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FACTS ABOUT VIRTUAL WATER

The concept of virtual water emerged in the early 1990s and was first defined by Professor J.A. Allan as the 'water embedded in commodities'. The water used in the production process of an agricultural or industrial product is called the 'virtual water' contained in the product

The amount of virtual water imported by a country is a measure of the degree to which the country depends on the international market for its food supply

Virtual water is an essential tool in calculating the real water use of a country, or its water footprint, which is equal to the total domestic use, plus the virtual water import, minus the virtual water export of a country

140 litres of water is the amount of water needed to produce 1 cup of coffee

550 litres is the amount of water needed to produce enough flour for one loaf of bread (400 grams)

The production of 1 litre of milk requires 1,000 litres of water.

The production of 1 kilogram of:

  • rice requires 3,000 litres of water
  • maize requires 900 litres of water
  • wheat requires 1,350 litres of water
  • beef requires 1,6000 litres of water

(Figures extracted from the 'Water Footprint website, developed by UNESCO-IHE)

Source: UNESCO Water Portal, February 2005