Climate change: Glacial lakes in the Indian Himalayas are melting at unprecedented rates

“This retreat leads to the formation of new lakes and expansion of existing lakes in the Himalayan region. These bodies of water formed by the melting of glaciers are known as glacial lakes and play an important role as a source of freshwater for rivers in the Himalayan region,” ISRO said in a release.

“They also pose significant risks such as glacial lake outburst floods (GLOFs), which can have devastating consequences for downstream communities. “GLOFs occur when glacial lakes release large amounts of meltwater due to the failure of natural dams, such as moraines or ice dams, resulting in sudden and severe flooding,” the release said.

It is important to note that research conducted around the world has consistently shown that glaciers around the world are experiencing unprecedented rates of retreat and thinning since the beginning of the Industrial Revolution in the eighteenth century.

Using satellite imagery from 1984 to 2023, ISRO noted that of the 2,431 glacial lakes of the Indian Himalayas – 676 glacial lakes larger than 10 hectares – identified during the 2016-17 satellite survey have expanded since 1984. It includes 130 lakes located within India – 65 lakes located in the Indus River Basin, 7 in the Ganges River Basin and 58 lakes located in the Brahmaputra River Basin.

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The Bengaluru-based Indian Space Agency further said that 89% of the lakes (601 out of 2,431 lakes) have expanded more than double, 10 lakes have expanded by 1.5 to 2 times and 65 lakes have expanded by 1.5 times their size in 1984. Have gone.

The ISRO study further states that 314 lakes are located in the range of 4,000 to 5,000 meters and 296 lakes are above 5,000 meters altitude.

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Glacial lakes are classified into four broad categories based on their formation process, namely moraine-dammed (water dammed by moraines), ice-impounded (water dammed by ice), erosion-disrupted (water dammed in depressions formed by erosion ), and other glacial lakes. Of the 676 extant lakes, most of them are moraine-dammed (307), followed by erosion (265), other (96), and ice-dammed (8) glacial lakes, respectively.

Long-term changes in the Ghepang Ghat glacial lake (Indus River Basin), located at an altitude of 4,068 meters in Himachal Pradesh, lead to a 178% increase in size between 1989 and 2022 from 36.49 hectares to 101.30 hectares. The rate of growth is approximately 1.96 hectares per year.

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Published: April 22, 2024, 08:52 PM IST