Rivers across the world experienced one of their driest years in more than three decades in 2025, according to a comprehensive study of global water resources by the World Meteorological Organisation (WMO).
The WMO's assessment of the global water cycle revealed that the amount of freshwater held on or under the ground, including groundwater, lakes, rivers, snow, ice, and soil moisture, was 42% below normal globally last year. Celeste Saulo, secretary general of the WMO, stated that this indicates a depletion of the world's water savings account, with a persistent, decade-long decline in global terrestrial water storage since 2014–16.
In 2025, which was one of the warmest years on record, only about a third of rivers were within the normal flow range. The study, using simulations from 13 global hydrological models, found that 36% of the global river basin area experienced river flows below or well below normal, while 21% had above- and much-above-normal flows.
For the seventh consecutive year, the number of river basins with “normal” conditions was a clear minority, ranging between 34 and 38% in 2025, compared to an average of 46% between 1991 and 2020. Wayne Jenkinson, director of hydrology at the WMO, described the research as a call to action due to the continuing global decline in water resources.