Cm MA v. EPA ( 2005 )


Menu:
  •  United States Court of Appeals
    FOR THE DISTRICT OF COLUMBIA CIRCUIT
    Argued April 8, 2005                      Decided July 15, 2005
    Reissued September 13, 2005
    No. 03-1361
    COMMONWEALTH OF MASSACHUSETTS, ET AL.,
    PETITIONERS
    v.
    ENVIRONMENTAL PROTECTION AGENCY,
    RESPONDENT
    ALLIANCE OF AUTOMOBILE MANUFACTURERS, ET AL.,
    INTERVENORS
    Consolidated with Nos.
    03-1362, 03-1363, 03-1364, 03-1365, 03-1366, 03-1367,
    03-1368
    On Petitions for Review of an Order of the
    Environmental Protection Agency
    James R. Milkey and Howard Fox argued the cause for
    petitioners. With them on the briefs were Thomas F. Reilly,
    Attorney General, Attorney General’s Office of the
    Commonwealth of Massachusetts, William L. Pardee, Assistant
    Attorney General, Joseph Mendelson, III, David Bookbinder,
    Bill Lockyer, Attorney General, Attorney General’s Office of the
    2
    State of California, Nicholas Stern and Marc N. Melnick, Deputy
    Attorneys General, David Doniger, Richard Blumenthal,
    Attorney General, Attorney General’s Office of the State of
    Connecticut, Kimberly Massicotte and Matthew Levine,
    Assistant Attorneys General, Peter C. Harvey, Attorney General,
    Attorney General’s Office of the State of New Jersey, Stefanie
    A. Brand, Deputy Attorney General, Hardy Myers, Attorney
    General, Attorney General’s Office of the State of Oregon,
    Philip Schradle, Special Counsel, Lisa Madigan, Attorney
    General, Attorney General’s Office of the State of Illinois, Gary
    Feinerman, Solicitor General, Gerald T. Karr and Thomas E.
    Davis, Assistant Attorneys General, Patricia A. Madrid,
    Attorney General, Attorney General’s Office of the State of New
    Mexico, Stuart M. Bluestone, Deputy Attorney General, Patrick
    C. Lynch, Attorney General, Attorney General’s Office of the
    State of Rhode Island, Tricia K. Jedele, Special Assistant, G.
    Steven Rowe, Attorney General, Attorney General’s Office of
    the State of Maine, Gerald D. Reid, Assistant Attorney General,
    Eliot Spitzer, Attorney General, Attorney General’s Office of the
    State of New York, Peter Lehner and J. Jared Snyder, Assistant
    Attorneys General, William H. Sorrell, Attorney General,
    Attorney General’s Office of the State of Vermont, Erick Titrud
    and Kevin O. Leske, Assistant Attorneys General, Rob
    McKenna, Attorney General, Attorney General’s Office of the
    State of Washington, David K. Mears, Assistant Attorney
    General, John Hogrogian, Assistant Corporation Counsel,
    Corporation Counsel of the City of New York, Julie M.
    Anderson, Fiti A. Sunia, Attorney General, Attorney General’s
    Office of the American Samoa, Ralph S. Tyler, III, Solicitor,
    City of Baltimore, William Phelan, Jr., Counsel, James B. Tripp,
    Robert J. Spagnoletti, Attorney General, Attorney General’s
    Office of the District of Columbia, Edward E. Schwab, Deputy
    Attorney General, and Donna M. Murasky, Senior Litigation
    Counsel.
    3
    Rebecca L. Bernard and Jeremy Kyle Kinner were on the
    brief of amici curiae Indigenous Environmental Network,
    REDOIL and Physicians for Social Responsibility.
    Jeffrey Bossert Clark, Deputy Assistant Attorney General,
    U.S. Department of Justice, argued the cause for respondent.
    With him on the brief were Thomas L. Sansonetti, Assistant
    Attorney General, Jon M. Lipshultz, Attorney, Ann R. Klee,
    General Counsel, U.S. Environmental Protection Agency, and
    John T. Hannon and Nancy Ketcham-Colwill, Counsel.
    Neil D. Gordon, Assistant Attorney General, Attorney
    General’s Office of the State of Michigan, argued the cause for
    intervenors States of Michigan, et al., and amicus curiae State
    of Indiana. With him on the briefs were Alan F. Hoffman,
    Assistant Attorney General, Jane E. Atwood, Assistant Attorney
    General, Attorney General’s Office of the State of Texas,
    Douglas Conde, Deputy Attorney General, Attorney General’s
    Office of the State of Idaho, Charles M. Carvell, Assistant
    Attorney General, Attorney General’s Office of the State of
    North Dakota, Fred Nelson, Assistant Attorney General,
    Attorney General’s Office of the State of Utah, Roxanne Giedd,
    Deputy Attorney General, Attorney General’s Office of the State
    of South Dakota, Steven E. Mulder, Assistant Attorney General,
    Attorney General’s Office of the State of Alaska, David W.
    Davies, Attorney, Attorney General’s Office of the State of
    Kansas, David D. Cookson and Natalee J. Hart, Assistant
    Attorneys General, Attorney General’s Office of the State of
    Nebraska, Dale T. Vitale, Senior Deputy Attorney General,
    Attorney General’s Office of the State of Ohio, and Thomas M.
    Fisher, Special Counsel, Attorney General’s Office of the State
    of Indiana.
    Norman W. Fichthorn, Allison D. Wood, William A.
    Anderson, II., Eric P. Gotting, Russell S. Frye, John L.
    4
    Wittenborn, William L. Fang, Dell E. Perelman, Leslie A. Hulse,
    Richard Wasserstrom, Harry M. Ng, Ralph J. Colleli, Jr., Jan S.
    Amundson, Quentin Riegel, Robin S. Conrad, John T. Whatley,
    Julie C. Becker, Douglas I. Greenhaus, Jed R. Mandel, Timothy
    A. French, Robert G. Slaughter, Mark J. Washko, and Nick
    Goldstein were on the brief of industry intervenors in support of
    respondent.
    Daniel J. Popeo, Paul D. Kamenar, Peter Glaser, and
    Douglas A. Henderson were on the brief of amicus curiae
    Washington Legal Foundation in support of respondent.
    Edward W. Warren and Eric B. Wolff were on the brief of
    amicus curiae John D. Dingell (D-Michgan) in support of denial
    of petitions for review.
    Before: SENTELLE, RANDOLPH, and TATEL, Circuit Judges.
    Judgment of the Court filed by Circuit Judge RANDOLPH.
    Opinion filed by Circuit Judge RANDOLPH.
    Opinion dissenting in part and concurring in the judgment
    filed by Circuit Judge SENTELLE.
    Opinion dissenting in Nos. 03-1361, 03-1362, 03-1363, and
    03-1364 filed by Circuit Judge TATEL.
    RANDOLPH, Circuit Judge: Petitioners are twelve states,
    three cities, an American territory, and numerous environmental
    organizations. They are opposed by the Environmental
    Protection Agency as respondent, and ten states and several
    trade associations as intervenors. The controversy is about
    EPA’s denial of a petition asking it to regulate carbon dioxide
    (CO2) and other greenhouse gas emissions from new motor
    5
    vehicles under § 202(a)(1) of the Clean Air Act, 
    42 U.S.C. § 7521
    (a)(1). EPA concluded that it did not have statutory
    authority to regulate greenhouse gas emissions from motor
    vehicles and that, even if it did, it would not exercise the
    authority at this time. 
    68 Fed. Reg. 52,922
     (Sept. 8, 2003).
    I.
    We should say a few words about our jurisdiction under the
    Clean Air Act to review an EPA denial of a petition for
    rulemaking. Section 307(b)(1), 
    42 U.S.C. § 7607
    (b)(1), gives
    this court exclusive jurisdiction over “nationally applicable
    regulations promulgated, or final action taken, by the
    Administrator” under chapter 85 of the Act. The district courts,
    on the other hand, have jurisdiction over citizen suits to compel
    EPA to perform nondiscretionary acts or duties. 
    42 U.S.C. § 7604
    (a)(2); see Sierra Club v. Thomas, 
    828 F.2d 783
    , 787-92
    (D.C. Cir. 1987). Because EPA refused to promulgate
    “nationally applicable regulations” after being asked to do so,
    we have jurisdiction only if EPA thereby engaged in “final
    action.” We can be sure that its denial of the rulemaking
    petition was “final.” But did this constitute agency “action”?
    To answer that question we must consult the Administrative
    Procedure Act -- specifically 
    5 U.S.C. § 551
    (13). The term
    “action” in § 307(b)(1) of the Clean Air Act, like the term
    “final,” carries its traditional meaning in administrative law. See
    Whitman v. Am. Trucking Ass’ns, 
    531 U.S. 457
    , 478 (2001);
    Indep. Equip. Dealers Ass’n v. EPA, 
    372 F.3d 420
    , 428 (D.C.
    Cir. 2004); Sierra Club v. Gorsuch, 
    715 F.2d 653
    , 656-57 (D.C.
    Cir. 1983). Section 551(13) of the APA defines “agency action”
    as “the whole or a part of an agency rule, order, license,
    sanction, relief, or the equivalent or denial thereof, or failure to
    act” (italics added). While § 307 of the Clean Air Act makes
    several APA provisions inapplicable -- namely, 
    5 U.S.C. §§ 553
    -
    557 & 706 -- APA § 551 is not among them. EPA’s denial of
    6
    the rulemaking petition was therefore “final action,” and since
    the petition sought regulations national in scope, § 307(b)(1)
    confers jurisdiction on this court to hear these consolidated
    cases.
    Another, related, point needs to be mentioned. Several of
    the petitions for judicial review treated a memorandum of EPA’s
    General Counsel, Robert Fabricant, as “final action taken, by the
    Administrator” under § 307(b)(1). The memorandum, dated
    August 28, 2003, and addressed to the EPA Administrator, was
    entitled “EPA’s Authority to Impose Mandatory Controls to
    Address Global Climate Change under the Clean Air Act.” The
    General Counsel, after analyzing § 202(a)(1) of the Clean Air
    Act, and other legislative and executive actions, stated his belief
    that the Act “does not authorize regulation to address global
    climate change.”          He therefore withdrew a contrary
    memorandum issued in 1998 by one of his predecessors.
    The Fabricant memorandum, consisting of legal advice to
    the EPA Administrator, did not in itself constitute “final action”
    of the Administrator. To be sure, the Administrator adopted the
    “General Counsel’s opinion” and relied on its analysis as one of
    the alternative grounds for rejecting the rulemaking petition.
    See 68 Fed. Reg. at 52,925. The Administrator’s explanation
    incorporated many of the memorandum’s passages verbatim,
    rephrased and reordered others, and expanded on the General
    Counsel’s reasoning. Still, it is the Administrator’s denial of the
    rulemaking petition, with the accompanying explanation, that
    represents the “final action” of the Administrator subject to
    judicial review under § 307(b)(1). The significance of the
    General Counsel’s opinion, as set forth in his memorandum, is
    the Administrator’s reliance on his reasoning in deciding the
    matter now before us.
    7
    There is an additional jurisdictional issue presented, but not
    under the Clean Air Act. EPA claims that petitioners lack
    standing under Article III of the Constitution. Standing exists
    only if the complainant has suffered an injury in fact, fairly
    traceable to the challenged action, and likely to be redressed by
    a favorable decision. See Lujan v. Defenders of Wildlife, 
    504 U.S. 555
    , 560 (1992). EPA’s argument is that petitioners have
    not “adequately demonstrated” two elements of standing: that
    their alleged injuries were “caused by EPA’s decision not to
    regulate emissions of greenhouse gases from mobile sources”;
    and that their injuries “can be redressed by a decision in their
    favor” by this court. Brief for Respondent at 16.
    In anticipation of this argument, petitioners filed two
    volumes of declarations with the court, some containing lengthy
    exhibits. The declarations, from scientists, engineers, state
    officials, homeowners, users of the nation’s recreational
    resources, and other individuals, predict catastrophic
    consequences from global warming caused by greenhouse gases,
    including loss of or damage to state and private property,
    frequent intense storm surge floods, and increased health care
    costs. Brief for Petitioners at 2-4.
    For the causation and redressability aspects of standing,
    petitioners cite two of their declarations. One, from a
    climatologist, states that reductions in CO2 and other greenhouse
    gases from vehicles in the United States would alone have a
    meaningful impact and would “delay and moderate many of the
    adverse impacts of global warming.” He adds that if EPA took
    action to reduce such emissions, other countries would likely
    follow suit. The climatologist bases his predictions about future
    climate change on climate models and on “quantitative scenarios
    generated by the IPCC” -- the Intergovernmental Panel on
    Climate Change, established in 1988 by the United Nations and
    the World Meteorological Organization. The other declaration
    8
    is from a mechanical engineer. He states that, on the basis of his
    experience with controlling other pollutants, there is “no doubt
    that establishing emissions standards for pollutants that
    contribute to global warming would lead to investment in
    developing improved technologies to reduce those emissions
    from motor vehicles, and that successful technologies would
    gradually be mandated by other countries around the world.”
    We have held that, to establish standing, a petitioner
    challenging agency action has the same burden of production as
    “a plaintiff moving for summary judgment in the district court:
    it must support each element of its claim to standing ‘by
    affidavit or other evidence.’” Sierra Club v. EPA, 
    292 F.3d 895
    ,
    899 (D.C. Cir. 2002) (quoting Lujan, 
    504 U.S. at 561
    ).
    Petitioners’ declarations do “support each element” of standing.
    But supporting an allegation is one thing; proving an allegation
    is quite another. Lujan holds that when a plaintiff’s standing is
    challenged in a motion for summary judgment, the plaintiff
    “must ‘set forth’ by affidavit or other evidence ‘specific facts,’
    Fed. Rule Civ. Proc. 56(e), which for purposes of the summary
    judgment motion will be taken as true.” 
    504 U.S. at 561
    . If we
    were to analogize the situation here to one in which EPA filed
    such a summary judgment motion, we would conclude that
    petitioners had submitted enough evidence raising genuine
    issues of material fact to defeat the motion. See FED. R. CIV. P.
    56©. But Lujan goes on to hold that at “the final stage” the
    evidence plaintiff presented at summary judgment “(if
    controverted) must be ‘supported adequately by the evidence
    adduced at trial.’” 
    504 U.S. at 561
     (quoting Gladstone, Realtors
    v. Village of Bellwood, 
    441 U.S. 91
    , 115 n.31 (1979)). One
    might say that in this case we are at the “final stage.” But the
    analogy is not entirely apt. As an appellate court we do not
    conduct evidentiary hearings in order to make findings of fact.
    This is why, when Sierra Club spoke of “other evidence”
    relating to standing, the court had in mind evidence presented to
    9
    the agency. 
    292 F.3d at 899
    . Here, the administrative record
    contains a wealth of such “other evidence,” and some of it
    contradicts petitioners’ claim that greenhouse gas emissions
    from new motor vehicles have caused or will cause a significant
    change in the global climate. That is partly why EPA decided
    not to regulate at this time.
    Steel Co. v. Citizens for a Better Environment, 
    523 U.S. 83
    (1998), instructs federal courts to resolve Article III standing
    questions before proceeding to the merits of a case. The
    combination of Lujan, Steel Co., and the factual overlap of the
    standing issues with EPA’s justifications for not regulating
    greenhouse gases present us with three options. The first is to
    refer the standing issues to a special master for a factual
    determination. This would be, as one commentator has
    suggested, “folly.” 13A CHARLES A. WRIGHT ET AL., FEDERAL
    PRACTICE AND PROCEDURE 2D § 3531.15, at 101 (1984). Such
    a proceeding would largely duplicate the proceedings on the
    rulemaking petition and to no good end. Another option would
    be to remand to EPA for a factual determination of causation
    and redressability. That too would make no sense. For one
    thing, judgments about standing are the responsibility of the
    federal courts. For another, EPA has already reached a decision
    about the state of the evidence regarding global warming from
    greenhouse gases. The third option is to proceed to the merits
    with respect to EPA’s alternative decision not to regulate on the
    grounds, among others, that the effect of greenhouse gases on
    climate is unclear and that models used to predict climate
    change might not be accurate.
    We have decided to follow the third course. Steel Co.
    endorses this approach with respect to questions of statutory
    standing. The Court explained that “the merits inquiry and the
    statutory standing inquiry often overlap” and “are sometimes
    identical, so that it would be exceedingly artificial to draw a
    10
    distinction between the two.” 
    523 U.S. at
    97 n.2. The Court’s
    distinction of Article III standing cases rested on the premise
    that there would be no such overlap and that the issue of Article
    III standing would be entirely separate from the merits. 
    Id.
     The
    Court did not say what the proper order of decision should be
    when, as in this case, that premise does not hold. In this highly
    unusual circumstance -- encountered for the first time in this
    court -- we will follow the statutory standing cases. We will
    therefore assume arguendo that EPA has statutory authority to
    regulate greenhouse gases from new motor vehicles.1 The
    question we address is whether EPA properly declined to
    exercise that authority.
    II.
    Greenhouse gases trap energy, much like the glass panels of
    a greenhouse. The earth’s surface is warmed by absorbing solar
    energy (visible light). The earth, in turn, radiates infrared energy
    (heat) back into space. A portion of the infrared radiation is
    trapped by greenhouse gas molecules, resulting in additional
    warming of the lower atmosphere and the earth’s surface. This
    “greenhouse effect” is a natural phenomenon, without which the
    planet would be significantly colder and life as we know it
    would not be possible. EPA, Global Warming -- Climate, at
    http://yosemite.epa.gov/oar/globalwarming.nsf/content/climat
    e.html.
    1
    Relying on FDA v. Brown & Williamson Tobacco Corp., 
    529 U.S. 120
     (2000), EPA concluded that in light of the enormous
    economic and political consequences of regulating greenhouse gas
    emissions, Congress would have been far more specific if it had
    intended to authorize EPA to regulate the subject under § 202(a)(1) of
    the Clean Air Act. 58 Fed. Reg. at 52,928. We express no view on
    the validity of EPA’s analysis.
    11
    Petitioners sought to have EPA regulate, under § 202(a)(1)
    of the Clean Air Act, carbon dioxide (CO2), and three other
    greenhouse gases: methane (CH4), nitrous oxide (N2O), and
    hydrofluorocarbons (HFCs).2 In response to EPA’s request for
    public comments on the 1999 petition for rulemaking, the
    agency received nearly 50,000 submissions. 68 Fed. Reg. at
    52,924. Most were short expressions of support for the petition;
    many were nearly identical. Id. The comment period closed in
    May 2001. In the same month, the White House requested the
    National Academy of Sciences to assist the Administration in its
    review of climate change policy. The Academy “is a private,
    nonprofit, self-perpetuating society of distinguished scholars
    engaged in scientific and engineering research . . . .” NATIONAL
    RESEARCH COUNCIL, CLIMATE CHANGE SCIENCE: AN ANALYSIS
    OF SOME OF THE KEY QUESTIONS, preface (2001). Under its
    congressional charter, issued in 1863, the Academy has a
    mandate to advise the federal government on scientific and
    technical matters when requested. The Academy’s principal
    operating agency for providing such advice is its National
    Research Council. Id.
    In denying the rulemaking petition, EPA found that the
    scientific comments petitioners and others submitted rested on
    information already in the public domain and did not add
    significantly to the body of knowledge available to the National
    Research Council when it prepared the report cited above. Since
    none of the comments caused EPA to question the Council’s
    report, EPA decided to rely on the Council’s “objective and
    independent assessment of the relevant science.” 68 Fed. Reg.
    at 52,930.
    2
    The rulemaking request and the papers submitted to this
    court focus on the effects of CO2.
    12
    The National Research Council concluded that “a causal
    linkage” between greenhouse gas emissions and global warming
    “cannot be unequivocally established.” NATIONAL RESEARCH
    COUNCIL, CLIMATE CHANGE SCIENCE, at 17. The earth
    regularly experiences climate cycles of global cooling, such as
    an ice age, followed by periods of global warming. Id. at 7.
    Global temperatures have risen since the industrial revolution,
    as have atmospheric levels of carbon dioxide. But an increase
    in carbon dioxide levels is not always accompanied by a
    corresponding rise in global temperatures. For example,
    although carbon dioxide levels increased steadily during the
    twentieth century, global temperatures decreased between 1946
    and 1975. Id. at 16. Considering this and other data, the
    National Research Council concluded that “there is considerable
    uncertainty in current understanding of how the climate system
    varies naturally and reacts to emissions of greenhouse gases.”
    Id. at 1. This uncertainty is compounded by the possibility for
    error inherent in the assumptions necessary to predict future
    climate change.3 And, as the National Research Council noted,
    3
    “As the NRC explained, predicting future climate change
    necessarily involves a complex web of economic and physical factors
    including: Our ability to predict future global anthropogenic emissions
    of GHGs and aerosols; the fate of these emissions once they enter the
    atmosphere (e.g., what percentage are absorbed by vegetation or are
    taken up by the oceans); the impact of those emissions that remain in
    the atmosphere on the radiative properties of the atmosphere; changes
    in critically important climate feedbacks (e.g., changes in cloud cover
    and ocean circulation); changes in temperature characteristics (e.g.,
    average temperatures, shifts in daytime and evening temperatures);
    changes in other climatic parameters (e.g., shifts in precipitation,
    storms); and ultimately the impact of such changes on human health
    and welfare (e.g., increases or decreases in agricultural productivity,
    human health impacts). The NRC noted, in particular, that ‘[t]he
    understanding of the relationships between weather/climate and
    human health is in its infancy and therefore the health consequences
    13
    past assumptions about effects of future greenhouse gas
    emissions have proven to be erroneously high. Id. at 19.
    Relying on Ethyl Corp. v. EPA, 
    541 F.2d 1
     (D.C. Cir. 1976)
    (en banc), petitioners challenge EPA’s decision to forego
    rulemaking “[u]ntil more is understood about the causes, extent
    and significance of climate change and the potential options for
    addressing it.” 68 Fed. Reg. at 52,931. In our view Ethyl
    supports EPA, not petitioners. Section 202(a)(1) directs the
    Administrator to regulate emissions that “in his judgment” “may
    reasonably be anticipated to endanger public health or welfare.”
    Section 202(a)(1) was not at issue in Ethyl; the court mentioned
    an earlier version of that provision, in a footnote, only by way
    of analogy. 
    541 F.2d at
    20 n.37. But what the court had to say
    about § 202(a)(1) is instructive. In requiring the EPA
    Administrator to make a threshold “judgment” about whether to
    regulate, § 202(a)(1) gives the Administrator considerable
    discretion. Id. Congress does not require the Administrator to
    exercise his discretion solely on the basis of his assessment of
    scientific evidence. Id. at 20. What the Ethyl court called
    “policy judgments” also may be taken into account. By this the
    court meant the sort of policy judgments Congress makes when
    it decides whether to enact legislation regulating a particular
    area. Id. at 26.
    The EPA Administrator’s analysis, although it did not
    mention Ethyl, is entirely consistent with the case. In addition
    to the scientific uncertainty about the causal effects of
    of climate change are poorly understood’ (p. 20). Substantial scientific
    uncertainties limit our ability to assess each of these factors and to
    separate out those changes resulting from natural variability from
    those that are directly the result of increases in anthropogenic GHGs.”
    68 Fed. Reg. at 52,930.
    14
    greenhouse gases on the future climate of the earth, the
    Administrator relied upon many “policy” considerations that, in
    his judgment, warranted regulatory forbearance at this time. 68
    Fed. Reg. at 52,929. New motor vehicles are but one of many
    sources of greenhouse gas emissions; promulgating regulations
    under § 202 would “result in an inefficient, piecemeal approach
    to the climate change issue.” 68 Fed. Reg. at 52,931. The
    Administrator expressed concern that unilateral regulation of
    U.S. motor vehicle emissions could weaken efforts to persuade
    developing countries to reduce the intensity of greenhouse gases
    thrown off by their economies. Id. Ongoing research into
    scientific uncertainties and the Administration’s programs to
    address climate change -- including voluntary emission
    reduction programs and initiatives with private entities to
    develop new technology -- also played a role in the
    Administrator’s decision not to regulate. 68 Fed. Reg. at
    52,931-33. The Administrator pointed to efforts to promote
    “fuel cell and hybrid vehicles” and ongoing efforts to develop
    “hydrogen as a primary fuel for cars and trucks.” 68 Fed. Reg.
    at 52,931. The Administrator also addressed the matter of
    remedies. Petitioners offered two ways to reduce CO2 from new
    motor vehicles: reduce gasoline consumption and improve tire
    performance. As to the first, the Department of Transportation
    -- the agency in charge of fuel efficiency standards -- recently
    issued new standards requiring greater fuel economy, as a result
    of which millions of metric tons of CO2 will never reach the
    stratosphere. Id. As to tire efficiency, EPA doubted its
    authority to regulate this subject as an “emission” of an air
    pollutant. Id. “With respect to the other [greenhouse gases] --
    CH4, N2O, and HFCs -- petitioners make no suggestion as to
    how those emissions might be reduced from motor vehicles.”
    Id.
    It is therefore not accurate to say, as petitioners do, that the
    EPA Administrator’s refusal to regulate rested entirely on
    15
    scientific uncertainty, or that EPA’s decision represented an
    “open-ended invocation of scientific uncertainty to justify
    refusing to regulate,” Brief for Petitioners at 51.              A
    “determination of endangerment to public health,” the court said
    in Ethyl, “is necessarily a question of policy that is to be based
    on an assessment of risks and that should not be bound by either
    the procedural or the substantive rigor proper for questions of
    fact.” Ethyl, 
    541 F.2d at 24
    . And as we have held, a reviewing
    court “will uphold agency conclusions based on policy
    judgments” “when an agency must resolve issues ‘on the
    frontiers of scientific knowledge.’” Envtl. Def. Fund v. EPA,
    
    598 F.2d 62
    , 82 (D.C. Cir. 1978).
    We thus hold that the EPA Administrator properly
    exercised his discretion under § 202(a)(1) in denying the petition
    for rulemaking. The petitions for review in Nos. 03-1365, 03-
    1366, 03-1367, and 03-1368 are dismissed, and the petitions for
    review in Nos. 03-1361, 03-1362, 03-1363, and 03-1364 are
    denied.
    So ordered.
    SENTELLE, Circuit Judge, dissenting in part and concurring
    in the judgment: As the majority’s opinion observes, courts of
    the United States must resolve jurisdictional questions, including
    “Article III standing questions, before proceeding to the merits
    of a case.” Opinion of Judge Randolph at 9 (citing Steel Co. v.
    Citizens for a Better Environment, 
    523 U.S. 83
     (1998)). As the
    majority further observes, “[s]tanding exists only if the
    complainant has suffered an injury in fact, fairly traceable to the
    challenged action, and likely to be redressed by a favorable
    decision.” 
    Id.
     at 6-7 (citing Lujan v. Defenders of Wildlife, 
    504 U.S. 555
    , 560 (1992)). EPA argues “that petitioners have not
    ‘adequately demonstrated’ two elements of standing: that their
    alleged injuries were ‘caused by EPA’s decision not to regulate
    emissions of greenhouse gases from mobile sources’; and that
    their injuries ‘can be redressed by a decision in their favor’ by
    this court.” Id. at 7 (quoting Brief for Respondent at 16). While
    I respect the majority’s thorough and accurate history of the
    precedents on the standing question, after consulting the same
    authorities I have come to a different conclusion. I conclude
    that EPA is correct in its assertion that the petitioners have not
    demonstrated the element of injury necessary to establish
    standing under Article III.
    I. Injury
    As the Supreme Court has stated quite directly and
    succinctly:
    It is an established principle that to entitle a private
    individual to invoke the judicial power to determine the
    validity of executive or legislative action he must show that
    he has sustained or is immediately in danger of sustaining
    a direct injury as the result of that action and it is not
    sufficient that he has merely a general interest common to
    all members of the public.
    2
    Ex Parte Levitt, 
    302 U.S. 633
     (1937) (citing Tyler v. Judges, 
    179 U.S. 405
    , 406 (1900); Southern Ry. Co. v. King, 
    217 U.S. 524
    ,
    534 (1910); Newman v. Frizzell, 
    238 U.S. 537
    , 549, 550 (1915);
    Fairchild v. Hughes, 
    258 U.S. 126
    , 129 (1922); Massachusetts
    v. Mellon, 
    262 U.S. 447
    , 488) (1923)).
    Thus, the courts “have consistently held that a plaintiff
    raising only a generally available grievance about government
    – claiming only harm to his and every citizen’s interest in proper
    application of the Constitution and laws, and seeking relief that
    no more directly and tangibly benefits him than it does the
    public at large – does not state an Article III case or
    controversy.” Lujan, 
    504 U.S. at 573
    . Or, as the Supreme Court
    has also put it, to establish Article III standing a “plaintiff must
    have suffered an ‘injury in fact’– an invasion of a legally
    protected interest which is (a) concrete and particularized . . .
    and (b) actual or imminent, not conjectural or hypothetical.” 
    Id. at 560
     (emphasis added; citations and internal quotation marks
    omitted). Most tellingly, the Supreme Court has specifically
    declared that “[b]y particularized, we mean that the injury must
    affect the plaintiff in a personal and individual way.” Id. at n.1.
    In the case before us, that is what the petitioners have not
    established. After plowing through their reams of affidavits and
    arguments, I am left with the unshaken conviction that they have
    alleged and shown no harm particularized to themselves. As we
    have observed in the context of determining standing even in a
    procedural case, in which the standards are perhaps more
    relaxed than in other cases, “in order to show that the interest
    asserted is more than a mere ‘general interest . . . common to all
    members of the public,’ the plaintiffs must show that the
    government act . . . will cause a distinct risk to a particularized
    interest of the plaintiff.” Florida Audubon Soc’y v. Bentsen, 
    94 F.3d 658
    , 664 (D.C. Cir. 1996).
    3
    Petitioners’ allegations and affidavits, and petitioners’
    argument and briefs, are all well made and sincere.
    Nonetheless, even in the light most favorable to the petitioners,
    in the end they come down to this: Emission of certain gases that
    the EPA is not regulating may cause an increase in the
    temperature of the earth – a phenomenon known as “global
    warming.” This is harmful to humanity at large. Petitioners are
    or represent segments of humanity at large. This would appear
    to me to be neither more nor less than the sort of general harm
    eschewed as insufficient to make out an Article III controversy
    by the Supreme Court and lower courts.
    The courts under Article III stand ready to adjudicate and
    redress the particularized injuries of plaintiffs, when all other
    elements of jurisdiction are present. But “when the plaintiff is
    not himself the object of the government action or inaction he
    challenges, [although] standing is not precluded, . . . it is
    ordinarily ‘substantially more difficult’ to establish.” Lujan,
    
    504 U.S. at 562
     (citations omitted). This time, in my view, it is
    not only difficult, it is impossible. The generalized public good
    that petitioners seek is the thing of legislatures and presidents,
    not of courts. As we stated in another environmental case, to
    ascertain standing courts must ask the question, did the
    “underlying governmental act [or inaction] demonstrably
    increase[] some specific risk of environmental harm to the
    interest of the plaintiff”? Florida Audubon Soc’y, 94 F.3d at 667
    (emphasis in original). Here, as in Florida Audubon, the alleged
    harm is not particularized, not specific, and in my view, not
    justiciable.
    Therefore, I would reject and dismiss all the petitions before
    us. This is not to say that petitioners’ complaints are wrong.
    This is not to say they are without redress. This is to say only
    that the question is not justiciable in its present form with its
    present champions in the present forum. A case such as this, in
    4
    which plaintiffs lack particularized injury is particularly
    recommended to the Executive Branch and the Congress.
    Because plaintiffs’ claimed injury is common to all members of
    the public, the decision whether or not to regulate is a policy call
    requiring a weighing of costs against the likelihood of success,
    best made by the democratic branches taking into account the
    interests of the public at large. There are two other branches of
    government. It is to those other branches that the petitioners
    should repair.
    II. Concurrence in the Judgment
    My conclusion leaves a slight problem. No problem exists
    as to the petitions for review of nonfinal action which Judge
    Randolph’s opinion orders dismissed. I would dismiss those as
    well, on either his ground or mine. The problem vexes only as
    to petitions for review in Nos. 03-1361, 03-1362, 03-1363, and
    03-1364, which Judge Randolph would deny and Judge Tatel
    would grant. I would dismiss those as well, as I would hold that
    we have no jurisdiction to either deny or grant them. How then
    are we to reach a judgment?
    The Supreme Court has suggested a way, or at least Justices
    of the Supreme Court have. Most recently, in Hamdi v.
    Rumsfeld, 
    124 S. Ct. 2633
     (2004), Justice Souter, joined by
    Justice Ginsburg, differed from the plurality in a fragmented
    opinion adjudicating the due process rights of alleged enemy
    combatants held at Guantanamo Bay by the United States
    military. Justices Souter and Ginsburg would have vacated the
    judgment of the Court of Appeals and remanded for proceedings
    consistent with their view that the government had failed to
    justify holding the petitioner. However, because that view did
    not command a majority of the court, and because of “the need
    to give practical effect to the conclusion of [a majority] of the
    court rejecting the government’s position,” Justice Souter
    5
    (joined by Justice Ginsburg) joined with the plurality “in
    ordering a remand on terms closest to those I would impose.”
    
    124 S. Ct. at 2660
     (Souter, J., concurring). I will take a similar
    course here.
    The majority today holds that we have jurisdiction to render
    judgment on four of the petitions before us. Although I
    disagree, I will accept the decision of the majority as dictating
    the law of this case. Having so accepted the law of the case, I
    will then join Judge Randolph in the issuance of a judgment
    closest to that which I myself would issue.             With that
    explanation, I join in the decision to order denying the four
    petitions from final action of the Environmental Protection
    Agency.
    TATEL, Circuit Judge, dissenting in Nos. 03-1361, 03-1362,
    03-1363, and 03-1364: Petitioners claim that motor vehicle
    emissions of greenhouse gases contribute to global warming and
    that global warming in turn is causing a host of serious
    problems, likely including increased flash flood potential in the
    Appalachians, degraded water quality and reduced water supply
    in the Great Lakes, sea-ice melting and permafrost thawing in
    Alaska, reduced summer snow-pack runoff in the Rockies,
    extreme water resource fluctuations in Hawaii, and rising sea
    levels combined with higher storm surges along the coasts of
    Puerto Rico, the Virgin Islands, and some eastern states. See
    Pet’rs Br. at 8-10 (summarizing U.S. Dep’t of State, U.S.
    Climate Action Report 2002, at 110). Concerned about such
    problems, petitioners asked EPA to regulate these emissions
    under Clean Air Act section 202(a)(1), which provides: “The
    Administrator shall by regulation prescribe . . . standards
    applicable to the emission of any air pollutant from . . . new
    motor vehicles . . . which in his judgment cause, or contribute to,
    air pollution which may reasonably be anticipated to endanger
    public health or welfare.” 
    42 U.S.C. § 7521
    (a)(1). EPA denied
    the petition on two grounds—that it lacked statutory authority to
    regulate such emissions and that even given such authority it
    would not exercise it—and petitioners sought review in this
    court.
    My colleagues agree that the petitions for review should not
    be granted, but they do so for quite different reasons. Judge
    Sentelle thinks that petitioners lack standing and would dismiss
    the petitions for that reason. Judge Randolph does not resolve
    whether petitioners have standing and would deny the petitions
    based on one of EPA’s two given reasons.
    I have yet a different view. Unlike Judge Sentelle, I think
    at least one petitioner has standing, as I explain in Part II.
    Unlike Judge Randolph, I think EPA’s order cannot be sustained
    on the merits. EPA’s first given reason—that it lacks statutory
    2
    authority to regulate emissions based on their contribution to
    welfare-endangering climate change, 
    68 Fed. Reg. 52,922
    ,
    52,925-29 (Sept. 8, 2003)—fails, as I explain in Part III, because
    the statute clearly gives EPA authority to regulate “any air
    pollutant” that may endanger welfare, 
    42 U.S.C. § 7521
    (a)(1),
    with “air pollutant” defined elsewhere in the statute as
    “including any physical, chemical, biological, radioactive . . .
    substance or matter which is emitted into or otherwise enters the
    ambient air,” 
    id.
     § 7602(g). EPA’s second given reason—the
    one accepted by Judge Randolph—is that even if it has statutory
    authority, it nonetheless “believes” that “it is inappropriate to
    regulate [greenhouse gas] emissions from motor vehicles” due
    to various policy reasons. As I explain in Part IV, however,
    none of these policy reasons relates to the statutory
    standard—“cause, or contribute to, air pollution which may
    reasonably be anticipated to endanger public health or welfare,”
    id. § 7521(a)(1)—and the Clean Air Act gives the Administrator
    no discretion to withhold regulation for such reasons.
    In short, EPA has failed to offer a lawful explanation for its
    decision. I would accordingly grant the petitions for review and
    send the matter back to EPA either to make an endangerment
    finding or to come up with a reasoned basis for refusing to do so
    in light of the statutory standard.
    I.
    “Greenhouse gases are accumulating in Earth’s atmosphere
    as a result of human activities, causing surface air temperatures
    and subsurface ocean temperatures to rise.” So begins page one
    of the National Research Council’s 2001 report, Climate Change
    Science: An Analysis of Some of the Key Questions (“NRC
    Report”), the scientific document EPA “rel[ied]” on in denying
    the petition for rulemaking, see 68 Fed. Reg. at 52,930.
    As the NRC Report explains, greenhouse gases (GHGs) trap
    heat radiated from earth, and their atmospheric concentrations
    3
    are increasing “as a result of human activities.” NRC Rep. at 1,
    9. For example, “[h]uman activities . . . responsible for the
    increase” in atmospheric concentrations of carbon dioxide
    (CO2)—the chief GHG—include “[t]he primary source, fossil
    fuel burning,” as well as “[t]ropical deforestation.” Id. at 2; see
    also id. at 10, 12. The resulting increases are striking. In the
    400,000 years prior to the Industrial Revolution, atmospheric
    CO2 concentrations “typically ranged between 190” parts per
    million by volume (ppmv) “during the ice ages to near 280
    ppmv during the warmer ‘interglacial’ periods.” Id. at 11. By
    1958, atmospheric concentrations were 315 ppmv (12.5% above
    the pre-Industrial-Revolution high of 280 ppmv), and by 2000
    they had risen to 370 ppmv (17% above the 1958 level). Id. at
    10. Similarly, prior to the Industrial Revolution, atmospheric
    concentrations of methane (CH4), another GHG, ranged from .3
    ppmv to .7 ppmv; now, “current values are around 1.77 ppmv.”
    Id. at 11. Atmospheric concentrations of other GHGs like
    nitrous oxide (N2O) have also risen. Id. at 2. Notably, GHGs
    not only disperse throughout the lower atmosphere, but also
    linger there at length: “Reductions in the atmospheric
    concentrations of these gases following possible lowered
    emissions rates in the future will stretch out over decades for
    methane, and centuries and longer for carbon dioxide and
    nitrous oxide.” Id. at 10.
    Increased GHG atmospheric concentrations are causing
    “climate forcings”—“imposed perturbation[s] of Earth’s energy
    balance” measured in terms of units of watts per square meter
    (W/m2). Id. at 6. Drawing from another report—an
    Intergovernmental Panel on Climate Change (IPCC) report with
    which the NRC “generally agrees,” id. at 1—the NRC Report
    quantifies these climate forcings. CO2, “probably the most
    important climate forcing agent today,” has “caus[ed] an
    increased forcing of about 1.4 W/m2” between 1750 and 2000.
    Id. at 12, 13. More lies ahead:
    4
    CO2 climate forcing is likely to become more dominant in
    the future as fossil fuel use continues. If fossil fuels
    continue to be used at the current rate, the added CO2
    forcing in 50 years will be about 1 W/m2. If fossil fuel use
    increases by 1-1.5% per year for 50 years, the added CO2
    forcing instead will be about 2 W/m2.
    Id. at 12-13. Thus, by 2050, the total CO2 forcing since 1750
    could be from 2.4-3.4 W/m2. The other GHGs “together cause
    a climate forcing approximately equal to that of CO2,” or more
    if one includes certain indirect effects of increased CH4
    emissions. Id. at 13. While atmospheric GHG increases are not
    the only causes of climate forcings—for example, changes in
    solar irradiance and in concentrations of tropospheric ozone also
    appear to have caused climate forcings, and atmospheric
    concentration changes in aerosols like sulphates appear to have
    caused negative (cooling) climate forcings—all other forcings
    are less certain and appear less substantial than those caused by
    GHGs. See id.
    The extent to which these forcings affect average global
    temperatures depends on the climate’s sensitivity, a condition
    that is not precisely known. Id. at 7. “Well-documented climate
    changes . . . imply that the climate sensitivity is near . . . 3ºC”
    (5.4ºF) for a 4 W/m2 forcing—a number a bit above the total
    CO2 forcing predicted by 2050—“but with a range from 1.5ºC
    to 4.5ºC (2.7 to 8.1ºF).” Id.
    Turning to the practical effects of GHG climate forcings,
    the NRC Report observes that a “diverse array of evidence
    points to a warming of global surface temperatures.” Id. at 16.
    Though the “rate of warming has not been uniform,”
    measurements “indicate that global mean surface air temperature
    warmed by about .4-.8ºC (.7-1.5ºF) during the 20th century.” Id.
    The report notes that “[t]he Northern Hemisphere as a whole
    experienced a slight cooling from 1946-75,”—a statement Judge
    Randolph erroneously reads for the proposition that “global
    5
    temperatures decreased between 1946 and 1975,” op. of
    Randolph, J., at 12 (emphasis added)—possibly due to the
    widespread burning of high sulfur coal and resultant sulfate
    emissions or to changes in ocean circulation in the Atlantic.
    NRC Rep. at 16. The report also observes that, as the IPCC
    report points out, the “warming of the Northern Hemisphere
    during the 20th century is likely to have been the largest of any
    century in the past thousand years.” Id.
    In evaluating the relationship between GHG atmospheric
    increases and twentieth-century temperature increases, the NRC
    Report states that due to the
    large and still uncertain level of natural variability inherent
    in the climate record and the uncertainties in the time
    histories of various forcing agents (and particularly
    aerosols), a causal linkage between the buildup of
    greenhouse gases in the atmosphere and the observed
    climate changes during the 20th century cannot be
    unequivocally established.
    Id. at 17.       Although Judge Randolph seizes on this
    uncertainty—and portrays it as applying to global warming
    generally rather than to twentieth-century warming, see op. of
    Randolph, J., at 11—read in context, it appears little more than
    an application of the principle that, as the NRC Report later puts
    it, “[c]onfidence limits and probabilistic information, with their
    basis, should always be considered as an integral part of the
    information that climate scientists provide to policy and decision
    makers,” NRC Rep. at 22. Indeed, the NRC Report goes on to
    state that the “fact that the magnitude of the observed warming
    is large compared to natural variability as simulated in climate
    models is suggestive of such a linkage” between GHG
    atmospheric concentration increases and twentieth-century
    temperature increases, though not “proof” of it. Id. at 17.
    The NRC Report further suggests that uncertainties about
    6
    future warming relate chiefly to its scope.
    Climate change simulations for the period of 1990 to 2100
    based on IPCC emissions scenarios yield a globally-
    averaged surface temperature increase by the end of the
    century of 1.4 to 5.8ºC (2.5 to 10.4ºF) relative to 1990. The
    wide range of uncertainty in these estimates reflects both
    the different assumptions about future concentrations of
    greenhouse gases and aerosols in the various scenarios
    considered by the IPCC and the differing climate
    sensitivities of the various climate models used in the
    simulations. The range of climate sensitivities implied by
    these predictions is generally consistent with previously
    reported values.
    Id. at 3. These numbers, of course, are averages: the “predicted
    warming is higher over higher latitudes than low latitudes,
    especially during winter and spring, and larger over land than
    over sea.” Id.
    With this warming will come secondary effects. Predicted
    impacts in the United States include increased likelihood of
    drought, greater heat stress in urban areas, rising sea levels, and
    disruption to many U.S. ecosystems. Id. at 19-20. The
    likelihood and scope of these impacts vary depending on the
    magnitude of future temperature increases. See id.; see also id.
    at 4. Because the “predicted temperature increase is sensitive to
    assumptions concerning future concentrations of greenhouse
    gases and aerosols,” which in turn depend on future emissions,
    “national policy decisions made now and in the longer-term
    future will influence the extent of any damage suffered by
    vulnerable human populations and ecosystems later in this
    century.” Id. at 1.
    7
    II.
    EPA claims petitioners lack standing to bring this case. To
    reach the merits, however, we need determine only that one
    petitioner has standing. See, e.g., Nuclear Energy Inst., Inc. v.
    EPA, 
    373 F.3d 1251
    , 1266 (D.C. Cir. 2004). In my view,
    declarations submitted by petitioners clearly establish that the
    Commonwealth of Massachusetts has satisfied each element of
    Article III standing—injury, causation, and redressability, see,
    e.g., Lujan v. Defenders of Wildlife, 
    504 U.S. 555
    , 560-61
    (1992).
    Among other things, Massachusetts claims injury—the
    “substantial probability that local conditions will be adversely
    affected,” Sierra Club v. EPA, 
    292 F.3d 895
    , 898 (D.C. Cir.
    2002) (internal quotation marks omitted)—resulting from rising
    sea levels. The declaration of Paul Kirshen, a professor at Tufts
    University’s Civil and Environmental Engineering Department,
    details how projected rises in sea levels in the metropolitan
    Boston area would lead both to permanent loss of coastal land
    and to “more frequent and severe storm surge flooding events
    along the coast.” Kirshen Decl. ¶¶ 7-8; see also Jacqz Decl. ¶¶
    8-11. “[I]f sea level rises .3 meters (11.8 inches)—which is near
    the lower end of the likely range—that would mean the future
    10-year flood surge elevation would be at the level of the current
    100-year flood elevation and the future 100-year flood surge
    elevation would be at that of the current 500-year flood
    elevation.” Kirshen Decl. ¶ 10. As other declarations make
    clear, such changes would lead to serious loss of and damage to
    Massachusetts’s coastal property. See Hoogeboom Decl. ¶¶ 6-7;
    Jacqz Decl. ¶ 11.
    Given these declarations, I disagree that no petitioner
    suffers “harm particularized to” itself. See op. of Sentelle, J., at
    2.    The Commonwealth of Massachusetts claims an
    injury—namely, loss of land within its sovereign
    boundaries—that “affects [it] in a personal and individual way,”
    8
    Lujan, 
    504 U.S. at
    560 n.1. This loss (along with increased
    flood damage to the Massachusetts coast) undeniably harms the
    Commonwealth in a way that it harms no other state. Other
    states may face their own particular problems stemming from
    the same global warming—Maine may suffer from loss of
    Maine coastal land and New Mexico may suffer from reduced
    water supply—but these problems are different from the injuries
    Massachusetts faces. Massachusetts’s harm is thus a far cry
    from the kind of generalized harm that the Supreme Court has
    found inadequate to support Article III standing, i.e., “harm to
    [its] and every citizen’s interest in proper application of the
    Constitution and laws,” or put another way “relief that no more
    directly and tangibly benefits [it] than it does the public at
    large,” 
    id. at 573-74
    .
    As to causation, the declaration of Michael MacCracken,
    the senior scientist on global change at the Office of the U.S.
    Global Change Research Program from 1993-2002, states that
    global warming is causing sea level increases like those in
    Massachusetts. “[T]he warming of the oceans and the increased
    melting of many mountain glaciers around the world . . . were
    the major contributions to the rise in global sea level by 10-20
    cm (4 to 8 inches) observed over the past century” and the
    “environmental impacts of projected global warming will
    include . . . an increase in sea level at an average rate of about .5
    to 3.5 inches per decade, reaching 4-35 inches by the end of the
    century (with the most likely value being, in my expert opinion,
    near or above the middle of this range).” MacCracken Decl. ¶
    5(c)-(d); see also id. ¶ 23. MacCracken further states that global
    warming is chiefly triggered by human-caused GHG emissions,
    see id. ¶¶ 5(a)-(b), 12-19, with “the U.S. transportation sector
    (mainly automobiles) . . . responsible for about 7% of global
    fossil fuel emissions,” id. ¶ 31.
    Finally, as to redressability, MacCracken emphasizes that
    “[a]chievable reductions in emissions of CO2 and other [GHGs]
    9
    from U.S. motor vehicles would . . . delay and moderate many
    of the adverse impacts of global warming.” Id. ¶5(e).
    Elaborating, he states that “[g]iven the large emissions of CO2
    and other [GHGs] from motor vehicles in the United States and
    the lead time needed to economically introduce changes into the
    motor vehicle fleet, emission reductions must be initiated in the
    near future in order to significantly reduce and delay the impacts
    of global warming.” Id. ¶ 31. Because the extent of damage to
    the Massachusetts coastline depends on the magnitude of the
    rise in sea level, a reduction in this projected adverse
    consequence of global warming would partially redress
    Massachusetts’s injury. See Tozzi v. U.S. Dep’t of Health &
    Human Servs., 
    271 F.3d 301
    , 310 (D.C. Cir. 2001) (holding that
    a petitioner need only demonstrate it would receive “at least
    some” relief to establish redressability). Nowhere disputing this
    proposition, EPA instead claims that MacCracken’s conclusion
    depends upon the assumption that other countries will follow the
    U.S. lead and regulate motor vehicle GHG emissions. Even
    were this reading of the declaration correct—a dubious premise
    given MacCracken’s unqualified language focusing on U.S.
    emissions reduction—the uncontested declaration of Michael
    Walsh, a consultant on motor vehicle pollution technology and
    at one point director of EPA’s motor vehicle pollution control
    efforts, provides a basis for concluding that other countries
    would come to mandate technology developed in response to
    U.S. regulation. Describing how in the past other countries have
    come to require such technology, Walsh concludes that “[o]n the
    basis of my experience with the control of other pollutants . . .
    I have no doubt that establishing emissions standards for
    pollutants that contribute to global warming would lead to
    investment in developing improved technologies to reduce those
    emissions from motor vehicles, and that successful technologies
    would gradually be mandated by other countries around the
    world.” Walsh Decl. ¶¶ 7-8, 10.
    Judge Randolph, accepting that the declarations “do
    10
    ‘support each element’ of standing,” nonetheless questions
    whether this is enough. See op. of Randolph, J., at 8 (quoting
    Sierra Club, 
    292 F.3d at 899
    ). Specifically, he believes we
    confront a question left open in our Sierra Club decision. In that
    case, we held that “[t]he petitioner’s burden of production in the
    court of appeals is . . . the same as that of a plaintiff moving for
    summary judgment in the district court: it must support each
    element of its claim to standing ‘by affidavit or other
    evidence.’” 
    292 F.3d at 899
     (quoting Lujan, 
    504 U.S. at 561
    ).
    But we never explicitly addressed what happens if the agency
    submits evidence that contradicts that of petitioners. Do we
    resolve factual disputes in petitioners’ favor, return the case to
    the agency for fact-finding, send the matter to a special master,
    or pursue some other course of action?
    The issue is fascinating, but we need not confront it. Given
    that the burdens of production here are comparable to those at
    summary judgment, see 
    292 F.3d at 899
    , if EPA wants to
    challenge the facts petitioners have set forth in their affidavits,
    it has an obligation to respond to the petitioners by “citing any
    record evidence relevant to . . . standing and, if necessary,
    appending to its filing additional affidavits or other evidence,”
    see 
    id. at 900-01
    . EPA makes no such challenge.
    Indeed, if anything, the order under review appears to
    support petitioners’ standing. While, drawing on the NRC
    Report, EPA observes that “there continue to be important
    uncertainties in our understanding of the factors that may affect
    future climate change,” 68 Fed. Reg. at 52,930, EPA never
    denies the “substantial probability,” see Sierra Club, 
    292 F.3d at 898
    , that injurious global warming is occurring. Quite to the
    contrary, EPA “agree[s] with the President that ‘we must
    address the issue of global climate change.’” 68 Fed. Reg. at
    52,929 (quoting presidential statement of Feb. 14, 2002). As to
    causation and redressability, the petition denial emphasizes that
    “EPA is also working to encourage voluntary GHG emission
    11
    reductions from the transportation sector” and that “the
    Administration’s global climate change policy includes
    promoting the development of fuel-efficient motor vehicles and
    trucks, researching options for producing cleaner fuels, and
    implementing programs to improve energy efficiency.” Id. at
    52,932; see also NRC Rep. at 1 (noting that “national policy
    decisions made now . . . will influence the extent of any
    damage” caused by global warming). EPA would presumably
    not bother with such efforts if it thought emissions reductions
    would have no discernable impact on future global warming.
    Because EPA nowhere challenges petitioners’ declarations,
    I see no reason to consider what we would do if it had done so.
    Thus, unlike Judge Randolph, I think it unnecessary to address
    whether we can carve out exceptions to the Supreme Court’s
    seemingly unqualified holding that “a merits question cannot be
    given priority over an Article III question,” Steel Co. v. Citizens
    for a Better Env’t, 
    523 U.S. 83
    , 97 n.2 (1998). The
    Commonwealth of Massachusetts has adequately demonstrated
    its standing, and our jurisdiction is plain.
    III.
    As to the merits, the threshold question is this: does the
    Clean Air Act authorize EPA to regulate emissions based on
    their effects on global climate? Taking a constricted view, EPA
    insists it has no authority to regulate GHG emissions even if
    they contribute to substantial and harmful global warming. By
    contrast, petitioners claim that Congress has plainly given EPA
    the authority it says it lacks.
    “If a court, employing traditional tools of statutory
    construction, ascertains that Congress had an intention on the
    precise question at issue, that intention is the law and must be
    given effect.” Chevron U.S.A., Inc. v. Natural Res. Def.
    Council, Inc., 
    467 U.S. 837
    , 843 n.9 (1984). The inquiry
    “begin[s], as always, with the plain language of the statute in
    12
    question.” Consumer Elecs. Ass’n v. FCC, 
    347 F.3d 291
    , 297
    (D.C. Cir. 2003) (quoting Citizens Coal Council v. Norton, 
    330 F.3d 478
    , 482 (D.C. Cir. 2003)). CAA section 202(a)(1), added
    by Congress in 1965 and amended in 1970 and 1977, provides,
    The Administrator shall by regulation prescribe . . .
    standards applicable to the emission of any air pollutant
    from any class or classes of new motor vehicles or new
    motor vehicle engines which in his judgment cause, or
    contribute to, air pollution which may reasonably be
    anticipated to endanger public health or welfare.
    
    42 U.S.C. § 7521
    (a)(1). This language plainly authorizes
    regulation of (1) any air pollutants emitted from motor vehicles
    that (2) in the Administrator’s judgment cause, or contribute to,
    air pollution which may reasonably be anticipated to endanger
    public health or welfare. EPA’s claimed lack of authority
    relates to the first of these two elements. According to EPA,
    GHGs like CO2, CH4, N2O, and hydrofluorocarbons (HFCs) “are
    not air pollutants.” 68 Fed. Reg. at 52,928.
    Congress, however, left EPA little discretion in determining
    what are “air pollutants.” Added in 1970 and amended in 1977,
    CAA section 302(g) defines the term as follows:
    The term ‘air pollutant’ means any air pollution agent or
    combination of such agents, including any physical,
    chemical, biological, radioactive . . . substance or matter
    which is emitted into or otherwise enters the ambient air.
    
    42 U.S.C. § 7602
    (g). This exceedingly broad language plainly
    covers GHGs emitted from motor vehicles: they are “physical
    [and] chemical . . . substance[s] or matter . . . emitted into . . .
    the ambient air.” Indeed, in one CAA provision, added in 1990,
    Congress explicitly included CO2 in a partial list of “air
    pollutants.” Section 103(g) instructs the Administrator to
    research “nonregulatory strategies and technologies for
    preventing or reducing multiple air pollutants, including sulfur
    13
    oxides, nitrogen oxides, heavy metals, PM-10 (particulate
    matter), carbon monoxide, and carbon dioxide.” 
    Id.
     § 7403(g)
    (emphasis added). Faced with such language, a court—as well
    as an agency—would normally end the analysis here and
    conclude that GHGs are “air pollutants,” since “[w]e ‘must
    presume that a legislature says in a statute what it means and
    means in a statute what it says . . . . When the words of a statute
    are unambiguous . . . this first canon is also the last: judicial
    inquiry is complete.’” Teva Pharm. Indus. Ltd. v. Crawford,
    
    410 F.3d 51
    , 53 (D.C. Cir. 2005) (quoting Conn. Nat’l Bank v.
    Germain, 
    503 U.S. 249
    , 253-54 (1992)) (omissions in original).
    Unswayed by what it calls “narrow semantic analyses,”
    Resp’t Br. at 55—but what courts typically call Chevron step
    one—EPA claims that a “more holistic analysis . . . [of] the text,
    structure, and history of the CAA as a whole, as well as the
    context provided by other legislation that is specific to climate
    change,” justifies its conclusion that it cannot regulate GHGs
    like CO2 for their effects on climate change, id. at 25-26. To
    disregard the Act’s plain text in this way, EPA needs an
    “extraordinarily convincing justification.” Appalachian Power
    Co. v. EPA, 
    249 F.3d 1032
    , 1041 (D.C. Cir. 2001). “For the
    EPA to avoid a literal interpretation at Chevron step one, it must
    show either that, as a matter of historical fact, Congress did not
    mean what it appears to have said, or that, as a matter of logic
    and statutory structure, it almost surely could not have meant it.”
    Engine Mfrs. Ass’n v. EPA, 
    88 F.3d 1075
    , 1089 (D.C. Cir.
    1996).
    EPA offers four reasons for abandoning the Act’s text.
    First, it suggests that since the 1965, 1970, and 1977 Congresses
    were not specifically concerned with global warming, the Act
    cannot apply to GHGs. Second, it claims that for both practical
    and policy reasons, global pollution should be tackled through
    specific statutory provisions rather than general ones. Third,
    relying on FDA v. Brown & Williamson Tobacco Corp., 529
    
    14 U.S. 120
     (2000), it argues that Congress’s passage of legislation
    calling for study of climate change, along with Congress’s
    failure to pass any provisions tailored solely to regulating
    GHGs, demonstrates that the CAA cannot apply to GHGs.
    Finally, EPA suggests that Congress couldn’t have intended the
    definition of “air pollutant” to cover CO2, since EPA regulation
    of CO2 emissions from automobiles would overlap with
    Department of Transportation (DOT) authority over fuel
    economy standards under a different act. None of these reasons
    provides a convincing justification—let alone an
    “extraordinarily convincing” one—for EPA’s counter-textual
    position.
    EPA first suggests that because the 1965, 1970, and 1977
    Congresses showed little concern about the specific problem of
    global warming, reading the CAA’s language to cover such
    problems would be like finding “an elephant in a mousehole.”
    Tr. of Oral Arg. at 32; see also Resp’t Br. at 23 (quoting
    Whitman v. Am. Trucking Ass’ns, 
    521 U.S. 457
    , 468 (2002)).
    EPA is correct that those Congresses spilled little ink on the
    issue of global warming: while the legislative history contains
    a few stray references to human-forced climate change, see, e.g.,
    111 Cong. Rec. 25,061 (Sept. 24, 1965) (statement of Rep.
    Helstoski); 116 Cong. Rec. 32,914 (Sept. 21, 1970) (report
    introduced in the record by Sen. Boggs), in those years the
    scientific understanding of the issue was nascent at best, see,
    e.g., Environmental Quality: The First Annual Report of the
    Council on Environmental Quality 93 (1970) (noting that “[m]an
    may be changing his weather” but expressing uncertainty as to
    whether global warming or cooling was occurring). But EPA
    errs in suggesting that because Congress may not have precisely
    foreseen global warming, the Act provides no authorization for
    GHG regulation. Hardly a mousehole, the definition of “air
    pollutants”—“including any physical, chemical, biological,
    radioactive . . . substance or matter which is emitted into or
    otherwise enters the ambient air”—enables the Act to apply to
    15
    new air pollution problems as well as existing ones. “[T]he fact
    that a statute can be applied in situations not expressly
    anticipated by Congress,” the Supreme Court has explained,
    “does not demonstrate ambiguity. It demonstrates breadth.”
    PGA Tour, Inc. v. Martin, 
    532 U.S. 661
    , 689 (2001) (quoting
    Pa. Dep’t of Corrections v. Yeskey, 
    524 U.S. 206
    , 212 (1998)).
    Indeed, Congress expressly instructed EPA to be on the lookout
    for climate-related problems in evaluating risks to “welfare.”
    Section 302(h), added in 1970, explains that “[a]ll language
    referring to effects on welfare includes, but is not limited to,
    effects on soils, water, crops, vegetation, manmade materials,
    animals, wildlife, weather, visibility, and climate.” 
    42 U.S.C. § 7602
    (h) (emphasis added).
    EPA’s second reason for its interpretation—that for
    practical and policy reasons global warming should be dealt
    with through specifically tailored statutes—likewise fails to
    trump Congress’s plain language. It may well be that a statute
    aimed solely at global warming would deal with the problem
    more effectively than one aimed generally at air pollution. But
    an agency may not “avoid the Congressional intent clearly
    expressed in the [statutory] text simply by asserting that its
    preferred approach would be better policy.” Engine Mfrs. Ass’n,
    
    88 F.3d at 1089
    . Perhaps recognizing this point, EPA attempts
    to link its policy arguments to the statute by claiming that
    because the 1977 and 1990 Congresses enacted provisions
    specific to another global pollution problem—depletion of
    stratospheric ozone—we must infer that the Act’s general
    provisions do not cover such global problems. Once again, EPA
    makes much of very little. While the 1977 Congress did add
    provisions aimed specifically at ozone depletion, it also made
    clear that “[n]othing in this [ozone-specific] part shall be
    construed to alter or affect the authority of the Administrator
    under . . . any other provision of this Act.” Pub. L. No. 95-95,
    § 158, 
    91 Stat. 685
    , 730 (1977); see also H.R. Rep. No. 95-294,
    at 102 (1977) (expressing the House Committee’s view that
    16
    EPA could already regulate emissions to protect stratospheric
    ozone under an existing general provision of the CAA).
    Similarly, I see nothing in the 1990 Congress’s enactment of
    other provisions specific to stratospheric ozone protection, see
    
    42 U.S.C. §§ 7671
     to 7671q, indicating it thought EPA lacked
    authority under general provisions like section 202 to regulate
    emissions contributing to global pollution. This is particularly
    true since that Congress also enacted provisions specific to
    certain regional pollutants, see, e.g., 
    id.
     §§ 7651 to 7651o (acid
    rain control), which, pursuant to general CAA provisions, EPA
    already had authority to regulate.
    EPA also attempts an unworkability argument. Its
    argument goes like this: another part of the CAA provides that
    the Administrator shall maintain a list of air pollutants that,
    among other things, “in [the Administrator’s] judgment, cause
    or contribute to air pollution which may reasonably be
    anticipated to endanger public health or welfare.” Id. §
    7408(a)(1)(A). Once pollutants go on this list, the Administrator
    must set national ambient air quality standards (NAAQS) for
    them, i.e., ambient air concentration levels that, in the
    Administrator’s judgment, “are requisite to protect the public
    health” and in some areas are “requisite to protect the public
    welfare.” Id. § 7409(b); see also id. §§ 7407, 7410(a)(1). States
    must submit plans explaining how they will achieve these
    NAAQS. Id. § 7410. According to EPA, these provisions
    would be unworkable if applied to CO2: because CO2 disperses
    relatively evenly throughout the lower atmosphere, states would
    have only minimal control over their atmospheric CO2
    concentrations and thus over whether they meet the CO2
    NAAQS. EPA then concludes that because CO2 regulation
    would be unworkable in the NAAQS context, no general CAA
    provisions, including section 202(a)(1), authorize it to regulate
    any GHGs.
    This unwieldy argument fails. Even assuming that states’
    17
    limited ability to meet CO2 NAAQS renders these provisions
    unworkable as to CO2, but see id. § 7509a(a) (providing a safe
    harbor for states that fail to meet NAAQS due to emissions
    emanating from outside the country), the absurd-results canon
    would justify at most an exception limited to the particular
    unworkable provision, i.e., the NAAQS provision. See Mova
    Pharm. Corp. v. Shalala, 
    140 F.3d 1060
    , 1068 (D.C. Cir. 1998).
    As EPA acknowledges, regulating CO2 emissions from
    automobiles is perfectly feasible. See 68 Fed. Reg. at 52,929
    (noting that “improving fuel economy” is a “practical way of
    reducing tailpipe CO2 emissions” and that other technologies for
    reducing emissions may develop in the future).
    In support of its third justification for abandoning the plain
    text of sections 202(a)(1) and 302(g), EPA relies on later
    congressional action (and inaction). Specifically, EPA points
    out (1) that all direct references to CO2 or global warming in the
    1990 CAA amendments appear in nonregulatory provisions; (2)
    that other congressional acts such as the 1978 National Climate
    Program Act, the 1987 Global Climate Protection Act, the 1990
    Global Change Research Act, and the 1992 Energy Policy Act,
    as well as several appropriations riders, touch specifically on the
    issue of global warming, typically by instructing agencies to
    study the issue; and (3) that Congress has considered and
    rejected many bills specifically tailored to GHG emissions
    regulation since at least 1990. One might well wonder what all
    this has to do with whether GHGs are “air pollutants” within the
    meaning of CAA section 302(g). But relying almost exclusively
    on Brown & Williamson, 
    529 U.S. 120
    , EPA claims that
    together these facts indicate that the CAA’s general provisions
    do not cover GHGs. EPA also asserts that, as in Brown &
    Williamson, the “extraordinary” political and economic
    significance of the regulation requested casts doubt on the
    agency’s authority to undertake it. See Resp’t Br. at 21-22.
    In Brown & Williamson, the Court considered whether the
    18
    FDA had authority to regulate tobacco products. Although the
    Food, Drug, and Cosmetic Act’s broad language suggested that
    it did, the Court, acknowledging that “a specific policy
    embodied in a later federal statute should control our
    construction of the [earlier] statute, even though it ha[s] not been
    expressly amended,” 
    529 U.S. at 143
     (quoting United States v.
    Estate of Romani, 
    523 U.S. 517
    , 530-31 (1998)) (alterations in
    original), concluded that the FDA lacked such authority. In
    reaching this conclusion, the Court relied on a direct,
    irreconcilable conflict between FDA jurisdiction over tobacco
    under the FDCA and later statutes expressly regulating tobacco.
    If the FDA had jurisdiction over tobacco products, it would have
    had to ban them entirely due to their health risks, yet the
    subsequent acts “reveal[ed Congress’s] intent that tobacco
    products remain on the market.” 
    529 U.S. at 139
    . Moreover, as
    the Court emphasized—at least eighteen times by my
    count—the FDA had repeatedly claimed to have “no authority
    under the FDCA to regulate tobacco products,” 
    id. at 157
    , and
    “Congress’s tobacco-specific statutes ha[d] effectively ratified
    the FDA’s long-held position,” 
    id. at 144
    . See generally 
    id. at 125-26, 130-31, 144-46, 151-57
    .
    EPA’s reliance on Brown & Williamson is misplaced. To
    begin with, I am unconvinced by EPA’s contention that its
    jurisdiction over GHG emissions would be as significant as
    FDA jurisdiction over tobacco. Acting under the CAA, EPA
    already extensively regulates the energy and transportation
    industries, whereas the FDA had no prior authority over the
    tobacco industry. Moreover, EPA jurisdiction would lead only
    to regulation of GHGs—with, in the case of section 202,
    regulation taking effect only after “such period as the
    Administrator finds necessary” for development of technology,
    “giving appropriate consideration to the cost of compliance,” 
    42 U.S.C. § 7521
    (a)(2). By contrast, FDA jurisdiction over tobacco
    would have triggered a total product ban. But even assuming
    the implications are equally significant, this is not an
    19
    “extraordinary” case where “common sense,” see Brown &
    Williamson, 
    529 U.S. at 133, 159
    , calls into question whether
    Congress has delegated EPA authority to regulate GHGs.
    Congress gave EPA broad authority to regulate all harmful
    pollutants, as section 202(a)(1)’s text makes clear. Congress did
    so intentionally, deeming it “not appropriate to exempt certain
    pollutants” from the Act’s “comprehensive protections.” See
    H.R. Rep. No. 95-294, at 42-43. And, as I explain below, no
    subsequent statutory indicia comparable to those relied on by the
    Court in Brown & Williamson justify a different conclusion.
    Perhaps most significantly, no conflict exists between
    EPA’s section 202(a)(1) authority to regulate GHGs and
    subsequent global warming legislation. Whereas an FDA ban
    on tobacco would have directly conflicted with congressional
    intent that tobacco remain on the market, EPA regulation of
    GHGs would be fully compatible with statutes proposing
    additional research and other nonregulatory approaches to
    climate change. Take the three 1990 CAA additions referencing
    carbon dioxide or global warming. Section 103(g) calls for
    “nonregulatory strategies and technologies” for reducing
    pollutants like sulpher oxides, carbon monoxide, and carbon
    dioxide. 
    42 U.S.C. § 7403
    (g). While the section also provides
    that “[n]othing in this subsection shall be construed to authorize
    the imposition on any person of air pollution control
    requirements,” 
    id.
     (emphasis added), it nowhere suggests that
    EPA lacks authority to regulate carbon dioxide—or, for that
    matter, sulpher oxides, carbon monoxide, and other
    pollutants—under different parts of the Act. Section 602(e) is
    similar. One sentence requires the Administrator to “publish the
    global warming potential” of certain listed substances, and the
    next sentence notes that “[t]he preceding sentence shall not be
    construed to be the basis of any additional regulation under this
    chapter.” 
    Id.
     § 7671a(e). Once again, nothing in this provision
    bars regulation under other parts of the Act. The third
    provision—an uncodified section—merely requires sources
    20
    subject to the Act’s Title V to “monitor carbon dioxide
    emissions,” and says nothing about regulation one way or the
    other. Pub. L. No. 101-549, § 821, 
    104 Stat. 2399
    , 2699 (1990).
    Other climate-related acts similarly demonstrating congressional
    intent that global climate issues receive study and attention are
    likewise perfectly compatible with GHG regulation. See
    generally National Climate Program Act of 1978, Pub. L. No.
    95-367, 
    92 Stat. 601
    ; Global Climate Protection Act of 1987,
    Pub. L. No. 100-204, §§ 1101-1106, 
    101 Stat. 1331
    , 1407-09;
    Global Change Research Act of 1990, Pub. L. No. 101-606, 
    104 Stat. 3096
    ; Energy Policy Act of 1992, Pub. L. No. 102-486, 
    106 Stat. 2776
    .
    Furthermore, and unlike subsequent tobacco legislation that
    “effectively ratified the FDA’s previous position,” Brown &
    Williamson, 
    529 U.S. at 156
    , this subsequent global-warming-
    related legislation passed without any assurance from EPA that
    the agency lacked authority to regulate GHGs. Quite to the
    contrary, at the time of the two appropriations riders relied on by
    EPA, see, e.g., Pub. L. No. 105-276, 
    112 Stat. 2461
    , 2496
    (1998) (barring use of funds for implementation of the Kyoto
    Protocol), EPA was taking the position that it possessed general
    authority to regulate GHG emissions under section 202(a)(1).
    See Memorandum, J. Cannon to C. Browner (April 10, 1998).
    Finally, the fact that later Congresses failed to pass bills
    specifically tailored to regulating global warming hardly
    provides a basis for inferring that earlier Congresses meant to
    exclude climate-endangering pollutants from the coverage of the
    CAA’s general provisions. Not only is “subsequent legislative
    history . . . a ‘hazardous basis for inferring the intent of an
    earlier’ Congress,” but it “is a particularly dangerous ground . .
    . when it concerns, as it does here . . . proposal[s] that do[] not
    become law.” Pension Benefit Guar. Corp. v. LTV Corp., 
    496 U.S. 633
    , 650 (1990) (citation omitted). Indeed, in interpreting
    the scope of the FDA’s authority, the Brown & Williamson
    Court itself expressly declined to rely on failed legislation. 529
    21
    U.S. at 155.
    EPA has one last argument, applicable to CO2 emissions
    alone, for claiming it lacks the authority the language of sections
    202(a)(1) and 302(g) expressly bestow upon it. According to
    EPA, the only practical way to regulate CO2 emissions from
    motor vehicles is to require increased fuel economy, since CO2
    is a byproduct of fuel combustion and “[n]o technology
    currently exists or is under development that can capture and
    destroy or reduce” CO2 “emissions from motor vehicle
    tailpipes.” 68 Fed. Reg. at 52,929. Such regulation, EPA
    reasons, would overlap substantially with DOT’s authority under
    the 1975 Energy Policy and Conservation Act (EPCA) to set
    average fuel economy standards for certain classes of motor
    vehicles. See Pub. L. No. 94-163, § 502, 
    89 Stat. 871
    , 902-07
    (1975). Though recognizing that no direct conflict would occur
    since both agencies would set minimum standards, EPA
    concludes that “any EPA effort to set CO2 tailpipe emissions
    under the CAA would either abrogate EPCA’s regime (if the
    standards were effectively more stringent than the applicable
    [DOT] standard) or be meaningless (if they were effectively less
    stringent).” 68 Fed. Reg. at 52,929.
    EPA may well be correct that setting standards for fuel
    economy (rather than for capturing tailpipe emissions)
    represents its only currently practical option for regulating CO2
    emissions. But cf. 
    42 U.S.C. § 7521
    (a)(2) (requiring section
    202(a)(1) regulation to take effect only “after such period as the
    Administrator finds necessary to permit the development and
    application of the requisite technology”). But given that the two
    regulatory regimes—one targeted at fuel conservation and the
    other at pollution prevention—are overlapping, not
    incompatible, there is no reason to assume that Congress
    exempted CO2 from the meaning of “air pollutant” within the
    CAA, particularly since section 103(g) explicitly calls CO2 an
    “air pollutant.” Where two “statutes are ‘capable of co-
    22
    existence,’ it becomes the duty of this court ‘to regard each as
    effective’—at least absent clear congressional intent to the
    contrary.” FTC v. Ken Roberts Co., 
    276 F.3d 583
    , 593 (D.C.
    Cir. 2001) (quoting Morton v. Mancari, 
    417 U.S. 535
    , 551
    (1974)). Moreover, Congress acknowledged, and indeed
    accepted, the possibility of regulatory overlap. Not only does
    the current EPCA recognize the relevance of “the effect of other
    motor vehicle standards of the Government on fuel economy,”
    
    49 U.S.C. § 32902
    (f); see also EPCA, Pub. L. No. 94-163, §
    502(e), 89 Stat. at 905, but in passing the 1977 CAA
    amendments Congress emphasized that EPA regulation under
    the CAA should go forward even where it overlaps with
    responsibilities given to other agencies under other acts, see
    H.R. Rep. No. 95-294, at 42-43 (explaining that Congress was
    amending section 302(g) to broaden the meaning of “air
    pollutants” and make clear that EPA has authority even over
    pollutants already regulated by another agency). As the 1977
    House Report explained, “the Clean Air Act is the
    comprehensive vehicle for protection of the Nation’s health
    from air pollution. In the committee’s view, it is not appropriate
    to exempt certain pollutants or certain sources from the
    comprehensive protections afforded by the Clean Air Act.” Id.
    In sum, GHGs plainly fall within the meaning of “air
    pollutant” in section 302(g) and therefore in section 202(a)(1).
    If “in [the Administrator’s] judgment” they “cause, or contribute
    to, air pollution which may reasonably be anticipated to
    endanger public health or welfare,” 
    42 U.S.C. § 7521
    (a)(1), then
    EPA has authority—indeed, the obligation—to regulate their
    emissions from motor vehicles.
    IV.
    EPA’s second reason for refusing to act—what EPA’s
    counsel termed “the fallback argument,” Tr. of Oral Arg. at
    41—is that even if GHGs are air pollutants, the agency gave
    23
    appropriate reasons and acted within its discretion in denying
    the petition for rulemaking. EPA stresses that our “arbitrary and
    capricious” standard of review is particularly deferential in
    reviewing an agency refusal to institute rulemaking. See Resp’t
    Br. at 11-12; cf. Motor Vehicle Mfrs. Ass’n v. EPA, 
    768 F.2d 385
    , 389 n.6 (D.C. Cir. 1985) (observing that the CAA judicial
    review provisions are identical to those in the APA). This is
    certainly true, but this court must nonetheless “consider whether
    the agency’s decisionmaking was reasoned,” and we will not
    permit the agency to make “plain errors of law.” See Am. Horse
    Protection Ass’n, Inc. v. Lyng, 
    812 F.2d 1
    , 5 (D.C. Cir. 1987)
    (internal quotation marks omitted). Indeed, “the agency has the
    heaviest of obligations to explain and expose every step of its
    reasoning,” so that we can “exercis[e] our responsibility to
    determine whether [its] decision is ‘arbitrary, capricious, an
    abuse of discretion, or otherwise not in accordance with law.’”
    See Am. Lung Ass’n v. EPA, 
    134 F.3d 388
    , 392-93 (D.C. Cir.
    1998) (quoting 
    42 U.S.C. § 7607
    (d)(9)) (reviewing EPA’s denial
    of a petition to revise a NAAQS).
    In my view, EPA has failed to satisfy this standard. Indeed,
    reading the relevant sections of EPA’s petition denial—one
    titled “No Mandatory Duty,” another “Different Policy
    Approach,” and a third “Administration Global Climate Change
    Policy,” see 68 Fed. Reg. at 52,929, 52,931—I find it difficult
    even to grasp the basis for EPA’s action. In its brief, EPA
    describes the petition denial as claiming that if the agency thinks
    regulating GHGs is a bad idea, the Administrator has discretion
    to withhold making a “judgment,” known as an “endangerment
    finding,” that GHG emissions “cause, or contribute to, air
    pollution which may reasonably be anticipated to endanger
    public health or welfare,” see 
    42 U.S.C. § 7521
    (a)(1). Yet the
    denial itself seems to rest more clearly (albeit still not clearly)
    on a belief that even if the Administrator makes an
    endangerment finding, that finding triggers no duty to set
    emission standards. In the end, though, it makes no difference
    24
    whether one or both rationales are genuinely given in the
    petition denial or whether they instead amount to post hoc
    rescue attempts. As I explain below, neither rationale is
    acceptable in light of section 202(a)(1)’s mandate.
    EPA’s Discretion to Make an Endangerment Finding
    In the petition denial, EPA states:
    [T]he CAA provision authorizing regulation of motor
    vehicle emissions does not impose a mandatory duty on the
    Administrator to exercise her judgment. Instead, section
    202(a)(1) provides the Administrator with discretionary
    authority to address emissions . . . . While section 202(a)(1)
    uses the word ‘shall,’ it does not require the Administrator
    to act by a specified deadline and it conditions authority to
    act on a discretionary exercise of the Administrator’s
    judgment regarding whether motor vehicle emissions cause
    or contribute to air pollution that may reasonably be
    anticipated to endanger public health or welfare.
    68 Fed. Reg. at 52,929. Expounding on this passage, EPA
    argues in its brief that “[t]he ICTA Petition Denial reflects
    EPA’s decision not to make any endangerment finding—either
    affirmative or negative—under section 202(a)(1).” Resp’t Br.
    at 62-63. In EPA’s view, “the Agency’s authority to make the
    threshold finding is discretionary” and petitioners err in
    suggesting that “if the statutory test for making the finding is
    met, EPA has no choice but to set standards.” Id. at 57 (internal
    quotation marks omitted).
    EPA’s brief also turns several policy concerns raised in
    other portions of its petition denial into rationales for holding off
    examining endangerment.           These concerns include the
    following: (1) “there continue to be important uncertainties in
    our understanding of the factors that may affect future climate
    change and how it should be addressed”; (2) petitioners
    25
    identified no technologies for reducing CH4, N2O, and HFC
    emissions, and technologies for reducing CO2 emissions either
    overlap with DOT’s authority or require further development;
    (3) regulation “would also result in an inefficient, piecemeal
    approach to addressing the climate change issue,” as the “U.S.
    motor vehicle fleet is one of many sources of GHG emissions
    both here and abroad”; (4) “[u]nilateral EPA regulation of motor
    vehicle GHG emissions could also weaken U.S. efforts to
    persuade key developing countries to reduce the GHG intensity
    of their economies”; and (5) “EPA disagrees with the regulatory
    approach urged by petitioners,” instead preferring “a number of
    nonregulatory approaches to reducing GHG emissions” in line
    with “the President’s global climate change policy” of
    “support[ing] vital global climate research and lay[ing] the
    groundwork for future action by investing in science,
    technology, and institutions.” See 68 Fed. Reg. at 52,929-33.
    EPA’s reasoning is simply wrong. In effect, EPA has
    transformed the limited discretion given to the Administrator
    under section 202—the discretion to determine whether or not
    an air pollutant causes or contributes to pollution which may
    reasonably be anticipated to endanger public health or
    welfare—into the discretion to withhold regulation because it
    thinks such regulation bad policy. But Congress did not give
    EPA this broader authority, and the agency may not usurp it.
    Section 202(a)(1)’s language—the “Administrator shall by
    regulation prescribe . . . standards applicable to the emission of
    any air pollutant from . . . new motor vehicles . . . which in his
    judgment cause, or contribute to, air pollution which may
    reasonably be anticipated to endanger public health or welfare,”
    
    42 U.S.C. § 7521
    (a)(1)—establishes the limits of EPA’s
    discretion. This section gives the Administrator the discretion
    only to “judg[e],” within the bounds of substantial evidence,
    whether pollutants “cause, or contribute to, air pollution which
    may reasonably be anticipated to endanger public health or
    26
    welfare.” If conflicting credible evidence exists, e.g., some
    evidence suggesting that GHGs may reasonably be anticipated
    to endanger welfare and other evidence suggesting the opposite,
    then the Administrator has discretion in weighing this evidence.
    If the facts are known but require no single conclusion as to
    whether a pollutant “may reasonably be anticipated to endanger
    public health or welfare”—such as in a case where there exists
    a small-to-moderate risk that a pollutant will cause a small-to-
    moderate amount of harm—then the Administrator has
    discretion in assessing whether these facts amount to
    endangerment. If the Administrator concludes based on
    substantial evidence that more research is needed before he can
    judge whether GHGs may reasonably be anticipated to endanger
    welfare, then he has discretion to hold off making a finding.
    But section 202(a)(1) plainly limits the Administrator’s
    discretion—his judgment—to determining whether the statutory
    standard for endangerment has been met. The Administrator has
    no discretion either to base that judgment on reasons unrelated
    to this standard or to withhold judgment for such reasons. In
    claiming otherwise, EPA not only ignores the statute’s language,
    but also fails to reckon with this circuit’s related precedent.
    Our en banc decision in Natural Resources Defense
    Council, Inc. v. EPA, 
    824 F.2d 1146
     (D.C. Cir. 1987), makes
    clear that the Administrator may only exercise “judgment” in
    evaluating whether the statutory standard has been met. There,
    considering a CAA provision authorizing the Administrator to
    set emission standards “at the level which in his judgment
    provides an ample margin of safety to protect the public health,”
    
    42 U.S.C. § 7412
    (b)(1)(B) (1982) (quoted in 
    824 F.2d at 1147
    ),
    we held that the Administrator had to base his determination on
    what level would “provide an ‘ample margin of safety.’” See
    
    824 F.2d at 1164-65
    . We struck down his proposed standards
    because he failed to ground them in the statute. See 
    id.
     at 1163-
    64 (“[T]he Administrator has made no finding with respect to
    27
    the effect of the chosen level of emissions on health. . . .
    Nowhere in the decision did the Administrator state that the
    1976 emission standards provide an ‘ample margin of safety.’”).
    Similarly, in Ethyl Corp. v. EPA, 
    541 F.2d 1
     (D.C. Cir.
    1976) (en banc), we considered whether EPA appropriately
    linked its policy analysis to the statutory standard. That case
    involved EPA’s decision to regulate leaded gasoline pursuant to
    CAA section 211(c)(1)(A), 42 U.S.C. § 1857f-6c(1)(A) (1976),
    currently codified as amended at 
    42 U.S.C. § 7545
    (c)(1)(A),
    which at that time provided that the Administrator “may”
    regulate fuel additives “if any emission products of such . . . fuel
    additive[s] will endanger the public health or welfare.”
    Determining that lead in gasoline presented “‘a significant risk
    of harm’ to the public health,” 
    541 F.2d at 7
    , EPA regulated it.
    Industry petitioners objected, claiming that the Administrator
    needed “proof of actual harm rather than of ‘a significant risk of
    harm.’” 
    Id. at 12
    . Siding with EPA, we held that the agency
    had discretion in determining what level of harm—or risk of
    harm—constitutes endangerment. 
    Id.
     We indicated that such
    determinations involve policy issues, but—as Judge Randolph
    neglects to mention, see op. of Randolph, J., at 13—these policy
    issues all related to whether the statutory standard had been met,
    i.e., to whether lead in gasoline endangered public health. See,
    e.g., 
    541 F.2d at 24
     (observing that “a determination of
    endangerment to public health is necessarily a question of policy
    that is to be based on an assessment of risks and that should not
    be bound by either the procedural or the substantive rigor proper
    for questions of fact”); 
    id. at 26
     (noting that “the statute accords
    the regulator flexibility to assess risks and make essentially
    legislative policy judgments”). Indeed, Ethyl makes quite clear
    that the Administrator’s policy-based discretion is limited to the
    terms of the statute. “All this is not to say that Congress left the
    Administrator free to set policy on his own terms. To the
    contrary, the policy guidelines are largely set, both in the
    statutory term ‘will endanger’ and in the relationship of that
    28
    term to other sections of the Clean Air Act. These prescriptions
    direct the Administrator’s actions.” 
    Id. at 29
    ; cf. Brown &
    Williamson, 
    529 U.S. at 140
     (noting that the FDA’s “judgment”
    about how best to achieve public health goals is “no substitute
    for the specific safety determinations required by the FDCA’s
    various operative provisions”).
    In yet another case, Her Majesty the Queen in Right of
    Ontario v. EPA, 
    912 F.2d 1525
     (D.C. Cir. 1990), we held that
    for EPA to decline to make an endangerment finding, it must
    have a statutorily based reason for doing so. The CAA section
    at issue provided that when the Administrator had “reason to
    believe that any air pollutant or pollutants emitted in the United
    States cause or contribute to air pollution which may reasonably
    be anticipated to endanger public health or welfare in a foreign
    country . . . , the Administrator shall give formal notice thereof
    to the Governor of the State in which such emissions originate.”
    
    Id. at 1527-28
     (quoting 
    42 U.S.C. § 7415
    (a) (1982)) (omission
    in original). Petitioners alleged that the Administrator acted
    unreasonably in holding off making an endangerment finding as
    to acid rain, which strong evidence (including informal EPA
    statements) indicated was coming from the United States and
    endangering Canadian welfare. 
    Id. at 1529
    . We held that EPA
    acted reasonably in postponing a formal endangerment finding
    only because it gave a reasonable statutory basis for doing so.
    Specifically, because EPA still lacked information as to which
    states were causing the harmful acid rain, it would have been
    “pointless” for the agency to make an endangerment finding
    given the “specific [statutory] linkage between the
    endangerment finding and the remedial procedures,” i.e.,
    notifying offending states. 
    Id. at 1533
    . “For this reason,” we
    found EPA’s decision to postpone an endangerment finding
    “both reasonable and consistent with the statute.” 
    Id.
    In short, EPA may withhold an endangerment finding only
    if it needs more information to determine whether the statutory
    29
    standard has been met. Similarly, for EPA to find no
    endangerment (as Judge Randolph, going beyond the agency’s
    own arguments, appears to claim happened here, see op. of
    Randolph, J., at 13, 15), it must ground that conclusion in the
    statutory standard and may not rely on unrelated policy
    considerations.
    The statutory standard, moreover, is precautionary. At the
    time we decided Ethyl, section 202(a)(1) and similar CAA
    provisions either authorized or required the Administrator to act
    on finding that emissions led to “air pollution which endangers
    the public health or welfare.” See 42 U.S.C. § 1857f-1(a)(1)
    (1976) (emphasis added). After Ethyl found that “the statutes
    and common sense demand regulatory action to prevent harm,
    even if the regulator is less than certain that harm is otherwise
    inevitable,” Ethyl, 
    541 F.2d at 25
     (emphasis added), the 1977
    Congress not only approved of this conclusion, see H.R. Rep.
    No. 95-294, at 49, but also wrote it into the CAA. Section
    202(a)(1) (along with other provisions, see H.R. Rep. No. 95-
    294, at 50) now requires regulation to precede certainty. It
    requires regulation where, in the Administrator’s judgment,
    emissions “contribute to air pollution which may reasonably be
    anticipated to endanger public health or welfare.” 
    42 U.S.C. § 7521
    (a)(1) (emphasis added). As the House Report explained:
    “In order to emphasize the precautionary or preventative
    purpose of the act (and, therefore, the Administrator’s duty to
    assess risks rather than wait for proof of actual harm), the
    committee not only retained the concept of endangerment to
    health; the committee also added the words ‘may reasonably be
    anticipated to.’” H.R. Rep. No. 95-294, at 51 (emphasis added).
    Given this framework, it is obvious that none of EPA’s
    proffered policy reasons justifies its refusal to find that GHG
    emissions “contribute to air pollution which may reasonably be
    anticipated to endanger public health or welfare.” Unlike in Her
    Majesty the Queen, EPA’s proffered reasons for refusing to
    30
    make an endangerment finding have no connection to the
    statutory standard. Instead, as in Natural Resources Defense
    Council (where we found EPA to have acted arbitrarily and
    capriciously), EPA has “ventured into a zone of impermissible
    action” by “simply substitut[ing]” freestanding policy concerns
    for the sort of evaluation required by the statute. See 
    824 F.2d at 1163
    . A look at these policy concerns proves the point.
    First, EPA claims that global warming still has many
    scientific uncertainties associated with it. See 68 Fed. Reg. at
    52,930-31; see also op. of Randolph, J., at 11-13. In this regard,
    EPA makes much of the NRC’s statements that a link between
    human-caused atmospheric GHG concentration increases and
    this past century’s warming “cannot be unequivocally
    established”; that “a wide range of uncertainty” remains
    “inherent in current model predictions” due to imprecise
    variables like future emissions rates, climate sensitivity, and the
    forcing effects of aerosols; and that “current estimate [sic] of the
    magnitude of future warming should be regarded as tentative
    and subject to future adjustments (either upward or downward).”
    See 68 Fed. Reg. at 52,930 (quoting NRC Rep. at 1, 17); see
    also op. of Randolph, J., at 11-13. But the CAA nowhere calls
    for proof. It nowhere calls for “unequivocal” evidence. Instead,
    it calls for the Administrator to determine whether GHGs
    “contribute to air pollution which may reasonably be anticipated
    to endanger” welfare. EPA never suggests that the uncertainties
    identified by the NRC Report prevent it from determining that
    GHGs “may reasonably be anticipated to endanger” welfare. In
    other words, just as EPA failed in Natural Resources Defense
    Council to explain its chosen emissions level in light of the
    statutory standard, so the agency has failed here to explain its
    refusal to find endangerment in light of the statutory standard.
    EPA’s silence on this point is telling. Indeed, looking at the
    NRC Report as a whole, I doubt EPA could credibly conclude
    that it needs more research to determine whether GHG-caused
    31
    global warming “may reasonably be anticipated to endanger”
    welfare. Though not offering certainty, the report demonstrates
    that matters are well within the “frontiers of scientific
    knowledge,” see op. of Randolph, J., at 15 (quoting Envtl. Def.
    Fund v. EPA, 
    598 F.2d 62
    , 82 (D.C. Cir. 1978)). The report also
    indicates that the projected consequences of global warming are
    serious.     Because neither EPA nor Judge Randolph
    acknowledges, let alone evaluates, these projected effects, I
    quote the NRC’s discussion of the “Consequences of Increased
    Climate Change of Various Magnitudes” in its entirety.
    The U.S. National Assessment of Climate Change
    Impacts, augmented by a recent NRC report on climate and
    health, provides a basis for summarizing the potential
    consequences of climate change. The National Assessment
    directly addresses the importance of climate change of
    various magnitudes by considering climate scenarios from
    two well-regarded models (the Hadley model of the United
    Kingdom and the Canadian Climate Model). These two
    models have very different globally-averaged temperature
    increases (2.7 and 4.4º C (4.9 and 7.9º F), respectively) by
    the year 2100. A key conclusion from the National
    Assessment is that U.S. society is likely to be able to adapt
    to most of the climate change impacts on human systems,
    but these adaptations may come with substantial cost. The
    primary conclusions from these reports are summarized for
    agriculture and forestry, water, human health, and coastal
    regions.
    In the near term, agriculture and forestry are likely to
    benefit from CO2 fertilization effects and the increased
    water efficiency of many plants at higher atmospheric CO2
    concentrations. Many crop distributions will change, thus
    requiring significant regional adaptations. Given their
    resource base, the Assessment concludes that such changes
    will be costlier for small farmers than for large corporate
    32
    farms. However, the combination of the geographic and
    climatic breadth of the United States, possibly augmented
    by advances in genetics, increases the nation’s robustness
    to climate change. These conclusions depend on the
    climate scenario, with hotter and drier conditions increasing
    the potential for declines in both agriculture and forestry.
    In addition, the response of insects and plant diseases to
    warming is poorly understood. On the regional scale and in
    the longer term, there is much more uncertainty.
    Increased tendency towards drought, as projected by
    some models, is an important concern in every region of the
    United States even though it is unlikely to be realized
    everywhere in the nation. Decreased snow pack and/or
    earlier season melting are expected in response to warming
    because the freeze line will be moving to higher elevations.
    The western part of the nation is highly dependent on the
    amount of snow pack and the timing of the runoff. The
    noted increased rainfall rates have implications for
    pollution run-off, flood control, and changes to plant and
    animal habitat. Any significant climate change is likely to
    result in increased costs because the nation’s investment in
    water supply infrastructure is largely tuned to the current
    climate.
    Health outcomes in response to climate change are the
    subject of intense debate. Climate change has the potential
    to influence the frequency and transmission of infectious
    disease, alter heat- and cold-related mortality and
    morbidity, and influence air and water quality. Climate
    change is just one of the factors that influence the frequency
    and transmission of infectious disease, and hence the
    assessments view such changes as highly uncertain. This
    said, changes in agents that transport infectious diseases
    (e.g., mosquitoes, ticks, rodents) are likely to occur with
    any significant change in precipitation and temperature.
    33
    Increases in mean temperatures are expected to result in
    new record high temperatures and warm nights and an
    increase in the number of warm days compared to the
    present. Cold-related stress is likely to decline whereas
    heat stress in major urban areas is projected to increase if
    no adaptation occurs. The National Assessment ties
    increases in adverse air quality to higher temperatures and
    other air mass characteristics. However, much of the
    United States appears to be protected against many different
    adverse health outcomes related to climate change by a
    strong public health system, relatively high levels of public
    awareness, and a high standard of living. Children, the
    elderly, and the poor are considered to be the most
    vulnerable to adverse health outcomes. The understanding
    of the relationships between weather/climate and human
    health is in its infancy and therefore the health
    consequences of climate change are poorly understood.
    The costs, benefits, and availability of resources for
    adaptation are also uncertain.
    Fifty-three percent of the U.S. population lives within
    the coastal regions, along with billions of dollars in
    associated infrastructure. Because of this, coastal areas are
    more vulnerable to increases in severe weather and sea level
    rise. Changes in storm frequency and intensity are one of
    the more uncertain elements of future climate change
    prediction. However, sea level rise increases the potential
    damage to coastal regions even under conditions of current
    storm intensities and can endanger coastal ecosystems if
    human systems or other barriers limit the opportunities for
    migration.
    In contrast to human systems, the U.S. National
    Assessment makes a strong case that ecosystems are the
    most vulnerable to the projected rate and magnitude of
    climate change, in part because the available adaptation
    34
    options are very limited. Significant climate change will
    cause disruption to many U.S. ecosystems, including
    wetlands, forests, grasslands, rivers, and lakes. Ecosystems
    have inherent value, and also supply the country with a
    wide variety of ecosystem services.
    The impacts of these climate changes will be
    significant, but their nature and intensity will depend
    strongly on the region and timing of the occurrence. At a
    national level, the direct economic impacts are likely to be
    modest. However, on a regional basis the level and extent
    of both beneficial and harmful impacts will grow. Some
    economic sectors may be transformed substantially and
    there may be significant regional transitions associated with
    shifts in agriculture and forestry. Increasingly, climate
    change impacts will have to be placed in the context of
    other stresses associated with land use and a wide variety of
    pollutants. The possibility of abrupt or unexpected changes
    could pose greater challenges for adaptation.
    Even the mid-range scenarios considered in the IPCC
    result in temperatures that continue to increase well beyond
    the end of this century, suggesting that assessments that
    examine only the next 100 years may well underestimate
    the magnitude of the eventual impacts. For example a
    sustained and progressive drying of the land surface, if it
    occurred, would eventually lead to desertification of regions
    that are now marginally arable, and any substantial melting
    or breaking up of the Greenland and Antarctic ice caps
    could cause widespread coastal inundation.
    NRC Rep. at 19-20 (footnotes omitted). I have grave difficulty
    seeing how EPA, while treating the NRC Report as an
    “objective and independent assessment of the relevant science,”
    68 Fed. Reg. at 52,930, could possibly fail to conclude that
    global warming “may reasonably be anticipated to endanger
    public health or welfare,” 
    42 U.S.C. § 7521
    (a)(1), with effects
    35
    on welfare including “effects on soil, water, crops, vegetation,
    manmade materials, animals, wildlife, weather, visibility, and
    climate, damage to and deterioration of property, and hazards to
    transportation, as well as effects on economic values and on
    personal comfort and well-being,” 
    id.
     § 7602(h). It thus comes
    as no surprise that EPA’s petition denial not only undertakes
    none of the risk assessments described in Ethyl, 
    541 F.2d at
    28
    & n.58, but also utterly ignores the statutory standard.
    EPA similarly fails to link its second policy
    justification—that setting fuel economy standards represents the
    only currently available way to regulate CO2 emissions and
    petitioners “make no suggestion[s]” for how to reduce CH4,
    N2O, and HFC emissions, 68 Fed. Reg. at 52,931—with the
    statutory standard. As discussed earlier, supra at 21-22, the fact
    that DOT sets fuel economy standards pursuant to the EPCA in
    no way prevents EPA from setting standards pursuant to the
    CAA. It is true that DOT has recently increased fuel economy
    standards for light trucks, see 68 Fed. Reg. at 52,931; see also
    op. of Randolph, J., at 14—a fact EPA did not even bother to
    mention in its brief—but unless DOT’s action affects whether
    GHGs “contribute to air pollution which may reasonably be
    anticipated to endanger public health or welfare,” it provides no
    support for EPA’s decision.
    As to EPA’s point about other GHGs, it may well be that no
    current technologies exist for reducing their emissions. But
    once again, this has nothing at all to do with the statutory
    endangerment standard. Indeed, in section 202(a)(2), Congress
    has made it crystal clear that endangerment findings must not
    wait on technology.
    Any regulation prescribed under paragraph (1) of this
    subsection (and any revision thereof) shall take effect after
    such period as the Administrator finds necessary to permit
    the development and application of the requisite
    36
    technology, giving appropriate consideration to the cost of
    compliance within such period.
    
    42 U.S.C. § 7521
    (a)(2). As the Senate Report explained, EPA
    “is expected to press for the development and application of
    improved technology rather than be limited by that which
    exists.” S. Rep. No. 91-1196, at 24 (1970); see also Natural
    Res. Def. Council, Inc. v. EPA, 
    655 F.2d 318
    , 328 (D.C. Cir.
    1981) (referencing this legislative history). In refusing to make
    an endangerment finding because it lacks currently available
    technology for controlling these emissions, EPA goes well
    beyond the bounds of its statutory discretion.
    EPA’s final policy reasons likewise fail. Because other
    domestic and foreign sources contribute to atmospheric GHG
    concentrations, GHG regulation might well “result in an
    inefficient, piecemeal approach to addressing the climate change
    issue,” 68 Fed. Reg. at 52,931. But again, Congress has
    expressly demanded such an approach. Section 202(a)(1)
    requires EPA to regulate if it judges that U.S. motor vehicle
    emissions “cause, or contribute to, air pollution,” 
    42 U.S.C. § 7521
    (a)(1) (emphasis added); see also Ethyl, 
    541 F.2d at 29-31
    (holding that the same language from section 211 plainly means
    that emissions merit regulation even if they are not the only
    source of air pollution). EPA (understandably) offers no basis
    for thinking that U.S. automobile emissions are not contributing
    to global warming. Indeed, why would the “Administration’s
    global climate change policy plan support[] increasing
    automobile fuel economy,” see 68 Fed. Reg. at 52,933, if motor
    vehicle emissions were contributing nothing to global warming?
    Similarly, EPA’s concern that regulation could weaken U.S.
    negotiating power with other nations has nothing at all to do
    with whether GHGs contribute to welfare-endangering air
    pollution. Finally, while EPA obviously prefers nonregulatory
    approaches to regulatory ones, see id. at 52,932-33, Congress
    gave the Administrator discretion only in assessing whether
    37
    global warming “may reasonably be anticipated to endanger”
    welfare, not “free[dom] to set policy on his own terms,” Ethyl,
    
    541 F.2d at 29
    .
    In short, EPA has utterly failed to relate its policy reasons
    to section 202(a)(1)’s standard. Indeed, nowhere in its policy
    discussion does EPA so much as mention this standard—“may
    reasonably be anticipated to endanger public health or welfare.”
    See 68 Fed. Reg. at 52,929-33 (the sections titled “Different
    Policy Approach” and “Administration Global Climate Change
    Policy”). EPA apparently dislikes the fact that section 202(a)(1)
    says the Administrator “shall” regulate—rather than “may”
    regulate—on making an endangerment finding. But EPA cannot
    duck Congress’s express directive by declining to evaluate
    endangerment on the basis of policy reasons unrelated to the
    statutory standard. Although EPA is free to take its policy
    concerns to Congress and seek a change in the Clean Air Act, it
    must obey the law in the meantime.
    EPA’s Discretion After Making an Endangerment Finding
    Alternatively, EPA may have believed that even if it made
    an endangerment finding, it had no obligation to regulate GHG
    emissions. The petition denial states,
    EPA also disagrees with the premise of the petitioners’
    claim—that if the Administrator were to find that GHGs, in
    general, may reasonably be anticipated to endanger public
    health or welfare, she must necessarily regulate GHG
    emissions from motor vehicles. Depending on the
    particular problem, motor vehicles may contribute more or
    less or not at all. An important issue before the
    Administrator is whether, given motor vehicles’ relative
    contribution to a problem, it makes sense to regulate them.
    . . . The discretionary nature of the Administrator’s section
    202(a)(1) authority allows her to consider these important
    policy issues and decide to regulate motor vehicle
    38
    emissions as appropriate to the air pollution problem being
    addressed. Accordingly, even were the Administrator to
    make a formal finding regarding the potential health and
    welfare effects of GHGs in general, section 202(a)(1) would
    not require her to regulate GHG emission from motor
    vehicles.
    68 Fed. Reg. at 52,929. This passage is puzzling. Motor
    vehicles emit GHGs in significant quantities, see U.S. Dep’t of
    State, U.S. Climate Action Report 2002, at 40—a point EPA
    nowhere contests.        The statute clearly states that the
    Administrator “shall by regulation prescribe . . . standards”
    governing the emissions of air pollutants from motor vehicles if
    the Administrator makes an endangerment finding regarding
    these pollutants. 
    42 U.S.C. § 7521
    (a)(1) (emphasis added).
    Compare 
    id.
     § 7545(c)(1)(A) (using “may”). Refusing to
    regulate following an endangerment finding would violate the
    law. Indeed, EPA appears to have abandoned this argument. In
    a (rare) concession to the Act’s text, EPA counsel acknowledged
    at oral argument, “I don’t think that we would contest that if the
    agency had made an endangerment finding, that then you would
    have to give some significance to the term ‘shall’ in [section]
    202(a).” Tr. of Oral Arg. at 44.
    V.
    Although this case comes to us in the context of a highly
    controversial question—global warming—it actually presents a
    quite traditional legal issue: has the Environmental Protection
    Agency complied with the Clean Air Act? For the reasons given
    above, I believe that EPA has both misinterpreted the scope of
    its statutory authority and failed to provide a statutorily based
    justification for refusing to make an endangerment finding. I
    would thus grant the petitions for review.
    

Document Info

Docket Number: 03-1361

Filed Date: 7/15/2005

Precedential Status: Precedential

Modified Date: 12/21/2014

Authorities (35)

engine-manufacturers-association-on-behalf-of-certain-of-its-members-v , 88 F.3d 1075 ( 1996 )

her-majesty-the-queen-in-right-of-ontario-ian-g-scott-qc-attorney , 912 F.2d 1525 ( 1990 )

Newman v. United States Ex Rel. Frizzell , 35 S. Ct. 881 ( 1915 )

Pension Benefit Guaranty Corporation v. LTV Corp. , 110 S. Ct. 2668 ( 1990 )

Whitman v. American Trucking Assns., Inc. , 121 S. Ct. 903 ( 2001 )

PGA Tour, Inc. v. Martin , 121 S. Ct. 1879 ( 2001 )

Tyler v. Judges of the Court of Registration , 21 S. Ct. 206 ( 1900 )

Indep Equip Dlrs v. EPA , 372 F.3d 420 ( 2004 )

motor-vehicle-manufacturers-association-of-the-united-states-inc-v , 768 F.2d 385 ( 1985 )

Consum Elec Assn v. FCC , 347 F.3d 291 ( 2003 )

Chevron U. S. A. Inc. v. Natural Resources Defense Council, ... , 104 S. Ct. 2778 ( 1984 )

Food & Drug Administration v. Brown & Williamson Tobacco ... , 120 S. Ct. 1291 ( 2000 )

Nuclear Energy Institute, Inc. v. Environmental Protection ... , 373 F.3d 1251 ( 2004 )

United States v. Estate of Romani , 118 S. Ct. 1478 ( 1998 )

Steel Co. v. Citizens for a Better Environment , 118 S. Ct. 1003 ( 1998 )

Teva Pharmaceutical Industries Ltd. v. Crawford , 410 F.3d 51 ( 2005 )

Sierra Club v. Environmental Protection Agency , 292 F.3d 895 ( 2002 )

natural-resources-defense-council-inc-v-us-environmental-protection , 824 F.2d 1146 ( 1987 )

Morton v. Mancari , 94 S. Ct. 2474 ( 1974 )

Ctzn Coal Cncl v. Norton, Gale A. , 330 F.3d 478 ( 2003 )

View All Authorities »