Eight states, New York City, and three land trusts sued five electric power companies claiming the power plants’ carbon dioxide emissions contributed to global warming and violated the federal common law of interstate nuisance. Plaintiffs asked the federal district court to set carbon dioxide emission caps on the power plants.
Per Erie R. Co. v. Tompkins, the federal courts must abide by state decisions â€œon matters of substantive law appropriately cognizable by the states.â€ Federal common law is preempted when there is a federal statute addressing an issue central to a federal lawsuit. Per Milwaukee v. Illinois, when Congress has enacted a federal statute on a matter previously addressed by a decision based upon federal common law, â€œthe need for such an unusual exercise of law-making by federal courts disappears.â€
Plaintiffs include eight states, New York City, and three non-profit land trusts. Defendants are four private electric power companies and the federally owned Tennessee Valley Authority. Defendants owned and operated fossil-fuel-fired power plants in multiple states. Plaintiffs separately filed lawsuits against Defendants in federal district court claiming Defendants’ power plants’ emission of carbon dioxide contributed to global warming and that these emissions substantially and unreasonably interfered with public rights, therefore violating the federal common law of interstate nuisance, or state tort law. Plaintiffs sought injunctive relief in the form of carbon dioxide emission caps and further specific reductions each year for at least 10 years. The United States District Court for the Southern District of New York found these were non-justiciable questions per the political questions doctrine and dismissed. Plaintiffs appealed. United States Court of Appeals of the Second Circuit vacated and remanded, finding the federal common law was not displaced by the Clean Air Act, noting specifically that the Environmental Protection Agency did not yet have a rule in place to regulate greenhouse gases. United States Supreme Court granted certiorari.
Whether the Plaintiffs could successfully maintain a cause of action against Defendants under federal common law public nuisance.
The Clean Air Act and its authorization of action by the EPA displaces the Plaintiffs’ federal common law claims. Whether a claim is available under state nuisance law is a matter for consideration on remand. Reversed and remanded.
Justice Alito concurs in part and concurs in the judgment (Justice Thomas joins).
Although per Erie there is no general federal common law, under â€œnewâ€ federal common law it has become appropriate when matters of national concern are at issue and covers â€œsubjects within national legislative power where Congress has so directed.â€ The protection of our environment has been one example of this. The United States Supreme Court has approved such federal common law causes of action by states attempting to decrease pollution caused by another state. In Massachusetts v. EPA, the United States Supreme Court held federal regulation of carbon dioxide/other greenhouse gasses was authorized by the Clean Air Act. Therefore, Plaintiffs proper course of action would be to petition the EPA, not the courts, to make a rule to handle their issue of the power plants’ emissions.