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. It is thus vital to investigate changes in drought risk and exposed social economy under climate change. Here, the future global meteorological drought risk is projected for the 2021-2100 period under four combined scenarios of Representative Concentration Pathways and Shared Socioeconomic Pathways (SSPs), i.e., SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5. And then the exposed population and Gross Domestic Product (GDP) under high risk are analyzed. Drought risk will further strengthen in the future under SSP2-4.5, SSP3-7.0, and SSP5-8.5, with large increases distributed in South Asia, the Mediterranean, East Asia, Southeast Asia, and Central America. The strongest increasing trends in drought risk are concentrated in equatorial regions including South Asia, West Africa, and Central America. A large percentage of the population and economy are exposed to high drought risk. The exposed population under the highest risk level is the largest under SSP5-8.5 and the smallest under SSP3-7.0 for regions in North America, while being the largest under SSP3-7.0 for other regions. The exposed GDP under the highest risk level is the highest under SSP5-8.5 and the lowest under SSP3-7.0, while the disparity among diverse scenarios is larger for the rich regions than the developing ones. Plain Language Summary Drought increasingly affects society, economy, and ecosystems as a frequent natural disaster. Drought risk assessment can help understand the extent of drought threat to the human system. Therefore, we projected 0.5 degrees x 0.5 degrees future drought risk for the 2021-2100 period under four scenarios and investigated the exposed population and Gross Domestic Product (GDP) under high risk. We find that high-risk regions mainly concentrate in South Asia, the Mediterranean, East Asia, Southeast Asia, Central America, eastern North America, North Europe, and West Africa, and global drought risk will increase in the future. The population exposed to high drought risk for South Asia, West Africa, and East Asia is much larger than other regions. GDP exposed to high drought risk is the largest for East and South Asia. Large exposed population and GDP occur under high forcing fossil-fueled development pathways. Our findings help policymakers develop adaptive disaster prevention measures.