WMO report highlights increasingly erratic water cycle

 

The water cycle has become increasingly erratic and extreme, swinging between deluge and drought, according to a new report from the World Meteorological Organization (WMO). It highlights the cascading impacts of too much or too little water on economies and society.   The State of Global Water Resources report says only about one-third of the global river basins had “normal” conditions in 2024. The rest were either above or below normal – the sixth consecutive year of clear imbalance.   2024 was the third straight year with widespread glacier loss across all regions. Many small-glacier regions have already reached or are about to passthe so-called peak water point - when a glacier's melting reaches its maximum annual runoff, after which this decreases due to glacier shrinkage.   The Amazon Basin and other parts of South America, as well as southern Africa were gripped by severe drought in 2024, whilst 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.   “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 modelling systems and satellite observations from a wide range of partners.   The report highlights the critical need for improved monitoring and data sharing.   “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.

Anomalies of mean river discharge for the year 2024 compared to the period 1991–2020, derived from the modelled river discharge data obtained from an ensemble of 12 GHMS simulations.

Key messages   Climatic Conditions: 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, 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, Ganges, 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% of the wells (out of 37 406 from 47 countries which submitted groundwater data) had normal levels – the rest were too much or too little.   Glaciers:  2024 was the third consecutive year on record where there was widespread ice loss across all glaciated regions: with 450 Gt lost – the equivalent of a huge block of ice 7 kilometers tall, 7 km wide, and 7 km deep, or enough water to fill 180 million Olympic swimming pools. That much meltwater adds about 1.2 millimetres to global sea level in a single year, contributing to flooding risk for hundreds of millions of people living in coastal zones.   Record mass loss occurred in Scandinavia, Svalbard, and North Asia, while some regions like the Canadian Arctic and Greenland periphery saw more moderate losses. Nearer the Tropics, Colombian glaciers lost 5% in 2024. Extreme Events: Africa’s tropical zone experienced unusually heavy rainfall in 2024 compared to their historical norms, resulting in approximately 2,500 fatalities and 4 million people displaced. Europe experienced its most extensive flooding since 2013, with one-third of the river networks exceeding high flood thresholds. Asia and the Pacific were hit by record-breaking rainfall and tropical cyclones, resulting in over 1,000 deaths. Brazil experienced simultaneous extremes, with catastrophic flooding in the south of the country taking 183 lives and continuation of the 2023 drought in the Amazon basin, affecting 59% of the country’s territory.