THE CONTEXT: Mountains, covering 33 million sq km of Earth’s surface, are vital for sustaining life, supporting freshwater resources for around 2 billion people downstream. However, soaring global temperatures are causing rapid and largely irreversible changes in mountain ecosystems, as highlighted in the UNESCO report The United Nations World Water Development Report 2025 – Mountains and Glaciers: Water Towers. These changes have far-reaching implications for water resources, biodiversity, and human safety.
KEY CHANGES IN MOUNTAIN ECOSYSTEMS:
1. Glacier Melting
Extent and Accelerated Loss
-
- Cumulative Impact: Since 1975, glaciers (excluding Greenland and Antarctica) have lost over 9,000 billion tonnes of mass, equivalent to an ice block the size of Germany with a thickness of 25 meters. This trend is captured in the WGMS data showing a steep decline in glacier mass globally1.
- Recent Trends: The last three years recorded unprecedented glacial mass loss, with 450 gigatons lost in 2024 alone, marking the highest annual loss on record.
- Regional Vulnerability: Scandinavia, Svalbard (Norwegian archipelago), and North Asia are among the regions witnessing the largest annual losses.
Contributing Factors
-
- Anthropogenic Climate Change: Rising global temperatures due to greenhouse gas emissions are the primary driver of accelerated glacier melting.
- Black Carbon Deposition: Increased wildfires and dust storms deposit particulate matter on glaciers, darkening their surfaces. This enhances solar radiation absorption, accelerating melting rates during high solar radiation periods.
- Feedback Loops: Melting glaciers reduce albedo (reflectivity), further intensifying warming.
Implications
-
- Water Resources: Glaciers act as natural water towers for downstream populations. Their rapid melting disrupts seasonal water availability and increases variability in flow.
- Sea-Level Rise: Melted glacier ice contributes 25–30% to global sea-level rise. Between 2006–2016, glaciers lost an average of 335 billion tonnes annually, causing a sea-level rise of nearly 1 mm per year1. Such changes threaten coastal communities globally.
2. Accelerating Permafrost Thaw
Definition and Trends
Permafrost refers to ground that remains frozen at or below 0°C for at least two consecutive years. Rising temperatures are causing rapid thawing, destabilizing mountain ecosystems.
Impact of Thawing
-
- Carbon Release: Thawing permafrost releases vast amounts of organic carbon into the atmosphere, exacerbating climate change through increased greenhouse gas emissions.
- Ecosystem Instability:
- Destabilization of rock slopes and moraines increases risks of landslides and erosion.
- Debris-covered slopes become vulnerable to collapse, threatening infrastructure and human settlements.
Global Carbon Reservoir
Mountain permafrost contains approximately 4.5% of global soil organic carbon, highlighting its significance as a climate regulator.
Case Study
The thawing permafrost in the Himalayas has led to frequent landslides and flash floods, disrupting local communities and infrastructure development projects.
3. Decline in Snow Cover
Trends
Snow cover has reduced significantly across mountain regions globally, particularly during spring and summer seasons. Persistent snow cover declined by approximately 7.79% between 1979 and 20221.
Future Projections
Climate models predict further reductions in snow cover due to rising temperatures and erratic precipitation patterns.
Implications
-
- Hydrological Cycles: Reduced snow cover impacts water storage capacity in mountain regions, leading to irregular water flows downstream.
- Biodiversity Loss: Snow-dependent species face habitat loss, threatening ecological balance in mountain ecosystems.
Example
The Alps have witnessed a significant decline in snow cover depth over recent decades, impacting winter tourism economies and freshwater availability.
4. Erratic Snowfall Patterns
Shifting Elevation
Atmospheric warming is causing the elevation at which rainfall transitions to snowfall to shift upwards. Lower elevations are experiencing reduced snow cover depth and shorter durations.
Consequences
-
- Increased precipitation falls as rain rather than snow.
- Earlier snowmelt disrupts agricultural cycles dependent on predictable water flows.
- Shrinking snow-covered areas reduce the albedo effect, intensifying warming trends locally.
Case Study
In the Andes Mountains, erratic snowfall patterns have led to reduced snowpack levels, impacting water availability for agriculture and hydropower generation downstream.
SIGNIFICANCE OF THESE CHANGES
1. Impacts on Water Resources
-
- Melting glaciers contribute significantly to global freshwater supplies. However, continued melting will make water flows more erratic and unpredictable.
- Changes in timing and volume of water flows will affect water availability downstream, impacting agriculture, drinking water supply, and hydropower generation.
2. Contribution to Sea-Level Rise
-
- Melted glacier ice accounts for 25–30% of the observed increase in global sea levels.
- Between 2006–2016, glaciers lost an average of 335 billion tonnes annually, contributing nearly 1 mm per year to sea-level rise. A single millimeter rise can expose up to 300,000 people to annual flooding.
3. Increased Risk of Glacial Lake Outburst Floods (GLOFs)
-
- Thawing glaciers create unstable glacial lakes held by natural dams made of ice or moraines.
- GLOFs have caused over 12,000 deaths in the past two centuries and significant damage to infrastructure such as roads, bridges, and hydropower plants.
4. Exacerbation of Climate Change
-
- Thawing permafrost releases organic carbon into the atmosphere, acting as a feedback loop that intensifies global warming.
THE WAY FORWARD:
Strengthening Climate Mitigation Measures
-
- Reduce Greenhouse Gas Emissions: Immediate and ambitious action is needed to stabilize global temperatures. This includes transitioning to renewable energy sources and implementing carbon pricing mechanisms.
- Global Cooperation: Strengthen international agreements such as the Paris Agreement to ensure collective efforts in reducing emissions.
- Adopt Geoengineering Solutions: Innovative techniques like covering glaciers with insulating blankets (e.g., Rhône Glacier project in Switzerland) and creating artificial glaciers (e.g., Ice Stupas in Ladakh) can slow down ice loss.
Enhancing Disaster Risk Reduction Mechanisms
-
- Early Warning Systems: Develop advanced monitoring systems for hazards like Glacial Lake Outburst Floods (GLOFs) and landslides caused by permafrost thaw.
- Infrastructure Resilience: Relocate vulnerable infrastructure and strengthen buildings using techniques like thermosyphons and passive cooling systems (e.g., SolarFrost project in Switzerland).
Promoting Sustainable Development Practices
-
- Afforestation Campaigns: Replenish mountain forests to counter soil erosion and restore biodiversity.
- Regulate Industrial Activities: Enforce strict regulations on mining and other harmful activities near glaciers and permafrost zones.
- Integrated Water Resource Management: Optimize water usage downstream by accounting for erratic flows from melting glaciers.
Empowering Local Communities
-
- Capacity Building: Provide resources, education, and decision-making authority to local communities for conservation efforts.
- Traditional Knowledge Integration: Combine indigenous practices with scientific insights for holistic ecosystem management.
- Food Security Initiatives: Address food insecurity among mountain communities through sustainable agriculture programs.
Advancing Scientific Research and Monitoring
-
- Cryosphere Monitoring Networks: Expand research on glacier mass balance, snow cover trends, and permafrost stability using satellite data (e.g., ERA5L reanalysis).
- Predictive Models: Develop climate models to forecast future impacts of warming on mountain ecosystems.
- Data Sharing Platforms: Facilitate global collaboration among scientists for sharing research findings.
THE CONCLUSION:
The accelerating loss of glacier mass and erratic cryospheric changes demand urgent global action to mitigate climate change, strengthen disaster resilience, and ensure sustainable management of mountain ecosystems. By integrating scientific innovation, community empowerment, and robust policy frameworks, humanity can safeguard these vital “water towers” for future generations while addressing their cascading impacts on biodiversity, freshwater resources, and global sea levels.
UPSC PAST YEAR QUESTION:
Q. How do the melting of the Arctic ice and glaciers of the Antarctic differently affect the weather patterns and human activities on the Earth? Explain. 2021
MAINS PRACTICE QUESTION:
Q. Discuss the impact of glacier melting on global sea levels and the hydrological cycle. Illustrate your answer with relevant examples.
SOURCE:
Spread the Word