Water scarcity is the lack of sufficient available water resources to meet the demands of water usage within a region. Water shortages may be caused by climate change, such as altered weather patterns which include droughts or floods, increased pollution, increased demand and overuse of water. There are 4 billion people worldwide who are affected by water scarcity at least one month a year. That is the conclusion of University of Twente (Netherlands) Professor of Water Management, Arjen Hoekstra.
Until now, it had always been assumed in the scientific community that 2 to 3 billion people were affected by severe water scarcity. "Previous research looked at the availability of water on an annual basis, but that paints a more rosy and misleading picture, because water scarcity occurs during the dry period of the year," explains Hoekstra. In his research, he describes for each place the number of months in a year that people are affected by severe water scarcity. That varies from zero to twelve months per year.
Of the four billion people referred to, a large proportion feel the effects of water scarcity directly. Particularly in Mexico, the western U.S., northern and southern Africa, southern Europe, the Middle East, India, China, and Australia, households, industries and farmers regularly experience water shortages. In other areas, water supplies are still fine but are at risk in the long-term.