Projecting global drought risk under various SSP-RCP scenarios

Drought risk assessment can identify high-risk areas and bridge the gap between impacts and adaptation. However, very few dynamic drought risk assessments and projections have been performed worldwide at high spatial resolution (e.g., 0.5{degree sign} × 0.5{degree sign}) under different greenhouse gas emission scenarios. Here, future global drought risk is projected combing three components (i.e., hazard, exposure, and vulnerability) during 2021-2100 under combined scenarios of Representative Concentration Pathways (RCPs) and Shared Socioeconomic Pathways (SSPs): SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5. This study first investigates dynamic drought risks and exposed population and GDP across the six continents (Antarctica is not examined due to data availability). The results show that high-risk regions mainly concentrate in southeastern China, India, Western Europe, eastern United States, and western and eastern Africa. Drought risk will further strengthen in the future under four scenarios, with the highest under SSP5-8.5 and the lowest under SSP3-7.0. Populations exposed to high drought risk for Asia and Africa are much more than other continents. Among four SSP-RCPs, populations exposed to high risk are the largest under SSP3-7.0 for Africa, Asia, and South America, while under SSP5-8.5 for Australia, Europe, and North America. GDP exposed to high drought risk is the largest for Asia among the six continents and the largest under SSP5-8.5 among the SSP-RCPs. The most significant increases in population and GDP under high drought risk both occur in Africa. This study provides a scientific basis for effective adaptation measures to enhance drought resilience in potential high-risk areas.