Most rivers swinging between drought and deluge on erratic global water cycles
The water cycle has become increasingly erratic and extreme, swinging between deluge and drought, and leading to normal conditions across only 40 per cent of the world’s rivers during 2024, the World Meteorological Organization (WMO) has said.
According to the State of Global Water Resources released by the WMO earlier this month, around 60 per cent of rivers globally showed either too much or too little water during 2024, which was the sixth year in a row showing an erratic hydrological cycle. It was also the third straight year with widespread glacier loss across all regions. Many small-glacier regions have already reached or are about to pass the so-called peak water point—when a glacier’s melting reaches its maximum annual runoff, after which this decreases due to glacier shrinkage, the report states.
Overall, 2024 was dry and hot, but marked disparities appear in regional patterns: While certain areas suffered severe drought, others endured multiple floods, the report, which highlights the cascading impacts of too much or too little water on economies and society, said.
The Amazon Basin and other parts of South America, as well as southern Africa were gripped by severe drought in 2024, while there were wetter-than-normal conditions in central, western and eastern Africa, parts of Asia and Central Europe, it says.
“Water sustains our societies, powers our economies and anchors our ecosystems. 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,” said WMO Secretary-General Celeste Saulo in an official statement.
“Reliable, science-based information is more important than ever before because we cannot manage what we do not measure. The WMO’s State of Global Water Resources Report 2024 is part of WMO’s commitment to provide that knowledge,” she said.
The annual State of Global Water Resources Report is one of a suite of WMO reports which provide intelligence and insights to decision-makers. It is an authoritative assessment of global freshwater availability, including streamflow, reservoirs, lakes, groundwater, soil moisture, snow and ice. It is based on data contributed by WMO Members, as well as information from global hydrological modeling systems and satellite observations from a wide range of partners.
The report highlights the critical need for improved monitoring and data sharing through enhanced investments globally.
“Continued investment and enhanced collaboration in data sharing are vital to close monitoring gaps. Without data, we risk flying blind,” said Celeste Saulo.
An estimated 3.6 billion people face inadequate access to water at least a month per year and this is expected to increase to more than 5 billion by 2050, according to UN Water, and the world falling far short of Sustainable Development Goal 6 on water and sanitation.
The year 2024 was the hottest year on record and began with an El Niño event which impacted major river basins. It contributed to droughts in northern South America and the Amazon Basin and southern Africa.
It was wetter-than-average in Central and western Africa, the Lake Victoria basin in Africa, Kazakhstan and Southern Russia, Central Europe, Pakistan and Northern India, Southern Iran, and North-Eastern China
Rivers and lakes: In the past six years only about one-third of the global river catchment area had normal discharge conditions compared to the 1991-2020 average. This means that two thirds have too much or too little water—reflecting the increasingly erratic hydrological cycle.
There was much below-normal discharge across key river basins, including the Amazon, São Francisco, Paraná, and Orinoco in South America, and the Zambezi, Limpopo, Okavango, and Orange basins in southern Africa.
Extensive flooding occurred in West African basins in Senegal, Niger, Lake Chad, Volta. There was above normal river discharge across Central Europe and parts of Asia, swelling major basins including the Danube, Ganga, Godavari, and Indus.
Nearly all out of selected 75 main lakes across the globe saw above or much above normal temperatures in July, affecting water quality.
Reservoir inflows, groundwater, soil moisture and evapotranspiration trends highlighted regional contrasts, with recharge in wetter areas such as parts of Europe and India, but persistent deficits in parts of Africa, the Americas, and Australia.
Over-extraction of groundwater continued to be a problem in some areas, reducing future water availability for communities and ecosystems and further stressing global water resources. Only 38 per cent of the wells (out of 37406 from 47 countries which submitted groundwater data) had normal levels—the rest were too much or too little.
