World’s Water Cycle Becoming More Erratic, UN Raises Climate Alarm

UN Raises Alarm as Global Water Cycle Swings Between Drought and Floods

The global water cycle is becoming increasingly erratic, with the world facing more frequent swings between severe water shortages and excess rainfall, the United Nations warned on Thursday.

The World Meteorological Organization (WMO) said the deterioration is visible across major components of the planet’s freshwater system, including rivers, glaciers and groundwater. The agency also cautioned that a powerful El Niño could intensify drought and flooding risks in different parts of the world.

2025 marked another difficult year for rivers

The WMO’s annual State of Global Water Resources assessment found that 2025 was among the driest years for river flows recorded over the past 35 years.

It was also one of the warmest years ever recorded. At the same time, glaciers continued to lose ice across all monitored regions, while groundwater levels remained under pressure in many parts of the world.

The report said total freshwater storage—including water contained in groundwater, rivers, lakes, soil, vegetation, glaciers and snow—has continued its broader decline over the past decade.

Earth’s ‘water savings account’ is shrinking

Not every component of the water cycle reacts at the same speed. Rainfall, river discharge and soil moisture can change within days or weeks as weather patterns shift.

Groundwater and glaciers, however, respond much more slowly and act as long-term reserves during periods of drought.

WMO Secretary-General Celeste Saulo said these reserves have traditionally functioned as a buffer, preventing a single dry season or drought from immediately becoming a major water crisis.

But that protection is weakening.

“We are spending our reserves,” Saulo warned, highlighting the growing pressure on groundwater and glacier systems.

Glacier losses reach alarming levels

Glaciers continued to shrink at a rapid pace in 2025, marking the fourth straight year of significant ice loss across all regions.

The WMO estimated that glaciers lost a combined 1,400 gigatonnes of water between 2023 and 2025.

That volume is equivalent to the amount of water needed to fill approximately 560 million Olympic swimming pools and represents roughly one-third of annual global freshwater withdrawals.

The consequences extend beyond the glaciers themselves. Glacier-fed water supplies support communities, farming, energy production and ecosystems in many parts of the world.

• Groundwater levels also under pressure
• The report found that groundwater is showing similarly worrying signals.

Nearly two-thirds of monitored wells globally recorded conditions outside their historical range in 2025, according to Saulo.

Because groundwater can provide a crucial source of water during periods of low rainfall, continued depletion could make communities more vulnerable to future droughts.

The decline is taking place as water-related disasters become increasingly prominent, adding pressure to already stressed water systems.

Strong El Niño could bring more extremes

The changing water cycle could face additional disruption from El Niño, a natural climate pattern associated with warmer-than-average Pacific Ocean temperatures.

The current El Niño is expected to be particularly strong compared with comparable records from the past four decades.

Its influence can extend far beyond the Pacific, altering rainfall and wind patterns around the world.

Saulo warned that the phenomenon could increase drought risks in some regions while raising the likelihood of flooding elsewhere.

• Normal river conditions becoming less common
• The WMO found that abnormal river conditions have become a persistent feature.

Only about 36% of global river basins recorded normal flows in 2025. A similar share experienced below-normal discharge, while approximately 21% registered above-normal flows.

For the seventh consecutive year, normal river conditions represented a clear minority globally.

The findings illustrate how the water cycle is increasingly characterised by extremes rather than stable patterns.

Water crises cross borders

The WMO said improving the monitoring of the global water cycle will require much better access to reliable data.

Major gaps remain in observations, particularly in regions affected by severe water stress and extreme weather.

Saulo stressed the need for countries to cooperate through shared data, common standards and coordinated early-warning systems.

Water rarely follows political boundaries. River systems can cross several countries, while changes in rainfall, snow and glaciers upstream can directly affect populations downstream.

Recent disasters in the Himalayan region have demonstrated how events in one country can produce consequences across borders.

A growing challenge for governments

The WMO’s findings point to a broader challenge: managing water in a world where both shortages and excess are becoming more difficult to predict.

Declining long-term reserves could make droughts more damaging, while increasingly irregular rainfall and river flows could raise flood risks.

With another strong El Niño potentially amplifying these patterns, the UN is urging countries to strengthen monitoring, share water-related information and improve early-warning systems.

The message from the latest assessment is clear: the world is not simply facing less water in some places and more water in others. It is facing a more unpredictable water cycle, making long-term planning and international cooperation increasingly important.