Mains Practice Questions

Introduction :

The cryosphere consists of Earth’s frozen elements such as glaciers, snow cover, and ice caps. The Himalayan glaciers, known as the “Third Pole”, store the largest ice reserves outside the poles and feed major rivers like the Indus, Ganga, and Brahmaputra. Rapid glacier retreat due to climate change is disrupting river flows, increasing disaster risks, and threatening India’s long-term water security.

Body:

Impact on River Systems

• Altered river flow patterns: In the short term, glacier melt increases river discharge, causing higher summer flows.
  • Over the long term, continued retreat reduces glacier mass, leading to declining base flows, especially during dry seasons.
  • Studies by ICIMOD indicate that many Himalayan basins may see peak water availability by mid-century, followed by decline.
• Seasonal imbalance in water availability: Glacier-fed rivers traditionally ensured perennial flow. Reduced snow and ice storage weakens this buffering capacity, making rivers more rainfall-dependent and erratic.
• Increased Sediment Load and Channel Instability: As glaciers retreat, they leave behind vast amounts of loose debris (moraines).
  • Accelerated melting flushes this sediment into river systems, leading to siltation of riverbeds.
  • This reduces the water-carrying capacity of rivers, causing frequent shifting of river courses (braiding) and increasing the risk of breach in downstream embankments.

Increased Disaster Risks

• Glacial Lake Outburst Floods (GLOFs): Retreating glaciers form unstable glacial lakes dammed by loose moraines.Sudden breach causes catastrophic floods downstream.
  • Example: The 2021 Chamoli disaster in Uttarakhand and GLOF in Sikkim in 2023 highlighted the role of glacier collapse and meltwater in triggering flash floods.
• Higher frequency of flash floods and landslides: Enhanced meltwater combined with intense rainfall increases slope instability.
  • Himalayan states like Himachal Pradesh, Uttarakhand, and Sikkim have seen rising incidences of cloudbursts and landslides.
• Permafrost Thawing and Structural Instability: The thawing of permafrost (frozen ground) at higher altitudes acts as a "glue" for mountain slopes. Its degradation leads to rockfalls and massive landslides, even in areas without high rainfall, endangering high-altitude infrastructure and trekking routes.
  • Frequent rockfalls in the high-altitude reaches of Lahaul-Spiti regions are often linked to warming-induced slope destabilization.
• Threat to infrastructure: Roads, hydropower projects, and settlements in fragile mountain terrain face rising risk due to cryospheric instability.

Implications for Long-Term Water Security

• Stress on drinking water and irrigation: Around 600 million people depend directly or indirectly on Himalayan river systems.
  • Reduced long-term glacier contribution threatens urban water supply and irrigation in northern India.
• Impact on food security: Agriculture in the Indo-Gangetic plains relies on sustained river flows. Variability in water availability may reduce crop productivity and increase dependence on groundwater.
• Hydropower uncertainty: Short-term surge in flows may boost generation, but long-term decline and sediment load reduce project viability and safety.
• Transboundary water concerns: Himalayan rivers are transnational. Altered flows may intensify India’s water diplomacy challenges with neighbouring countries.

Measures to Minimize the Impact:

• Strengthen glacier monitoring & research through satellite mapping, mass-balance studies, and institutions like ISRO and ICIMOD to generate real-time cryosphere data.
• Develop early warning systems for glacial lake outburst floods (GLOFs), avalanches, and flash floods, especially in vulnerable Himalayan states.
• Promote climate-resilient infrastructure by regulating hydropower and road projects using carrying-capacity and hazard-zone assessments.
• Adopt integrated river basin management to balance upstream–downstream water needs and reduce seasonal water stress.
• Enhance water-use efficiency through micro-irrigation, rainwater harvesting, and demand-side management in glacier-fed basins.
• Strengthen regional cooperation on transboundary rivers for data sharing, disaster preparedness, and long-term water security.

Conclusion :

The retreat of Himalayan glaciers is transforming river systems from stable to highly variable ones, thereby intensifying disaster risks and weakening long-term water security. Addressing this challenge requires integrated mountain governance, robust glacier monitoring, early-warning systems for GLOFs, climate-resilient infrastructure, and sustainable water management. Strengthening adaptation strategies today is essential to safeguard India’s ecological balance, livelihoods, and future water security