Amid reports of growing water shortages in heat-affected regions of India, a new alarm has been raised regarding an impending water crisis with a new report saying that the Hindu Kush Himalaya (HKH) region is experiencing significantly reduced snow persistence, critical for water supply to downstream communities.

The latest Snow Update Report - 2024 released by the International Centre for Integrated Mountain Development (ICIMOD) on Monday said that snow levels across the region are nearly 20% below normal, with the most significant declines observed in western areas where dependence on snowmelt for water supply is highest.

This decline, affecting approximately 23% of water flow in major river basins originating from the HKH, poses grave implications for water security. Known as the world’s most important ‘water tower’, the HKH is the source of ten of Asia’s largest rivers including Ganga and Brahamputra in India and holds the largest volume of ice and snow outside of the Arctic and Antarctica. It stretches over 3500 kilometres and across eight countries – Afghanistan, Bangladesh, Bhutan, China, India, Nepal, Myanmar and Pakistan.

Regarding India, the report said, snow persistence dropped 17 per cent below normal in the Ganga basin and 14.6 per cent below normal in the Brahmaputra basin,

The HKH is heavily dependent on the cryosphere -- frozen water on the Earth’s surface, including snow, permafrost, and ice from glaciers, lakes and rivers. This frozen water is a critical source of freshwater for around 240 million (24 crore) people living in the HKH region and has far-reaching benefits for around 1.65 billion (165 crore) people downstream. Snowmelt accounts for around 23 per cent of the total water flow of 12 major river basins originating in the HKH. However, its contribution varies from river to river, representing 74 per cent of the Amu Darya’s flow, 77 per cent of the Helmand’s flow, and 40 per cent of the Indus’ flow.

Monitoring shows snow levels are almost a fifth below normal across the region this year, with the most dramatic declines in the west, where its contribution to water supply is the highest.

The Indus basin has fallen to 23.3 per cent below normal, the lowest level in 22 years. The previous lowest year for this basin was 2018, with a 9.4 per cent shortfall. The Mekong basin had the smallest variation from normal, with snow persistence around 1 per cent below normal.

“We have seen a pattern of decreasing amounts and persistence of snow across the Hindu Kush Himalaya, with 13 of the past 22 years registering lower-than-normal seasonal snow persistence,” said ICIMOD cryosphere specialist Sher Muhammad, who is also author of the report.

“This is a wake-up call for researchers, policymakers and downstream communities. Lower snow accumulation and fluctuating snow levels pose a serious increased risk of water shortages, particularly this year,” he said.

Miriam Jackson, ICIMOD’s senior cryosphere specialist, said agencies must take proactive steps to address possible drought situations, especially in early summer. “Plans must be updated to accommodate water stress, and communities need to be notified of the risks.”

The experts said promoting rainwater harvesting and establishing local water committees may help mitigate the immediate impacts of below-normal snowfall on the water supply in the HKH region.

However, to ensure long-term resilience to climate change, countries sharing trans-boundary rivers must collaborate to update their water management laws.