Widespread water insecurity is the result of decades of overuse, as well as shrinking supplies from lakes, rivers, glaciers and wetlands, the researchers found.

Children stand nearby a dried-up hand-pump, amid serious water crisis in Kabul, Afghanistan, Aug. 29, 2025.Sayed Hassib / Reuters file

The world is facing irreversible water "bankruptcy," with billions of people struggling to cope with the consequences of decades of overuse as well as shrinking supplies from lakes, rivers, glaciers and wetlands, U.N. researchers said on Tuesday.

Nearly three-quarters of the global population live in countries classified as "water insecure" or "critically water insecure," and 4 billion people face severe water scarcity at least one month per year, the United Nations University Institute for Water, Environment and Health warned in a report.

"Many regions are living beyond their hydrological means, and many critical water systems are already bankrupt," said Kaveh Madani, lead author and director of the institute.

"By acknowledging the reality of water bankruptcy, we can finally make the hard choices that will protect people, economies and ecosystems," he said.

The report said water supplies are "already in a post-crisis state of failure" after decades of unsustainable extraction rates that have drawn down water "savings" contained in aquifers, glaciers, soils, wetlands and river ecosystems, with supplies also degraded by pollution.

More than 170 million hectares of irrigated cropland - an area larger than Iran - are under "high" or "very high" water stress, and economic damage from land degradation, groundwater depletion and climate change amounts to more than $300 billion a year worldwide, the report said.

Three billion people and more than half of global food production are concentrated in areas already facing unstable or declining water storage levels, while salinization has also degraded more than 100 million hectares of cropland, it said.

The researchers wrote that the current approach to solving water problems was no longer fit for purpose, and the priority was not "returning to normal" but a new "global water agenda" designed to minimize damage.

However, Jonathan Paul, geoscience professor at Royal Holloway, University of London, said the report did not address one major factor behind the crisis.

"The elephant in the room, which is mentioned explicitly only once, is the role of massive and uneven population growth in driving so many of the manifestations of water bankruptcy," he said.