Abstract We present an assessment of the impacts on atmospheric composition and radiative forcing of short‐lived pollutants following a worldwide decrease in anthropogenic activity and emissions comparable to what has occurred in response to the COVID‐19 pandemic, using the global composition‐climate model United Kingdom Chemistry and Aerosols Model (UKCA). Emission changes reduce tropospheric hydroxyl radical and ozone burdens, increasing methane lifetime. Reduced SO2 emissions and oxidizing capacity lead to a decrease in sulfate aerosol and increase in aerosol size, with accompanying reductions to cloud droplet concentration. However, large reductions in black carbon emissions increase aerosol albedo. Overall, the changes in ozone and aerosol direct effects (neglecting aerosol‐cloud interactions which were statistically insignificant but whose response warrants future investigation) yield a radiative forcing of −33 to −78 mWm−2. Upon cessation of emission reductions, the short‐lived climate forcers rapidly return to pre‐COVID levels; meaning, these changes are unlikely to have lasting impacts on climate assuming emissions return to pre‐intervention levels.

中文翻译：

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与 COVID-19 大流行相关的排放减少后，短期气候驱动因素对气候的影响最小


摘要：我们使用全球成分-气候模型，评估了全球范围内人类活动和排放量的减少（与应对 COVID-19 大流行的情况相当）后，短期污染物对大气成分和辐射强迫的影响。王国化学和气溶胶模型（UKCA）。排放变化减少了对流层羟基自由基和臭氧负担，增加了甲烷寿命。 SO2 排放量和氧化能力的减少导致硫酸盐气溶胶减少和气溶胶尺寸增加，同时云滴浓度降低。然而，黑碳排放量的大幅减少会增加气溶胶反照率。总体而言，臭氧和气溶胶直接影响的变化（忽略统计上不显着的气溶胶-云相互作用，但其响应值得未来研究）产生-33至-78 mWm−2的辐射强迫。一旦停止减排，短暂的气候驱动力就会迅速恢复到新冠疫情之前的水平；也就是说，假设排放量恢复到干预前的水平，这些变化不太可能对气候产生持久影响。