Hindu Kush Himalayas
Stretching over 3500 kilometres and across eight countries – Afghanistan, Bangladesh, Bhutan, China, India, Nepal, Myanmar and Pakistan – the Hindu Kush Himalaya are arguably the world’s most important ‘water tower’, being the source of ten of Asia’s largest rivers as well as the largest volume of ice and snow outside of the Arctic and Antarctica
10 crucial river systems on the continent — Amu Darya, Indus, Ganga, Brahmaputra, Irrawaddy, Salween, Mekong, Yangtse, Yellow river, and Tarim
What does the report by the International Centre for Integrated Mountain Development highlight?
The authors of the 2024 HKH snow update analysed data from 2003 to 2024 and found significant fluctuations in snow persistence between November and April every year, when snow accumulates above ground.
Snow persistence is the fraction of time snow is on the ground. When this snow melts, it provides water to people and ecosystems. In the river basins of the Hindu Kush Himalaya (HKH), snowmelt is the biggest source of water in the streams.
The Ganga river basin — India’s largest — reached a record low snow persistence in 2024 (17% below the long-term historical average), the Hindu Kush Himalaya snow update of the International Centre for Integrated Mountain Development (ICIMOD) has reported.
The Brahmaputra and the Indus basins have suffered similarly, threatening water supply to millions of people.
Snow persistence in the Brahmaputra basin was 14.6% below normal in 2024, whereas In the Indus river basin, snow persistence fell 23.3% below normal
How important is snow persistence?
The primary reason for the lower persistence in 2024 was weak western disturbances
Western disturbances are low-pressure systems that originate over the Mediterranean Sea, the Caspian, and the Black Seas and bring rain and snow to the HKH region in winter.
The region where these storms originate experienced persistently high sea-surface temperatures
This disruption weakened and delayed the arrival of the western disturbance, resulting in reduced winter precipitation and snowfall in the HKH region.
The pattern of high temperatures and altered weather systems explains both the record low snow persistence in 2024 and similar historical records
The persistence of snow in China’s Yellow River basin exceeded the normal value by 20.2% in 2024.
The Yellow river basin is an area where the East Asian winter monsoon brings cold, dry air from Siberia and Mongolia
When this cold air mass interacts with moist air from other regions, particularly the Pacific Ocean, it can result in snowfall over the higher altitudes of the upper Yellow River basin
When the cold air from the east Asian winter monsoon systems interacts with moist air masses from the Pacific Ocean, it can result in snowfall at higher elevations in the eastern Himalaya
Climate change play in river basins receiving low levels of snowmelt this year
There is a need to reduce emissions, which would mitigate increasing sea-surface and ground temperatures, both of which lower the persistence of snow.
The key work for all of us concerned about a liveable future on the earth is to build the political will for our government representatives and business leaders to cut the cord on dirty fossil energy consumption and production, especially among G-20 countries, which account for 81% of all emissions
In the long term, reforestation with native tree species can help the ground retain more snow.
Better weather forecasting and early warning systems can also help local communities prepare for impending water stress.
Improving water infrastructure and developing policies for protecting areas receiving snowfall are important for long-term change
Communities’ involvement in local, national level decision-making and promoting regional cooperation are vital for comprehensive solutions for the sustainability of snow.
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