Projecting spatiotemporal changes of precipitation and temperature in Iraq for different shared socioeconomic pathways with selected Coupled Model Intercomparison Project Phase 6

Changes in precipitation and temperature have crucial implications in the arid region due to their fragile environment. This study was an attempt to estimate possible spatiotemporal alteration of annual and seasonal precipitation and temperature in Iraq. Statistical downscaling of Coupled Model Intercomparison Project Phase 6 (CMIP6) global climate model (GCM) simulations for different shared socioeconomic pathways (SSP) was utilized. The GCMs were ranked according to their skills in simulating climate research unit (CRU) precipitation and temperature climatology along with their seasonality. Nonlocal model output statistics (MOS) models were implemented using a support vector machine (SVM) for downscaling and projection of selected GCM precipitation and temperature. Results revealed ACCESS-CM2, BCC-CSM2-MR, GISS-E2-1-G and MRI-ESM2-0 GCMs are most suitable for Iraq. The spatiotemporal changes in precipitation indicated a substantial decrease to north (up to -7.8%center dot mm(-1)) while an increase (around 3.0%) to south for different SSPs. Far future (2060-2099) showed both increase and decrease in precipitation than near future (2020-2059). The precipitation was projected to reduce in winter and increase in summer for all climate zones during both periods. The maximum temperature was projected to increase by 4.5 degrees C to the north and 0.9-2 degrees C to the south. In contrast, the minimum temperature was projected to rise by 1.0-3.5 degrees C to both north and south. Both maximum and minimum temperatures may increase; however, more increases might be in winter and less in summer. The minimum temperature increase will be higher than the maximum temperature in the cold northern region and vice versa. Uncertainty in precipitation and temperature projections was higher for the far-future period with higher SSPs than for the near-future period with lower SSPs. The results of this study can guide the development of strategic policies for climate resiliency development in Iraq.

Automated summary

This study attempted to estimate the spatiotemporal changes in precipitation and temperature in Iraq and found that precipitation will decrease in the north and increase in the south, while temperature will increase overall. The study also highlighted the higher uncertainty in future projections.