The amount of water needed varies with crops and depends from place to place, on local productivity and conditions of available water supply through rainfall or irrigation. Once the product is harvested and becomes available on the market, the water embedded in the product changes status from ‘real’ water to ‘virtual’ water.
Today is World Water Day. On average, we consume 923 gallons* of water a day. Some of it is used for household needs and industrial goods like clothes. But most of it, 92%, is the virtual water embedded in the food we grow, through the water used to irrigate crops and to grow animal feed, and as drinking water for farm animals.
PNAS Study: Population Growth Will be Constrained by the Limits of Trading Virtual Water (Food) -- The study by the Proceedings of the National Academy of Sciences calls into question the unsustainable global food export system based upon unsustainable export volumes of virtual water.
‘Virtual Water’ – A New Way to Look at Climate Impacts - While international trade results in carbon emissions thanks to the fossil fuels burned by planes, trucks and ships, a Princeton University research team has found that world trade could also mean more efficient water use as a side benefit. And since water is a key resource in the production of climate-friendly energy sources, including hydroelectric and nuclear power, that could at least partially offset trade’s negative impact.