World’s water cycle becoming more unpredictable, UN warns

The planet's water cycle is becoming increasingly unpredictable, the United Nations warned on Thursday. An unprecedented El Nino is set to exacerbate the long-term trend of water shortages and floods. According to a report by the World Meteorological Organization (WMO), 2025 was among the three driest years for rivers in over three decades.

This trend is accompanied by a decline in groundwater and glacier reserves, which traditionally acted as a buffer against water crises. Glaciers have been shrinking rapidly, losing a cumulative global mass of 1,400 gigatonnes of water between 2023 and 2025, enough to fill 560 million Olympic-sized swimming pools. Groundwater levels in many parts of the world have also been declining for multiple years.

The WMO's annual State of Global Water Resources report found that abnormal river flows were already a concern before El Nino hit, with 2025 among the driest years in 35 years. The World Meteorological Organization's secretary-general, Celeste Saulo, expressed particular concern about the depletion of slow reserves like groundwater and glaciers.

She warned that the planet is "depleting that savings account" and urged for shared data, standards, and early warnings to address the growing risks of water-related disasters.