ScienceDaily: There are four billion people worldwide who are affected by severe water scarcity for at least one month a year. That is the conclusion of University of Twente Professor of Water Management, Arjen Hoekstra, after many years' extensive research. This alarming figure is much higher than was previously thought. His ground-breaking research was published in Science Advances. Professor Hoekstra's team is the first research group in the world to identify people's water footprint from month to month and...