Significant Rise Himalayan Glacial Lakes Increase 10.81% from 2011 to 2024

A recent government report indicates that glacial lakes and water bodies in the Himalayan region have experienced a 10.81% increase in area from 2011 to 2024, primarily driven by climate change. This expansion raises concerns about the heightened risk of glacial lake outburst floods (GLOFs). The report, accessed by PTI from the Central Water Commission (CWC), highlights that lakes in India have seen an even more significant growth, with a surface area increase of 33.7%.

Key Findings from the CWC Report

Expansion of Indian Lakes

• The total area of glacial lakes in India grew from 1,962 hectares in 2011 to 2,623 hectares in 2024, marking a 33.7% increase.
• A total of 67 lakes in India experienced over 40% increase in surface area, categorizing them as high-risk for GLOFs.

Regional Variations

• The most notable expansions were recorded in Ladakh, Himachal Pradesh, Uttarakhand, Sikkim, and Arunachal Pradesh.
• Overall, glacial lakes across the Himalayan region increased from 533,401 hectares in 2011 to 591,108 hectares in 2024.

Impacts of Climate Change

Melting Glaciers

• The rapid expansion of glacial lakes is attributed to the accelerated melting of glaciers due to rising temperatures, posing significant threats to downstream communities, infrastructure, and biodiversity.

Physical Changes

• The shrinking of mountain glaciers and expansion of glacial lakes are primary indicators of climate change in the Himalayan environment.

Risks Associated with GLOFs

• GLOFs (Glacial Lake Outburst Floods) occur when glacial lakes breach their natural moraine dams, leading to sudden and often catastrophic floods.
• The report emphasizes the urgent need for rigorous monitoring and risk management strategies to mitigate the impacts of GLOFs.

Technological Advancements in Monitoring

Satellite Technology 

The CWC has adopted advanced satellite technologies, such as,

• Sentinel-1 Synthetic Aperture Radar (SAR)
• Sentinel-2 Multispectral Imagery

Monitoring Capabilities 

• These technologies enable precise monitoring of lake sizes with 10-meter accuracy, even under challenging conditions like cloud cover.

Transboundary Risks

• The report identifies the transboundary risks posed by glacial lake expansions in neighboring countries, including Bhutan, Nepal, and China.
• Emphasizes the importance of collaboration for effective management of GLOFs, including data sharing and joint risk assessment strategies.

Recommendations for Risk Mitigation

• Development of robust early warning systems is essential for disaster preparedness.
• Promoting awareness among local populations is crucial to safeguard vulnerable communities.
• Improvement of disaster management plans through international and regional cooperation is vital for effective responses to potential GLOFs.

Implications for Water Availability

Impact on River Systems 

• The expansion of glacial lakes may affect water availability in major river systems such as the Ganga, Brahmaputra, and Indus.

Monitoring Patterns

• The CWC report utilized data comparisons from 2011 and five to ten-year averages to identify patterns of glacial lake expansion, allowing for targeted risk assessments.

About Glacial lakes/GLOF

• Glacial lakes are large bodies of water that sit in front of, on top of, or beneath a melting glacier.
• As a glacier withdraws, it leaves behind a depression that gets filled with meltwater, thereby forming a lake.
• The more the glacier recedes, the bigger and more dangerous the lake becomes. Such lakes are mostly dammed by unstable ice or sediment composed of loose rock and debris.
• In case the boundary around them breaks, huge amounts of water rush down the side of the mountains, which could cause flooding in the downstream areas. This is called the Glacial Lake Outburst Flood.

Reasons for GLOFs

• It can be triggered by various reasons, including glacial calving, where sizable ice chunks detach from the glacier into the lake, inducing sudden water displacement.
• Incidents such as avalanches or landslides can also impact the stability of the boundary around a glacial lake, leading to its failure, and the rapid discharge of water.