Four Billion People Suffer From Severe Water Scarcity Worldwide

Nearly 66 percent of the world's human population suffers from insufficient access to fresh water for at least one month out of the year. This estimate, which equates to about four billion people, is far greater than scientists thought.

Previously it was believed that that between 1.7 and 3.1 billion people lived with moderate to severe water scarcity for at least one month of year. However, in the latest study, led by Dr. Arjen Hoekstra of the Netherlands' University of Twente, researchers used a high-resolution computer model that is both more precise and comprehensive.

Rather than assessing water scarcity on an annual basis, Hoekstra and his team are the first to examine people's water footprint from month to month, and then compare it to the monthly availability of water. This novel approach allowed researchers to better assess how widespread water scarcity is across the globe, taking into consideration updated climate records, population density, irrigation and industry.

"Up to now, this type of research concentrated solely on the scarcity of water on an annual basis, and had only been carried out in the largest river basins," Hoekstra said in a news release. "That paints a more rosy and misleading picture, because water scarcity occurs during the dry period of the year."

Severe water scarcity is defined as the depletion of water in a certain area. This means that groundwater levels are falling, lakes are drying up, less water is flowing in rivers, and water supplies for industry and farmers are threatened.

"The fact that the scarcity of water is being regarded as a global problem is confirmed by our research," Hoekstra added. "For some time now, the World Economic Forum has placed the world water crisis in the top three of global problems, alongside climate change and terrorism."

The study identifies the growing populations, consumption practices, and climate change as the leading causes of severe scarcity and decreased water quality. For instance, half of those suffering from water scarcity are in the world's two most populous countries -- India and China -- where demand is high.

Other problem areas include Mexico, the western U.S., northern and southern Africa, southern Europe, the Middle East, and Australia. It is in these areas that people feel the direct impacts of water scarcity.

The consequences of water scarcity can result in economic losses due to crop failure, limited food availability, loss of environmental biodiversity and heightened global conflict. What's worse is that groundwater supplies may be permanently depleted if over-pumped.

"We are continuing with the next phase of our research, where the models are even more advanced, where we will understand the problem with even greater precision, and where we will be putting forward solutions," Hoekstra concluded.

The study was recently published in the journal Science Advances. 

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