biostudies-literatureDe BColumbia UniversityNational Aeronautics and Space AdministrationNational Science Foundation of Sri LankaNational Science Foundatione1073https://www.ebi.ac.uk/biostudies/studies/S-EPMC9285496biostudies-literatureUnknown23(3)The persistent inter-model spread in the response of global-mean surface temperature to increased CO₂ (known as the "Equilibrium Climate Sensitivity," or "ECS") is a crucial problem across model generations. This work examines the influence of the models' present-day atmospheric circulation climatologies, and the accompanying climatological cloud radiative effects, in explaining that spread. We analyze the Coupled Model Intercomparison Project Phase 6 (CMIP6) models and find that they simulate a more poleward, and thus more realistic, edge of the Hadley cell (HC) in the Southern Hemisphere than the CMIP5 models, although the climatological shortwave cloud radiative effects are similar in the two generations of models. A few CMIP5 models with extreme equatorward biases in the HC Atmospheric science letters : ASLImproved representation of atmospheric dynamics in CMIP6 models removes climate sensitivity dependence on Hadley cell climatological extent.PMC9285496NNH16ZDA001N‐MAP16‐00701914569De BTselioudis GPolvani LMfalseImproved representation of atmospheric dynamics in CMIP6 models removes climate sensitivity dependence on Hadley cell climatological extent.The persistent inter-model spread in the response of global-mean surface temperature to increased CO₂ (known as the "Equilibrium Climate Sensitivity," or "ECS") is a crucial problem across model generations. This work examines the influence of the models' present-day atmospheric circulation climatologies, and the accompanying climatological cloud radiative effects, in explaining that spread. We analyze the Coupled Model Intercomparison Project Phase 6 (CMIP6) models and find that they simulate a more poleward, and thus more realistic, edge of the Hadley cell (HC) in the Southern Hemisphere than the CMIP5 models, although the climatological shortwave cloud radiative effects are similar in the two generations of models. A few CMIP5 models with extreme equatorward biases in the HC 2022-01-01T00:00:00Z2022 Mar2025-04-04T12:43:08.915Z2022-08-05T07:05:00.846ZS-EPMC92854963585993910.1002/asl.1073