The U.S. Supreme Court handed down judgment in American Electric Power Co., Inc. v. Connecticut on 20 June 2011. In this case The States of California, Connecticut, Iowa, New York, Rhode Island, and Vermont sued five utilities: American Electric Power, Southern Co, Excel Energy, Duke Energy and the government owned Tennessee Valley Authority in public nuisance. The Supreme Court ruled that there was no cause of action in the federal common law of nuisance to combat emissions of carbon dioxide, any such right having been displaced by the Clean Air Act and the actions taken thereunder by the US EPA.
In 2007, in Massachusetts v. EPA (549 U.S. 497 (2007)), the Supreme Court held that the EPA had a duty to employ its powers under the Clean Air Act and assess whether greenhouse gas emissions were a danger to the environment and, if that was the case, to regulate them. Thereafter the EPA pledged to undertake the regulation of carbon dioxide emissions. Using the Clean Air Act regime, it issued an “Endangerment Ruling” (76 Fed. Reg.66496). The Ruling pointed to the possibility of heat related death, more frequent and fierce hurricanes, coastal flooding and the like. It began, a little slowly for some critics, to regulate emissions from such sources as light trucks, medium and heavy-duty vehicles, major industry and fossil-fuel fired power plants.
In the light of these actions, and given the comprehensive framework under the Clean Air Act, in the Connecticut case, the Supreme Court asked whether congressional legislation excluded the declaration of federal common law because the statute fully addresses the problem of GHG emissions. It answered this question by finding that the Clean Air Act, and the EPA actions authorised thereby, displace any federal common law right to GHG emissions from fossil-fuel fired power plants as a nuisance.
The decision seems to suggest that it is the presence of delegated power in favour of the EPA that displaces federal common law. At the same time, however, the decision states that it is reluctant to displace ‘expert determination’ by common law decision-making, suggesting that expert agencies are better equipped to regulate GHG emissions than are judges using case by case remedies. This does seem to suggest room for judicial intervention where no expert determination is taking place.
As a result, although a defeat for the claimant states, this decision may act as a further catalyst for EPA action in the face of political opposition. Congress has threatened on occasions to remove competence over GHG emissions from the EPA. Doing so now might mean that the loss of this expert determination would leave the field open to judicial remedies in federal common law. Moreover, States retain a right to sue under federal common law for pollution disruptions from another State and this may be a source of future climate change litigation; the Court having declined an invitation by the defendants to overrule this line of authority.
In summary, the US Supreme Court has ruled that the presence of Clean Air Act powers displace the possibility of a federal public nuisance action, but this may emphasise the need to employ such powers. The case of American Electric Power Co., Inc. v. Connecticut represents a defeat for climate change litigants in this particular battle, but it does not yet, at least, signal an end to the war.