Glaciers in the spiti sub-catchment of the Satluj basin are receding at a much faster pace than ever before as studies undertaken by experts indicate “deglaciation” of over 25 per cent in the area since 1962 with bigger glaciers retreating at an astounding rate of 65 per cent. These observations were made in the latest Compendium of Environmental Statistics, Himachal Pradesh, 2012-2013, brought out by the Department of Economics and Statistics by putting together data collected from various agencies like the Space Application Centre, Ahmedabad, and the Wadia Institute of Himalayan Geology, Dehradun, and the HP State Council for Science Technology and Environment.
The adverse affects of global warming and climate change are already becoming visible in various parts of the hill state. The study attributes the accelerated melting rate of glaciers to the fact that the maximum and minimum temperatures at almost all locations including Losar, Kaza, Maling and Namgia, have risen. The Spiti valley, where apple cultivation was unheard of till a few years ago, is taking to commercial apple cultivation with people setting up orchards. The snow line, too, has been declining and agro climatic zones have practically been redefined owing to global warming.
The study took into account the monitoring of glaciers with the help of remote sensing and geographical information system (GIS) in order to estimate the retreat in terms of loss of area of the year 1962, 1993, 2001 and 2007. The comparison of the size of the glaciers during these years indicated that 5 per cent of the area was lost between 1962 and 1993, the pace of melting increased to 12 per cent by 2001, which further shot up to 13 per cent by 2007. The glaciers have been retreating, both in spatial as well as linear retreat in the Spiti sub-catchment.
Glacier % loss area no of 1962 area in glaciers sq km 2001 Area in sq km
in sq km
0 to 1 112 43.87 55.12 25.64 (increase)
1 to 3 51 93.26 81.50 12.60
3 to 5 12 49.01 34.43 29.74
5 to 10 08 58.00 36.12 37.72
Over 10 05 66.99 23.67 64.66
Total 188 311.13 230.84
Loss in Area of Glaciers in Spiti Basin Between
1962 and 2001
During the study, it was found that the glacial area of the 188 glaciers taken into account had reduced to 230.84 sq km in 2001 from 311.13 sq km area it had in 1962, thereby indicating an overall reduction of 25.80 percent. While glaciers with an area of more than 10 sq km exhibited the maximum retreat of 65 percent, the ones ranging between five and 10 sq km lost the area by 38 percent while the smaller ones up to 3.5 sq km lost the area by 30 percent. The smallest ones with an area ranging between one to three sq km retreated at 13 per cent.
Data analysis indicated that the number of smaller glaciers with less than 1 sq km area had increased in the area mainly due to the fragmentation of bigger glaciers, triggered by climate variations over a period of time. The comparison of 812 glaciers between 2001 and 2007 indicated that a deglaciation of 11.04 percent had taken place.