In a major 5-4 ruling, the Supreme Court decided 4/2/2007 that the EPA must reconsider its decision not to issue new motor vehicle emission standards under its authority under section 202(a)(1) of the Clean Air Act, relating to the regulation of air pollutants associated with global climate change. Under that section, the EPA Administrator must regulate air pollutants when, “in his judgment,” such pollutants “may reasonably be anticipated to endanger public health or welfare.” 42 U.S.C. § 7521(a)(1). Several parties petitioned the EPA to set regulatory standards for air pollutants associated with climate change. The EPA denied the petition, concluding that it lacked authority to do so, and that, even if it had authority, it would deny the petition based on various policy considerations not expressly addressed in the statute, including scientific uncertainties, the inefficiency of piecemeal approaches to the climate change issue, and foreign policy concerns.
The D.C. Circuit upheld the EPA’s decision, but the Supreme Court reversed. The majority ruled that the 11 states that filed suit had standing to sue because the standing requirements for challenging agency action unlawfully withheld are not as strict as regular standing requirements. The states need only show that they have suffered a "concrete and particularized injury," but not that the injury is immediate or that a favorable decision will redress that injury. Because the states have a procedural right to protect their interests, they have standing "if there is some possibility that the requested relief will prompt the injury-causing party to reconsider the decision that allegedly harmed the litigant." It also ruled that states are entitled to special treatment because they have given up some of their sovereign powers to the federal government.
It ruled that Massachusetts will suffer injury to coastal land that it owns, and since EPA did not dispute the existence of a causal connection between man-made greenhouse gas emissions and global warming, EPA's refusal to regulate such emissions contributes to that state's injuries. EPA cannot refuse to regulate just because auto emissions are such a small part of overall greenhouse gas emissions, since many regulations legitimately take incremental steps in addressing massive problems.
The Court held that an agency's denial of a petition for rulemaking is susceptible to "extremely limited" and "highly deferential" judicial review. It found that the plain language of the Clean Air Act defines "air pollutant" to include all airborne compounds of any kind, and regulating the quality of the air does not conflict with the Department of Transportation's authority to regulate automobile efficiency.
Finally, the Court ruled that the Clean Air Act requires EPA to form a judgment on whether greenhouse gases contribute to air pollution that may reasonably be anticipated to endanger public health or welfare. Once it has found such endangerment, it has "significant latitude as to the manner, timing, content, and coordination of its regulations with those of other agencies." To avoid having to impose some regulations, it must either determine that greenhouse gases do not contribute to climate change, or provide some reasonable explanation as to why it cannot or will not exercise its discretion to determine whether they do. Thus, the Court left open the possibility that EPA could withhold regulation, but only if it grounds its reasons for inaction in the Clean Air Act.
Justices Roberts, Scalia, Thomas and Alito dissented in part because they felt the states did not have standing, and that the Court's new rule giving states preferential treatment has no basis in existing case law. The majority cited a 1907 case that did not involve standing and that neither the states nor any of the supporting briefs mentioned. The dissent argues that a particularized injury to Massachusetts has not been shown, since the affidavits in support of that claim suggest that land subsidence, a non-global-warming cause, is affecting Boston's rising sea level. Injury is not imminent or certainly impending, and a computer model's conceded average error rate is greater than or equal to the projected sea level rise. The alleged connection between the fractional amount of global emissions that might be limited with EPA standards and the loss of Massachusetts coastal land is far too speculative to establish causation. Furthermore, a regulation is not likely to redress Massachusetts' injury, since it will have no proven effect on the voluminous amount of greenhouse gases emitted elsewhere in the world. Referring to a 1973 decision in United States v. Students Challenging Regulatory Agency Procedures (SCRAP), Chief Justice Roberts wrote, "Today's decision is SCRAP for a new generation."
A separate dissent written by Justice Scalia says there is no language in the Clean Air Act that requires EPA to make a judgment on greenhouse gases, and that the Act governs only air pollution, which EPA reasonably decided does not include carbon dioxide high in the atmosphere.
The NAM is part of the CO2 Coalition, which participated in this case in the D.C. Circuit and the Supreme Court. The decision granting standing to states to challenge federal agency action, or inaction, without the same restrictions as other plaintiffs could lead to increased litigation by the states against a variety of federal agency decisions.