Assessment of CMIP5 global climate models and projected changes in surface air temperature over the Arabian Peninsula in the twenty-first century

This study examines the surface air temperature projections and associated uncertainties over the Arabian Peninsula by using data from the Coupled Model Intercomparison Project Phase 5 (CMIP5) under the Representative Concentration Pathways RCP4.5 and RCP8.5 scenarios. The 30-member CMIP5 mean multi-model ensemble (MME) reveals a significant (at the 99% level) increase in temperature by the end of the twenty-first century of around 2.28 (5.53)degrees C/100years under the RCP4.5 (RCP8.5) scenarios. The warming as well as the uncertainty associated with the temperature projections over the Arabian Peninsula will increase with time up to the end of the twenty-first century. In the near future (2021-2050), both RCPs (RCP4.5 and RCP8.5) reveal similar increases (similar to 2 to 2.5 degrees C) in temperature compared to the present climate (1976-2005). For the period 2070-2099, the temperatures are projected to be from 2.55 +/- 1.58 (4.89 +/- 1.58)degrees C relative to the present climate under RCP4.5 (RCP8.5), while the associated uncertainty ranges from -1.38 to 5.95 (0.57 to 7.9)degrees C. Under RCP4.5 (RCP8.5), all models reach 2 degrees C in the Arabian Peninsula in the twenty-first century relative to 1976-2005 from 2023 (2030) to 2062 (2049). The warming over the Arabian Peninsula is projected to be asymmetric that will vary both spatially and seasonally. A strong increase in the annual mean temperature over the central and northwestern parts of the Arabian Peninsula comes mainly from the summer and autumn season. The projected warming rate is higher in the autumn compared to the other seasons during the twenty-first century. The decadal and centurial warming rates are lower in winter and higher in autumn.