Glaciers in the Baspa basin of Himachal Pradesh are receding fast. The trend can soon create scarcity of water in the region, according to researchers from the Ahmedabad-based Marine and Water Resources Group of the Indian Space Research Organisation. Of the 30 glaciers in the basin, the researchers studied 19 representing an area of about 140 square kilometres. They found that 18 glaciers were retreating. During 1962-2001, water stored in them dipped by 23 per cent and they retreated by 19 per cent on an average. In some cases, the loss was about 50 per cent.
Glaciers located at lower altitudes showed greater retreat rates -- those located at an altitude of around 5,000 metres have lost 24 per cent of ice cover, while those at 5,400 metres and above have retreated by 14 per cent. The phenomenon has been attributed to the fact that low altitude glaciers are protected by debris that can retard melting and make the ice cover less sensitive to climatic changes.
In an earlier study, the researchers had found that stream runoff of Baspa river had increased by 75 per cent on an average that too in the month of December from 1967 to 1995. Shrinking of glaciers and consequent glacial melt may have increased the runoff, but the authors caution this is only temporary. In the long-term, as the glacial size keeps decreasing, it will reduce the runoff, leading to serious water shortage in the region.
The glaciers are part of the Himalayas and their rugged terrain does not allow the use of conventional methods to collect information. Therefore, images obtained through remote sensing were used for monitoring glacial features like accumulation and ablation area. Images of July-September were selected, as snow cover is minimum during these months.