1438 127 supreme court reporter 549 u.s. 583 · 1. federal civil procedure o103.2, 103.3 to...

1438 127 SUPREME COURT REPORTER 549 U.S. 583

Id., at 342–343, 117 S.Ct. 843. According-ly, upon analyzing the context of § 704(a),we were compelled to conclude that theterm ‘‘employee’’ included former employ-ees. This case does not present a similarsituation. The statute here includes astatutory cross-reference, which conveys aclear congressional intent to provide acommon definition for the term ‘‘modifica-tion.’’ And the contextual differences be-tween PSD and NSPS do not compelS 584different meanings for the term ‘‘modifi-cation.’’ Robinson is, therefore, inapplica-ble.

Even if the cross-reference were merelythe equivalent of repeating the words ofthe definition, we must still apply our usu-al presumption that the same words re-peated in different parts of the same stat-ute have the same meaning. See AtlanticCleaners, supra, at 433, 52 S.Ct. 607; ante,at 1432. That presumption has not beenovercome here. While the broadly statedregulatory goals of PSD and NSPS differ,these contextual differences do not compeldifferent definitions of ‘‘modification.’’That is, unlike in Robinson, reading thestatutory definition in the separate con-texts of PSD and NSPS does not requiredifferent interpretations of the term ‘‘mod-ification.’’ EPA demonstrated as muchwhen it recently proposed regulations thatwould unify the regulatory definitions of‘‘modification.’’ See 70 Fed.Reg. 61083, n.3 (2005) (terming the proposal ‘‘an appro-priate exercise of our discretion’’ and stat-ing that the unified definition better servesPSD’s goals).

The majority opinion does little to over-come the presumption that the samewords, when repeated, carry the samemeaning. Instead, it explains that thisCourt’s cases do not compel identical lan-guage to be interpreted identically in allsituations. Granting that point, the major-ity still has the burden of stating why our

general presumption does not control theoutcome here. It has not done so.

,

549 U.S. 497, 167 L.Ed.2d 248

MASSACHUSETTS et al., Petitioners,

v.

ENVIRONMENTAL PROTECTIONAGENCY et al.

No. 05–1120.

Argued Nov. 29, 2006.

Decided April 2, 2007.

Background: States, local governments,and environmental organizations petitionedfor review of an order of the Environmen-tal Protection Agency (EPA) denying apetition for rulemaking to regulate green-house gas emissions from motor vehiclesunder the Clean Air Act. The Court ofAppeals for the District of Columbia Cir-cuit, 415 F.3d 50, dismissed or denied thepetitions. Certiorari was granted.

Holdings: The Supreme Court, JusticeStevens, held that:

(1) state of Massachusetts had standing topetition for review;

(2) Clean Air Act authorizes the EPA toregulate greenhouse gas emissionsfrom new motor vehicles in the eventthat it forms a ‘‘judgment’’ that suchemissions contribute to climate change;and

(3) EPA can avoid taking regulatory ac-tion with respect to greenhouse gasemissions from new motor vehiclesonly if it determines that greenhousegases do not contribute to climatechange or if it provides some reason-able explanation as to why it cannot or

1439MASSACHUSETTS v. E.P.A.Cite as 127 S.Ct. 1438 (2007)

549 U.S. 497

will not exercise its discretion to deter-mine whether they do.

Reversed and remanded.

Chief Justice Roberts filed dissenting opin-ion in which Justices Scalia, Thomas, andAlito joined.

Justice Scalia filed dissenting opinion inwhich Chief Justice Roberts and JusticesThomas and Alito joined.

1. Federal Civil Procedure O103.2, 103.3To demonstrate standing, a litigant

must show that it has suffered a concreteand particularized injury that is either ac-tual or imminent, that the injury is fairlytraceable to the defendant, and that it islikely that a favorable decision will redressthat injury.

2. Federal Civil Procedure O103.2, 103.3A litigant to whom Congress has ac-

corded a procedural right to protect hisconcrete interests can assert that rightwithout meeting the normal standing re-quirements of redressability and immedia-cy; in such a case, the litigant has standingif there is some possibility that the re-quested relief will prompt the injury-caus-ing party to reconsider the decision thatallegedly harmed the litigant.

3. Environmental Law O651On petitions for review of an order of

the Environmental Protection Agency(EPA), only one of the petitioners had tohave standing to permit the SupremeCourt to consider the petition for review.

4. Environmental Law O654State of Massachusetts had standing

to petition for review of order of the Envi-ronmental Protection Agency (EPA) refus-ing to regulate greenhouse gas emissionsfrom motor vehicles under the Clean AirAct, considering that EPA’s refusal to doso presented a risk of harm to Massachu-

setts from rise in sea levels associated withglobal warming that was both ‘‘actual’’ and‘‘imminent,’’ and that there was a substan-tial likelihood that judicial relief requestedwould prompt EPA to take steps to reducethat risk. Clean Air Act, § 101 et seq., 42U.S.C.A. § 7401 et seq.

5. Administrative Law and ProcedureO301, 706

An agency has broad discretion tochoose how best to marshal its limitedresources and personnel to carry out itsdelegated responsibilities; such discretionis at its height when the agency decidesnot to bring an enforcement action.

6. Administrative Law and ProcedureO706

An agency’s refusal to initiate enforce-ment proceedings is not ordinarily subjectto judicial review.

7. Administrative Law and ProcedureO706

Agency refusals to promulgate rulesare susceptible to judicial review, thoughsuch review is extremely limited and high-ly deferential.

8. Environmental Law O273, 276Clean Air Act authorizes the Environ-

mental Protection Agency (EPA) to regu-late greenhouse gas emissions from newmotor vehicles in the event that it forms a‘‘judgment’’ that such emissions contributeto climate change, as carbon dioxide andother greenhouse gases fall within theAct’s capacious definition of ‘‘air pollu-tant.’’ Clean Air Act, § 202(a)(1), 42U.S.C.A. § 7521(a)(1).

See publication Words and Phras-es for other judicial constructionsand definitions.

9. Environmental Law O250, 273, 276Fact that mandate of the Department

of Transportation (DOT) to promote ener-gy efficiency by setting mileage standards


might overlap with environmental respon-sibilities of the Environmental ProtectionAgency (EPA) in no way licensed the EPAto shirk its duty under the Clean Air Actto protect the public ‘‘health’’ and ‘‘wel-fare’’ by regulating greenhouse gas emis-sions from new motor vehicles if it deter-mined that such emissions contribute toclimate change. Energy Policy and Con-servation Act, § 2(5), 42 U.S.C.A.§ 6201(5); Clean Air Act, § 202(a)(1), 42U.S.C.A. § 7521(a)(1).

10. Environmental Law O273, 276Under the clear terms of the Clean

Air Act, the Environmental ProtectionAgency (EPA) can avoid taking regulatoryaction with respect to greenhouse gasemissions from new motor vehicles only ifit determines that greenhouse gases do notcontribute to climate change or if it pro-vides some reasonable explanation as towhy it cannot or will not exercise its dis-cretion to determine whether they do.Clean Air Act, § 202(a)(1), 42 U.S.C.A.§ 7521(a)(1).

11. Environmental Law O273, 276Environmental Protection Agency

(EPA) could not avoid taking regulatoryaction under the Clean Air Act with re-spect to greenhouse gas emissions fromnew motor vehicles based on policy judg-ments that a number of voluntary execu-tive branch programs already provide aneffective response to the threat of globalwarming, that regulating greenhouse gasesmight impair the President’s ability to ne-gotiate with ‘‘key developing nations’’ toreduce emissions, and that curtailing mo-tor-vehicle emissions would reflect ‘‘an in-efficient, piecemeal approach to addressthe climate change issue.’’ Clean Air Act,§ 202(a)(1), 42 U.S.C.A. § 7521(a)(1).

12. Environmental Law O273, 276

Environmental Protection Agency(EPA) could not avoid its statutory obli-gation under the Clean Air Act to regulategreenhouse gas emissions from new motorvehicles by noting uncertainty surroundingvarious features of climate change andconcluding that it would therefore be bet-ter not to regulate at this time; if scientificuncertainty was so profound that it pre-cluded EPA from making a reasoned judg-ment as to whether greenhouse gases con-tribute to global warming, EPA had to sayso, as statutory question was whether suf-ficient information existed to make an en-dangerment finding. Clean Air Act,§ 202(a)(1), 42 U.S.C.A. § 7521(a)(1).

S 497Syllabus *

Based on respected scientific opinionthat a well-documented rise in globaltemperatures and attendant climatologicaland environmental changes have resultedfrom a significant increase in the atmo-spheric concentration of ‘‘greenhouse gas-es,’’ a group of private organizations peti-tioned the Environmental ProtectionAgency (EPA) to begin regulating theemissions of four such gases, including car-bon dioxide, under § 202(a)(1) of the CleanAir Act, which requires that EPA ‘‘shall byregulation prescribe TTT standards applica-ble to the emission of any air pollutantfrom any class TTT of new motor vehiclesTTT which in [the EPA Administrator’s]judgment cause[s], or contribute[s] to, airpollution TTT reasonably TTT anticipated toendanger public health or welfare,’’ 42U.S.C. § 7521(a)(1). The Act defines ‘‘airpollutant’’ to include ‘‘any air pollutionagent TTT, including any physical, chemicalTTT substance TTT emitted into TTT the

* The syllabus constitutes no part of the opinionof the Court but has been prepared by theReporter of Decisions for the convenience of

the reader. See United States v. Detroit Tim-ber & Lumber Co., 200 U.S. 321, 337, 26 S.Ct.282, 50 L.Ed. 499.


549 U.S. 498

ambient air.’’ § 7602(g). EPA ultimatelydenied the petition, reasoning that (1) theAct does not authorize it to issue mandato-ry regulations to address global climatechange, and (2) even if it had the authorityto set greenhouse gas emission standards,it would have been unwise to do so at thattime because a causal link between green-house gases and the increase in globalsurface air temperatures was not unequiv-ocally established. The Agency furthercharacterized any EPA regulation of mo-tor-vehicle emissions as a piecemeal ap-proach to climate change that would con-flict with the President’s comprehensiveapproach involving additional support fortechnological innovation, the creation ofnonregulatory programs to encourage vol-untary private-sector reductions in green-house gas emissions, and further researchon climate change, and might hamper thePresident’s ability to persuade key devel-oping nations to reduce emissions.

Petitioners, now joined by intervenorMassachusetts and other state and localgovernments, sought review in the D.C.Circuit. Although each of the threejudges on the panel wrote separately, twoof them agreed that the EPA Administra-tor properly exercised his discretion indenying the rulemaking petition. Onejudge concluded that the Administrator’sexercise of ‘‘judgment’’ as to whether apollutant could ‘‘reasonably be anticipatedto endanger public health or welfare,’’S 498§ 7521(a)(1), could be based on scientificuncertainty as well as other factors, includ-ing the concern that unilateral U.S. regula-tion of motor-vehicle emissions couldweaken efforts to reduce other countries’greenhouse gas emissions. The secondjudge opined that petitioners had failed todemonstrate the particularized injury tothem that is necessary to establish stand-ing under Article III, but accepted thecontrary view as the law of the case andjoined the judgment on the merits as the

closest to that which he preferred. Thecourt therefore denied review.

Held:

1. Petitioners have standing to chal-lenge EPA’s denial of their rulemakingpetition. Pp. 1452 – 1458.

(a) This case suffers from none of thedefects that would preclude it from being ajusticiable Article III ‘‘Controvers[y].’’See, e.g., Luther v. Borden, 7 How. 1, 12L.Ed. 581. Moreover, the proper construc-tion of a congressional statute is an emi-nently suitable question for federal-courtresolution, and Congress has authorizedprecisely this type of challenge to EPAaction, see 42 U.S.C. § 7607(b)(1). Con-trary to EPA’s argument, standing doc-trine presents no insuperable jurisdictionalobstacle here. To demonstrate standing, alitigant must show that it has suffered aconcrete and particularized injury that iseither actual or imminent, that the injuryis fairly traceable to the defendant, andthat a favorable decision will likely redressthat injury. See Lujan v. Defenders ofWildlife, 504 U.S. 555, 560–561, 112 S.Ct.2130, 119 L.Ed.2d 351. However, a liti-gant to whom Congress has ‘‘accorded aprocedural right to protect his concreteinterests,’’ id., at 573, n. 7, 112 S.Ct.2130—here, the right to challenge agencyaction unlawfully withheld, § 7607(b)(1)—‘‘can assert that right without meeting allthe normal standards for redressabilityand immediacy,’’ ibid. Only one petitionerneeds to have standing to authorize re-view. See Rumsfeld v. Forum for Aca-demic and Institutional Rights, Inc., 547U.S. 47, 52, n. 2, 126 S.Ct. 1297, 164L.Ed.2d 156. Massachusetts has a specialposition and interest here. It is a sover-eign State and not, as in Lujan, a privateindividual, and it actually owns a greatdeal of the territory alleged to be affected.The sovereign prerogatives to force reduc-tions in greenhouse gas emissions, to nego-


tiate emissions treaties with developingcountries, and (in some circumstances) toexercise the police power to reduce motor-vehicle emissions are now lodged in theFederal Government. Because Congresshas ordered EPA to protect Massachusetts(among others) by prescribing applicablestandards, § 7521(a)(1), and has givenMassachusetts a concomitant proceduralright to challenge the rejection of its rule-making petition as arbitrary and capri-cious, § 7607(b)(1), petitioners’ submis-sions as they pertain to Massachusettshave satisfied the most demanding stan-dards of the adversarial process. EPA’ssteadfast refusal to S 499regulate greenhousegas emissions presents a risk of harm toMassachusetts that is both ‘‘actual’’ and‘‘imminent,’’ Lujan, 504 U.S., at 560, 112S.Ct. 2130, and there is a ‘‘substantial like-lihood that the judicial relief requested’’will prompt EPA to take steps to reducethat risk, Duke Power Co. v. CarolinaEnvironmental Study Group, Inc., 438U.S. 59, 79, 98 S.Ct. 2620, 57 L.Ed.2d 595.Pp. 1452 – 1455.

(b) The harms associated with climatechange are serious and well recognized.The Government’s own objective assess-ment of the relevant science and a strongconsensus among qualified experts indicatethat global warming threatens, inter alia,a precipitate rise in sea levels, severe andirreversible changes to natural ecosystems,a significant reduction in winter snowpackwith direct and important economic conse-quences, and increases in the spread ofdisease and the ferocity of weather events.That these changes are widely shared doesnot minimize Massachusetts’ interest inthe outcome of this litigation. See FederalElection Comm’n v. Akins, 524 U.S. 11, 24,118 S.Ct. 1777, 141 L.Ed.2d 10. Accordingto petitioners’ uncontested affidavits, glob-al sea levels rose between 10 and 20 cen-timeters over the 20th century as a resultof global warming and have already begun

to swallow Massachusetts’ coastal land.Remediation costs alone, moreover, couldreach hundreds of millions of dollars. Pp.1454 – 1456.

(c) Given EPA’s failure to dispute theexistence of a causal connection betweenmanmade greenhouse gas emissions andglobal warming, its refusal to regulatesuch emissions, at a minimum, ‘‘contrib-utes’’ to Massachusetts’ injuries. EPAoverstates its case in arguing that its deci-sion not to regulate contributes so insignif-icantly to petitioners’ injuries that it can-not be haled into federal court, and thatthere is no realistic possibility that therelief sought would mitigate global climatechange and remedy petitioners’ injuries,especially since predicted increases inemissions from China, India, and otherdeveloping nations will likely offset anymarginal domestic decrease EPA regula-tion could bring about. Agencies, like leg-islatures, do not generally resolve massiveproblems in one fell swoop, see William-son v. Lee Optical of Okla., Inc., 348 U.S.483, 489, 75 S.Ct. 461, 99 L.Ed. 563, butinstead whittle away over time, refiningtheir approach as circumstances changeand they develop a more nuanced under-standing of how best to proceed, cf. SECv. Chenery Corp., 332 U.S. 194, 202–203, 67S.Ct. 1575, 91 L.Ed. 1995. That a firststep might be tentative does not by itselfnegate federal-court jurisdiction. And re-ducing domestic automobile emissions ishardly tentative. Leaving aside the othergreenhouse gases, the record indicatesthat the U.S. transportation sector emitsan enormous quantity of carbon dioxideinto the atmosphere. Pp. 1456 – 1457.

(d) While regulating motor-vehicleemissions may not by itself reverse globalwarming, it does not follow that the Courtlacks jurisdiction to decide whether EPAhas a duty to take steps to slow or reduceit. S 500See Larson v. Valente, 456 U.S. 228,


549 U.S. 501

243, n. 15, 102 S.Ct. 1673, 72 L.Ed.2d 33.Because of the enormous potential conse-quences, the fact that a remedy’s effective-ness might be delayed during the (relative-ly short) time it takes for a new motor-vehicle fleet to replace an older one isessentially irrelevant. Nor is it dispositivethat developing countries are poised tosubstantially increase greenhouse gasemissions: A reduction in domestic emis-sions would slow the pace of global emis-sions increases, no matter what happenselsewhere. The Court attaches considera-ble significance to EPA’s espoused beliefthat global climate change must be ad-dressed. Pp. 1457 – 1458.

2. The scope of the Court’s review ofthe merits of the statutory issues is nar-row. Although an agency’s refusal to initi-ate enforcement proceedings is not ordi-narily subject to judicial review, Heckler v.Chaney, 470 U.S. 821, 105 S.Ct. 1649, 84L.Ed.2d 714, there are key differences be-tween nonenforcement and denials of rule-making petitions that are, as in the pres-ent circumstances, expressly authorized.EPA concluded alternatively in its petitiondenial that it lacked authority under§ 7521(a)(1) to regulate new vehicle emis-sions because carbon dioxide is not an ‘‘airpollutant’’ under § 7602, and that, even ifit possessed authority, it would decline toexercise it because regulation would con-flict with other administration priorities.Because the Act expressly permits reviewof such an action, § 7607(b)(1), this Court‘‘may reverse [it if it finds it to be] arbi-trary, capricious, an abuse of discretion, orotherwise not in accordance with law,’’§ 7607(d)(9). Pp. 1459 – 1460.

3. Because greenhouse gases fit wellwithin the Act’s capacious definition of ‘‘airpollutant,’’ EPA has statutory authority toregulate emission of such gases from newmotor vehicles. That definition—which in-cludes ‘‘any air pollution agent TTT, includ-ing any physical, chemical, TTT substance

TTT emitted into TTT the ambient air TTT,’’§ 7602(g) (emphasis added)—embraces allairborne compounds of whatever stripe.Moreover, carbon dioxide and other green-house gases are undoubtedly ‘‘physical[and] chemical TTT substance[s].’’ Ibid.EPA’s reliance on postenactment congres-sional actions and deliberations it views astantamount to a command to refrain fromregulating greenhouse gas emissions isunavailing. Even if postenactment legisla-tive history could shed light on the mean-ing of an otherwise-unambiguous statute,EPA identifies nothing suggesting thatCongress meant to curtail EPA’s power totreat greenhouse gases as air pollutants.The Court has no difficulty reconcilingCongress’ various efforts to promote inter-agency collaboration and research to bet-ter understand climate change with theAgency’s pre-existing mandate to regulate‘‘any air pollutant’’ that may endanger thepublic welfare. FDA v. Brown & Wil-liamson Tobacco Corp., 529 U.S. 120, 133,120 S.Ct. 1291, 146 L.Ed.2d 121, distin-guished. Also unperSsuasive501 is EPA’sargument that its regulation of motor-vehi-cle carbon dioxide emissions would requireit to tighten mileage standards, a job (ac-cording to EPA) that Congress has as-signed to the Department of Transporta-tion. The fact that DOT’s mandate topromote energy efficiency by setting mile-age standards may overlap with EPA’senvironmental responsibilities in no waylicenses EPA to shirk its duty to protectthe public ‘‘health’’ and ‘‘welfare,’’§ 7521(a)(1). Pp. 1459 – 1462.

4. EPA’s alternative basis for its de-cision—that even if it has statutory au-thority to regulate greenhouse gases, itwould be unwise to do so at this time—rests on reasoning divorced from the stat-utory text. While the statute conditionsEPA action on its formation of a ‘‘judg-ment,’’ that judgment must relate to


whether an air pollutant ‘‘cause[s], or con-tribute[s] to, air pollution which may rea-sonably be anticipated to endanger publichealth or welfare.’’ § 7601(a)(1). Underthe Act’s clear terms, EPA can avoid pro-mulgating regulations only if it determinesthat greenhouse gases do not contribute toclimate change or if it provides some rea-sonable explanation as to why it cannot orwill not exercise its discretion to deter-mine whether they do. It has refused todo so, offering instead a laundry list ofreasons not to regulate, including the exis-tence of voluntary Executive Branch pro-grams providing a response to globalwarming and impairment of the Presi-dent’s ability to negotiate with developingnations to reduce emissions. These policyjudgments have nothing to do with wheth-er greenhouse gas emissions contribute toclimate change and do not amount to areasoned justification for declining to forma scientific judgment. Nor can EPA avoidits statutory obligation by noting the un-certainty surrounding various features ofclimate change and concluding that itwould therefore be better not to regulateat this time. If the scientific uncertaintyis so profound that it precludes EPA frommaking a reasoned judgment, it must sayso. The statutory question is whether suf-ficient information exists for it to make anendangerment finding. Instead, EPA re-jected the rulemaking petition based onimpermissible considerations. Its actionwas therefore ‘‘arbitrary, capricious, orotherwise not in accordance with law,’’§ 7607(d)(9). On remand, EPA mustground its reasons for action or inaction inthe statute. Pp. 1462 – 1463.

415 F.3d 50, reversed and remanded.

STEVENS, J., delivered the opinionof the Court, in which KENNEDY,SOUTER, GINSBURG, and BREYER,JJ., joined. ROBERTS, C.J., filed adissenting opinion, in which SCALIA,THOMAS, and ALITO, JJ., joined, post, p.

1463. SCALIA, J., filed a dissentingopinion, in which ROBERTS, C.J., andTHOMAS and ALITO, JJ., joined, post, p.1471.

James R. Milkey, Boston, MA, for peti-tioners.

Gregory G. Garre, Washington, D.C., forrespondents.

Thomas F. Reilly, Attorney General ofMassachusetts, Lisa Heinzerling, SpecialAssistant Attorney General, Washington,D.C., James R. Milkey, Counsel of Record,William L. Pardee, Carol Iancu, AssistantAttorneys General, Boston, MA, Bill Lock-yer, Attorney General of California, MarcN. Melnick, Nicholas Stern, Deputy Attor-neys General, Oakland, CA, Richard Blu-menthal, Attorney General of Connecticut,Kimberly Massicotte, Matthew Levin, As-sistant Attorneys General, Hartford, CT,Lisa Madigan, Attorney General of Illinois,Matthew J. Dunn, Gerald T. Karr, Assis-tant Attorneys General, Chicago, IL, G.Steven Rowe, Attorney General of Maine,Gerald D. Reid, Assistant Attorney Gener-al, Augusta, ME, Stuart Rabner, AttorneyGeneral of New Jersey, Stefanie A. Brand,Kevin P. Auerbacher, Lisa Morelli, DeputyAttorneys General, Trenton, NJ, PatriciaA. Madrid, Attorney General of New Mexi-co, Stuart M. Bluestone, Deputy AttorneyGeneral, Stephen R. Ferris, Judith AnnMoore, Assistant Attorneys General, SanteFe, NM, Eliot Spitzer, Attorney General ofNew York, Caitlin J. Halligan, SolicitorGeneral, J. Jared Snyder, Assistant Attor-neys General, New York, NY, HardyMyers Attorney General of Oregon, PhilipSchradle, Special Counsel to the AttorneyGeneral, Richard Whitman, Assistant At-torney General, Oregon Dept. of Justice,Salem, OR, Patrick C. Lynch, AttorneyGeneral of Rhode Island, Tricia K. Jedele,Special Assistant Attorney General, Provi-dence, RI, William H. Sorrell, Attorney


549 U.S. 501

General of Vermont, Kevin O. Leske, As-sistant Attorney General, Montpelier, VT,Rob McKenna, Attorney General of Wash-ington, Leslie R. Seffern, Assistant Attor-ney General, Jay D. Geck, Deputy SolicitorGeneral, Olympia, WA, Robert J. Spagno-letti, Attorney General of the District ofColumbia, Todd S. Kim, Solicitor General,Donna Murasky, Senior Assistant Attor-ney General, South Washington, D.C., Ma-laetasi M. Togafau, Attorney General ofAmerican Samoa, Pago Pago, AmericanSamoa, Michael Cardozo, CorporationCounsel, City of New York, Susan KathScott Pasternack, Tracy Triplett, AssistantCorporation Counsel, New York, NY,Ralph S. Tyler, City Solicitor, City of Bal-timore, William Phelan, Jr., PrincipalCounsel, Baltimore City Dept. of Law, Bal-timore, MD, Julie Teel, San Diego, CA,Counsel for Center for Biological Diversi-ty, Joseph Mendelson III, Washington,DC, Counsel for International Center forTechnology Assessment, Center for FoodSafety, Environmental Advocates, andGreenpeace, Seth Kaplan, Boston, MA,Counsel for Conservation Law Foundation,James B. Tripp, New York, NY, Counselfor Environmental Defense, Brian Dunkiel,Shems Dunkiel Kassel & Saunders PLLC,Burlington, Vermont, Danielle Fugere, SanFrancisco, CA, Counsel for Friends of theEarth, John M. Stanton, Washington, DC,Counsel for National Environmental Trust,David Doniger, Washington, DC, Counselfor Natural Resources Defense Council,David Bookbinder, Washington, DC, How-ard Fox, Washington, DC, Counsel for Si-erra Club, Alexandra Schulte, Washington,DC, Counsel for Union of Concerned Sci-entists, Alex Fidis, Washington, DC, Coun-sel for U.S. Public Interest ResearchGroup, for Petitioners.

Kenneth W. Starr, Stuart A.C. Drake,Andrew B. Clubok, Ashley C. Parrish,Derek S. Bentsen, Kirkland & Ellis LLP,Washington, D.C., Richard A. Cordray,

Grove City, Ohio, Theodore B. Olson,Counsel of Record, Miguel A. Estrada,David Debold, Matthew D. McGill, AmirTayrani, Gibson, Dunn & Crutcher LLP,Washington, D.C., for Respondents.

Norman W. Fichthorn, Counsel of Rec-ord, Allison D. Wood, Hunton & WilliamsLLP, Washington, D.C. for RespondentUtility Air Regulatory Group.

Russell S. Frye, FryeLaw PLLC, Wash-ington, DC, Counsel of Record for Inter-venor-Respondent CO2 Litigation Group,Of Counsel: Dell E. Perelman, Vice Presi-dent and General Counsel, Leslie A.Hulse, Assistant General Counsel, Ameri-can Chemistry Council, Arlington, VA,Richard Wasserstrom, American Forest &Paper Association, Washington, DC, Har-ry M. Ng, General Counsel, Ralph J.Colleli, Jr., American Petroleum Institute,Washington, DC, Nick Goldstein, Staff At-torney, American Road and Transporta-tion Builders Association, Washington,DC, Jan S. Amundson, Senior Vice Presi-dent & General Counsel, Quentin Riegel,Vice President, Litigation & Deputy Gen-eral Counsel, National Association of Man-ufacturers, Washington, DC, Robin S.Conrad, National Chamber Litigation Cen-ter, Inc., Washington, DC, Bob Slaughter,President & General Counsel, NationalPetrochemical & Refiners Association,Washington, DC, John L. Wittenborn,Kelley Drye, Collier Shannon, Washing-ton, DC, for Respondent CO2 LitigationGroup.

Roger R. Martella, Jr., Acting GeneralCounsel, Carol S. Holmes, Attorney, Envi-ronmental Protection Agency, Washington,D.C., Paul D. Clement, Solicitor General,Counsel of Record, Sue Ellen Wooldridge,Assistant Attorney General, Gregory G.Garre, Thomas G. Hungar, Deputy Solici-tors General, Malcolm L. Stewart, Assis-tant to the Solicitor General, Jon M. Lip-


shultz, Attorney, Department of Justice,Washington, D.C., for Federal Respon-dent.

Michael A. Cox, Michigan Attorney Gen-eral, Thomas L. Casey, Michigan SolicitorGeneral, Counsel of Record, Lansing, MI,Alan F. Hoffman, Neil D. Gordon, Assis-tant Attorneys General, for the State ofMichigan, for the State of Texas, GregAbbott, Attorney General, Karen W. Kor-nell, Assistant Attorney General, Chief,Natural Resources Division, Jane Atwood,Assistant Attorney General, Austin, Texas,for the State of Ohio, Jim Petro, AttorneyGeneral, Dale T. Vitale, Senior Deputy,Attorney General, Environmental Enforce-ment Section, Columbus, Ohio, for respon-dent states of Michigan, North Dakota,Utah, South Dakota, Alaska, Kansas, Ne-braska, Texas, and Ohio.

For U.S. Supreme Court briefs, see:

2006 WL 2563378 (Pet.Brief)

2006 WL 3023028 (Resp.Brief)

2006 WL 3101955 (Resp.Brief)

2006 WL 3043971 (Resp.Brief)

2006 WL 3043970 (Resp.Brief)

2006 WL 3095443 (Resp.Brief)

2006 WL 3367871 (Reply.Brief)

Justice STEVENS delivered the opinionof the Court.

S 504A well-documented rise in globaltemperatures has coincided with a signifi-

cant increase in the concentration ofcarSbon505 dioxide in the atmosphere. Re-spected scientists believe the two trendsare related. For when carbon dioxide isreleased into the atmosphere, it acts likethe ceiling of a greenhouse, trapping solarenergy and retarding the escape of re-flected heat. It is therefore a species—themost important species—of a ‘‘greenhousegas.’’

Calling global warming ‘‘the most press-ing environmental challenge of our time,’’ 1

a group of States,2 local governments,3 andprivate organizations4 alleged in a petitionfor certiorari that the Environmental Pro-tection Agency (EPA) has abdicated itsresponsibility under the Clean Air Act toregulate the emissions of four greenhousegases, including carbon dioxide. Specifi-cally, petitioners asked us to answer twoquestions concerning the meaning of§ 202(a)(1) of the Act: whether EPA hasthe statutory authority to regulate green-house gas emissions from new motor vehi-cles; and if so, whether its stated reasonsfor refusing to do so are consistent withthe statute.

In response, EPA, supported by 10 in-tervening States 5 and six trade associa-tions,6 correctly argued that we may notaddress those two questions unless at leastone petitioner has standing to invoke ourjurisdiction under Article III of the Consti-

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 forFood Safety, Conservation Law Foundation,Environmental Advocates, Environmental De-fense, Friends of the Earth, Greenpeace, In-ternational Center for Technology Assess-ment, National Environmental Trust, Natural

Resources Defense Council, Sierra Club, Un-ion of Concerned Scientists, and U.S. PublicInterest Research Group.

5. Alaska, Idaho, Kansas, Michigan, Nebraska,North Dakota, Ohio, South Dakota, Texas,and Utah.

6. Alliance of Automobile Manufacturers, Na-tional Automobile Dealers Association, En-gine Manufacturers Association, Truck Manu-facturers Association, CO2 Litigation Group,and Utility Air Regulatory Group.


549 U.S. 507

tution. Notwithstanding the serious char-acter of S 506that jurisdictional argumentand the absence of any conflicting deci-sions construing § 202(a)(1), the unusualimportance of the underlying issue per-suaded us to grant the writ. 548 U.S. 903,126 S.Ct. 2960, 165 L.Ed.2d 949 (2006).

I

Section 202(a)(1) of the Clean Air Act,as added by Pub.L. 89–272, § 101(8), 79Stat. 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 byregulation prescribe (and from time totime revise) in accordance with the pro-visions of this section, standards applica-ble to the emission of any air pollutantfrom any class or classes of new motorvehicles or new motor vehicle engines,which in his judgment cause, or contrib-ute to, air pollution which may reason-

ably be anticipated to endanger publichealth or welfare TTT.’’ 7

The Act defines ‘‘air pollutant’’ to include‘‘any air pollution agent or combination ofsuch agents, including any physical, chemi-cal, biological, radioactive TTT substance ormatter which is emitted into or otherwiseenters the ambient air.’’ § 7602(g). ‘‘Wel-fare’’ is also defined broadly: among otherthings, it includes ‘‘effects on TTT weatherTTT and climate.’’ § 7602(h).

S 507When Congress enacted these provi-sions, the study of climate change was inits infancy.8 In 1959, shortly after theU.S. Weather Bureau began monitoringatmospheric carbon dioxide levels, an ob-servatory in Mauna Loa, Hawaii, recordeda mean level of 316 parts per million. Thiswas well above the highest carbon dioxideconcentration—no more than 300 parts permillion—revealed in the 420,000–year–oldice-core record.9 By the time Congressdrafted § 202(a)(1) in 1970, carbon dioxidelevels had reached 325 parts per million.10

7. The 1970 version of § 202(a)(1) used thephrase ‘‘which endangers the public health orwelfare’’ rather than the more protective‘‘which may reasonably be anticipated to en-danger public health or welfare.’’ See § 6(a)of the Clean Air Amendments of 1970, 84Stat. 1690. Congress amended § 202(a)(1) in1977 to give its approval to the decision inEthyl Corp. v. EPA, 541 F.2d 1, 25 (C.A.D.C.1976) (en banc), which held that the Clean AirAct ‘‘and common sense TTT demand regula-tory action to prevent harm, even if the regu-lator is less than certain that harm is other-wise inevitable.’’ See § 401(d)(1) of theClean Air Act Amendments of 1977, 91 Stat.791; see also H.R.Rep. No. 95–294, p. 49(1977), U.S. Code Cong. & Admin.News 1977,p. 1077.

8. The Council on Environmental Quality hadissued a report in 1970 concluding that‘‘[m]an may be changing his weather.’’ Envi-ronmental Quality: The First Annual Report93. Considerable uncertainty remained inthose early years, and the issue went largelyunmentioned in the congressional debate overthe enactment of the Clean Air Act. But see116 Cong. Rec. 32914 (1970) (statement of

Sen. Boggs referring to Council’s conclusionthat ‘‘[a]ir pollution alters the climate andmay produce global changes in tempera-ture’’).

9. See Intergovernmental Panel on ClimateChange, Climate Change 2001: Synthesis Re-port, pp. 202–203 (2001). By drilling throughthick Antarctic ice sheets and extracting‘‘cores,’’ scientists can examine ice from longago and extract small samples of ancient air.That air can then be analyzed, yielding esti-mates of carbon dioxide levels. Ibid.

10. A more dramatic rise was yet to come: In2006, carbon dioxide levels reached 382 partsper million, see Dept. of Commerce, NationalOceanic & Atmospheric Administration, Mau-na Loa CO2 Monthly Mean Data, http://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 casefile), a level thought to exceed the concentra-tion of carbon dioxide in the atmosphere atany point over the past 20 million years. SeeIntergovernmental Panel on Climate Change,Technical Summary of Working Group I Re-port 39 (2001).


In the late 1970’s, the Federal Govern-ment began devoting serious attention tothe possibility that carbon dioxide emis-sions associated with human activity couldprovoke climate change. In 1978, Con-gress enacted the National Climate Pro-gram Act, 92 Stat. 601, which required thePresident to establish a program to ‘‘assistthe Nation and the world to S 508understandand respond to natural and man-inducedclimate processes and their implications,’’id., § 3. President Carter, in turn, askedthe National Research Council, the work-ing arm of the National Academy of Sci-ences, to investigate the subject. TheCouncil’s response was unequivocal: ‘‘Ifcarbon dioxide continues to increase, thestudy group finds no reason to doubt thatclimate changes will result and no reasonto believe that these changes will be negli-gible TTT. A wait-and-see policy may meanwaiting until it is too late.’’ 11

Congress next addressed the issue in1987, when it enacted the Global ClimateProtection Act, Title XI of Pub.L. 100–204,101 Stat. 1407, note following 15 U.S.C.§ 2901. Finding that ‘‘manmade pollu-tion—the release of carbon dioxide, chloro-fluorocarbons, methane, and other tracegases into the atmosphere—may be pro-ducing a long-term and substantial in-crease in the average temperature onEarth,’’ § 1102(1), 101 Stat. 1408, Con-gress directed EPA to propose to Con-gress a ‘‘coordinated national policy onglobal climate change,’’ § 1103(b), and or-dered the Secretary of State to work‘‘through the channels of multilateral diplo-macy’’ and coordinate diplomatic efforts to

combat global warming, § 1103(c). Con-gress emphasized that ‘‘ongoing pollutionand deforestation may be contributing nowto an irreversible process’’ and that ‘‘[n]ec-essary actions must be identified and im-plemented in time to protect the climate.’’§ 1102(4).

Meanwhile, the scientific understandingof climate change progressed. In 1990,the Intergovernmental Panel on ClimateChange (IPCC), a multinational scientificbody organized under the auspices of theUnited Nations, published its first compre-hensive report on the topic. Drawing onexpert opinions from across the globe, theIPCC concluded that ‘‘emissions resultingfrom human activities are substantiallyS 509increasing the atmospheric concentra-tions of TTT greenhouse gases [which] willenhance the greenhouse effect, resultingon average in an additional warming of theEarth’s surface.’’ 12

Responding to the IPCC report, theUnited Nations convened the ‘‘Earth Sum-mit’’ in 1992 in Rio de Janeiro. The firstPresident Bush attended and signed theUnited Nations Framework Convention onClimate Change (UNFCCC), a nonbindingagreement among 154 nations to reduceatmospheric concentrations of carbon diox-ide and other greenhouse gases for thepurpose of ‘‘prevent[ing] dangerous an-thropogenic [i.e., human-induced] interfer-ence with the [Earth’s] climate system.’’ 13

S. Treaty Doc. No. 102–38, Art. 2, p. 5,1771 U.N.T.S. 107 (1992). The Senateunanimously ratified the treaty.

11. Climate Research Board, Carbon Dioxideand Climate: A Scientific Assessment, p. viii(1979).

12. IPCC, Climate Change: The IPCC Scienti-fic Assessment, p. xi (J. Houghton, G. Jenkins,& J. Ephraums eds.1991).

13. The industrialized countries listed in AnnexI to the UNFCCC undertook to reduce their

emissions of greenhouse gases to 1990 levelsby the year 2000. No immediate restrictionswere imposed on developing countries, in-cluding China and India. They could chooseto become Annex I countries when sufficientlydeveloped.


549 U.S. 511

Some five years later—after the IPCCissued a second comprehensive report in1995 concluding that ‘‘[t]he balance of evi-dence suggests there is a discernible hu-man influence on global climate’’ 14—theUNFCCC signatories met in Kyoto, Ja-pan, and adopted a protocol that assignedmandatory targets for industrialized na-tions to reduce greenhouse gas emissions.Because those targets did not apply todeveloping and heavily polluting nationssuch as China and India, the Senate unani-mously passed a resolution expressing itssense that the United States should notenter into the Kyoto Protocol. See S. Res.98, 105th Cong., 1st Sess. (July 25, 1997)(as passed). President Clinton did notsubmit the protocol to the Senate for rati-fication.

S 510II

On October 20, 1999, a group of 19 pri-vate organizations 15 filed a rulemaking pe-tition asking EPA to regulate ‘‘greenhousegas emissions from new motor vehiclesunder § 202 of the Clean Air Act.’’ App. 5.Petitioners maintained that 1998 was the‘‘warmest year on record’’; that carbondioxide, methane, nitrous oxide, and hydro-fluorocarbons are ‘‘heat trapping green-house gases’’; that greenhouse gas emis-sions have significantly accelerated climatechange; and that the IPCC’s 1995 reportwarned that ‘‘carbon dioxide remains themost important contributor to [manmade]forcing of climate change.’’ Id., at 13 (in-ternal quotation marks omitted). The pe-tition further alleged that climate change

will have serious adverse effects on humanhealth and the environment. Id., at 22–35.As to EPA’s statutory authority, the peti-tion observed that the Agency itself hadalready confirmed that it had the power toregulate carbon dioxide. See id., at 18, n.21. In 1998, Jonathan Z. Cannon, thenEPA’s general counsel, prepared a legalopinion concluding that ‘‘CO2 emissions arewithin the scope of EPA’s authority toregulate,’’ even as he recognized that EPAhad so far declined to exercise that author-ity. Id., at 54 (memorandum to Carol M.Browner, Administrator (Apr. 10, 1998)(hereinafter Cannon memorandum)).Cannon’s successor, Gary S. Guzy, reiter-ated that opinion before a congressionalcommittee just S 511two weeks before therulemaking petition was filed. See id., at61.

Fifteen months after the petition’s sub-mission, EPA requested public commenton ‘‘all the issues raised in [the] petition,’’adding a ‘‘particular’’ request for com-ments on ‘‘any scientific, technical, legal,economic or other aspect of these issuesthat may be relevant to EPA’s consider-ation 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 inidentifying the areas in the science of cli-mate change where there are the greatestcertainties and uncertainties’’ from the Na-tional Research Council, asking for a re-sponse ‘‘as soon as possible.’’ App. 213.

14. IPCC, Climate Change 1995, The Scienceof Climate Change, p. 4.

15. Alliance for Sustainable Communities; Ap-plied Power Technologies, Inc.; Bio FuelsAmerica; The California Solar Energy Indus-tries Assn.; Clements Environmental Corp.;Environmental Advocates; Environmentaland Energy Study Institute; Friends of theEarth; Full Circle Energy Project, Inc.; The

Green Party of Rhode Island; GreenpeaceUSA; International Center for Technology As-sessment; Network for Environmental andEconomic Responsibility of the UnitedChurch of Christ; New Jersey EnvironmentalWatch; New Mexico Solar Energy Assn.; Or-egon Environmental Council; Public Citizen;Solar Energy Industries Assn.; The SUN DAYCampaign. See App. 7–11.


The result was a 2001 report titled ClimateChange Science: An Analysis of Some KeyQuestions (NRC Report), which, drawingheavily on the 1995 IPCC report, conclud-ed that ‘‘[g]reenhouse gases are accumulat-ing in Earth’s atmosphere as a result ofhuman activities, causing surface air temp-eratures and subsurface ocean tempera-tures to rise. Temperatures are, in fact,rising.’’ NRC Report 1.

On September 8, 2003, EPA entered anorder denying the rulemaking petition. 68Fed.Reg. 52922. The Agency gave tworeasons for its decision: (1) that contraryto the opinions of its former general coun-sels, the Clean Air Act does not authorizeEPA to issue mandatory regulations toaddress global climate change, see id., at52925–52929; and (2) that even if theAgency had the authority to set green-house gas emission standards, it would beunwise to do so at this time, id., at 52929–52931.

In concluding that it lacked statutoryauthority over greenhouse gases, EPA ob-served that Congress ‘‘was well aware ofthe global climate change issue when itlast comprehensively amended the [CleanAir Act] in 1990,’’ yet it declined to adopt aproposed amendment establishing bindingS 512emissions limitations. Id., at 52926.Congress instead chose to authorize fur-ther investigation into climate change.Ibid. (citing §§ 103(g) and 602(e) of theClean Air Act Amendments of 1990, 104Stat. 2652, 2703, 42 U.S.C. §§ 7403(g)(1)and 7671a(e)). EPA further reasoned thatCongress’ ‘‘specially tailored solutions toglobal atmospheric issues,’’ 68 Fed.Reg.52926—in particular, its 1990 enactment ofa comprehensive scheme to regulate pollu-tants that depleted the ozone layer, seeTitle VI, 104 Stat. 2649, 42 U.S.C.§§ 7671–7671q—counseled against readingthe general authorization of § 202(a)(1) to

confer regulatory authority over green-house gases.

EPA stated that it was ‘‘urged on in thisview,’’ 68 Fed.Reg. 529 by this Court’sdecision in FDA v. Brown & WilliamsonTobacco Corp., 529 U.S. 120, 120 S.Ct.1291, 146 L.Ed.2d 121 (2000). In thatcase, relying on ‘‘tobacco[’s] unique politi-cal history,’’ id., at 159, 120 S.Ct. 1291, weinvalidated the Food and Drug Adminis-tration’s reliance on its general authorityto regulate drugs as a basis for assertingjurisdiction over an ‘‘industry constitutinga significant portion of the American econ-omy,’’ ibid.

EPA reasoned that climate change hadits own ‘‘political history’’: Congress de-signed the original Clean Air Act to ad-dress local air pollutants rather than asubstance that ‘‘is fairly consistent in itsconcentration throughout the world’s at-mosphere,’’ 68 Fed.Reg. 52927; declined in1990 to enact proposed amendments toforce EPA to set carbon dioxide emissionstandards for motor vehicles, ibid. (citingH.R. 5966, 101st Cong., 2d Sess. (1990));and addressed global climate change inother legislation, 68 Fed.Reg. 52927. Be-cause of this political history, and becauseimposing emission limitations on green-house gases would have even greater eco-nomic and political repercussions than reg-ulating tobacco, EPA was persuaded thatit lacked the power to do so. Id., at 52928.In essence, EPA concluded that climatechange was so important that unless Con-gress spoke with exacting specificity, itcould not have meant the Agency to ad-dress it.

S 513Having reached that conclusion, EPAbelieved it followed that greenhouse gasescannot be ‘‘air pollutants’’ within the mean-ing of the Act. See ibid. (‘‘It follows fromthis conclusion, that [greenhouse gases], assuch, are not air pollutants under the[Clean Air Act’s] regulatory provisionsTTT’’). The Agency bolstered this conclu-


549 U.S. 514

sion by explaining that if carbon dioxidewere an air pollutant, the only feasiblemethod of reducing tailpipe emissionswould be to improve fuel economy. Butbecause Congress has already created de-tailed mandatory fuel economy standardssubject to Department of Transportation(DOT) administration, the Agency conclud-ed that EPA regulation would either con-flict with those standards or be superflu-ous. Id., at 52929.

Even assuming that it had authorityover greenhouse gases, EPA explained indetail why it would refuse to exercise thatauthority. The Agency began by recogniz-ing that the concentration of greenhousegases has dramatically increased as a re-sult of human activities, and acknowledgedthe attendant increase in global surface airtemperatures. Id., at 52930. EPA never-theless gave controlling importance to theNRC Report’s statement that a causal linkbetween the two ‘‘ ‘cannot be unequivocallyestablished.’ ’’ Ibid. (quoting NRC Report17). Given that residual uncertainty, EPAconcluded that regulating greenhouse gasemissions would be unwise. 68 Fed.Reg.52930.

The Agency furthermore characterizedany EPA regulation of motor-vehicleemissions as a ‘‘piecemeal approach’’ toclimate change, id., at 52931, and statedthat such regulation would conflict withthe President’s ‘‘comprehensive approach’’to the problem, ibid. That approach in-volves additional support for technologicalinnovation, the creation of nonregulatoryprograms to encourage voluntary private-sector reductions in greenhouse gas emis-sions, and further research on climatechange—not actual regulation. Id., at52932–52933. According to EPA, unilat-

eral EPA regulation of motor-vehiclegreenhouse gas emissions might alsoS 514hamper the President’s ability to per-suade key developing countries to reducegreenhouse gas emissions. Id., at 52931.

III

Petitioners, now joined by intervenorStates and local governments, sought re-view of EPA’s order in the United StatesCourt of Appeals for the District of Co-lumbia Circuit.16 Although each of thethree judges on the panel wrote a separateopinion, two judges agreed ‘‘that the EPAAdministrator properly exercised his dis-cretion under § 202(a)(1) in denying thepetition for rule making.’’ 415 F.3d 50, 58(2005). The court therefore denied thepetition for review.

In his opinion announcing the court’sjudgment, Judge Randolph avoided a de-finitive ruling as to petitioners’ standing,id., at 56, reasoning that it was permissibleto proceed to the merits because thestanding and the merits inquiries ‘‘over-lap[ped],’’ ibid. Assuming without decid-ing that the statute authorized the EPAAdministrator to regulate greenhouse gasemissions that ‘‘in his judgment’’ may ‘‘rea-sonably be anticipated to endanger publichealth or welfare,’’ 42 U.S.C. § 7521(a)(1),Judge Randolph concluded that the exer-cise of that judgment need not be basedsolely on scientific evidence, but may alsobe informed by the sort of policy judg-ments that motivate congressional action.415 F.3d, at 58. Given that framework, itwas reasonable for EPA to base its deci-sion on scientific uncertainty as well as onother factors, including the concern thatunilateral regulation of U.S. motor-vehicleemissions could weaken efforts to reduce

16. See 42 U.S.C. § 7607(b)(1) (‘‘A petition forreview of action of the Administrator in pro-mulgating any TTT standard under section7521 of this title TTT or final action taken, by

the Administrator under this chapter may befiled only in the United States Court of Ap-peals for the District of Columbia’’).


greenhouse gas emissions from other coun-tries. Ibid.

Judge Sentelle wrote separately becausehe believed petitioners failed to ‘‘demons-trat[e] the element of injury necesSsary515

to establish standing under Article III.’’Id., at 59 (opinion dissenting in part andconcurring in judgment). In his view, theyhad alleged that global warming is ‘‘harm-ful to humanity at large,’’ but could notallege ‘‘particularized injuries’’ to them-selves. Id., at 60 (citing Lujan v. Defend-ers of Wildlife, 504 U.S. 555, 562, 112 S.Ct.2130, 119 L.Ed.2d 351 (1992)). While hedissented on standing, however, he accept-ed the contrary view as the law of the caseand joined Judge Randolph’s judgment onthe merits as the closest to that which hepreferred. 415 F.3d, at 60–61.

Judge Tatel dissented. Emphasizingthat EPA nowhere challenged the factualbasis of petitioners’ affidavits, id., at 66, heconcluded that at least Massachusetts had‘‘satisfied each element of Article IIIstanding—injury, causation, and redressa-bility,’’ id., at 64. In Judge Tatel’s view,the ‘‘ ‘substantial probability,’ ’’ id., at 66,that projected rises in sea level would leadto serious loss of coastal property was a‘‘far cry’’ from the kind of generalizedharm insufficient to ground Article III ju-risdiction. Id., at 65. He found that peti-tioners’ affidavits more than adequatelysupported the conclusion that EPA’s fail-ure to curb greenhouse gas emissions con-tributed to the sea level changes thatthreatened Massachusetts’ coastal proper-ty. Ibid. As to redressability, he observedthat one of petitioners’ experts, a formerEPA climatologist, stated that ‘‘ ‘[a]chiev-able reductions in emissions of CO2 andother [greenhouse gases] from U.S. motorvehicles would TTT delay and moderatemany of the adverse impacts of globalwarming.’ ’’ Ibid. (quoting declaration ofMichael MacCracken, former Executive

Director, U.S. Global Change ResearchProgram ¶ 5(e) (hereinafter MacCrackenDecl.), available in 2 Petitioners’ StandingAppendix in No. 03–1361 etc. (CADC), p.209 (Stdg.App.)). He further noted thatthe one-time director of EPA’s motor-vehi-cle pollution control efforts stated in anaffidavit that enforceable emission stan-dards would lead to the development ofnew technologies that ‘‘ ‘would graduallybe mandated by other countries aroundS 516the world.’ ’’ 415 F.3d, at 66 (quotingdeclaration of Michael Walsh ¶¶ 7–8, 10,Stdg.App. 309–310, 311). On the merits,Judge Tatel explained at length why hebelieved the text of the statute providedEPA with authority to regulate green-house gas emissions, and why its policyconcerns did not justify its refusal to exer-cise that authority. 415 F.3d, at 67–82.

IV

Article III of the Constitution limits fed-eral-court jurisdiction to ‘‘Cases’’ and‘‘Controversies.’’ Those two words confine‘‘the business of federal courts to questionspresented in an adversary context and in aform historically viewed as capable of reso-lution through the judicial process.’’ Flastv. Cohen, 392 U.S. 83, 95, 88 S.Ct. 1942, 20L.Ed.2d 947 (1968). It is therefore famil-iar learning that no justiciable ‘‘controver-sy’’ exists when parties seek adjudicationof a political question, Luther v. Borden, 7How. 1, 12 L.Ed. 581 (1849), when theyask for an advisory opinion, Hayburn’sCase, 2 Dall. 409, 1 L.Ed. 436 (1792), seealso Clinton v. Jones, 520 U.S. 681, 700, n.33, 117 S.Ct. 1636, 137 L.Ed.2d 945 (1997),or when the question sought to be adjudi-cated has been mooted by subsequent de-velopments, California v. San Pablo &Tulare R. Co., 149 U.S. 308, 13 S.Ct. 876,37 L.Ed. 747 (1893). This case suffersfrom none of these defects.


549 U.S. 518

The parties’ dispute turns on the properconstruction of a congressional statute, aquestion eminently suitable to resolution infederal court. Congress has moreover au-thorized this type of challenge to EPAaction. See 42 U.S.C. § 7607(b)(1). Thatauthorization is of critical importance tothe standing inquiry: ‘‘Congress has thepower to define injuries and articulatechains of causation that will give rise to acase or controversy where none existedbefore.’’ Lujan, 504 U.S., at 580, 112 S.Ct.2130 (KENNEDY, J., concurring in partand concurring in judgment). ‘‘In exercis-ing this power, however, Congress must atthe very least identify the injury it seeksto vindicate and relate the injury to theclass of persons entitled to bring suit.’’Ibid. We will not, therefore, ‘‘entertaincitiSzen517 suits to vindicate the public’s non-concrete interest in the proper administra-tion of the laws.’’ Id., at 581, 112 S.Ct.2130.

[1] EPA maintains that because green-house gas emissions inflict widespreadharm, the doctrine of standing presents aninsuperable jurisdictional obstacle. We donot agree. At bottom, ‘‘the gist of thequestion of standing’’ is whether petition-ers have ‘‘such a personal stake in theoutcome of the controversy as to assurethat concrete adverseness which sharpensthe presentation of issues upon which thecourt so largely depends for illumination.’’Baker v. Carr, 369 U.S. 186, 204, 82 S.Ct.691, 7 L.Ed.2d 663 (1962). As JusticeKENNEDY explained in his Lujan con-currence:

‘‘While it does not matter how manypersons have been injured by the chal-lenged action, the party bringing suitmust show that the action injures him ina concrete and personal way. This re-quirement is not just an empty formali-ty. It preserves the vitality of the ad-versarial process by assuring both thatthe parties before the court have an

actual, as opposed to professed, stake inthe outcome, and that the legal ques-tions presented TTT will be resolved, notin the rarified atmosphere of a debatingsociety, but in a concrete factual contextconducive to a realistic appreciation ofthe consequences of judicial action.’’504 U.S., at 581, 112 S.Ct. 2130 (internalquotation marks omitted).

[2] To ensure the proper adversarialpresentation, Lujan holds that a litigantmust demonstrate that it has suffered aconcrete and particularized injury that iseither actual or imminent, that the injuryis fairly traceable to the defendant, andthat it is likely that a favorable decisionwill redress that injury. See id., at 560–561, 112 S.Ct. 2130. However, a litigant towhom Congress has ‘‘accorded a procedur-al right to protect his concrete interests,’’id., at 572, n. 7, 112 S.Ct. 2130—here, theright to challenge agency action unlawfullywithheld, § 7607(b)(1)—‘‘can assert thatright without meeting all the normal stan-dards for reSdressability518 and immediacy,’’ibid. When a litigant is vested with aprocedural right, that litigant has standingif there is some possibility that the re-quested relief will prompt the injury-caus-ing party to reconsider the decision thatallegedly harmed the litigant. Ibid.; seealso Sugar Cane Growers Cooperative ofFla. v. Veneman, 289 F.3d 89, 94–95(C.A.D.C.2002) (‘‘A [litigant] who alleges adeprivation of a procedural protection towhich he is entitled never has to provethat if he had received the procedure thesubstantive result would have been al-tered. All that is necessary is to showthat the procedural step was connected tothe substantive result’’).

[3] Only one of the petitioners needs tohave standing to permit us to consider thepetition for review. See Rumsfeld v. Fo-rum for Academic and InstitutionalRights, Inc., 547 U.S. 47, 52, n. 2, 126 S.Ct.


1297, 164 L.Ed.2d 156 (2006). We stresshere, as did Judge Tatel below, the specialposition and interest of Massachusetts. Itis of considerable relevance that the partyseeking review here is a sovereign Stateand not, as it was in Lujan, a privateindividual.

[4] Well before the creation of themodern administrative state, we recog-nized that States are not normal litigantsfor the purposes of invoking federal juris-diction. As Justice Holmes explained inGeorgia v. Tennessee Copper Co., 206 U.S.230, 237, 27 S.Ct. 618, 51 L.Ed. 1038(1907), a case in which Georgia sought toprotect its citizens from air pollution origi-nating outside its borders:

‘‘The case has been argued largely asif it were one between two private par-ties; but it is not. The very elementsthat would be relied upon in a suit be-tween fellow-citizens as a ground forequitable relief are wanting here. TheState owns very little of the territoryalleged to be affected, and the damageto it capable of estimate in money, possi-bly, at least, is small. This is a suit by aState for an injury to it in its capacity ofquasi-sovereign. In that capacity theState has an interest independent of andbehind the titles of its citizens, S 519in allthe earth and air within its domain. Ithas the last word as to whether itsmountains shall be stripped of their for-ests and its inhabitants shall breathepure air.’’

Just as Georgia’s independent interest ‘‘inall the earth and air within its domain’’supported federal jurisdiction a centuryago, so too does Massachusetts’ well-founded desire to preserve its sovereignterritory today. Cf. Alden v. Maine, 527U.S. 706, 715, 119 S.Ct. 2240, 144 L.Ed.2d636 (1999) (observing that in the federalsystem, the States ‘‘are not relegated tothe role of mere provinces or political cor-

porations, but retain the dignity, thoughnot the full authority, of sovereignty’’).That Massachusetts does in fact own agreat deal of the ‘‘territory alleged to beaffected’’ only reinforces the conclusionthat its stake in the outcome of this case issufficiently concrete to warrant the exer-cise of federal judicial power.

When a State enters the Union, it sur-renders certain sovereign prerogatives.Massachusetts cannot invade Rhode Islandto force reductions in greenhouse gasemissions, it cannot negotiate an emissionstreaty with China or India, and in somecircumstances the exercise of its policepowers to reduce in-state motor-vehicleemissions might well be pre-empted. SeeAlfred L. Snapp & Son, Inc. v. PuertoRico ex rel. Barez, 458 U.S. 592, 607, 102S.Ct. 3260, 73 L.Ed.2d 995 (1982) (‘‘Onehelpful indication in determining whetheran alleged injury to the health and welfareof its citizens suffices to give the Statestanding to sue parens patriae is whetherthe injury is one that the State, if it could,would likely attempt to address through itssovereign lawmaking powers’’).

These sovereign prerogatives are nowlodged in the Federal Government, andCongress has ordered EPA to protectMassachusetts (among others) by prescrib-ing standards applicable to the ‘‘emissionof any air pollutant from any class orclasses of new motor vehicle engines,which in [the Administrator’s] judgmentcause, or contribute to, air pollution whichmay reasonably be anticipated to endangerpublic S 520health or welfare.’’ 42 U.S.C.§ 7521(a)(1). Congress has moreover rec-ognized a concomitant procedural right tochallenge the rejection of its rulemakingpetition as arbitrary and capricious.§ 7607(b)(1). Given that procedural rightand Massachusetts’ stake in protecting itsquasi-sovereign interests, the Common-


549 U.S. 521

wealth is entitled to special solicitude inour standing analysis.17

S 521With that in mind, it is clear thatpetitioners’ submissions as they pertain toMassachusetts have satisfied the most de-manding standards of the adversarial pro-cess. EPA’s steadfast refusal to regulategreenhouse gas emissions presents a riskof harm to Massachusetts that is both‘‘actual’’ and ‘‘imminent.’’ Lujan, 504 U.S.,at 560, 112 S.Ct. 2130 (internal quotationmarks omitted). There is, moreover, a‘‘substantial likelihood that the judicial re-lief requested’’ will prompt EPA to takesteps to reduce that risk. Duke Power Co.v. Carolina Environmental Study Group,Inc., 438 U.S. 59, 79, 98 S.Ct. 2620, 57L.Ed.2d 595 (1978).

The Injury

The harms associated with climatechange are serious and well recognized.Indeed, the NRC Report itself—whichEPA regards as an ‘‘objective and inde-pendent assessment of the relevant sci-ence,’’ 68 Fed.Reg. 52930—identifies anumber of environmental changes thathave already inflicted significant harms,including ‘‘the global retreat of mountainglaciers, reduction in snow-cover extent,the earlier spring melting of ice on riversand lakes, [and] the accelerated rate ofrise of sea levels during the 20th centuryrelative to the past few thousand yearsTTT.’’ NRC Report 16.

Petitioners allege that this only hints atthe environmental damage yet to come.According to the climate scientist Michael

17. THE CHIEF JUSTICE accuses the Court ofmisreading Georgia v. Tennessee Copper Co.,206 U.S. 230, 27 S.Ct. 618, 51 L.Ed. 1038(1907), see post, at 1464 – 1465 (dissentingopinion), and ‘‘devis[ing] a new doctrine ofstate standing,’’ post, at 1454 – 1455. But noless an authority than Hart & Wechsler’s TheFederal Courts and the Federal System un-derstands Tennessee Copper as a standing de-cision. R. Fallon, D. Meltzer, & D. Shapiro,Hart & Wechsler’s The Federal Courts andthe Federal System 290 (5th ed.2003). In-deed, it devotes an entire section to chroni-cling the long development of cases permit-ting States ‘‘to litigate as parens patriae toprotect quasi-sovereign interests—i.e., publicor governmental interests that concern thestate as a whole.’’ Id., at 289; see, e.g.,Missouri v. Illinois, 180 U.S. 208, 240–241, 21S.Ct. 331, 45 L.Ed. 497 (1901) (finding feder-al jurisdiction appropriate not only ‘‘in casesinvolving boundaries and jurisdiction overlands and their inhabitants, and in cases di-rectly affecting the property rights and inter-ests of a State,’’ but also when the ‘‘substan-tial impairment of the health and prosperityof the towns and cities of the state’’ are atstake).

Drawing on Massachusetts v. Mellon, 262U.S. 447, 43 S.Ct. 597, 67 L.Ed. 1078 (1923),and Alfred L. Snapp & Son, Inc. v. Puerto Ricoex rel. Barez, 458 U.S. 592, 102 S.Ct. 3260, 73L.Ed.2d 995 (1982) (citing Missouri v. Illi-

nois, 180 U.S. 208, 21 S.Ct. 331, 45 L.Ed. 497(1901)), THE CHIEF JUSTICE claims that we‘‘overloo[k] the fact that our cases cast signifi-cant doubt on a State’s standing to assert aquasi-sovereign interest TTT against the Feder-al Government.’’ Post, at 1466. Not so. Mel-lon itself disavowed any such broad readingwhen it noted that the Court had been ‘‘calledupon to adjudicate, not rights of person orproperty, not rights of dominion over physicaldomain, [and] not quasi-sovereign rights actu-ally invaded or threatened.’’ 262 U.S., at 484–485, 43 S.Ct. 597 (emphasis added). In anyevent, we held in Georgia v. Pennsylvania R.Co., 324 U.S. 439, 447, 65 S.Ct. 716, 89 L.Ed.1051 (1945), that there is a critical differencebetween allowing a State ‘‘to protect her citi-zens from the operation of federal statutes’’(which is what Mellon prohibits) and allowinga State to assert its rights under federal law(which it has standing to do). Massachusettsdoes not here dispute that the Clean Air Actapplies to its citizens; it rather seeks to assertits rights under the Act. See also Nebraska v.Wyoming, 515 U.S. 1, 20, 115 S.Ct. 1933, 132L.Ed.2d 1 (1995) (holding that Wyoming hadstanding to bring a cross-claim against theUnited States to vindicate its ‘‘ ‘quasi-sover-eign’ interests which are ‘independent of andbehind the titles of its citizens, in all the earthand air within its domain’ ’’ (quoting Tennes-see Copper, 206 U.S., at 237, 27 S.Ct. 618)).


MacCracken, ‘‘qualified scientific expertsinvolved in climate change research’’ havereached a ‘‘strong consensus’’ that globalwarming threatens (among other things) aprecipitate rise in sea levels by the end ofthe century, MacCracken Decl. ¶ 5, Stdg.App. 207, ‘‘severe and irreversible changesto natural ecosystems,’’ id., ¶ 5(d), at 209, a‘‘significant reduction in water storage inwinter snowpack in mountainous regionswith direct and important economic conse-quences,’’ ibid., and an increase in thespread of disease, id., ¶ 28, at 218–219.He also observes that rising ocean tem-perSatures522 may contribute to the ferocityof hurricanes. Id., ¶¶ 23–25, at 216–217.18

That these climate-change risks are‘‘widely shared’’ does not minimize Massa-chusetts’ interest in the outcome of thislitigation. See Federal Election Comm’nv. Akins, 524 U.S. 11, 24, 118 S.Ct. 1777,141 L.Ed.2d 10 (1998) (‘‘[W]here a harm isconcrete, though widely shared, the Courthas found ‘injury in fact’ ’’). According topetitioners’ unchallenged affidavits, globalsea levels rose somewhere between 10 and

20 centimeters over the 20th century as aresult of global warming. MacCrackenDecl. ¶ 5(c), Stdg.App. 208. These risingseas have already begun to swallow Mas-sachusetts’ coastal land. Id., at 196 (dec-laration of Paul H. Kirshen ¶ 5), 216(MacCracken Decl. ¶ 23). Because theCommonwealth ‘‘owns a substantial por-tion of the state’s coastal property,’’ id., at171 (declaration of Karst R. Hoogeboom¶ 4),19 it has alleged a particularized injuryin its capacity as a landowner. The se-verity of that injury will S 523only increaseover the course of the next century: Ifsea levels continue to rise as predicted,one Massachusetts official believes that asignificant fraction of coastal property willbe ‘‘either permanently lost through inun-dation or temporarily lost through period-ic storm surge and flooding events.’’ Id.,¶ 6, at 172.20 Remediation costs alone, pe-titioners allege, could run well into thehundreds of millions of dollars. Id., ¶ 7,at 172; see also Kirshen Decl. ¶ 12, at198.21

18. In this regard, MacCracken’s 2004 affida-vit—drafted more than a year in advance ofHurricane Katrina—was eerily prescient.Immediately after discussing the ‘‘particularconcern’’ that climate change might cause an‘‘increase in the wind speed and peak rate ofprecipitation of major tropical cyclones (i.e.,hurricanes and typhoons),’’ MacCracken not-ed that ‘‘[s]oil compaction, sea level rise andrecurrent storms are destroying approximate-ly 20–30 square miles of Louisiana wetlandseach year. These wetlands serve as a ‘shockabsorber’ for storm surges that could inun-date New Orleans, significantly enhancing therisk to a major urban population.’’ ¶¶ 24–25,Stdg.App. 217.

19. ‘‘For example, the [Massachusetts Depart-ment of Conservation and Recreation] owns,operates and maintains approximately 53coastal state parks, beaches, reservations, andwildlife sanctuaries. [It] also owns, operatesand maintains sporting and recreational facil-ities in coastal areas, including numerouspools, skating rinks, playgrounds, playing

fields, former coastal fortifications, publicstages, museums, bike trails, tennis courts,boathouses and boat ramps and landings. As-sociated with these coastal properties and fa-cilities is a significant amount of infrastruc-ture, which the Commonwealth also owns,operates and maintains, including roads,parkways, stormwater pump stations, pier[s],sea wal[l] revetments and dams.’’ Hooge-boom Decl. ¶ 4, at 171.

20. See also id., at 179 (declaration of Chris-tian Jacqz) (discussing possible loss of rough-ly 14 acres of land per miles of coastline by2100); Kirshen Decl. ¶ 10, at 198 (allegingthat ‘‘[w]hen such a rise in sea level occurs, a10–year flood will have the magnitude of thepresent 100–year flood and a 100–year floodwill have the magnitude of the present 500–year flood’’).

21. In dissent, THE CHIEF JUSTICE dismiss-es petitioners’ submissions as ‘‘conclusory,’’presumably because they do not quantify Mas-sachusetts’ land loss with the exactitude he


549 U.S. 525

Causation

EPA does not dispute the existence of acausal connection between manmadegreenhouse gas emissions and globalwarming. At a minimum, therefore,EPA’s refusal to regulate such emissions‘‘contributes’’ to Massachusetts’ injuries.

EPA nevertheless maintains that its de-cision not to regulate greenhouse gas emis-sions from new motor vehicles contributesso insignificantly to petitioners’ injuriesthat the Agency cannot be haled into fed-eral court to answer for them. For thesame reason, EPA does not believe thatany realistic possibility exists that the re-lief petitioners seek would mitigate globalclimate change and remedy their injuries.That is especially so because predictedincreases in greenhouse S 524gas emissionsfrom developing nations, particularly Chi-na and India, are likely to offset any mar-ginal domestic decrease.

But EPA overstates its case. Its argu-ment rests on the erroneous assumptionthat a small incremental step, because it isincremental, can never be attacked in afederal judicial forum. Yet accepting thatpremise would doom most challenges toregulatory action. Agencies, like legisla-tures, do not generally resolve massiveproblems in one fell regulatory swoop.See Williamson v. Lee Optical of Okla.,Inc., 348 U.S. 483, 489, 75 S.Ct. 461, 99L.Ed. 563 (1955) (‘‘[A] reform may takeone step at a time, addressing itself to the

phase of the problem which seems mostacute to the legislative mind’’). They in-stead whittle away at them over time, re-fining their preferred approach as circum-stances change and as they develop a morenuanced understanding of how best to pro-ceed. Cf. SEC v. Chenery Corp., 332 U.S.194, 202, 67 S.Ct. 1575, 91 L.Ed. 1995(1947) (‘‘Some principles must await theirown development, while others must beadjusted to meet particular, unforeseeablesituations’’). That a first step might betentative does not by itself support thenotion that federal courts lack jurisdictionto determine whether that step conformsto law.

And reducing domestic automobile emis-sions is hardly a tentative step. Evenleaving aside the other greenhouse gases,the United States transportation sectoremits an enormous quantity of carbon di-oxide into the atmosphere—according tothe MacCracken affidavit, more than 1.7billion metric tons in 1999 alone. ¶ 30,Stdg.App. 219. That accounts for morethan 6% of worldwide carbon dioxide emis-sions. Id., at 232 (Oppenheimer Decl. ¶ 3);see also MacCracken Decl. ¶ 31, at 220.To put this in perspective: Consideringjust emissions from the transportation sec-tor, which represent less than one-third ofthis country’s total carbon dioxide emis-sions, the United States would still rank asthe third-largest emitter of carbon dioxidein the world, S 525outpaced only by the Eu-ropean Union and China.22 Judged by any

would prefer. Post, at 1467 – 1468. He there-fore asserts that the Commonwealth’s injuryis ‘‘conjectur[al].’’ See ibid. Yet the likeli-hood that Massachusetts’ coastline will recedehas nothing to do with whether petitionershave determined the precise metes andbounds of their soon-to-be-flooded land. Peti-tioners maintain that the seas are rising andwill continue to rise, and have alleged thatsuch a rise will lead to the loss of Massachu-setts’ sovereign territory. No one, save per-

haps the dissenters, disputes those allega-tions. Our cases require nothing more.

22. See UNFCCC, National Greenhouse GasInventory Data for the Period 1990–2004 andStatus of Reporting 14 (2006) (reflectingemissions from Annex I countries); UNFCCC,Sixth Compilation and Synthesis of Initial Na-tional Communications from Parties not In-cluded in Annex I to the Convention 7–8(2005) (reflecting emissions from non-Annex Icountries); see also Dept. of Energy, Energy


standard, U.S. motor-vehicle emissionsmake a meaningful contribution to green-house gas concentrations and hence, ac-cording to petitioners, to global warming.

The Remedy

While it may be true that regulatingmotor-vehicle emissions will not by itselfreverse global warming, it by no meansfollows that we lack jurisdiction to decidewhether EPA has a duty to take steps toslow or reduce it. See also Larson v.Valente, 456 U.S. 228, 244, n. 15, 102 S.Ct.1673, 72 L.Ed.2d 33 (1982) (‘‘[A] plaintiffsatisfies the redressability requirementwhen he shows that a favorable decisionwill relieve a discrete injury to himself.He need not show that a favorable decisionwill relieve his every injury’’). Because ofthe enormity of the potential consequencesassociated with manmade climate change,the fact that the effectiveness of a remedymight be delayed during the (relativelyshort) time it takes for a new motor-vehi-cle fleet to replace an older one is essen-tially irrelevant.23 Nor is it dispositivethat developing countries such as Chinaand India are poised to increase green-house gas emissions S 526substantially overthe next century: A reduction in domesticemissions would slow the pace of global

emissions increases, no matter what hap-pens elsewhere.

We moreover attach considerable signifi-cance to EPA’s ‘‘agree[ment] with thePresident that ‘we must address the issueof global climate change,’ ’’ 68 Fed.Reg.52929 (quoting remarks announcing ClearSkies and Global Climate Initiatives, 2002Public Papers of George W. Bush, Vol. 1,Feb. 14, p. 227 (2004)), and to EPA’s ar-dent support for various voluntary emis-sion-reduction programs, 68 Fed.Reg.52932. As Judge Tatel observed in dissentbelow, ‘‘EPA would presumably not botherwith such efforts if it thought emissionsreductions would have no discernable im-pact on future global warming.’’ 415 F.3d,at 66.

In sum—at least according to petition-ers’ uncontested affidavits—the rise in sealevels associated with global warming hasalready harmed and will continue to harmMassachusetts. The risk of catastrophicharm, though remote, is nevertheless real.That risk would be reduced to some extentif petitioners received the relief they seek.We therefore hold that petitioners havestanding to challenge EPA’s denial of theirrulemaking petition.24

Information Admin., International Energy An-nual 2004, H.1co2 World Carbon DioxideEmissions from the Consumption and Flaringof Fossil Fuels, 1980–2004 (Table), http://www.eia.doe.gov/pub/international/iealf/tableh1co2.xls.

23. See also Mountain States Legal Foundationv. Glickman, 92 F.3d 1228, 1234 (C.A.D.C.1996) (‘‘The more drastic the injury that gov-ernment action makes more likely, the lesserthe increment in probability to establishstanding’’); Village of Elk Grove Village v.Evans, 997 F.2d 328, 329 (C.A.7 1993)(‘‘[E]ven a small probability of injury is suffi-cient to create a case or controversy—to takea suit out of the category of the hypothetical—provided of course that the relief soughtwould, if granted, reduce the probability’’).

24. In his dissent, THE CHIEF JUSTICE ex-presses disagreement with the Court’s holdingin United States v. Students Challenging Regu-latory Agency Procedures (SCRAP), 412 U.S.669, 687–688, 93 S.Ct. 2405, 37 L.Ed.2d 254(1973). He does not, however, disavow thisportion of Justice Stewart’s opinion for theCourt:

‘‘Unlike the specific and geographically limit-ed federal action of which the petitioner com-plained in Sierra Club [v. Morton, 405 U.S.727, 92 S.Ct. 1361, 31 L.Ed.2d 636 (1972) ],the challenged agency action in this case isapplicable to substantially all of the Nation’srailroads, and thus allegedly has an adverseenvironmental impact on all the natural re-sources of the country. Rather than a limitedgroup of persons who used a picturesque val-ley in California, all persons who utilize the


549 U.S. 528

S 527V

[5, 6] The scope of our review of themerits of the statutory issues is narrow.As we have repeated time and again, anagency has broad discretion to choose howbest to marshal its limited resources andpersonnel to carry out its delegated re-sponsibilities. See Chevron U.S.A. Inc. v.Natural Resources Defense Council, Inc.,467 U.S. 837, 842–845, 104 S.Ct. 2778, 81L.Ed.2d 694 (1984). That discretion is atits height when the agency decides not tobring an enforcement action. Therefore,in Heckler v. Chaney, 470 U.S. 821, 105S.Ct. 1649, 84 L.Ed.2d 714 (1985), we heldthat an agency’s refusal to initiate enforce-ment proceedings is not ordinarily subjectto judicial review. Some debate remains,however, as to the rigor with which wereview an agency’s denial of a petition forrulemaking.

[7] There are key differences betweena denial of a petition for rulemaking andan agency’s decision not to initiate an en-forcement action. See American HorseProtection Assn., Inc. v. Lyng, 812 F.2d 1,3–4 (C.A.D.C.1987). In contrast to nonen-forcement decisions, agency refusals to ini-tiate rulemaking ‘‘are less frequent, moreapt to involve legal as opposed to factualanalysis, and subject to special formalities,including a public explanation.’’ Id., at 4;see also 5 U.S.C. § 555(e). They more-over arise out of denials of petitions forrulemaking which (at least in the circum-stances here) the affected party had an

undoubted procedural right to file in thefirst instance. Refusals to promulgaterules are thus susceptible to judicial re-view, though such review is ‘‘exStremely528

limited’’ and ‘‘highly deferential.’’ Nation-al Customs Brokers & Forwarders Assn.of America, Inc. v. United States, 883 F.2d93, 96 (C.A.D.C.1989).

EPA concluded in its denial of the peti-tion for rulemaking that it lacked authorityunder 42 U.S.C. § 7521(a)(1) to regulatenew vehicle emissions because carbon diox-ide is not an ‘‘air pollutant’’ as that term isdefined in § 7602. In the alternative, itconcluded that even if it possessed authori-ty, it would decline to do so because regu-lation would conflict with other administra-tion priorities. As discussed earlier, theClean Air Act expressly permits review ofsuch an action. § 7607(b)(1). We therefore‘‘may reverse any such action found to beTTT arbitrary, capricious, an abuse of dis-cretion, or otherwise not in accordancewith law.’’ § 7607(d)(9).

VI

[8] On the merits, the first question iswhether § 202(a)(1) of the Clean Air Actauthorizes EPA to regulate greenhousegas emissions from new motor vehicles inthe event that it forms a ‘‘judgment’’ thatsuch emissions contribute to climatechange. We have little trouble concludingthat it does. In relevant part, § 202(a)(1)provides that EPA ‘‘shall by regulation

scenic resources of the country, and indeedall who breathe its air, could claim harmsimilar to that alleged by the environmentalgroups here. But we have already made itclear that standing is not to be denied simplybecause many people suffer the same injury.Indeed some of the cases on which we reliedin Sierra Club demonstrated the patent factthat persons across the Nation could be ad-versely affected by major governmental ac-tions. To deny standing to persons who are in

fact injured simply because many others arealso injured, would mean that the most injuri-ous and widespread Government actions couldbe questioned by nobody. We cannot acceptthat conclusion.’’ Ibid. (citations omitted andemphasis added).It is moreover quite wrong to analogize thelegal claim advanced by Massachusetts andthe other public and private entities who chal-lenge EPA’s parsimonious construction of theClean Air Act to a mere ‘‘lawyer’s game.’’See post, at 1471.


prescribe TTT standards applicable to theemission of any air pollutant from anyclass or classes of new motor vehicles ornew motor vehicle engines, which in [theAdministrator’s] judgment cause, or con-tribute to, air pollution which may reason-ably be anticipated to endanger publichealth or welfare.’’ 42 U.S.C. § 7521(a)(1).Because EPA believes that Congress didnot intend it to regulate substances thatcontribute to climate change, the agencymaintains that carbon dioxide is not an ‘‘airpollutant’’ within the meaning of the provi-sion.

The statutory text forecloses EPA’sreading. The Clean Air Act’s sweepingdefinition of ‘‘air pollutant’’ includes ‘‘anyair pollution agent or combination of suchagents, including any physical, chemicalTTT substance or matter which isemitSted529 into or otherwise enters the am-bient air TTT .’’ § 7602(g) (emphasis add-ed). On its face, the definition embracesall airborne compounds of whatever stripe,and underscores that intent through therepeated use of the word ‘‘any.’’ 25 Carbon

dioxide, methane, nitrous oxide, and hydro-fluorocarbons are without a doubt ‘‘physi-cal [and] chemical TTT substance[s] which[are] emitted into TTT the ambient air.’’The statute is unambiguous.26

Rather than relying on statutory text,EPA invokes postenactment congressionalactions and deliberations it views as tanta-mount to a congressional command to re-frain from regulating greenhouse gasemissions. Even if such postenactmentlegislative history could shed light on themeaning of an otherwise-unambiguousstatute, EPA never identifies any actionremotely suggesting that Congress meantto curtail its power to treat greenhousegases as air pollutants. That subsequentCongresses have eschewed enactingbindSing530 emissions limitations to combatglobal warming tells us nothing about whatCongress meant when it amended§ 202(a)(1) in 1970 and 1977.27 And unlikeEPA, we have no difficulty reconcilingCongress’ various efforts to promote inter-agency collaboration and research to bet-

25. See Department of Housing and Urban De-velopment v. Rucker, 535 U.S. 125, 131, 122S.Ct. 1230, 152 L.Ed.2d 258 (2002) (observ-ing that ‘‘ ‘any’ TTT has an expansive mean-ing, that is, one or some indiscriminately ofwhatever kind’’ (some internal quotationmarks omitted)).

26. In dissent, Justice SCALIA maintains thatbecause greenhouse gases permeate theworld’s atmosphere rather than a limited areanear the earth’s surface, EPA’s exclusion ofgreenhouse gases from the category of airpollution ‘‘agent[s]’’ is entitled to deferenceunder Chevron U.S.A. Inc. v. Natural Re-sources Defense Council, Inc., 467 U.S. 837,104 S.Ct. 2778, 81 L.Ed.2d 694 (1984). Seepost, at 1469 – 1470. EPA’s distinction, how-ever, finds no support in the text of the stat-ute, which uses the phrase ‘‘the ambient air’’without distinguishing between atmosphericlayers. Moreover, it is a plainly unreasonablereading of a sweeping statutory provision de-signed to capture ‘‘any physical, chemical TTT

substance or matter which is emitted into orotherwise enters the ambient air.’’ 42 U.S.C.§ 7602(g). Justice SCALIA does not (andcannot) explain why Congress would define‘‘air pollutant’’ so carefully and so broadly,yet confer on EPA the authority to narrowthat definition whenever expedient by assert-ing that a particular substance is not an‘‘agent.’’ At any rate, no party to this disputecontests that greenhouse gases both ‘‘ente[r]the ambient air’’ and tend to warm the atmo-sphere. They are therefore unquestionably‘‘agent[s]’’ of air pollution.

27. See United States v. Price, 361 U.S. 304,313, 80 S.Ct. 326, 4 L.Ed.2d 334 (1960) (hold-ing that ‘‘the views of a subsequent Congressform a hazardous basis for inferring the in-tent of an earlier one’’); see also Cobell v.Norton, 428 F.3d 1070, 1075 (C.A.D.C.2005)(‘‘[P]ost-enactment legislative history is notonly oxymoronic but inherently entitled tolittle weight’’).


549 U.S. 531

ter understand climate change 28 with theAgency’s pre-existing mandate to regulate‘‘any air pollutant’’ that may endanger thepublic welfare. See 42 U.S.C.§ 7601(a)(1). Collaboration and researchdo not conflict with any thoughtful regula-tory effort; they complement it.29

EPA’s reliance on Brown & WilliamsonTobacco Corp., 529 U.S. 120, 120 S.Ct.1291, 146 L.Ed.2d 121, is similarly mis-placed. In holding that tobacco productsare not ‘‘drugs’’ or ‘‘devices’’ subject toFood and Drug Administration (FDA) reg-ulation pursuant to the Food, Drug andCosmetic Act (FDCA), see 529 U.S., at133, 120 S.Ct. 1291, we S 531found critical atleast two considerations that have no coun-terpart in this case.

First, we thought it unlikely that Con-gress meant to ban tobacco products,which the FDCA would have required hadsuch products been classified as ‘‘drugs’’ or‘‘devices.’’ Id., at 135–137, 120 S.Ct. 1291.Here, in contrast, EPA jurisdiction wouldlead to no such extreme measures. EPAwould only regulate emissions, and eventhen, it would have to delay any action ‘‘topermit the development and application ofthe requisite technology, giving appropri-ate consideration to the cost of compli-ance,’’ § 7521(a)(2). However much a banon tobacco products clashed with the ‘‘com-

mon sense’’ intuition that Congress nevermeant to remove those products from cir-culation, Brown & Williamson, 529 U.S.,at 133, 120 S.Ct. 1291, there is nothingcounterintuitive to the notion that EPAcan curtail the emission of substances thatare putting the global climate out of kilter.

Second, in Brown & Williamson wepointed to an unbroken series of congres-sional enactments that made sense only ifadopted ‘‘against the backdrop of theFDA’s consistent and repeated statementsthat it lacked authority under the FDCAto regulate tobacco.’’ Id., at 144, 120 S.Ct.1291. We can point to no such enactmentshere: EPA has not identified any congres-sional action that conflicts in any way withthe regulation of greenhouse gases fromnew motor vehicles. Even if it had, Con-gress could not have acted against a regu-latory ‘‘backdrop’’ of disclaimers of regula-tory authority. Prior to the order thatprovoked this litigation, EPA had neverdisavowed the authority to regulate green-house gases, and in 1998 it in fact affirmedthat it had such authority. See App. 54(Cannon memorandum). There is no rea-son, much less a compelling reason, toaccept EPA’s invitation to read ambiguityinto a clear statute.

[9] EPA finally argues that it cannotregulate carbon dioxide emissions from

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 NationalClimate Program and for additional climate-change research); Global Climate ProtectionAct of 1987, § 1103, 101 Stat. 1408–1409,note following 15 U.S.C. § 2901 (directingEPA and the Secretary of State to ‘‘jointly’’develop a ‘‘coordinated national policy onglobal climate change’’ and report to Con-gress); Global Change Research Act of 1990,Tit. I, 104 Stat. 3097, 15 U.S.C. §§ 2921–2938(establishing for the ‘‘development and coor-dination of a comprehensive and integratedUnited States research program’’ to aid in‘‘understand[ing] TTT human-induced and nat-

ural processes of climate change’’); GlobalClimate Change Prevention Act of 1990, 104Stat. 4058, 7 U.S.C. § 6701 et seq. (directingthe Dept. of Agriculture to study the effects ofclimate change on forestry and agriculture);Energy Policy Act of 1992, §§ 1601–1609, 106Stat. 2999, 42 U.S.C. §§ 13381–13388 (re-quiring the Secretary of Energy to report oninformation pertaining to climate change).

29. We are moreover puzzled by EPA’s round-about argument that because later Congresseschose to address stratospheric ozone pollu-tion in a specific legislative provision, it some-how follows that greenhouse gases cannot beair pollutants within the meaning of the CleanAir Act.


motor vehicles because doing so would re-quire it to tighten mileage standards, a job(according to S 532EPA) that Congress hasassigned to DOT. See 68 Fed.Reg. 52929.But that DOT sets mileage standards in noway licenses EPA to shirk its environmen-tal responsibilities. EPA has beencharged with protecting the public’s‘‘health’’ and ‘‘welfare,’’ 42 U.S.C.§ 7521(a)(1), a statutory obligation whollyindependent of DOT’s mandate to promoteenergy efficiency. See Energy Policy andConservation Act, § 2(5), 89 Stat. 874, 42U.S.C. § 6201(5). The two obligationsmay overlap, but there is no reason tothink the two agencies cannot both admin-ister their obligations and yet avoid incon-sistency.

While the Congresses that drafted§ 202(a)(1) might not have appreciated thepossibility that burning fossil fuels couldlead to global warming, they did under-stand that without regulatory flexibility,changing circumstances and scientific de-velopments would soon render the CleanAir Act obsolete. The broad language of§ 202(a)(1) reflects an intentional effort toconfer the flexibility necessary to forestallsuch obsolescence. See PennsylvaniaDept. of Corrections v. Yeskey, 524 U.S.206, 212, 118 S.Ct. 1952, 141 L.Ed.2d 215(1998) (‘‘[T]he fact that a statute can beapplied in situations not expressly antici-pated by Congress does not demonstrateambiguity. It demonstrates breadth’’ (in-ternal quotation marks omitted)). Be-cause greenhouse gases fit well within theClean Air Act’s capacious definition of ‘‘airpollutant,’’ we hold that EPA has the stat-utory authority to regulate the emission ofsuch gases from new motor vehicles.

VII

The alternative basis for EPA’s deci-sion—that even if it does have statutoryauthority to regulate greenhouse gases, it

would be unwise to do so at this time—rests on reasoning divorced from the stat-utory text. While the statute does condi-tion the exercise of EPA’s authority on itsformation of a ‘‘judgment,’’ 42 U.S.C.§ 7521(a)(1), that judgment must relate towhether an air pollutant ‘‘cause[s], or con-tribute[s] to, air pollution which may rea-sonably be anticipated to enSdanger533 pub-lic health or welfare,’’ ibid. Put anotherway, the use of the word ‘‘judgment’’ is nota roving license to ignore the statutorytext. It is but a direction to exercisediscretion within defined statutory limits.

[10] If EPA makes a finding of endan-germent, the Clean Air Act requires theAgency to regulate emissions of the delete-rious pollutant from new motor vehicles.Ibid. (stating that ‘‘[EPA] shall by regula-tion prescribe TTT standards applicable tothe emission of any air pollutant from anyclass or classes of new motor vehicles’’).EPA no doubt has significant latitude as tothe manner, timing, content, and coordina-tion of its regulations with those of otheragencies. But once EPA has responded toa petition for rulemaking, its reasons foraction or inaction must conform to theauthorizing statute. Under the clearterms of the Clean Air Act, EPA can avoidtaking further action only if it determinesthat greenhouse gases do not contribute toclimate change or if it provides some rea-sonable explanation as to why it cannot orwill not exercise its discretion to determinewhether they do. Ibid. To the extent thatthis constrains agency discretion to pursueother priorities of the Administrator or thePresident, this is the congressional design.

[11] EPA has refused to comply withthis clear statutory command. Instead, ithas offered a laundry list of reasons not toregulate. For example, EPA said that anumber of voluntary Executive Branchprograms already provide an effective re-sponse to the threat of global warming, 68


549 U.S. 535

Fed.Reg. 52932, that regulating green-house gases might impair the President’sability to negotiate with ‘‘key developingnations’’ to reduce emissions, id., at 52931,and that curtailing motor-vehicle emissionswould reflect ‘‘an inefficient, piecemeal ap-proach to address the climate change is-sue,’’ ibid.

Although we have neither the expertisenor the authority to evaluate these policyjudgments, it is evident they have nothingto do with whether greenhouse gas emis-sions contribute to climate change. Stillless do they amount to a S 534reasoned justi-fication for declining to form a scientificjudgment. In particular, while the Presi-dent has broad authority in foreign affairs,that authority does not extend to the re-fusal to execute domestic laws. In theGlobal Climate Protection Act of 1987,Congress authorized the State Depart-ment—not EPA—to formulate UnitedStates foreign policy with reference to en-vironmental matters relating to climate.See § 1103(c), 101 Stat. 1409. EPA hasmade no showing that it issued the rulingin question here after consultation with theState Department. Congress did directEPA to consult with other agencies in theformulation of its policies and rules, butthe State Department is absent from thatlist. § 1103(b).

[12] Nor can EPA avoid its statutoryobligation by noting the uncertainty sur-rounding various features of climatechange and concluding that it would there-fore be better not to regulate at this time.See 68 Fed.Reg. 52930–52931. If the sci-entific uncertainty is so profound that itprecludes EPA from making a reasonedjudgment as to whether greenhouse gasescontribute to global warming, EPA mustsay so. That EPA would prefer not toregulate greenhouse gases because ofsome residual uncertainty—which, con-trary to Justice SCALIA’s apparent belief,

post, at 1466 – 1468, is in fact all that itsaid, see 68 Fed.Reg. 52929–52930 (‘‘We donot believe TTT that it would be eithereffective or appropriate for EPA to estab-lish [greenhouse gas] standards for motorvehicles at this time’’ (emphasis added))—is irrelevant. The statutory question iswhether sufficient information exists tomake an endangerment finding.

In short, EPA has offered no reasonedexplanation for its refusal to decide wheth-er greenhouse gases cause or contribute toclimate change. Its action was therefore‘‘arbitrary, capricious, TTT or otherwise notin accordance with law.’’ 42 U.S.C.§ 7607(d)(9)(A). We need not and do notreach the question whether on remandEPA must make an endangerment finding,or whether policy concerns can informS 535EPA’s actions in the event that it makessuch a finding. Cf. Chevron U.S.A. Inc. v.Natural Resources Defense Council, Inc.,467 U.S. 843–844, 104 S.Ct. 2778, 81L.Ed.2d 694, at 1. We hold only that EPAmust ground its reasons for action or inac-tion in the statute.

VIII

The judgment of the Court of Appeals isreversed, and the case is remanded forfurther proceedings consistent with thisopinion.

It is so ordered.

Chief Justice ROBERTS, with whomJustice SCALIA, Justice THOMAS, andJustice ALITO join, dissenting.

Global warming may be a ‘‘crisis,’’ even‘‘the most pressing environmental problemof our time.’’ Pet. for Cert. 26, 22. In-deed, it may ultimately affect nearly every-one on the planet in some potentially ad-verse way, and it may be that governmentshave done too little to address it. It is nota problem, however, that has escaped theattention of policymakers in the Executive


and Legislative Branches of our Govern-ment, who continue to consider regulatory,legislative, and treaty-based means of ad-dressing global climate change.

Apparently dissatisfied with the pace ofprogress on this issue in the electedbranches, petitioners have come to thecourts claiming broad-ranging injury, andattempting to tie that injury to the Gov-ernment’s alleged failure to comply with arather narrow statutory provision. Iwould reject these challenges as nonjustici-able. Such a conclusion involves no judg-ment on whether global warming exists,what causes it, or the extent of the prob-lem. Nor does it render petitioners with-out recourse. This Court’s standing juris-prudence simply recognizes that redress ofgrievances of the sort at issue here ‘‘is thefunction of Congress and the Chief Execu-tive,’’ not the federal courts. Lujan v.Defenders of Wildlife, 504 U.S. 555, 576,112 S.Ct. 2130, 119 L.Ed.2d 351 (1992). Iwould vacate the judgSment536 below andremand for dismissal of the petitions forreview.

I

Article III, § 2, of the Constitution lim-its the federal judicial power to the adjudi-cation of ‘‘Cases’’ and ‘‘Controversies.’’ ‘‘Ifa dispute is not a proper case or controver-sy, the courts have no business deciding it,or expounding the law in the course ofdoing so.’’ DaimlerChrysler Corp. v.Cuno, 547 U.S. 332, 341, 126 S.Ct. 1854,1860–1861, 164 L.Ed.2d 589 (2006).‘‘Standing to sue is part of the commonunderstanding of what it takes to make ajusticiable case,’’ Steel Co. v. Citizens forBetter Environment, 523 U.S. 83, 102, 118S.Ct. 1003, 140 L.Ed.2d 210 (1998), and hasbeen described as ‘‘an essential and un-changing part of the case-or-controversyrequirement of Article III,’’ Defenders ofWildlife, supra, at 560, 112 S.Ct. 2130.

Our modern framework for addressingstanding is familiar: ‘‘A plaintiff must al-lege personal injury fairly traceable to thedefendant’s allegedly unlawful conduct andlikely to be redressed by the requestedrelief.’’ DaimlerChrysler, supra, at 342,126 S.Ct., at 1861 (quoting Allen v. Wright,468 U.S. 737, 751, 104 S.Ct. 3315, 82L.Ed.2d 556 (1984); (internal quotationmarks omitted)). Applying that standardhere, petitioners bear the burden of alleg-ing an injury that is fairly traceable to theEnvironmental Protection Agency’s failureto promulgate new motor vehicle green-house gas emission standards, and that islikely to be redressed by the prospectiveissuance of such standards.

Before determining whether petitionerscan meet this familiar test, however, theCourt changes the rules. It asserts that‘‘States are not normal litigants for thepurposes of invoking federal jurisdiction,’’and that given ‘‘Massachusetts’ stake inprotecting its quasi-sovereign interests,the Commonwealth is entitled to specialsolicitude in our standing analysis.’’ Ante,at 1454, 1455 (emphasis added).

Relaxing Article III standing require-ments because asserted injuries arepressed by a State, however, has no basisin our jurisprudence, and support for anysuch ‘‘special solicitude’’ is conspicuouslyabsent from the Court’s opinion. The gen-eral judicial review provision cited by theCourt, 42 S 537U.S.C. § 7607(b)(1), affordsStates no special rights or status. TheCourt states that ‘‘Congress has orderedEPA to protect Massachusetts (among oth-ers)’’ through the statutory provision atissue, § 7521(a)(1), and that ‘‘Congress hasTTT recognized a concomitant proceduralright to challenge the rejection of its rule-making petition as arbitrary and capri-cious.’’ Ante, at 1454. The reader mightthink from this unfortunate phrasing thatCongress said something about the rights


549 U.S. 538

of States in this particular provision of thestatute. Congress knows how to do thatwhen it wants to, see, e.g., § 7426(b) (af-fording States the right to petition EPA todirectly regulate certain sources of pollu-tion), but it has done nothing of the sorthere. Under the law on which petitionersrely, Congress treated public and privatelitigants exactly the same.

Nor does the case law cited by the Courtprovide any support for the notion thatArticle III somehow implicitly treats pub-lic and private litigants differently. TheCourt has to go back a full century in anattempt to justify its novel standing rule,but even there it comes up short. TheCourt’s analysis hinges on Georgia v. Ten-nessee Copper Co., 206 U.S. 230, 27 S.Ct.618, 51 L.Ed. 1038 (1907)—a case that didindeed draw a distinction between a Stateand private litigants, but solely with re-spect to available remedies. The case hadnothing to do with Article III standing.

In Tennessee Copper, the State of Geor-gia sought to enjoin copper companies inneighboring Tennessee from dischargingpollutants that were inflicting ‘‘a wholesaledestruction of forests, orchards and crops’’in bordering Georgia counties. Id., at 236,27 S.Ct. 618. Although the State ownedvery little of the territory allegedly affect-ed, the Court reasoned that Georgia—inits capacity as a ‘‘quasi-sovereign’’—‘‘hasan interest independent of and behind thetitles of its citizens, in all the earth and airwithin its domain.’’ Id., at 237, 27 S.Ct.618. The Court explained that while ‘‘[t]hevery elements that would be relied upon ina suit between fellow-citizens as a groundfor equitable relief [were] wanting,’’ aState ‘‘is not lightly to be reSquired538 togive up quasi-sovereign rights for pay.’’Ibid. Thus while a complaining private liti-gant would have to make do with a legalremedy—one ‘‘for pay’’—the State was en-

titled to equitable relief. See id., at 237–238, 27 S.Ct. 618.

In contrast to the present case, therewas no question in Tennessee Copperabout Article III injury. See id., at 238–239, 27 S.Ct. 618. There was certainly nosuggestion that the State could showstanding where the private parties couldnot; there was no dispute, after all, thatthe private landowners had ‘‘an action atlaw.’’ Id., at 238, 27 S.Ct. 618. TennesseeCopper has since stood for nothing morethan a State’s right, in an original jurisdic-tion action, to sue in a representative ca-pacity as parens patriae. See, e.g., Mary-land v. Louisiana, 451 U.S. 725, 737, 101S.Ct. 2114, 68 L.Ed.2d 576 (1981). Noth-ing about a State’s ability to sue in thatcapacity dilutes the bedrock requirementof showing injury, causation, and redressa-bility to satisfy Article III.

A claim of parens patriae standing isdistinct from an allegation of direct injury.See Wyoming v. Oklahoma, 502 U.S. 437,448–449, 451, 112 S.Ct. 789, 117 L.Ed.2d 1(1992). Far from being a substitute forArticle III injury, parens patriae actionsraise an additional hurdle for a state liti-gant: the articulation of a ‘‘quasi-sovereigninterest’’ ‘‘apart from the interests of par-ticular private parties.’’ Alfred L. Snapp& Son, Inc. v. Puerto Rico ex rel. Barez,458 U.S. 592, 607, 102 S.Ct. 3260, 73L.Ed.2d 995 (1982) (emphasis added) (citedante, at 1454). Just as an association su-ing on behalf of its members must shownot only that it represents the membersbut that at least one satisfies Article IIIrequirements, so too a State asserting qua-si-sovereign interests as parens patriaemust still show that its citizens satisfyArticle III. Focusing on Massachusetts’sinterests as quasi-sovereign makes the re-quired showing here harder, not easier.The Court, in effect, takes what has alwaysbeen regarded as a necessary condition for


parens patriae standing—a quasi-sover-eign interest—and converts it into a suffi-cient showing for purposes of Article III.

S 539What is more, the Court’s reasoningfalters on its own terms. The Court as-serts that Massachusetts is entitled to‘‘special solicitude’’ due to its ‘‘quasi-sover-eign interests,’’ ante, at 1455, but thenapplies our Article III standing test to theasserted injury of the Commonwealth’sloss of coastal property. See ante, at 1456(concluding that Massachusetts ‘‘has al-leged a particularized injury in its capaci-ty as a landowner ’’ (emphasis added)). Inthe context of parens patriae standing,however, we have characterized state own-ership of land as a ‘‘nonsovereign in-teres[t]’’ because a State ‘‘is likely to havethe same interests as other similarly situ-ated proprietors.’’ Alfred L. Snapp &Son, supra, at 601, 102 S.Ct. 3260.

On top of everything else, the Courtoverlooks the fact that our cases cast sig-nificant doubt on a State’s standing toassert a quasi-sovereign interest—as op-posed to a direct injury—against the Fed-eral Government. As a general rule, wehave held that while a State might assert aquasi-sovereign right as parens patriae‘‘for the protection of its citizens, it is nopart of its duty or power to enforce theirrights in respect of their relations with theFederal Government. In that field it is

the United States, and not the State, whichrepresents them.’’ Massachusetts v. Mel-lon, 262 U.S. 447, 485–486, 43 S.Ct. 597, 67L.Ed. 1078 (1923) (citation omitted); seealso Alfred L. Snapp & Son, supra, at 610,n. 16, 102 S.Ct. 3260.

All of this presumably explains why peti-tioners never cited Tennessee Copper intheir briefs before this Court or the D.C.Circuit. It presumably explains why notone of the legion of amici supporting peti-tioners ever cited the case. And it pre-sumably explains why not one of the threejudges writing below ever cited the caseeither. Given that one purpose of thestanding requirement is ‘‘ ‘to assure thatconcrete adverseness which sharpens thepresentation of issues upon which thecourt so largely depends for illumination,’ ’’ante, at 1452 – 1453 (quoting Baker v.Carr, 369 U.S. 186, 204, 82 S.Ct. 691, 7L.Ed.2d 663 (1962)), it is ironic that theCourt today adopts a new theory S 540ofArticle III standing for States without thebenefit of briefing or argument on thepoint.1

II

It is not at all clear how the Court’s‘‘special solicitude’’ for Massachusettsplays out in the standing analysis, exceptas an implicit concession that petitionerscannot establish standing on traditionalterms. But the status of Massachusetts as

1. The Court seems to think we do not recog-nize that Tennessee Copper is a case aboutparens patriae standing, ante, at 1455, n. 17,but we have no doubt about that. The pointis that nothing in our cases (or Hart & Wech-sler) suggests that the prudential require-ments for parens patriae standing, see Repub-lic of Venezuela v. Philip Morris Inc., 287 F.3d192, 199, n. (CADC 2002) (observing that‘‘parens patriae is merely a species of pruden-tial standing’’ (internal quotation marks omit-ted)), can somehow substitute for, or alter thecontent of, the ‘‘irreducible constitutionalminimum’’ requirements of injury in fact,causation, and redressability under Article

III. Lujan v. Defenders of Wildlife, 504 U.S.555, 560, 112 S.Ct. 2130, 119 L.Ed.2d 351(1992).

Georgia v. Pennsylvania R. Co., 324 U.S.439, 65 S.Ct. 716, 89 L.Ed. 1051 (1945), is notto the contrary. As the caption makes clearenough, the fact that a State may assert rightsunder a federal statute as parens patriae in noway refutes our clear ruling that ‘‘[a] Statedoes not have standing as parens patriae tobring an action against the Federal Govern-ment.’’ Alfred L. Snapp & Son, Inc. v. PuertoRico ex rel. Barez, 458 U.S. 592, 610, n. 16,102 S.Ct. 3260, 73 L.Ed.2d 995 (1982).


549 U.S. 542

a State cannot compensate for petitioners’failure to demonstrate injury in fact, cau-sation, and redressability.

When the Court actually applies thethree-part test, it focuses, as did the dis-sent below, see 415 F.3d 50, 64 (C.A.D.C.2005) (opinion of Tatel, J.), on the Com-monwealth’s asserted loss of coastal landas the injury in fact. If petitioners rely onloss of land as the Article III injury, how-ever, they must ground the rest of thestanding analysis in that specific injury.That alleged injury must be ‘‘concrete andparticularized,’’ Defenders of Wildlife, 504S 541U.S., at 560, 112 S.Ct. 2130, and ‘‘dis-tinct and palpable,’’ Allen, 468 U.S., at 751,104 S.Ct. 3315 (internal quotation marksomitted). Central to this concept of ‘‘par-ticularized’’ injury is the requirement thata plaintiff be affected in a ‘‘personal andindividual way,’’ Defenders of Wildlife, 504U.S., at 560, n. 1, 112 S.Ct. 2130, and seekrelief that ‘‘directly and tangibly benefitshim’’ in a manner distinct from its impacton ‘‘the public at large,’’ id., at 573–574,112 S.Ct. 2130. Without ‘‘particularizedinjury, there can be no confidence of ‘areal need to exercise the power of judicialreview’ or that relief can be framed ‘nobroader than required by the precise factsto which the court’s ruling would be ap-plied.’ ’’ Warth v. Seldin, 422 U.S. 490,508, 95 S.Ct. 2197, 45 L.Ed.2d 343 (1975)(quoting Schlesinger v. Reservists Comm.to Stop the War, 418 U.S. 208, 221–222, 94S.Ct. 2925, 41 L.Ed.2d 706 (1974)).

The very concept of global warmingseems inconsistent with this particulariza-tion requirement. Global warming is aphenomenon ‘‘harmful to humanity atlarge,’’ 415 F.3d, at 60 (Sentelle, J., dis-senting in part and concurring in judg-ment), and the redress petitioners seek isfocused no more on them than on thepublic generally—it is literally to changethe atmosphere around the world.

If petitioners’ particularized injury isloss of coastal land, it is also that injurythat must be ‘‘actual or imminent, not con-jectural or hypothetical,’’ Defenders ofWildlife, supra, at 560, 112 S.Ct. 2130(internal quotation marks omitted), ‘‘realand immediate,’’ Los Angeles v. Lyons, 461U.S. 95, 102, 103 S.Ct. 1660, 75 L.Ed.2d675 (1983) (internal quotation marks omit-ted), and ‘‘certainly impending,’’ Whitmorev. Arkansas, 495 U.S. 149, 158, 110 S.Ct.1717, 109 L.Ed.2d 135 (1990) (internal quo-tation marks omitted).

As to ‘‘actual’’ injury, the Court observesthat ‘‘global sea levels rose somewherebetween 10 and 20 centimeters over the20th century as a result of global warm-ing’’ and that ‘‘[t]hese rising seas havealready begun to swallow Massachusetts’coastal land.’’ Ante, at 1456. But none ofpetitioners’ declarations supports that con-nection. One declaration states that ‘‘arise in sea level due to climate change isoccurring on the coast of Massachusetts, inthe metropolitan Boston area,’’ but there isno elaboration. Petitioners’ Standing Ap-pendix in No. 03–1361, etc. (CADC), p.196 (Stdg.App.). And the declarant goeson to identify a ‘‘significan[t]’’ non-global-warming cause of Boston’s rising sea level:land S 542subsidence. Id., at 197; see alsoid., at 216. Thus, aside from a singleconclusory statement, there is nothing inpetitioners’ 43 standing declarations andaccompanying exhibits to support an infer-ence of actual loss of Massachusetts coast-al land from 20th-century global sea levelincreases. It is pure conjecture.

The Court’s attempts to identify ‘‘immi-nent’’ or ‘‘certainly impending’’ loss ofMassachusetts coastal land fares no better.See ante, at 1456, 1457. One of petition-ers’ declarants predicts global warmingwill cause sea level to rise by 20 to 70centimeters by the year 2100. Stdg.App.216. Another uses a computer modeling


program to map the Commonwealth’scoastal land and its current elevation, andcalculates that the high-end estimate ofsea level rise would result in the loss ofsignificant state-owned coastal land. Id.,at 179. But the computer modeling pro-gram has a conceded average error ofabout 30 centimeters and a maximum ob-served error of 70 centimeters. Id., at177–178. As an initial matter, if it is possi-ble that the model underrepresents theelevation of coastal land to an extent equalto or in excess of the projected sea levelrise, it is difficult to put much stock in thepredicted loss of land. But even placingthat problem to the side, accepting a cen-tury-long time horizon and a series of com-pounded estimates renders requirementsof imminence and immediacy utterly tooth-less. See Defenders of Wildlife, supra, at565, n. 2, 112 S.Ct. 2130 (while the conceptof ‘‘ ‘imminence’ ’’ in standing doctrine is‘‘somewhat elastic,’’ it can be ‘‘stretchedbeyond the breaking point’’). ‘‘Allegationsof possible future injury do not satisfy therequirements of Art. III. A threatenedinjury must be certainly impending toconstitute injury in fact.’’ Whitmore, su-pra, at 158, 110 S.Ct. 1717 (internal quota-tion marks omitted; emphasis added).

III

Petitioners’ reliance on Massachusetts’sloss of coastal land as their injury in factfor standing purposes creates insurSmount-able543 problems for them with respect tocausation and redressability. To establishstanding, petitioners must show a causalconnection between that specific injuryand the lack of new motor vehicle green-house gas emission standards, and that thepromulgation of such standards would like-ly redress that injury. As is often thecase, the questions of causation and re-dressability overlap. See Allen, 468 U.S.,at 753, n. 19, 104 S.Ct. 3315 (observingthat the two requirements were ‘‘initially

articulated by this Court as two facets of asingle causation requirement’’ (internalquotation marks omitted)). And impor-tantly, when a party is challenging theGovernment’s allegedly unlawful regula-tion, or lack of regulation, of a third party,satisfying the causation and redressabilityrequirements becomes ‘‘substantially moredifficult.’’ Defenders of Wildlife, 504 U.S.,at 562, 112 S.Ct. 2130 (internal quotationmarks omitted); see also Warth, supra, at504–505, 95 S.Ct. 2197.

Petitioners view the relationship be-tween their injuries and EPA’s failure topromulgate new motor vehicle greenhousegas emission standards as simple and di-rect: Domestic motor vehicles emit carbondioxide and other greenhouse gases.Worldwide emissions of greenhouse gasescontribute to global warming and thereforealso to petitioners’ alleged injuries. With-out the new vehicle standards, greenhousegas emissions—and therefore global warm-ing and its attendant harms—have beenhigher than they otherwise would havebeen; once EPA changes course, the trendwill be reversed.

The Court ignores the complexities ofglobal warming, and does so by now disre-garding the ‘‘particularized’’ injury it re-lied on in step one, and using the direnature of global warming itself as a boot-strap for finding causation and redressa-bility. First, it is important to recognizethe extent of the emissions at issue here.Because local greenhouse gas emissionsdisperse throughout the atmosphere andremain there for anywhere from 50 to 200years, it is global emissions data that arerelevant. See App. to Pet. for Cert. S 544A–73. According to one of petitioners’ decla-rations, domestic motor vehicles contributeabout 6 percent of global carbon dioxideemissions and 4 percent of global green-house gas emissions. Stdg.App. 232. Theamount of global emissions at issue here is


549 U.S. 545

smaller still; § 202(a)(1) of the Clean AirAct covers only new motor vehicles andnew motor vehicle engines, so petitioners’desired emission standards might reduceonly a fraction of 4 percent of global emis-sions.

This gets us only to the relevant green-house gas emissions; linking them to glob-al warming and ultimately to petitioners’alleged injuries next requires consider-ation of further complexities. As EPAexplained in its denial of petitioners’ re-quest for rulemaking,

‘‘predicting future climate change neces-sarily involves a complex web of econom-ic and physical factors including: ourability to predict future global anthropo-genic emissions of [greenhouse gases]and aerosols; the fate of these emissionsonce they enter the atmosphere (e.g.,what percentage are absorbed by vege-tation or are taken up by the oceans);the impact of those emissions that re-main in the atmosphere on the radiativeproperties of the atmosphere; changesin critically important climate feedbacks(e.g., changes in cloud cover and oceancirculation); changes in temperaturecharacteristics (e.g., average tempera-tures, shifts in daytime and eveningtemperatures); changes in other climaticparameters (e.g., shifts in precipitation,storms); and ultimately the impact ofsuch changes on human health and wel-fare (e.g., increases or decreases in agri-cultural productivity, human health im-pacts).’’ App. to Pet. for Cert. A–83through A–84.

Petitioners are never able to trace theiralleged injuries back through this complexweb to the fractional amount of globalemissions that might have been limitedwith EPA standards. In light of the bit-part domestic new motor vehiScle545 green-house gas emissions have played in whatpetitioners describe as a 150–year global

phenomenon, and the myriad additionalfactors bearing on petitioners’ alleged inju-ry—the loss of Massachusetts coastalland—the connection is far too speculativeto establish causation.

IV

Redressability is even more problematic.To the tenuous link between petitioners’alleged injury and the indeterminate frac-tional domestic emissions at issue here,add the fact that petitioners cannot mean-ingfully predict what will come of the 80percent of global greenhouse gas emissionsthat originate outside the United States.As the Court acknowledges, ‘‘developingcountries such as China and India arepoised to increase greenhouse gas emis-sions substantially over the next century,’’ante, at 1458, so the domestic emissions atissue here may become an increasinglymarginal portion of global emissions, andany decreases produced by petitioners’ de-sired standards are likely to be over-whelmed many times over by emissionsincreases elsewhere in the world.

Petitioners offer declarations attemptingto address this uncertainty, contendingthat ‘‘[i]f the U.S. takes steps to reducemotor vehicle emissions, other countriesare very likely to take similar actions re-garding their own motor vehicles usingtechnology developed in response to theU.S. program.’’ Stdg.App. 220; see alsoid., at 311–312. In other words, do notworry that other countries will contributefar more to global warming than will U.S.automobile emissions; someone is boundto invent something, and places like thePeople’s Republic of China or India willsurely require use of the new technology,regardless of cost. The Court previouslyhas explained that when the existence ofan element of standing ‘‘depends on theunfettered choices made by independentactors not before the courts and whose


exercise of broad and legitimate discretionthe courts cannot presume S 546either tocontrol or to predict,’’ a party must pres-ent facts supporting an assertion that theactor will proceed in such a manner. De-fenders of Wildlife, 504 U.S., at 562, 112S.Ct. 2130 (quoting ASARCO Inc. v. Kad-ish, 490 U.S. 605, 615, 109 S.Ct. 2037, 104L.Ed.2d 696 (1989) (opinion of KENNE-DY, J.); internal quotation marks omit-ted). The declarations’ conclusory (not tosay fanciful) statements do not even comeclose.

No matter, the Court reasons, becauseany decrease in domestic emissions will‘‘slow the pace of global emissions increas-es, no matter what happens elsewhere.’’Ante, at 1458. Every little bit helps, soMassachusetts can sue over any little bit.

The Court’s sleight of hand is in failingto link up the different elements of thethree-part standing test. What must belikely to be redressed is the particularinjury in fact. The injury the Court looksto is the asserted loss of land. The Courtcontends that regulating domestic motorvehicle emissions will reduce carbon diox-ide in the atmosphere, and therefore re-dress Massachusetts’s injury. But even ifregulation does reduce emissions—to someindeterminate degree, given events else-where in the world—the Court never ex-plains why that makes it likely that theinjury in fact—the loss of land—will beredressed. Schoolchildren know that akingdom might be lost ‘‘all for the want ofa horseshoe nail,’’ but ‘‘likely’’ redressabili-ty is a different matter. The realitiesmake it pure conjecture to suppose thatEPA regulation of new automobile emis-sions will likely prevent the loss of Massa-chusetts coastal land.

V

Petitioners’ difficulty in demonstratingcausation and redressability is not surpris-

ing given the evident mismatch betweenthe source of their alleged injury—cata-strophic global warming—and the narrowsubject matter of the Clean Air Act provi-sion at issue in this suit. The mismatchsuggests S 547that petitioners’ true goal forthis litigation may be more symbolic thananything else. The constitutional role ofthe courts, however, is to decide concretecases—not to serve as a convenient forumfor policy debates. See Valley ForgeChristian College v. Americans United forSeparation of Church and State, Inc., 454U.S. 464, 472, 102 S.Ct. 752, 70 L.Ed.2d700 (1982) (‘‘[Standing] tends to assurethat the legal questions presented to thecourt will be resolved, not in the rarifiedatmosphere of a debating society, but in aconcrete factual context conducive to a re-alistic appreciation of the consequences ofjudicial action’’).

When dealing with legal doctrinephrased in terms of what is ‘‘fairly’’ tracea-ble or ‘‘likely’’ to be redressed, it is per-haps not surprising that the matter is sub-ject to some debate. But in consideringhow loosely or rigorously to define thoseadverbs, it is vital to keep in mind thepurpose of the inquiry. The limitation ofthe judicial power to cases and controver-sies ‘‘is crucial in maintaining the tripartiteallocation of power set forth in the Consti-tution.’’ DaimlerChrysler, 547 U.S., at341, 126 S.Ct., at 1860–1861 (internal quo-tation marks omitted). In my view, theCourt today—addressing Article III’s‘‘core component of standing,’’ Defendersof Wildlife, supra, at 560, 112 S.Ct. 2130—fails to take this limitation seriously.

To be fair, it is not the first time theCourt has done so. Today’s decision re-calls the previous high-water mark of di-luted standing requirements, UnitedStates v. Students Challenging RegulatoryAgency Procedures (SCRAP), 412 U.S.669, 93 S.Ct. 2405, 37 L.Ed.2d 254 (1973).


549 U.S. 549

SCRAP involved ‘‘[p]robably the most at-tenuated injury conferring Art. III stand-ing’’ and ‘‘surely went to the very outerlimit of the law’’—until today. Whitmore,495 U.S., at 158–159, 110 S.Ct. 1717; seealso Lujan v. National Wildlife Federa-tion, 497 U.S. 871, 889, 110 S.Ct. 3177, 111L.Ed.2d 695 (1990) (SCRAP ‘‘has neversince been emulated by this Court’’). InSCRAP, the Court based an environmentalgroup’s standing to challenge a railroadfreight rate surcharge on the group’s alle-gation that S 548increases in railroad rateswould cause an increase in the use ofnonrecyclable goods, resulting in the in-creased need for natural resources to pro-duce such goods. According to the group,some of these resources might be takenfrom the Washington area, resulting inincreased refuse that might find its wayinto area parks, harming the group’s mem-bers. 412 U.S., at 688, 93 S.Ct. 2405.

Over time, SCRAP became emblematicnot of the looseness of Article III standingrequirements, but of how utterly manipula-ble they are if not taken seriously as amatter of judicial self-restraint. SCRAPmade standing seem a lawyer’s game,rather than a fundamental limitation en-suring that courts function as courts andnot intrude on the politically accountablebranches. Today’s decision is SCRAP fora new generation.2

Perhaps the Court recognizes as much.How else to explain its need to devise anew doctrine of state standing to support

its result? The good news is that theCourt’s ‘‘special solicitude’’ for Massachu-setts limits the future applicability of thediluted standing requirements applied inthis case. The bad news is that theCourt’s self-professed relaxation of thoseArticle III requirements has caused us totransgress ‘‘the proper—and properly lim-ited—role of the courts in a S 549democraticsociety.’’ Allen, 468 U.S., at 750, 104 S.Ct.3315 (internal quotation marks omitted).

I respectfully dissent.

Justice SCALIA, with whom THECHIEF JUSTICE, Justice THOMAS, andJustice ALITO join, dissenting.

I join THE CHIEF JUSTICE’s opinionin full, and would hold that this Court hasno jurisdiction to decide this case becausepetitioners lack standing. The Court hav-ing decided otherwise, it is appropriate forme to note my dissent on the merits.

I

A

The provision of law at the heart of thiscase is § 202(a)(1) of the Clean Air Act(CAA or Act), which provides that theAdministrator of the Environmental Pro-tection Agency (EPA) ‘‘shall by regulationprescribe TTT standards applicable to theemission of any air pollutant from anyclass or classes of new motor vehicles ornew motor vehicle engines, which in his

2. The difficulty with SCRAP, and the reason ithas not been followed, is not the portion citedby the Court. See ante, at 1458 – 1459, n. 24.Rather, it is the attenuated nature of the injurythere, and here, that is so troubling. Even inSCRAP, the Court noted that what was re-quired was ‘‘something more than an inge-nious academic exercise in the conceivable,’’412 U.S., at 688, 93 S.Ct. 2405, and we havesince understood the allegation there to havebeen ‘‘that the string of occurrences allegedwould happen immediately,’’ Whitmore v. Ar-

kansas, 495 U.S. 149, 159, 110 S.Ct. 1717,109 L.Ed.2d 135 (1990) (emphasis added).That is hardly the case here.

The Court says it is ‘‘quite wrong’’ to com-pare petitioners’ challenging ‘‘EPA’s parsimo-nious construction of the Clean Air Act to amere ‘lawyer’s game.’ ’’ Ante, at 1458 –1459, n. 24. Of course it is not the legalchallenge that is merely ‘‘an ingenious aca-demic exercise in the conceivable,’’ SCRAP,supra, at 688, 93 S.Ct. 2405, but the asser-tions made in support of standing.


judgment cause, or contribute to, air pollu-tion which may reasonably be anticipatedto endanger public health or welfare.’’ 42U.S.C. § 7521(a)(1) (emphasis added). Asthe Court recognizes, the statute ‘‘condi-tion[s] the exercise of EPA’s authority onits formation of a ‘judgment.’ ’’ Ante, at1462. There is no dispute that the Admin-istrator has made no such judgment in thiscase. See ante, at 1463 (‘‘We need not anddo not reach the question whether on re-mand EPA must make an endangermentfinding’’); 68 Fed.Reg. 52929 (2003) (‘‘[N]oAdministrator has made a finding underany of the CAA’s regulatory provisionsthat CO2 meets the applicable statutorycriteria for regulation’’).

The question thus arises: Does anythingrequire the Administrator to make a‘‘judgment’’ whenever a petition for rule-making is filed? Without citation of thestatute or any other authority, the Courtsays yes. Why is that so? WhenS 550Congress wishes to make private actionforce an agency’s hand, it knows how to doso. See, e.g., Brock v. Pierce County, 476U.S. 253, 254–255, 106 S.Ct. 1834, 90L.Ed.2d 248 (1986) (discussing the Com-prehensive Employment and Training Act(CETA), 92 Stat. 1926, 29 U.S.C. § 816(b)(1976 ed., Supp. V), which ‘‘provide[d] thatthe Secretary of Labor ‘shall’ issue a finaldetermination as to the misuse of CETAfunds by a grant recipient within 120 daysafter receiving a complaint alleging suchmisuse’’). Where does the CAA say thatthe EPA Administrator is required tocome to a decision on this question when-ever a rulemaking petition is filed? TheCourt points to no such provision becausenone exists.

Instead, the Court invents a multiple-choice question that the EPA Administra-

tor must answer when a petition for rule-making is filed. The Administrator mustexercise his judgment in one of threeways: (a) by concluding that the pollutantdoes cause, or contribute to, air pollutionthat endangers public welfare (in whichcase EPA is required to regulate); (b) byconcluding that the pollutant does notcause, or contribute to, air pollution thatendangers public welfare (in which caseEPA is not required to regulate); or (c) by‘‘provid[ing] some reasonable explanationas to why it cannot or will not exercise itsdiscretion to determine whether’’ green-house gases endanger public welfare, ante,at 1462, (in which case EPA is not re-quired to regulate).

I am willing to assume, for the sake ofargument, that the Administrator’s discre-tion in this regard is not entirely unbound-ed—that if he has no reasonable basis fordeferring judgment he must grasp the net-tle at once. The Court, however, with nobasis in text or precedent, rejects all ofEPA’s stated ‘‘policy judgments’’ as not‘‘amount[ing] to a reasoned justification,’’ante, at 1463, effectively narrowing theuniverse of potential reasonable bases to asingle one: Judgment can be delayed onlyif the Administrator concludes that ‘‘thescientific uncertainty is [too] profound.’’Ibid. The Administrator is precluded fromconcluding for other reasons ‘‘that it wouldTTT be better not to regulate S 551at thistime.’’ Ibid.1 Such other reasons—perfect-ly valid reasons—were set forth in theAgency’s statement.

‘‘We do not believe TTT that it would beeither effective or appropriate for EPAto establish [greenhouse gas] standardsfor motor vehicles at this time. As de-scribed in detail below, the Presidenthas laid out a comprehensive approach

1. The Court’s way of putting it is, of course,not quite accurate. The issue is whether itwould be better to defer the decision about

whether to exercise judgment. This has theeffect of deferring regulation but is quite adifferent determination.


549 U.S. 553

to climate change that calls for near-term voluntary actions and incentivesalong with programs aimed at reducingscientific uncertainties and encouragingtechnological development so that thegovernment may effectively and effi-ciently address the climate change issueover the long term.

TTTTT

‘‘[E]stablishing [greenhouse gas] emis-sion standards for U.S. motor vehicles atthis time would TTT result in an ineffi-cient, piecemeal approach to addressingthe climate change issue. The U.S. mo-tor vehicle fleet is one of many sourcesof [greenhouse gas] emissions both hereand abroad, and different [greenhousegas] emission sources face differenttechnological and financial challenges inreducing emissions. A sensible regula-tory scheme would require that all sig-nificant sources and sinks of [green-house gas] emissions be considered indeciding how best to achieve any neededemission reductions.

‘‘Unilateral EPA regulation of motorvehicle [greenhouse gas] emissions couldalso weaken U.S. efforts to persuadedeveloping countries to reduce the[greenhouse gas] intensity of their econ-omies. Considering the large popula-tions and growing economies of somedeveloping countries, increases in their[greenhouse gas] emissions could quick-ly overwhelm the effects of[greenShouse552 gas] reduction measuresin developed countries. Any potentialbenefit of EPA regulation could be lostto the extent other nations decided to lettheir emissions significantly increase inview of U.S. emissions reductions. Una-voidably, climate change raises impor-tant foreign policy issues, and it is thePresident’s prerogative to addressthem.’’ 68 Fed.Reg. 52929–52931 (foot-note omitted).

The Court dismisses this analysis as‘‘rest[ing] on reasoning divorced from thestatutory text.’’ Ante, at 1462. ‘‘Whilethe statute does condition the exercise ofEPA’s authority on its formation of a‘judgment,’ TTT that judgment must relateto whether an air pollutant ‘cause[s], orcontribute[s] to, air pollution which mayreasonably be anticipated to endangerpublic health or welfare.’ ’’ Ibid. True butirrelevant. When the Administratormakes a judgment whether to regulategreenhouse gases, that judgment must re-late to whether they are air pollutants that‘‘cause, or contribute to, air pollution whichmay reasonably be anticipated to endangerpublic health or welfare.’’ 42 U.S.C.§ 7521(a)(1). But the statute says nothingat all about the reasons for which theAdministrator may defer making a judg-ment—the permissible reasons for decid-ing not to grapple with the issue at thepresent time. Thus, the various ‘‘policy’’rationales, ante, at 1463, that the Courtcriticizes are not ‘‘divorced from the statu-tory text,’’ ante, at 1462, except in thesense that the statutory text is silent, astexts are often silent about permissiblereasons for the exercise of agency discre-tion. The reasons EPA gave are surelyconsiderations executive agencies regular-ly take into account (and ought to take intoaccount) when deciding whether to consid-er entering a new field: the impact suchentry would have on other ExecutiveBranch programs and on foreign policy.There is no basis in law for the Court’simposed limitation.

EPA’s interpretation of the discretionconferred by the statutory reference to‘‘its judgment’’ is not only reasonable, S 553itis the most natural reading of the text.The Court nowhere explains why this in-terpretation is incorrect, let alone why it isnot entitled to deference under ChevronU.S.A. Inc. v. Natural Resources Defense


Council, Inc., 467 U.S. 837, 104 S.Ct. 2778,81 L.Ed.2d 694 (1984). As the Adminis-trator acted within the law in declining tomake a ‘‘judgment’’ for the policy reasonsabove set forth, I would uphold the deci-sion to deny the rulemaking petition onthat ground alone.

B

Even on the Court’s own terms, howev-er, the same conclusion follows. As men-tioned above, the Court gives EPA theoption of determining that the science istoo uncertain to allow it to form a ‘‘judg-ment’’ as to whether greenhouse gases en-danger public welfare. Attached to thisoption (on what basis is unclear) is anessay requirement: ‘‘If,’’ the Court says,‘‘the scientific uncertainty is so profoundthat it precludes EPA from making a rea-soned judgment as to whether greenhousegases contribute to global warming, EPAmust say so.’’ Ante, at 1463. But EPAhas said precisely that—and at greatlength, based on information contained in a2001 report by the National ResearchCouncil (NRC) entitled Climate ChangeScience: An Analysis of Some Key Ques-tions:

‘‘As the NRC noted in its report, con-centrations of [greenhouse gases(GHGs) ] are increasing in the atmo-sphere as a result of human activities(pp. 9–12). It also noted that ‘[a] di-verse array of evidence points to awarming of global surface air tempera-tures’ (p. 16). The report goes on tostate, however, that ‘[b]ecause of thelarge and still uncertain level of naturalvariability inherent in the climate recordand the uncertainties in the time histo-ries of the various forcing agents (andparticularly aerosols), a [causal] linkagebetween the buildup of [GHGs] in theatmosphere and the observed climatechanges during the 20th century cannot

be unequivocally established. The factthat the S 554magnitude of the observedwarming is large in comparison to natu-ral variability as simulated in climatemodels is suggestive of such a linkage,but it does not constitute proof of onebecause the model simulations could bedeficient in natural variability on thedecadal to century time scale’ (p. 17).

‘‘The NRC also observed that ‘there isconsiderable uncertainty in current un-derstanding of how the climate systemvaries naturally and reacts to emissionsof [GHGs] and aerosols’ (p. 1). As aresult of that uncertainty, the NRC cau-tioned that ‘current estimate of the mag-nitude of future warming should be re-garded as tentative and subject to futureadjustments (either upward or down-ward).’ Id. It further advised that ‘[r]e-ducing the wide range of uncertaintyinherent in current model predictions ofglobal climate change will require majoradvances in understanding and modelingof both (1) the factors that determineatmospheric concentrations of [GHGs]and aerosols and (2) the so-called ‘‘feed-backs’’ that determine the sensitivity ofthe climate system to a prescribed in-crease in [GHGs].’ Id.

‘‘The science of climate change is ex-traordinarily complex and still evolving.Although there have been substantialadvances in climate change science,there continue to be important uncer-tainties in our understanding of the fac-tors that may affect future climatechange and how it should be addressed.As the NRC explained, predicting futureclimate change necessarily involves acomplex web of economic and physicalfactors including: Our ability to predictfuture global anthropogenic emissions ofGHGs and aerosols; the fate of theseemissions once they enter the atmo-sphere (e.g., what percentage are ab-


549 U.S. 556

sorbed by vegetation or are taken up bythe oceans); the impact of those emis-sions that remain in the atmosphere onthe radiative properties of the at-mosSphere;555 changes in critically impor-tant climate feedbacks (e.g., changes incloud cover and ocean circulation);changes in temperature characteristics(e.g., average temperatures, shifts indaytime and evening temperatures);changes in other climatic parameters(e.g., shifts in precipitation, storms); andultimately the impact of such changes onhuman health and welfare (e.g., increas-es or decreases in agricultural produc-tivity, human health impacts). TheNRC noted, in particular, that ‘[t]he un-derstanding of the relationships betweenweather/climate and human health is inits infancy and therefore the health con-sequences of climate change are poorlyunderstood’ (p. 20). Substantial scienti-fic uncertainties limit our ability to as-sess each of these factors and to sepa-rate out those changes resulting fromnatural variability from those that aredirectly the result of increases in anthro-pogenic GHGs.

‘‘Reducing the wide range of uncer-tainty inherent in current model predic-tions will require major advances in un-derstanding and modeling of the factorsthat determine atmospheric concentra-tions of [GHGs] and aerosols, and theprocesses that determine the sensitivityof the climate system.’’ 68 Fed.Reg.52930.

I simply cannot conceive of what else theCourt would like EPA to say.

II

A

Even before reaching its discussion ofthe word ‘‘judgment,’’ the Court makesanother significant error when it concludesthat ‘‘§ 202(a)(1) of the Clean Air Act au-

thorizes EPA to regulate greenhouse gasemissions from new motor vehicles in theevent that it forms a ‘judgment’ that suchemissions contribute to climate change.’’Ante, at 1459 (emphasis added). For suchauthorization, the Court relies on S 556whatit calls ‘‘the Clean Air Act’s capacious defi-nition of ‘air pollutant.’ ’’ Ante, at 1460.

‘‘Air pollutant’’ is defined by the Act as‘‘any air pollution agent or combination ofsuch agents, including any physical, chemi-cal, TTT substance or matter which is emit-ted into or otherwise enters the ambientair.’’ 42 U.S.C. § 7602(g). The Court iscorrect that ‘‘[c]arbon dioxide, methane,nitrous oxide, and hydrofluorocarbons,’’ante, at 1462, fit within the second half ofthat definition: They are ‘‘physical, chemi-cal, TTT substance[s] or matter which [are]emitted into or otherwise ente[r] the am-bient air.’’ But the Court mistakenly be-lieves this to be the end of the analysis.In order to be an ‘‘air pollutant’’ under theAct’s definition, the ‘‘substance or matter[being] emitted into TTT the ambient air’’must also meet the first half of the defini-tion—namely, it must be an ‘‘air pollutionagent or combination of such agents.’’The Court simply pretends this half of thedefinition does not exist.

The Court’s analysis faithfully followsthe argument advanced by petitioners,which focuses on the word ‘‘including’’ inthe statutory definition of ‘‘air pollutant.’’See Brief for Petitioners 13–14. As thatargument goes, anything that follows theword ‘‘including’’ must necessarily be asubset of whatever precedes it. Thus, ifgreenhouse gases qualify under the phrasefollowing the word ‘‘including,’’ they mustqualify under the phrase preceding it.Since greenhouse gases come within thecapacious phrase ‘‘any physical, chemical,TTT substance or matter which is emittedinto or otherwise enters the ambient air,’’


they must also be ‘‘air pollution agent[s] orcombination[s] of such agents,’’ and there-fore meet the definition of ‘‘air pollu-tant[s].’’

That is certainly one possible interpreta-tion of the statutory definition. The word‘‘including’’ can indeed indicate that whatfollows will be an ‘‘illustrative’’ sampling ofthe general category that precedes theword. Federal Land Bank of St. Paul v.Bismarck Lumber Co., 314 U.S. 95, 100, 62S.Ct. 1, 86 L.Ed. 65 S 557(1941). Often, how-ever, the examples standing alone arebroader than the general category, andmust be viewed as limited in light of thatcategory. The Government provides ahelpful (and unanswered) example: ‘‘Thephrase ‘any American automobile, includ-ing any truck or minivan,’ would not natu-rally be construed to encompass a foreign-manufactured [truck or] minivan.’’ Brieffor Federal Respondent 34. The generalprinciple enunciated—that the speaker istalking about American automobiles—car-ries forward to the illustrative examples(trucks and minivans), and limits them ac-cordingly, even though in isolation theyare broader. Congress often uses theword ‘‘including’’ in this manner. In 28U.S.C. § 1782(a), for example, it refers to‘‘a proceeding in a foreign or internationaltribunal, including criminal investigationsconducted before formal accusation.’’ Cer-tainly this provision would not encompasscriminal investigations underway in a do-mestic tribunal. See also, e.g., 2 U.S.C.§ 54(a) (‘‘The Clerk of the House of Rep-resentatives shall, at the request of aMember of the House of Representatives,furnish to the Member, for official useonly, one set of a privately published anno-

tated version of the United States Code,including supplements and pocket parts’’);22 U.S.C. § 2304(b)(1) (‘‘the relevant find-ings of appropriate international organiza-tions, including nongovernmental organiza-tions’’).

In short, the word ‘‘including’’ does notrequire the Court’s (or the petitioners’)result. It is perfectly reasonable to viewthe definition of ‘‘air pollutant’’ in its en-tirety: An air pollutant can be ‘‘any physi-cal, chemical, TTT substance or matterwhich is emitted into or otherwise entersthe ambient air,’’ but only if it retains thegeneral characteristic of being an ‘‘air pol-lution agent or combination of suchagents.’’ This is precisely the conclusionEPA reached: ‘‘[A] substance does notmeet the CAA definition of ‘air pollutant’simply because it is a ‘physical, chemical,TTT substance or matter which is emittedinto or otherwise enters the ambient air.’It must S 558also be an ‘air pollution agent.’ ’’68 Fed.Reg. 52929, n. 3. See also id., at52928 (‘‘The root of the definition indicatesthat for a substance to be an ‘air pollutant,’it must be an ‘agent’ of ‘air pollution’ ’’).Once again, in the face of textual ambigui-ty, the Court’s application of Chevron def-erence to EPA’s interpretation of the word‘‘including’’ is nowhere to be found.2 Evi-dently, the Court defers only to those rea-sonable interpretations that it favors.

B

Using (as we ought to) EPA’s interpre-tation of the definition of ‘‘air pollutant,’’we must next determine whether green-house gases are ‘‘agent[s]’’ of ‘‘air pollu-tion.’’ If so, the statute would authorize

2. Not only is EPA’s interpretation reasonable,it is far more plausible than the Court’s alter-native. As the Court correctly points out, ‘‘allairborne compounds of whatever stripe,’’ante, at 1460, would qualify as ‘‘physical,chemical, TTT substance[s] or matter which

[are] emitted into or otherwise ente[r] theambient air,’’ 42 U.S.C. § 7602(g). It followsthat everything airborne, from Frisbees to fla-tulence, qualifies as an ‘‘air pollutant.’’ Thisreading of the statute defies common sense.


549 U.S. 560

regulation; if not, EPA would lack authori-ty.

Unlike ‘‘air pollutants,’’ the term ‘‘airpollution’’ is not itself defined by the CAA;thus, once again we must accept EPA’sinterpretation of that ambiguous term,provided its interpretation is a ‘‘permissi-ble construction of the statute.’’ Chevron,467 U.S., at 843, 104 S.Ct. 2778. In thiscase, the petition for rulemaking askedEPA for ‘‘regulation of [greenhouse gas]emissions from motor vehicles to reducethe risk of global climate change.’’ 68Fed.Reg. 52925. Thus, in deciding wheth-er it had authority to regulate, EPA had todetermine whether the concentration ofgreenhouse gases assertedly responsiblefor ‘‘global climate change’’ qualifies as‘‘air pollution.’’ EPA began with the com-monsense observation that the ‘‘[p]roblemsassociated with atmospheric concentrationsS 559of CO2,’’ id., at 52927, bear little resem-blance to what would naturally be termed‘‘air pollution’’:

‘‘EPA’s prior use of the CAA’s generalregulatory provisions provides an impor-tant context. Since the inception of theAct, EPA has used these provisions toaddress air pollution problems that oc-cur primarily at ground level or near thesurface of the earth. For example, na-tional ambient air quality standards(NAAQS) established under CAA sec-tion 109 address concentrations of sub-stances in the ambient air and the relat-ed public health and welfare problems.This has meant setting NAAQS for con-centrations of ozone, carbon monoxide,particulate matter and other substancesin the air near the surface of the earth,not higher in the atmosphere TTT. CO2,by contrast, is fairly consistent in con-centration throughout the world’s atmo-sphere up to approximately the lowerstratosphere.’’ Id., at 52926–52927.

In other words, regulating the buildup ofCO2 and other greenhouse gases in theupper reaches of the atmosphere, which isalleged to be causing global climatechange, is not akin to regulating the con-centration of some substance that is pollut-ing the air.

We need look no further than the dictio-nary for confirmation that this interpreta-tion of ‘‘air pollution’’ is eminently reason-able. The definition of ‘‘pollute,’’ ofcourse, is ‘‘[t]o make or render impure orunclean.’’ Webster’s New InternationalDictionary 1910 (2d ed.1949). And thefirst three definitions of ‘‘air’’ are as fol-lows: (1) ‘‘[t]he invisible, odorless, andtasteless mixture of gases which surroundsthe earth’’; (2) ‘‘[t]he body of the earth’satmosphere; esp., the part of it near theearth, as distinguished from the upperrarefied part’’; (3) ‘‘[a] portion of air or ofthe air considered with respect to physicalcharacteristics or as affecting theS 560senses.’’ Id., at 54. EPA’s conceptionof ‘‘air pollution’’—focusing on impuritiesin the ‘‘ambient air’’ ‘‘at ground level ornear the surface of the earth’’—is perfectlyconsistent with the natural meaning of thatterm.

In the end, EPA concluded that since‘‘CAA authorization to regulate is general-ly based on a finding that an air pollutantcauses or contributes to air pollution,’’ 68Fed.Reg. 52928, the concentrations of CO2

and other greenhouse gases allegedly af-fecting the global climate are beyond thescope of CAA’s authorization to regulate.‘‘[T]he term ‘air pollution’ as used in theregulatory provisions cannot be interpret-ed to encompass global climate change.’’Ibid. Once again, the Court utterly fails toexplain why this interpretation is incor-rect, let alone so unreasonable as to beunworthy 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 amalleable statute giving broad discretion,not to us but to an executive agency. Nomatter how important the underlying poli-cy issues at stake, this Court has no busi-ness substituting its own desired outcomefor the reasoned judgment of the responsi-ble agency.

,

549 U.S. 1328, 549 U.S. 1329,167 L.Ed.2d 578

Lakhdar BOUMEDIENEet al., Petitioners,

v.George W. BUSH, President of

the United States, et al.

Khaled A.F. Al Odah, next friend ofFawzi Khalid Abdullah Fahad

Al Odah, et al.,v.

United States et al.Nos. 06–1195, 06–1196.

April 2, 2007.

On petitions for writs of certiorari to theUnited States Court of Appeals for theDistrict of Columbia Circuit.

Seth P. Waxman, Wilmer, Cutler, Pick-ering, Hale and Dorr LLP, Washington,DC, for Petitioners.

Paul D. Clement, Solicitor General,United States Department of Justice,Washington, DC, for Respondents.

The petitions for writs of certiorari aredenied.

Statement of Justice STEVENS andJustice KENNEDY respecting the denialof certiorari.

S 1329Despite the obvious importance ofthe issues raised in these cases, we are

persuaded that traditional rules governingour decision of constitutional questions, seeAshwander v. TVA, 297 U.S. 288, 341, 56S.Ct. 466, 80 L.Ed. 688 (1936) (Brandeis,J., concurring), and our practice of requir-ing the exhaustion of available remedies asa precondition to accepting jurisdictionover applications for the writ of habeascorpus, cf. Ex parte Hawk, 321 U.S. 114,64 S.Ct. 448, 88 L.Ed. 572 (1944) (percuriam), make it appropriate to denythese petitions at this time. However,‘‘[t]his Court has frequently recognizedthat the policy underlying the exhaustion-of-remedies doctrine does not require theexhaustion of inadequate remedies.’’ Mar-ino v. Ragen, 332 U.S. 561, 570, n. 12, 68S.Ct. 240, 92 L.Ed. 170 (1947) (Rutledge,J., concurring). If petitioners later seek toestablish that the Government has unrea-sonably delayed proceedings under the De-tainee Treatment Act of 2005, Tit. X, 119Stat. 2739, or some other and ongoinginjury, alternative means exist for us toconsider our jurisdiction over the allega-tions made by petitioners before the Courtof Appeals. See 28 U.S.C. §§ 1651(a),2241. Were the Government to take addi-tional steps to prejudice the position ofpetitioners in seeking review in this Court,‘‘courts of competent jurisdiction,’’ includ-ing this Court, ‘‘should act promptly toensure that the office and purposes of thewrit of habeas corpus are not compro-mised.’’ Padilla v. Hanft, 547 U.S. 1062,1064, 126 S.Ct. 1649, 164 L.Ed.2d 409(2006) (Kennedy, J., concurring in denial ofcertiorari). And as always, denial of cer-tiorari does not constitute an expression ofany opinion on the merits. See Rasul v.Bush, 542 U.S. 466, 480–481, 124 S.Ct.2686, 159 L.Ed.2d 548 (2004) (majorityopinion of STEVENS, J.); id., at 487, 124S.Ct. 2686 (KENNEDY, J., concurring injudgment).

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