关于复合型极端事件的新认识和启示

近年来，极端天气气候事件频繁发生，且常常表现为多种事件交织形成的复合型极端事件。为了更好地认识复合型极端事件，IPCC AR6基于现有的新证据评估了复合型极端事件的最新研究成果，并取得一些新认识：扩展了有关复合型极端事件的定义，重点围绕高温干旱复合型极端事件、复合洪水和野火，评估了复合型极端事件的变化特征，探讨了复合型极端事件多因子之间的依赖性，对人类活动的影响进行了归因分析并给出了未来可能的变化。这些评估结果丰富了对复合型极端事件的基本认识。但根据现有的评估可以发现，目前在复合型极端事件发生发展机理认识方面还存在不足；同时，未来仍需进一步完善跨学科跨部门跨区域研究，加强对复合型极端事件形成机理、预估及其对生态系统，经济社会影响风险的评估，提高对区域气候变化的适应能力。

Advances in scientific understanding on compound extreme events

In recent years, extreme weather and climate events have occurred frequently, and are often compound extreme events formed by the interweaving of a variety of events.They have attracted extensive attention and research due to their serious hazards.In order to better understand compound extreme events, IPCC AR6 evaluated the latest research results of compound extreme events based on existing new evidence, and obtained some new understandings.The definition of compound extreme events is expanded.Focusing on heatwave and drought compound extreme events, compound floods and wildfires, the variation characteristics of compound extreme events are evaluated, the dependence among multiple factors of compound extreme events is discussed, the attribution analysis of the impact of human activities is carried out, and the possible projection in the future is given.These assessment results have enriched the current basic understanding of compound extreme events.However, according to the existing assessment, it can be seen that there are still insufficient understandings of the mechanism of occurrence and development of compound extreme events.At the same time, it is still necessary to further improve cross-disciplinary, cross-departmental and cross-regional research, strengthen the assessment of formation mechanism and projection of compound extreme events and their impact and risk on ecosystem, economy and society, and improve the adaptability to regional climate change in the future.