The Environmental Protection Agency has revoked a key scientific finding that supported U.S. regulations on greenhouse gas emissions. This decision rescinds a 2009 declaration that carbon dioxide and other gases endanger public health. EPA Administrator Lee Zeldin announced the move Thursday, calling it a major deregulatory action. Critics argue it undermines efforts to combat climate change and could lead to more pollution. Environmental groups are certain to challenge the action in court. The EPA also proposes delaying a Biden-era rule on vehicle emissions, which could impact the push for electric vehicles.

Climate change is often viewed as an issue that’s too big for individual action to matter. But calculations show that when personal choices ad…