The accelerated melting of glaciers due to climate change poses a significant global threat, particularly to coastal and low-lying regions, including densely populated areas in India and other countries. Rising sea levels, driven by glacier melt and thermal expansion, endanger millions of lives, infrastructure, and ecosystems.
Indicators of Glacier Melting
1. Rising Sea Levels
Data Point: Global sea levels have risen by approximately 100 mm (10 cm) from 1993 to 2024.
Implication: Glacier melt, alongside thermal expansion, is a primary driver of this rise. Each millimeter of sea level rise exposes an additional 200,000 to 300,000 people to annual flooding globally.
Regional Example: The complete loss of Venezuela’s Humboldt Glacier in the Andes highlights the rapid retreat of glaciers, contributing to global sea level rise.
2. Accelerated Glacier Mass Loss
Global Scale: All 19 glacier regions worldwide experienced net mass loss in 2024 for the third consecutive year, with ice loss accelerating over the past decade.
Specific Cases:
Himalayas: Glaciers in the Hindu Kush Himalayan (HKH) region lost ice at a rate 65% faster in 2011–2020 compared to the previous decade. Projecting a 30–50% volume loss by 2100 under 1.5–2°C warming scenarios.
Antarctica: The Thwaites Glacier’s retreat could contribute up to 10 feet of sea level rise if it collapses entirely.
Tropics: Indonesia’s Eternity Glaciers may vanish by 2026, and Mount Kenya’s ice cover is now just 4.2% of its 1900 extent.
Black Carbon Impact: Soot from biomass burning and fossil fuels darkens snow, increasing heat absorption and accelerating melt in regions like the Himalayas.
3. Glacial Lake Formation and Outburst Floods
Trend: Over 110,000 glacial lakes have formed globally, with their number and size increasing since the 1990s due to glacier retreat.
Risk: These lakes pose risks of glacial lake outburst floods (GLOFs), which can devastate downstream communities. For example, a 2023 GLOF in Sikkim, India, killed at least 26 people and left 142 missing.
Himalayan Context: Project a threefold increase in GLOF risk in the Himalayas, endangering villages, roads, and hydropower infrastructure.
4. Temperature Anomalies
Global Warming: 2023 was the hottest year on record, with average temperatures 1.48°C above pre-industrial levels.
Regional Impact: The HKH region is warming faster than the global average, with projections of a 2.1°C increase even under Paris Agreement targets, potentially melting one-third of Himalayan glaciers by 2100.
Severity of the Issue
1. Sea Level Rise and Coastal Inundation
Current Impact: The 10 cm rise since 1993 already threatens low-lying areas. For instance, 250 million people in India live within 50 km of the coastline, facing increased flood risks.
Future Projections:
By 2100, global sea levels could rise 60–70 cm due to thermal expansion and glacier melt, with an additional meter possible by 2200 from Arctic, Antarctic, Himalayan, and Alpine glacier losses.
Cities like Mumbai, Kolkata, and Chennai, along with small island states like the Maldives and Tuvalu, face severe inundation risks. The Maldives, with most islands less than 2 meters above sea level, could become uninhabitable, potentially creating 300,000 climate refugees.
Economic and Social Toll: Flooding disrupts global supply chains (e.g., the 2011 Bangkok floods impacted computer manufacturing) and threatens infrastructure like nuclear power plants and agricultural lands.
2. Water Supply Disruptions
Short-Term: Increased glacier melt temporarily boosts river flows, benefiting agriculture in regions like the Indus and Ganges basins.
Long-Term: Post-mid-century, declining glacier volumes will reduce water availability, threatening food security for nearly 2 billion people in South Asia.
Case Study: The Ganges, vital for 500 million people, has seen its source glacier (Gangotri) shrink by 1.7 km in 90 years, impacting irrigation and domestic water supplies.
3. Ecosystem and Biodiversity Loss
Threatened Species: Melting glaciers and snow loss endanger species like the snow leopard and tiger in the Himalayas.
Ecosystem Shifts: Thawing permafrost and reduced snow cover expose plants to harsh conditions, potentially leading to ecosystem collapse in high-altitude regions.
4. Increased Natural Disasters
GLOFs and Landslides: The 2021 Uttarakhand glacier collapse triggered floods that destroyed hydropower projects and killed dozens.
Permafrost Thaw: Thawing permafrost destabilizes mountain slopes, increasing landslide risks across the Himalayas, Andes, and Alps.
Deterioration Timeline
Short-Term (2025–2035)
Glacier Loss: Tropical glaciers, like Indonesia’s Eternity Glaciers, may disappear by 2026. Himalayan glaciers could lose 10–20% of their volume.
Sea Level Rise: Continued rise of 3–4 mm per year, adding 3–4 cm by 2035.
Risks: Increased frequency of GLOFs and flash floods, particularly in the Himalayas, Andes, and Alps. Coastal flooding will intensify in cities like Mumbai and Dhaka.
Example: The 2023 Sikkim GLOF underscores the immediate threat to Himalayan communities.
Medium-Term (2035–2100)
Glacier Loss: Himalayan glaciers may lose 30–50% of their volume by 2100 under 1.5–2°C warming, with up to 80% loss possible under higher emissions scenarios.
Sea Level Rise: Projected rise of 60–70 cm by 2100, with significant contributions from Antarctic and Greenland glaciers.
Risks:
Reduced water availability in major river basins (Ganges, Indus, Brahmaputra) after peak melt around mid-century, leading to drought and food insecurity.
Coastal cities face regular inundation, displacing millions. For example, Bangladesh’s low-lying areas could see 100 million people affected.
Infrastructure Impact: Hydropower projects in the Himalayas and Andes may become economically unviable due to reduced water flows.
Long-Term (2100–2200)
Glacier Loss: Near-total loss of smaller glaciers (e.g., in the Alps and Andes) and significant retreat of polar glaciers.
Sea Level Rise: An additional meter possible by 2200, with catastrophic impacts from Thwaites Glacier collapse (up to 10 feet).
Risks:
Mass displacement of coastal populations, potentially affecting 1 billion people globally.
Collapse of agriculture in South Asia due to water scarcity.
Irreversible ecosystem changes, with extinction risks for high-altitude species.
Impacts on Populated Areas
1. Coastal Cities in India and Beyond
India: Cities like Mumbai, Kolkata, and Chennai, with populations exceeding 30 million combined, face severe flooding risks. Mumbai’s proximity to the Arabian Sea and Kolkata’s location in the Ganges delta make them particularly vulnerable.
Global Examples:
Maldives: Most islands are less than 2 meters above sea level, risking complete submersion and displacement of 300,000 people.
Tuvalu: Half of its 10,000 residents live within 3 meters of sea level, facing potential migration.
Bangladesh: 100 million people in low-lying areas are at risk of flooding, threatening food security and infrastructure.
Economic Impact: Flooding disrupts global supply chains, as seen in the 2011 Bangkok floods, and threatens critical infrastructure like ports and power plants.
2. Himalayan Communities
Water Scarcity: Post-mid-century, reduced glacier melt will limit water for irrigation, affecting farmers in the Indus and Ganges basins.
GLOF Risks: Communities in Uttarakhand, Sikkim, and Nepal face increasing threats from GLOFs, as seen in the 2021 Uttarakhand disaster and 2023 Sikkim floods.
Displacement: Villages, are already seeing migration due to unpredictable water flows and erosion.
3. Global Coastal Megacities
New York City: Particularly vulnerable to Greenland’s Northeast Ice Stream and Petermann Glacier, which could contribute 2–3 inches of sea level rise over 200 years.
Miami and Rio de Janeiro: These cities face higher-than-average sea level rise due to gravitational effects from Greenland and Antarctic melt.
Huaraz, Peru: A glacial lake outburst flood from Laguna Palcacocha could threaten 35,000 lives, given its 14-fold size increase since 1941.
Recommendations
Reduce Carbon Emissions:
Urgent global action to meet Paris Agreement targets (1.5–2°C warming limit) can reduce glacier loss to 25% by 2100, compared to 50% under current trajectories.
Transition from coal and biomass burning to cleaner energy sources to reduce black carbon pollution.
Enhance Early Warning Systems:
Develop and deploy GLOF early warning systems in high-risk areas like the Himalayas and Andes.
Expand observation networks and data-sharing agreements across the HKH region to predict disasters.
Ecosystem-Based Adaptation:
Restore forests and shrubs on mountain slopes to prevent floods and landslides, as seen in Nepal’s EbA South project.
Protect local springs and streams to maintain water supplies for semi-arid mountain communities.
Infrastructure Resilience:
Reassess hydropower projects in glacial regions to account for reduced water flows post-mid-century.
Build flood diversion structures, such as gabions, to protect villages and infrastructure from GLOFs.
Community Preparedness:
Educate and relocate communities in high-risk zones, particularly near glacial lakes and coastal areas.
Support farmers with drought-resistant crops and alternative livelihoods to adapt to changing water availability.
The rapid melting of glaciers is a clear indicator of climate change, with severe implications for sea level rise, water security, and natural disasters. Coastal cities like Mumbai and low-lying nations like the Maldives face existential threats, while Himalayan communities risk floods and water scarcity. Immediate action to reduce emissions, enhance early warning systems, and implement ecosystem-based adaptation is critical to mitigate these risks. For TheBrink readers, understanding the timeline and scale of this crisis underscores the urgency of collective global action to protect vulnerable populations and ecosystems.
-Chetan Desai (chedesai@gmail.com)
