Three-dimensional-based global drought projection under global warming tendency

Global warming is anticipated to largely impact drought dynamics. Therefore, a comprehensive projection of global drought under various future warming levels is critical for water resources management. This study investigated the changes in the severity, intensity, area, and duration of droughts at 1.5 degrees C, 2 degrees C, 3 degrees C, and 4 degrees C of global warming above pre-industrial levels based on the latest simulations under climate change scenarios from the Coupled Model Intercomparison Project Phase 6 (CMIP6). The Standardized Precipitation Evapotranspiration Index (SPEI) at 3-month time scale was adopted to characterize seasonal droughts. The results show that: 1) Global land is projected to experience a significant nonlinear increasing trend of drought severity, intensity, areal extent, and duration during the 21st century, and drought characteristics have the highest growth rate under the 3 degrees C warming scenario, followed by the 4 degrees C, 2 degrees C, and 1.5 degrees C warming scenarios. 2) Under the 1.5 degrees C and 2 degrees C warming levels, drought characteristics in most land areas change slightly compared to the baseline period of 1995-2014. 3) Hotspots defined as robust increases in drought severity appear in the 3 degrees C and 4 degrees C warming world, including northern South America, Europe, northern and southern Africa, western and central Asia, and central Australia, whereas eastern North America and the Russian Arctic exhibit substantial reduction in drought severity under different global warming levels. 4) Global warming is projected to change the timing of droughts, leading to more frequent summer droughts in Europe. Overall, the findings of this study provide a scientific basis for articulating future global drought adaption and highlight the need for mitigation measures to limit greenhouse gas emissions to achieve the 2 degrees C target of the Paris Agreement.

Automated summary

Global warming is expected to have a significant impact on drought dynamics. This study investigated the changes in drought severity, intensity, area, and duration under various levels of global warming. The results showed a nonlinear increasing trend in drought characteristics, with the highest growth rate under 3 degrees C warming. Hotspots of increased drought severity were identified, while some regions exhibited a reduction in drought severity. The findings emphasize the need for adaptation measures and mitigation of greenhouse gas emissions.