The new DOE climate report
Posted on 6 August 2025 by Ken Rice
This is a re-post from and Then There's Physics
Since ClimateballTM (H/T Willard) is back with the publication of the first report from the US Department of Energy’s (DOE) Climate Working Group, I thought it was time to start writing posts again. The report is called A Critical Review of Impacts of Greenhouse Gas Emissions on the U.S. Climate, and the authors are John Christy, Judith Curry, Steven Koonin, Ross McKitrick, and Roy Spencer.
The first point to make is that if someone had asked me 10 years ago to guess the names of a group of scientists who might be recruited to write a contrarian report on climate science, I would have guessed a significant number of those listed above. Why are there so few contrarians that it’s pretty easy to guess most who might be invited to write such a report? Why are there no new names? Why were no early-career researchers invited? The answer is pretty obvious: the bench is pretty thin.
The report is rather long, so I’ve only read the Executive Summary and the chapter on Climate Sensitivity, since I’ve written quite a lot about that. The Executive Summary would do reasonably well in ClimateBall Bingo and the climate sensitivity chapter mostly complained about climate models and promoted what they refer to as data-driven estimates of climate sensitivity, such as those presented by Nic Lewis. These are perfectly valid ways of estimating climate sensitivity, but they tend to return lower values than some other methods and there are reasons to be cautious of accepting these as being somehow more reliable than other estimates.
So, there’s nothing particularly original about the chapter on climate sensitivity. Pretty much what you’d expect from this group of authors. It does, however, give me an opportunity to highlight a few things that I think are pretty important and which seem to be ignored by this report.
One key aspect of this issue is that carbon dioxide (CO2) accumulates in the atmosphere. In other words, while humans continue to emit CO2 into the atmosphere, atmospheric CO2 concentrations will continue to increase. There is also now strong evidence to indicate that warming will also continue until CO2 emissions get to (net) zero and that the overall warming depends linearly on cumulative CO2 emissions. In other words, if we emit twice as much, we warm twice as much.
So, whatever range of climate sensitivity you think is most likely, if you accept that there is a level of warming we might want to try to avoid, then anthropogenic/human emissions of CO2 need to get to (net) zero. How rapidly we’d need to do so does depend on climate sensitivity, but that we’d need to do so does not.
Interestingly. the report does suggest that estimates for the transient climate response (TCR) tend to show more agreement than those for the equilibrium climate sensitivity (ECS). This might suggest that there should be more agreement about how rapidly we should be aiming to reduce emissions, even if there isn’t agreement about how we might achieve this. Of course, that there isn’t is not a great surprise.
I suspect there will be many other more detailed response to this DOE report. Will try to highlight any others I find in the comments.
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