Enviro News Asia, Geneva — Global river flows reached one of their driest levels in more than three decades in 2025, while freshwater storage and glaciers continued to decline, according to a new report from the World Meteorological Organization (WMO).
The WMO State of Global Water Resources 2025 report, released on September 17, 2026, found that the global water cycle has become increasingly erratic, shifting between periods of water scarcity and excess. It also showed that the number of river basins with normal conditions remained unusually low for the seventh consecutive year.
The report found that river discharge in 2025 was below normal across 36% of the world’s river basin area, based on simulations from 13 global hydrological models using observed weather data.
Only 34% to 38% of river basins recorded normal conditions each year during 2019–2025, compared with an average of 46% during 1991–2020.
WMO Secretary-General Celeste Saulo said the decline in long-term water reserves was becoming a growing concern because groundwater, glaciers and seasonal snowpacks traditionally act as buffers during periods of drought.
“We are depleting that savings account,” Saulo said, referring to the decline in global terrestrial water storage since around 2014–2016.
Terrestrial water storage includes freshwater held in groundwater, lakes, rivers, soil, vegetation, snow and ice. The report found a persistent negative trend since the mid-2010s, with below-normal storage affecting several regions between 2021 and 2025.
Glacier Loss Continues
Glacier retreat remained another major concern. For the fourth consecutive year, every major glaciated region recorded a net loss of ice mass.
During the 2025 hydrological year, glaciers lost an estimated 408 gigatonnes of mass, equivalent to approximately 1.1 millimeters of sea-level rise. Between 2023 and 2025, cumulative global glacier mass loss reached about 1,400 gigatonnes of water.
WMO said the loss of glacier mass creates both short-term hazards, including increased flood risks, and longer-term challenges for water security in communities that depend on glacier-fed water resources.
Some regions, including Central Asia, western South Asia, the Russian Arctic, Iceland, western Canada and the United States, recorded glacier mass balances among their three most negative years on record.
Groundwater Also Under Pressure
Groundwater conditions also showed signs of persistent depletion. Nearly two-thirds of monitored wells worldwide recorded conditions outside their historical range in 2025, with the overall balance shifting further toward deficits compared with 2024.
Persistent groundwater deficits during 2022–2025 affected parts of the Americas, Europe, the Middle East, India, southern Africa and Australia.
The report also identified widespread below-normal groundwater levels in parts of Central and Eastern Europe, the central United States, Mexico, Chile, Brazil, South Africa, India and Australia.
Water Disasters Hit Asia and Africa
Asia and Africa remained the regions most affected by water-related disasters. Together, they accounted for at least half of recorded water-related extreme events and more than 80% of associated reported deaths over the past five years.
During 2021–2025, persistent drought affected parts of South America, the Middle East and the Greater Horn of Africa, while severe flooding repeatedly affected West and Central Africa and Southeast Asia.
South and Southeast Asia experienced compound tropical cyclones and intense monsoon conditions in 2025, with reported deaths reaching up to 3,600 across affected countries, including Indonesia, Sri Lanka, Pakistan, Vietnam, Thailand, Malaysia and the Philippines.
WMO said the assessment also highlighted significant gaps in hydrological observations. Although data availability and country coverage have improved since the report was first published in 2021, Africa and Asia remain among the least represented regions in hydrological observations despite being heavily affected by extreme events.
Saulo stressed that water systems cross national borders, making international cooperation essential for monitoring and managing water resources.
“A river basin’s water balance depends on what happens in another country,” she said, calling for shared data, standards and early-warning systems.
The report incorporates observations and modelling from national meteorological and hydrological services, research institutions, data centres and other partners. Its scope has expanded from three to 15 hydrological variables since the first edition.
WMO said the findings underscore the need for stronger monitoring, improved early-warning systems and coordinated water management as climate variability and long-term changes continue to affect freshwater resources worldwide. (*)
