Clean Air Act Preemption of State Common Law: Greenhouse Gas Nuisance Claims After AEP v. Connecticut

In American Electric Power Co. v. Connecticut (AEP), the Supreme Court held that the Clean Air Act displaces federal common law tort claims related to greenhouse gas emissions. This decision effectively signaled the end of a series of public nuisance lawsuits invoking the federal common law as a means of redressing the effects of global warming. While nuisance claims based on state common law could serve as a replacement, their viability depends on an important threshold question: whether, or to what extent, such claims are preempted by the Clean Air Act. This is an issue the Supreme Court raised, but declined to reach, in AEP, and it remains one of the most important questions for the future of greenhouse gas litigation. 

This Note addresses that issue by arguing that the Clean Air Act preempts only one variety of state-law nuisance claims: those brought pursuant to the law of a state other than that where the relevant emissions source is located. Claims brought pursuant to the law of the source state, by contrast, should be able to proceed. As this Note demonstrates, this result is compelled by the structure, text, and purpose of the Clean Air Act, as well as by the Supreme Court’s 1987 decision in International Paper Co. v. Ouellette. At the same time, policy considerations generally counsel against using litigation as a means of regulating greenhouse gas emissions. For this reason, Congress should provide for preemption of all greenhouse-gas-related nuisance claims, regardless of which state’s law applies.