Abstract:
Drought is one of the most widespread natural disasters, and examining its effects on ecosystems is essential. This study presented the impact of climate change on Iraq's meteorological drought using advanced climate model techniques and projections from Phase 5 and Phase 6 of the Coupled Model Intercomparison Project (CMIP5 and CMIP6). The study applied the artificial neural network (ANN) based statistical downscaling techniques (SDSM). It developed region-specific forecasts under two emission scenarios, Representative Concentration Pathway (RCP) 4.5 and RCP8.5, based on 29 global circulation models (GCMs) from CMIP5 and 25 from CMIP6. Ensemble1 (ENS1) was identified as the best-performing model for precipitation, while MIROC5 was the best for temperature. The analysis was conducted for 2024–2100, based on historical baselines from 1979 to 2013.
The Standardized Precipitation Index (SPI) and Standardized Precipitation-Evapotranspiration Index (SPEI) were considered when analyzing droughts of shorter or longer time scales. Top performance GCMs show that seasonal precipitation will decrease by up to 11.5%, 25.5%, and 25.7% for winter, spring, and autumn, respectively, under RCP4.5, and up to 23.7%, 41.9%, and 37.2% under RCP8.5 toward the end of the century, with significant effects on the central and southern regions, especially
Basrah, Muthanna, and Najaf. In the process, temperatures may rise by 1.7°C, 2.0°C, 1.0°C, and 2.2°C for winter, spring, summer, and autumn, respectively, under RCP4.5. Under RCP8.5, temperatures may rise by 3.3°C, 3.0°C, 1.2°C, and 3.2°C for winter, spring, summer, and autumn, respectively, thus leading to heightened evapotranspiration (ET) levels and worsening drought conditions in already water-stressed areas, such as those in the southern parts of the country. Areas reliant on the Tigris and
Euphrates rivers will be at risk from reduced river flows and upstream usage by neighboring countries. Time-series analysis indicates a significant trend for increased frequency and severity of drought, especially under RCP8.5, which could double by the middle of this century. Even in northern Iraq, where mild precipitation decline is projected, the temperature rise would increase aridity and negatively impact agriculture and food security.
