Himalayan glacial lakes saw their area increase by 10.81% between 2011 and 2024: report

A man digs while trying to recover a vehicle submerged in mud in the flood-affected area along the Teesta River in Rongpo, East Sikkim, India, Sunday, October 8, 2023. Rescuers continued to dig through muddy rubble and icy waters in a hunt for survivors after a glacial lake burst through a dam in India’s northeastern Himalayas shortly after midnight Wednesday, washing away homes and bridges and forcing thousands to flee. | Photo credit: AP

Glacial lakes and other water bodies across the river In the Himalayan region, the area had increased by 10.81% from 2011 to 2024 due to climate change, indicating an increased risk of glacial lake floods (GLOFs), according to a government report.

The Central Water Commission (CWC) report, which was accessed PTIstates that with an increase in area by 33.7%, India’s lakes saw an even more substantial increase.

Also read | Glacial lakes rise as glaciers retreat

“The total inventory area of ​​glacial lakes in India was 1,962 hectares in the year 2011, which has increased to 2,623 hectares in the year 2024 (September). There has been an increase of 33.7% in area,” the report said.

It also identified 67 lakes in India that witnessed an increase of more than 40% in area, putting them in the high-risk category for potential GLOFs.

Ladakh, Himachal Pradesh, Uttarakhand, Sikkim and Arunachal Pradesh showed the most notable expansions, indicating an increased risk of GLOFs and the need for intensified monitoring and disaster preparedness.

Glacial lakes and other water bodies in the Himalayan region saw a total area increase of 10.81% from 5,33,401 hectares in 2011 to 5,91,108 hectares in 2024 due to climate change, the report said.

Also read | The Sikkim flood was one of Asia’s worst climate disasters in 2023

The rapid expansion of these lakes is attributed to accelerated melting of glaciers due to rising temperatures in the region, with potentially serious consequences for downstream communities, infrastructure and biodiversity, the report said.

Physically, the shrinking of mountain glaciers and the expansion of glacial lakes are among the most recognizable and dynamic consequences of climate warming in this environment, the report said.

“Therefore, under such a changing environment, close monitoring of the relative change in the water distribution area of ​​even smaller lakes in this region has become critical,” the report said.

The sudden and often catastrophic floods occur when glacial lakes breach their natural moraine dams, releasing large amounts of water downstream.

The CWC emphasized that the increased water spread from these lakes requires rigorous monitoring and urgent risk management strategies.

To overcome the challenges in monitoring these remote lakes, a senior official said, the CWC has used advanced satellite technology, especially the Sentinel-1 Synthetic Aperture Radar (SAR) and Sentinel-2 multispectral imagery that provides precise monitoring under all weather conditions allow.

“The high-resolution capabilities of these satellites allow CWC to detect changes in lake size with an accuracy of 10 meters, even in challenging conditions such as cloud cover. This monitoring technology is critical to providing timely updates on the condition of these high-risk lakes , enabling early interventions when necessary,” the official said.

Also read | The government will review the design of dams vulnerable to flooding from glacial lakes

The CWC report also underlined the transboundary risks associated with the expansion of glacial lakes in neighboring countries, including Bhutan, Nepal and China.

Given the interconnected nature of the river basins in the Himalayan basin, cooperation with these countries is crucial for managing the potential impact of GLOFs, the report pointed out.

The report called for joint monitoring efforts and data sharing to build a more comprehensive risk assessment and mitigation strategy.

It emphasized the urgent need for international and regional cooperation in developing early warning systems, improving disaster management plans and promoting community awareness initiatives to protect vulnerable populations.

Also read | Satellite images of the catchments of India’s Himalayan river basins show significant changes in glacial lakes

The implications of glacial lake areal expansion extend beyond flood risks and could impact water availability in the region’s major river systems, including the Ganga, Brahmaputra and Indus.

Using data from 2011 and comparisons with five- and 10-year averages, the CWC report identified patterns of glacial lake expansion that could help authorities designate areas of high risk.

The official quoted above said that with its commitment to reducing monitoring intervals and improving data precision, the CWC aims to establish a robust system for early detection and response to the evolving challenges posed by the Himalayan glacial lakes.