The International Centre for Integrated Mountain Development (ICIMOD) has found that snow levels in Ganges, Brahmaputra and Indus basins of Hindu Kush Himalaya (HKH) have reached record low levels, according to a recent report. CIMOD, a regional intergovernmental organisation established in 1983, is working towards making the Hindu Kush Himalaya greener, more inclusive and climate-resilient.
Report Findings
Global Findings
- The Amu Darya river basin in Afghanistan recorded the lowest snowfall, while the Helmand River, which is important for drinking water supply of Iran and Afghanistan, recorded snowfall of about 32% below normal.
- Water levels in China’s Yellow River basin are 20.2% above normal, influenced by the interaction between cold winds from the East Asian winter monsoon and westerly winds from the Pacific Ocean.
In the context of India
- The report analyses data from 2003 to 2024, which shows that the Ganga River Basin has recorded the lowest snowfall in 22 years and the Brahmaputra Basin has also recorded a 14.6% reduction in snow cover compared to normal levels.
Reasons behind low snowfall
Weak western disturbances and impact of global warming
- The study shows that weak western disturbances from the warmer seas of the Mediterranean, Caspian Sea and Black Sea have reduced winter snowfall as well as rainfall in the Hindu Kush Himalayan region.
- Additionally, the rise in global temperatures has intensified the La Niña and El Niño events, further reducing the snow-bearing capacity of the region.
- The 1.5°C global temperature limit set under the Paris Agreement may not be sufficient for the Hindu Kush Himalaya (HKH) region, as the region is likely to experience a higher temperature increase than the global average.
Environmental Degradation
- Environmental degradation in the HKH region due to deforestation, overgrazing, unsustainable land practices as well as infrastructure development is causing severe impacts in the region such as soil erosion, biodiversity loss and water pollution.
Propagation of Invasive Species
- The spread of invasive species such as Cirsium arvense (Canada thistle) and Trifolium repens (white clover) poses a major threat to native Himalayan species, upsetting the delicate balance of the region’s ecosystem.
Snow Persistence
- Snow persistence refers to the duration that snow remains on the ground. When this snow melts, it is an important source of water for both people and the ecosystem.
- In the Hindu Kush Himalayan (HKH) river basins, snowmelt is the largest water source for rivers, contributing 23% of the annual runoff in the region’s 12 major river basins.
- These river basins provide water to about one-quarter of the world’s population and are an important source of freshwater for 240 million people in the HKH region.
- In the Ganges River Basin, snowmelt is particularly important as snowmelt contributes 10.3% of the Ganges’ water, while glaciers contribute only 3.1%.
- Similarly, in the Brahmaputra and Indus River Basins, snowmelt provides 13.2% and about 40% of the water supply, respectively, while glaciers provide 1.8% and 5%.
Hindu Kush Himalaya Region
Geographical Extent of HKH
- The Hindu Kush Himalaya (HKH) region extends across Afghanistan, Bangladesh, Bhutan, China, India, Kyrgyzstan, Mongolia, Myanmar, Nepal, Pakistan, Tajikistan and Uzbekistan.
Third Pole
- Often called the Third Pole because of its vast ice and snow reserves, it is very important from a climate perspective.
- The region has the largest concentration of ice and snow outside the Arctic and Antarctica.
- The ice and snow of the HKH region serve as an important water source for major rivers that flow through 16 countries in Asia.
- Major river systems from HKH and their destination
South Asia
- Indus, Ganges, Brahmaputra → Arabian Sea and Bay of Bengal
- Central Asia:
- Syr Darya, Amu Darya → East Aral Sea Basin
East Asia
- Tarim → Taklamakan Desert
- Yellow River → Gulf of Bohai
- Yangtze → East China Sea
Southeast Asia
- Mekong → South China Sea
- Chindwin, Salween, Irrawaddy → Andaman Sea