Dynamical downscaled CMIP5 scenario–based future climate changes over the Arabian Peninsula

Climate change is one of the most important challenges for humanity at present, and its impacts are especially profound in semi-arid regions such as the Arabian Peninsula and Saudi Arabia in particular, as it directly impacts the fragile ecosystem of the region. The present study explores the changes in future temperature and precipitation patterns over the Arabian Peninsula for the two future time slices 2036–2065 and 2071–2100 with respect to the reference period (1976–2005), using state-of-the-art regional climate model simulations. Three global climate model (GCM) simulations from the WCRP Coupled Model Intercomparison Project Phase 5 (CMIP5) are downscaled with the International Centre for Theoretical Physics (ICTP) Regional Climate Model (RegCM4) over the Arabian Peninsula. Results indicate that the central parts of the Arabian Peninsula should get hotter in future compared to other parts of the Peninsula. This projected increase in temperature seems to happen mainly at the end of the twenty-first century. The projected temperature changes during mid-century fall in the range 1.0–1.5 °C under the RCP4.5 scenario and 2.0–2.5 °C under RCP8.5. Temperature changes by the end of the century are in the range 4–4.5 °C under RCP4.5 and 4.5–5.5 °C under RCP8.5. At the same time, this increase in temperature will affect the annual precipitation cycle as the precipitation during the dry season is expected to increase while the precipitation during the wet season is expected to decrease. RegCM simulations driven with boundary conditions from three GCMs are not consistent in producing future changes in precipitation over Saudi Arabia, which indicates that a careful interpretation of projected precipitation is required for its further use in impact and adaptation studies related to climate change.