Observational constraints on mixed-phase clouds imply higher climate sensitivity

作者：Ivy Tan, Trude Storelvmo, Mark D. Zelinka · 发表于：Science · 年份：2016 · DOI：10.1126/science.aad5300 · 被引用次数：591 · 研究领域：Atmospheric chemistry and aerosols、Atmospheric aerosols and clouds、Atmospheric and Environmental Gas Dynamics

Global climate model (GCM) estimates of the equilibrium global mean surface temperature response to a doubling of atmospheric CO2, measured by the equilibrium climate sensitivity (ECS), range from 2.0° to 4.6°C. Clouds are among the leading causes of this uncertainty. Here we show that the ECS can be up to 1.3°C higher in simulations where mixed-phase clouds consisting of ice crystals and supercooled liquid droplets are constrained by global satellite observations. The higher ECS estimates are directly linked to a weakened cloud-phase feedback arising from a decreased cloud glaciation rate in a warmer climate. We point out the need for realistic representations of the supercooled liquid fraction in mixed-phase clouds in GCMs, given the sensitivity of the ECS to the cloud-phase feedback.