The world's freshwater supplies are declining at an accelerating pace, with glaciers shrinking for the fourth consecutive year, river flows at near-record lows, and groundwater levels falling across much of the globe. The World Meteorological Organization (WMO), which presented its annual report in Geneva, found that 2025 was one of the three driest years for river discharge in the past 35 years. In total, water with a mass of approximately 1,400 gigatonnes — enough to fill 560 million Olympic swimming pools — was lost from freshwater systems worldwide. WMO Secretary-General Celeste Saulo described glaciers and groundwater reserves as "the planet's savings account," warning bluntly: "We are emptying this account."

The picture painted by the data is stark at every scale. Nearly two-thirds of monitored groundwater wells recorded below-average levels last year, with Central and Eastern Europe among the hardest-hit regions. Separately, a comprehensive study published in the journal Scientific Data found that the Greenland and Antarctic ice sheets — the two largest bodies of ice on Earth — lost more than 11 trillion tonnes of ice between 1979 and 2023, raising global sea levels by 3.14 centimetres. Crucially, more than four-fifths of that ice loss came not from surface melting but from glaciers flowing faster into the ocean in response to warming seas, a process researchers warn is difficult to reverse. While the rate of loss slowed slightly between 2020 and 2023, scientists stress this does not signal a reversal of the long-term trend.

Climate scientists explain that warming amplifies the problem in ways that are not always visible. For every degree of atmospheric warming, the air can hold roughly seven percent more water vapour — meaning more water is pulled out of soils, rivers, and glaciers and suspended in the atmosphere or carried into the oceans, where its salt content makes it unusable for drinking or agriculture. "The soil dries out faster, and when heavy rainfall does come, parched ground can no longer absorb it," notes climate researcher Mojib Latif. Some experts now speak of a global "water bankruptcy" — a term deliberately chosen to convey that, unlike a crisis, the loss of glaciers is permanent: once they are gone, so is the freshwater they held.

The consequences extend far beyond drinking water. Freshwater systems underpin agriculture, industry, biodiversity, and coastal stability. The 3.14-centimetre rise in sea levels attributable to ice sheet loss alone has already exposed an additional six to nine million people to flooding and coastal erosion risks, according to researchers at Northumbria University in northeast England. In Asia and Africa, more than half of all reported hydrological extreme events and over 80 percent of related deaths occurred in the past five years, the WMO noted. Looking ahead, the organisation warned that an intensifying El Niño weather pattern is likely to worsen droughts in some regions and flooding in others.

Experts are clear that tackling climate change is the most effective lever available. "We have known for decades that climate change was coming. We are now in the middle of it. Measures are being taken, but we are acting far too slowly," says water scientist Marjolein Vanoppen. While technological solutions such as seawater desalination exist, they are energy-intensive and costly, and cannot substitute for the broader ecological functions that healthy freshwater systems provide. The challenge, Vanoppen argues, is less about securing drinking water for wealthy nations than about protecting the biodiversity and agricultural systems that billions of people — particularly in the Global South — depend on every day.