type: timeline_event
President Trump and EPA Administrator Lee Zeldin announced the repeal of the landmark 2009 Endangerment Finding, which determined that greenhouse gases endanger public health and welfare under the Clean Air Act. Zeldin characterized the action as "the single largest act of deregulation in the history of the United States of America." The finding, originally issued during the Obama administration in response to the 2007 Supreme Court decision Massachusetts v. EPA, provided the legal foundation for federal regulation of carbon dioxide, methane, and other greenhouse gases from vehicles, power plants, and industrial facilities.
The final rule eliminates both the 2009 Endangerment Finding and all subsequent federal greenhouse gas emission standards for vehicles and engines from model years 2012 through 2027 and beyond. The EPA claims the action will save American taxpayers over $1.3 trillion by eliminating what it characterizes as burdensome regulations. White House Press Secretary Karoline Leavitt emphasized the supposed economic benefits during a briefing.
The repeal removes the EPA's statutory authority and obligation to regulate greenhouse gas emissions under the Clean Air Act. Transportation represents the largest source of direct greenhouse gas emissions in the United States, and vehicle emission standards are among the most significant climate regulations affected. The Natural Resources Defense Council immediately announced it would challenge the rule in court, calling it "impossible" for the agency to defend given overwhelming scientific evidence. Former President Obama stated that without the finding, Americans will be "less safe, less healthy and less able to fight climate change, all so the fossil fuel industry can make even more money."
Legal challenges are expected to produce years of litigation potentially reaching the Supreme Court. Climate scientists note that the scientific understanding of human-driven climate change is substantially stronger today than in 2009 when the original finding was issued, providing no factual basis for the reversal. The Sierra Club characterized the action as formalizing "climate denialism as official government policy." Scientists warn the reversal could lead to billions of additional tonnes of greenhouse gas emissions over the next three decades, fundamentally undermining U.S. climate policy and international climate commitments.