Broken climate models.

In short, no scientist who studies the range of scientific literature can reasonably claim that the subject of influences on the climate is remotely ‘settled’. The reality is that a multiplicity of factors are at work, and so, by focusing on human emissions, it appears that the IPCC has, through ‘force fitting’ between its selectively chosen historic global temperature estimates and the inadequately structured and parameterised CMIP^[1] models, reached a highly exaggerated view of climate sensitivity to CO2. Specifically, the range of ECS^[2] values for CO2 adopted by the IPCC overstates those obtained from a physics analysis of causal mechanisms, consistent with satellite measurements, by a factor of up to five to 17 times.^[3]

Dr. Kalveks's article is not for the faint of heart. It is instructive on how non-IPCC analysts arrive at a different understanding of the role of CO2 in determining global temperatures. One paper in particular "attributes 90% of the greenhouse effect to water alone . . . ."^[4]

Kalvek's paper also contains a graph showing how it's the rare computer simulation that comes close to reproducing actual historical measurements of global sea surface temperatures between 1979-2021. He also mentions ad hoc IPCC "tuning" of computer models, an elegant way for those savants to inject a little body English into the process. Whether other computer models incorporate the same thing he doesn't say but it's a good question to ask. Do they? If the medieval warming period can be disappeared, why not goose the effect of CO2? Who could possibly question "the science"?

Notes
^[1] "In climatology, the Coupled Model Intercomparison Project (CMIP) is a collaborative framework designed to improve knowledge of climate change. It was organized in 1995 by the Working Group on Coupled Modelling (WGCM) of the World Climate Research Programme’s (WCRP). It is developed in phases to foster the climate model improvements but also to support national and international assessments of climate change." Wikipedia.
^[2] Equilibrium climate sensitivity. One way to define climate sensitivity that "incorporate[s] the warming from exacerbating feedback loops. . . . Sensitivity to atmospheric CO2 increases is measured in the amount of temperature change for doubling in the atmospheric CO2 concentration." Wikipedia. Now you know.
^[3] "IPCC Climate Models Keep Failing Because They Don’t Respect Physics." By Dr. Rudolph Kalveks, The Daily Skeptic, 11/18/21 (bolding added).
^[4] Coe et al cited in id.