CO2 Coalition Comment #2 on EPA Endangerment Finding
Richard Lindzen
Professor of Earth, Atmospheric, and Planetary Sciences, Emeritus
Massachusetts Institute of Technology
William Happer
Professor of Physics, Emeritus, Princeton University
September 22, 2025
Re: Reconsideration of 2009 Endangerment Finding and Greenhouse Gas Vehicle Standards; Extension of Comment Period (“Proposed Rule”)
U.S. Environmental Protection Agency
Docket ID No. EPA-HQ-OAR-2025-0194
1200 Pennsylvania Avenue NE
Washington, D.C.
Dear Administrator Zeldin,
Thank you for the opportunity to comment on the Environmental Protection Agency’s (“EPA”) Proposed Rule.[1]
We are career physicists with a special expertise in radiation physics, which describes how carbon dioxide and other GHGs affect heat flow in Earth’s atmosphere. We are both members of the National Academy of Sciences. Our CVs are attached.
Our comment focuses on your request for comments as to, “The scientific underpinnings of the Endangerment Finding are weaker than previously believed and contradicted by empirical data, peer-reviewed studies, and scientific developments since 2009 (C-2).”
In our scientific opinion, the scientific underpinnings of the Endangerment Finding (“EF”)[2] are fatally flawed science, for two key reasons.
- It fails to consider contradictory science.
- It is not based on science, it is based on unscientific evidence.
Thus there is no scientific basis for the Endangerment Finding that greenhouse gases (“GHGs”) will endanger the public health and welfare. Furthermore, it endangers the public health and welfare itself.
Accordingly, it should be repealed ASAP.
Scientific details follow.
[1] 90 FR 36288 (Aug. 1, 2025).
[2] EPA, Endangerment and Cause or Contribute Findings for Greenhouse Gases, 74 Fed. Reg. 66,496 (Dec. 15, 2009), Technical Support Document (Dec. 7, 2009)(“TSD”), https://www.epa.gov/sites/default/files/2016-08/documents/endangerment_tsd.pdf
See the complete statement from Richard Lindzen and William Happer here: