Retreating glaciers threaten the food and water supply of two billion people around the world, the UN has warned, as current “unprecedented” rates of melting will have unpredictable consequences.
Two-thirds of all irrigated agriculture in the world is likely to be affected in some way by receding glaciers and dwindling snowfall in mountain regions, driven by the climate crisis, according to a Unesco report.
More than one billion people live in mountainous regions and, of those in developing countries, up to half are already experiencing food insecurity. That is likely to worsen, as food production in such regions is dependent on mountain waters, melting snow and glaciers, according to the World Water Development Report 2025.
Developed countries are also at risk: in the US, for example, the Colorado River basin has been in drought since 2000, and higher temperatures mean more of the precipitation is falling as rain, which runs off more quickly than mountain snow, exacerbating drought conditions.
Audrey Azoulay, the director general of Unesco, said: “Regardless of where we live, we all depend in some way on mountains and glaciers. But these natural water towers are facing imminent peril. This report demonstrates the urgent need for action.”
The rate of change of glaciers is the worst on record, according to separate research from the World Meteorological Organisation, which published its annual State of the Climate report this week. The largest three-year loss of glacier mass on record occurred in the past three years, the study found, with Norway, Sweden, Svalbard and the tropical Andes among the worst-affected areas.
Eastern Africa has lost 80 per cent of its glaciers in places and, in the Andes, between a third and a half of glaciers have melted since 1998. Glaciers in the Alps and the Pyrenees, the worst affected in Europe, have shrunk by about 40 per cent over roughly the same period.
The decline of glaciers has had a further impact, added Abou Amani, director of water sciences at Unesco, in that the loss of ice replaces a reflective surface with dark soil that absorbs heat. “Glaciers melting have an impact on the reflectivity of [solar] radiation and that will impact the whole climate system,” he warned.
More avalanches will also result, as rain falling on snow is a major factor behind avalanche formation. Pooling water from melting glaciers can also be released, causing sudden floods in valleys or to people living further down the slopes. Permafrost is also melting, releasing methane from the mountain soils that melting glaciers are uncovering.
A previous study, published last month in the peer-reviewed journal Nature, found that half of global glacier mass would be lost by the end of the century, if global heating was not halted.
Alex Brisbourne, a glacier geophysicist at the British Antarctic Survey, said: “Mountain glaciers contain some of the largest freshwater reservoirs on Earth. Meltwater released in the summer provides the water supply to a billion people and sustains an enormous amount of industry and agriculture. The impact [of such melting] will be felt way beyond those immediately downstream of the glaciers.”
These impacts are coming at a time when many food sources are already under strain.
Alvaro Lario, president of the International Fund for Agricultural Development and chair of UN-Water, called for more support for people who live in afflicted mountain regions.
“Water flows downhill, but food insecurity rises uphill. Mountains provide 60 per cent of our freshwater, but the communities that safeguard these vital resources are among the most food insecure,” he said.
“We must invest in their resilience to protect glaciers, rivers, and a shared future for all of us.” – Guardian
