The challenges and threats of water scarcity to dryland populations are set to increase in magnitude and scope. As the world’s population has swollen to well over 6 billion people, some countries have already reached the limits of their water resources. With the existing climate change scenario, almost half the world’s population will be living in areas of high water stress by 2030, including between 75 million and 250 million people in Africa. In addition, water scarcity in some arid and semi-arid places will displace between 24 million and 700 million people (WWDR 2009).