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Source: Education

Context

According to a study published in the journal Nature Geoscience, 99% of the world's glaciers disintegrate at rates ranging from 0.02 to 2.68 mm per year. Researchers employed machine learning to estimate erosion rates for over 180,000 glaciers, emphasizing the importance of precipitation, elevation, and geology.

About Glaciers 

Definition & Origin

• Glacier: A huge mass of ice that moves slowly over land.
  
  
• Derived from the French word “glace” meaning ice.
  
  
• Often referred to as “rivers of ice” due to their slow but steady movement.

Factors Influencing Glacier Erosion

• Traditional assumption challenged:
  
  
• Glacial velocity alone is not the most important predictor of erosion.
  
  
• Key controlling variables identified:
  
  
• Precipitation (Mean Annual Precipitation - MAP) — most dominant influence across all glacier types.
  
  
• Glacial elevation, length, latitude, and underlying geology also strongly affect erosion rates.
  
  
• Mean Annual Air Temperature (MAAT) influences erosion but less than precipitation.
  
  
• Importance of seismicity, lithology, and geothermal heat flux (GHF) in controlling erosion emphasized.
  
  
• Complex interaction:
  
  
• Erosion is influenced by a combination of temperature, subglacial water presence, rock type, and geothermal heat.

Shape & Structure

• Typically tongue-shaped, broadest at the source and narrower downhill.
  
  
• Movement occurs despite being solid ice, due to pressure from accumulated snow above.

Movement Characteristics

• Rate of movement is greatest in the middle due to less obstruction.
  
  
• Sides & bottom are slowed by friction from valley sides & floors.
  
  
• If stakes are planted across a glacier in a straight line, they form a curved shape downhill, showing the center moves faster than the sides.

Glacial Landforms

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Source: Antarctic Glaciers

• Glacial landforms can exist even where there are no active glaciers today (relict features from past glaciation).
  
  
• Examples: U-shaped valleys, moraines, cirques, drumlins.
  

Types of Glaciers

1. Alpine Glaciers – Found in mountainous regions, confined to valleys.
   
   
2. Ice Sheets – Massive, continental-scale glaciers covering large areas (e.g., Antarctica, Greenland).

Glacial Cycle of Erosion

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Source: Researchgate

The glacial cycle of erosion explains the transformation of a mountain landscape under the action of moving ice over time. It is divided into three stages: Youth, Maturity, and Old Age.

Youth Stage

• Dominant Process: Inward cutting activity of ice in a cirque.
  
  
• Landforms Developing:
  
  
• Formation of aretes (sharp ridges).
  
  
• Emergence of horns (pyramidal peaks).
  
  
• Valley Characteristics:
  
  
• Hanging valleys not prominent at this stage.
  
  
• Valleys are narrow and steep-sided.

Maturity Stage

• Transformation of Glacier:
  
  
• Valley glacier becomes a trunk glacier.
  
  
• Landform Development:
  
  
• Hanging valleys start emerging.
  
  
• Opposite cirques come closer.
  
  
• Valley Profile:
  
  
• Glacial trough acquires a stepped profile.
  
  
• Profile becomes regular and graded due to continued erosion.
  

Old Age Stage

• Valley Shape:
  
  
• Formation of a distinct U-shaped valley.
  
  
• Fluvial-Glacial Features:
  
  
• Development of outwash plains with depositional features such as:
  
  
• Eskers
  
  
• Kame terraces
  
  
• Drumlins
  
  
• Kettle holes
  
  
• Summit Changes:
  
  
• Opposite cirques coalesce.
  
  
• Summit heights greatly reduced.
  
  
• Mountain tops become rounded.

Current Scenario of Climate Change

• Climate change is a global crisis marked by rising temperatures, changing precipitation patterns, and extreme weather events, driven primarily by increased greenhouse gas (GHG) emissions.
  
  
• According to the IPCC Sixth Assessment Report (2023), global surface temperature has risen by approximately 1.1°C above pre-industrial levels, with catastrophic impacts already evident worldwide.
  
  
• The Emissions Gap Report 2024 warns that current national pledges fall short of limiting warming to 1.5°C, forecasting a probable increase of 2.8°C by 2100 without urgent action.
  
  
• The World Meteorological Organization’s State of the Climate Report (2024) highlights unprecedented climate extremes, including heatwaves, floods, and droughts, stressing the urgency for mitigation.
  
  
• The World Energy Outlook 2024 emphasizes the continued dependence on fossil fuels, slowing progress in decarbonization, and calls for accelerated clean energy adoption.
  
  
• Regionally, the Assessment of Climate Change over Indian Region (ACCAR) documents increased frequency of heatwaves, erratic monsoons, and vulnerability of key ecosystems, stressing the need for climate resilience in India.

Reasons for the Melting of Glaciers

Global Warming

• Rising temperatures lead to glaciers melting faster than they can accumulate new snow.
  
  
• Direct result of increasing greenhouse gas (GHG) concentrations in the atmosphere.
  

Human Activities

• Deforestation, burning of fossil fuels, and industrial processes emit large amounts of GHGs.
  
  
• Intensifies climate change, accelerating glacier retreat.
  

Changes in Precipitation

• Altered amount, timing, and form (snow vs. rain) of precipitation impacts glacier mass balance.
  
  
• Reduced snowfall means less replenishment.
  

Natural Factors

• Volcanic activity can alter atmospheric composition and temperatures.
  
  
• Changes in solar radiation affect long-term ice accumulation and melting patterns.

Impact of Melting Glaciers on Climate Change & Human Life

Rising Sea Levels

• Glacial meltwater contributes to sea level rise.
  
  
• Threatens coastal communities, infrastructure, and low-lying islands.
  

Water Scarcity

• Glaciers act as freshwater reservoirs for millions.
  
  
• Retreating glaciers reduce water availability, impacting agriculture and industries.
  

Changes in Weather Patterns

• Freshwater influx alters ocean salinity, weakening the Atlantic Meridional Overturning Circulation (AMOC).
  
  
• Causes cooler temperatures in Europe and increased hurricane activity in the North Atlantic.
  

Ecosystem Disruption

• Loss of glacier-fed rivers affects biodiversity and food webs.
  
  
• Changes in species distribution and habitat availability.
  

Potential for Natural Disasters

• Glacier retreat increases risks of flash floods, glacial lake outburst floods (GLOFs), and landslides.
  

Reduced Albedo Effect

• Ice surfaces reflect sunlight; glacier loss exposes darker surfaces, increasing solar absorption and warming.

Impact of Climate Change on Glaciers

• Glaciers act as sensitive indicators of climate change due to their direct response to temperature and precipitation variations.
  
  
• The State of the Cryosphere Report (2024) reveals accelerated ice loss in mountain glaciers worldwide, with implications for sea level rise and freshwater availability.
  
  
• The World Glacier Monitoring Service (WGMS) Annual Report (2024) confirms ongoing global glacier retreat, with many glaciers losing significant mass and volume annually.
  
  
• In the Himalayas, often called the “Third Pole,” studies show that glaciers could lose up to 80% of their volume by 2100 if global warming continues unabated, threatening water security for millions.
  
  
• Glacial retreat leads to increased formation of glacial lakes, heightening risks of Glacial Lake Outburst Floods (GLOFs), which endanger downstream communities and infrastructure.
  
  
• Changes in glacier-fed river systems disrupt biodiversity, agriculture, hydropower generation, and drinking water supplies across South and Central Asia.
  
  
• The melting cryosphere contributes to global sea level rise, exacerbating coastal erosion and flooding worldwide.
  
  
• Feedback loops such as reduced albedo (reflectivity) accelerate warming, as exposed land and water absorb more heat compared to reflective ice surfaces.

Global Glacial Retreat

• Polar Regions: In polar regions, the melting of glaciers is contributing to rising sea levels. The World Meteorological Organization's State of the Climate Report highlights that the Arctic is warming at more than twice the global average, leading to accelerated ice melt.
  
  
• Global Glacier Mass Loss: A study published in Science estimates that nearly 40% of the world's glaciers are already committed to melting due to past and current climate-heating emissions. If global temperatures increase by 2.7°C, this could rise to 75%, significantly impacting sea levels and ecosystems.

Strategies to Reduce Glacier Melting

Reduce Carbon Emissions

• Shift to renewable energy sources like wind and solar.
  
  
• Net zero emission targets implementation.
  

Promote Energy Efficiency

• Building insulation and energy-efficient appliances (e.g., Green Housing Scheme – National Housing Bank).
  

Encourage Public Transportation

• Reduce reliance on private vehicles.
  
  
• Example: Public Transport Fare Subsidy Scheme – Hong Kong.
  

Afforestation & Reforestation

• Tree plantation as a carbon sink.
  
  
• Reduce atmospheric CO₂ levels.
  

Reduce Waste & Promote Recycling

• Limit GHG emissions from landfills and waste disposal.
  

Prevent Deforestation

• Preserve natural carbon sinks (e.g., REDD+ Initiative).
  

Sustainable Agriculture Practices

• Conservation tillage, water-efficient irrigation to reduce emissions.
  

International Agreements

• Paris Agreement, Montreal Protocol, and other global pacts for emission reduction.
  

Adaptation Measures

• Flood management, water resource planning, and infrastructure protection in glacier-fed regions.
  

Source: DOWN TO EARTH