In American Electric Power et al. v. Connecticut et al., six states, the city of New York and three private land trusts sought federal court orders to limit greenhouse gas emissions from power plants operated by private utilities and the Tennessee Valley Authority. The lawsuit was based in part on a federal common law claim of nuisance that argued that the emissions increased the risk to public health and infrastructure through the effects of climate change.
On June 20, 2011, the U.S. Supreme Court decided 8-0, with Justice Sotomayor recused, that the plaintiff's federal common law nuisance claims were displaced by the Clean Air Act, which grants authority to the U.S. Environmental Protection Agency to regulate greenhouse gas emissions. However, the Supreme Court did not resolve the issue of whether the federal court has jurisdiction to hear greenhouse gas emissions lawsuits generally, or whether the Clean Air Act also preempts state court common law claims. As well, the Supreme Court declined to address the question of the causation of climate change.
The decision indicates that the Court will be reluctant to act in the place of regulators, especially for matters that already engage the government process.