The U.S. Supreme Court on Monday agreed to hear challenges from five major power companies on a federal appeals court decision that ruled they could be sued, under a federal “public nuisance” law, to curb greenhouse gas emissions, which allegedly cause entity-harming climate changes. Industry experts say the case will likely be heard by the high court next April, and a decision could be made as early as June.

In Connecticut et al., v. American Electric Power Corp., 582 F.3d 309 (2d Cir. 2009), the Second Court of Appeals in September 2009 reversed a district court ruling and rejected a variety of defenses asserting that climate change–related damages raise “political questions” and are thus not suitable for judicial resolution.

The lawsuit, brought against American Electric Power (AEP), Southern Co., Duke Energy, Xcel Energy, and the Tennessee Valley Authority (TVA) by eight states, the City of New York, and three private land trusts, sought an injunction requiring emission-reductions from fossil fuel–fired facilities owned by the defendants. The plaintiffs in that case had cited a variety of climate change–related injuries, saying carbon dioxide emitted by the power plants constituted a “public nuisance.”

The U.S. District Court of the Southern District of New York had in 2005 dismissed the case, saying claims presented a “political question,” which the court did not have the jurisdiction to decide. But in September 2009, a two-judge panel of the U.S. Court of Appeals for the Second Circuit reversed the district court’s decision in a 139-page opinion, rejecting the defendant’s claim that the litigation presented a “political question.”

The power companies—supported by the Obama administration, which filed a separate brief on behalf of the federally owned TVA—in August 2010 petitioned the U.S. Supreme Court to hear the case.

According to industry experts, the Supreme Court’s review of the federal court decision will be limited to issues related to whether federal courts have  jurisdiction over the dispute and the viability of the plaintiffs’ claims under federal law.

“The Court will also need to decide whether the plaintiffs have standing to sue — in other words whether they are proper plaintiffs who have the right to bring the case,” wrote Anne Carlson of UCLA’s Berkeley Law School. “One reason standing is so important is because what the Court has to say about standing in AEP v. Conn. will matter a lot to any future case involving climate change. So the case promises to have repercussions far beyond the substantive issue in this case.”

The case now proceeds under Supreme Court rules and oral arguments could be heard as early as next spring. Eight of the nine Supreme Court justices will consider the case because Justice Sonia Sotomayor, who was a member of the appellate court panel that reversed the district court decision, has recused herself. This means that the court could be split 4–4 on the issue, experts say.

Four of the eight justices dissented in Massachusetts v. EPA (2007), a landmark case which held that greenhouse gases could be regulated under the Clean Air Act if the federal Environmental Protection Agency (EPA) found them to endanger public health and welfare.

The EPA moved to regulate greenhouse gas emissions from stationary sources after the Second Circuit Court’s decision in 2009. This could mean, according to experts, that the Supreme Court could also possibly remand the case back to the appellate court for further briefing on whether the new regulations could displace federal nuisance laws as they relate to climate change.

Sources: POWER, POWERnews, U.S. Supreme Court, Berkeley Law School