A federal appeals court in New Orleans has given the go-ahead for a groundbreaking class-action lawsuit over global warming to proceed.

The case, titled Ned Comer, et al. v. Murphy Oil USA, et al. [pdf], involves a group of residents and landowners along the Mississippi Gulf Coast  who suffered severe property damage during Hurricane Katrina. They allege that the defendants -- energy, fossil fuels and chemical companies -- emitted greenhouse gases that contributed to global warming, which in turn caused a rise in sea levels that increased the storm's ferocity.

The U.S. District Court for the Southern District of Mississippi originally sided with the defendants, who argued that the plaintiffs lacked standing and said their claims presented political questions that did not properly belong in court. The plaintiffs appealed to the Fifth Circuit Court of Appeals, which itself suffered damage in Katrina and had to temporarily move its operations to Houston.

The Fifth Circuit -- considered one of the nation's most conservative -- reversed the district court's judgment, concluding that the plaintiffs have standing to assert their public and private nuisance, trespass and negligence claims. It sent the case back to the district court for further proceedings.

Writing about the case at his blog, professor and National Law Journal columnist Russell Jackson observed:

Comer is particularly important because it is a private class action for compensatory and punitive damages, not a suit brought by states or municipalities for injunctive relief. And that means contingency fees. And thus the promise of copycat lawsuits.

The Fifth Circuit is the second federal appeals court in less than a month to reverse a lower court decision throwing out a climate change lawsuit for presenting a political question, with the other being the Second Circuit Court of Appeal's ruling in Connecticut v. American Electric Power. That case involved a suit originally brought in 2004 by eight states and New York City and later joined by several land trusts. The targets of the suit are American Electric Power of Ohio, the Southern Co. of Atlanta, the federal Tennessee Valley Authority, Xcel Energy of Minneapolis, and Cinergy, an Ohio company acquired by North Carolina-based Duke Energy in 2005.

"Although we arrived at our own decision independently," Judge James Dennis wrote in Comer,
"the Second Circuit's reasoning is fully consistent with ours,
particularly in its careful analysis of whether the case requires the
court to address any specific issue that is constitutionally committed
to another branch of government."

In another court ruling in a climate change lawsuit, a U.S. District Court judge recently dismissed a federal public nuisance lawsuit filed by the Alaskan native village of Kivalina against oil, coal and power companies. The ruling in that suit, which sought monetary damages so the Inupiat village could be relocated, concluded the matter was more appropriately left to politicians than judges, PointofLaw.com reports.

(This Federal Emergency Management Agency photo shows the severe damage to the Mississippi coast from Hurricane Katrina.)