The Congressional Research Service issued a report July 23 finding that courts still need to a number of pressing legal and liability issues surrounding climate change and greenhouse gas impacts. Though the U.S. Supreme Court has twice ruled the Environmental Protection Agency has the authority to regulate greenhouse gases under the Clean Air Act, the service said that outstanding issues regarding water shortages, sea levels rise, and other climate impacts persist. The report, Climate Change and Existing Law: A Survey of Legal Issues Past, Present, and Future, also found that the courts need to address the role of the National Environmental Policy Act and Endangered Species Act in addressing climate impacts.