Expansion of glacial lakes in the Himalayas is a matter of concern
New Delhi:
At least 89 per cent of the 2,431 glacial lakes in the Himalayas identified in 2016-17 have experienced significant expansion since 1984, the Indian Space Research Organization (ISRO) said in a report today.
Experts say the results of the ISRO analysis are worrying because the expansion of glacial lakes due to warming could have widespread consequences in downstream areas. ISRO said satellite data collections over the past three to four decades provide valuable insights into changes in the glaciated environment.
ISRO said in the report that long-term satellite imagery covering catchments of Indian Himalayan river basins from 1984 to 2023 indicates significant changes in glacial lakes.
The ISRO report said 601 glacial lakes, or 89 per cent, have expanded more than double, and 10 lakes have expanded between 1.5 times and up to double their size. Sixty-five lakes have expanded 1.5 times.
Of the 2,431 glacial lakes larger than 10 hectares, 676 have expanded significantly, and at least 130 of these lakes are in India – 65 (Indus River Basin), 7 (Ganga River Basin), and 58 (Brahmaputra River Basin). .
Altitude-based analysis shows that 314 lakes are located in the 4,000 to 5,000 m range, and 296 lakes are above 5,000 m altitude, ISRO said in the report ‘Satellite Insights: Expanding Glacial Lakes in the Indian Himalaya’ released today. .
ISRO said long-term changes in the Ghepang Ghat glacial lake (Indus River Basin), located at an altitude of 4,068 meters in Himachal Pradesh, predict a 178 per cent increase in size between 1989 and 2022 from 36.49 to 101.30 hectares. The rate of growth is about 1.96 hectares per year.
Long Term Changes in the Ghepang Ghat Glacial Lake Area (ISRO)
ISRO said satellite-derived long-term change analyzes also provide valuable insights to understand glacial lake dynamics, which can be useful for assessing environmental impacts and for glacial lake outburst flood (GLOF) risk management and climate change adaptation in glacial environments. are necessary to develop strategies.
ISRO said the study faced challenges due to inaccessible and rugged terrain. Satellite remote sensing technology, however, serves as an excellent tool for inventory and monitoring due to its wide coverage and revisitability, the space agency said.
The Himalayan mountains are often called the “Third Pole” because of their extensive glaciers and snow cover, and they are highly sensitive to changes in global climate, both in terms of their physical characteristics and their social impacts.
ISRO said in the report 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 18th century.
This withdrawal leads to the formation of new lakes and expansion of existing lakes in the Himalayan region. These bodies of water formed by melting glaciers are known as glacial lakes and play an important role as a source of freshwater for rivers in the Himalayan region.
However, they also pose significant risks, such as 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 dams made of ice, resulting in sudden and severe flooding. These dam failures can be caused by a variety of factors, including snow or rock avalanches, extreme weather events, and other environmental factors.
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