IPCC AR6报告解读:气候系统对太阳辐射干预响应

Climate system response to solar radiation modification

IPCC第六次评估报告(AR6)第一工作组报告评估了太阳辐射干预(Solar radiation modification,SRM)对气候系统和碳循环的影响。在大幅度减排基础上,太阳辐射干预有潜力作为应对气候变化的备用措施。目前,对于太阳辐射干预气候影响的评估都是基于模式模拟结果。评估主要结论如下:太阳辐射干预可以在全球和区域尺度上抵消一部分温室气体增加造成的气候变化(高信度);但是太阳辐射干预无法在全球和区域尺度上完全抵消温室气体增加引起的气候变化(几乎确定);有可能通过适当的太阳辐射干预设计,同时实现多个温度变化减缓目标(中等信度);在高强度温室气体排放情景下,如果太阳辐射干预实施后突然终止,并且这种终止长时间持续,将会造成快速的气候变化(高信度);如果在减排和CO_(2)移除的情况下,太阳辐射干预的实施强度逐渐减小至零,将显著降低太阳辐射干预突然终止产生的快速气候变化风险(中等信度);太阳辐射干预会通过降温作用,促进陆地和海洋对大气CO_(2)的吸收(中等信度),但是太阳辐射干预无法缓解海洋酸化(高信度);太阳辐射干预对其他生物化学循环影响的不确定性大。由于对云-气溶胶-辐射过程的相互作用和微物理过程认知有限,目前对平流层气溶胶注入、海洋低云亮化、高层卷云变薄等太阳辐射干预方法的冷却潜力和气候效应的认知还有很大的不确定性。

The IPCC recently released the Sixth Assessment Report(AR6).The Working Group I contribution to the AR6“Climate change 2021:the physical science basis”addresses the most up-to-date physical understanding of the climate system and climate change.Climate system and the carbon cycle response to solar radiation modification(SRM)is assessed in this report.SRM can be considered as a potential supplement to deep emission reduction to counteract anthropogenic climate change.All assessment of climate effect from SRM are from modeling work.Key AR6 assessment relevant to SRM are:SRM could offset some of the effects from increasing greenhouse gases on global and regional climate(high confidence),but there would be substantial residual or overcompensating climate change at the regional scales and seasonal time scales(virtually certain).It is possible to stabilize multiple large-scale temperature indicators simultaneously by tailoring the deployment strategy of SRM options(medium confidence).A sudden and sustained termination of SRM in a high greenhouse gas emissions scenario would cause rapid climate change(high confidence),but a gradual phase out of SRM combined with emissions reductions and carbon dioxide removal would avoid large rates of changes(medium confidence).The cooling caused by SRM would increase the global land and ocean CO_(2) sinks(medium confidence),but SRM would not mitigate ocean acidification(high confidence).Our understanding of climate response to aerosol-based SRM options including stratospheric aerosol injection,marine cloud brightening,and cirrus cloud thinning is limited due to large uncertainties associated with aerosol–cloud–radiation interactions.