Figure 6.6: Global freshwater availability and stress. Freshwater stress and scarcity occur when so much water is withdrawn from rivers, lakes, and aquifers that not enough water remains to meet human and ecosystem requirements for sustainability.

[Source consulted: United Nations Environmental Programme, Vital Water Graphics: An Overview of the State of the World’s Fresh and Marine Waters, 2nd ed., 2008, at http://www.unep.org/dewa/vitalwater/article69.html]