Geneva (AFP) – The planet’s water cycle is becoming increasingly erratic, swinging between too little and too much, the United Nations warned Thursday, with an unprecedented El Nino expected to exacerbate the long-term trend.

Last year was among the driest for the world’s rivers in over three decades, the UN’s World Meteorological Organization said in a report.

In 2025 – one of the warmest years on record – glaciers also shrank across all regions, even as groundwater levels in many parts of the world are in multi-year decline, it found.

Overall, the WMO’s annual State of Global Water Resources report showed that the Earth’s freshwater storage – the total amount of water stored in groundwater, lakes and rivers, soil moisture, vegetation and ice and snow – continued a decade-long decline.

Some elements of the water cycle change rapidly – like precipitation, river flow and soil moisture, responding to weather within days or weeks.

WMO Secretary-General Celeste Saulo voiced particular concern about the decline in “slow reserves”, like groundwater and glaciers, which she said had traditionally served as the planet’s “savings account”.

They have served as “a buffer that absorbs bad years so that a single drought or a single dry season does not translate directly into a water crisis”, she told reporters.

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