Ashley Siefert Nunes
WASHINGTON (September 16, 2025)—The Union of Concerned Scientists (UCS) today submitted a letter with more than 1,000 signatory scientists and experts, objecting to the U.S. Environmental Protection Agency’s (EPA) proposal to rescind the 2009 Endangerment Finding. The letter—featuring signatories from nearly every state and the District of Columbia—was released publicly and delivered to EPA via the official comment docket.
The landmark Endangerment Finding affirmed that heat-trapping emissions driving climate change endanger the public. It also firmly established EPA’s obligation, under the Clean Air Act, to regulate greenhouse gas emissions from vehicles, power plants, oil and gas operations, and other sources of these pollutants.
“As climate scientists, public health experts, and economists, we can attest to the indisputable scientific evidence of human-caused climate change, its harmful impacts on people's health and well-being, and the devastating costs it is imposing on communities across the nation and around the world,” states the letter. “This explicit attempt to undermine or weaken these findings, as well as the critical regulations linked to them, is contrary to science and the public interest.”
The letter also rebukes a sham report commissioned by U.S. Department of Energy Secretary Chris Wright and drafted in secret by five known climate contrarians that is being used as a basis for this attempt to overturn the Endangerment Finding.
“[The DOE report] is rife with inaccuracies, deliberately cherry-picks and mischaracterizes data, and has not undergone a rigorous scientific review process. The scientific evidence on human-caused climate change and its consequences was unequivocal in 2009 and, since that time, has become even more dire and compelling.”
Instead, the letter writers urge EPA to consider the best available science, including the U.S. Fifth National Climate Assessment, the Intergovernmental Panel on Climate Change Sixth Assessment Report, and the 2024 Lancet Countdown Report on Climate and Health—assessments backed by thousands of independent, peer-reviewed scientific studies rigorously conducted by scientists in the United States and around the world.
The letter concludes by stating: “We urge you to stop dismantling critical climate regulations and evading the EPA’s responsibility by pushing disinformation about climate science and impacts. Instead, we call on you to act with urgency to help address this pressing challenge by limiting heat-trapping emissions. People across the nation are relying on the EPA to fulfill its mission to protect public health and the environment.”