Recent cloud controlling factor analyses indicate higher climate sensitivity

Wilson Kemsley, Sarah, Nowack, Peer and Ceppi, Paulo (2026) Recent cloud controlling factor analyses indicate higher climate sensitivity. Geophysical Research Letters. ISSN 0094-8276

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Abstract

Cloud feedback is a dominant source of uncertainty in climate model estimates of equilibrium climate sensitivity (ECS). Cloud controlling factor analysis can observationally constrain cloud feedback. For the first time, we use separate rather than unified frameworks to assess high- and low-cloud feedbacks and constrain the net cloud feedback and subsequently, the ECS. We find a robustly positive cloud feedback (i.e., a negative feedback is < 0.5% probable), indicating that clouds amplify global warming. We assess the individual and combined impacts of our cloud feedback constraints on ECS using three approaches. Two indicate an upward ECS shift with reduced uncertainty, preserving ECS–feedback correlations but using cloud feedback as a single line of evidence. The third, a Bayesian framework combining multiple lines of evidence, also suggests a higher ECS but with a smaller increase and broader confidence range.

Item Type:	Article
Additional Information:	Data Availability Statement: All data used in this research is freely available. ERA5 meteorological reanalysis data are from the Copernicus Climate Change Service (Hersbach et al., 2023a, 2023b). Combined MODIS Aqua–Terra data are freely available and downloaded with monthly resolution (NASA, 2022). CMIP5/6 data are obtained from the UK Center for Environmental Data Analysis portal (CEDA). Cloud radiative kernels are freely available at Zelinka (2022), and cloud-radiative sensitivities were calculated using code adapted from Nowack (2021). We used ECS values from Zelinka (2024). Code for reproducing Sherwood et al. (2020)'s Bayesian analysis was taken from Webb (2022).
Uncontrolled Keywords:	climate sensitivity,cloud feedback
Faculty \ School:	Faculty of Science > School of Environmental Sciences University of East Anglia Research Groups/Centres > Theme - ClimateUEA
UEA Research Groups:	Faculty of Science > Research Groups > Centre for Ocean and Atmospheric Sciences Faculty of Science > Research Groups > Climatic Research Unit
Depositing User:	LivePure Connector
Date Deposited:	19 Mar 2026 16:30
Last Modified:	19 Mar 2026 20:30
URI:	https://ueaeprints.uea.ac.uk/id/eprint/102503
DOI:	10.1029/2025GL118366

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