Increase in compound dry-warm and wet-warm events under global warming in CMIP6 models

Compound dry-warm events (CDWEs) and compound wet-warm events (CWWEs) may lead to detrimental impacts on different sectors of human society such as water supply, agricultural production, and public health. With an increased focus on limiting warming of the global mean temperature to 1.5 °C and 2 °C in climate policy, there is a pressing need to understand changes in these compound events under the two warming levels. In this study, we analyze changes in the frequency of CDWEs and CWWEs in a 1.5 °C and 2 °C warming world based on climate simulations from the Coupled Model Intercomparison Project Phase 6 (CMIP6). Using the 25th/75th and 75th/75th percentile of precipitation and temperature as thresholds to define the two compound events, results show that the global average increase in CDWEs is 105% and 142% from the present period to 1.5 °C warming and 2 °C warming, respectively. For CWWEs, the global average increase is 170% and 260% for 1.5 °C and 2 °C warming, respectively. We further assess changes in the two compound events by the end of the 21st century (i.e., 2081–2100) and find an average increase of 211% and 574% in the frequency of CDWEs and CWWEs, respectively. This study can provide useful insights for mitigation measures and policy development to cope with compound events under global warming.