In Massachusetts v. EPA, the Supreme Court issued two holdings- the first covered the procedural aspects of the case, and the second addressed the merits. The Court issued a 5-4 decision holding that at least one Petitioner-Massachusetts-had standing to exercise the jurisdiction of the court. The majority reasoned that Massachusetts had "special solicitude" in the Court's standing analysis and that Massachusetts demonstrated the requisite injury-in-fact, traceability, and redressability to establish standing. The Court also ruled 5-4 that the EPA does have the statutory authority to regulate carbon dioxide emissions from new motor vehicles. The majority held that if the EPA elects not to regulate carbon dioxide under the CAA, the reason for refusing must be consistent with the CAA.

The purpose of this Note is twofold: first, to analyze the reasoning used by the majority in determining that Massachusetts had standing and explore the effect that the majority's reasoning will have on future cases; second, to investigate the potential consequences of the Court's decision that carbon dioxide is an air pollutant under the language of the CAA.

In order to analyze the Court's holding in Massachusetts v. EPA, it is necessary to first look at the underlying issue of global warming and the legal background of the CAA. In analyzing the procedural aspects of the case, it is necessary to look at the development of the standing doctrine and particularly its use in environmental cases. Part II of this Note explores the science surrounding climate change. This Part also gives a concise history of the CAA provisions relating to motor vehicle emissions and reviews the prerequisites necessary to establish standing for jurisdictional purposes. Part III discusses the original rulemaking request by the Petitioners to regulate greenhouse gases, and the EPA's denial of this request. Part III also examines the advancement of Massachusetts v. EPA through the Court of Appeals and the Supreme Court. Part IV will analyze the potential implications of the Supreme Court decision in Massachusetts v. EPA exploring (1) the possibility of administrative action and regulation of greenhouse gas emissions under the current CAA; (2) increased pressure on Congress to enact new legislation requiring mandatory reductions in greenhouse gas emissions; (3) increased state and local action to curb greenhouse gas emissions in the absence of federal action; and (4) the ramifications for industry, including the possible establishment of a carbon credit trading scheme.