Melting of Glaciers: Causes & Impacts

Syllabus: GS3/Environment; Climate Change

Context

• Recent floods in Nepal following an ice-and-rock avalanche have renewed concerns over rapidly warming Himalayan glaciers, glacial-lake outbursts, and their implications for India’s water and economic security.

About Melting of Glaciers

• The Himalayas are the ecological mainstay of the Indian Subcontinent, as they shape the monsoon, sustain biodiversity and pilgrimage economies, and feed the Indus, Ganga and Brahmaputra systems.
• Glaciers act as natural water reservoirs, releasing meltwater particularly during dry periods.
• However, accelerating warming is causing glacier retreat. 
• Himalayan river basins may reach ‘Peak Water’ around mid-century, after which declining ice reserves can reduce long-term river flows. 
• The Hindu Kush Himalaya (HKH) could lose up to 80% of its present glacier volume by 2100.

India’s Vulnerability

• ‘A Resilient Himalaya: protecting a region at risk and securing future prosperity’ report (2024) estimates that ₹64.8 lakh crore, or 21.5% of India’s FY24 GDP, is dependent on the Himalayas.
  • It is not a projection of GDP loss; it measures economic activity dependent on Himalayan water.
  • Its three layers are:
    • Direct: GSDP of Himalayan states.
    • Indirect: downstream agriculture, manufacturing, hydropower and services dependent on Himalayan-fed rivers and groundwater recharge.
    • Induced: supply-chain and wage-spending effects.
  • The Himalayas occupy 18% of India’s land but account for around 35% of its disasters.

Key Reasons for Glacier Melting

• Global Warming: rising temperatures accelerate ice loss.
• Black Carbon: incomplete combustion deposits soot on snow, reducing albedo and increasing solar absorption. Recent modelling attributes about one-third of Himalayan glacier mass loss to South Asian black carbon.
  • Black carbon darkens snow, reducing reflectivity and increasing solar absorption.
• Local Anthropogenic Pressures: brick kilns, cookstoves, transport and crop-residue burning.
• Infrastructure & Land-use Change: roads, hydropower and tourism facilities increase exposure and vulnerability in unstable mountain terrain.

Why Glacier Retreat Matters?

• Glacier retreat represents both a slow economic drain and a sudden disaster risk.
  • The Nepal floods demonstrated how disturbances at high altitude can rapidly become downstream catastrophes.
  • The failure of the Bhote Koshi warning system to detect the sudden debris surge highlights the limits of existing monitoring.
• Black carbon offers a comparatively actionable intervention.
  • Zigzag brick kilns can reduce black-carbon and particulate emissions by roughly 70% and fuel use by 20–30%.
  • Punjab and Haryana have completed the transition, while Uttar Pradesh, India’s largest brick producer, has reached 56% adoption.

Impacts of Melting Glaciers

• Water Insecurity: eventual decline in glacier-fed river flows.
• Agriculture: risks to wheat and rice in the Indo-Gangetic Plain and tea in Assam and Bengal.
• Energy: implications for hydropower, particularly in the Northeast.
• Disasters: expanding glacial lakes can burst through unstable moraine dams, producing Glacial Lake Outburst Floods (GLOFs), flash floods, landslides, and avalanches.
• Macroeconomic stress: disasters disrupt supply chains, displace people and increase reconstruction costs, potentially intensifying fiscal and sovereign-debt pressures.
  • The South Lhonak Lake warning in Sikkim illustrates the challenge: a 2021 scientific study identified instability; the lake subsequently burst, killing at least 50 people.

Related Measures & Efforts

• National Mission for Sustaining the Himalayan Ecosystem (NMSHE) under India’s National Action Plan on Climate Change (NAPCC).
• Strengthening GLOF early-warning systems, glacier monitoring and hazard mapping.
• India-Nepal-China information sharing on Himalayan ecology and transboundary hazards.
• Climate pacts and technology-transfer mechanisms.
• International experience such as Switzerland’s 2025 Blatten glacier-collapse response, where advance monitoring and evacuation helped limit casualties.

Way Forward

• Adopt a Himalayan-wide, risk-informed development model: cumulative environmental assessments, mountain-specific construction standards, continuous glacier and lake monitoring, community-based evacuation systems, and transboundary data sharing.
• India should establish a targeted brickmaking transition fund, retire inefficient kilns, and simultaneously address kilns, cookstoves, transport, and crop-residue burning at the airshed scale.
• Thus, climate mitigation, disaster resilience and sustainable mountain development must proceed together.

Source: IE