Drylands face potential threat of robust drought in the CMIP6 SSPs scenarios

Abstract

In an increasingly globalized and warming world, drought can have devastating impacts on regional agriculture, water resources, and the ecological environment. Reliable prediction of future drought changes is especially important within the context of rapid warming. However, the extent and future trends of drought changes are variable and incomplete in the CMIP6 forcing scenarios. Based on the CMIP6 data, we chose the standardized precipitation-evapotranspiration index to predict future global drought. The results show that when emissions increase under the three shared socioeconomic pathway (SSP) scenarios (SSP126, SSP245 and SSP585), the global climate environment becomes drier and drought grow more severe and longer-lasting. Regions already classified as arid will suffer even more severe drought under high-emission SSPs. Specifically, 36.2% of global land will experience increased drought under SSP126, including 67.0% of regions designated as arid, with droughts intensifying significantly. Under SSP585, 68.3% of global land will suffer increased drought, with 93.2% of the arid regions experiencing significant drought intensification. Furthermore, the global duration of drought is estimated to be 4.4 months, 5.7 months, and 8.6 months for the time periods 1960-2000, 2021-2060, and 2061-2100, respectively. Notably, for the SSP585 scenario, regions that are already arid may become universally drought-stricken by the late 21st century. The most severe aridification trends may occur in the arid regions of Australia, Middle East, South Africa, Amazon basin, North Africa, Europe, and Central Asia. Additionally, Europe and the Amazon River Basin are also facing the threat of future drought. Increased aridification will put these regions and countries at risk of further land and ecological degradation, as well as increased poverty. The results of this study have far-ranging implications not only for how we deal with the impacts of climate warming-induced drought disaster, but also for how these impacts affect socio-economic and ecological security.