Increased Likelihood and Intensification of Global Agricultural Droughts Under Compound Meteorological Droughts and Hot Extremes

Abstract

Soil moisture deficits, or agricultural droughts, play a critical role in agricultural water management. Agricultural droughts are primarily driven by precipitation shortages (meteorological droughts) and increased evapotranspiration demand associated with high temperatures. However, despite the growing recognition of the impact of compound meteorological droughts and hot extremes (CDHEs), a global‐scale assessment of how elevated temperatures intensify soil moisture deficits across different climate zones remains insufficient. In this study, we quantify the impacts of CDHEs on soil moisture deficits across global land areas and different climatic zones. Compared with meteorological drought‐only periods, the probability of soil moisture deficits increases by 50.91% and 62.16% in surface and root‐zone soil layers, respectively. Soil moisture deficits are also more severe under CDHEs than under meteorological droughts alone. Random forest models combined with SHAP (SHapley Additive exPlanations) analysis reveal distinct driving mechanisms across climate zones. In dryland, precipitation differences are the primary driver of soil moisture differences between meteorological droughts and CDHEs. In contrast, differences in temperature and vapor pressure deficit (VPD) under the two extremes dominate the differences in surface and root‐zone soil moisture, respectively. Moreover, we observed a decreased sensitivity of agricultural droughts to CDHEs in drylands from 1981–2001 to 2002–2022. These findings improve our understanding of CDHE impacts and provide valuable insights for agricultural drought risk assessment under climate change.