Abstract

Surface temperature variability in southwest Asia during 20th century and projected changes from CMIP5 under three emission scenarios for the 21st century are assessed on the basis of a multimodel ensemble mean of 17 CMIP5 runs and two observational datasets. Performance of individual models is also compared against the observations. CMIP5 models show seasonality in biases over southwest Asia. Cold biases over the Himalayan range are more obvious in winter than in summer. The observed climatic warming during the 20th century is very well captured by the CMIP5 models. However, there is a limited agreement between the observations and the CMIP5 models ensemble mean regarding the temperature trends and their spatial distribution over southwest Asia. Surface temperature variability over southwest Asia is best represented by three individual models (BCC, HadGEM and NorESM). Temperature projections for the 21st century demonstrate that annual temperature rise for RCP 8.5 and RCP 4.5 scenarios is 0.55 °C (10 year)−1 and 0.27 °C(10 year)−1. The RCP 2.6 scenario has the lowest warming rate at 0.11 °C (10 year)−1. By the end of the 21st century, the annual mean temperature in southwest Asia is estimated to increase by 0.80 °C to 4.85 °C. This warming is projected to take place mostly around Pakistan and its surrounding areas.