(Aug11– Glacier sizes are rapidly reducing due to the impact of climate change in recent years, resulting in a gradual rise of moraine-dammed lakes in Himachal Pradesh in India and the Trans Himalayan Region of Tibet, posing a potential threat to human life and infrastructure further downstream, reported thehindu.com Aug 10, citing a recent study.
Moraine-dammed lakes are formed by the melting of retreating glaciers whose deposits of earth, rock etc, had fortified to prevent the water from flowing out.
The number of glacial lakes in the Satluj river (Tibetan: Langchen Khabab) catchment area has almost doubled from 562 in 2019 to 1,048 in 2023, the report said, citing satellite data analysed in a recent study by the Centre on Climate Change of Himachal Pradesh Council for Science Technology-Environment (HIMCOSTE).
Of these 1,048 lakes, 900 are small, each spanning an area of less than five hectares, while 89 have an area between 5 hectares and ten hectares, and 59 are bigger than 10 hectares each, the report added.
The catchment area of the Satluj basin was studied from upstream of Jhakri in Shimla district of Himachal Pradesh to the Mansarover Lake (Mapham Yutso) in Tibet in the Trans Himalayan Region from where the river originates.
“Over the years, the number of glacial lakes has been gradually increasing. In fact, as the frequency of small lakes with an area of less than five hectares has been rising, it indicates that the climate warming effects are more significant in the higher Himalayan region. The swift melting of glaciers and less snowfall during the winter could be reasons behind the rise in lakes,” Mr SS Randhawa, a co-author of the study, and the principal scientific officer at HIMCOSTE, has said.
Randhawa has said it could be inferred from the basin-wise analysis that the number of lakes is much higher in the Tibetan Himalayan Region or the Upper Satluj basin, in comparison to the Spiti and Lower Satluj basins, indicating that the Upper Satluj basin is more susceptible to glacial lake formations.
The study, which analysed multi-spectral satellite images, suggests that the rise in glacial lakes in Himachal Pradesh’s river basins can be disastrous downstream if the lakes burst their bounds for any reason, the report said. It was not clear from the news report whether similar danger existed on the Tibetan side of the Satluj basin where the number of such lakes is higher.
“Climate change has influenced the health of glaciers in the entire Himalayan region. As a result, the cryospheric cover over the Himalayan terrain is reducing. One of the ramifications of this is the development of high-altitude glacial lakes,” Sunil Dhar, Dean of the Department of Environmental Sciences at the Central University of Jammu, has said.
“The number of such lakes has increased over the years and these lakes have become unstable due to the increase in the volume of water or due to the calving effect of adjoining glaciers, [creating] avalanche either of snow or rocks. These lakes have a potential of bursting out, and depending on the volume of water, velocity and the outburst spread, it can pose a threat to habitations and infrastructure in the downstream region,” he has added.