Subject: Physical Geography

The cryosphere, Earth's frozen realm encompassing ice sheets, glaciers, permafrost, and sea ice, plays a pivotal role in regulating global climate through complex feedback mechanisms and interactions with other Earth systems.

Direct Climate Regulation Mechanisms

• Albedo Effect:

  • The cryosphere's white surfaces reflect up to 90% of solar radiation back into space.
  • Recent data shows significant albedo changes between 2023-2025 due to ice melt, creating a positive feedback loop of warming.
  • Loss of reflective surfaces leads to increased solar energy absorption by darker ocean waters and land surfaces.

• Heat Exchange and Distribution:

  • Acts as Earth's natural thermoregulator through ice-ocean interactions.
  • Sea ice formation and melting influence global ocean circulation patterns.
  • Controls heat distribution between polar and equatorial regions.

Impact on Global Systems

• Sea Level Rise:

  • Between 2000-2023, glaciers lost 6,542 billion tonnes of ice.
  • Contributing 18mm to global sea-level rise.
  • Annual ice loss averages 273 billion tonnes, causing 0.75mm yearly sea-level rise.

• Ocean Circulation:

  • Influences thermohaline circulation through freshwater input.
  • Affects global weather patterns and marine ecosystems.
  • Regulates ocean salinity and density gradients.

Regional Manifestations

• Arctic Changes:

  • March 2025 recorded lowest winter peak extent at 14.33 million square kilometers.
  • 1.31 million square kilometers below the 1981-2010 average.
  • Impacts on Northern Hemisphere weather patterns.

• Himalayan Glacier Status:

  • Gepang Gath glacier shows negative mass balance of −0.90 ± 0.30 m w.e. a−1.
  • Karakoram region exhibits relative stability at -0.04 ± 0.09 m.w.e./yr.
  • Varying rates of mass loss across different regions.

The cryosphere's role in climate regulation highlights the critical need for implementing Paris Agreement targets and strengthening global climate action through initiatives like the Cryosphere Monitoring Programme (CMP) and Global Cryosphere Watch (GCW).