气候变化影响适应和脆弱性评估报告进展:IPCC AR5到AR6的新认知

Understandings of assessment reports on climate change impacts,adaptation and vulnerability:progress from IPCC AR5 to AR6

IPCC第六次评估报告第二工作组(IPCC AR6 WGⅡ)重点关注气候变化的影响、风险、适应性和脆弱性。报告以最新的数据、翔实的证据、多元的方法定量评估了气候变化对自然和人类系统的影响。相比于AR5,AR6 WGⅡ取得了以下进展:1)内容上明确了气候变化的影响归因于人为气候强迫、非气候因子作用和天气敏感性识别等三类;气候变化带来的127个关键风险将变得广泛、普遍或不可逆转,将全球变暖限制在1.5℃,可大大减少气候变化对自然和人类系统的损失和破坏,指出来适应转型的重要性;2)在评估方法上,AR6采用了最新的SSPs和RCPs组合的SSPs情景,综合性更强;3)AR6对风险和解决方案的关注有所增加,并在AR5的基础上明确了5个“关注理由(RFCs)”的关键风险面临的风险水平将在较低的全球变暖水平上变为高到极高;4)AR6明确了气候行动的紧迫性,将适应和减缓相结合以支持气候恢复力(CRD)发展,指出了立即行动以应对气候风险的重要性和紧迫性。

The second working group of the IPCC Sixth Assessment Report(IPCC AR6 WGⅡ)focuses on the impact,risk,adaptation and vulnerability of climate change.The report quantitatively assesses the impact of climate change on natural and human systems with the latest data,detailed evidence and diverse methods.Compared to AR5,the following progress has been made:Firstly,The content clarifies that the impact of climate change is attributable to three categories:anthropogenic climate forcing,non-climate factor action and weather sensitivity identification,127 key risks from climate change will become widespread or irreversible,and limiting global warming to 1.5℃can greatly reduce climate change loss and damage to natural and human systems,pointing to the importance of adapting to transition.Secondly,AR6 WGⅡadopts the latest combination of SSPs and RCPS in terms of evaluation method,which is more comprehensive.Thirdly,AR6 WGⅡhas focus on risks and solutions,and on the basis of AR5 WGⅡ,it is clarified that under different future warming scenarios,the risk level of the key risks facing the five“reasons for concern(RFCs)”will be relied on lower to very high levels of global warming.Finally,AR6 WGⅡclarifies the urgency of climate action,combining adaptation and mitigation to support sustainable development is essential for climate resilience development pathways,pointing to the importance of immediate action to address climate risks.