Nearly 60 per cent of rivers now flow with either too much or too little water.
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The world’s water cycle is becoming increasingly erratic, swinging between destructive floods and drought, according to a new report from the World Meteorological Organization (WMO).
It details how shrinking glaciers, droughts, unbalanced river basins and severe floods in 2024 are a sign of how climate change is making water resources increasingly more unpredictable.
“Water sustains our societies, powers our economies and anchors our ecosystems,” WMO Secretary-General Celeste Saulo said in a press release.
“And yet 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.”
An increasingly erratic water cycle
For the third year in a row, every single glacier region reported a loss of ice. In total, glaciers worldwide lost 450 gigatonnes of ice. That is the equivalent of a huge block of ice 7 kilometres tall, 7 kilometres wide and 7 kilometres deep or enough water to fill 180 million Olympic swimming pools.
This meltwater adds around 1.2 millimetres to global sea level rise in a single year, contributing to flooding risk for hundreds of millions of people living in coastal zones.
In many small-glacier regions, meltwater has already peaked or will peak soon. This is called the peak water point, after which annual runoff from melting decreases as the glacier shrinks.
Two-thirds of the world’s river basins saw abnormal conditions. The Amazon Basin and other parts of Africa were gripped by severe drought in 2024. In central, western and eastern Africa, alongside parts of Asia and Central Europe, conditions were wetter than normal.
Nearly 60 per cent of rivers now flow with either too much or too little water. The WMO says 2024 was the sixth year in a row where there has been a “clear imbalance”, reflecting the world’s increasingly erratic water cycle.
Extreme events are compounding the unpredictability of water resources. In Africa’s tropical zone, unusually heavy rainfall in 2024 resulted in around 2,500 deaths and 4 million people displaced. Europe experienced its most extensive flooding since 2013, with one-third of river networks exceeding high flood thresholds.
In Asia and the Pacific, record-breaking rainfall and tropical cyclones resulted in more than 1,000 fatalities. Brazil saw simultaneous extremes as catastrophic flooding in the south of the country killed 183 people, while the continuation of the 2023 drought in the Amazon basin affected 59 per cent of the country’s territory.
Billions at risk from unpredictable water resources
The report confirms what communities on the frontlines have known for years, according to Patience Mukuyu, WaterAid’s lead policy analyst on water security and climate resilience.
“Earth’s water cycle - our planet’s most vital system - is spiralling out of control.”
Mukuyu adds that the climate crisis is being felt through “one clear signal” - too little water or far too much.
“This is threatening food, energy, health, and human security worldwide, and costing billions of dollars and lives.”
An estimated 3.6 billion people around the world face inadequate access to water at least one month a day, according to UN Water. That number is expected to rise to more than 5 billion by 2050.
The WMO says the report highlights the critical need for improved monitoring and data sharing with reliable, science-based information, more important than ever.
“Without data, we risk flying blind,” Saulo added.
