Wood Romances

Along with the publication of Emily Judd's reconstruction[1] of global temperatures, she and her team compiled an up-to-date reconstruction of CO2 concentrations from proxy data. I shared in a previous post how this new reconstructions shows a CO2 and GMST as well-correlated on geologic time scales, with GMST increasing by ~8 C for 2xCO2. Her CO2 reconstruction is another step forward for paleoclimate because it makes use of a growing database of proxy evidence, much of which is being compiled at the Paleo CO2 project . For the Paleozoic and Mesozoic, Judd's reconstruction followed Foster et al 2017 [2] pretty closely, especially during the Paleozoic, but she also included additional data from Witkowski et al 2018[4][3]. Differences between Judd's and Foster's reconstruction had to do with different ways of site and time averaging and updates from Witkowski's study. During the Cenozoic, she followed more recent work by Rae et al 2021 [5] which agrees closely with t...

In a recent talk  (relevant excerpt  here ) given to an Australian political group called the Institute for Public Affairs (IPA), William Happer argued that doubling CO2 causes only 0.71 K warming, and that amount of warming for 2xCO2 is too small to matter. He then suggests that in order to make CO2 a problem, scientists had to invent giant feedbacks to amplify warming by as much as 10x the amount caused by CO2 alone. I've seen this claim repeated by others on X and other social media platforms, but as best I can tell Happer originates this particular argument. So I'd like to consider, is this plausible at all? I think it's pretty easy to investigate this and show conclusively that it is not. In fact, even Happer disagreed with this claim as recently as 2020. Happer's Argument At about the 1 minute mark of the above linked excerpt, Happer explains his math on how he arrives at 0.71 K for equilibrium climate sensitivity (ECS). He begins with the equation: F = εσT^4, whe...

In January, I blogged about a lecture I watched from Jessica Tierney, a geologist who has done some fascinating work in paleoclimate, in which she described the research behind a new paper that was at the time still undergoing peer review. You can watch the video and see my previous thoughts about this here . Ever since I watched this lecture, I have been anticipating the publication of the paper and hoping that the text wouldn't be behind a pay wall so I could learn more about what Tierney shared in her lecture. Well, late last week, both of my hopes became a reality. The paper is published and the full version is available. The lead author is Emily Judd[1], and this appears to be a remarkable paper. The tl;dr for this paper is that Emily Judd and her colleagues put together a data analysis (PhanDA) reconstruction of global temperatures and CO2 for the last 485 million years (most of the Phanerozoic), and they found that GMST varied greatly on geologic time scales, ranging from ...

A recent paper[1] published in the MDPI journal Climate by Frank Stefani provides a wonderful illustration of why we should never treat papers from MDPI journals as having any competent, let alone robust peer review. This paper argues that TCR = 1.1°C (0.6°C - 1.6°C) for doubling CO2. I'm not going to evaluate the entire paper here, since that would take too much time. The paper does make some counterfactual claims, like there's a "nearly perfect correlation of solar activity with temperatures over about 150 years." That's objectively false, but the correlation between CO2 forcings and GMST has an r^2 = 0.88. There's also some comical contrarian alarmism in this paper: "we fear that the huge Milankovitch drivers will—perhaps much too soon—massively interfere with the solar and anthropogenic factors that were considered in this paper." There's a lot we could say about this paper, but I want to focus here on some elementary math errors that would ...