Significant Increase of the Global Population Exposure to Increased Precipitation Extremes in the Future

Abstract

Abstract Precipitation extremes and associated hazards often cause agricultural losses and infrastructure damage and even exert negative impacts on human health. It is thus crucial to assess future changes in precipitation extremes and exposure under future warming scenarios to improve the mitigation of climate change. On the basis of Coupled Model Intercomparison Project phase 6 simulations, we find that occurring probabilities of precipitation extremes that exceed the 99th percentile threshold are projected to increase over global lands in the coming century, especially under the no‐mitigation scenario of SSP5‐8.5. Under this scenario, by the end of this century, occurrences of aggregations of precipitation extremes over global lands are expected to increase by approximately 1.8 times. Increases are also expected even if early mitigation is conducted via SSP1‐2.6. Accordingly, global aggregate exposure would increase by at least 50% in the future under SSP5‐8.5. Changes in precipitation extremes will exert a substantial influence on population exposure, of which contribution will be up to 46% under SSP5‐8.5 by the end of this century. The future maximum centers of exposure are concentrated over East Asia, South Asia, the Mediterranean basin, and eastern North America, as in the current state. However, the rapid increase in population over some parts of Africa plays a larger role than climate change and significantly increases the exposure in these regions. As a result, regions of Africa will become other high‐exposure global centers in the future. Climate change mitigation should be thus the key policy response to reduce population exposure in the future over most global regions.

Keywords

• precipitation extreme
• population exposure
• CMIP6