The Hindu Kush Himalayan (HKH) region, home to the world's largest ice reserves outside the Arctic and Antarctic, is experiencing an unprecedented crisis as glaciers melt at alarming rates. According to the United Nations World Water Development Report 2025, which was released on Friday, marking the first-ever World Day for Glaciers, mountains provide up to 60% of the world’s annual freshwater flows. More than one billion people live in mountainous regions, and over two billion directly rely on water originating from mountains for their drinking water, sanitation and livelihoods. In short, 2 billion people are at risk of water shortages due to melting glaciers.
The urgency of the situation was tragically witnessed in August last year, when a glacial lake outburst flood (GLOF) in Nepal’s Namche region swept away several homes in Thame village. Scientists at the International Centre for Integrated Mountain Development (ICIMOD) had been monitoring the Thyangbo lake using satellite imagery, warning that rising global temperatures increase the likelihood of such disasters. "This is just the beginning. As temperatures rise, the risk of more devastating GLOFs grows exponentially," said ICIMOD researchers.
"This is not just about melting ice; it's about the survival of communities that depend on these glaciers for their water supply," said Celeste Saulo, Secretary-General of the World Meteorological Organization (WMO).
The HKH region spans eight countries — Afghanistan, Pakistan, India, Nepal, Bhutan, China, Bangladesh, and Myanmar. These glaciers serve as critical freshwater sources for some of the most densely populated areas on the planet. As they shrink, the impacts are cascading — initially leading to floods and landslides, followed by long-term water scarcity that threatens food security and livelihoods. "Millions of people, especially in rural farming communities, will struggle to access clean water if these trends continue," warned Prof Michael Zemp, Director of the World Glacier Monitoring Service (WGMS).
Glacial lakes are formed as glaciers retreat, with natural moraine walls acting as unstable dams. If these walls collapse, devastating floods can occur. The UN report notes that the HKH and other mountain regions, including the Hengduan, Tien Shan, and Qilian mountains, lost ice 65% faster in the past decade than in the previous one. "The HKH glaciers are melting faster than the global average. This is a crisis for water security in Asia and beyond," said Abou Amani, Director of Water Sciences at UNESCO. Despite the region housing more than 50,000 glaciers, only 28 are actively monitored.
Between 2000 and 2023, global glacier mass loss totaled 6,542 billion tonnes, with the HKH region among the most affected. Glacier melt has already contributed 18 millimeters to global sea-level rise, a number expected to grow as ice loss accelerates. Every millimeter of sea-level rise exposes an additional 200,000 to 300,000 people to annual flooding. "This is equivalent to losing an ice block the size of Germany with a thickness of 25 meters," said Zemp.
The Indo-Gangetic basin, heavily dependent on glacial meltwater for agriculture, faces imminent challenges as erratic water availability threatens food production. "Glacier-fed rivers are the lifeblood of South Asian agriculture. If we lose them, we risk devastating food shortages," said Dr Jos Timmerman, a water policy expert contributing to the report. The HKH region supports large agricultural economies that depend on predictable water cycles. In some areas, glacial water accounts for up to 70% of river flows during dry seasons.
Hydropower, a key energy source for many countries in the region, is also at risk. Glacial-fed rivers power numerous hydroelectric plants, but with shrinking ice reserves, energy generation could become increasingly unpredictable. "Hydropower plants are already seeing fluctuations in water availability, making electricity generation less reliable," said Dr Hanna Plotnykova, a climate risk analyst at UNESCO.
The loss of glaciers will also intensify natural hazards, including GLOFs, which have already caused deadly disasters in Nepal and Bhutan. The UN report warns that more than one million people live within 10 km of a glacial lake in the HKH region, putting them at extreme risk. Other regions are also facing alarming glacial decline. In the Andes, glaciers have lost 30-50% of their mass. The Alps, which serve as the water source for European rivers like the Rhine and Danube, are losing ice at record rates. The report notes that if current trends persist, Mount Kenya, Rwenzori, and Kilimanjaro glaciers could disappear entirely by 2040, depriving local communities of a crucial water source.
The report calls for urgent action to mitigate the impacts of glacier melt. Strengthening early warning systems for floods and landslides, investing in sustainable water management, and enhancing regional cooperation are crucial steps. The Indus Waters Treaty between India and Pakistan, which governs shared water resources, is cited as a framework that could be adapted to address climate-induced water variability. Additionally, integrating Indigenous knowledge into water conservation efforts is essential, as local communities have long practiced sustainable water management techniques suited to the region’s geography. "Indigenous wisdom holds valuable lessons on adapting to water scarcity, and we need to incorporate these strategies into modern policies," said Audrey Azoulay, Director-General of UNESCO.
Financial support remains a major challenge. While international climate adaptation funds exist, many HKH countries struggle to access these resources. The report urges governments and financial institutions to prioritise mountain-specific projects, including glacier monitoring, water conservation, and climate-resilient infrastructure.