Rivers worldwide faced one of their driest years in more than three decades in 2025, according to a comprehensive study by the World Meteorological Organization (WMO). The report highlights a significant decline in global freshwater resources held above and below the ground, including groundwater, lakes, rivers, snow, ice, and moisture within soil and vegetation. Terrestrial water storage was found to be 42% below normal levels last year, marking a persistent downward trend since around 2014-2016.
The WMO’s assessment reveals a heightened volatility in the global water cycle driven by climate change, causing rivers to swing between extremes of drought and flooding. In 2025, one of the warmest years on record, only about one-third of the world’s rivers exhibited normal flow conditions— the fewest since data collection began in 1991. Around 36% of global river basins experienced below- or much-below-normal flows, while 21% saw above-normal or much-above-normal flows, reflecting the increasing irregularity in water distribution.
Celeste Saulo, WMO Secretary-General, underlined the gravity of the issue by describing global water stores as a “savings account” that humanity is rapidly depleting. The report noted that glaciers, which contribute crucial meltwater to many rivers, have lost ice mass for the fourth consecutive year. In 2025 alone, 400 gigatons of ice melted, contributing 1.1 millimeters to sea level rise. This glacier loss represents the most significant reductions since the 1990s.
The study examined the entire water cycle, including river flows, groundwater recharge, evaporation, transpiration, land water storage, and snow and ice levels. Wayne Jenkinson, WMO Director of Hydrology, called the findings a clear signal to intensify global efforts to understand and manage water resources, emphasizing the need for increased data collection and sharing to better protect ecosystems and human populations.
The report also highlights numerous regional impacts from declining river flows and water quality. For example, record-low water levels in the Danube River caused an energy crisis in Hungary and Romania, forcing most nuclear reactors reliant on river water for cooling to shut down. The Mississippi River, a key water source for 50 U.S. municipalities, faces threats from chemical pollution that has contributed to low-oxygen dead zones in the Gulf of Mexico, as well as saltwater intrusion and intermittent droughts worsened by sea level rise.
Major African rivers such as the Nile, Niger, and Zambezi are under pressure from pollution and drought driven by climate change, which disrupt their ecosystems and the communities that depend on them. In England, none of the rivers are currently in good ecological or chemical health due to a combination of sewage and agricultural pollutants, persistent “forever chemicals,” and overextraction of water.
The WMO’s analysis of river conditions from 2021 to 2025 indicates persistent below-normal river flows in regions including parts of the Amazon and La Plata basins, North America, central and East Africa, central Asia, and the Middle East. Meteorological and hydrological agencies globally have reported a series of record-breaking floods and droughts in recent years, with many areas experiencing little recovery time between extreme weather events.
The report underscores the growing challenges facing global freshwater systems amid climate change and calls for urgent action to improve monitoring, management, and international cooperation to safeguard these critical natural resources.