Gross Incompetence and Trickery at No Trick Zone
The popular contrarian blog No Trick Zone has made a name for itself for compiling lists of papers that are claimed to demonstrate that some aspect of climate science is all wrong. The papers in these lists generally fall into a few categories:
- Papers published in junk (pay-to-play) or predatory journals.
- Papers published in legitimate journals that don't say what NTZ claims they say.
- Papers published in legitimate journals that do in fact challenge some aspect of AGW.
Studies show that papers in the third category total less than 1% of the recent peer-reviewed literature, so you have to wade through a ton of papers in the first two categories to find the one(s) that belong in the third. It used to be when people promoted these NTZ blogposts on social media, I'd go through the trouble of looking up the papers to confirm that the general principle I describe above still holds true. I no longer waste my time with that (Brandolini's Law and all), but occasionally WUWT picks up on one of these posts, and the incompetence is so apparent that it piques my interest, and I investigate further.
Kenneth Richard on a New Study
A WUWT blogpost today entitled, "New Journal of Climate Study Reduces Doubled CO2 Climate Sensitivity By 40%, To 0.72°C" is one such blogpost. The author, Kenneth Richard, displays what I can only call gross incompetence, and it appears to affect nearly every sentence he writes about the new study. I think it's worth unpacking at least some of these errors so you can see that NTZ (and by extension WUWT) are simply not reliable sources of information about science. In fact, they actively distort science, whether intentionally (deceit) or unintentionally (incompetence), or maybe both.The perturbation to the outgoing infrared radiation from the Earth that would result from 2xCO₂ is 3.7 W/m². The increase in the global mean temperature required to re- equilibrate the Earth's energy balance to this change, considering solely the Earth's blackbody Stefan-Boltzmann response, would be 1.2 °C. A temperature increase of 1.2 °C in response to a forcing of 3.7 W/m² implies a climate sensitivity of 0.32 °C/W/m².There's nothing wrong with this pre-feedback sensitivity estimate, but then Richard quotes the results of a new study[2] looking to quantify the instantaneous radiative forcing (IRF) for 2xCO2. Regarding this study, Richard says:
A new study (Chen et al., 2023) published in Journal of Climate assesses doubling CO2 from 380 to 760 ppm only yields 2.26 W/m², 1.71 W/m², and 0.55 W/m² forcing at the TOA, surface, and troposphere, respectively. These forcing values represent 0.72°C, 0.55°C, and 0.18°C temperature differentials, respectively (0.32°C/W/m²).
The 2.26 W/m² globally averaged TOA forcing identified in this paper is 39% lower than the IPCC’s globally-averaged estimate (3.7 W/m²).
Layers of Incompetence
- ERF is not IRF; IRF is a portion of ERF. ERF is made up of two components, IRF and the sum of all rapid adjustments (RAs), which consists of radiative forcings caused by the atmospheric response to IRF not at the surface. As a general rule of thumb, IRF makes up ~60-70% of ERF[3]. In this paper, IRF makes up 2.26/3.71 = 60.9% of the total ERF of 3.71 W/m^2.
- The common ERF for 2xCO2 estimate is assessed at the tropopause, while Chen's study assesses IRF for 2xCO2 at the top of the atmosphere. CO2 emissions at the q-branch in the stratosphere would thus lower the IRF value with respect to the common assessment of 3.7 W/m^2 at the tropopause.
- This paper did not lower the IPCC's estimate for ERF for 2xCO2. It helps to quantify the IRF at the TOA.
- Richard wrongly assumes that IRF = ERF, but he also equivocates on the value for ERF; he assumes an ERF of 3.7 W/m^2 for 2xCO2 to calculate his 0.32°C/W/m^2 pre-feedback sensitivity value, and then uses that sensitivity value to calculate changes in temperature for 2.26 W/m^2.
- If it were true that IRF = ERF, and if Chen's paper actually did lower ERF from 3.71 to 2.26 W/m^2, that would have the impact of increasing the pre-feedback sensitivity from 1.2/3.71 = 0.32°C/W/m^2 to 1.2/2.26 = 0.53°C/W/m^2, which is unreasonably high.
- In the real world, changes in ERF are affected by feedbacks, and the evidence we have is that overall feedbacks amplify sensitivity from 0.32°C/W/m^2 to ~0.81°C/W/m^2 (corresponding to an ECS of 3°C), largely due to increasing water vapor with warming. There is nothing here that argues for a lower value for sensitivity, and it's not the subject of the paper, which is concerned with IRF; to calculate equilibrium sensitivity, you need both a change in ERF and a corresponding equilibrium change in GMST.
- Richard also doesn't seem to understand that ECS by definition is the equilibrium amount of global surface temperature change that occurs in response to the ERF at the tropopause for doubling CO2 (after accounting for rapid feedbacks).
Conclusion
[2] Chen, Y., Y. Huang, and T. M. Merlis, 2023: The Global Patterns of Instantaneous CO2 Forcing at the Top of the Atmosphere and the Surface. J. Climate, 36, 6331–6347, https://doi.org/10.1175/JCLI-D-22-0708.1.
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