Sea-surface temperature pattern effects have slowed global warming and biased warming-based constraints on climate sensitivity

作者：Kyle C. Armour, Cristian Proistosescu, Yue Dong, Lily Caroline Hahn, Edward Blanchard‐Wrigglesworth, Andrew George Pauling, Robert C. J. Wills, Timothy Andrews, Malte Fabian Stuecker, Stephen Po–Chedley, Ivan Mitevski, Piers M. de F. Forster, Jonathan M. Gregory · 发表于：Proceedings of the National Academy of Sciences · 年份：2024 · DOI：10.1073/pnas.2312093121 · 被引用次数：79 · 研究领域：Climate variability and models、Oceanographic and Atmospheric Processes、Meteorological Phenomena and Simulations

The observed rate of global warming since the 1970s has been proposed as a strong constraint on equilibrium climate sensitivity (ECS) and transient climate response (TCR)-key metrics of the global climate response to greenhouse-gas forcing. Using CMIP5/6 models, we show that the inter-model relationship between warming and these climate sensitivity metrics (the basis for the constraint) arises from a similarity in transient and equilibrium warming patterns within the models, producing an effective climate sensitivity (EffCS) governing recent warming that is comparable to the value of ECS governing long-term warming under CO[Formula: see text] forcing. However, CMIP5/6 historical simulations do not reproduce observed warming patterns. When driven by observed patterns, even high ECS models produce low EffCS values consistent with the observed global warming rate. The inability of CMIP5/6 models to reproduce observed warming patterns thus results in a bias in the modeled relationship between recent global warming and climate sensitivity. Correcting for this bias means that observed warming is consistent with wide ranges of ECS and TCR extending to higher values than previously recognized. These findings are corroborated by energy balance model simulations and coupled model (CESM1-CAM5) simulations that better replicate observed patterns via tropospheric wind nudging or Antarctic meltwater fluxes. Because CMIP5/6 models fail to simulate observed warming patterns, proposed warming...