Human Influence On The Unprecedented 2022 Extreme Dragon Boat Water Event Over South China: Insights from Historical and Projected Perspectives

Abstract

During May–June 2022, South China experienced an unprecedented extreme dragon boat water event (2022 EDBWE) characterized by persistent heavy precipitation. The maximum cumulative precipitation over a consecutive 31-day period (May 21–June 20, 2022; Rx31day) was anomalously 74% higher than the historical average, resulting in record-breaking rainfall that caused significant socioeconomic losses as well as casualties. Nevertheless, human influence is yet to be decisively linked to the occurrence of the 2022 EDBWE or the likelihood of similar future extreme events under various Shared Socioeconomic Pathway (SSP) scenarios. Thus, in this study, we aimed to utilize data from the Detection and Attribution Model Intercomparison Project and Scenario Model Intercomparison Project within the Coupled Model Intercomparison Project Phase 6 and assess the influence of anthropogenic activities on similar extreme events, both historically and through future projections for South China. Results indicate that the anthropogenic forcing has reduced the probability of an event similar to the 2022 EDBWE by approximately +64% (-88% to +94%). The greenhouse gas-only and aerosol-only forcings have increased and decreased this probability by +66% (-24% to +95%) and -28% (-982% to +82%), respectively. Furthermore, under different SSP scenarios, namely SSP1-2.6, SSP2-4.5, and SSP5-8.5, the likelihood of an event similar to the 2022 EDBWE increases substantially. By the end of the 21st century, an event similar to the 2022 EDBWE is approximately 11 times more likely to occur under the high emissions scenario (SSP5-8.5) than under historical climate conditions. Overall, this manuscript helps us choose the appropriate measures to address climate change.

Keywords: dragon boat water event, extreme precipitation, future projections, South China