What is 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. Producing goods and services requires water; the water used to produce agricultural or industrial products is called the virtual water of the product.    Water-scarce countries are using the new concept of 'virtual water' -- the amount of water needed to create goods -- to determine their agricultural and industrial production strategies. Virtual water refers to the water required in the production of a good or service. For instance, it takes more or less 1,200 cubic meters of water to produce one metric tonne of wheat. The water is said to be virtual because once the wheat is grown, the real water used to grow it is no longer actually contained in the wheat. Thus virtual water is the amount of water that is embedded in food or other products needed for its production. Trade in virtual water allows water scarce countries to import high water consuming products while exporting low water consuming products and in this way making water available for other purposes. "When you consume one kilo of grain, you are in effect also consuming the one thousand liters of water needed to grow that grain, when you consume one kilo of beef, you are consuming the 13,000 liters of water needed to produce that amount of meat, and this is the hidden or 'virtual water'," says Daniel Zimmer, Director of the World Water Council.

Virtual water is an indicator of water use   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. A nation’s water footprint is a useful indicator of the demand it places on global water resources.  At the individual level, the water footprint is equal to the total virtual water content of all products consumed. A meat diet implies a much larger water footprint than a vegetarian one, at an average of 4,000 litres of water per day versus 1,500. Being aware of our individual water footprint can help us use water more carefully.  The flow of virtual water throughout the world  Trends and products   Trade in virtual water has steadily increased over the last forty years: about 15% of the water used in the world is for export, in virtual form.  Since, at the global level, agriculture is the largest economic sector in terms of water use, trade in agricultural products is the main component of trade in virtual water.   According to A.Y. Hoekstra, an expert from the UNESCO-IHE Institute: 67% of the global virtual water trade is related to international trade of crops;  23% is related to trade of livestock and livestock products;  10% is related to trade of industrial products.    Wheat represented 30% of the total volume of crop-related virtual water trade between nations in the period 1995-1999, followed by soybean (17%) and rice (15%) (see table on the left). The trade of beef is also important to global virtual trade.    Is virtual water strategy: a solution for water-poor countries?   Some experts argue that the importing of virtual water (via food or industrial products) can be a valuable solution to water scarcity, especially for arid countries that depend on irrigation to grow low-value food with high water needs.    In Asia, people consume an average of 1,400 liters of 'virtual water' per day, whereas in Europe and North America, people consume about 4,000 liters of 'virtual water' per day. Some 70 percent of all water utilized by humans goes into food production.  "The magnitude of this variation demonstrates that diet is very important for water consumption."  Calculations show that nearly 20 percent of the water that is consumed by agriculture is traded to other countries in the form of the food and other products that result. This is quite a big figure, since five trillion cubic meters of water per year is used for agriculture, and out of that one trillion is involved in trade between countries."   Rajasthan  where groundwater is being non-sustainable exploited knowing the virtual water value of a good or service can be useful towards determining how best to use the scarce water available.  Since Rajasthan  is water-scarce, the water that is 'saved' can be used towards other ends. Even water-scarce countries like Israel discourage the export of oranges (relatively heavy water guzzlers) precisely to prevent large quantities of water being exported to different parts of the world. Israel and Jordan have formulated policies to reduce or abandon the export of water-intensive products. Exports are largely limited to crops that yield a relatively high income per cubic metre of water consumed.  But India, where several forces and compulsions will determine whether virtual water trade is indeed a solution at all. Their socio-economic and other societal compulsions may not allow it. When a country opts consciously for virtual water imports to alleviate its water problem, it is also choosing to alter its cropping patterns in a significant way. This could deprive farmers of their livelihoods unless alternatives are developed in terms of other crops or employment avenues.    At present the need first to manage efficiently the real water sources. Inefficient use of irrigation water leads to low water productivity even in crops that have high water use efficiency. Farmers should be encouraged and educated to adopt such crops which give high returns and less water. Many oilseed and fruit crops have high water efficiency - that is, they require less water but give higher returns.

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