The Impacts of "Virtual Water"
Link: Scientist who invented "virtual water" wins prize
The Stockholm International Water Institute awarded Professor John Anthony Allan (University of London, Britain) the 2008 Stockholm Water Prize for introducing the concept of "virtual water", a calculation method that takes into account the water embodied in foods and industrial products throughout their lifecycle. For example, the 140 litres of water consumed to grow, process, package and ship the coffee beans required for a cup of water far outweighs the water that goes into the coffee maker.
Wikipedia has a synopsis of the "virtual water" concept and lists the embodied water in a range of agricultural, household and industrial products. For example:
- 1 kilogram of beef: 15,000 litres of water
- 1 kilogram of jeans: 10,850 litres of water
- a 1,100 kilogram car: 400,000 litres of water
- green water: rainwater evaporation
- blue water: surface or ground water evaporation
- grey water: water the becomes polluted during the process
Although "virtual water" can be used as a way of assessing the impact of different products on water resources, Allan's developed the concept to explain why water scarcity in regions such as the Middle East had not led to 'water wars (Watersheds and Problemsheds: Explaining the Absence of Armed Conflict Over Water in the Middle East). Imports of products, particularly agricultural produce with a high embodied water content can represent a significant import of "virtual water", reducing the stress on local water supplies. According to Virtual Water, 15% of the world's water usage is for export, with USA, Canada and Thailand the leading exporters and Sri Lanka, Japan and Netherlands the leading importers. Allan argues "virtual water" should guide policy decisions, such as allocating water to products that "bring a sound return to water as well as sound returns to the economy" and increasing productive efficiency.
