Five billion people, or around two-thirds of the world’s population, will be affected by water scarcity for at least a month by 2050, according to the first in a series of reports from the United Nations on the impact of climate change on the world’s water resources.
The assessment published on Tuesday by the World Meteorological Organization includes forecasts for river courses, floods and droughts on all continents. It offered a mixed bag of insights but warned that water security was becoming increasingly unequal around the world. Some places, like the Rio São Francisco basin in Brazil, face a challenging future; others, including the Great Lakes region of the United States, are in better shape.
“The impacts of climate change often come through water – more intense and frequent droughts, more extreme floods, more erratic seasonal rainfall and accelerated melting of glaciers – with cascading impacts on economies, ecosystems and all aspects of our daily lives,” said the WMO Secretary – General Petteri Taalas said in a press release. “Nevertheless, there is a lack of understanding of changes in the distribution, quantity and quality of freshwater resources.”
The 36-page report “aims to fill this knowledge gap and provide a concise overview of water availability in different parts of the world,” he added.
Findings will also help guide investment in climate adaptation and mitigation and inform the United Nations campaign to provide universal access to early warning systems for climate-related disasters such as floods and droughts.
As with other climate change phenomena, there will be losers and winners, however, the authors wrote: “Overall, the negative trends are stronger than the positive ones.”
In the United States, for example, the ongoing drought is expected to take an even greater toll on water security in the west. However, the Great Lakes region will have relatively high levels of water security due to the region’s proximity to five of the world’s largest freshwater lakes.
Other regions projected to have above-average water storage capacities by 2050 include West Africa’s Niger Basin, the East African Rift Valley and the northern Amazon Basin, scientists said.
Conversely, the report identified several global “hotspots with negative trends” in water storage, including Brazil’s Rio São Francisco basin, Patagonia in southern South America, the headwaters of the Ganges in the Himalayan mountains of northern India, and the Indus River, which flows from Tibet to Tibet to the Arabian Sea.
Researchers said the rapid melting of snow and ice in high-altitude regions is having “a significant impact” on global water security, as is heavy use of groundwater for irrigation, a problem exacerbated by drought and shrinking surface reservoirs.
Another key finding was that the global area of below-average discharge in 2021 was about twice the size of the global area of above-average discharge, based on 30-year hydrological mean values. Scientists attributed the 2021 conditions to both climate change and a La Niña event, an atmospheric oscillation pattern characterized by large water temperature swings in the Pacific Ocean.
Between 2001 and 2018, the United Nations reported that 74 percent of all natural disasters were water-related – prompting participants at the recent UN Climate Change Conference in Egypt to include water more in adaptation efforts. Officials said it is the first time water has been mentioned in a COP document acknowledging its critical importance.
E&E News reprinted with permission from POLITICO, LLC. Copyright 2022. E&E News provides important news for energy and environmental professionals.