Context:
The UNESCO report titled “Mountains and Glaciers: Water Towers”, released on the first World Day for Glaciers (March 21, 2025), highlights the rapid and largely irreversible impacts of global warming on mountain ecosystems.
Major Environmental Changes in Mountain Regions
Glacier Melting Accelerates
- The last three years recorded the largest glacial mass loss on record.
- Since 1975, glaciers (excluding Greenland and Antarctica) have lost over 9,000 billion tonnes of ice — equivalent to an ice block the size of Germany.
- Black carbon and other particulate matter deposits are accelerating melt rates by darkening ice surfaces and increasing solar absorption.
Permafrost Thaw Intensifies
- Permafrost (permanently frozen ground) is thawing rapidly in high-altitude regions.
- Melting permafrost releases organic carbon into the atmosphere, further fueling climate change.
- Thawing destabilizes rock slopes and debris-covered areas, increasing risks of landslides and other geological hazards.
Declining Snow Cover
- A study published in Nature (2024) shows a 7.79% global decline in persistent snow cover between 1979 and 2022.
- Snow cover loss is most prominent in spring and summer, impacting water availability.
Erratic Snowfall Patterns
- The snow-rain transition elevation is rising, causing lower elevations to receive more rain than snow.
- Snow melts earlier, disrupting traditional water flow cycles.
Increased Risk of Glacial Lake Outburst Floods (GLOFs)
- Melting glaciers and unstable permafrost heighten the risk of sudden, catastrophic floods from glacial lakes.
Why This Matters
Water Security Threatened
- Over 2 billion people downstream rely on mountain glaciers for freshwater.
- Water flows will become unpredictable, with shifts in timing, volume, and sediment load.
Rising Sea Levels
- Melted glacial ice accounts for 25–30% of observed global sea-level rise.
- Between 2006 and 2016, glaciers lost 335 billion tonnes of ice annually, contributing nearly 1 mm per year to sea-level rise.
- Every millimeter of sea-level rise can expose 300,000 people to annual flooding.
Policy Urgency
- Experts emphasize the need for immediate policy action, awareness programs, and resource mobilization to mitigate these impacts.
Global warming is drastically reshaping mountain regions, causing faster glacier melting, permafrost thaw, snow cover reduction, and erratic snowfall patterns. These changes endanger global water security, accelerate sea-level rise, and increase climate-related hazards. Immediate action and strong international policy frameworks are crucial to protect these fragile ecosystems and the billions who depend on them.
