Spatiotemporal variation of drought in Iraq for shared socioeconomic pathways

Abstract

Semiarid climate has made Iraq one of the most vulnerable regions to droughts. Semiarid climate has made Iraq one of the most vulnerable regions to droughts. Rising temperatures and declining precipitation, as projected by climate models, would aggravate droughts in the country. This study examined the spatiotemporal variation of drought in Iraq using CMIP6 models for the shared socioeconomic pathways (SSPs). The historical simulations of 21 GCMs were evaluated to choose a GCM subset. A support vector machine (SVM) was used to downscaled the simulations of the selected GCM to 0.5° resolution. Downscaled simulations were used to estimate drought employing standardized precipitation evapotranspiration index (SPEI) for the near (2020–2059) and far future (2060–2099) in comparison to the reference period (1975–2014). EC-Earth3-Veg, BCC-CSM2-MR and ACCESS-CM2 performed the best in simulating Iraq's climate. Historical drought simulation revealed northern Iraq is most prone to droughts of all severities and time scales. The projections of drought revealed a decline in drought frequency in the near but a large rise in the late period. A greater decline in the near future and a rise in the far future were projected for SSP2-4.5 and SSP5-8.5. In both scenarios, drought frequency for all severities was projected to decrease between 0 and 40% in the near future, while moderate and severe droughts were to increase by up to 45% in the far future. Most scenarios showed a decrease in extreme droughts up to 30% in the drought-prone northern region, signifying a shift in the extreme drought-prone zone in Iraq. Drought management in Iraq can be benefited from the maps created in this study. The drought projections for SSPs can be used to update the strategies adopted based on RCPs.