Assessment of Equilibrium Climate Sensitivity of the Community Earth System Model Version 2 Through Simulation of the Last Glacial Maximum
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- Jiang Zhu
- Climate and Global Dynamics Laboratory National Center for Atmospheric Research Boulder CO USA
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- Bette L. Otto‐Bliesner
- Climate and Global Dynamics Laboratory National Center for Atmospheric Research Boulder CO USA
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- Esther C. Brady
- Climate and Global Dynamics Laboratory National Center for Atmospheric Research Boulder CO USA
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- Christopher J. Poulsen
- Department of Earth and Environmental Sciences University of Michigan Ann Arbor MI USA
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- Jessica E. Tierney
- Department of Geosciences the University of Arizona Tucson AZ USA
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- Marcus Lofverstrom
- Department of Geosciences the University of Arizona Tucson AZ USA
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- Pedro DiNezio
- Department of Atmospheric and Oceanic Sciences University of Colorado Boulder Boulder CO USA
説明
<jats:title>Abstract</jats:title><jats:p>The upper end of the equilibrium climate sensitivity (ECS) has increased substantially in the latest Coupled Model Intercomparison Projects phase 6 with eight models (as of this writing) reporting an ECS > 5°C. The Community Earth System Model version 2 (CESM2) is one such high‐ECS model. Here we perform paleoclimate simulations of the Last Glacial Maximum (LGM) using CESM2 to examine whether its high ECS is realistic. We find that the simulated LGM global mean temperature decrease exceeds 11°C, greater than both the cooling estimated from proxies and simulated by an earlier model version (CESM1). The large LGM cooling in CESM2 is attributed to a strong shortwave cloud feedback in the newest atmosphere model. Our results indicate that the high ECS of CESM2 is incompatible with LGM constraints and that the projected future warming in CESM2, and models with a similarly high ECS, is thus likely too large.</jats:p>
収録刊行物
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- Geophysical Research Letters
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Geophysical Research Letters 48 (3), 2021-02-02
American Geophysical Union (AGU)
