Earlier this month, the U.S. Court of Appeals for the Second Circuit reversed a district court ruling and allowed a previously dismissed lawsuit brought by two groups of plaintiffs, including eight states and New York City, to go forward. State of Connecticut v. American Electric Power Company, Inc., No. 05-5104-CV. The suit, which was brought against American Electric Power Co. and five other leading utility companies (including Southern Company, TVA, Excel Energy, and Cinergy) that own and operate power plants in 20 states, was brought under a common law theory of nuisance that seeks to compel the utilities to cap and reduce their carbon dioxide emissions in view of what they characterized as the “clear scientific consensus” on global warming.

The utilities and supporting amici argued that the district court was correct in dismissing the case because, among other things, the case, in their view, presented non-justiciable political questions that raised separation-of-powers concerns. They stressed that the suit implicates sensitive issues of national and international policy that were more appropriately resolved by the political branches than by a federal court. The Second Circuit rejected these arguments, holding that the complaint successfully raised a state cause of action.

Both sides of the global warming debate will be watching this case closely, since the possibility that plaintiffs could obtain potentially large damages in court could force carbon reductions that politicians may be unwilling to do. Interestingly, former Second Circuit Judge Sonia Sotomayor was on the Second Circuit panel that heard oral argument in 2006. If the case is ever taken up by the Supreme Court, now-Justice Sotomayor will have to assess whether she should recuse herself.