Projected increase in global compound agricultural drought and hot events under climate change

Compound agricultural drought and hot events (CADHEs, co-occurring soil moisture depletion and high temperature) have intensified over the last decades and are expected to further rise in view of climate change. Such increasing climate hazards have the potential to push agricultural systems towards critical tipping points with dramatic consequences for human societies. Despite the urgency of this issue, the future evolution of CADHEs characteristics in response to changing environmental conditions remains poorly quantified. Here, we propose a multivariate probabilistic assessment framework based on a copula function to integrate the key characteristics of CADHEs — duration, intensity, and severity — and project future CADHEs dynamics. To this aim, CADHEs are identified based on the joint distribution of standardized soil moisture index (SSI) and standardized temperature index (STI) retrieved for the mid-term (2021–2060) and long-term (2061–2100) periods from an ensemble of nine Coupled Model Intercomparison Project Phase 6 (CMIP6) Global Climate Models under two Shared Socioeconomic Pathways (sustainability pathway and high-emissions pathway: SSP1–2.6 and SSP5–8.5). Results show that the likelihood of CADHEs is projected to increase globally throughout the 21st century compared to the baseline period (1975–2014), with a more pronounced increase under SSP5–8.5. Northern Africa, the Middle East, and South Asia emerge as key hotspots where longer duration, greater intensity, and higher severity are expected to manifest simultaneously. Under SSP5–8.5, these hotpots are expected to expand further compared to SSP1–2.6, particularly in the long-term period. Our findings provide useful input for forthcoming global disaster risk and adaptation policy, ultimately contributing to the long-term stability of agricultural systems and food security.