WMO report: Water security for billions of people is under threat
The water cycle is becoming unbalanced as a result of climate change and human activity. This is according to a new report by the World Meteorological Organization (WMO), which contains a comprehensive assessment of global water resources. Droughts and extreme precipitation events are taking a heavy toll on life and the economy. The melting of snow, ice and glaciers has increased dangers such as flooding and threatens long-term water security for many millions of people.
Measurement of water resources
And yet far too little is known about the true state of the world's freshwater resources. We cannot manage what we do not measure, says the WMO report on the state of global water resources 2022, which calls for a fundamental change in policy.
Monitoring, data sharing, transboundary cooperation and assessment of water resources must be improved - and investment must be increased to make this possible. This is essential to help society deal with the increasing water extremes of too much or too little water, according to the report.
The WMO report on the state of global water resources 2022 builds on a pilot report published last year. It contains more comprehensive information on key hydrological variables such as groundwater, evaporation, runoff, terrestrial water storage, soil moisture, cryosphere (frozen water), inflows to reservoirs and hydrological disasters. It integrates field observations, satellite-based remote sensing data and numerical modeling simulations to assess water resources on a global scale.
"This WMO report provides a comprehensive and consistent overview of global water resources and shows the impact of climate, environmental and societal changes," says WMO Secretary-General Prof. Petteri Taalas.
"The glaciers and the ice cover are retreating before our eyes. Rising temperatures have accelerated - and also disrupted - the water cycle. A warmer atmosphere stores more moisture. This results in much heavier rainfall and flooding. And at the opposite extreme, there is more evaporation, drier soils and more intense periods of drought," he says.
"The overwhelming majority of disasters are water-related, which is why water management and monitoring are at the heart of the global Early Warnings for All initiative. Many of the countries prioritized for action under the Early Warnings for All initiative were hit by severe floods or droughts in 2022. Not a single country had timely and accurate hydrological data that would have supported evidence-based decision-making and early action," said Prof. Taalas.
"This report is a call to action for increased data sharing to enable meaningful early warnings and for a more coordinated and integrated water management policy that is an integral part of climate action," he says.
Currently, 3.6 billion people do not have sufficient access to water for at least one month a year, and this figure is expected to rise to more than 5 billion by 2050, according to UN Water.
The most important findings of the report
The WMO figure shows the average runoff for 2022 compared to the historical average for the period 1991-2020
Hydrological variables
The report provides an independent and consistent quantitative assessment of water resources in large river basins compared to the long-term average for different variables such as river discharge, groundwater, evaporation, soil moisture, reservoir inflow, etc.
Drain
In 2022, there were deviations from normal runoff conditions in over 50% of the world's catchment areas. Most of these areas were drier than normal, while a smaller percentage of catchments were above or well above normal conditions. This was similar to 2021.
Water reservoirs
More than 60% of the large water reservoirs recorded a below-average or normal inflow, which poses a challenge for the water supply of all users in an increasingly changeable climate.
Soil moisture and evaporation
Throughout 2022, there were anomalies in soil moisture and evaporation that coincide with the runoff conditions in the rivers. For example, Europe experienced increased evaporation and a decrease in soil moisture and river runoff during the summer due to a major heat wave and drought. This not only led to problems in agriculture, but also to the shutdown of power plants due to a lack of cooling water.
Weather phenomena
The change from La Niña in 2022 to El Niño in 2023 is likely to have a major impact on the water cycle, which will be analyzed in next year's report.
Cryosphere (glaciers, ice shelves, ice and snow)
Asia
The third pole, which includes the Tibetan Plateau, the Himalayas, the Karakoram, the Hindu Kush, the Pamirs and the Tien Shan Mountains, is vital for the water supply of almost 2 billion people. From 2000 to 2018, the total glacier mass balance decreased by more than 4 percent. The snow cover has decreased significantly and the volume of glacial lakes has increased sharply.
This has had an impact on the discharge of the Indus, Amu Darya, Yangtze and Yellow Rivers and shows the increasing influence of climate change on this region.
Alpine region
In 2022, the snow cover in the Alps, which are crucial for feeding large rivers such as the Rhine, Danube, Rhone and Po, remained well below average. There was an unprecedented loss of glacier mass in the European Alps.
South America
In the subtropical Andes, winter snowfall has been steadily declining since 2009, affecting water supplies to cities throughout Chile and western Argentina. Although slightly above-average snowfall was recorded in some areas in 2022, important water catchment areas, especially on the Argentinian side, still had below-average conditions, leading to persistent water restrictions in populous urban centers.
Water-related disasters
Europe
In the summer of 2022, many parts of Europe were hit by severe droughts, which made transportation on rivers such as the Danube and Rhine difficult and affected the generation of electricity from nuclear power plants in France due to a lack of cooling water.
USA
Navigation on the Mississippi River in the USA was affected by the extremely low water levels caused by a prolonged drought in the USA.
South America
In South America, the La Plata catchment area has been suffering from a prolonged drought since 2020. In 2022, this led to a significant drop in hydropower generation due to the low water levels in the rivers. In Paraguay, there were several cases in 2022 where no water was supplied.
China
The severe drought in the Yangtze catchment area in China meant that river discharge, reservoir inflow and soil moisture were well below average.
Horn of Africa
The prolonged drought led to a major humanitarian crisis in the Horn of Africa. In contrast, the Niger Basin and large parts of South Africa recorded above-average river discharges, which led to major flooding in 2022.
Pakistan
The Indus river basin in Pakistan was hit by a mega flood that killed at least 1,700 people, affected 33 million people and caused an estimated economic loss of more than 30 billion US dollars. A heatwave at the beginning of the year led to increased melting of the glaciers and thus to a rise in river levels, which then swelled further due to heavy monsoon rainfall, which was more than double the average in July and August.
The figure shows selected notable hydrological events with major impacts around the world in 2022; the circles indicate floods (blue) and droughts (red)
