As climate legislation stagnates in Congress, the possibility of greenhouse gas ("GHG") regulation under the Environmental Protection Agency's ("EPA") existing Clean Air Act authority as the sole federal means of addressing climate change becomes increasingly likely.  Whether EPA has existing authority to implement a cap-and-trade program for GHGs, which many believe is the cornerstone of an effective and efficient approach to controlling emissions, has as yet no definitive answer.  The various sections of the Clean Air Act that could act as authority for such a program have their own legal ambiguities and practical limitations. One largely overlooked section-§ 115 on "International Air Pollution"-however, is potentially quite powerful in its implications for the establishment of a cap-and-trade program.

In the fall of 2009, the Second Circuit issued its long-awaited decision in Connecticut v. American Electric Power Company, a case alleging a federal common law nuisance claim based on the effects of greenhouse gases.  The Second Circuit Court of Appeals reversed a lower court dismissal of the case.  In a lengthy opinion, the Second Circuit held that plaintiffs-eight states, the City of New York, and three nonprofit entities-had standing to seek an injunction against six electrical utility companies to restrict their greenhouse gas emissions based on a public nuisance claim.  The Court also held that the claims were not barred by the political question doctrine, which forecloses courts from deciding questions that have been committed for decision to the executive and legislative branches.  Finally, the Court held that plaintiffs had stated a viable federal common law nuisance claim, which had not been displaced by congressional or regulatory action.