by W. Eschenbach, March 15, 2021 in WUWT
Clouds are said to be the largest uncertainty in climate models, and I can believe that. Their representation in the models is highly parameterized, each model uses different parameters as well as different values for the same parameters, and so of course, different models give very different results. Or to quote from the IPCC, the Intergovernmental Panel on Climate Change:
In many climate models, details in the representation of clouds can substantially affect the model estimates of cloud feedback and climate sensitivity. Moreover, the spread of climate sensitivity estimates among current models arises primarily from inter-model differences in cloud feedbacks. Therefore, cloud feedbacks remain the largest source of uncertainty in climate sensitivity estimates.
The question of importance is this—if the earth heats up, will clouds exacerbate the warming or will they act to reduce the warming? The general claim from mainstream climate scientists and the IPCC is that the clouds will increase the warming, viz:
All global models continue to produce a near-zero to moderately strong positive net cloud feedback.
My own theory is that clouds and other emergent climate phenomena generally act to oppose any increases in surface temperature. So me, I’d expect the opposite of what the models show. I figured that there should be a negative cloud feedback that opposes the warming.
So I thought I’d take a look at answering the question using the CERES satellite dataset. As a prologue, here’s a short exposition about measuring the effect of clouds.