美国迈阿密大学 Haozhe He 的团队近日在研究二氧化碳作用力的状态依赖性及其对气候敏感性的影响中取得新进展。该项研究成果发表在2023年12月1日出版的《科学》上。

研究人员表明 IRF_2×CO2 不是常数，而是取决于气候基本状态，CO₂ 每增加一倍，IRF_2×CO2 增加约 25 %，自前工业化时代以来，主要由于平流层上部的冷却，IRF_2×CO2 增加了约 10 %，这意味着气候敏感性按比例增加。这种基态依赖性也解释了 IRF_2×CO2 中约一半的模式间扩散问题，这一问题在气候模型中持续争论了近 30 年。

据悉，在评估二氧化碳(CO₂)变化对地球气候的影响时，人们普遍认为，给定 CO₂ 浓度加倍(IRF_2×CO2)，所产生的瞬时辐射作用力是恒定的，气候敏感性的变化来自辐射反馈的差异或这些反馈对气候基本状态的依赖。

附：英文原文

Title: State dependence of CO₂ forcing and its implications for climate sensitivity

Author: Haozhe He, Ryan J. Kramer, Brian J. Soden, Nadir Jeevanjee

Issue&Volume: 2023-12-01

Abstract: When evaluating the effect of carbon dioxide (CO₂) changes on Earth’s climate, it is widely assumed that instantaneous radiative forcing from a doubling of a given CO₂ concentration (IRF_2×CO2) is constant and that variances in climate sensitivity arise from differences in radiative feedbacks or dependence of these feedbacks on the climatological base state. Here, we show that the IRF_2×CO2 is not constant, but rather depends on the climatological base state, increasing by about 25% for every doubling of CO₂, and has increased by about 10% since the preindustrial era primarily due to the cooling within the upper stratosphere, implying a proportionate increase in climate sensitivity. This base-state dependence also explains about half of the intermodel spread in IRF_2×CO2, a problem that has persisted among climate models for nearly three decades.

DOI: abq6872

Source: https://www.science.org/doi/10.1126/science.abq6872