From CopperWikimeat, wheat and other produce also takes into account the water used locally to produce such livestock and crops. Thus, virtual water reflects such indirect water imports.
In the 1980s Israeli economists realized that every time water-intensive oranges or avocados were exported from their semi-arid country, scarce Israeli “virtual water” was also being exported. To them it did not make economic sense.
Though the term "virtual water" was finally coined at a seminar at the School of Oriental and African Studies (SOAS), University of London in about 1993, the genesis of the phrase can be traced to the then Israeli concern. The earlier description of this phenomenon as "embedded water" by Professor J.A. Allan, in his own words, "did not capture the attention of the water managing community".
 Why should I be aware of this?
Carbon footprint, or a measure of how much carbon dioxide a person produces by lifestyle choices, is today a well known concept. Equal in importance, though not so well known is the concept of water footprint or virtual water or average annual water consumption. This is a measurement of how much water a person produces by his lifestyle choice.
 All about virtual water
Every T-shirt we all love to wear requires 25 bathtubs of water to produce. When this T-shirt is exported it also amounts to exporting 25 bathtubs of “virtual water” to that country. If the importer is a water-strapped country it saves in the process 25 bathtubs of virtual water it would otherwise have used in making the T-shirt indigenously.
 National Water Footprint
A nation’s water footprint shows the total volume of water that is used to produce the goods and services consumed by the inhabitants of the nation. Since not all goods consumed in one particular country are produced in that country, the water footprint consists of two parts: use of domestic water resources and use of water outside the borders of the country.
The water footprint of a product varies depending on where it is produced. Virtual water content of cotton will be 5,404 m3/ton if produced in China but 21,563 m3/ton if produced in India. The difference depends on the amount of rainfall, the water availability in the soil and the amount of water needed for irrigation.
The water footprint of a nation is linked to the dietary habits of people. High meat consumption in a country brings about a large water footprint. Also if there is a large quantity of food coming from irrigated land it means there is higher footprint. Nations with warm climate zones account for much higher water print as food production in these countries require higher water consumption.
 Virtual Water Consumed by Different Countries
There are variations in the virtual water consumption in different countries. The variation is caused by differences in personal consumption of food, goods and services. In the UK it is 1245 m3/person/yr, in the US 2483 m3/person/yr which is three times the level in China.
Water import dependency in the UK is 70% compared to 79 percent in Switzerland, 80 percent Belgium, 72 percent in the Netherlands and 37 percent in France.
- The water footprint of China is about 775 cubic meters per year per capita. Only about 3% of the Chinese water footprint falls outside China.
- Japan with a footprint of 1100 cubic meter per year per capita, has about 60% of its total water footprint outside the borders of the country.
- The USA’s water footprint is 2600 cubic meter per year per capita
 Individual Water Footprint
The water footprint of an individual is defined as the total amount of freshwater that is used to produce the goods and services that the individual consumes as a result of its own consumption pattern and the country of residence. It is a useful indicator for showing food diet and consumption patterns.
- 1 cup of coffee needs 140 liters of water
- 1 liter of milk needs 800 liters of water
- 1 kg of wheat needs 1100 liters of water
- 1 kg of rice needs 2300 liters of water
- 1 kg maize needs 900 liters of water
- The production of one kilogram of beef requires 22 thousand liters of water.
- To produce one cup of coffee we need 140 liters of water.
It is clear that moderating our diets especially in the developed world could make much water available for other purposes. In semi-arid and arid areas, knowing the virtual water value of a good or service can be useful towards determining how best to use the scarce water available.
 Virtual Water Trade
The global virtual-water trade is estimated at around a thousand cubic kilometers a year, or 20 Niles Rivers. Every year more virtual water flows into the MENA region than what Egypt gets from the Nile for agriculture.
Middle East and North Africa, or what is known as the MENA region, was the first area in history to run out of water in the 1970s. Drinking water takes up one cubic meter per year per person in this region. This takes up a greater part of the available supply. Further 1,000 cubic meters of low quality water is needed for food each individual needs in a year. The MENA region has been importing 40 million tons of cereals and flour annually since the 1980s.
 Correcting the Water Imbalance
Import of real water is too expensive. To correct the water imbalance water scarce countries can import high water consuming products while exporting low water consuming products. This also enables water scarce countries to save water for other purposes.
Many countries import food from around the world and thereby qualify as importers of virtual water. If there is water scarcity in the importing country, this represents real water saving and reduced pressure on its water resources. The exporting country this way utilizes its abundant water resources to improve global water use efficiency. By this measure no country can ignore any specific country’s water problem as shortage or contamination of water in any country is likely to affect another country at any given point of time.
 Advantages to Developing Countries
The developing countries should ensure that the water saved by importing virtual water is utilized in development work such as improving sanitation. The exporting countries should ensure that its exports do not endanger the health of its citizens by exporting. Currently, some of the biggest net exporters of virtual water are the US, Canada, Thailand, Argentina, India, Vietnam, France and Brazil. Big net importers of virtual water include Sri Lanka, Japan, the Netherlands, South Korea, China, Spain, Egypt, Germany and Italy.
USA, Canada, Brazil and Argentina are greater water exporters particularly in the form of meat while China, with its intensive agriculture, is a major importer of meat.
 What can I do?
Pledge to Fight Water Scarcity
At the first Asia-Pacific Water Summit was recently held in the hot spring resort city of Beppu, Japan, representatives 36 countries and territories pledged to reduce by half the number of people who lack access to safe drinking water by 2015, and resolve the problem totally by 2025.
While The Asia Pacific region is flood and tsunami prone, water shortages and pollution pose the single gravest danger. According to a United Nations report, about 60 percent of the 1.2 billion people worldwide with no access to safe drinking water, about 60 percent dwell in the Asia-Pacific zone. Likewise, 70 percent of the 2.4 billion lacking access to toilets or other hygienic facilities live in the Asia-Pacific region.
A part of this imbalance can be set right by trade in virtual waters.
- The production of 1 kilogramme of rice requires 2300 litres of water.
- One kilo of maize requires 900 litres of water.
- One kilo of beef requires 22000 litres of water.
- One litre of milk requires 800 litres of water.
- 140 litres of water are needed to produce 1 cup of coffee.
- The water footprint of a product varies depending on where it is produced. Virtual water content of cotton will be 5,404 m3/ton if produced in China but 21,563 m3/ton if produced in India. The difference depends on the amount of rainfall, the water availability in the soil and the amount of water needed for irrigation.
- The per capita consumption of virtual water contained in our diets varies according to the type of diet, from 1 m3/day for a survival diet, to 2.6 m3/day for a vegetarian diet and over 5 m3 for a United States-style meat-based diet
- Virtual Water
- Virtual water trading
- It's called `virtual water'...
- How to profit from the world's water crisis?
 Additional Information
- Refer to National Water Footprint calculator
- See Water Poster. You can also order a copy online.
- Refer to Individual Water Footprint Calculator