In what is said to be the first such intervention in a U.S. climate change case, a European environmental group has filed a legal brief backing U.S. EPA's greenhouse gas rules.

ClientEarth, a U.K.-based environmental law nonprofit, filed a joint brief along with the Union of Concerned Scientists and America's Great Waters Coalition in the U.S. Circuit Court of Appeals for the District of Columbia, which is currently considering industry challenges to four major U.S. EPA climate rules.

The brief, filed Aug. 30, defends EPA's "endangerment finding," in which EPA concluded that carbon emissions are harmful and therefore could be regulated.

ClientEarth and its U.S.-based lawyer, Douglas Ruley, say the brief is the first filed by a European group in a U.S. climate change case.

"What it shows is that the world is increasingly desperate for American leadership on this issue," Ruley said.

Part of the brief focuses on the scientific consensus that prompted European leaders to take action and the European Union's attempts to reduce carbon emissions, which are ongoing.

Ruley said it is important for the court to take into account the European perspective on the matter, especially as the conclusion reached by scientists there "strongly supports" the science upon which EPA based its rules.

The fight over the endangerment finding is one of three interlinked cases now being briefed before the appeals court. Argument dates have yet to be scheduled.

Click here to read the brief.