Five months before devastating flash floods struck Nepal, two reports had warned of accelerating glacier loss across the Hindu Kush Himalaya (HKH), raising concerns for communities that depend on the region’s glaciers and rivers.
The reports, published in March by the International Centre for Integrated Mountain Development (ICIMOD), said glaciers across the HKH were losing ice at an increasing rate. The Kathmandu-based intergovernmental organisation found that up to 27 metre of glacial ice thickness was lost since 1975.
Glacier loss accelerating across Himalayas
The findings pointed to growing risks for the “nearly two billion people downstream who depend on meltwater from the 'Water Towers of Asia'.”
One of the reports, the 'HKH Glacier Outlook 2026', examined 38 monitored glaciers and found that glacial wastage had doubled since 2000. It warned that "parts of the Himalayan cryosphere may be nearing critical tipping points toward irreversible retreat", reported NDTV.
Another ICIMOD assessment found that between 1990 and 2020, HKH glaciers had lost about 12 per cent of their total area and 9 per cent of their estimated ice reserves.
Data gaps remain a concern
The reports also highlighted major gaps in glacier monitoring across the region. Of the 38 glaciers assessed, only seven met the global monitoring standards set by the World Glacier Monitoring Service.
Several areas with significant glacier cover, including the Karakoram, Sikkim, Zanskar and Bhutan, remain largely unmonitored, according to the reports.
The HKH contains the largest volume of ice outside the polar regions, with more than 63,700 glaciers covering over 55,000 sq km. These glaciers feed 10 major river systems in Asia and support food, water, energy and livelihoods for billions of people.
Scientists investigate cause of Nepal floods
The precise cause of the recent Nepal floods, which killed 272 people, remains under investigation. Scientists are examining several possible factors, including an ice-rock avalanche at high altitude.
ICIMOD researchers are investigating whether ice and rock debris entered the Lende Khola, a tributary of the Bhote Koshi River, triggering a sudden surge carrying water, sediment and boulders downstream.
Mohd Farooq Azam, senior cryosphere specialist at ICIMOD and associate professor at the Indian Institute of Technology Indore, told PTI, "It is related to climate change because the snow covers are reducing, the glaciers are receding, more rocky or barren areas are exposed - they absorb more heat which makes the slopes more vulnerable,"
He said the exact cause was yet to be established but pointed to reduced snow cover, glacier retreat and possible permafrost degradation.
Himalayan glaciers face rising temperatures
ICIMOD said at least 78 per cent of the glacier area between 4,500 and 6,000 metres is highly exposed to elevation-dependent warming.
The organisation also found that glacier losses vary across the region. The eastern Hengduan Shan mountains recorded the highest percentage of area loss, with some areas losing up to 33 per cent of their glacier area over three decades.
The largest absolute losses, however, were concentrated in the Indus, Ganges and Brahmaputra basins, which together contain more than 74 per cent of the region’s glaciers.