Climate Change Over the Himalayas
T. P. Sabin, R. Krishnan, Ramesh Vellore, P. Priya, H. P. Borgaonkar, Bhupendra Bahadur Singh, Aswin Sagar
Abstract
The Himalayas and the Tibetan Plateau have experienced substantial warming during the twentieth century. The warming trend has been particularly pronounced over the Hindu Kush Himalaya (HKH) which is the largest area of permanent ice cover outside the North and South Poles. The annual mean surface-air-temperature in the HKH increased at a rate of about 0.1 C per decade during 1901-2014, with a faster rate of warming of about 0.2 C per decade during 1951-2014, which is attributable to anthropogenic climate change (High confidence). Additionally, high elevations (> 4000 m) of the Tibetan Plateau have experienced stronger warming, as high as 0.5 C per decade, which is commonly referred to as elevation-dependent warming (EDW). Several areas in the HKH have exhibited declining trends in snowfall and retreating glaciers during the recent decades. Parts of the high-elevation Karakoram Himalayas have, in contrast, experienced increased wintertime precipitation in association with enhanced amplitude variations of synoptic western disturbances (Medium confidence). Future climate projections under various CMIP5 scenarios suggest warming of the HKH region in the range of 2.6-4.6 C by the end of the twenty-first century. While future projections indicate significant decrease of snowfall in several regions of the HKH, high-elevation locations (> 4000 m) in the Karakoram Himalayas are projected to experience an increase in annual precipitation during the twenty-first century.