Global data assessment and analysis of drought characteristics based on CMIP6

Drought is a severe and chronic natural hazard that deeply affects production and livelihoods. Its characteristics and propagation have been extensively discussed, but the effects of temperature, evapotranspiration, and runoff on drought under different carbon emission conditions are still worth considering. Combining with the release of the Sixth International Coupled Model Intercomparison Project (CMIP6), datasets of multiple patterns were compared with observational datasets. The most available data were screened to verify the accuracy of CMIP6 and were used to determine global Standardized Precipitation Index (SPI), Standardized Precipitation-Evapotranspiration Index (SPEI), and Standardized Runoff Index (SRI) to analyze global drought properties, such as frequency, duration, and spatial extent. According to the Shared Socioeconomic Pathways (SSPs) scenarios, drought properties in the future were compared with those in the past and results were as follows: First, more accurate precipitation and evapotranspiration data were provided by the CanEMS5, and more accurate soil moisture data were provided by the BCC-CSM2-MR. Second, in the 21st century, the frequency, duration and spatial extent of global drought in most areas would increase. Finally, the key influencing factor of drought would the evapotranspiration. The relationship among rainfall, runoff, and temperature was mutually binding. Overall, global droughts, in particular exceptional droughts, showed a progressive worsening of conditions and a marked increase in the future. This study provides a reference for exploring global drought changes under climate change and provides a basis for the application of the CMIP6.

Automated summary

This study, using the latest climate model data, found that in the 21st century, the frequency, duration, and spatial extent of global drought in most areas would increase, with evapotranspiration being a key influencing factor.