Evaluating Climate Sensitivity to Atmospheric CO<sub>2</sub> in Basra, Baghdad and Mosul: Iraq

Iraq has been suffering from a rising surface air temperature (SAT), causing a general deterioration in ecosystems. Climate sensitivity (CS) which refers to the increase in average SAT caused by a duplication of Carbon Dioxide Concentration [CO2], was estimated by transient local climate response (TLCR) and equilibrium local CS (ELCS). The time series of the spatial annual averages for both [CO2] and air temperature were analyzed and a linear regression model was also used to find annual trends in SAT and [CO2]. Based on historical yearly data for CO2 concentrations (2003–2016), CO2 emissions (2000–2021), and SAT (1971–2022), CS is evaluated concerning three main areas in Iraq: Basra, Baghdad, Mosul and the whole of Iraq. The results showed that yearly mean SAT and [CO2] in Iraq were well fitted by the regression model with the values of 2.11 ppm/year and 0.07 °C/year, respectively. Among the selected provinces, the highest upward trends in SAT and [CO2] were observed in Basra with the values of 2.15 ppm/year and 0.09 °C/year, respectively, mainly caused by the doubling of CO2 emissions from 70 Gt in 2000 to 150 Gt in 2021. The result also shows that the TLCR and ELCS values in Iraq are 2.55 and 3.8 °C, respectively, within the range suggested by the IPCC 5th Assessment Report for Iraq.