Walk into any grocery store and you’ll find a barrage of labels on every product that proudly and loudly proclaims its ecofriendly pedigree: Organic! Fair trade and shade-grown! Local! An article last week in the Wall Street Journal posits two of the latest entries into the fray: virtual water and water footprint.
Relatively new additions to the enviro-lexicon, “virtual water” is the volume of water required for producing a commodity, and “water footprint” measures “the total volume of freshwater that is used to produce the goods and services consumed by the individual or community.” The water is “virtual” because it is often not part of the final product. For a cotton t-shirt, for example, the virtual water accounts for the water needed to grow and irrigate the cotton and the water used during the manufacturing process. The average water footprint of a country depends on four factors: climate, agricultural practice, total volume of product consumption, and consumption patterns. By standardizing certain variables, this calculation can assist countries in identifying areas where water-use efficiency and conservation can be improved.
For example, “it takes roughly 20 gallons of water to make a pint of beer, as much as 132 gallons of water to make a 2-liter bottle of soda, and about 500 gallons, including water used to grow, dye and process the cotton, to make a pair of Levi's stonewashed jeans.” Interestingly, while the United States tends to use less virtual water in producing commodities, the nation has a high average water footprint – more than 655,000 gallons per person per year or approximately 1,800 gallons per person per day – largely as a result of a diet high in meat intake and high consumption of industrial products.
With growing population, increased development, and mounting ecosystem pressures on water resources around the world, the concept of virtual water is useful in determining the actual water scarcity of a country. Jordan withdraws an annual average of 1 billion cubic meters of water from domestic resources but imports 5 to 7 billion cubic meters of virtual water each year. In contrast, Egypt withdraws an annual average of 65 billion cubic meters from domestic resources and imports only 10 to 20 billion cubic meters. International trade in virtual water helps to relieve pressure on domestic resources by importing water-intensive products from countries that have plentiful water resources instead of relying on limited domestic sources for those products.
Despite the difficulties in accurately measuring virtual water and water footprints, the two concepts seem poised to follow the lead of carbon-footprint measurements in raising public awareness of the environmental impact of everyday activities. Websites already offer water footprint calculators. Beyond individuals’ curiosity, measuring water footprints may prove useful to large companies. The Wall Street Journal article noted that:
Unilever PLC, which owns 400 food and household brands, estimates that it saved about $26 million by reducing water waste in its factories from 2001 to 2007. Recently, the company has started reducing water used to grow ingredients for its Lipton Tea and Ragu tomato sauce by using drip irrigation to grow black tea in Tanzania and tomatoes in California. Such efforts stand to have a significant impact: Unilever buys 7 per cent of the world's tomatoes, and 12 per cent of the world's commercial black tea.
If measuring water footprints and virtual water, which until now have only silently accompanied products into the stream of commerce, contributes to water conservation by bringing more attention and awareness to water consumption, it is a welcomed attention that will surely increase as the strains on water resources grow.