Severe water scarcity affects at least two-thirds of the world's population, or about 4 billion people, according to a new study.
These people experience severe water scarcity at least one month a year, and the number is far higher than the 1.7 billion to 3.1 billion people suggested by previous research. Nearly half of the people affected are in China and India.
Other countries where large numbers of people are affected by severe water scarcity for at least part of the year include Bangladesh, Mexico, Nigeria, Pakistan and the United States (mostly in western states such as California and southern states such as Texas and Florida), the study found.
The rising worldwide demand for fresh water is being driven by a growing population, increased agricultural irrigation, higher living standards and changing consumption patterns, according to the researchers led by Mesfin Mekonnen and Arjen Hoekstra of the University of Twente in the Netherlands.
They said the threat can be reduced by placing limits on water consumption, boosting water use efficiency, and improving sharing of fresh water resources.
The study was published Feb. 12 in the journal Science Advances.
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M. M. Mekonnen et al. Four billion people facing severe water scarcity, Science Advances (2016). DOI: 10.1126/sciadv.1500323