IPCC AR6报告解读:气候系统对二氧化碳移除响应

Climate system response to carbon dioxide removal

IPCC AR6报告中控温1.5℃和2℃的低排放情景需要在21世纪中叶以后实现净负CO_(2)排放,这需要在很大程度上依赖CO_(2)移除措施。AR6对CO_(2)移除的主要评估结论如下:CO_(2)移除有潜力从大气中去除CO_(2)(高信度);如果CO_(2)移除量超过CO_(2)排放量,将实现净负CO_(2)排放,降低大气CO_(2)浓度,减缓海洋酸化(高信度);通过CO_(2)移除方法从大气中去除的CO_(2)会部分被海洋和陆地释放的CO_(2)抵消(非常高信度);如果净负CO_(2)排放可以实现并且持续,CO_(2)引起的全球升温趋势将会逐渐扭转,但是气候系统的其他变化(例如海平面升高)仍会在未来的几十年到千年尺度上持续(高信度);不同CO_(2)移除方法会对生物化学循环和气候产生广泛的影响,这些影响会加强或减弱CO_(2)移除的降温潜力,并且影响水资源、食物生产和生物多样性(高信度)。

The IPCC recently released the Six Assessment Report(AR6),addressing the most up-to-date physical understanding of the climate system and climate change.Climate system and the carbon cycle response to carbon dioxide removal is assessed in this report.Carbon dioxide removal(CDR)is a necessary component of the IPCC low emissions scenarios of SSP1-1.9 and SSP1-2.6 that keeps global warming from preventing 1.5℃or 2.0℃.AR6 key assessment relevant to CDR are:CDR has the potential to removal CO_(2) from the atmosphere and durably store it in reservoirs(high confidence);If the amount of CO_(2) removed from the atmosphere exceeds anthropogenic CO_(2) emission,CDR would lead to net negative emissions,lowering atmospheric CO_(2) concentration and reversing surface ocean acidification(high confidence);CO_(2) sequestered from the atmosphere by CDR would be partially compensated by CO_(2) release from land and ocean carbon stores(very high confidence);If global net negative CO_(2) emissions were to be achieved and be sustained,the global CO_(2)-induced surface temperature increase would be gradually reversed but other climate changes(such as sea level rise)would continue in their current direction for decades to millennia(high confidence).CDR methods can have potentially wide-ranging effects on biogeochemical cycles and climate,which can either weaken or strengthen the potential of these methods to remove CO_(2) and reduce warming,and can also influence water availability and quality,food production and biodiversity(high confidence).