There is No Scientific Justification to Revoke the Endangerment Finding

The following is a statement by Katharine Hayhoe, The Nature Conservancy’s chief scientist, in response to the United States Environmental Protection Agency’s decision on February 12 to repeal the Endangerment Finding. The finding—a scientific and legal determination that greenhouse gases endanger public health and welfare—allows the government to regulate emissions of carbon dioxide and other greenhouse gases under the Clean Air Act.

“Since the United States Environmental Protection Agency issued its Endangerment Finding in 2009, the scientific evidence connecting greenhouse gas emissions to health impacts from climate change has only grown stronger. The foundation of that finding has been repeatedly tested and remains robust, while scientific understanding of how rising heat-trapping gases harm human health and well-being continues to expand and deepen.

Over the past two decades, I’ve contributed to this body of research myself—quantifying the risks posed by rising CO₂ levels to people, infrastructure and the natural systems we depend on, and authoring multiple U.S. National Climate Assessments. These authoritative and exhaustive reports helped build the scientific foundation that underpins the Endangerment Finding, and their conclusions weren’t based on ideology. They were rooted in rigorous, peer‑reviewed evidence; evidence that has only become clearer with time.

For more than a decade, the Endangerment Finding has enabled the EPA to limit greenhouse gas pollution and allowed other federal agencies to put safeguards in place that protect people’s health. Reversing it wouldn’t change the science—it would only make it harder to mitigate the risks we’re already facing, from extreme heat to flooding and increasingly severe wildfires.

There is also a practical reality. When foundational climate policies are repeatedly questioned, reversed or tied up in legal uncertainty, it becomes harder for families, businesses and local governments to plan for the future. Stability matters. Predictability matters. Maintaining science‑based policies isn’t just prudent—it’s the reliable foundation we need to build a safer, healthier and more resilient nation.”