Newspaper article The Christian Science Monitor

Four Billion People Face Water Scarcity: Why an Accurate Figure Is Important

Newspaper article The Christian Science Monitor

Four Billion People Face Water Scarcity: Why an Accurate Figure Is Important

Article excerpt

Fresh water on Earth is scarce and getting scarcer - we know that. In 2015 the World Economic Forum ranked "water crises" as the top risk facing the planet.

But authors of a recent report published Friday in the journal Science Advances say previous studies have underestimated the severity of water scarcity around the world. Instead of impacting around two billion people as researchers previously suggested, it's more along the lines of four billion, say Dr. Mesfin Mekonnen and Dr. Arjen Hoekstra at the University of Twente in Enschede, Netherlands.

So how has previous research been so off? It relied on annual averages, say the authors.

"Most of the previous water scarcity studies are done on an annual basis, which hides the actual variability within a year," co- author Dr. Mekonnen, a postdoctoral researcher at the University of Twente, tells The Christian Science Monitor in an email Thursday. To understand water scarcity on the global level, Mekonnen and Hoekstra assessed local "blue water scarcity," or the amount of freshwater that is withdrawn and not returned, on a monthly level.

But these four billion people are not facing water scarcity all year round, notes Mekonnen, instead it's more along the lines of one month a year.

"When you average over the whole year, you miss that one month where [a] large number of people face water scarcity," says Mekonnen. "Before we thought only [a] small number of people face severe water scarcity," but a larger population's few, difficult months were skewing the annual average.

"Water scarcity generally occurs only during part of the year, when there is a mismatch between water availability and demand," explains Mekonnen. Only half a billion people actually experience water scarcity for the entire year.

The truth about water scarcity's impact is important, say the authors, because informed consumers are more likely to "demand transparency about the water consumption and pollution underlying consumer products from business and governments," Dr. …

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