Projected changes in population exposure to drought in China under CMIP6 forcing scenarios

Droughts are among the most common and widespread natural disasters, severely affecting several aspects of human society. It is of vital importance to assess the drought impacts under climate change. Herein, we investigated the evolution and characteristics of drought for both historical (1980-2019) and future (2020-2100) periods in China under three representative pathways (SSP1_26, SSP2_45, and SSP5_85) using the Standardized Precipitation Evapotranspiration Index and multiple Global Climate Models from the Coupled Model Intercomparison Project Phase 6. Further, we evaluated the changes in population exposure to drought for the near (2020-2059) and distant (2060-2100) future by combining the drought frequency with the projected population from the Shared Socioeconomic Pathways (SSPs). The results showed that drought areas and intensities would generally decrease slightly in the near future but would increase substantially in the distant future. Moderate droughts would occur more frequently under all scenarios in the near future, whereas severe and extreme droughts would be more frequent in the distant future. In the near future, population exposure to moderate, severe, and extreme droughts would increase by 15.3%, 31.8%, and 68.0%, respectively, under SSP1_26, whereas it would decrease by 31.9%, 50.2%, and 62.3%, respectively, under SSP5_85. At the end of this century, a widespread increase in exposure to severe and extreme droughts is likely under SSP2_45 and an increase in exposure to all types of droughts is likely under SSP5_85; the greatest increase in exposure (83.8%) is found in the case of extreme drought under SSP5_85. In summary, population exposures varied among different study periods and climate scenarios in China. Therefore, this study calls for both short- and long-term drought mitigation and adaptation measures for potential climate change in China.