Variations of Global Compound Temperature and Precipitation Events and Associated Population Exposure Projected by the CMIP6 Multi-Model Ensemble

Abstract

Compound climate events often pose greater harm to humans and society than single-variable climate issues. This study projects the temporal changes and spatial pattern evolution of four compound climate events (including warm–wet, warm–dry, cold–wet, and cold–dry) and the corresponding population exposure in global land under the shared socioeconomic pathway (SSP) 2–4.5 based on the Coupled Model Intercomparison Project phase 6 simulations. Results show the following: (1) The warm–wet event is significantly decreasing at a rate of 0.06 days per decade, while the cold–wet event is significantly increasing at a rate of 0.06 days per decade. The warm–dry event and cold–dry event show an upward trend but are not significant. (2) All four types of compound events will undergo mutations in the next 80 years, with the warm–dry event having the highest frequency of mutations. (3) West Asia is a high-risk area for warm–dry and cold–wet events. Northern Africa is a hot spot area for the warm–wet event, while Brazil is a hot spot area for the cold–dry event. (4) Areas with exposure levels (population under four compound climate events) of medium or higher are mainly distributed in East Asia, South Asia, and central Africa. When the population exposure exceeds 105 person · day, the area of population exposure to compound events related to dry conditions is greater than that of compound events related to wet conditions. This study has guiding significance for understanding, identifying, analyzing, and preventing compound extreme climate events in the context of global warming.