Fresh water scarcity: An introduction to the problem - Christiana Z. Peppard
Fresh water is essential for life -- and there's not nearly enough of it for the world right now. Why is that, and what could we do? Christiana Z. Peppard lays out the big questions of our global water problem. And no, shorter showers are not the answer.
Watch this video : http://ed.ted.com/lessons/fresh-water-scarcity-an-introduction-to-the-problem-christiana-z-peppard