The World Meteorological Organization's analysis found 2025 was one of the driest years for global river flows in more than 35 years, with global terrestrial water storage about 42% below normal. The study used simulations from 13 global hydrological models driven by observed weather data and reported that only about a third of rivers were in the normal range last year. About 36% of global river basin area had flows below or well below normal while 21% had above or much-above-normal flows, reflecting an increasingly erratic water cycle. WMO secretary general Celeste Saulo warned the world is "depleting that savings account," noting a declining trend in terrestrial water storage since 2014, 16. The report also said all 19 major glacial regions lost ice mass for the fourth consecutive year, with 2025 glacier losses totaling 400 gigatons, adding 1.1 millimeters to sea level. WMO director of hydrology Wayne Jenkinson called for increased data collection and sharing to improve understanding and protection of water resources. The study linked low river flows to concrete impacts this year, including record-low Danube levels that forced shutdowns at Hungarian and Romanian nuclear reactors and growing threats to the Mississippi, Nile, Niger and Zambezi from drought, pollution and saltwater intrusion.
