Because the United States has failed to enact comprehensive legislation to address climate change, legal responses to the problem have been sporadic. The Supreme Court ruled in April 2007 that EPA must consider greenhouse gases to be pollutants under the Clean Air Act; however, there are as yet no federal regulations regarding these gases. Therefore, there has been little judicial recourse available to tackle greenhouse gas emissions. Standing, one of the requirements necessary to file suit in a federal court, is typically difficult to prove in climate change actions because of the perceived lack of connection between greenhouse gas emissions and a plaintiff's injury. However, several recent cases have opened the door to climate change litigation by widening the standing requirement. In addition, courts are now requiring government agencies to consider the effects of climate change in environmental impact statements. Recent case law dealing with climate change includes the following important decisions:
Massachusetts v. EPA: The U.S. Supreme Court held that greenhouse gases fit within the Clean Air Act's capacious definition of "air pollutant" and thus may be regulated by the EPA.
Central Valley Chrysler-Jeep v. Goldstone: The Federal District Court for the Central District of California ordered that California may properly enact emissions regulations that are more strict than the federal fuel economy standards.
Mayo Foundation v. Surface Transportation Board: Plaintiffs brought suit challenging the Surface Transportation Board's approval of a new rail line to reach Wyoming coal mines. The 8th Circuit Court of Appeals held that the Surface Transportation Board adequately considered reasonably foreseeable adverse effects of increased coal consumption on climate change.
Center for Biological Diversity v. National Highway Traffic Safety Administration: The 9th Circuit Court of Appeals ruled that the federal government violated the law by ignoring climate change when it set national gas-mileage standards for SUVs and pickup trucks. The court sent the decision back to the NHTSA for a complete environmental review of gas-mileage standards.
Inuit Climate Change Petition: In December 2005, the Inuit people filed a petition with the Inter-American Commission on Human Rights. The petition sought relief from violations of the Inuits' human rights resulting from climate change caused by greenhouse gas emissions from the United States. It focused on the U.S. because this nation has historically been the largest emitter of greenhouse gases and has failed to adopt meaningful domestic measures or join the international effort to reduce greenhouse gas emissions. The Inter-American Commission on Human Rights initially denied the petition, then changed course and announced it would hold hearings on the suit.