Bresvelbreen iceberg in Svalbard and Jan Mayen, Norway on July 7, 2024. Sebnem Coskun / Anadolu via Getty Images

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Melting glaciers threaten the supply of food and water for billions across the globe, the United Nations warned in its 2025 World Water Development Report: Mountains and Glaciers: Water towers.

Mountains supply 55 to 60 percent of the planet’s annual freshwater flow, with two billion people reliant on the waters flowing from them.

“As the world’s water towers, mountains provide life-sustaining fresh water to billions of people and countless ecosystems; their critical role in sustainable development cannot be ignored,” a press release from the United Nations Educational, Scientific and Cultural Organization (UNESCO) said.

The most recent edition of the report emphasizes the importance of alpine glaciers and other mountain water sources, which are essential to meet basic human needs like drinking water and sanitation.

According to the report, 2.2 billion people did not have access to safe drinking water in 2022, while 3.5 billion lacked safely managed sanitation.

“Climate change is accelerating glacier melt, decreasing snow cover, increasing permafrost thaw, and causing more extreme rainfall events and natural hazards leading to more variable, erratic and uncertain water flows,” the press release said. “This highlights the urgency of improving mountain water governance through integrated river basin management, finance, and knowledge- and capacity-building, to meet the world’s ever-growing demand for water.”

Mountain waters are essential to the food and energy security of billions of people who live in and around mountainous regions, as well as areas downstream. These waters also support water-reliant industries important to economic growth.

Two-thirds of irrigated agriculture globally will likely be impacted by receding mountain glaciers and less snowfall in mountainous regions, the report said, as The Guardian reported.

“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,” said UNESCO Director General Audrey Azoulay.

The glacial rate of change is the worst ever recorded, separate research by the World Meteorological Organization (WMO) said in its State of the Global Climate 2024 report, published earlier this week.

WMO found that the last three years saw the largest ever loss of glacier mass, with the tropical Andes, Sweden, Norway and Svalbard among the most-impacted areas.

“As the ‘water towers’ of the world, mountains are an essential source of fresh water. They store water in the form of ice and snow during cold seasons, releasing it during warmer seasons as a major source of fresh water for users downstream. Mountains play a unique and critical role in the global water cycle, and they affect atmospheric circulation, which drives weather and precipitation patterns,” the press release said.

According to Abou Amani, UNESCO’s director of water sciences, glacial decline also means the reflective ice surface is replaced by dark soil, which absorbs heat.

“Glaciers melting have an impact on the reflectivity of [solar] radiation and that will impact the whole climate system,” Amani warned, as reported by The Guardian.

President of the International Fund for Agricultural Development Alvaro Lario, who is also chair of UN-Water, said more support is needed for those living in affected mountain regions.

“Water flows downhill, but food insecurity rises uphill. Mountains provide 60% of our freshwater, but the communities that safeguard these vital resources are among the most food insecure,” Amani said, as The Guardian reported. “We must invest in their resilience to protect glaciers, rivers, and a shared future for all of us.”

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