Earth’s Freshwater Reserves Are Shrinking: Rivers Run Low, Glaciers Lose Ice

A dry season becomes harder to survive when the rivers, underground reserves and mountain ice that usually provide a safety net are running low. The World Meteorological Organization's State of Global Water Resources report, released on 17 September 2026, warns that these reserves are weakening, with 2025 ranking among the driest years for global river discharge in 35 years and freshwater stored on land continuing a decade of decline.

The assessment covers 2025 and patterns across 2021–2025, describing a water cycle increasingly marked by damaging shortages and excesses. For seven consecutive years, only 34–38% of river basins recorded normal flows, compared with an average of 46% during 1991–2020, leaving communities facing conditions that are harder to plan around.

Rivers and Underground Reserves Show Growing Strain

Below-normal river flows affected 36% of the world's basin area in 2025, according to simulations from 13 global hydrological models using observed weather data. Much of North America, parts of South America, Eastern Europe, the Middle East and Central Asia experienced unusually low discharge, putting pressure on water supplies that support households, farming and economic activity.

The picture varied sharply between regions, with higher flows across South and South-East Asia and parts of northern South America. Africa's Senegal, Niger, Lake Chad, Orange and Limpopo basins recorded above-normal flows, contrasting with very low discharge in the Nile, Congo and Zambezi basins; reservoir and lake levels broadly reflected these geographical differences.

Water stored in groundwater, rivers, lakes, soil, vegetation, snow and ice has followed a declining global trend since around 2014–2016. Nearly two-thirds of monitored groundwater wells recorded levels outside historical norms in 2025, with the balance moving further towards deficits than in 2024, and persistent shortages affecting parts of the Americas, Europe, India, the Middle East, southern Africa and Australia.

Melting Glaciers Weaken a Vital Water Safety Net

WMO Secretary-General Celeste Saulo described groundwater, glaciers and seasonal snow as reserves that help communities absorb dry periods, warning that this protection is being depleted. These stores build up or shrink over seasons and decades, meaning their loss can leave people more exposed when rainfall fails or drought stretches across several years.

Every major glacier region lost ice for the fourth consecutive year in 2025, with global losses estimated at 408 billion tonnes, equivalent to around 1.1 millimetres of sea-level rise. Cumulative glacier losses during 2023–2025 reached roughly 1,400 billion tonnes of water, a volume comparable to about one-third of annual freshwater withdrawals worldwide.

Regions including Central Asia, the Russian Arctic, Iceland, western Canada and the United States experienced some of their most severe annual glacier losses on record. Smaller-glacier regions may already have reached peak meltwater runoff, the point beyond which shrinking ice supplies less water, creating lasting concerns for downstream communities; European snow conditions were below normal in 2025.

Deadly Floods Expose Gaps in Data and Preparedness

Asia and Africa accounted for at least half of recorded water-related extreme events and more than 80% of associated reported deaths over the past five years. Repeated flooding left some communities little time to recover, and tropical cyclones combined with intense monsoon conditions contributed to up to 3,600 deaths across affected South and South-East Asian countries in 2025.

The financial damage was severe, with Jamaica reporting Hurricane Melissa losses equivalent to 41% of GDP and Cyclone Ditwah costing Sri Lanka around 4% of GDP. The report's coverage has expanded from three to 15 hydrological variables since 2021, but observation gaps remain particularly serious in Africa and Asia, strengthening the case for shared data, cross-border cooperation and early warnings that help people act before danger arrives.