Climate driven shifts in precipitation and mean temperature in western Iraq (Anbar Province): spatiotemporal projections using LARS-WG 8.0 and CMIP6

Abstract

Understanding the spatial and seasonal redistribution of temperature and precipitation is essential for climate adaptation in arid regions. Although recent studies in Iraq have applied statistical downscaling and CMIP6 projections to selected watersheds and water-resource systems, province-scale assessments of how seasonal temperature and precipitation classes may spatially redistribute across Anbar Province under multi-model CMIP6 scenarios remain limited. To address this gap, this study evaluates near-term spatiotemporal changes in precipitation and mean temperature across western Iraq using LARS-WG 8.0 and a five-model CMIP6 ensemble. The model was applied to daily NASA POWER/MERRA-2 series extracted at seven station-referenced locations for the 1985–2015 baseline period. Climate conditions for 2021–2040 were projected using MRI-ESM2-0, CNRM-CM6-1, HadGEM3-GC31-LL, ACCESS-ESM1-5, and MPI-ESM1-2-LR under SSP245 and SSP585. Projected mean temperature showed an overall warming tendency, although the magnitude and spatial extent of change varied seasonally and between scenarios. Autumn warming under SSP245 and winter warming under both scenarios were spatially limited, whereas more extensive spatial shifts occurred during spring and summer, particularly under SSP585. The largest warming-related spatial shift occurred in spring under SSP585, when the area classified within the 25–30 °C range increased from 71.99% during the baseline period to 96.37%. Seasonal precipitation generally increased in autumn, winter, and spring under both scenarios. The most pronounced redistribution occurred in autumn under SSP245, when the 30–40 mm precipitation class expanded from 16.44% to 75.23% of the study area; in winter, the 40–50 mm class increased from 15.27% to 42.76%. These results provide spatially explicit evidence of near-term climate redistribution across Anbar Province and support water-resource planning and adaptation to increasing hydroclimatic variability in western Iraq.