The DOE Scientific Report Underpinning the EPA’s Decision to Reconsider the 2009 Endangerment Finding on CO2

A Note to Journalists: Please take few minutes to read some of this so that maybe you can skip asking me for an interview.

Around 3 p.m. ET today, 29 July 2025, a Department of Energy report entitled “A Critical Review of Impacts of Greenhouse Gas Emissions on the U.S. Climate” will be made available here. This is the report providing the scientific basis for today’s announced decision by EPA Administrator Lee Zeldin to reconsider the 2009 CO2 Endangerment Finding.

The report has 5 authors: John Christy, Judith Curry, Steve Koonin, Ross McKitrick, and myself.

We were asked by DOE Secretary Wright a few months ago to produce this report. As the first few pages of the report will explain, we had no pressure to come to any conclusions; we asked for complete autonomy.

Also, we had no knowledge through the whole process of what the decision-makers at the EPA were going to do regarding energy policy. We suspected the Endangerment Finding would be the topic of greatest interest, but we also knew that the EPA’s strategy for rescinding that could take a mostly legal approach, with little need for science arguments… for now.

Even today, I have no idea how much recent court rulings vs. updated (and less biased) science figured into the EPA’s decision.

Why a DOE Report to Support an EPA Decision?

My understanding is that the Trump Administration and all of its Executive Branch agencies have been very busy on myriad issues. Only one of the executive-level appointees in the Administration had the background knowledge and interest to invest in making this science report happen: Energy Secretary Chris Wright. I suspect (this is my reading between the lines) that it was agreed between the White House, EPA, and DOE that Sec. Wright would take the lead on the science document.

Chris called me at home and asked me if I would participate, and he asked who I would recommend for other authors of the report. He had been following my research for many years. He also had on his list of potential contributors the others who now appear on the report with me.

During preparation of the report we decided to avoid any engagement with the press on what we were doing. It would have only been a distraction, and we had little time to accomplish what the Obama Administration spent years and millions of dollars to produce as the original Technical Support Document (TSD) for the 2009 Endangerment Finding.

Our report has 141 pages, 350 references (most if not all peer-reviewed), 6.6% of which were studies we authored or co-authored. The report could not address every claim made in the 2009 Endangerment Finding’s Technical Support Document. Instead, we focused on some of the central claims, the science underpinning them, and especially on the National Climate Assessments, especially NCA4 and NCA5 (the latest), which are relied upon by the U.S. Congress to assist in the making of laws and apportioning research funds.

One thing I learned through this process is how prolific and smart a researcher Ross McKitrick (U. of Guelph, Ontario) is. He was indispensable to our effort. But everyone brought their own experiences and opinions to the process, and we often had disagreements… but none that could not be quickly resolved.

Another thing I learned was just how poorly the science of climate change has been communicated to the public. For example, if you follow Roger Pielke, Jr’s research you will know that most of what the public has been told about climate change and severe weather has been a lie — and Roger still considers human climate change to be an issue worth addressing. It’s just not a “crisis”, and nothing we see in severe weather has been tied to human greenhouse gas emissions.

And that’s not a skeptical talking point, it’s according to the IPCC (!)

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