The WMO State of Global Water Resources report is a comprehensive science-based annual assessment of the hydrological cycle and extreme events in 2025 and over the past five years.
Geneva, Switzerland, 17 September 2026 (WMO) - Rivers across the globe in 2025 had one of the driest years in more than three decades, according to a new report from the World Meteorological Organization (WMO). It shows a continuation of the long-term decline in Earth's freshwater storage and in glacier retreat - trends with serious implications for people and economies in the future.
The WMO State of Global Water Resources Report shows that the water cycle has become more erratic and unpredictable, swinging between too little or too much. The past seven years have seen the fewest rivers with "normal" flows since 1991.
Asia and Africa together accounted for at least half of all recorded water-related extreme events and more than 80% of reported associated deaths over the past five years, it says.
The report provides a comprehensive, science-based assessment of the entire water cycle loop, including river discharge, groundwater, evapotranspiration, land water storage, and snow and ice, as well as high-impact events. It covers the year 2025 and summarizes findings of the past five years since it was first published.
Some parts of this cycle are fast - such as precipitation, river flow, soil moisture - they respond to weather within days or weeks. Others, like groundwater, glaciers and seasonal snowpack, are slow, they accumulate or deplete over seasons to decades or longer. Traditionally these slow reserves have acted as the planet's savings account: a buffer that absorbs bad years so that a single drought or a single dry season does not translate directly into a water crisis," said WMO Secretary-General Celeste Saulo.
"We are depleting that savings account. Global terrestrial water storage has shown a declining trend since 2014-2016 - a persistent, decade-long signal. For the fourth consecutive year, every major glaciated region on Earth lost ice mass. Groundwater tells a similar story: nearly two-thirds of monitored wells worldwide showed conditions outside the historical norm in 2025, and the balance shifted further toward deficit compared with 2024, not toward recovery," said Celeste Saulo.
"At the same time, we are seeing more water-related disasters. The strengthening El Niño will increase the risk of drought in some areas, and flooding in others," she said.
The report highlights some major areas of concern:
- 2025 was one of driest years for river discharge globally in 35 years, with below-normal flows over 36% of global basin area. This is based on data from simulations from 13 global hydrological models, driven by observed weather data.
- For the seventh year in a row, the number of river basins with "normal" conditions was in a clear minority: ranging between 34-38%, compared to the average of 46% between 1991-2020, according to the report.
- Terrestrial water storage - the total amount of water stored in groundwater, lakes and rivers, soil moisture, vegetation and ice and snow - has been in decline since mid-2010s.
- 2025 marked the fourth consecutive year with widespread glacier loss across all regions - leading to short term hazards like floods and long-term water insecurity. Between 2023-2025 glaciers lost mass in each reporting year with cumulative global glacier mass loss at 1400 Gigatonnes of water. This is roughly equal to the water required to fill about 560 million Olympic-sized swimming pools, or about one third of annual freshwater withdrawals.
- In each of the past five years, National Meteorological and Hydrological Services around the globe reported record-breaking floods and droughts. Some places have had no recovery time between one event and the next.
"Water respects no borders. A river basin's water balance depends on what happens in another country. A glacier's retreat in one country reshapes water availability for populations hundreds of kilometers downstream. This is precisely why we need shared data, shared standards, and shared early warning - the exact function WMO exists to perform," said Celeste Saulo.
Dozens of experts from National Meteorological and Hydrological Services, data centres, researchers and partner institutions shared in situ observations, model outputs and space-based data and contributed to the report, which has expanded from three to 15 hydrological variables since the first edition in 2021. Country coverage has greatly expanded. However, Africa and Asia are still among the least represented regions in terms of hydrological observations in the report, even though they are most affected by extremes.
