Clarke has supported efforts to combat climate change and limit fossil fuel consumption. She has generally opposed legislation that gives priority to economic over conservation interests, such as the Stop the War on Coal Act of 2012 and the Conservation and Economic Growth Act of 2012. She has supported legislation that increases conservation efforts and regulation of the energy industry, such as the Offshore Drilling Regulations and Other Energy Law Amendments Act of 2010. Clarke received 100 percent ratings from Environment America, the League of Conservation Voters, and the Sierra Club, the latter on her clean water positions, in 2011 while she received a low rating of 14% over the period 2008–11 from the Global Exchange for her loyalty to the finance, insurance, and real estate lobbies. She was strongly critical of the Trump administration's decision to withdraw from the Paris Agreement.