Rivers around the world experienced one of their driest years in more than three decades in 2025, while glaciers continued to retreat and groundwater reserves declined, underscoring growing risks to water security, the World Meteorological Organization (WMO) said on Thursday (September 17).
The UN agency's annual State of Global Water Resources report found that the global water cycle has become increasingly erratic, with prolonged droughts, severe floods and shrinking natural freshwater reserves affecting communities and economies worldwide.
"Last year was one of the driest years for river discharge in 35 years. The past seven years have seen abnormal river flows," WMO Secretary-General Celeste Saulo told a news conference in Geneva.
"Water-related extreme events continue to devastate communities and economies," she said, adding that Asia and Africa accounted for at least half of all reported hydrological disasters and more than 80% of associated deaths over the past five years.
According to the report, below-normal river flows covered 36% of the world's river basin area in 2025, making it one of the driest years for rivers since records began 35 years ago. "Below-normal flows cover 36% of the world's basin area. That makes 2025 one of the driest years for rivers in 35 years," said Wayne Jenkinson, director of WMO's Division of Hydrology and Cryosphere.
The report found that terrestrial water storage – which includes groundwater, lakes, rivers, soil moisture, snow and ice – has been declining since the mid-2010s, pointing to a long-term depletion of freshwater reserves. "We are spending our reserves," Saulo said.
The report also highlighted accelerating glacier loss. For the fourth consecutive year, every major glaciated region on Earth recorded a net loss of ice mass in 2025.
In the 2025 hydrological year alone, glaciers lost nearly 408 gigatonnes of ice, contributing about 1.1 millimetres to global sea-level rise, according to WMO.
Over the three years from 2023 to 2025, cumulative glacier losses reached roughly 1,400 gigatonnes of water – equivalent to about one-third of annual global freshwater withdrawals.