Water scarcity is among the main problems to be faced by many societies and the World in the XXIst century. Water use has been growing at more than twice the rate of population increase in the last century, and, although there is no global water scarcity as such, an increasing number of regions are chronically short of water.
Water scarcity is both a natural and a human-made phenomenon. There is enough freshwater on the planet for six billion people but it is distributed unevenly and too much of it is wasted, polluted and unsustainably managed.
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Vital Water Graphics. UNEP
Human Development Report 2006. UNDP, 2006
Coping with water scarcity. Challenge of the twenty-first century. UN-Water, FAO. 2007 Water Scarcity and the MDGs
The way water scarcity issues are addressed impacts upon the successful achievement of most of the Millennium Development Goals.
Water stress versus water scarcity
Hydrologists typically assess scarcity by looking at the population-water equation. An area is experiencing water stress when annual water supplies drop below 1 700 m3 per person. When annual water supplies drop below 1 000 m3 per person, the population faces water scarcity, and below 500 cubic metres "absolute scarcity".
Water scarcity is defined as the point at which the aggregate impact of all users impinges on the supply or quality of water under prevailing institutional arrangements to the extent that the demand by all sectors, including the environment, cannot be satisfied fully. Water scarcity is a relative...