Understanding the Dynamics of Record‐Shattering Compound Drought‐Heatwave Events and Their Impacts on Ecosystems
Bohao Li, Kai Liu, M. Wang, Yuanhang Yang, Mingzhu He, Yanfang Wang, Chenxia Li, Di Wang
Abstract
Abstract Recently, unprecedented compound drought and heatwave (CDHW) events have severely damaged terrestrial ecosystems, but their dynamics, formation mechanisms, and threats are still insufficiently understood. Here, using simulations from nine‐member ensemble under three future scenarios, we project that the expected annual probability of record‐shattering CDHW events (i.e., events exceeding historical severity records by more than two standard deviations) will double between 2015 and 2040 and continue to rise throughout the 21st century under the SSP5‐8.5 scenario (0.05% per year). The mean temperature, relative humidity, shortwave radiation, and precipitation are critical drivers of CDHW severity. Record‐shattering CDHW events severely impact ecosystems, particularly in regions such as southern North America, northern South America, and southern Europe. Observational data from 1951 to 2022 indicate that compared to nonrecord‐shattering CDHW events, record‐shattering CDHW events are correlated with weaker water vapor transport, reduced convective activity, and greater ecosystem damage, resulting in an additional global mean gross primary productivity (GPP) loss of −2.76 to −3.96 g C m −2 month −1 . Between 2080 and 2099, the global average GPP anomalies caused by these events are projected to range from 46% to 119% of the warm season's monthly average ecosystem carbon sink. Our study underscores the urgent need for adaptive measures to mitigate the ecological threats from record‐shattering CDHW events to ensure ecosystem sustainability.