Most of the world was drier than normal in 2021, with “cascading effects on economies, ecosystems and our daily lives,” the UN World Meteorological Organization (WMO) said on Tuesday.
According to the agency’s first report on world water resources, areas that were unusually dry included the Rio de la Plata area of South America, where persistent drought has affected the region since 2019.
In Africa, major rivers such as the Niger, Volta, Nile, and Congo had below-average water flow in 2021. The same trend was observed for rivers in parts of Russia, Western Siberia, and Central Asia.
On the other hand, there were above-normal river volumes in some basins in North America, the northern Amazon, and South Africa, as well as in the Amur River basin of China and northern India.
In Africa, rivers including the Niger, Volta, Nile, and Congo all had below-normal discharge in 2021, along with parts of Russia, Western Siberia, and Central Asia.
The WMO said that 3.6 billion people have inadequate access to water for at least one month of the year and that this is expected to rise to more than five billion by 2050.
climate crisis
“The impacts of climate change are often felt through water: more intense and frequent droughts, more extreme floods, more erratic seasonal rainfall and accelerated melting of glaciers, with cascading effects on economies, ecosystems and all aspects of our daily lives,” the WMO said. General Secretary Prof. Petteri Taalas.
“And yet there is insufficient understanding of changes in the distribution, quantity and quality of freshwater resources.”
The report on the state of the world’s water resources “aims to fill that knowledge gap and provide a concise overview of water availability in different parts of the world,” he added.
“This will inform investments in climate mitigation and adaptation, as well as the United Nations campaign to provide universal access over the next five years to early warnings of hazards such as floods and droughts.”
Water, water everywhere
Between 2001 and 2018, UN-Water reported that a staggering 74% of all natural disasters were related to water.
The recent UN climate change conference, COP27, in Egypt, urged governments to further integrate water into adaptation efforts, the first time water was referenced in a COP outcome document in recognition of its critical importance, noted the WMO.
The first edition of the report looks at discharge (the volume of water flowing through a river channel at a given time) and also assesses terrestrial water storage, in other words, all water on the surface and subsurface of the earth and the (frozen) cryosphere. Water).
The report highlights a basic problem: the lack of accessible verified hydrological data.
The WMO Unified Data Policy seeks to accelerate the availability and sharing of hydrological data, including information on transboundary river and river basin discharges.
land cover
Other than river flow variations, total terrestrial water storage was classified as below normal for the West Coast of the United States, central South America and Patagonia, North Africa and Madagascar, Asia Central and Middle East, Pakistan and North India.
It was above normal in Central Africa, northern South America, specifically the Amazon basin, and northern China.
“In general, the negative trends are stronger than the positive ones,” the WMO warned, with several hotspots emerging, including Patagonia, the Ganges and Indus headwaters, as well as the southwestern US.
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cryosphere
The cryosphere, meaning glaciers, snow cover, ice caps and, when present, permafrost, is the world’s largest natural freshwater reserve.
“Changes in cryosphere water resources affect food security, human health, ecosystem integrity and maintenance, and cause significant impacts on economic and social development,” the WMO said, sometimes causing flooding. of rivers and flash floods due to overflows of glacial lakes.
With rising temperatures, annual runoff from glaciers generally increases at first, until a tipping point is reached, often called “peak water,” at which runoff decreases.
Long-term projections of glacier runoff and the timing of peak water are key inputs for long-term adaptation decisions, the WMO added.
