130 glacier lakes expanded in India, heightened risk of devastating floods

Rising temperatures are causing rapid melting of snow in the Himalayas, leading to an increase in the size of glacier lakes, according to the latest trend, highlighted in a new report by the Indian Space Research Organization (ISRO). The report suggests a heightened risk of devastating floods if the process continues unchecked.

ISRO finds 27% Himalayan lakes expanded since '84, 130 in India

ISRO's report reveals that over 27% of glacier-formed lakes in the Himalayas have expanded since 1984, with 130 of them located in India. Long-term satellite images covering the catchments of Indian Himalayan river basins from 1984 to 2023 show significant changes in these lakes.

Out of 2,431 lakes larger than 10 hectares identified during 2016-17, 676 were glacier-fed lakes that have grown in size since 1984. Among these, 601 lakes have more than doubled in size, indicating a concerning trend.

The report further details that 130 of these expanding lakes are situated in India, with 65 in the Indus River Basin, seven in the Ganges River Basin, and 58 in the Brahmaputra River Basin. Altitude-based analysis shows that a majority of these lakes (314) are located in the range of 4,000 to 5,000 meters, with 296 lakes situated at altitudes above 5,000 meters.

Glacier-formed lakes are categorized into four main types based on their formation process: moraine-dammed, ice-dammed, erosion-formed, and others. Moraine, which refers to the debris carried by glaciers, plays a significant role in the formation of these lakes.

Among the lakes that have expanded, the majority are moraine-dammed (307), followed by erosion-formed (265), others (96), and ice-dammed (eight) glacier-formed lakes. This data underscores the urgent need for monitoring and mitigating the impacts of climate change on the fragile Himalayan ecosystem.

According to ISRO's report, the Ghepang Ghat Glacial Lake in the Indus Basin, situated at an altitude of 4,068 meters in Himachal Pradesh, has experienced significant long-term changes. Between 1989 and 2022, the lake's size expanded from 36.49 hectares to 101.30 hectares, marking a remarkable 178% increase. This equates to an average annual growth rate of approximately 1.96 hectares per year.

Sikkim tragedy highlights Himalayan vulnerability

In October, tragedy struck Sikkim when South Lhonak Lake burst, claiming 40 lives and leaving 76 missing due to heavy rains. Located at an elevation of 17,000 feet, this event underscored the Himalayas' vulnerability to climate shifts, earning them the moniker "Third Pole."

Global research confirms glaciers worldwide are receding rapidly due to human-induced climate change. As glaciers retreat, they give way to new lakes and swell existing ones. These water bodies, known as glacial lakes, serve as vital freshwater sources for Himalayan rivers but also pose grave risks, notably glacial lake outburst floods (GLOFs).

However, these lakes also bring significant risks like Glacial Lake Outburst Floods (GLOFs), which can wreak havoc on downstream communities.

GLOFs happen when glacial lakes burst their natural dams, releasing vast amounts of meltwater. This sudden flood downstream can result from various triggers, including ice or rock avalanches and extreme weather events.

Satellite remote sensing offers a promising solution, aiding in monitoring and understanding glacier lake dynamics. ISRO's report underscores the urgency of studying these changes to assess glacier retreat rates, anticipate GLOF risks, and comprehend climate change impacts.

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