Last year’s record heat led to prolonged droughts and extreme floods across the globe.
Published On 18 Sep 2025
Climate change is making the Earth’s water cycle increasingly erratic, resulting in extreme swings between deluge and drought across the world, the United Nations has warned.
The UN’s World Meteorological Organization (WMO) has flagged alarming trends in its latest report, illustrating how the global water cycle is becoming unpredictably extreme. With shrinking glaciers, prolonged droughts, imbalanced river basins, and devastating floods, the ramifications are clear: our planet’s water resources are under escalating pressure.
WMO chief Celeste Saulo emphasized the impact of these changes, stating, “The world’s water resources are under growing pressure, and, at the same time, more extreme water-related hazards are having an increasing impact on lives and livelihoods.” This statement encapsulates the urgency of addressing the changes in how we experience and manage water.
The international group of scientists involved in the report meticulously assessed freshwater availability and water storage across the globe. They examined the status of lakes, river flows, groundwater, soil moisture, snow cover, and ice melt, all of which contribute to our understanding of the water cycle’s overall health.
Last year marked a significant turning point, as it was identified as the hottest on record. This rise in temperatures resulted in prolonged droughts in crucial regions such as northern South America, the Amazon Basin, and Southern Africa. Meanwhile, the report also highlighted the contrasting experiences of regions like Central Africa, Europe, and Asia, which were grappling with excessive rainfall, leading to catastrophic floods and deadly storms.
An unsettling statistic reveals that 2024 marked the sixth consecutive year with a discernible “clear imbalance” in the world’s river basins. According to WMO, two-thirds of these basins are experiencing either excessive water or insufficient supply, a clear reflection of the increasingly erratic hydrological cycle.
While the Earth has its natural climate variability, the long-term trends indicate a troubling acceleration of the water cycle. Stefan Uhlenbrook, WMO’s director of hydrology, pointed out the growing difficulty in making accurate predictions due to the heightened unpredictability. “It’s more erratic, so either too much or too low on average flow per year,” he explained.
The mechanics behind this erratic behavior can be traced back to global warming. As temperatures rise, the atmosphere has an increased capacity to hold water vapor, leading to longer dry periods in some regions while causing more intense rainfall events in others. “The climate changing is everything changing, and that has an impact on the water cycle dynamics,” Uhlenbrook summarized.
Furthermore, the WMO expressed concern over declining water quality in essential lakes, attributed to warmer temperatures. Over the past three years, glaciers have continued to shrink globally, with their meltwater contributing approximately 1.2 mm to global sea levels within just one year. This rising sea level poses an escalating flooding risk for millions living in coastal areas.
As the challenges mount, the WMO emphasizes the need for enhanced monitoring and data-sharing practices. “Understanding and quantifying water resources and hydrological extremes … is critical for managing risks,” the report underscored, highlighting the urgent need to address the threats posed by droughts, floods, and glacier loss.