Rapid Expansion of Himalayan Glacial Lakes | 11 Dec 2024

Source: TH

Why in News? 

The National Green Tribunal (NGT), taking suo motu cognisance of a news report, has recently issued a notice to the central government regarding the alarming increase in Himalayan glacial lakes, which have expanded by approximately 10.81% over the past 13 years due to rising temperatures.  

What are Glacial Lakes?  

• About: A glacial lake is a water body formed from a glacier, usually located at its base, but it can also develop on, within, or beneath the glacier. 
• Formation: Glacial lakes form when glaciers erode the land, creating depressions that fill with meltwater as the glacier retreats. 
  • Natural dams, made of ice or moraines, can also form glacial lakes, but these dams can be unstable and prone to bursting, leading to potential flooding. 
• Glacial Lake Expansion: The NGT highlighted the report’s finding that the surface area of glacial lakes in India has increased by 33.7% from 2011 to 2024, with 67 lakes identified as high-risk for GLOFs (glacial lake outburst floods). 
  • This poses a significant threat to infrastructure and human lives in regions like Ladakh, Himachal Pradesh, Uttarakhand, Sikkim, and Arunachal Pradesh. 
• Causes of Glacial Lake Expansion: 
  • Global warming is raising temperatures in the Himalayas, which accelerates glacier melting. 
  • Retreating glaciers contribute water to lakes and expose new land surfaces, facilitating the formation of new glacial lakes. 
  • Thawing permafrost creates water-collecting depressions, expanding glacial lakes as it loses its natural drainage barrier. 

What are the Concerns of the Rapid Expansion of Glacial Lakes in the Himalayas? 

• Impact on Downstream Communities: Communities downstream face displacement, loss of life, and property damage, with agriculture severely affected by floods. 
  • Many high-risk lakes lack monitoring and early warning systems, leaving communities unprepared.  
  • The NGT highlighted this issue for 67 lakes in Ladakh, Himachal Pradesh, and Uttarakhand, pointing to weak enforcement of disaster preparedness laws. 
• Feedback Loop: Rising global temperatures accelerate glacial retreat, expanding glacial lakes and increasing risks.  
  • The IPCC’s 6th Assessment Report highlights the unprecedented rate of Himalayan glacier retreat, worsening climate-induced hazards. 
• Infrastructure Vulnerability: Critical infrastructure like roads, bridges, and hydropower plants are vulnerable to GLOF-induced floods, causing significant damage, economic losses, and delays in development. 
• Ecosystem and Biodiversity Disruption: Floods from glacial lakes alter sedimentation and water flows, impacting aquatic biodiversity and disrupting habitats, as seen in the 2023 Sikkim floods affecting downstream river ecosystems. 
• Triggering Secondary Disasters: The destabilization of slopes due to melting ice and increased water pressure can trigger landslides. Apart from GLOFs and landslides, the rapid expansion of glacial lakes can also lead to: 
  • Debris Flows: As glaciers retreat, they expose loose material that can be mobilized during heavy rainfall or seismic activity, causing debris flows that threaten settlements. 
  • Erosion: Increased water levels in glacial lakes can accelerate bank erosion, leading to habitat destruction and loss of arable land. 
• Climate Change Impact: The increase in glacial lakes is directly linked to climate change, particularly rising temperatures leading to accelerated glacier melting.  
  • The Himalayan glaciers, crucial for rivers like the Yangtze and Ganges, support over a billion people, highlighting significant environmental changes affecting water resources and ecosystems. 

What Risk Mitigation Strategies can be Adopted to Address Glacial Lake Expansion? 

• Enhanced Monitoring Systems: Establishing comprehensive monitoring systems for glacial lakes is crucial. This includes satellite surveillance and ground-based assessments to track changes in lake volume and surface area, enabling timely responses to emerging threats. 
  • Promoting use of Synthetic-Aperture Radar imagery (a form of radar that is used to create two-dimensional images) to automatically detect changes in water bodies, including new lake formations, during the monsoon months. 
• Early Warning Mechanisms: Developing early warning systems for GLOFs can significantly reduce disaster risks. These systems should integrate meteorological data with hydrological models to predict potential outburst events and communicate risks effectively to local communities. 
• Transboundary Water Management: Given that many Himalayan rivers cross national borders, international cooperation is essential for effective management of water resources affected by glacial changes.  
  • Collaborative frameworks can help share data, best practices, and resources among neighboring countries. 
• Funding and Resource Mobilisation: Engaging with international organizations for funding can support infrastructure development aimed at mitigating disaster risks associated with glacial lake expansion.  
  • This includes investments in resilient infrastructure and sustainable practices that align with global climate goals. One such example is  Coalition for Disaster Resilient Infrastructure (CDRI). 
• Training Local Manpower: Apart from pressing specialised forces such as National Disaster Response Force (NDRF), the NDMA emphasises the need for trained local manpower.