Energy-based sustainability index

Many publications use an absolute measure that denotes water security, frequently referring to an index that identifies a threshold of 1,700 CM per capita per year of renewable water, based on estimates of water requirements in the household, agricultural, industrial, and energy sectors as well as the needs of the enviromnent. Countries whose renewable water supplies cannot sustain this figure experience water stress. When supply falls below 1,000 m per capita per year, a country is said to experience water scarcity, and below 500 m per capita per year, absolute scarcity. However, these terms are easy to misinterpret, because they do not take into account possibilities for trade in agricultural products, efficiency of water use in agriculture, and other variables, and thus obscure the primacy of economic demand rather than physical need in determining water use [3-5]. 

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