover, but it will take about 75 years, a
time lag reflecting the long lifetimes of CFCs (inertia
preventing recovery). It is noteworthy that early regulation
by the United States (beginning in the 1970s, before the
ozone hole was discovered) certainly reduced the risks
and damages that unfolded in the case of stratospheric
ozone depletion.
12. Developments since the NAS/NRC reports of 2001
and 2002 have only reinforced the finding that recent
climate changes are “likely mostly due to human
activities.”10 J.A. 151, Climate Change Science at 1.
a. The five warmest years since pre-industrial times
were 1998, 2002, 2003, 2004, and 2005 (2005 is the warmest
overall), and the reduction of ice cover in the Arctic has
accelerated.11
b. A recent NAS/NRC report confirmed temperature
trends discussed in Climate Change Science, concluding that
the global mean surface temperature during the last few
17
decades of the 20th century was higher than any
comparable period in the past four centuries, and, likely
so, in the past 1000 years. Reconstructions at 2, Report in
Brief; id. at 3.
c. The question of the apparent discrepancy between
late 20th century temperature rise at the surface, versus
satellite-derived temperatures above the surface, regarded
as a puzzle in Climate Change Science, has been resolved. A
recent comprehensive scientific reevaluation, which
corrected errors in the initial satellite estimates, concluded
that “all available data sets show that both the surface and
the troposphere have warmed.” U.S. Climate Change
Science Program, Temperature Trends in the Lower
Atmosphere: Steps for Understanding and Reconciling
Differences 1 (Apr. 2006).
II. EPA and the Court of Appeals Mischaracterized the
Science of Climate Change, Making It Appear More
Uncertain Than It Actually Is.
EPA relied on the NAS/NRC 2001 report, Climate
Change Science, as the authoritative source of scientific
information in its decision to deny the petition for
rulemaking. The court of appeals cited no other source
than Climate Change Science for its conclusion regarding
scientific uncertainty. But EPA and the court of appeals
mischaracterized the scientific analysis in Climate Change
Science and arrived at conclusions sharply at variance with
the scientific judgments in the report.
To understand the magnitude of their
mischaracterization of Climate Change Science, one must
first examine the nature of scientific uncertainty. Scientific
knowledge is developed incrementally, using experiment
and observation to test and refine hypotheses. A large part
of the work of science is directed towards understanding
and quantifying uncertainties. The goal is to place bounds on
future outcomes. An hypothesis is deemed “virtually
certain” if the predicted outcome is expected to occur for
18
12 See note 7 supra .
13 See Erica Beecher-Monas, The Heuristics of Intellectual Due Process:
A Primer for Triers of Science, 75 N.Y.U. L. Rev. 1563, 1581 (2000)
(“Scientists understand that fluctuations, instability, multiple choices,
and limited predictability are inherent at all levels of observation.”)
(internal quotation marks omitted).
99% or more of repeated trials, “very likely” for 90-99%,
and “likely” for 66-90%.12 Absolute certainty is impossible
in principle in climate science, as in all fields of science.13
Moreover, there is only a single “trial” with respect to
earth’s climate, so strict statistical measures of likelihood
cannot be applied. These characteristics of scientific
knowledge must be expertly considered, and certainties
and uncertainties carefully balanced, when applying the
protective approach required for decisions to regulate
under the Clean Air Act. However, in its denial of the
petition for rulemaking, EPA presented an inexpert and
unbalanced discussion, and reached conclusions not
supported by the scientific evidence it was purporting to
use.
A. EPA’s Decision
EPA’s decision misrepresented the findings in Climate
Change Science, which EPA cited as the only source of
evidence in its discussion of scientific uncertainty. See Pet.
App. 82, 68 Fed. Reg. 52,922, 52,930 (Sept. 8, 2003) (“We
rely in this decision on NRC’s objective and independent
assessment of the relevant science.”); see also id. (adding
that nothing received during the public comment period
“causes us to question the validity of the NRC’s
conclusions”). Climate Change Science encompasses both
the more certain and the less certain elements of the
science, and uncertainties are described explicitly, as is the
norm in scientific reports. Thus, it is possible to quote
selectively from the report to make the scientific
conclusions appear either more or less certain than they
actually are.
19
EPA admitted to three important observations about the
global climate: (1) that “concentrations of GHGs are
increasing in the atmosphere as a result of human
activities,” id. (citing J.A. 170-180, Climate Change Science at
9-12), (2) that a “diverse array of evidence points to a
warming of global surface air temperatures,” id. (quoting
J.A. 190, Climate Change Science at 16), and (3) that “the
magnitude of the observed warming is large in
comparison to natural variability,” Pet. App. A83, 68 Fed.
Reg. at 52,930 (quoting J.A. 193, Climate Change Science at
17).
However, EPA omitted the essential scientific
conclusion that constitutes the core of Climate Change
Science: that these separate observations are causally
linked. This is a fundamental omission. It is as if a
summary of Newton’s Principia—which advanced the
theory of gravitation as the common explanation for how
apples fall to earth and planets move in the heavens—
repeated Newton’s description of the motions of apples
and planets, but never got around to mentioning gravity.
Isaac Newton, Principia Mathematica Philosophiae Naturalis
(W.A. Kaminski trans., World Scientific 1987) (1729).
EPA in particular omitted mention of the following two
pivotal conclusions. First, the NAS report unambiguously
links already observed climate warming, and related
impacts, damages, and risks, to human emissions of
greenhouse gases. “The changes observed over the last several
decades are likely mostly due to human activities, but we
cannot rule out that some significant part of these changes
is also a reflection of natural variability.” J.A. 151, Climate
Change Science at 1 (emphasis added). The key conclusion,
in the first part of this sentence, is never cited by EPA.
Second, after listing a number of impacts and damages
that are likely to occur in response to human-caused
climate change, Climate Change Science states, “Hence
national policy decisions made now, and in the longerterm
future will influence the extent of any damage
suffered by vulnerable human populations and
ecosystems later in this century.” J.A. 152, Climate Change
20
14 See note 7 supra.
Science at 1. Remarkably, EPA ignored this scientific
judgment, which clearly indicated the panel’s concern that
dangerous human-caused climate change is likely14
already underway with larger effects committed for the
future, particularly if action should not be taken to limit
emissions.
EPA focused instead on a statement in the 2001 report
that a “causal linkage between the buildup of greenhouse
gases in the atmosphere and the observed climate changes
during the 20th century cannot be unequivocally
established.” J.A. 193, Climate Change Science at 17 (cited in
Pet. App. A83, 68 Fed. Reg. at 52,930). But EPA was
petitioned to initiate rulemaking under Section 202(a)(1) of
the Clean Air Act, which requires regulation of motor
vehicle pollutants that “may reasonably be anticipated to
endanger public health or welfare.” 42 U.S.C. 7521(a)(1)
(emphasis added). It is not required that the link between
observed warming and increased greenhouse gas
concentrations be “unequivocally established” in order to
ascertain whether greenhouse gas emissions “may
reasonably be anticipated to harm” human health and
welfare under Section 202(a)(1). As noted above, if
“unequivocal” means “absolutely certain,” this is
impossible for climate science, just as absolute certainty is
impossible to show for the link between smoking and
cancer, or for the links to impacts of many other pollutants
that are already regulated under the “reasonably be
anticipated to endanger” framework.
EPA also ignored the two-sidedness of scientific
uncertainty. Outcomes may turn out better than our best
current prediction, but it is just as possible that
environmental and health damages will be more severe
than best predictions, as happened in the examples of
stratospheric ozone depletion (discussed supra) and of lead
toxicity from automobile emissions (discussed infra).
Thus, it is wrong to infer that, because a prediction of an
21
undesirable outcome is uncertain, the associated risks are
not worth regulating.
EPA’s use of selective quotations and its unbalanced
treatment of uncertainty allowed it to draw conclusions
that are opposed to the actual scientific conclusions of
Climate Change Science. EPA stated: “Substantial scientific
uncertainties limit our ability to assess each of these factors
[that contribute to climate change] and to separate out
those changes resulting from natural variability from those
that are directly the result of increases in anthropogenic
GHGs.” Pet. App. A84, 86 Fed. Reg. at 52,930. EPA’s
conclusion, drawn from this statement, was: “Until more
is understood about the causes, extent, and significance of
climate change and the potential options for addressing it,
EPA believes that it is inappropriate to regulate GHG
emissions from motor vehicles.” Pet. App. A86, 86 Fed.
Reg. at 52,931.
EPA’s conclusion implies that there is no significant risk
in waiting for future studies. This conclusion directly
conflicts with the plain language of Climate Change Science,
the authority that EPA claimed to use. The uncertainties
are important, but so are the certainties and nearcertainties,
and the risks of delaying reductions in GHG
emissions. In environmental science generally, and
climate science in particular, critical decisions must be
made in a timely fashion to protect the health and welfare
of the population, without absolute certainty or multiple
trials, and without the false luxury of waiting for the
damage to be observed.
The need for timely decisions in the presence of
uncertainty was recognized explicitly by Congress in
crafting the Clean Air Act 202(a)(1). Climate Change Science
assessed the science holistically and concluded that
human-caused climate change had most likely already
occurred and that serious future damage was highly
probable.
By failing to properly balance scientific knowledge and
uncertainties, and to acknowledge the links between
GHGs, climate change, and damage to human health and
22
welfare discussed in Climate Change Science, EPA
fundamentally distorted the meaning of the report. There
is simply no sign in EPA’s decision of the strong base of
scientific knowledge described in Climate Change Science.
The core conclusions of Climate Change Science (omitted in
EPA’s discussion) dovetail with the requirements of the
Clean Air Act § 202(a)(1). EPA’s denial of petition to
regulate was based on distortion and misrepresentation of
the scientific findings of Climate Change Science.
B. Court of Appeals Decision
The court of appeals assumed that EPA has the
statutory authority to regulate greenhouse gas emissions
from motor vehicles, but decided that EPA had properly
exercised its discretion in refusing to regulate these
emissions. In upholding EPA’s decision, the court of
appeals relied on several factors, including scientific
uncertainty. Pet. App. 12, Massachusetts, 415 F.3d at 57.
The court of appeals, relying on EPA’s misrepresentation
of Climate Change Science, also mischaracterizes the
findings of the NAS/NRC panel by emphasizing
uncertainties in climate change science while failing even
to mention the existence of fundamental areas of certainty
or consensus. The court then used scientific uncertainty
(which it had mischaracterized) as a basis for upholding
EPA’s decision. Pet. App. 13, id. at 58.
Judge Randolph’s opinion for the court cites Climate
Change Science six times, with these citations selected in a
way that omits important scientific context. For example,
the opinion states, “The National Research Council
[NAS/NRC] concluded that ‘a causal linkage’ between
greenhouse gas emissions and global warming ‘cannot be
unequivocally established,’” excluding the intervening
words “between the buildup of greenhouse gases in the
atmosphere and the observed climate changes in the 20th
century.” Pet. App. 12, id. at 57. Without the intervening
words, the reader is given the false impression that the
quote applies to a completely different issue, the general
23
15 See Dan B. Dobbs, The Law of Torts § 19 (2000) (“The plaintiff need
not prove that each fact necessary for her prima facie case is certainly
true or true beyond a doubt. Instead, she must prove that each fact is
more probable than not. Expressed statistically, she must persuade the
jury or other trier of fact that the likelihood of each fact in her case
exceeds 50%.”) (footnote omitted).
16 Victor v. Nebraska, 511 U.S. 1, 15 (1994) (requiring fact finder to
have “a subjective state of near certitude” to return a guilty verdict);
Robert C. Power, Reasonable and Other Doubts, 67 Tenn. L. Rev. 45,
51-53 (1999).
link between greenhouse gas concentrations and global
warming. In fact, as we (including those of us who were
members of the 2001 NAS/NRC panel) emphasize above,
this link is virtually certain, even though uncertainties
attach to the exact magnitude and timing of
human-induced climate warming.
III. EPA Did Not Apply the Standard of Scientific
Evidence Set Forth in the Clean Air Act.
The appropriate legal standard for determining the
sufficiency of scientific evidence depends on the legal
setting in which a decision is made. Different standards
are appropriate in different contexts, such as in civil cases
(“preponderance of the evidence”15) and criminal cases
(“beyond reasonable doubt”16).
In this case, the legal standard for the sufficiency of
scientific evidence has been established by Congress in
Section 202(a)(1) of the Clean Air Act. That section
provides:
The Administrator shall by regulation prescribe (and
from time to time revise) in accordance with the
provisions of this section, 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 his judgment cause, or contribute to, air pollution
which may reasonably be anticipated to endanger public
health or welfare.
24
17 The protective approach in Section 202(a)(1) is reinforced and
made more explicit for greenhouse gases by a treaty to which the
United States is a party, the United Nations Framework Convention
on Climate Change, May 9, 1992, 1771 U.N.T.S. 107, available at
http://unfccc.int/essential_background/convention/background
/items/1349.php, which entered into force in 1994, see UNFCCC
website at http://unfccc.int/parties_and_observers/parties/items
/2228.php. In ratifying the Convention, the parties expressly agreed
not to invoke scientific uncertainty as a ground for failing to take
regulatory action on greenhouse gases where there is a “threat” of
serious damage:
The Parties should take precautionary measures to anticipate,
prevent or minimize the causes of climate change and mitigate its
adverse effects. Where there are threats of serious or irreversible
damage, lack of full scientific certainty should not be used as a reason for
postponing such measures . . . .”
Id. at Art. 3, ¶ 3 (emphasis added). Ratified treaties, along with the
Constitution itself and United States laws, are “the supreme Law of the
Land.” U.S. CONST. Art. VI, § 2. Thus, an “act of Congress ought
never to be construed to violate the law of nations if any other possible
construction remains . . .” Murray v. Schooner Charming Betsy, 6 U.S. 64,
118 (1804); Weinberger v. Rossi, 456 U.S. 25, 32 (1982); Hartford Fire Ins.
Co. v. California, 509 U.S. 764, 814-815 (1993) (Scalia, J., dissenting);
Spector v. Norwegian Cruise Line, Ltd., 545 U.S. 119, ___, 125 S.Ct. 2169,
2185 (2005) (Ginsburg, J., concurring).
42 U.S.C. 7521(a)(1) (emphasis added). The following
explains the standard of scientific evidence established
under Section 202(a)(1) and how, in fact, the science of
climate change meets this standard.
A. Section 202 Requires Reasonable Anticipation of
Endangerment to Public Health or Welfare, Not
Absolute Scientific Certainty.
The text and purposes of the Clean Air require a
conservative approach to protection of public health and
welfare. The statute mandates regulation of pollutants
that “may reasonably be anticipated to endanger public
health or welfare,” 42 U.S.C. 7521(a)(1). It does not, and
cannot reasonably be read to require complete scientific
certainty in order to make a determination.17
25
18 The court of appeals in the instant case misread Ethyl to support
EPA’s reliance, in deciding not to regulate motor vehicle greenhouse
gas emissions, upon policy considerations unrelated to whether such
EPA’s decision to regulate lead additives in gasoline
illustrates the wisdom of Congress’ protective mandate to
protect public health and welfare in Clean Air Act
§ 202(a)(1). In 1973, EPA promulgated final regulations
phasing out the use of lead as a gasoline additive. Control
of Lead Additives in Gasoline, 38 Fed. Reg. 33,734 (Dec. 6,
1973). It acted under Section 211(c)(1)(A) of the Clean Air
Act, which at that time authorized EPA to adopt
regulations restricting fuel additives in gasoline if any of
their emission products “will endanger the public health
or welfare. . . .” 42 U.S.C. 1857f-6c(c)(1)(A), currently
codified as amended at 42 U.S.C. 7545(c)(1)(A). In
adopting these regulations, EPA found that auto emissions
from leaded gasoline presented “a significant risk of
harm” to public health. 38 Fed. Reg. at 33,734.
These regulations were promulgated notwithstanding
the lack of scientific consensus on whether the target of
EPA’s regulation—airborne lead from motor
vehicles—was correlated with elevated blood lead levels
(which cause lead poisoning and irreversible loss of
cognitive function), and, if it was, whether airborne lead
from burning leaded gasoline was a significant exposure
pathway relative to other pathways (e.g. lead-based paint).
38 Fed. Reg. at 33,736.
Nevertheless, EPA promulgated lead regulations in the
face of this uncertainty. As the court upholding EPA’s
decision to regulate recognized, certainty “may be
impossible to obtain if the precautionary purpose of the
statute is to be served.” Ethyl Corp. v. EPA, 541 F.2d 1, 28
(D.C. Cir. 1976). The “will endanger” language, the Ethyl
court said, is triggered when harm is threatened, not
simply when it has already occurred. 541 F.2d at 17. This
conclusion is supported, the court said, not only by the
text and legislative history of the Clean Air Act, but also
by EPA’s responsibility under the statute: “to protect the
public from danger.” Id. at 24.18
26
emissions meet the Section 202(a)(1) endangerment standard.
Massachussetts v. EPA, 415 F.3d 57-58. While Ethyl approved EPA’s
authority to make essentially “legislative policy judgments” under
statutory language nearly identical to that of Section 202, those
judgments were sharply limited to “the relative risks of
underprotection as compared to overprotection” and did not
encompass such far-flung considerations as whether unilateral
regulation of U.S. motor vehicle emissions could weaken efforts to
persuade developing countries to reduce their emissions of
greenhouse gases. See Ethyl, 541 F.2d at 20 (refuting industry’s
contention that the statute limited EPA to reliance upon specific
factual findings). Nothing in the treatment of Ethyl by the court of
appeals below cast aspersions upon Ethyl’s endorsement of a
protective interpretation of the Section 202(a)(1) trigger for regulation.
19 Pub. L. No. 95-95, § 401, 91 Stat. 791 (1977). Congress expressly
intended these changes to compel EPA to assess risks and undertake
regulatory action under conditions of uncertainty.
20 Susan E. Schober, Lisa B. Mirel, Barry I. Graubard, Debra J. Brody,
& Katherine M. Flegaldoi, Blood Lead Levels and Death from All Causes,
Cardiovascular Disease, and Cancer: Results from the NHANES III
Mortality Study, 10.1289 Envtl. Health Persp. 9123 (2006), available at
http://www.ehponline.org/members/2006/9123/9123.pdf (last
visited Aug. 24, 2006).
This protective interpretation of the Clean Air Act was
strengthened and codified by Congress’ subsequent
amendment of the Section 202(a)(1) to require EPA to
regulate where emissions “cause, or contribute to, air
pollution which may reasonably be anticipated to
endanger public health or welfare,” as opposed to the
more narrow wording that the pollution “will endanger”
public health or welfare.19
The outcome of regulating lead emissions was very
significant. After lead was removed from gasoline, blood
levels in children and adults dropped faster than
anticipated. Blood lead levels decreased from 12.8 μg/dL
in the late 1970s to 2.3 μg/dL in 1993 (geometric mean);
recent epidemiological studies show that adults who
carried the mean blood lead levels of the 1970s suffered an
increase in mortality (all causes) exceeding 40%, compared
to those having lead levels equal to current mean values.20
This startling impact could not be determined in the 1970s
because the entire population had elevated levels of lead,
27
21 Emma J. Hutchinson & Peter J. G. Pearson, An Evaluation of the
Environmental and Health Effects of Vehicle Exhaust Catalysts in the United
Kingdom, 112 (2) Envtl. Health Persp. (Feb. 2004).
22 We are not asking the Court to make an endangerment
determination, as that is properly the role of EPA. This brief provides
the Court with the Climate Scientists’ expert opinion that evidence
and because the studies had not covered a sufficiently long
period. Evidently huge impacts on health and welfare
accrued even though they could not be demonstrated
conclusively when EPA issued its ruling.
The timely EPA action removed lead from fuel at least
10 years before similar steps in Europe. In the United
Kingdom, lead removal began in 1993. It has been
estimated that removing lead from motor fuels delivered
a net societal saving of over $2 billion in the first 10 years
in the United Kingdom alone, accounting for mortality
changes but not including the costs of loss of cognitive
function and other effects of lead intoxication.21 But while
uncontrolled lead emissions continued in Europe and the
United Kingdom through the 1980s and early 1990s, the
United States was already applying the Clean Air Act’s
conservative science-based approach to curtail lead
emissions, evidently saving many billions of dollars and
protecting the health of tens of millions of people,
especially children.
B. There Was and Is Sufficient Scientific Evidence to
Enable EPA to Make a Determination Under
Section 202 of the Clean Air Act that Greenhouse
Gas Emissions “May Reasonably Be Anticipated
to Endanger Public Health or Welfare.”
EPA’s decision not to regulate GHG emissions never
directly addressed the fundamental question: does the
science of climate change support a determination that
GHG emissions “may reasonably be anticipated to
endanger public health or welfare”? We here explain why,
in our professional opinion as climate scientists, the
evidence supporting such a determination is compelling.22
28
exists to support an endangerment finding, so that a remand would
not be an empty gesture.
As stated in Climate Change Science, “national policy
decisions made now and in the longer term future will
influence the extent of any damage suffered by vulnerable
human populations and ecosystems later in this century.”
J.A. 152, Climate Change Science at 1.
The NAS/NRC report discusses many adverse impacts
of anthropogenic climate change, in addition to those
discussed supra:
The optimal climate for crops may change, requiring
significant regional adaptations. Some models
project an increased tendency toward drought over
semi-arid regions, such as the U.S. Great Plains.
Hydrologic impacts could be significant over the
western United States, where much of the water
supply is dependent on the amount of snow pack
and the timing of the spring runoff. Increased rainfall
rates could impact pollution run-off and flood
control. With higher sea level, coastal regions could
be subject to increased wind and flood damage even
if tropical storms do not change in intensity. A
significant warming also could have far reaching
implications for ecosystems.
J.A. 160-161, Climate Change Science at 4.
Climate is one of a number of factors influencing the
incidence of infectious disease. Cold related stress
would decline in a warmer climate, while heat stress
and smog induced respiratory illnesses in major
urban areas would increase, if no adaptation
occurred.
J.A. 160, Climate Change Science at 4.
Global warming could well have serious adverse
societal and ecological impacts by the end of this
century, especially if globally-averaged temperature
increases approach the upper end of the IPCC
29
23 The brief for respondent Utility Air Regulatory Group in
opposition to the petition for certiorari suggested that the existence of
some benefits from global warming and the economy’s ability to adapt
to adverse impacts would support a finding of non-endangerment
(UARG Br. in Opp. 12-13). In its decision, EPA cited only the existence
of scientific uncertainties regarding the extent of the impact and
development of new technologies. Pet. App. 82-85, 62 Fed. Reg. at
52,931.
24 Among the uncertainties that EPA cited was “[t]he fraction of fossil
fuel carbon that will remain in the atmosphere and contribute to
radiative forcing versus exchange with the oceans or with the land
biosphere.” Pet. App. 84, 62 Fed. Reg. at 52,930. But that uncertainty
is irrelevant to the question as to whether to regulate, because (1) a
significant portion of the emissions will accumulate in the atmosphere,
(2) to the extent that the emissions are taken up by the oceans they will
accumulate there and contribute to acidification and (3) in both cases,
waiting will exacerbate the damage. See pt. I, supra.
projections. Even in the more conservative scenarios,
the models project temperatures and sea levels that
continue to increase well beyond the end of this
century, suggesting that assessments that examine
only the next 100 years may well underestimate the
magnitude of the eventual impacts.
Id., Climate Change Science at 4.
These impacts are clearly sufficient to support a finding
of “reasonable anticipation” of endangerment. The fact
that the extent of the damage, or associated time lags, may
be greater or less than current projections were not (in the
judgment of the NAS/NRC panel) sufficient to cast doubt
on the links between GHGs and climate change with its
associated risks. That particular impacts may be more or
less uncertain, that the economy or public health system
might adapt, or that future research may reveal more
effective control technologies, are all irrelevant to the
statutory standard for triggering regulatory action.23
Protective considerations are particularly important for
greenhouse gases because, as explained in Part I, delaying
action to reduce greenhouse gas emissions will certainly
result in greater buildup of greenhouse gases in the
atmosphere,24 and thus we commit the earth to long30
lasting climate change and associated damages decades
before these damages can be measured. Reversing the
impacts of climate change becomes vastly harder, or
impossible, and more expensive as we allow greenhouse
gas pollutants to accumulate in the atmosphere. Thus
more than enough scientific evidence exists to warrant the
conclusion that greenhouse gas emissions “may
reasonably be anticipated to endanger public health or
welfare” under Section 202(a)(1).
CONCLUSION
For the foregoing reasons, this Court should reverse the
decision of the court of appeals.
Respectfully submitted,
JOHN C. DERNBACH ROBERT B. MCKINSTRY, JR.*
WIDENER UNIVERSITY PENN STATE UNIVERSITY
LAW SCHOOL 432 FOREST RESOURCES
3800 VARTAN WAY BUILDING
HARRISBURG, PA 17106 UNIVERSITY PARK, PA 16802
(717) 541-1933 (484) 467-3207
*Counsel of Record
KIRSTEN H. ENGEL STEPHANIE TAI
UNIVERSITY OF ARIZONA UNIVERSITY OF WISCONSIN
COLLEGE OF LAW LAW SCHOOL
1201 E. SPEEDWAY BLVD. 957 BASCOM MALL
TUCSON, AZ 85721 MADISON, WI 53706
(520) 621-5444 (608) 890-1236
Counsel for Amici Curiae Climate Scientists
August 31, 2006
