Melting glaciers threaten water supplies: Report

Mumbai: Climate disruption, biodiversity loss, and unsustainable activities are transforming mountain environments at an unprecedented rate, threatening the water resources upon which billions of people and countless ecosystems depend.

According to a comprehensive report published under the aegis of the United Nations coinciding with the World Day for Glaciers (21 March) and World Water Day (22 March), mountains provide up to 60 per cent 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.

There is now an urgent need for international cooperation and adaptation strategies and actions to face the unfolding crisis in our mountains and glaciers, says the United Nations World Water Development Report 2025, published by UNESCO on behalf of UN-Water.

“Regardless of where we live, we all depend in some way on mountains and glaciers. But these essential natural water towers are facing imminent peril,” said Audrey Azoulay, Director-General, UNESCO.

“Water flows downhill, but food insecurity rises uphill. The earth’s mountains provide 60 per cent of our freshwater, but the communities that safeguard these vital resources are among the most food insecure. We must invest in their resilience to protect glaciers, rivers - and a shared future for all of us,” said Alvaro Lario, President, International Fund for Agricultural Development (IFAD) and Chair of UN-Water.

While images of receding glaciers capture the public’s attention, they are just one example of the rapid changes happening in mountain areas. In many regions, freshwater flows depend more on seasonal snowpack melt than on glaciers.

Due to climate disruption, rapid changes in the amount, frequency and regularity of snowfall are severely disrupting the water supply, creating unstable environments for biodiversity, and unpredictable conditions

for human livelihoods. In Japan, for example, the iconic snowcap on Mount Fuji, a UNESCO World Heritage site, has recently started appearing nearly one month later than usual.

These changes in precipitation are also increasing the risk of natural disasters such as droughts and glacial lake outburst floods. The Colorado River in North America, which serves about 40 million people,

gets most of its water from snowfall in the Rocky Mountains. The river basin has been in drought since 2000. The situation may become exacerbated by warmer temperatures, which are causing more precipitation to fall as rain, which runs off more quickly than mountain snow.

Climate disruption is also being felt strongly in mountain regions with no recorded glaciers or snowmelt, where water flows originate instead from rainfall. In tropical regions, such as Madagascar, changes in mountain waters are impacting the irrigation of cacao, rice and fruit production – some of the island nation’s most important agricultural exports.

National policies for water, agriculture, industry and energy tend to favour more populous

river basin areas, while mountains generally receive much less attention – or are often only considered as sources for downstream users.

Mountain regions are vital to sectors such as pastoralism, forestry, tourism and energy production. In the Andean countries 85 per cent of hydropower is generated from mountain areas. Mountains also provide high-value products such as medicinal plants, timber and other forest products, unique mountain livestock and specialty agriculture products – all of which are water-dependent.

However, the Report indicates that glaciers across the world are melting at unprecedented rates, and that mountain waters are often the first to be exposed – and the most vulnerable – to the severe consequences of climate and biodiversity disruptions.