Sniff Test for Claims of Negative Feedbacks
Cloud Feedbacks are Likely Positive, from Ceppi et al 2026 In my last post I shared what I consider a pretty good "sniff test" for claims that sensitivity is so low that global warming from human fossil fuel emissions can't cause any significant global warming. I showed that low sensitivity claims require the existence of large external forcings that simply can't be found in nature. Today it occurred to me that there's another "sniff test" we can use when people claims that climate feedbacks are very small or negative. Let's begin quantifying feedbacks - that is, energy that gets looped back into the system to either amplify or dampen a warming signal. Total feedbacks ( λt ) is the sum of all individual feedbacks which have been quantified in various studies. Here is an accounting of the dominant feedbacks in the climate system: Water Vapor (λwv): 1.80 W/m²/°C Lapse Rate (λlr): -0.50 W/m²/°C Surface Albedo (λsa): 0.35 W/m²/°C Clouds (λcl): 0.43 W/m...