On May 14, the U.S. Court of Appeals for the Fifth Circuit affirmed a lower court’s dismissal of a lawsuit brought by a group of Mississippi Gulf Coast residents and property owners against energy companies whose emissions they alleged contributed to global warming, which intensified Hurricane Katrina, which, in turn, damaged their property. The Fifth Circuit held that the plaintiffs’ claims were barred by the doctrine of res judicata, which bars the re-litigation of a claim that has been decided on the merits in a prior action.

The case presented an unusual procedural situation. Plaintiffs originally brought their claims in Mississippi federal court in 2005. The district court dismissed the case, and a panel of the Fifth Circuit reversed and remanded, in part, the district court’s decision. Before the panel opinion’s mandate issued, six of this court’s nine active, unrecused judges voted to rehear the case en banc, thus vacating the panel’s opinion. However, before the en banc court reheard the case, an additional judge was recused, leaving the Fifth Circuit without a quorum (eight of the court’s sixteen active judges having been recused). Because it lacked a quorum, the court dismissed the appeal.

After unsuccessfully seeking Supreme Court review, the plaintiffs filed a new complaint asserting substantially similar claims in the same district court in 2011. The district court dismissed the claims on several grounds, including res judicata. The Fifth Circuit affirmed, holding that although the original district court decision was never subject to meaningful appellate review, it still constituted a final judgment on the merits for purposes of res judicata.

The case is Comer v Murpy Oil USA, Inc., No. 12-60291 (5th (Cir.).