According to the first in a series of United Nations reports on how climate change is affecting the world’s water resources, 5 billion people, or about two-thirds of the world’s population, will face water scarcity for at least one month by 2050.
This World Meteorological Organization assessment, released Tuesday, includes forecasts for river flows, floods and droughts for each continent. It offered mixed findings but warned that water security around the world would become increasingly uneven. Some places, such as the Rio San Francisco Basin in Brazil, face a challenging future; others, including the Great Lakes region of the United States, fare better.
“The impacts of climate change are often felt through water – more intense and frequent droughts, more extreme floods, less erratic seasonal rainfall and accelerated melting of glaciers – on economies, ecosystems and every aspect of our daily lives Cascading effects,” WMO Secretary General Petteri Taalas said in a release. “However, changes in the distribution, quantity and quality of freshwater resources are poorly understood.”
The 36-page report “aims to fill this knowledge gap and provide a brief overview of water availability in different parts of the world,” he added.
Findings will also help guide climate adaptation and mitigation investments and inform a United Nations campaign to universally use early hazard warning systems for climate hazards such as floods and droughts.
As with other climate change phenomena, there will be losers and winners, the authors write, but “in general, negative trends are stronger than positive ones.”
In the United States, for example, ongoing droughts are expected to take a greater toll on water security in the West. However, due to its proximity to the five largest freshwater lakes in the world, the Great Lakes region has relatively high water security.
Other regions projected to have above-average water storage capacity by 2050 include the Niger Basin in West Africa, the Great Rift Valley and the northern Amazon Basin, the scientists said.
Instead, the report identified several “hotspots with negative trends” in global water storage, including the Rio San Francisco Basin in Brazil, Patagonia in southern South America, and the source and flow of the Ganges in the Himalayas in northern India. Indus River in the area. Tibet to the Arabian Sea.
Rapid melting of snow and ice at high altitudes has “significant implications” for global water security, as does the heavy use of groundwater for irrigation, a problem exacerbated by drought and shrinking surface water reservoirs, the researchers said.
Another key finding is that, based on 30-year hydrological averages, the global area with below-average river flow in 2021 is approximately twice as large as the area with above-average river flow. Scientists attribute 2021’s conditions to climate change and a La Niña event, a pattern of atmospheric oscillations characterized by wide variations in Pacific water temperatures.
Between 2001 and 2018, the United Nations reported that 74% of all natural disasters were water-related – prompting participants at the recent UN climate conference in Egypt to further Incorporating water into adaptation efforts. Officials said this is the first time water has been mentioned in a COP document that recognizes its importance.
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