Climate change and predicting future temperature in Iraq using CanESM2 and HadCM3 modeling

Abstract

Climate change and global warming have become a major environmental threat, especially for dry countries. Identifying and assessing future climate change are, therefore, paramount for suitable environmental planning to adapt to and reduce their effects. In this study, changes in the maximum and minimum temperatures in southwest Iraq during the period 2020–2099 were generated using two general circulation models (GCMs), CanESM2 and HadCM3, based on two special report emission scenarios (SRES), A2 and B2, and three representative concentration pathway (RCP) scenarios (RCP2.6, RCP4.5, and RCP8.5). Seven meteorological stations representing the study area were selected for model calibration and validation in the statistical downscaling model (SDSM) based on the observed period 1979–2018. The statistical indexes showed a good agreement between the downscaling and observed temperature data for seven meteorological stations in Iraq, where determination coefficient R2 ranged from 0.861 to 0.918 and 0.855 to 0.896 for maximum and minimum temperature, respectively. For the major changes, the results exhibited an increase in mean annual maximum temperature of between 0.48 and 2.5 ℃ (RCP8.5) over the stations by the end of the twenty-first century, while the minimum temperature is expected to rise by 0.22 ℃ (RCP2.6) and 1.76 ℃ (RCP8.5). This increase will affect water resources, because increased surface water evaporation causes water scarcity. HadCM3 shows greater maximum temperature changes than CanESM2 across Iraq.