In Comer v Murphy Oil USA, et al, the Fifth Circuit Court of Appeals refused to dismiss a lawsuit brought by private citizens against alleged polluters for property damage allegedly caused or worsened by global warming. In Comer, Mississippi Gulf residents sued a variety of energy and chemical companies for damages caused by Hurricane Katrina. The plaintiffs claimed that the greenhouse gases produced by the defendants caused a rise in sea levels that made Hurricane Katrina more severe. They asserted a variety of common law tort claims based on damage to their own private property, as well as to certain public property useful to them. The claims included nuisance, trespass and negligence.

The defendants moved to dismiss plaintiffs’ claims, arguing that the hurricane damage was not fairly traceable to defendants’ actions and therefore the plaintiffs lacked standing to bring their claims. The court rejected this argument with respect to the nuisance, trespass and negligence claims and found that, taking the plaintiffs’ allegations, which included references to scientific reports, as true, a sufficient link was alleged. Defendants also argued that the political question doctrine prohibited the court from ruling on the claims. However, the court held that the claims did not present a question exclusively committed to the discretion of the legislative or executive branches, noting that the case involves state law tort actions for damages. The Fifth Circuit therefore reversed the district court’s granting of the motion to dismiss. The October 2009 Comer ruling followed a similar September 2009 decision by the Second Circuit in Connecticut v. American Electric Power Co.