Recent glacier area changes in Himalaya–Karakoram and the impact of latitudinal variation

We present the observed area changes in 5234 glaciers (out of which 3435 are debris-free) of Himalaya–Kara­koram (H–K) region, mapped at a scale of 1 : 25,000 using primarily IRS LISS III data between the years 2001 and 2016/2017/2018. Area change is a direct observable parameter in the monitoring of glaciers. The mapping results have been analysed in different sectors of H–K region. In the Karakoram region, 2143 glacier bodies with an area coverage of 18343.39 km2 show a gain of 0.026%, whereas in Himalayan region, 3091 glaciers covering an area of 11451.53 km2 show a loss of 1.44% over a span of 17 years. Loss in glacier area in Himalayan region varies from 0.76% in sub-basins located in the left side of NW flowing Indus River (N–W Himalaya/J&K and Ladakh), 2.2% in Chenab and Sutlej basins (Western Himalaya/Himachal Pradesh), 0.84% in Ganga basin (West-Central Himalaya/Uttarakhand), 2.16% in Ganga basin (Central Himalaya/Nepal and a few glaciers of Tibetan region) and 2.15% in Tista sub-basin (Eastern Himalaya/Sikkim). The mapping uncertainty is less than 0.01%. The results also show that debris free glaciers are more vulnerable to global warming thereby affirming the earlier theories of differential impact of warming on debris free and debris covered glaciers. Overall, the statistics clearly indicate the effect of latitudinal variations on the gain/loss in the area of glaciers from higher to lower latitudes in addition to microclimatic and geomorphological factors