Himalayan Snow Decline Threatens Major River Basins

Himalayan Snow Decline Threatens Major River Basins

Why in News ?

A new ICIMOD report highlights alarming snow persistence decline across the Hindu Kush Himalayas, risking reduced water flow in the Ganga, Indus, and Brahmaputra basins. This threatens water security, agriculture, hydropower, and livelihoods for nearly two billion people.

Himalayan Snow Decline Threatens Major River Basins

About the Sharp Decline in Snow Persistence:

  • ICIMOD’s recent study shows a significant fall in snow persistence across the Hindu Kush Himalayas (HKH).
  • The Ganga basin’s snow cover hit a two-decade low of 23.6% during early melt season.
  • The Indus basin snow persistence fell to 5% below normal, a sharp decline from past highs.
  • This is the third consecutive year of below-normal snow cover in the region.

Risks to Water Security and Livelihoods

  • Snowmelt from the HKH feeds major rivers — Ganga, Indus, and Brahmaputra — essential for agriculture, hydropower, and ecosystems.
  • Around 25% of river runoff depends on snowmelt, which is now alarmingly inconsistent.
  • The decline poses a grave threat to nearly two billion people across 12 major river basins.

Need for Policy Shift and Cooperation

  • ICIMOD stressed the urgency for science-based policies and regional cooperation on transboundary water management.
  • Experts urge emission mitigation and adaptive planning to address the changing snowfall and melt patterns.
  • Without action, water scarcity, food insecurity, and energy shortages could worsen across South Asia.

What is Snow Persistence?

●      Definition:
 Snow persistence refers to the time snow remains on the ground before melting, contributing vital water to people and ecosystems.

●      Significance in HKH River Basins:

○       Snowmelt supplies 23% of annual runoff across 12 major river basins.

○       Supports one-fourth of the world’s population and 240 million people in HKH directly.

○       In the Ganga basin, snowmelt contributes 10.3%, compared to 3.1% from glaciers.

○       In the Brahmaputra, snowmelt accounts for 13.2%; in the Indus, around 40%.

What is the Hindu Kush Himalaya Region?

●      Geographical Span:
 Covers 12 countries: Afghanistan, India, Nepal, China, Pakistan, Bhutan, Bangladesh, Myanmar, Mongolia, Kyrgyzstan, Tajikistan, Uzbekistan.

●      Nickname:
 Known as the Third Pole — world’s largest ice reserve outside Arctic and Antarctica.

●      Key Rivers:

○       South Asia: Indus, Ganga, Brahmaputra.

○       Central Asia: Syr Darya, Amu Darya.

○       East Asia: Tarim, Yellow, Yangtze.

○       Southeast Asia: Mekong, Salween, Irrawaddy.