IHG (Institute of Himalayan Glaciology)-

Glaciers and Glaciology

Glacier ice presently covers about 10.7% of the total land area or about 3.1% of the global area. Two major ice sheets, namely Antarctica and Greenland, cover the largest extent of the world's ice. These two ice sheets cover about 85.65% and 10.88% area, respectively of the total available ice extent in the world. Together, Antarctica and Greenland sheets occupy about 96.5% of the total area covered by ice. About 75% of the world's total freshwater is stored in the form of glacier ice and out of which 90% is stored in Antarctica alone. The mean thickness of glacier in Antarctica is 2488m whereas maximum thickness goes up to 4700m. Greenland contains about 9% of ice by volume and its mean thickness is 1667m whereas maximum thickness is about 3400m. The rest of ice, which represents about 3.5% of the total area covered by ice, is in the form of mountain glaciers and ice caps on mountain ranges. North America contains about 280,000 km2 ice cover, whereas Asia and Confederation of Independent States (CIS) occupy about 180,000 km2. Europe has about 53,967km2 ice cover and South America has 25,908km2. New Zealand and Subantarctic islands has about 7, 860 km2 ( source: website of NASA 2003). About 10,9000 km2 of mountain ranges of south-central Asia, including Karakorum, Kun Lun Shan, Hindukush and Pamir are covered by ice and snow. According to glacier inventory prepared and published by Geological Survey of India (source: GSI 1999- Inventory of the Himalayan Glaciers, Spl. Publ. 34, pp. 165), the total glacierised area in the Indian part of Himalaya is about 38,000 km2. Although, relatively small quantity of permanent snow and ice accumulate over the mountains, outside the Polar Region, yet it is of great importance for humankind because large number of rivers emanate from these glaciers and/or snowfields, that provides sustenance to innumerable towns/cities/villages situated on these rivers. Glaciers of High Asia drain into the landmass of Indian subcontinent. These glaciers serve as large storehouse of water - storing water in winters and releasing it in summers. These snow and ice fields also hold significance in influencing climate over a short and/or long period. The glaciers are highly sensitive segment of earth's system and are considered as key indicators to monitor global warming. The complex interaction of atmosphere, crustal surface, internal dynamics and characteristics of water-snow-ice-glacier regime govern the sensitivity of glaciers.