The concept of virtual water helps us understand how much water is needed to produce different goods and services. In semi-arid and arid areas, knowing the virtual water content of a product or service can be useful in determining how best to use the scarce water available.
When crops and products are produced, many of them use a great deal of fresh water in their production processes. That water is not retained in the final product but the volumes used to produce it are waste water that is not available for other uses in the area where the product is made. In principle, therefore, the producing area is exporting virtual water and depleting its own usable water sources. The numbers are astonishing:
65 gallons for a pound of potatoes
Between 250 and 650 gallons for a pound of rice
3000 gallons for the feed for a cow to produce ¼ pound of hamburger
650 gallons for a pound of cheese
Between 500 and 1000 gallons for a cow to produce 1 quart of milk
400 gallons to produce 1 pound of sugar
2560 gallons to produce 1 pound of coffee
1320 gallons to produce a small steak
A glass of brandy requires 650 gallons
When crops such as cotton and alf alpha are added, the consumption numbers become astronomical. The Russian Government, in its attempt to cash in on the exponential growth of the cotton industry have diverted the rivers that used to feed the Aral Sea, the fourth largest inland body of water in the world. That sea has virtually disappeared. The fish that sustained the local population, the aquifers from which they got their drinking water and most of the people themselves have also disappeared, all to produce more cotton. There are stretches of California, Arizona and Nevada that are headed in the same direction.
As an aside, the idea that some people in the United States are running out of drinking water because others are trying to create a Garden of Eden in their desert backyard in Palm Springs is, frankly, criminal.
In the U.S. wheat production is enormous and so is the water usage of that production. The surplus grain is shipped worldwide and even stored in enormous silos. That badly depletes the available drinking water that is badly needed elsewhere in the country.
Water and water usage is already causing small “wars” in the western United States and on the Mexican border where the Rio Grande river now stops over a hundred miles from the sea. However, it is not just a U.S. problem. Even the mighty Ganges in India doesn’t reach the sea for many months of the year for the same reason. The water is diverted for crop production.
Many would predict that the next World War will be fought over water rights!