The Ganga, Indus, and Brahmaputra river basins that support the livelihoods and water security of millions are staring at reduced flows in early summer as snow persistence, which signifies how long snow remains on the ground after snowfall, has declined alarmingly, according to a new report by Kathmandu-based International Centre for Integrated Mountain Development (ICIMOD).
The report mapped snow persistence across the Hindu Kush Himalayas (HKH), and found that it was at a two-decade low of 23.6 per cent. “This is worrying news for the water security of nearly two billion people across 12 major river basins that originate high in the HKH,” the report said. This is the third consecutive year of below-par seasonal snow across the region, ICIMOD added.
A 23-year time series of basin-scale snow persistence during the November to March snow season was monitored from 2003 to 2025, and it showed recurrent seasonal deficits coupled with annual fluctuations, especially in the last five years. The report said that snow persistence in the Ganga basin – 24.1 per cent below normal – was the lowest in 23 years. The highest snow persistence of 30.2 per cent above normal was recorded in 2015.
The snow persistence in the Indus basin declined to 24.5 per cent below normal, from a high of 19.5 per cent above normal in 2020. Ganga, Indus, Brahmaputra all depend on the Hindu Kush Himalayas.
About a fourth of the total river runoff in the HKH region is from snowmelt, and its share in the river basins increases from east to west. “Seasonal snowmelt is crucial for regional and local water availability, especially in the early melt season. It nourishes rivers for agriculture, hydropower, and several ecosystem services,” the report said.
Explaining the importance of the findings, Sher Muhammad, ICIMOD’s remote sensing specialist and lead expert for the snow report 2025, said, “We are observing such deficit situations occurring in continuous succession. This is an alarming trend. While our findings give a broad picture across the region, each must act based on the specific conditions of their river basins, particularly where seasonal snow melt is the major water source.
ICIMOD Director General Pema Gyamtsho said, “Carbon emissions have already locked in an irreversible course of recurrent snow anomalies in the HKH. To tackle this regional snow crisis and the challenges it creates for long-term food, water and energy resilience, we urgently need to embrace a paradigm shift toward science-based, forward-looking policies and foster renewed regional cooperation for transboundary water management and emissions mitigation.”
Story continues below this ad
The report recorded a bigger decline across the Mekong (51.9 per cent), Salween (48.3 per cent), and Tibetan Plateau (29.1 per cent) river basins in South East Asia.
© The Indian Express Pvt Ltd
Source link
[ad_3]
[ad_4]