On November 29, 2006, the United States Supreme Court heard oral argument in Massachusetts v. Environmental Protection Agency.[1] James Milkey argued for Petitioners, and Gregory Garre argued for Respondents. The case was before the Court after a divided panel (2-1) of the Court of Appeals for the D.C. Circuit ruled in favor of EPA, upholding the agency's denial of the rulemaking petition.[2] After the D.C. Circuit denied the plaintiffs' petition for rehearing en banc,[3] the Supreme Court granted certiorarion June 26, 2006. The two core issues before the Court were 1) whether EPA has statutory authority to regulate greenhouse gas emissions under section 202(a)(1) of the Clean Air Act,[4] and if so, 2) whether the agency has discretion to decline to issue emissions standards for motor vehicles based on policy considerations not enumerated in the statute. Also in contention was the jurisdictional issue of standing.

At oral argument, several Justices signaled skepticism concerning Petitioners' standing arguments. Justice Scalia seemed especially suspicious as to the imminence of the harm, asking "when is the predicted cataclysm?"[5] Mr. Milkey responded that the harm was ongoing, playing out continuously over a long period of time. Later, Mr. Milkey asserted that the state's harm was imminent in the same sense that "lighting a fuse on a bomb" presents imminent harm.[6] Justice Scalia also questioned whether Massachusetts satisfied the redressability element of standing, suggesting that a six percent reduction in emissions over a number of years might not be sufficient. Chief Justice Roberts echoed that concern with several questions about whether the potential benefits here would be too "small and widely dispersed," as in cases where taxpayers attempt to challenge illegal government expenditures based simply on their individual contributions.[7] Mr. Milkey noted that the state claimed a particularized harm of loss of 200 miles of coastline, and that in the context of global warming even small reductions can be significant.[8] While a reduction in U.S. emissions would not eliminate the injury, Petitioners argued that because "small vertical rises [in sea levels] cause a large loss of horizontal land," even small emissions reductions would reduce the injury enough to satisfy the redressability prong.[9]

Prodded by Justice Kennedy and Justice Ginsburg, Mr. Milkey stressed that Massachusetts has standing as a property owner and also "special standing" in its sovereign capacity. As Justice Ginsburg noted, where the federal government fails to exercise its regulatory responsibility and states are "disarmed from regulating," those states may have a discrete claim based on sovereignty principles.[10]

On the merits, Mr. Milkey stressed that EPA's refusal to regulate greenhouse gases was based on policy considerations not allowed by the statute. While acknowledging that the agency has wide discretion in allocating resources (under background principles of administrative law and the endangerment standard of section 202(a)(1)), Mr. Milkey contended it may not rely on external policy considerations. On this point, Justice Scalia remarked that he viewed carbon dioxide as a "pollutant" only where it is emitted into the ambient air, as opposed to Petitioner's claim that it is a "pollutant" based on secondary effects upon dispersion into the troposphere. Mr. Milkey countered that air pollutants need not cause harm in the ambient air, citing acid rain as a prime example.[11]

Mr. Garre's oral argument opened with probing questions from Justices Ginsburg and Breyer as to whether EPA's denial of authority to regulate may have tainted its subsequent decision not to regulate. Mr. Garre defended the agency's reasoning by noting that EPA never claimed its decision relied on all of its proffered reasons, and that the "substantial scientific uncertainty" surrounding the issue was justification enough.[12]

After arguing that there is no unequivocal connection between greenhouse gases and global warming (in response to questions from Justice Stevens about scientific uncertainty) Mr. Garre segued to the standing issue, focusing on causation and redressability. After Chief Justice Roberts confirmed that the precise amount of emissions reduction at issue is "not a mathematical question" for standing purposes, Justice Souter peppered Mr. Garre with questions as to what specifically the Petitioners must do to show causation and redressability. Justice Souter wondered why, since redressability is a question of "more or less" and not "either/or," it was insufficient to suppose that "some reduction in the [greenhouse] gases will result in some reduction in future [coastline] loss."[13] Justice Souter indicated that such an assumption seemed "intuitively reasonable," and Justice Breyer appeared to agree, asking "[w]hy is it unreasonable to go to an agency and say now you do your part?" in the context of such global problems as ocean dumping and acid rain. Mr. Garre countered that a party cannot establish standing based on predictions of the actions of independent actors not before it, and Chief Justice Roberts boosted that argument by noting that lack of standing to challenge an agency decision does not mean the agency cannot regulate that particular area.

Justice Stevens moved the discussion back to the merits of the case, invoking the Respondents' argument that they lacked authority to regulate greenhouse gases. Mr. Garre argued that EPA had wide discretion as to when it chooses to make an endangerment finding under section 202(a)(1), contending that the statute "does not put a deadline" on the decision.[14] Mr. Garre stressed the agency position that Congress did not intend for it to regulate greenhouse gases because global climate change is not "air pollution." Citing Food & Drug Administration v. Brown & Williamson Tobacco Corp.,[15] Mr. Garre urged the Justices to consider that given the economic implications of greenhouse gas emissions, it was not likely that Congress intended by such simple language for the agency to have regulatory authority in that realm. Moreover, Mr. Garre emphasized, the "unique collective action problem" in the realm of climate change justified the agency's consideration of foreign affairs in its decision.[16]

On rebuttal, Justices Scalia and Breyer inquired as to whether Petitioners would be satisfied with a remand to the agency to redetermine, in light of proper considerations, whether it would exercise its authority. Chief Justice Roberts and Justice Scalia indicated that if remanded, the primary issue would be whether scientific uncertainty was a sufficient basis for the agency to decline to exercise its authority. Both Justices seemed confident that EPA had already stated that uncertainty precluded action. Mr. Milkey argued that EPA never explained why uncertainty matters, and only "looked at what [scientists] don't know without ever looking at what [scientists] do know."[17]