(Slip Opinion) OCTOBER TERM, 2006 1
Syllabus
NOTE: Where it is feasible, a syllabus (headnote) will be released, as is
being done in connection with this case, at the time the opinion is issued.
The syllabus constitutes no part of the opinion of the Court but has been
prepared by the Reporter of Decisions for the convenience of the reader.
See United States v. Detroit Timber & Lumber Co., 200 U. S. 321, 337.
SUPREME COURT OF THE UNITED STATES
Syllabus
MASSACHUSETTS ET AL. v. ENVIRONMENTAL PRO
TECTION AGENCY ET AL.
CERTIORARI TO THE UNITED STATES COURT OF APPEALS FOR
THE DISTRICT OF COLUMBIA CIRCUIT
No. 05–1120. Argued November 29, 2006—Decided April 2, 2007
Based on respected scientific opinion that a well-documented rise in
global temperatures and attendant climatological and environmental
changes have resulted from a significant increase in the atmospheric
concentration of “greenhouse gases,” a group of private organizations
petitioned the Environmental Protection Agency (EPA) to begin regu
lating the emissions of four such gases, including carbon dioxide, un
der §202(a)(1) of the Clean Air Act, which requires that the EPA
“shall by regulation prescribe . . . standards applicable to the emis
sion of any air pollutant from any class . . . of new motor vehicles . . .
which in [the EPA Administrator’s] judgment cause[s], or contrib
ute[s] to, air pollution . . . reasonably . . . anticipated to endanger
public health or welfare,” 42 U. S. C. §7521(a)(1). The Act defines
“air pollutant” to include “any air pollution agent . . . , including any
physical, chemical . . . substance . . . emitted into . . . the ambient
air.” §7602(g). EPA ultimately denied the petition, reasoning that
(1) the Act does not authorize it to issue mandatory regulations to
address global climate change, and (2) even if it had the authority to
set greenhouse gas emission standards, it would have been unwise to
do so at that time because a causal link between greenhouse gases
and the increase in global surface air temperatures was not un
equivocally established. The agency further characterized any EPA
regulation of motor-vehicle emissions as a piecemeal approach to cli
mate change that would conflict with the President’s comprehensive
approach involving additional support for technological innovation,
the creation of nonregulatory programs to encourage voluntary pri
vate-sector reductions in greenhouse gas emissions, and further re
search on climate change, and might hamper the President’s ability
2 MASSACHUSETTS v. EPA
Syllabus
to persuade key developing nations to reduce emissions.
Petitioners, now joined by intervenor Massachusetts and other
state and local governments, sought review in the D. C. Circuit. Al
though each of the three judges on the panel wrote separately, two of
them agreed that the EPA Administrator properly exercised his dis
cretion in denying the rulemaking petition. One judge concluded that
the Administrator’s exercise of “judgment” as to whether a pollutant
could “reasonably be anticipated to endanger public health or wel
fare,” §7521(a)(1), could be based on scientific uncertainty as well as
other factors, including the concern that unilateral U. S. regulation of
motor-vehicle emissions could weaken efforts to reduce other coun
tries’ greenhouse gas emissions. The second judge opined that peti
tioners had failed to demonstrate the particularized injury to them
that is necessary to establish standing under Article III, but accepted
the contrary view as the law of the case and joined the judgment on
the merits as the closest to that which he preferred. The court there
fore denied review.
Held:
1. Petitioners have standing to challenge the EPA’s denial of their
rulemaking petition. Pp. 12–23.
(a) This case suffers from none of the defects that would preclude
it from being a justiciable Article III “Controvers[y].” See, e.g., Lu
ther v. Borden, 7 How. 1. Moreover, the proper construction of a con
gressional statute is an eminently suitable question for federal-court
resolution, and Congress has authorized precisely this type of chal
lenge to EPA action, see 42 U. S. C. §7607(b)(1). Contrary to EPA’s
argument, standing doctrine presents no insuperable jurisdictional
obstacle here. To demonstrate standing, a litigant must show that it
has suffered a concrete and particularized injury that is either actual
or imminent, that the injury is fairly traceable to the defendant, and
that a favorable decision will likely redress that injury. See Lujan v.
Defenders of Wildlife, 504 U. S. 555, 560–561. However, a litigant to
whom Congress has “accorded a procedural right to protect his con
crete interests,” id., at 573, n. 7—here, the right to challenge agency
action unlawfully withheld, §7607(b)(1)—“can assert that right with
out meeting all the normal standards for redressability and immedi
acy,” ibid. Only one petitioner needs to have standing to authorize
review. See Rumsfeld v. Forum for Academic and Institutional
Rights, Inc., 547 U. S. 47, 52, n. 2. Massachusetts has a special posi
tion and interest here. It is a sovereign State and not, as in Lujan, a
private individual, and it actually owns a great deal of the territory
alleged to be affected. The sovereign prerogatives to force reductions
in greenhouse gas emissions, to negotiate emissions treaties with de
veloping countries, and (in some circumstances) to exercise the police
Cite as: 549 U. S. ____ (2007) 3
Syllabus
power to reduce motor-vehicle emissions are now lodged in the Fed
eral Government. Because congress has ordered EPA to protect Mas
sachusetts (among others) by prescribing applicable standards,
§7521(a)(1), and has given Massachusetts a concomitant procedural
right to challenge the rejection of its rulemaking petition as arbitrary
and capricious, §7607(b)(1), petitioners’ submissions as they pertain
to Massachusetts have satisfied the most demanding standards of the
adversarial process. EPA’s steadfast refusal to regulate greenhouse
gas emissions presents a risk of harm to Massachusetts that is both
“actual” and “imminent,” Lujan, 504 U. S., at 560, and there is a
“substantial likelihood that the judicial relief requested” will prompt
EPA to take steps to reduce that risk, Duke Power Co. v. Carolina
Environmental Study Group, Inc., 438 U. S. 59, 79. Pp. 12–17.
(b) The harms associated with climate change are serious and
well recognized. The Government’s own objective assessment of the
relevant science and a strong consensus among qualified experts in
dicate that global warming threatens, inter alia, a precipitate rise in
sea levels, severe and irreversible changes to natural ecosystems, a
significant reduction in winter snowpack with direct and important
economic consequences, and increases in the spread of disease and
the ferocity of weather events. That these changes are widely shared
does not minimize Massachusetts’ interest in the outcome of this liti
gation. See Federal Election Comm’n v. Akins, 524 U. S. 11, 24. Ac
cording to petitioners’ uncontested affidavits, global sea levels rose
between 10 and 20 centimeters over the 20th century as a result of
global warming and have already begun to swallow Massachusetts’
coastal land. Remediation costs alone, moreover, could reach hun
dreds of millions of dollars. Pp. 17–19.
(c) Given EPA’s failure to dispute the existence of a causal con
nection between man-made greenhouse gas emissions and global
warming, its refusal to regulate such emissions, at a minimum, “con
tributes” to Massachusetts’ injuries. EPA overstates its case in argu
ing that its decision not to regulate contributes so insignificantly to
petitioners’ injuries that it cannot be haled into federal court, and
that there is no realistic possibility that the relief sought would miti
gate global climate change and remedy petitioners’ injuries, espe
cially since predicted increases in emissions from China, India, and
other developing nations will likely offset any marginal domestic de
crease EPA regulation could bring about. Agencies, like legislatures,
do not generally resolve massive problems in one fell swoop, see Wil
liamson v. Lee Optical of Okla., Inc., 348 U. S. 483, 489, but instead
whittle away over time, refining their approach as circumstances
change and they develop a more nuanced understanding of how best
to proceed, cf. SEC v. Chenery Corp., 332 U. S. 194, 202–203. That a
4 MASSACHUSETTS v. EPA
Syllabus
first step might be tentative does not by itself negate federal-court ju
risdiction. And reducing domestic automobile emissions is hardly
tentative. Leaving aside the other greenhouse gases, the record indi
cates that the U. S. transportation sector emits an enormous quantity
of carbon dioxide into the atmosphere. Pp. 20–21.
(d) While regulating motor-vehicle emissions may not by itself
reverse global warming, it does not follow that the Court lacks juris
diction to decide whether EPA has a duty to take steps to slow or re
duce it. See Larson v. Valente, 456 U. S. 228, 243, n. 15. Because of
the enormous potential consequences, the fact that a remedy’s effec
tiveness might be delayed during the (relatively short) time it takes
for a new motor-vehicle fleet to replace an older one is essentially ir
relevant. Nor is it dispositive that developing countries are poised to
substantially increase greenhouse gas emissions: A reduction in do
mestic emissions would slow the pace of global emissions increases,
no matter what happens elsewhere. The Court attaches considerable
significance to EPA’s espoused belief that global climate change must
be addressed. Pp. 21–23.
2. The scope of the Court’s review of the merits of the statutory is
sues is narrow. Although an agency’s refusal to initiate enforcement
proceedings is not ordinarily subject to judicial review, Heckler v.
Chaney, 470 U. S. 821, there are key differences between nonen
forcement and denials of rulemaking petitions that are, as in the pre
sent circumstances, expressly authorized. EPA concluded alterna
tively in its petition denial that it lacked authority under §7521(a)(1)
to regulate new vehicle emissions because carbon dioxide is not an
“air pollutant” under §7602, and that, even if it possessed authority,
it would decline to exercise it because regulation would conflict with
other administration priorities. Because the Act expressly permits
review of such an action, §7607(b)(1), this Court “may reverse [it if it
finds it to be] arbitrary, capricious, an abuse of discretion, or other
wise not in accordance with law,” §7607(d)(9). Pp. 24–25.
3. Because greenhouse gases fit well within the Act’s capacious
definition of “air pollutant,” EPA has statutory authority to regulate
emission of such gases from new motor vehicles. That definition—
which includes “any air pollution agent . . . , including any physical,
chemical, . . . substance . . . emitted into . . . the ambient air . . . ,”
§7602(g) (emphasis added)—embraces all airborne compounds of
whatever stripe. Moreover, carbon dioxide and other greenhouse
gases are undoubtedly “physical [and] chemical . . . substance[s].”
Ibid. EPA’s reliance on postenactment congressional actions and de
liberations it views as tantamount to a command to refrain from
regulating greenhouse gas emissions is unavailing. Even if pos
tenactment legislative history could shed light on the meaning of an
Cite as: 549 U. S. ____ (2007) 5
Syllabus
otherwise-unambiguous statute, EPA identifies nothing suggesting
that Congress meant to curtail EPA’s power to treat greenhouse
gases as air pollutants. The Court has no difficulty reconciling Con
gress’ various efforts to promote interagency collaboration and re
search to better understand climate change with the agency’s pre
existing mandate to regulate “any air pollutant” that may endanger
the public welfare. FDA v. Brown & Williamson Tobacco Corp., 529
U. S. 120, 133, distinguished. Also unpersuasive is EPA’s argument
that its regulation of motor-vehicle carbon dioxide emissions would
require it to tighten mileage standards, a job (according to EPA) that
Congress has assigned to the Department of Transportation. The
fact that DOT’s mandate to promote energy efficiency by setting
mileage standards may overlap with EPA’s environmental responsi
bilities in no way licenses EPA to shirk its duty to protect the public
“health” and “welfare,” §7521(a)(1). Pp. 25–30.
4. EPA’s alternative basis for its decision—that even if it has statu
tory authority to regulate greenhouse gases, it would be unwise to do
so at this time—rests on reasoning divorced from the statutory text.
While the statute conditions EPA action on its formation of a “judg
ment,” that judgment must relate to whether an air pollutant
“cause[s], or contribute[s] to, air pollution which may reasonably be
anticipated to endanger public health or welfare.” §7601(a)(1). Under
the Act’s clear terms, EPA can avoid promulgating regulations 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. It has refused to do so, offering instead a laundry list of reasons
not to regulate, including the existence of voluntary Executive
Branch programs providing a response to global warming and im
pairment of the President’s ability to negotiate with developing na
tions to reduce emissions. These policy judgments have nothing to do
with whether greenhouse gas emissions contribute to climate change
and do not amount to a reasoned justification for declining to form a
scientific judgment. Nor can EPA avoid its statutory obligation by
noting the uncertainty surrounding various features of climate
change and concluding that it would therefore be better not to regu
late at this time. If the scientific uncertainty is so profound that it
precludes EPA from making a reasoned judgment, it must say so.
The statutory question is whether sufficient information exists for it
to make an endangerment finding. Instead, EPA rejected the rule-
making petition based on impermissible considerations. Its action
was therefore “arbitrary, capricious, or otherwise not in accordance
with law,” §7607(d)(9). On remand, EPA must ground its reasons for
action or inaction in the statute. Pp. 30–32.
6 MASSACHUSETTS v. EPA
Syllabus
415 F. 3d 50, reversed and remanded.
STEVENS, J., delivered the opinion of the Court, in which KENNEDY,
SOUTER, GINSBURG, and BREYER, JJ., joined. ROBERTS, C. J., filed a dis
senting opinion, in which SCALIA, THOMAS, and ALITO, JJ., joined.
SCALIA, J., filed a dissenting opinion, in which ROBERTS, C. J., and
THOMAS and ALITO, JJ., joined.
Cite as: 549 U. S. ____ (2007) 1
Opinion of the Court
NOTICE: This opinion is subject to formal revision before publication in the
preliminary print of the United States Reports. Readers are requested to
notify the Reporter of Decisions, Supreme Court of the United States, Wash
ington, D. C. 20543, of any typographical or other formal errors, in order
that corrections may be made before the preliminary print goes to press.
SUPREME COURT OF THE UNITED STATES
_________________
No. 05–1120
_________________
MASSACHUSETTS, ET AL., PETITIONERS v. ENVIRON
MENTAL PROTECTION AGENCY ET AL.
ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF
APPEALS FOR THE DISTRICT OF COLUMBIA CIRCUIT
[April 2, 2007]
JUSTICE STEVENS delivered the opinion of the Court.
A well-documented rise in global temperatures has
coincided with a significant increase in the concentration
of carbon dioxide in the atmosphere. Respected scientists
believe the two trends are related. For when carbon diox
ide is released into the atmosphere, it acts like the ceiling
of a greenhouse, trapping solar energy and retarding the
escape of reflected heat. It is therefore a species—the
most important species—of a “greenhouse gas.”
Calling global warming “the most pressing environ
mental challenge of our time,”1 a group of States,2 local
governments,3 and private organizations,4 alleged in a
——————
1 Pet. for Cert. 22.
2 California, Connecticut, Illinois, Maine, Massachusetts, New Jersey,
New Mexico, New York, Oregon, Rhode Island, Vermont, and Washington.
3 District of Columbia, American Samoa, New York City, and Baltimore.
4 Center for Biological Diversity, Center for Food Safety, Conserva
tion Law Foundation, Environmental Advocates, Environmental
Defense, Friends of the Earth, Greenpeace, International Center for
Technology Assessment, National Environmental Trust, Natural
Resources Defense Council, Sierra Club, Union of Concerned Scientists,
and U. S. Public Interest Research Group.
2 MASSACHUSETTS v. EPA
Opinion of the Court
petition for certiorari that the Environmental Protection
Agency (EPA) has abdicated its responsibility under the
Clean Air Act to regulate the emissions of four greenhouse
gases, including carbon dioxide. Specifically, petitioners
asked us to answer two questions concerning the meaning
of §202(a)(1) of the Act: whether EPA has the statutory
authority to regulate greenhouse gas emissions from new
motor vehicles; and if so, whether its stated reasons for
refusing to do so are consistent with the statute.
In response, EPA, supported by 10 intervening States5
and six trade associations,6 correctly argued that we may
not address those two questions unless at least one peti
tioner has standing to invoke our jurisdiction under Arti
cle III of the Constitution. Notwithstanding the serious
character of that jurisdictional argument and the absence
of any conflicting decisions construing §202(a)(1), the
unusual importance of the underlying issue persuaded us
to grant the writ. 548 U. S. __ (2006).
I
Section 202(a)(1) of the Clean Air Act, as added by Pub.
L. 89–272, §101(8), 79 Stat. 992, and as amended by, inter
alia, 84 Stat. 1690 and 91 Stat. 791, 42 U. S. C. §7521(a)(1),
provides:
“The [EPA] Administrator shall by regulation pre
scribe (and from time to time revise) in accordance
with the provisions of this section, standards applica
ble 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
——————
5 Alaska, Idaho, Kansas, Michigan, Nebraska, North Dakota, Ohio,
South Dakota, Texas, and Utah.
6 Alliance of Automobile Manufacturers, National Automobile Dealers
Association, Engine Manufacturers Association, Truck Manufacturers
Association, CO2 Litigation Group, and Utility Air Regulatory Group.
Cite as: 549 U. S. ____ (2007) 3
Opinion of the Court
to endanger public health or welfare . . . .”7
The Act defines “air pollutant” to include “any air pollu
tion agent or combination of such agents, including any
physical, chemical, biological, radioactive . . . substance or
matter which is emitted into or otherwise enters the am
bient air.” §7602(g). “Welfare” is also defined broadly:
among other things, it includes “effects on . . . weather . . .
and climate.” §7602(h).
When Congress enacted these provisions, the study of
climate change was in its infancy.8 In 1959, shortly after
the U. S. Weather Bureau began monitoring atmospheric
carbon dioxide levels, an observatory in Mauna Loa, Ha
waii, recorded a mean level of 316 parts per million. This
was well above the highest carbon dioxide concentration—
no more than 300 parts per million—revealed in the
420,000-year-old ice-core record.9 By the time Congress
——————
7 The 1970 version of §202(a)(1) used the phrase “which endangers
the public health or welfare” rather than the more-protective “which
may reasonably be anticipated to endanger public health or welfare.”
See §6(a) of the Clean Air Amendments of 1970, 84 Stat. 1690. Con
gress amended §202(a)(1) in 1977 to give its approval to the decision in
Ethyl Corp. v. EPA, 541 F. 2d 1, 25 (CADC 1976) (en banc), which held
that 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 §401(d)(1) of the Clean Air Act
Amendments of 1977, 91 Stat. 791; see also H. R. Rep. No. 95–294,
p. 49 (1977).
8 The Council on Environmental Quality had issued a report in 1970
concluding that “[m]an may be changing his weather.” Environmental
Quality: The First Annual Report 93. Considerable uncertainty remained
in those early years, and the issue went largely unmentioned in the
congressional debate over the enactment of the Clean Air Act. But see
116 Cong. Rec. 32914 (1970) (statement of Sen. Boggs referring to
Council’s conclusion that “[a]ir pollution alters the climate and may
produce global changes in temperature”).
9 See Intergovernmental Panel on Climate Change, Climate Change
2001: Synthesis Report, pp. 202–203 (2001). By drilling through thick
Antarctic ice sheets and extracting “cores,” scientists can examine ice
4 MASSACHUSETTS v. EPA
Opinion of the Court
drafted §202(a)(1) in 1970, carbon dioxide levels had
reached 325 parts per million.10
In the late 1970’s, the Federal Government began devot
ing serious attention to the possibility that carbon dioxide
emissions associated with human activity could provoke
climate change. In 1978, Congress enacted the National
Climate Program Act, 92 Stat. 601, which required the
President to establish a program to “assist the Nation and
the world to understand and respond to natural and man-
induced climate processes and their implications,” id., §3.
President Carter, in turn, asked the National Research
Council, the working arm of the National Academy of
Sciences, to investigate the subject. The Council’s re
sponse was unequivocal: “If carbon dioxide continues to
increase, the study group finds no reason to doubt that
climate changes will result and no reason to believe that
these changes will be negligible. . . . A wait-and-see policy
may mean waiting until it is too late.”11
Congress next addressed the issue in 1987, when it
enacted the Global Climate Protection Act, Title XI of Pub.
L. 100–204, 101 Stat. 1407, note following 15 U. S. C.
§2901. Finding that “manmade pollution—the release of
carbon dioxide, chlorofluorocarbons, methane, and other
trace gases into the atmosphere—may be producing a
——————
from long ago and extract small samples of ancient air. That air can
then be analyzed, yielding estimates of carbon dioxide levels. Ibid.
10 A more dramatic rise was yet to come: In 2006, carbon dioxide lev
els reached 382 parts per million, see Dept. of Commerce, National
Oceanic & Atmospheric Administration, Mauna Loa CO2 Monthly Mean
Data, www.esrl.noaa.gov/gmd/ccgg/trends/co2_mm_mlo.dat (all Internet
materials as visited Mar. 29, 2007, and available in Clerk of Court’s
case file), a level thought to exceed the concentration of carbon dioxide
in the atmosphere at any point over the past 20-million years. See
Intergovernmental Panel on Climate Change, Technical Summary of
Working Group I Report 39 (2001).
11 Climate Research Board, Carbon Dioxide and Climate: A Scientific
Assessment, p. vii (1979).
Cite as: 549 U. S. ____ (2007) 5
Opinion of the Court
long-term and substantial increase in the average tem
perature on Earth,” §1102(1), 101 Stat. 1408, Congress
directed EPA to propose to Congress a “coordinated na
tional policy on global climate change,” §1103(b), and
ordered the Secretary of State to work “through the chan
nels of multilateral diplomacy” and coordinate diplomatic
efforts to combat global warming, §1103(c). Congress
emphasized that “ongoing pollution and deforestation may
be contributing now to an irreversible process” and that
“[n]ecessary actions must be identified and implemented
in time to protect the climate.” §1102(4).
Meanwhile, the scientific understanding of climate
change progressed. In 1990, the Intergovernmental Panel
on Climate Change (IPCC), a multinational scientific body
organized under the auspices of the United Nations, pub
lished its first comprehensive report on the topic. Draw
ing on expert opinions from across the globe, the IPCC
concluded that “emissions resulting from human activities
are substantially increasing the atmospheric concentra
tions of . . . greenhouse gases [which] will enhance the
greenhouse effect, resulting on average in an additional
warming of the Earth’s surface.”12
Responding to the IPCC report, the United Nations
convened the “Earth Summit” in 1992 in Rio de Janeiro.
The first President Bush attended and signed the United
Nations Framework Convention on Climate Change
(UNFCCC), a nonbinding agreement among 154 nations to
reduce atmospheric concentrations of carbon dioxide and
other greenhouse gases for the purpose of “prevent[ing]
dangerous anthropogenic [i.e., human-induced] interfer
ence with the [Earth’s] climate system.”13 S. Treaty Doc.
——————
12 IPCC, Climate Change: The IPCC Scientific Assessment, p. xi (J.
Houghton, G. Jenkins, & J. Ephraums eds. 1991).
13 The industrialized countries listed in Annex I to the UNFCCC un
dertook to reduce their emissions of greenhouse gases to 1990 levels by
the year 2000. No immediate restrictions were imposed on developing
6 MASSACHUSETTS v. EPA
Opinion of the Court
No. 102–38, Art. 2, p. 5 (1992). The Senate unanimously
ratified the treaty.
Some five years later—after the IPCC issued a second
comprehensive report in 1995 concluding that “[t]he bal
ance of evidence suggests there is a discernible human
influence on global climate”14—the UNFCCC signatories
met in Kyoto, Japan, and adopted a protocol that assigned
mandatory targets for industrialized nations to reduce
greenhouse gas emissions. Because those targets did not
apply to developing and heavily polluting nations such as
China and India, the Senate unanimously passed a resolu
tion expressing its sense that the United States should not
enter into the Kyoto Protocol. See S. Res. 98, 105th Cong.,
1st Sess. (July 25, 1997) (as passed). President Clinton did
not submit the protocol to the Senate for ratification.
II
On October 20, 1999, a group of 19 private organiza
tions15 filed a rulemaking petition asking EPA to regulate
“greenhouse gas emissions from new motor vehicles under
§202 of the Clean Air Act.” App. 5. Petitioners main
tained that 1998 was the “warmest year on record”; that
carbon dioxide, methane, nitrous oxide, and hydrofluoro
carbons are “heat trapping greenhouse gases”; that green
——————
countries, including China and India. They could choose to become
Annex I countries when sufficiently developed.
14 IPCC, Climate Change 1995, The Science of Climate Change, p. 4.
15 Alliance for Sustainable Communities; Applied Power Technologies,
Inc.; Bio Fuels America; The California Solar Energy Industries Assn.;
Clements Environmental Corp.; Environmental Advocates; Environ
mental and Energy Study Institute; Friends of the Earth; Full Circle
Energy Project, Inc.; The Green Party of Rhode Island; Greenpeace
USA; International Center for Technology Assessment; Network for
Environmental and Economic Responsibility of the United Church of
Christ; New Jersey Environmental Watch; New Mexico Solar Energy
Assn.; Oregon Environmental Council; Public Citizen; Solar Energy
Industries Assn.; The SUN DAY Campaign. See App. 7–11.
Cite as: 549 U. S. ____ (2007) 7
Opinion of the Court
house gas emissions have significantly accelerated climate
change; and that the IPCC’s 1995 report warned that
“carbon dioxide remains the most important contributor to
[man-made] forcing of climate change.” Id., at 13 (internal
quotation marks omitted). The petition further alleged
that climate change will have serious adverse effects on
human health and the environment. Id., at 22–35. As to
EPA’s statutory authority, the petition observed that the
agency itself had already confirmed that it had the power
to regulate carbon dioxide. See id., at 18, n. 21. In 1998,
Jonathan Z. Cannon, then EPA’s General Counsel, pre
pared a legal opinion concluding that “CO2 emissions are
within the scope of EPA’s authority to regulate,” even as
he recognized that EPA had so far declined to exercise
that authority. Id., at 54 (memorandum to Carol M.
Browner, Administrator (Apr. 10, 1998) (hereinafter Can
non memorandum)). Cannon’s successor, Gary S. Guzy,
reiterated that opinion before a congressional committee
just two weeks before the rulemaking petition was filed.
See id., at 61.
Fifteen months after the petition’s submission, EPA
requested public comment on “all the issues raised in [the]
petition,” adding a “particular” request for comments on
“any scientific, technical, legal, economic or other aspect of
these issues that may be relevant to EPA’s consideration
of this petition.” 66 Fed. Reg. 7486, 7487 (2001). EPA
received more than 50,000 comments over the next five
months. See 68 Fed. Reg. 52924 (2003).
Before the close of the comment period, the White House
sought “assistance in identifying the areas in the science
of climate change where there are the greatest certainties
and uncertainties” from the National Research Council,
asking for a response “as soon as possible.” App. 213. The
result was a 2001 report titled Climate Change: An Analysis
of Some Key Questions (NRC Report), which, drawing heav
ily on the 1995 IPCC report, concluded that “[g]reenhouse
8 MASSACHUSETTS v. EPA
Opinion of the Court
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.” NRC Report 1.
On September 8, 2003, EPA entered an order denying the
rulemaking petition. 68 Fed. Reg. 52922. The agency gave
two reasons for its decision: (1) that contrary to the opin
ions of its former general counsels, the Clean Air Act does
not authorize EPA to issue mandatory regulations to
address global climate change, see id., at 52925–52929;
and (2) that even if the agency had the authority to set
greenhouse gas emission standards, it would be unwise to
do so at this time, id., at 52929–52931.
In concluding that it lacked statutory authority over
greenhouse gases, EPA observed that Congress “was well
aware of the global climate change issue when it last
comprehensively amended the [Clean Air Act] in 1990,”
yet it declined to adopt a proposed amendment establish
ing binding emissions limitations. Id., at 52926. Congress
instead chose to authorize further investigation into cli
mate change. Ibid. (citing §§103(g) and 602(e) of the
Clean Air Act Amendments of 1990, 104 Stat. 2652, 2703,
42 U. S. C. §§7403(g)(1) and 7671a(e)). EPA further rea
soned that Congress’ “specially tailored solutions to global
atmospheric issues,” 68 Fed. Reg. 52926—in particular, its
1990 enactment of a comprehensive scheme to regulate
pollutants that depleted the ozone layer, see Title VI, 104
Stat. 2649, 42 U. S. C. §§7671–7671q—counseled against
reading the general authorization of §202(a)(1) to confer
regulatory authority over greenhouse gases.
EPA stated that it was “urged on in this view” by this
Court’s decision in FDA v. Brown & Williamson Tobacco
Corp., 529 U. S. 120 (2000). In that case, relying on “to
bacco[’s] unique political history,” id., at 159, we invali
dated the Food and Drug Administration’s reliance on its
general authority to regulate drugs as a basis for asserting
Cite as: 549 U. S. ____ (2007) 9
Opinion of the Court
jurisdiction over an “industry constituting a significant
portion of the American economy,” ibid.
EPA reasoned that climate change had its own “political
history”: Congress designed the original Clean Air Act to
address local air pollutants rather than a substance that
“is fairly consistent in its concentration throughout the
world’s atmosphere,” 68 Fed. Reg. 52927 (emphasis
added); declined in 1990 to enact proposed amendments to
force EPA to set carbon dioxide emission standards for
motor vehicles, ibid. (citing H. R. 5966, 101st Cong., 2d
Sess. (1990)); and addressed global climate change in
other legislation, 68 Fed. Reg. 52927. Because of this
political history, and because imposing emission limita
tions on greenhouse gases would have even greater eco
nomic and political repercussions than regulating tobacco,
EPA was persuaded that it lacked the power to do so. Id.,
at 52928. In essence, EPA concluded that climate change
was so important that unless Congress spoke with exact
ing specificity, it could not have meant the agency to
address it.
Having reached that conclusion, EPA believed it fol
lowed that greenhouse gases cannot be “air pollutants”
within the meaning of the Act. See ibid. (“It follows from
this conclusion, that [greenhouse gases], as such, are not
air pollutants under the [Clean Air Act’s] regulatory pro
visions . . .”). The agency bolstered this conclusion by
explaining that if carbon dioxide were an air pollutant, the
only feasible method of reducing tailpipe emissions would
be to improve fuel economy. But because Congress has
already created detailed mandatory fuel economy stan
dards subject to Department of Transportation (DOT)
administration, the agency concluded that EPA regulation
would either conflict with those standards or be superflu
ous. Id., at 52929.
Even assuming that it had authority over greenhouse
gases, EPA explained in detail why it would refuse to exer
10 MASSACHUSETTS v. EPA
Opinion of the Court
cise that authority. The agency began by recognizing that
the concentration of greenhouse gases has dramatically
increased as a result of human activities, and acknowledged
the attendant increase in global surface air temperatures.
Id., at 52930. EPA nevertheless gave controlling impor
tance to the NRC Report’s statement that a causal link
between the two “ ‘cannot be unequivocally established.’ ”
Ibid. (quoting NRC Report 17). Given that residual uncer
tainty, EPA concluded that regulating greenhouse gas
emissions would be unwise. 68 Fed. Reg. 52930.
The agency furthermore characterized any EPA regula
tion of motor-vehicle emissions as a “piecemeal approach” to
climate change, id., at 52931, and stated that such regula
tion would conflict with the President’s “comprehensive
approach” to the problem, id., at 52932. That approach
involves additional support for technological innovation, the
creation of nonregulatory programs to encourage voluntary
private-sector reductions in greenhouse gas emissions, and
further research on climate change—not actual regulation.
Id., at 52932–52933. According to EPA, unilateral EPA
regulation of motor-vehicle greenhouse gas emissions might
also hamper the President’s ability to persuade key devel
oping countries to reduce greenhouse gas emissions. Id., at
52931.
III
Petitioners, now joined by intervenor States and local
governments, sought review of EPA’s order in the United
States Court of Appeals for the District of Columbia Cir
cuit.16 Although each of the three judges on the panel
wrote a separate opinion, two judges agreed “that the EPA
——————
16 See 42 U. S. C. §7607(b)(1) (“A petition for review of action of the
Administrator in promulgating any . . . standard under section 7521 of
this title . . . or final action taken, by the Administrator under this
chapter may be filed only in the United States Court of Appeals for the
District of Columbia”).
Cite as: 549 U. S. ____ (2007) 11
Opinion of the Court
Administrator properly exercised his discretion under
§202(a)(1) in denying the petition for rule making.” 415 F.
3d 50, 58 (2005). The court therefore denied the petition
for review.
In his opinion announcing the court’s judgment, Judge
Randolph avoided a definitive ruling as to petitioners’
standing, id., at 56, reasoning that it was permissible to
proceed to the merits because the standing and the merits
inquiries “overlap[ped],” ibid. Assuming without deciding
that the statute authorized the EPA Administrator to
regulate greenhouse gas emissions that “in his judgment”
may “reasonably be anticipated to endanger public health
or welfare,” 42 U. S. C. §7521(a)(1), Judge Randolph con
cluded that the exercise of that judgment need not be
based solely on scientific evidence, but may also be in
formed by the sort of policy judgments that motivate
congressional action. 415 F. 3d, at 58. Given that frame
work, it was reasonable for EPA to base its decision on
scientific uncertainty as well as on other factors, including
the concern that unilateral regulation of U. S. motor-
vehicle emissions could weaken efforts to reduce green
house gas emissions from other countries. Ibid.
Judge Sentelle wrote separately because he believed
petitioners failed to “demonstrat[e] the element of injury
necessary to establish standing under Article III.” Id., at
59 (opinion dissenting in part and concurring in judg
ment). In his view, they had alleged that global warming
is “harmful to humanity at large,” but could not allege
“particularized injuries” to themselves. Id., at 60 (citing
Lujan v. Defenders of Wildlife, 504 U. S. 555, 562 (1992)).
While he dissented on standing, however, he accepted the
contrary view as the law of the case and joined Judge
Randolph’s judgment on the merits as the closest to that
which he preferred. 415 F. 3d, at 60–61.
Judge Tatel dissented. Emphasizing that EPA nowhere
challenged the factual basis of petitioners’ affidavits, id.,
12 MASSACHUSETTS v. EPA
Opinion of the Court
at 66, he concluded that at least Massachusetts had “satis
fied each element of Article III standing—injury, causa
tion, and redressability,” id., at 64. In Judge Tatel’s view,
the “ ‘substantial probability,’ ” id., at 66, that projected
rises in sea level would lead to serious loss of coastal
property was a “far cry” from the kind of generalized harm
insufficient to ground Article III jurisdiction. Id., at 65.
He found that petitioners’ affidavits more than adequately
supported the conclusion that EPA’s failure to curb green
house gas emissions contributed to the sea level changes
that threatened Massachusetts’ coastal property. Ibid. As
to redressability, he observed that one of petitioners’
experts, a former EPA climatologist, stated that
“ ‘[a]chievable reductions in emissions of CO2 and other
[greenhouse gases] from U. S. motor vehicles would . . .
delay and moderate many of the adverse impacts of global
warming.’ ” Ibid. (quoting declaration of Michael Mac-
Cracken, former Executive Director, U. S. Global Change
Research Program ¶5(e) (hereinafter MacCracken Decl.),
available in 2 Petitioners’ Standing Appendix in No. 03–
1361, etc., (CADC), p. 209 (Stdg. App.)). He further noted
that the one-time director of EPA’s motor-vehicle pollution
control efforts stated in an affidavit that enforceable emis
sion standards would lead to the development of new
technologies that “ ‘would gradually be mandated by other
countries around the world.’ ” 415 F. 3d, at 66 (quoting
declaration of Michael Walsh ¶¶7–8, 10, Stdg. App. 309–
310, 311). On the merits, Judge Tatel explained at length
why he believed the text of the statute provided EPA with
authority to regulate greenhouse gas emissions, and why
its policy concerns did not justify its refusal to exercise
that authority. 415 F. 3d, at 67–82.
IV
Article III of the Constitution limits federal-court juris
diction to “Cases” and “Controversies.” Those two words
Cite as: 549 U. S. ____ (2007) 13
Opinion of the Court
confine “the business of federal courts to questions pre
sented in an adversary context and in a form historically
viewed as capable of resolution through the judicial proc
ess.” Flast v. Cohen, 392 U. S. 83, 95 (1968). It is there
fore familiar learning that no justiciable “controversy”
exists when parties seek adjudication of a political ques
tion, Luther v. Borden, 7 How. 1 (1849), when they ask for
an advisory opinion, Hayburn’s Case, 2 Dall. 409 (1792),
see also Clinton v. Jones, 520 U. S. 681, 700, n. 33 (1997),
or when the question sought to be adjudicated has been
mooted by subsequent developments, California v. San
Pablo & Tulare R. Co., 149 U. S. 308 (1893). This case
suffers from none of these defects.
The parties’ dispute turns on the proper construction of a
congressional statute, a question eminently suitable to
resolution in federal court. Congress has moreover author
ized this type of challenge to EPA action. See 42 U. S. C.
§7607(b)(1). That authorization is of critical importance to
the standing inquiry: “Congress has the power to define
injuries and articulate chains of causation that will give
rise to a case or controversy where none existed before.”
Lujan, 504 U. S., at 580 (KENNEDY, J., concurring in part
and concurring in judgment). “In exercising this power,
however, Congress must at the very least identify the
injury it seeks to vindicate and relate the injury to the
class of persons entitled to bring suit.” Ibid. We will not,
therefore, “entertain citizen suits to vindicate the public’s
nonconcrete interest in the proper administration of the
laws.” Id., at 581.
EPA maintains that because greenhouse gas emissions
inflict widespread harm, the doctrine of standing presents
an insuperable jurisdictional obstacle. We do not agree.
At bottom, “the gist of the question of standing” is whether
petitioners have “such a personal stake in the outcome of
the controversy as to assure that concrete adverseness
which sharpens the presentation of issues upon which the
14 MASSACHUSETTS v. EPA
Opinion of the Court
court so largely depends for illumination.” Baker v. Carr,
369 U. S. 186, 204 (1962). As JUSTICE KENNEDY explained
in his Lujan concurrence:
“While it does not matter how many persons have
been injured by the challenged action, the party bring
ing suit must show that the action injures him in a
concrete and personal way. This requirement is not
just an empty formality. It preserves the vitality of
the adversarial process by assuring both that the par
ties before the court have an actual, as opposed to pro
fessed, stake in the outcome, and that the legal ques
tions presented . . . will be resolved, not in the rarified
atmosphere of a debating society, but in a concrete
factual context conducive to a realistic appreciation of
the consequences of judicial action.” 504 U. S., at 581
(internal quotation marks omitted).
To ensure the proper adversarial presentation, Lujan
holds that a litigant must demonstrate that it has suffered
a concrete and particularized injury that is either actual
or imminent, that the injury is fairly traceable to the
defendant, and that it is likely that a favorable decision
will redress that injury. See id., at 560–561. However, a
litigant to whom Congress has “accorded a procedural
right to protect his concrete interests,” id., at 572, n. 7—
here, the right to challenge agency action unlawfully
withheld, §7607(b)(1)—“can assert that right without
meeting all the normal standards for redressability and
immediacy,” ibid. When a litigant is vested with a proce
dural right, that litigant has standing if there is some
possibility that the requested relief will prompt the injury-
causing party to reconsider the decision that allegedly
harmed the litigant. Ibid.; see also Sugar Cane Growers
Cooperative of Fla. v. Veneman, 289 F. 3d 89, 94–95
(CADC 2002) (“A [litigant] who alleges a deprivation of a
procedural protection to which he is entitled never has to
Cite as: 549 U. S. ____ (2007) 15
Opinion of the Court
prove that if he had received the procedure the substan
tive result would have been altered. All that is necessary
is to show that the procedural step was connected to the
substantive result”).
Only one of the petitioners needs to have standing to
permit us to consider the petition for review. See Rumsfeld
v. Forum for Academic and Institutional Rights, Inc., 547
U. S. 47, 52, n. 2 (2006). We stress here, as did Judge Tatel
below, the special position and interest of Massachusetts.
It is of considerable relevance that the party seeking re
view here is a sovereign State and not, as it was in Lujan,
a private individual.
Well before the creation of the modern administrative
state, we recognized that States are not normal litigants
for the purposes of invoking federal jurisdiction. As Jus
tice Holmes explained in Georgia v. Tennessee Copper Co.,
206 U. S. 230, 237 (1907), a case in which Georgia sought
to protect its citizens from air pollution originating outside
its borders:
“The case has been argued largely as if it were one
between two private parties; but it is not. The very
elements that would be relied upon in a suit between
fellow-citizens as a ground for equitable relief are
wanting here. The State owns very little of the terri
tory alleged to be affected, and the damage to it capa
ble of estimate in money, possibly, at least, is small.
This is a suit by a State for an injury to it in its capac
ity of quasi-sovereign. In that capacity the State has
an interest independent of and behind the titles of its
citizens, in all the earth and air within its domain. It
has the last word as to whether its mountains shall be
stripped of their forests and its inhabitants shall
breathe pure air.”
Just as Georgia’s “independent interest . . . in all the earth
and air within its domain” supported federal jurisdiction a
16 MASSACHUSETTS v. EPA
Opinion of the Court
century ago, so too does Massachusetts’ well-founded
desire to preserve its sovereign territory today. Cf. Alden
v. Maine, 527 U. S. 706, 715 (1999) (observing that in the
federal system, the States “are not relegated to the role of
mere provinces or political corporations, but retain the
dignity, though not the full authority, of sovereignty”).
That Massachusetts does in fact own a great deal of the
“territory alleged to be affected” only reinforces the con
clusion that its stake in the outcome of this case is suffi
ciently concrete to warrant the exercise of federal judicial
power.
When a State enters the Union, it surrenders certain
sovereign prerogatives. Massachusetts cannot invade
Rhode Island to force reductions in greenhouse gas emis
sions, it cannot negotiate an emissions treaty with China
or India, and in some circumstances the exercise of its
police powers to reduce in-state motor-vehicle emissions
might well be pre-empted. See Alfred L. Snapp & Son,
Inc. v. Puerto Rico ex rel. Barez, 458 U. S. 592, 607 (1982)
(“One helpful indication in determining whether an al
leged injury to the health and welfare of its citizens suf
fices to give the State standing to sue parens patriae is
whether the injury is one that the State, if it could, would
likely attempt to address through its sovereign lawmaking
powers”).
These sovereign prerogatives are now lodged in the
Federal Government, and Congress has ordered EPA to
protect Massachusetts (among others) by prescribing stan
dards applicable to the “emission of any air pollutant from
any class or classes of new motor vehicle engines, which in
[the Administrator’s] judgment cause, or contribute to, air
pollution which may reasonably be anticipated to endanger
public health or welfare.” 42 U. S. C. §7521(a)(1). Con
gress has moreover recognized a concomitant procedural
right to challenge the rejection of its rulemaking petition
as arbitrary and capricious. §7607(b)(1). Given that pro
Cite as: 549 U. S. ____ (2007) 17
Opinion of the Court
cedural right and Massachusetts’ stake in protecting its
quasi-sovereign interests, the Commonwealth is entitled to
special solicitude in our standing analysis.17
——————
17 THE CHIEF JUSTICE accuses the Court of misreading Georgia v. Ten
nessee Copper Co., 206 U. S. 230 (1907), see post, at 3–4 (dissenting
opinion), and “devis[ing] a new doctrine of state standing,” id., at 15.
But no less an authority than Hart & Wechsler’s The Federal Courts
and the Federal System understands Tennessee Copper as a standing
decision. R. Fallon, D. Meltzer, & D. Shapiro, Hart & Wechsler’s The
Federal Courts and the Federal System 290 (5th ed. 2003). Indeed, it
devotes an entire section to chronicling the long development of cases
permitting States “to litigate as parens patriae to protect quasi-
sovereign interests—i.e., public or governmental interests that concern
the state as a whole.” Id., at 289; see, e.g., Missouri v. Illinois, 180
U. S. 208, 240–241 (1901) (finding federal jurisdiction appropriate not
only “in cases involving boundaries and jurisdiction over lands and
their inhabitants, and in cases directly affecting the property rights
and interests of a state,” but also when the “substantial impairment of
the health and prosperity of the towns and cities of the state” are at
stake).
Drawing on Massachusetts v. Mellon, 262 U. S. 447 (1923), and Alfred
L. Snapp & Son, Inc. v. Puerto Rico ex rel. Barez, 458 U. S. 592 (1982)
(citing Missouri v. Illinois, 180 U. S. 208 (1901)), THE CHIEF JUSTICE
claims that we “overloo[k] the fact that our cases cast significant doubt
on a State’s standing to assert a quasi-sovereign interest . . . against
the Federal Government.” Post, at 5. Not so. Mellon itself disavowed
any such broad reading when it noted that the Court had been “called
upon to adjudicate, not rights of person or property, not rights of
dominion over physical domain, [and] not quasi sovereign rights actu
ally invaded or threatened.” 262 U. S., at 484–485 (emphasis added).
In any event, we held in Georgia v. Pennsylvania R. Co., 324 U. S. 439,
447 (1945), that there is a critical difference between allowing a State
“to protect her citizens from the operation of federal statutes” (which is
what Mellon prohibits) and allowing a State to assert its rights under
federal law (which it has standing to do). Massachusetts does not here
dispute that the Clean Air Act applies to its citizens; it rather seeks to
assert its rights under the Act. See also Nebraska v. Wyoming, 515
U. S. 1, 20 (1995) (holding that Wyoming had standing to bring a cross-
claim against the United States to vindicate its “ ‘quasi-sovereign’
interests which are ‘independent of and behind the titles of its citizens,
in all the earth and air within its domain’ ” (quoting Tennessee Copper,
206 U. S., at 237)).
18 MASSACHUSETTS v. EPA
Opinion of the Court
With that in mind, it is clear that petitioners’ submis
sions as they pertain to Massachusetts have satisfied the
most demanding standards of the adversarial process.
EPA’s steadfast refusal to regulate greenhouse gas emis
sions presents a risk of harm to Massachusetts that is
both “actual” and “imminent.” Lujan, 504 U. S., at 560
(internal quotation marks omitted). There is, moreover, a
“substantial likelihood that the judicial relief requested”
will prompt EPA to take steps to reduce that risk. Duke
Power Co. v. Carolina Environmental Study Group, Inc.,
438 U. S. 59, 79 (1978).
The Injury
The harms associated with climate change are serious
and well recognized. Indeed, the NRC Report itself—
which EPA regards as an “objective and independent
assessment of the relevant science,” 68 Fed. Reg. 52930—
identifies a number of environmental changes that have
already inflicted significant harms, including “the global
retreat of mountain glaciers, reduction in snow-cover
extent, the earlier spring melting of rivers and lakes, [and]
the accelerated rate of rise of sea levels during the 20th
century relative to the past few thousand years . . . .”
NRC Report 16.
Petitioners allege that this only hints at the environ
mental damage yet to come. According to the climate
scientist Michael MacCracken, “qualified scientific experts
involved in climate change research” have reached a
“strong consensus” that global warming threatens (among
other things) a precipitate rise in sea levels by the end of
the century, MacCracken Decl. ¶15, Stdg. App. 207, “se
vere and irreversible changes to natural ecosystems,” id.,
¶5(d), at 209, a “significant reduction in water storage in
winter snowpack in mountainous regions with direct and
important economic consequences,” ibid., and an increase
in the spread of disease, id., ¶28, at 218–219. He also
Cite as: 549 U. S. ____ (2007) 19
Opinion of the Court
observes that rising ocean temperatures may contribute to
the ferocity of hurricanes. Id., ¶¶23–25, at 216–217.18
That these climate-change risks are “widely shared”
does not minimize Massachusetts’ interest in the outcome
of this litigation. See Federal Election Comm’n v. Akins,
524 U. S. 11, 24 (1998) (“[W]here a harm is concrete,
though widely shared, the Court has found ‘injury in
fact’ ”). According to petitioners’ unchallenged affidavits,
global sea levels rose somewhere between 10 and 20 cen
timeters over the 20th century as a result of global warm
ing. MacCracken Decl. ¶5(c), Stdg. App. 208. These rising
seas have already begun to swallow Massachusetts’
coastal land. Id., at 196 (declaration of Paul H. Kirshen
¶5), 216 (MacCracken Decl. ¶23). Because the Common
wealth “owns a substantial portion of the state’s coastal
property,” id., at 171 (declaration of Karst R. Hoogeboom
¶4),19 it has alleged a particularized injury in its capacity
——————
18 In this regard, MacCracken’s 2004 affidavit—drafted more than a
year in advance of Hurricane Katrina—was eerily prescient. Immedi
ately after discussing the “particular concern” that climate change
might cause an “increase in the wind speed and peak rate of precipita
tion of major tropical cyclones (i.e., hurricanes and typhoons),” Mac-
Cracken noted that “[s]oil compaction, sea level rise and recurrent
storms are destroying approximately 20–30 square miles of Louisiana
wetlands each year. These wetlands serve as a ‘shock absorber’ for
storm surges that could inundate New Orleans, significantly enhancing
the risk to a major urban population.” ¶¶24–25, Stdg. App. 217.
19 “For example, the [Massachusetts Department of Conservation and
Recreation] owns, operates and maintains approximately 53 coastal
state parks, beaches, reservations, and wildlife sanctuaries. [It] also
owns, operates and maintains sporting and recreational facilities in
coastal areas, including numerous pools, skating rinks, playgrounds,
playing fields, former coastal fortifications, public stages, museums,
bike trails, tennis courts, boathouses and boat ramps and landings.
Associated with these coastal properties and facilities is a significant
amount of infrastructure, which the Commonwealth also owns, oper
ates and maintains, including roads, parkways, stormwater pump
stations, pier[s], sea wal[l] revetments and dams.” Hoogeboom Decl.
¶4, at 171.
20 MASSACHUSETTS v. EPA
Opinion of the Court
as a landowner. The severity of that injury will only
increase over the course of the next century: If sea levels
continue to rise as predicted, one Massachusetts official
believes that a significant fraction of coastal property will
be “either permanently lost through inundation or temporar
ily lost through periodic storm surge and flooding events.”
Id., ¶6, at 172.20 Remediation costs alone, petitioners allege,
could run well into the hundreds of millions of dollars. Id.,
¶7, at 172; see also Kirshen Decl. ¶12, at 198.21
Causation
EPA does not dispute the existence of a causal connec
tion between man-made greenhouse gas emissions and
global warming. At a minimum, therefore, EPA’s refusal
to regulate such emissions “contributes” to Massachusetts’
injuries.
EPA nevertheless maintains that its decision not to
regulate greenhouse gas emissions from new motor vehi
cles contributes so insignificantly to petitioners’ injuries
that the agency cannot be haled into federal court to an
swer for them. For the same reason, EPA does not believe
——————
20 See also id., at 179 (declaration of Christian Jacqz) (discussing
possible loss of roughly 14 acres of land per miles of coastline by 2100);
Kirshen Decl. ¶10, at 198 (alleging that “[w]hen such a rise in sea level
occurs, a 10-year flood will have the magnitude of the present 100-year
flood and a 100-year flood will have the magnitude of the present 500
year flood”).
21 In dissent, THE CHIEF JUSTICE dismisses petitioners’ submissions as
“conclusory,” presumably because they do not quantify Massachusetts’
land loss with the exactitude he would prefer. Post, at 8. He therefore
asserts that the Commonwealth’s injury is “conjectur[al].” See ibid.
Yet the likelihood that Massachusetts’ coastline will recede has nothing
to do with whether petitioners have determined the precise metes and
bounds of their soon-to-be-flooded land. Petitioners maintain that the
seas are rising and will continue to rise, and have alleged that such a
rise will lead to the loss of Massachusetts’ sovereign territory. No one,
save perhaps the dissenters, disputes those allegations. Our cases
require nothing more.
Cite as: 549 U. S. ____ (2007) 21
Opinion of the Court
that any realistic possibility exists that the relief petition
ers seek would mitigate global climate change and remedy
their injuries. That is especially so because predicted
increases in greenhouse gas emissions from developing
nations, particularly China and India, are likely to offset
any marginal domestic decrease.
But EPA overstates its case. Its argument rests on the
erroneous assumption that a small incremental step,
because it is incremental, can never be attacked in a fed
eral judicial forum. Yet accepting that premise would
doom most challenges to regulatory action. Agencies, like
legislatures, do not generally resolve massive problems in
one fell regulatory swoop. See Williamson v. Lee Optical
of Okla., Inc., 348 U. S. 483, 489 (1955) (“[A] reform may
take one step at a time, addressing itself to the phase of
the problem which seems most acute to the legislative
mind”). They instead whittle away at them over time,
refining their preferred approach as circumstances change
and as they develop a more-nuanced understanding of how
best to proceed. Cf. SEC v. Chenery Corp., 332 U. S. 194,
202 (1947) (“Some principles must await their own devel
opment, while others must be adjusted to meet particular,
unforeseeable situations”). That a first step might be
tentative does not by itself support the notion that federal
courts lack jurisdiction to determine whether that step
conforms to law.
And reducing domestic automobile emissions is hardly a
tentative step. Even leaving aside the other greenhouse
gases, the United States transportation sector emits an
enormous quantity of carbon dioxide into the atmos
phere—according to the MacCracken affidavit, more than
1.7 billion metric tons in 1999 alone. ¶30, Stdg. App. 219.
That accounts for more than 6% of worldwide carbon
dioxide emissions. Id., at 232 (Oppenheimer Decl. ¶3); see
also MacCracken Decl. ¶31, at 220. To put this in per
spective: Considering just emissions from the transporta
22 MASSACHUSETTS v. EPA
Opinion of the Court
tion sector, which represent less than one-third of this
country’s total carbon dioxide emissions, the United States
would still rank as the third-largest emitter of carbon
dioxide in the world, outpaced only by the European Union
and China.22 Judged by any standard, U. S. motor-vehicle
emissions make a meaningful contribution to greenhouse
gas concentrations and hence, according to petitioners, to
global warming.
The Remedy
While it may be true that regulating motor-vehicle
emissions will not by itself reverse global warming, it by no
means follows that we lack jurisdiction to decide whether
EPA has a duty to take steps to slow or reduce it. See also
Larson v. Valente, 456 U. S. 228, 244, n. 15 (1982) (“[A]
plaintiff satisfies the redressability requirement when he
shows that a favorable decision will relieve a discrete
injury to himself. He need not show that a favorable
decision will relieve his every injury”). Because of the
enormity of the potential consequences associated with
man-made climate change, the fact that the effectiveness
of a remedy might be delayed during the (relatively short)
time it takes for a new motor-vehicle fleet to replace an
older one is essentially irrelevant.23 Nor is it dispositive
——————
22 See UNFCCC, National Greenhouse Gas Inventory Data for the Period
1990–2004 and Status of Reporting 14 (2006) (hereinafter Inventory Data)
(reflecting emissions from Annex I countries); UNFCCC, Sixth Compilation
and Synthesis of Initial National Communications from Parties not In
cluded in Annex I to the Convention 7–8 (2005) (reflecting emissions from
non-Annex I countries); see also Dept. of Energy, Energy Information
Admin., International Energy Annual 2004, H.1co2 World Carbon Dioxide
Emissions from the Consumption and Flaring of Fossil Fuels, 1980–2004
(Table), http://www.eia.doe.gov/pub/international/iealf/tableh1co2.xls.
23 See also Mountain States Legal Foundation v. Glickman, 92 F. 3d
1228, 1234 (CADC 1996) (“The more drastic the injury that government
action makes more likely, the lesser the increment in probability to
establish standing”); Village of Elk Grove Village v. Evans, 997 F. 2d
328, 329 (CA7 1993) (“[E]ven a small probability of injury is sufficient
Cite as: 549 U. S. ____ (2007) 23
Opinion of the Court
that developing countries such as China and India are
poised to increase greenhouse gas emissions substantially
over the next century: A reduction in domestic emissions
would slow the pace of global emissions increases, no
matter what happens elsewhere.
We moreover attach considerable significance to EPA’s
“agree[ment] with the President that ‘we must address the
issue of global climate change,’ ” 68 Fed. Reg. 52929 (quot
ing remarks announcing Clear Skies and Global Climate
Initiatives, 2002 Public Papers of George W. Bush, Vol. 1,
Feb. 14, p. 227 (2004)), and to EPA’s ardent support for
various voluntary emission-reduction programs, 68 Fed.
Reg. 52932. As Judge Tatel observed in dissent below,
“EPA would presumably not bother with such efforts if it
thought emissions reductions would have no discernable
impact on future global warming.” 415 F. 3d, at 66.
In sum—at least according to petitioners’ uncontested
affidavits—the rise in sea levels associated with global
warming has already harmed and will continue to harm
Massachusetts. The risk of catastrophic harm, though
remote, is nevertheless real. That risk would be reduced
to some extent if petitioners received the relief they seek.
We therefore hold that petitioners have standing to chal
lenge the EPA’s denial of their rulemaking petition.24
——————
to create a case or controversy—to take a suit out of the category of the
hypothetical—provided of course that the relief sought would, if
granted, reduce the probability”).
24 In his dissent, THE CHIEF JUSTICE expresses disagreement with the
Court’s holding in United States v. Students Challenging Regulatory
Agency Procedures (SCRAP), 412 U. S. 669, 687–688 (1973). He does
not, however, disavow this portion of Justice Stewart’s opinion for the
Court:
“Unlike the specific and geographically limited federal action of which
the petitioner complained in Sierra Club [v. Morton, 405 U. S. 727
(1972)], the challenged agency action in this case is applicable to
substantially all of the Nation’s railroads, and thus allegedly has an
adverse environmental impact on all the natural resources of the
24 MASSACHUSETTS v. EPA
Opinion of the Court
V
The scope of our review of the merits of the statutory
issues is narrow. As we have repeated time and again, an
agency has broad discretion to choose how best to marshal
its limited resources and personnel to carry out its dele
gated responsibilities. See Chevron U. S. A. Inc. v. Natu
ral Resources Defense Council, Inc., 467 U. S. 837, 842–845
(1984). That discretion is at its height when the agency
decides not to bring an enforcement action. Therefore, in
Heckler v. Chaney, 470 U. S. 821 (1985), we held that an
agency’s refusal to initiate enforcement proceedings is not
ordinarily subject to judicial review. Some debate re
mains, however, as to the rigor with which we review an
agency’s denial of a petition for rulemaking.
There are key differences between a denial of a petition
for rulemaking and an agency’s decision not to initiate an
enforcement action. See American Horse Protection Assn.,
Inc. v. Lyng, 812 F. 2d 1, 3–4 (CADC 1987). In contrast to
nonenforcement decisions, agency refusals to initiate
rulemaking “are less frequent, more apt to involve legal as
opposed to factual analysis, and subject to special formali
——————
country. Rather than a limited group of persons who used a pictur
esque valley in California, all persons who utilize the scenic resources
of the country, and indeed all who breathe its air, could claim harm
similar to that alleged by the environmental groups here. But we have
already made it clear that standing is not to be denied simply because
many people suffer the same injury. Indeed some of the cases on which
we relied in Sierra Club demonstrated the patent fact that persons
across the Nation could be adversely affected by major governmental
actions. To deny standing to persons who are in fact injured simply
because many others are also injured, would mean that the most injuri
ous and widespread Government actions could be questioned by nobody.
We cannot accept that conclusion.” Ibid. (citations omitted and empha
sis added).
It is moreover quite wrong to analogize the legal claim advanced by
Massachusetts and the other public and private entities who challenge
EPA’s parsimonious construction of the Clean Air Act to a mere “law
yer’s game.” See post, at 14.
Cite as: 549 U. S. ____ (2007) 25
Opinion of the Court
ties, including a public explanation.” Id., at 4; see also 5
U. S. C. §555(e). They moreover arise out of denials of
petitions for rulemaking which (at least in the circum
stances here) the affected party had an undoubted proce
dural right to file in the first instance. Refusals to prom
ulgate rules are thus susceptible to judicial review, though
such review is “extremely limited” and “highly deferen
tial.” National Customs Brokers & Forwarders Assn of
America, Inc. v. United States, 883 F. 2d 93, 96 (CADC
1989).
EPA concluded in its denial of the petition for rulemak
ing that it lacked authority under 42 U. S. C. §7521(a)(1)
to regulate new vehicle emissions because carbon dioxide
is not an “air pollutant” as that term is defined in §7602.
In the alternative, it concluded that even if it possessed
authority, it would decline to do so because regulation
would conflict with other administration priorities. As
discussed earlier, the Clean Air Act expressly permits
review of such an action. §7607(b)(1). We therefore “may
reverse any such action found to be . . . arbitrary, capri
cious, an abuse of discretion, or otherwise not in accor
dance with law.” §7607(d)(9).
VI
On the merits, the first question is whether §202(a)(1) of
the Clean Air Act authorizes EPA to regulate greenhouse
gas emissions from new motor vehicles in the event that it
forms a “judgment” that such emissions contribute to
climate change. We have little trouble concluding that it
does. In relevant part, §202(a)(1) provides that EPA “shall
by regulation prescribe . . . 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
[the Administrator’s] judgment cause, or contribute to, air
pollution which may reasonably be anticipated to endan
ger public health or welfare.” 42 U. S. C. §7521(a)(1).
26 MASSACHUSETTS v. EPA
Opinion of the Court
Because EPA believes that Congress did not intend it to
regulate substances that contribute to climate change, the
agency maintains that carbon dioxide is not an “air pollut
ant” within the meaning of the provision.
The statutory text forecloses EPA’s reading. 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 . . . .” §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.”25 Carbon dioxide, methane, nitrous
oxide, and hydrofluorocarbons are without a doubt “physi
cal [and] chemical . . . substance[s] which [are] emitted
into . . . the ambient air.” The statute is unambiguous.26
Rather than relying on statutory text, EPA invokes
——————
25 See Department of Housing and Urban Development v. Rucker, 535
U. S. 125, 131 (2002) (observing that “ ‘any’ . . . has an expansive mean
ing, that is, one or some indiscriminately of whatever kind” (some inter
nal quotation marks omitted)).
26 In dissent, JUSTICE SCALIA maintains that because greenhouse
gases permeate the world’s atmosphere rather than a limited area near
the earth’s surface, EPA’s exclusion of greenhouse gases from the
category of air pollution “agent[s]” is entitled to deference under Chev
ron U. S. A. Inc. v. Natural Resources Defense Council, Inc. 467 U. S.
837 (1984). See post, at 11–13. EPA’s distinction, however, finds no
support in the text of the statute, which uses the phrase “the ambient
air” without distinguishing between atmospheric layers. Moreover, it is
a plainly unreasonable reading of a sweeping statutory provision
designed to capture “any physical, chemical . . . substance or matter
which is emitted into or otherwise enters the ambient air.” 42 U. S. C.
§7602(g). JUSTICE SCALIA does not (and cannot) explain why Congress
would define “air pollutant” so carefully and so broadly, yet confer on
EPA the authority to narrow that definition whenever expedient by
asserting that a particular substance is not an “agent.” At any rate, no
party to this dispute contests that greenhouse gases both “ente[r] the
ambient air” and tend to warm the atmosphere. They are therefore
unquestionably “agent[s]” of air pollution.
Cite as: 549 U. S. ____ (2007) 27
Opinion of the Court
postenactment congressional actions and deliberations it
views as tantamount to a congressional command to re
frain from regulating greenhouse gas emissions. Even if
such postenactment legislative history could shed light on
the meaning of an otherwise-unambiguous statute, EPA
never identifies any action remotely suggesting that Con
gress meant to curtail its power to treat greenhouse gases
as air pollutants. That subsequent Congresses have es
chewed enacting binding emissions limitations to combat
global warming tells us nothing about what Congress
meant when it amended §202(a)(1) in 1970 and 1977.27
And unlike EPA, we have no difficulty reconciling Con
gress’ various efforts to promote interagency collaboration
and research to better understand climate change28 with
the agency’s pre-existing mandate to regulate “any air
pollutant” that may endanger the public welfare. See 42
U. S. C. §7601(a)(1). Collaboration and research do not
——————
27 See United States v. Price, 361 U. S. 304, 313 (1960) (holding that
“the views of a subsequent Congress form a hazardous basis for infer
ring the intent of an earlier one”); see also Cobell v. Norton, 428 F. 3d
1070, 1075 (CADC 2005) (“[P]ost-enactment legislative history is not
only oxymoronic but inherently entitled to little weight”).
28 See, e.g., National Climate Program Act, §5, 92 Stat. 601, 15 U. S. C.
§2901 et seq. (calling for the establishment of a National Climate
Program and for additional climate change research); Global Climate
Protection Act of 1987, §1103, 101 Stat. 1408–1409 (directing EPA and
the Secretary of State to “jointly” develop a “coordinated national policy
on global climate change” and report to Congress); Global Change
Research Act of 1990, Tit. I, 104 Stat. 3097, 15 U. S. C. §§2921–2938
(establishing for the “development and coordination of a comprehensive
and integrated United States research program” to aid in “under
stand[ing] . . . human-induced and natural processes of climate
change”); Global Climate Change Prevention Act of 1990, 104 Stat.
4058, 7 U. S. C. §6701 et seq. (directing the Dept. of Agriculture to
study the effects of climate change on forestry and agriculture); Energy
Policy Act of 1992, §§1601–1609, 106 Stat. 2999, 42 U. S. C. §§13381–
13388 (requiring the Secretary of Energy to report on information
pertaining to climate change).
28 MASSACHUSETTS v. EPA
Opinion of the Court
conflict with any thoughtful regulatory effort; they com
plement it.29
EPA’s reliance on Brown & Williamson Tobacco Corp.,
529 U. S. 120, is similarly misplaced. In holding that
tobacco products are not “drugs” or “devices” subject to
Food and Drug Administration (FDA) regulation pursuant
to the Food, Drug and Cosmetic Act (FDCA), see 529 U. S.,
at 133, we found critical at least two considerations that
have no counterpart in this case.
First, we thought it unlikely that Congress meant to ban
tobacco products, which the FDCA would have required
had such products been classified as “drugs” or “devices.”
Id., at 135–137. Here, in contrast, EPA jurisdiction would
lead to no such extreme measures. EPA would only regu
late emissions, and even then, it would have to delay any
action “to permit the development and application of the
requisite technology, giving appropriate consideration to
the cost of compliance,” §7521(a)(2). However much a ban
on tobacco products clashed with the “common sense”
intuition that Congress never meant to remove those
products from circulation, Brown & Williamson, 529 U. S.,
at 133, there is nothing counterintuitive to the notion that
EPA can curtail the emission of substances that are put
ting the global climate out of kilter.
Second, in Brown & Williamson we pointed to an unbro
ken series of congressional enactments that made sense
only if adopted “against the backdrop of the FDA’s consis
tent and repeated statements that it lacked authority under
the FDCA to regulate tobacco.” Id., at 144. We can point to
no such enactments here: EPA has not identified any con
gressional action that conflicts in any way with the regula
——————
29 We are moreover puzzled by EPA’s roundabout argument that be
cause later Congresses chose to address stratospheric ozone pollution in
a specific legislative provision, it somehow follows that greenhouse
gases cannot be air pollutants within the meaning of the Clean Air Act.
Cite as: 549 U. S. ____ (2007) 29
Opinion of the Court
tion of greenhouse gases from new motor vehicles. Even if
it had, Congress could not have acted against a regulatory
“backdrop” of disclaimers of regulatory authority. Prior to
the order that provoked this litigation, EPA had never
disavowed the authority to regulate greenhouse gases, and
in 1998 it in fact affirmed that it had such authority. See
App. 54 (Cannon memorandum). There is no reason, much
less a compelling reason, to accept EPA’s invitation to read
ambiguity into a clear statute.
EPA finally argues that it cannot regulate carbon diox
ide emissions from motor vehicles because doing so would
require it to tighten mileage standards, a job (according to
EPA) that Congress has assigned to DOT. See 68 Fed.
Reg. 52929. But that DOT sets mileage standards in no
way licenses EPA to shirk its environmental responsibili
ties. EPA has been charged with protecting the public’s
“health” and “welfare,” 42 U. S. C. §7521(a)(1), a statutory
obligation wholly independent of DOT’s mandate to pro
mote energy efficiency. See Energy Policy and Conserva
tion Act, §2(5), 89 Stat. 874, 42 U. S. C. §6201(5). The two
obligations may overlap, but there is no reason to think
the two agencies cannot both administer their obligations
and yet avoid inconsistency.
While the Congresses that drafted §202(a)(1) might not
have appreciated the possibility that burning fossil fuels
could lead to global warming, they did understand that
without regulatory flexibility, changing circumstances and
scientific developments would soon render the Clean Air
Act obsolete. The broad language of §202(a)(1) reflects an
intentional effort to confer the flexibility necessary to
forestall such obsolescence. See Pennsylvania Dept. of
Corrections v. Yeskey, 524 U. S. 206, 212 (1998) (“[T]he
fact that a statute can be applied in situations not ex
pressly anticipated by Congress does not demonstrate
ambiguity. It demonstrates breadth” (internal quotation
marks omitted)). Because greenhouse gases fit well within
30 MASSACHUSETTS v. EPA
Opinion of the Court
the Clean Air Act’s capacious definition of “air pollutant,”
we hold that EPA has the statutory authority to regulate
the emission of such gases from new motor vehicles.
VII
The alternative basis for EPA’s decision—that even if it
does have statutory authority to regulate greenhouse
gases, it would be unwise to do so at this time—rests on
reasoning divorced from the statutory text. While the
statute does condition the exercise of EPA’s authority on
its formation of a “judgment,” 42 U. S. C. §7521(a)(1), that
judgment must relate to whether an air pollutant
“cause[s], or contribute[s] to, air pollution which may
reasonably be anticipated to endanger public health or
welfare,” ibid. Put another way, the use of the word “judg
ment” is not a roving license to ignore the statutory text.
It is but a direction to exercise discretion within defined
statutory limits.
If EPA makes a finding of endangerment, the Clean Air
Act requires the agency to regulate emissions of the dele
terious pollutant from new motor vehicles. Ibid. (stating
that “[EPA] shall by regulation prescribe . . . standards
applicable to the emission of any air pollutant from any
class of new motor vehicles”). EPA no doubt has signifi
cant latitude as to the manner, timing, content, and coor
dination of its regulations with those of other agencies.
But once EPA has responded to a petition for rulemaking,
its reasons for action or inaction must conform to the
authorizing statute. Under the clear terms of the Clean
Air Act, 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 explana
tion as to why it cannot or will not exercise its discretion
to determine whether they do. Ibid. To the extent that
this constrains agency discretion to pursue other priorities
of the Administrator or the President, this is the congres
sional design.
Cite as: 549 U. S. ____ (2007) 31
Opinion of the Court
EPA has refused to comply with this clear statutory
command. Instead, it has offered a laundry list of reasons
not to regulate. For example, EPA said that a number of
voluntary executive branch programs already provide an
effective response to the threat of global warming, 68 Fed.
Reg. 52932, that regulating greenhouse gases might im
pair the President’s ability to negotiate with “key develop
ing nations” to reduce emissions, id., at 52931, and that
curtailing motor-vehicle emissions would reflect “an ineffi
cient, piecemeal approach to address the climate change
issue,” ibid.
Although we have neither the expertise nor the author
ity to evaluate these policy judgments, it is evident they
have nothing to do with whether greenhouse gas emis
sions contribute to climate change. Still less do they
amount to a reasoned justification for declining to form a
scientific judgment. In particular, while the President has
broad authority in foreign affairs, that authority does not
extend to the refusal to execute domestic laws. In the
Global Climate Protection Act of 1987, Congress author
ized the State Department—not EPA—to formulate United
States foreign policy with reference to environmental mat
ters relating to climate. See §1103(c), 101 Stat. 1409. EPA
has made no showing that it issued the ruling in question
here after consultation with the State Department. Con
gress did direct EPA to consult with other agencies in the
formulation of its policies and rules, but the State Depart
ment is absent from that list. §1103(b).
Nor can EPA avoid its statutory obligation by noting the
uncertainty surrounding various features of climate change
and concluding that it would therefore be better not to
regulate at this time. See 68 Fed. Reg. 52930–52931. If the
scientific uncertainty is so profound that it precludes EPA
from making a reasoned judgment as to whether green
house gases contribute to global warming, EPA must say
so. That EPA would prefer not to regulate greenhouse
32 MASSACHUSETTS v. EPA
Opinion of the Court
gases because of some residual uncertainty—which, con
trary to JUSTICE SCALIA’s apparent belief, post, at 5–8, is
in fact all that it said, see 68 Fed. Reg. 52929 (“We do not
believe . . . that it would be either effective or appropriate
for EPA to establish [greenhouse gas] standards for motor
vehicles at this time” (emphasis added))—is irrelevant.
The statutory question is whether sufficient information
exists to make an endangerment finding.
In short, EPA has offered no reasoned explanation for
its refusal to decide whether greenhouse gases cause or
contribute to climate change. Its action was therefore
“arbitrary, capricious, . . . or otherwise not in accordance
with law.” 42 U. S. C. §7607(d)(9)(A). We need not and do
not reach the question whether on remand EPA must
make an endangerment finding, or whether policy con
cerns can inform EPA’s actions in the event that it makes
such a finding. Cf. Chevron U. S. A. Inc. v. Natural Re
sources Defense Council, Inc., 467 U. S. 837, 843–844
(1984). We hold only that EPA must ground its reasons
for action or inaction in the statute.
VIII
The judgment of the Court of Appeals is reversed, and
the case is remanded for further proceedings consistent
with this opinion.
It is so ordered.
Cite as: 549 U. S. ____ (2007) 1
ROBERTS, C. J., dissenting
SUPREME COURT OF THE UNITED STATES
_________________
No. 05–1120
_________________
MASSACHUSETTS, ET AL., PETITIONERS v. ENVIRON
MENTAL PROTECTION AGENCY ET AL.
ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF
APPEALS FOR THE DISTRICT OF COLUMBIA CIRCUIT
[April 2, 2007]
CHIEF JUSTICE ROBERTS, with whom JUSTICE SCALIA,
JUSTICE THOMAS, and JUSTICE ALITO join, dissenting.
Global warming may be a “crisis,” even “the most press
ing environmental problem of our time.” Pet. for Cert. 26,
22. Indeed, it may ultimately affect nearly everyone on
the planet in some potentially adverse way, and it may be
that governments have done too little to address it. It is
not a problem, however, that has escaped the attention of
policymakers in the Executive and Legislative Branches of
our Government, who continue to consider regulatory,
legislative, and treaty-based means of addressing global
climate change.
Apparently dissatisfied with the pace of progress on this
issue in the elected branches, petitioners have come to the
courts claiming broad-ranging injury, and attempting to
tie that injury to the Government’s alleged failure to
comply with a rather narrow statutory provision. I would
reject these challenges as nonjusticiable. Such a conclu
sion involves no judgment on whether global warming
exists, what causes it, or the extent of the problem. Nor
does it render petitioners without recourse. This Court’s
standing jurisprudence simply recognizes that redress of
grievances of the sort at issue here “is the function of
Congress and the Chief Executive,” not the federal courts.
Lujan v. Defenders of Wildlife, 504 U. S. 555, 576 (1992). I
2 MASSACHUSETTS v. EPA
ROBERTS, C. J., dissenting
would vacate the judgment below and remand for dis
missal of the petitions for review.
I
Article III, §2, of the Constitution limits the federal
judicial power to the adjudication of “Cases” and “Contro
versies.” “If a dispute is not a proper case or controversy,
the courts have no business deciding it, or expounding the
law in the course of doing so.” DaimlerChrysler Corp. v.
Cuno, 547 U. S. ___, ___ (2006) (slip op., at 5). “Standing
to sue is part of the common understanding of what it
takes to make a justiciable case,” Steel Co. v. Citizens for
Better Environment, 523 U. S. 83, 102 (1998), and has
been described as “an essential and unchanging part of the
case-or-controversy requirement of Article III,” Defenders
of Wildlife, supra, at 560.
Our modern framework for addressing standing is famil
iar: “A plaintiff must allege personal injury fairly trace
able to the defendant’s allegedly unlawful conduct and
likely to be redressed by the requested relief.” Daimler-
Chrysler, supra, at ___ (slip op., at 6) (quoting Allen v.
Wright, 468 U. S. 737, 751 (1984) (internal quotation
marks omitted)). Applying that standard here, petitioners
bear the burden of alleging an injury that is fairly trace
able to the Environmental Protection Agency’s failure to
promulgate new motor vehicle greenhouse gas emission
standards, and that is likely to be redressed by the pro
spective issuance of such standards.
Before determining whether petitioners can meet this
familiar test, however, the Court changes the rules. It
asserts that “States are not normal litigants for the pur
poses of invoking federal jurisdiction,” and that given
“Massachusetts’ stake in protecting its quasi-sovereign
interests, the Commonwealth is entitled to special solici
tude in our standing analysis.” Ante, at 15, 17 (emphasis
added).
Cite as: 549 U. S. ____ (2007) 3
ROBERTS, C. J., dissenting
Relaxing Article III standing requirements because
asserted injuries are pressed by a State, however, has no
basis in our jurisprudence, and support for any such “spe
cial solicitude” is conspicuously absent from the Court’s
opinion. The general judicial review provision cited by the
Court, 42 U. S. C. §7607(b)(1), affords States no special
rights or status. The Court states that “Congress has
ordered EPA to protect Massachusetts (among others)”
through the statutory provision at issue, §7521(a)(1), and
that “Congress has . . . recognized a concomitant proce
dural right to challenge the rejection of its rulemaking
petition as arbitrary and capricious.” Ante, at 16. The
reader might think from this unfortunate phrasing that
Congress said something about the rights of States in this
particular provision of the statute. Congress knows how
to do that when it wants to, see, e.g., §7426(b) (affording
States the right to petition EPA to directly regulate cer
tain sources of pollution), but it has done nothing of the
sort here. Under the law on which petitioners rely, Con
gress treated public and private litigants exactly the same.
Nor does the case law cited by the Court provide any
support for the notion that Article III somehow implicitly
treats public and private litigants differently. The Court
has to go back a full century in an attempt to justify its
novel standing rule, but even there it comes up short. The
Court’s analysis hinges on Georgia v. Tennessee Copper
Co., 206 U. S. 230 (1907)—a case that did indeed draw a
distinction between a State and private litigants, but
solely with respect to available remedies. The case had
nothing to do with Article III standing.
In Tennessee Copper, the State of Georgia sought to
enjoin copper companies in neighboring Tennessee from
discharging pollutants that were inflicting “a wholesale
destruction of forests, orchards and crops” in bordering
Georgia counties. Id., at 236. Although the State owned
very little of the territory allegedly affected, the Court
4 MASSACHUSETTS v. EPA
ROBERTS, C. J., dissenting
reasoned that Georgia—in its capacity as a “quasi
sovereign”—“has an interest independent of and behind
the titles of its citizens, in all the earth and air within its
domain.” Id., at 237. The Court explained that while
“[t]he very elements that would be relied upon in a suit
between fellow-citizens as a ground for equitable relief
[were] wanting,” a State “is not lightly to be required to
give up quasi-sovereign rights for pay.” Ibid. Thus while
a complaining private litigant would have to make do with
a legal remedy—one “for pay”—the State was entitled to
equitable relief. See id., at 237–238.
In contrast to the present case, there was no question in
Tennessee Copper about Article III injury. See id., at 238–
239. There was certainly no suggestion that the State
could show standing where the private parties could not;
there was no dispute, after all, that the private landown
ers had “an action at law.” Id., at 238. Tennessee Copper
has since stood for nothing more than a State’s right, in an
original jurisdiction action, to sue in a representative
capacity as parens patriae. See, e.g., Maryland v. Louisi
ana, 451 U. S. 725, 737 (1981). Nothing about a State’s
ability to sue in that capacity dilutes the bedrock require
ment of showing injury, causation, and redressability to
satisfy Article III.
A claim of parens patriae standing is distinct from an
allegation of direct injury. See Wyoming v. Oklahoma, 502
U. S. 437, 448–449, 451 (1992). Far from being a substi
tute for Article III injury, parens patriae actions raise an
additional hurdle for a state litigant: the articulation of a
“quasi-sovereign interest” “apart from the interests of
particular private parties.” Alfred L. Snapp & Son, Inc. v.
Puerto Rico ex rel. Barez, 458 U. S. 592, 607 (1982) (em
phasis added) (cited ante, at 16). Just as an association
suing on behalf of its members must show not only that it
represents the members but that at least one satisfies
Article III requirements, so too a State asserting quasi
Cite as: 549 U. S. ____ (2007) 5
ROBERTS, C. J., dissenting
sovereign interests as parens patriae must still show that
its citizens satisfy Article III. Focusing on Massachu
setts’s interests as quasi-sovereign makes the required
showing here harder, not easier. The Court, in effect,
takes what has always been regarded as a necessary condi
tion for parens patriae standing—a quasi-sovereign inter
est—and converts it into a sufficient showing for purposes
of Article III.
What is more, the Court’s reasoning falters on its own
terms. The Court asserts that Massachusetts is entitled
to “special solicitude” due to its “quasi-sovereign inter
ests,” ante, at 17, but then applies our Article III standing
test to the asserted injury of the State’s loss of coastal
property. See ante, at 19 (concluding that Massachusetts
“has alleged a particularized injury in its capacity as a
landowner” (emphasis added)). In the context of parens
patriae standing, however, we have characterized state
ownership of land as a “nonsovereign interes[t]” because a
State “is likely to have the same interests as other simi
larly situated proprietors.” Alfred L. Snapp & Son, supra,
at 601.
On top of everything else, the Court overlooks the fact
that our cases cast significant doubt on a State’s standing
to assert a quasi-sovereign interest—as opposed to a direct
injury—against the Federal Government. As a general
rule, we have held that while a State might assert a quasi-
sovereign right as parens patriae “for the protection of its
citizens, it is no part of its duty or power to enforce their
rights in respect of their relations with the Federal Gov
ernment. In that field it is the United States, and not the
State, which represents them.” Massachusetts v. Mellon,
262 U. S. 447, 485–486 (1923) (citation omitted); see also
Alfred L. Snapp & Son, supra, at 610, n. 16.
All of this presumably explains why petitioners never
cited Tennessee Copper in their briefs before this Court or
the D. C. Circuit. It presumably explains why not one of
6 MASSACHUSETTS v. EPA
ROBERTS, C. J., dissenting
the legion of amici supporting petitioners ever cited the
case. And it presumably explains why not one of the three
judges writing below ever cited the case either. Given that
one purpose of the standing requirement is “ ‘to assure
that concrete adverseness which sharpens the presenta
tion of issues upon which the court so largely depends for
illumination,’ ” ante, at 13–14 (quoting Baker v. Carr, 369
U. S. 186, 204 (1962)), it is ironic that the Court today
adopts a new theory of Article III standing for States
without the benefit of briefing or argument on the point.1
II
It is not at all clear how the Court’s “special solicitude”
for Massachusetts plays out in the standing analysis,
except as an implicit concession that petitioners cannot
establish standing on traditional terms. But the status of
Massachusetts as a State cannot compensate for petition
ers’ failure to demonstrate injury in fact, causation, and
redressability.
When the Court actually applies the three-part test, it
focuses, as did the dissent below, see 415 F. 3d 50, 64
——————
1 The Court seems to think we do not recognize that Tennessee Copper
is a case about parens patriae standing, ante, at 17, n. 17, but we have
no doubt about that. The point is that nothing in our cases (or Hart &
Wechsler) suggests that the prudential requirements for parens patriae
standing, see Republic of Venezuela v. Philip Morris Inc., 287 F. 3d 192,
199, n. (CADC 2002) (observing that “parens patriae is merely a species
of prudential standing” (internal quotation marks omitted)), can
somehow substitute for, or alter the content of, the “irreducible consti
tutional minimum” requirements of injury in fact, causation, and
redressability under Article III. Lujan v. Defenders of Wildlife, 504
U. S. 555, 560 (1992).
Georgia v. Pennsylvania R. Co., 324 U. S. 439 (1945), is not to the
contrary. As the caption makes clear enough, the fact that a State may
assert rights under a federal statute as parens patriae in no way refutes
our clear ruling that “[a] State does not have standing as parens patriae
to bring an action against the Federal Government.” Alfred L. Snapp &
Son, Inc. v. Puerto Rico ex rel. Barez, 458 U. S. 592, 610, n. 16 (1982).
Cite as: 549 U. S. ____ (2007) 7
ROBERTS, C. J., dissenting
(CADC 2005) (opinion of Tatel, J.), on the State’s asserted
loss of coastal land as the injury in fact. If petitioners rely
on loss of land as the Article III injury, however, they
must ground the rest of the standing analysis in that
specific injury. That alleged injury must be “concrete and
particularized,” Defenders of Wildlife, 504 U. S., at 560,
and “distinct and palpable,” Allen, 468 U. S., at 751 (in
ternal quotation marks omitted). Central to this concept
of “particularized” injury is the requirement that a plain
tiff be affected in a “personal and individual way,” Defend
ers of Wildlife, 504 U. S., at 560, n. 1, and seek relief that
“directly and tangibly benefits him” in a manner distinct
from its impact on “the public at large,” id., at 573–574.
Without “particularized injury, there can be no confidence
of ‘a real need to exercise the power of judicial review’ or
that relief can be framed ‘no broader than required by the
precise facts to which the court’s ruling would be applied.’ ”
Warth v. Seldin, 422 U. S. 490, 508 (1975) (quoting
Schlesinger v. Reservists Comm. to Stop the War, 418 U. S.
208, 221–222 (1974)).
The very concept of global warming seems inconsistent
with this particularization requirement. Global warming
is a phenomenon “harmful to humanity at large,” 415
F. 3d, at 60 (Sentelle, J., dissenting in part and concurring
in judgment), and the redress petitioners seek is focused
no more on them than on the public generally—it is liter
ally to change the atmosphere around the world.
If petitioners’ particularized injury is loss of coastal
land, it is also that injury that must be “actual or immi
nent, not conjectural or hypothetical,” Defenders of Wild
life, supra, at 560 (internal quotation marks omitted),
“real and immediate,” Los Angeles v. Lyons, 461 U. S. 95,
102 (1983) (internal quotation marks omitted), and “cer
tainly impending,” Whitmore v. Arkansas, 495 U. S. 149,
158 (1990) (internal quotation marks omitted).
As to “actual” injury, the Court observes that “global sea
8 MASSACHUSETTS v. EPA
ROBERTS, C. J., dissenting
levels rose somewhere between 10 and 20 centimeters over
the 20th century as a result of global warming” and that
“[t]hese rising seas have already begun to swallow Massa
chusetts’ coastal land.” Ante, at 19. But none of petition
ers’ declarations supports that connection. One declara
tion states that “a rise in sea level due to climate change is
occurring on the coast of Massachusetts, in the metropoli
tan Boston area,” but there is no elaboration. Petitioners’
Standing Appendix in No. 03–1361, etc. (CADC), p. 196
(Stdg. App.). And the declarant goes on to identify a “sig
nifican[t]” non-global-warming cause of Boston’s rising sea
level: land subsidence. Id., at 197; see also id., at 216.
Thus, aside from a single conclusory statement, there is
nothing in petitioners’ 43 standing declarations and ac
companying exhibits to support an inference of actual loss
of Massachusetts coastal land from 20th century global
sea level increases. It is pure conjecture.
The Court’s attempts to identify “imminent” or “cer
tainly impending” loss of Massachusetts coastal land fares
no better. See ante, at 19–20. One of petitioners’ decla
rants predicts global warming will cause sea level to rise
by 20 to 70 centimeters by the year 2100. Stdg. App. 216.
Another uses a computer modeling program to map the
Commonwealth’s coastal land and its current elevation,
and calculates that the high-end estimate of sea level rise
would result in the loss of significant state-owned coastal
land. Id., at 179. But the computer modeling program
has a conceded average error of about 30 centimeters and
a maximum observed error of 70 centimeters. Id., at 177–
178. As an initial matter, if it is possible that the model
underrepresents the elevation of coastal land to an extent
equal to or in excess of the projected sea level rise, it is
difficult to put much stock in the predicted loss of land.
But even placing that problem to the side, accepting a
century-long time horizon and a series of compounded
estimates renders requirements of imminence and imme
Cite as: 549 U. S. ____ (2007) 9
ROBERTS, C. J., dissenting
diacy utterly toothless. See Defenders of Wildlife, supra,
at 565, n. 2 (while the concept of “ ‘imminence’ ” in stand
ing doctrine is “somewhat elastic,” it can be “stretched
beyond the breaking point”). “Allegations of possible
future injury do not satisfy the requirements of Art. III. A
threatened injury must be certainly impending to consti
tute injury in fact.” Whitmore, supra, at 158. (internal
quotation marks omitted; emphasis added).
III
Petitioners’ reliance on Massachusetts’s loss of coastal
land as their injury in fact for standing purposes creates
insurmountable problems for them with respect to causa
tion and redressability. To establish standing, petitioners
must show a causal connection between that specific
injury and the lack of new motor vehicle greenhouse gas
emission standards, and that the promulgation of such
standards would likely redress that injury. As is often the
case, the questions of causation and redressability overlap.
See Allen, 468 U. S., at 753, n. 19 (observing that the two
requirements were “initially articulated by this Court as
two facets of a single causation requirement” (internal
quotation marks omitted)). And importantly, when a
party is challenging the Government’s allegedly unlawful
regulation, or lack of regulation, of a third party, satisfy
ing the causation and redressability requirements be
comes “substantially more difficult.” Defenders of Wildlife,
supra, at 562 (internal quotation marks omitted); see also
Warth, supra, at 504–505.
Petitioners view the relationship between their injuries
and EPA’s failure to promulgate new motor vehicle green
house gas emission standards as simple and direct: Do
mestic motor vehicles emit carbon dioxide and other
greenhouse gases. Worldwide emissions of greenhouse
gases contribute to global warming and therefore also to
petitioners’ alleged injuries. Without the new vehicle
10 MASSACHUSETTS v. EPA
ROBERTS, C. J., dissenting
standards, greenhouse gas emissions—and therefore
global warming and its attendant harms—have been
higher than they otherwise would have been; once EPA
changes course, the trend will be reversed.
The Court ignores the complexities of global warming,
and does so by now disregarding the “particularized”
injury it relied on in step one, and using the dire nature of
global warming itself as a bootstrap for finding causation
and redressability. First, it is important to recognize the
extent of the emissions at issue here. Because local
greenhouse gas emissions disperse throughout the atmos
phere and remain there for anywhere from 50 to 200
years, it is global emissions data that are relevant. See
App. to Pet. for Cert. A–73. According to one of petition
ers’ declarations, domestic motor vehicles contribute about
6 percent of global carbon dioxide emissions and 4 percent
of global greenhouse gas emissions. Stdg. App. 232. The
amount of global emissions at issue here is smaller still;
§202(a)(1) of the Clean Air Act covers only new motor
vehicles and new motor vehicle engines, so petitioners’
desired emission standards might reduce only a fraction of
4 percent of global emissions.
This gets us only to the relevant greenhouse gas emis
sions; linking them to global warming and ultimately to
petitioners’ alleged injuries next requires consideration of
further complexities. As EPA explained in its denial of
petitioners’ request for rulemaking,
“predicting future climate change necessarily involves
a complex web of economic and physical factors in
cluding: our ability to predict future global anthropo
genic emissions of [greenhouse gases] and aerosols;
the fate of these emissions once they enter the atmos
phere (e.g., what percentage are absorbed by vegeta
tion or are taken up by the oceans); the impact of
those emissions that remain in the atmosphere on the
Cite as: 549 U. S. ____ (2007) 11
ROBERTS, C. J., dissenting
radiative properties of the atmosphere; changes in
critically important climate feedbacks (e.g., changes in
cloud cover and ocean circulation); changes in tem
perature characteristics (e.g., average temperatures,
shifts in daytime and evening temperatures); changes
in other climatic parameters (e.g., shifts in precipita
tion, storms); and ultimately the impact of such
changes on human health and welfare (e.g., increases
or decreases in agricultural productivity, human
health impacts).” App. to Pet. for Cert. A–83 through
A–84.
Petitioners are never able to trace their alleged injuries
back through this complex web to the fractional amount of
global emissions that might have been limited with EPA
standards. In light of the bit-part domestic new motor
vehicle greenhouse gas emissions have played in what
petitioners describe as a 150-year global phenomenon, and
the myriad additional factors bearing on petitioners’ al
leged injury—the loss of Massachusetts coastal land—the
connection is far too speculative to establish causation.
IV
Redressability is even more problematic. To the tenu
ous link between petitioners’ alleged injury and the inde
terminate fractional domestic emissions at issue here, add
the fact that petitioners cannot meaningfully predict what
will come of the 80 percent of global greenhouse gas emis
sions that originate outside the United States. As the
Court acknowledges, “developing countries such as China
and India are poised to increase greenhouse gas emissions
substantially over the next century,” ante, at 23, so the
domestic emissions at issue here may become an increas
ingly marginal portion of global emissions, and any de
creases produced by petitioners’ desired standards are
likely to be overwhelmed many times over by emissions
increases elsewhere in the world.
12 MASSACHUSETTS v. EPA
ROBERTS, C. J., dissenting
Petitioners offer declarations attempting to address this
uncertainty, contending that “[i]f the U. S. takes steps to
reduce motor vehicle emissions, other countries are very
likely to take similar actions regarding their own motor
vehicles using technology developed in response to the
U. S. program.” Stdg. App. 220; see also id., at 311–312.
In other words, do not worry that other countries will
contribute far more to global warming than will U. S.
automobile emissions; someone is bound to invent some
thing, and places like the People’s Republic of China or
India will surely require use of the new technology, re
gardless of cost. The Court previously has explained that
when the existence of an element of standing “depends on
the unfettered choices made by independent actors not
before the courts and whose exercise of broad and legiti
mate discretion the courts cannot presume either to con
trol or to predict,” a party must present facts supporting
an assertion that the actor will proceed in such a manner.
Defenders of Wildlife, 504 U. S., at 562 (quoting ASARCO
Inc. v. Kadish, 490 U. S. 605, 615 (1989) (opinion of
KENNEDY, J.); internal quotation marks omitted). The
declarations’ conclusory (not to say fanciful) statements do
not even come close.
No matter, the Court reasons, because any decrease in
domestic emissions will “slow the pace of global emissions
increases, no matter what happens elsewhere.” Ante, at
23. Every little bit helps, so Massachusetts can sue over
any little bit.
The Court’s sleight-of-hand is in failing to link up the
different elements of the three-part standing test. What
must be likely to be redressed is the particular injury in
fact. The injury the Court looks to is the asserted loss of
land. The Court contends that regulating domestic motor
vehicle emissions will reduce carbon dioxide in the atmos
phere, and therefore redress Massachusetts’s injury. But
even if regulation does reduce emissions—to some inde
Cite as: 549 U. S. ____ (2007) 13
ROBERTS, C. J., dissenting
terminate degree, given events elsewhere in the world—
the Court never explains why that makes it likely that the
injury in fact—the loss of land—will be redressed. School
children know that a kingdom might be lost “all for the
want of a horseshoe nail,” but “likely” redressability is a
different matter. The realities make it pure conjecture to
suppose that EPA regulation of new automobile emissions
will likely prevent the loss of Massachusetts coastal land.
V
Petitioners’ difficulty in demonstrating causation and
redressability is not surprising given the evident mis
match between the source of their alleged injury—
catastrophic global warming—and the narrow subject
matter of the Clean Air Act provision at issue in this suit.
The mismatch suggests that petitioners’ true goal for this
litigation may be more symbolic than anything else. The
constitutional role of the courts, however, is to decide
concrete cases—not to serve as a convenient forum for
policy debates. See Valley Forge Christian College v.
Americans United for Separation of Church and State,
Inc., 454 U. S. 464, 472 (1982) (“[Standing] tends to assure
that the legal questions presented to the court will be
resolved, not in the rarified atmosphere of a debating
society, but in a concrete factual context conducive to
a realistic appreciation of the consequences of judicial
action”).
When dealing with legal doctrine phrased in terms of
what is “fairly” traceable or “likely” to be redressed, it is
perhaps not surprising that the matter is subject to some
debate. But in considering how loosely or rigorously to
define those adverbs, it is vital to keep in mind the pur
pose of the inquiry. The limitation of the judicial power to
cases and controversies “is crucial in maintaining the
tripartite allocation of power set forth in the Constitution.”
DaimlerChrysler, 547 U. S., at ___ (slip op., at 5) (internal
14 MASSACHUSETTS v. EPA
ROBERTS, C. J., dissenting
quotation marks omitted). In my view, the Court today—
addressing Article III’s “core component of standing,”
Defenders of Wildlife, supra, at 560—fails to take this
limitation seriously.
To be fair, it is not the first time the Court has done so.
Today’s decision recalls the previous high-water mark of
diluted standing requirements, United States v. Students
Challenging Regulatory Agency Procedures (SCRAP), 412
U. S. 669 (1973). SCRAP involved “[p]robably the most
attenuated injury conferring Art. III standing” and “surely
went to the very outer limit of the law”—until today.
Whitmore, 495 U. S., at 158–159; see also Lujan v. Na
tional Wildlife Federation, 497 U. S. 871, 889 (1990)
(SCRAP “has never since been emulated by this Court”).
In SCRAP, the Court based an environmental group’s
standing to challenge a railroad freight rate surcharge on
the group’s allegation that increases in railroad rates
would cause an increase in the use of nonrecyclable goods,
resulting in the increased need for natural resources to
produce such goods. According to the group, some of these
resources might be taken from the Washington area,
resulting in increased refuse that might find its way into
area parks, harming the group’s members. 412 U. S., at
688.
Over time, SCRAP became emblematic not of the loose
ness of Article III standing requirements, but of how
utterly manipulable they are if not taken seriously as a
matter of judicial self-restraint. SCRAP made standing
seem a lawyer’s game, rather than a fundamental limita
tion ensuring that courts function as courts and not in
trude on the politically accountable branches. Today’s
decision is SCRAP for a new generation.2
——————
2 The difficulty with SCRAP, and the reason it has not been followed,
is not the portion cited by the Court. See ante, at 23–24, n. 24. Rather,
it is the attenuated nature of the injury there, and here, that is so
Cite as: 549 U. S. ____ (2007) 15
ROBERTS, C. J., dissenting
Perhaps the Court recognizes as much. How else to
explain its need to devise a new doctrine of state standing
to support its result? The good news is that the Court’s
“special solicitude” for Massachusetts limits the future
applicability of the diluted standing requirements applied
in this case. The bad news is that the Court’s self-
professed relaxation of those Article III requirements has
caused us to transgress “the proper—and properly lim
ited—role of the courts in a democratic society.” Allen, 468
U. S., at 750 (internal quotation marks omitted).
I respectfully dissent.
——————
troubling. Even in SCRAP, the Court noted that what was required
was “something more than an ingenious academic exercise in the
conceivable,” 412 U. S., at 688, and we have since understood the
allegation there to have been “that the string of occurrences alleged
would happen immediately,” Whitmore v. Arkansas, 495 U. S. 149, 159
(1990) (emphasis added). That is hardly the case here.
The Court says it is “quite wrong” to compare petitioners’ challenging
“EPA’s parsimonious construction of the Clean Air Act to a mere
‘lawyer’s game.’ ” Ante, at 24, n. 24. Of course it is not the legal chal
lenge that is merely “an ingenious academic exercise in the conceiv
able,” SCRAP, supra, at 688, but the assertions made in support of
standing.
Cite as: 549 U. S. ____ (2007) 1
SCALIA, J., dissenting
SUPREME COURT OF THE UNITED STATES
_________________
No. 05–1120
_________________
MASSACHUSETTS, ET AL., PETITIONERS v. ENVIRON
MENTAL PROTECTION AGENCY ET AL.
ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF
APPEALS FOR THE DISTRICT OF COLUMBIA CIRCUIT
[April 2, 2007]
JUSTICE SCALIA, with whom THE CHIEF JUSTICE,
JUSTICE THOMAS, and JUSTICE ALITO join, dissenting.
I join THE CHIEF JUSTICE’s opinion in full, and would
hold that this Court has no jurisdiction to decide this case
because petitioners lack standing. The Court having
decided otherwise, it is appropriate for me to note my
dissent on the merits.
I
A
The provision of law at the heart of this case is
§202(a)(1) of the Clean Air Act (CAA), which provides that
the Administrator of the Environmental Protection Agency
(EPA) “shall by regulation prescribe . . . standards appli
cable to the emission of any air pollutant from any class or
classes of new motor vehicles or new motor vehicle en
gines, which in his judgment cause, or contribute to, air
pollution which may reasonably be anticipated to endan
ger public health or welfare.” 42 U. S. C. §7521(a)(1)
(emphasis added). As the Court recognizes, the statute
“condition[s] the exercise of EPA’s authority on its forma
tion of a ‘judgment.’ ” Ante, at 30. There is no dispute that
the Administrator has made no such judgment in this
case. See ante, at 32 (“We need not and do not reach the
question whether on remand EPA must make an endan
2 MASSACHUSETTS v. EPA
SCALIA, J., dissenting
germent finding”); 68 Fed. 52929 (2003) (“[N]o Adminis
trator has made a finding under any of the CAA’s regula
tory provisions that CO2 meets the applicable statutory
criteria for regulation”).
The question thus arises: Does anything require the
Administrator to make a “judgment” whenever a petition
for rulemaking is filed? Without citation of the statute or
any other authority, the Court says yes. Why is that so?
When Congress wishes to make private action force an
agency’s hand, it knows how to do so. See, e.g., Brock v.
Pierce County, 476 U. S. 253, 254–255 (1986) (discussing
the Comprehensive Employment and Training Act
(CETA), 92 Stat. 1926, 29 U. S. C. §816(b) (1976 ed., Supp.
V), which “provide[d] that the Secretary of Labor ‘shall’
issue a final determination as to the misuse of CETA
funds by a grant recipient within 120 days after receiving
a complaint alleging such misuse”). Where does the CAA
say that the EPA Administrator is required to come to a
decision on this question whenever a rulemaking petition
is filed? The Court points to no such provision because
none exists.
Instead, the Court invents a multiple-choice question
that the EPA Administrator must answer when a petition
for rulemaking is filed. The Administrator must exercise
his judgment in one of three ways: (a) by concluding that
the pollutant does cause, or contribute to, air pollution
that endangers public welfare (in which case EPA is re
quired to regulate); (b) by concluding that the pollutant
does not cause, or contribute to, air pollution that endan
gers public welfare (in which case EPA is not required to
regulate); or (c) by “provid[ing] some reasonable explana
tion as to why it cannot or will not exercise its discretion
to determine whether” greenhouse gases endanger public
welfare, ante, at 30, (in which case EPA is not required to
regulate).
I am willing to assume, for the sake of argument, that
Cite as: 549 U. S. ____ (2007) 3
SCALIA, J., dissenting
the Administrator’s discretion in this regard is not entirely
unbounded—that if he has no reasonable basis for defer
ring judgment he must grasp the nettle at once. The
Court, however, with no basis in text or precedent, rejects
all of EPA’s stated “policy judgments” as not “amount[ing]
to a reasoned justification,” ante, at 31, effectively narrow
ing the universe of potential reasonable bases to a single
one: Judgment can be delayed only if the Administrator
concludes that “the scientific uncertainty is [too] pro
found.” Ibid. The Administrator is precluded from con
cluding for other reasons “that it would . . . be better not to
regulate at this time.” Ibid.1 Such other reasons—
perfectly valid reasons—were set forth in the agency’s
statement.
“We do not believe . . . that it would be either effective
or appropriate for EPA to establish [greenhouse gas]
standards for motor vehicles at this time. As de
scribed in detail below, the President has laid out a
comprehensive approach to climate change that calls
for near-term voluntary actions and incentives along
with programs aimed at reducing scientific uncertain
ties and encouraging technological development so
that the government may effectively and efficiently
address the climate change issue over the long term.
. . . . .
“[E]stablishing [greenhouse gas] emission standards
for U. S. motor vehicles at this time would . . . result
in an inefficient, piecemeal approach to addressing
the climate change issue. The U. S. motor vehicle
fleet is one of many sources of [greenhouse gas] emis
sions both here and abroad, and different [greenhouse
——————
1 The Court’s way of putting it is, of course, not quite accurate. The
issue is whether it would be better to defer the decision about whether to
exercise judgment. This has the effect of deferring regulation but is
quite a different determination.
4 MASSACHUSETTS v. EPA
SCALIA, J., dissenting
gas] emission sources face different technological and
financial challenges in reducing emissions. A sensible
regulatory scheme would require that all significant
sources and sinks of [greenhouse gas] emissions be
considered in deciding how best to achieve any needed
emission reductions.
“Unilateral EPA regulation of motor vehicle [green
house gas] emissions could also weaken U. S. efforts
to persuade developing countries to reduce the
[greenhouse gas] intensity of their economies. Con
sidering the large populations and growing economies
of some developing countries, increases in their
[greenhouse gas] emissions could quickly overwhelm
the effects of [greenhouse gas] reduction measures in
developed countries. Any potential benefit of EPA
regulation could be lost to the extent other nations de
cided to let their emissions significantly increase in
view of U. S. emissions reductions. Unavoidably, cli
mate change raises important foreign policy issues,
and it is the President’s prerogative to address them.”
68 Fed. Reg. 52929–52931 (footnote omitted).
The Court dismisses this analysis as “rest[ing] on rea
soning divorced from the statutory text.” Ante, at 30.
“While the statute does condition the exercise of EPA’s
authority on its formation of a ‘judgment,’ . . . that judg
ment must relate to whether an air pollutant ‘cause[s], or
contribute[s] to, air pollution which may reasonably be
anticipated to endanger public health or welfare.’ ” Ibid.
True but irrelevant. When the Administrator makes a
judgment whether to regulate greenhouse gases, that
judgment must relate to whether they are air pollutants
that “cause, or contribute to, air pollution which may
reasonably be anticipated to endanger public health or
welfare.” 42 U. S. C. §7521(a)(1). But the statute says
nothing at all about the reasons for which the Administra
Cite as: 549 U. S. ____ (2007) 5
SCALIA, J., dissenting
tor may defer making a judgment—the permissible rea
sons for deciding not to grapple with the issue at the
present time. Thus, the various “policy” rationales, ante,
at 31, that the Court criticizes are not “divorced from the
statutory text,” ante, at 30, except in the sense that the
statutory text is silent, as texts are often silent about
permissible reasons for the exercise of agency discretion.
The reasons the EPA gave are surely considerations ex
ecutive agencies regularly take into account (and ought to
take into account) when deciding whether to consider
entering a new field: the impact such entry would have on
other Executive Branch programs and on foreign policy.
There is no basis in law for the Court’s imposed limitation.
EPA’s interpretation of the discretion conferred by the
statutory reference to “its judgment” is not only reason
able, it is the most natural reading of the text. The Court
nowhere explains why this interpretation is incorrect, let
alone why it is not entitled to deference under Chevron
U. S. A. Inc. v. Natural Resources Defense Council, Inc.,
467 U. S. 837 (1984). As the Administrator acted within
the law in declining to make a “judgment” for the policy
reasons above set forth, I would uphold the decision to
deny the rulemaking petition on that ground alone.
B
Even on the Court’s own terms, however, the same
conclusion follows. As mentioned above, the Court gives
EPA the option of determining that the science is too
uncertain to allow it to form a “judgment” as to whether
greenhouse gases endanger public welfare. Attached to
this option (on what basis is unclear) is an essay require
ment: “If,” the Court says, “the scientific uncertainty is so
profound that it precludes EPA from making a reasoned
judgment as to whether greenhouse gases contribute to
global warming, EPA must say so.” Ante, at 31. But EPA
has said precisely that—and at great length, based on
6 MASSACHUSETTS v. EPA
SCALIA, J., dissenting
information contained in a 2001 report by the National
Research Council (NRC) entitled Climate Change Science:
An Analysis of Some Key Questions:
“As the NRC noted in its report, concentrations of
[greenhouse gases (GHGs)] are increasing in the at
mosphere as a result of human activities (pp. 9–12).
It also noted that ‘[a] diverse array of evidence points
to a warming of global surface air temperatures’ (p.
16). The report goes on to state, however, that
‘[b]ecause of the large and still uncertain level of
natural variability inherent in the climate record and
the uncertainties in the time histories of the various
forcing agents (and particularly aerosols), a [causal]
linkage between the buildup of greenhouse gases in
the atmosphere and the observed climate changes
during the 20th century cannot be unequivocally es
tablished. The fact that the magnitude of the ob
served warming is large in comparison to natural
variability as simulated in climate models is sugges
tive of such a linkage, but it does not constitute proof
of one because the model simulations could be defi
cient in natural variability on the decadal to century
time scale’ (p. 17).
“The NRC also observed that ‘there is considerable
uncertainty in current understanding of how the cli
mate system varies naturally and reacts to emissions
of [GHGs] and aerosols’ (p. 1). As a result of that un
certainty, the NRC cautioned that ‘current estimate of
the magnitude of future warming should be regarded
as tentative and subject to future adjustments (either
upward or downward).’ Id. It further advised that
‘[r]educing the wide range of uncertainty inherent in
current model predictions of global climate change
will require major advances in understanding and
modeling of both (1) the factors that determine at
Cite as: 549 U. S. ____ (2007) 7
SCALIA, J., dissenting
mospheric concentrations of [GHGs] and aerosols and
(2) the so-called “feedbacks” that determine the sensi
tivity of the climate system to a prescribed increase in
[GHGs].’ Id.
“The science of climate change is extraordinarily
complex and still evolving. Although there have been
substantial advances in climate change science, there
continue to be important uncertainties in our under
standing of the factors that may affect future climate
change and how it should be addressed. As the NRC
explained, predicting future climate change necessar
ily involves a complex web of economic and physical
factors including: Our ability to predict future global
anthropogenic emissions of GHGs and aerosols; the
fate of these emissions once they enter the atmos
phere (e.g., what percentage are absorbed by vegeta
tion or are taken up by the oceans); the impact of
those emissions that remain in the atmosphere on the
radiative properties of the atmosphere; changes in
critically important climate feedbacks (e.g., changes in
cloud cover and ocean circulation); changes in tem
perature characteristics (e.g., average temperatures,
shifts in daytime and evening temperatures); changes
in other climatic parameters (e.g., shifts in precipita
tion, storms); and ultimately the impact of such
changes on human health and welfare (e.g., increases
or decreases in agricultural productivity, human
health impacts). The NRC noted, in particular, that
‘[t]he understanding of the relationships between
weather/climate and human health is in its infancy
and therefore the health consequences of climate
change are poorly understood’ (p. 20). Substantial
scientific uncertainties limit our ability to assess each
of these factors and to separate out those changes re
sulting from natural variability from those that are
directly the result of increases in anthropogenic
8 MASSACHUSETTS v. EPA
SCALIA, J., dissenting
GHGs.
“Reducing the wide range of uncertainty inherent in
current model predictions will require major advances
in understanding and modeling of the factors that de
termine atmospheric concentrations of greenhouse
gases and aerosols, and the processes that determine
the sensitivity of the climate system.” 68 Fed. Reg.
52930.
I simply cannot conceive of what else the Court would like
EPA to say.
II
A
Even before reaching its discussion of the word “judg
ment,” the Court makes another significant error when it
concludes that Ҥ202(a)(1) of the Clean Air Act authorizes
EPA to regulate greenhouse gas emissions from new motor
vehicles in the event that it forms a ‘judgment’ that such
emissions contribute to climate change.” Ante, at 25 (em
phasis added). For such authorization, the Court relies on
what it calls “the Clean Air Act’s capacious definition of
‘air pollutant.’ ” Ante, at 30.
“Air pollutant” is defined by the Act as “any air pollution
agent or combination of such agents, including any physi
cal, chemical, . . . substance or matter which is emitted
into or otherwise enters the ambient air.” 42 U. S. C.
§7602(g). The Court is correct that “[c]arbon dioxide,
methane, nitrous oxide, and hydrofluorocarbons,” ante, at
26, fit within the second half of that definition: They are
“physical, chemical, . . . substance[s] or matter which [are]
emitted into or otherwise ente[r] the ambient air.” But the
Court mistakenly believes this to be the end of the analy
sis. In order to be an “air pollutant” under the Act’s defi
nition, the “substance or matter [being] emitted into . . .
the ambient air” must also meet the first half of the defini
tion—namely, it must be an “air pollution agent or combi
Cite as: 549 U. S. ____ (2007) 9
SCALIA, J., dissenting
nation of such agents.” The Court simply pretends this
half of the definition does not exist.
The Court’s analysis faithfully follows the argument
advanced by petitioners, which focuses on the word “in
cluding” in the statutory definition of “air pollutant.” See
Brief for Petitioners 13–14. As that argument goes, any
thing that follows the word “including” must necessarily
be a subset of whatever precedes it. Thus, if greenhouse
gases qualify under the phrase following the word “includ
ing,” they must qualify under the phrase preceding it.
Since greenhouse gases come within the capacious phrase
“any physical, chemical, . . . substance or matter which is
emitted into or otherwise enters the ambient air,” they
must also be “air pollution agent[s] or combination[s] of
such agents,” and therefore meet the definition of “air
pollutant[s].”
That is certainly one possible interpretation of the
statutory definition. The word “including” can indeed
indicate that what follows will be an “illustrative” sam
pling of the general category that precedes the word.
Federal Land Bank of St. Paul v. Bismarck Lumber Co.,
314 U. S. 95, 100 (1941). Often, however, the examples
standing alone are broader than the general category, and
must be viewed as limited in light of that category. The
Government provides a helpful (and unanswered) exam
ple: “The phrase ‘any American automobile, including any
truck or minivan,’ would not naturally be construed to
encompass a foreign-manufactured [truck or] minivan.”
Brief for Federal Respondent 34. The general principle
enunciated—that the speaker is talking about American
automobiles—carries forward to the illustrative examples
(trucks and minivans), and limits them accordingly, even
though in isolation they are broader. Congress often uses
the word “including” in this manner. In 28 U. S. C.
§1782(a), for example, it refers to “a proceeding in a for
eign or international tribunal, including criminal investi
10 MASSACHUSETTS v. EPA
SCALIA, J., dissenting
gations conducted before formal accusation.” Certainly
this provision would not encompass criminal investiga
tions underway in a domestic tribunal. See also, e.g., 2
U. S. C. §54(a) (“The Clerk of the House of Representatives
shall, at the request of a Member of the House of Repre
sentatives, furnish to the Member, for official use only, one
set of a privately published annotated version of the
United States Code, including supplements and pocket
parts”); 22 U. S. C. §2304(b)(1) (“the relevant findings of
appropriate international organizations, including non
governmental organizations”).
In short, the word “including” does not require the
Court’s (or the petitioners’) result. It is perfectly reason
able to view the definition of “air pollutant” in its entirety:
An air pollutant can be “any physical, chemical, . . . sub
stance or matter which is emitted into or otherwise enters
the ambient air,” but only if it retains the general charac
teristic of being an “air pollution agent or combination of
such agents.” This is precisely the conclusion EPA
reached: “[A] substance does not meet the CAA definition
of ‘air pollutant’ simply because it is a ‘physical, chemical,
. . . substance or matter which is emitted into or otherwise
enters the ambient air.’ It must also be an ‘air pollution
agent.’ ” 68 Fed. Reg. 52929, n. 3. See also id., at 52928
(“The root of the definition indicates that for a substance
to be an ‘air pollutant,’ it must be an ‘agent’ of ‘air pollu
tion’ ”). Once again, in the face of textual ambiguity, the
Court’s application of Chevron deference to EPA’s inter
pretation of the word “including” is nowhere to be found.2
——————
2 Not only is EPA’s interpretation reasonable, it is far more plausible
than the Court’s alternative. As the Court correctly points out, “all
airborne compounds of whatever stripe,” ante, at 26, would qualify as
“physical, chemical, . . . substance[s] or matter which [are] emitted into
or otherwise ente[r] the ambient air,” 42 U. S. C. §7602(g). It follows
that everything airborne, from Frisbees to flatulence, qualifies as an
“air pollutant.” This reading of the statute defies common sense.
Cite as: 549 U. S. ____ (2007) 11
SCALIA, J., dissenting
Evidently, the Court defers only to those reasonable inter
pretations that it favors.
B
Using (as we ought to) EPA’s interpretation of the defi
nition of “air pollutant,” we must next determine whether
greenhouse gases are “agent[s]” of “air pollution.” If so,
the statute would authorize regulation; if not, EPA would
lack authority.
Unlike “air pollutants,” the term “air pollution” is not
itself defined by the CAA; thus, once again we must accept
EPA’s interpretation of that ambiguous term, provided its
interpretation is a “permissible construction of the stat
ute.” Chevron, 467 U. S., at 843. In this case, the petition
for rulemaking asked EPA for “regulation of [greenhouse
gas] emissions from motor vehicles to reduce the risk of
global climate change.” 68 Fed. Reg. 52925. Thus, in
deciding whether it had authority to regulate, EPA had to
determine whether the concentration of greenhouse gases
assertedly responsible for “global climate change” quali
fies as “air pollution.” EPA began with the commonsense
observation that the “[p]roblems associated with atmos
pheric concentrations of CO2,” id., at 52927, bear little
resemblance to what would naturally be termed “air
pollution”:
“EPA’s prior use of the CAA’s general regulatory
provisions provides an important context. Since the
inception of the Act, EPA has used these provisions to
address air pollution problems that occur primarily at
ground level or near the surface of the earth. For ex
ample, national ambient air quality standards
(NAAQS) established under CAA section 109 address
concentrations of substances in the ambient air and
the related public health and welfare problems. This
has meant setting NAAQS for concentrations of ozone,
carbon monoxide, particulate matter and other sub
12 MASSACHUSETTS v. EPA
SCALIA, J., dissenting
stances in the air near the surface of the earth, not
higher in the atmosphere. . . . CO2, by contrast, is
fairly consistent in concentration throughout the
world’s atmosphere up to approximately the lower
stratosphere.” Id., at 52926–52927.
In other words, regulating the buildup of CO2 and other
greenhouse gases in the upper reaches of the atmosphere,
which is alleged to be causing global climate change, is not
akin to regulating the concentration of some substance
that is polluting the air.
We need look no further than the dictionary for confir
mation that this interpretation of “air pollution” is emi
nently reasonable. The definition of “pollute,” of course, is
“[t]o make or render impure or unclean.” Webster’s New
International Dictionary 1910 (2d ed. 1949). And the first
three definitions of “air” are as follows: (1) “[t]he invisible,
odorless, and tasteless mixture of gases which surrounds
the earth”; (2) “[t]he body of the earth’s atmosphere; esp.,
the part of it near the earth, as distinguished from the
upper rarefied part”; (3) “[a] portion of air or of the air
considered with respect to physical characteristics or as
affecting the senses.” Id., at 54. EPA’s conception of “air
pollution”—focusing on impurities in the “ambient air” “at
ground level or near the surface of the earth”—is perfectly
consistent with the natural meaning of that term.
In the end, EPA concluded that since “CAA authoriza
tion to regulate is generally based on a finding that an air
pollutant causes or contributes to air pollution,” 68 Fed.
Reg. 52928, the concentrations of CO2 and other green
house gases allegedly affecting the global climate are
beyond the scope of CAA’s authorization to regulate.
“[T]he term ‘air pollution’ as used in the regulatory provi
sions cannot be interpreted to encompass global climate
change.” Ibid. Once again, the Court utterly fails to
explain why this interpretation is incorrect, let alone so
Cite as: 549 U. S. ____ (2007) 13
SCALIA, J., dissenting
unreasonable as to be unworthy of Chevron deference.
* * *
The Court’s alarm over global warming may or may not
be justified, but it ought not distort the outcome of this
litigation. This is a straightforward administrative-law
case, in which Congress has passed a malleable statute
giving broad discretion, not to us but to an executive
agency. No matter how important the underlying policy
issues at stake, this Court has no business substituting its
own desired outcome for the reasoned judgment of the
responsible agency.