One-fifth of the world’s population are at risk of severe water shortages
Researchers at the University of California, Irvine have determined that nearly 20 percent of the global population lives in a stressed water basin where climate change could threaten water availability for agriculture, industry, and for everyday use.
The investigation was focused on trends in global water usage from 1980 to 2016, with an emphasis on what is known as inflexible consumption. Crop irrigation, cooling thermal power plants, livestock, and humans all have a demand for water that is inflexible.
“Many studies evaluating water scarcity have mainly centered on the share of the available supply being consumed by humans, but this ignores the fact that some uses are more flexible or productive than others,” said study lead author Yue Qin. “By looking at how water is actually used, we can begin to see what water is really difficult to do without and if there are any opportunities for savings in other areas.”
The scientists developed a water stress index that takes into account the scarcity, flexibility, and variability of global water supplies. The study, which was focused on watersheds on six continents, pinpointed numerous hot spots where a drought or heat wave could put a major strain on reserves. The researchers also identified numerous opportunities to conserve resources through new technologies and better management practices.
The investigation showed that the top 10 percent of the most stressed river basins support about 19 percent of the world’s population, 19 percent of thermal electricity generation, and one-third of irrigated agricultural production. Over the course of the 37-year study period, there was a significant increase in water stress for the worst-impacted regions.
According to the study, Asia faces an even greater dilemma due to their high stress indices combined with the total human and livestock population, reservoir capacity, electricity generation, and production of irrigated crops. North America is in the same predicament, but to a lesser degree. These areas are particularly vulnerable to shocks triggered by droughts and heat waves.
“The new index tells us where water issues are greatest and for what reasons, so decisions now don’t limit our options and ability to be resilient in the future,” said Thomas Torgersen, who is a program director in the National Science Foundation’s Division of Earth Sciences, which funded the research.
The scientists evaluated the productivity and flexibility of water use in specific basins, and discovered that the Nile basin in Africa and the Tigris-Euphrates and Lake Balkhash basins in Asia all have high water stress indices and elevated consumption. The study authors determined that water could be saved by switching from cooling power plants with fresh water to dry cooling technologies. They found that this strategy could decrease cooling water use in the Lake Balkhash basin by 95 percent.
“Given the limited political capital and resources when you’re developing new technologies and policies, where do you focus those efforts for the most potential benefit?” said co-author Professor Julie Zimmerman. “We can’t solve these problems in isolation. This study reinforces the linkages between these systems and why we need to be holistic in our approaches.”
The study is published in the journal Geophysical Research Letters.
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Image Credit: Steven Davis / UCI