In a major victory for advocates of regulatory action to address climate change, the Court of Appeals for the District of Columbia Circuit rejected challenges to the listing of the polar bear as a threatened species.  In Re:  Polar Bear Endangered Species Listing and Section 4(d) Rule Litigation (D.C. Cir. No. 11-5219, March 1, 2013).  The court held that the decision to list the polar bear based on predicted reductions in the sea ice habitat of the polar bear as a result of climate change is reasonable and adequately supported by the record.
The polar bear listing is the first and most high profile example of the use of the Endangered Species Act to force the federal government to adopt regulations addressing climate change.  Environmental organizations have sought to list several other species under the ESA based on potential climate change impacts on the species.  The petitioners for the listing of the polar bear have indicated their intention to use the regulatory protections provided by the ESA to challenge fossil fuel development and other activities with material greenhouse gas emissions.
Among several other arguments, the State of Alaska and other opponents of the listing argued that the U.S. Fish and Wildlife Service (Service) improperly used determinations by the Intergovernmental Panel on Climate Change (IPCC) in the evaluation of the likelihood of survival of the polar bear.  The court concluded that while the Service relied on the IPCC climate forecasts, the Service did not bind itself to the IPCC determinations to evaluate the survival of the polar bear.