Water Tight, cont.
Blue Jean Surprise
Knowing the water footprint of goods and services can help businesses use water more efficiently (and work with suppliers to do the same), proactively protect water supplies and reduce vulnerability to changing water quality and quantity.
“There’s no doubt that this is a very important component of what companies are going to need in order to begin to evaluate their water-related risks and impacts,” says Jason Morrison, program director with the Pacific Institute, a California-based sustainability think tank. “You can’t ultimately manage what you don’t measure.”
Take that pair of blue jeans: According to the Water Footprint Network, producing one pound of cotton uses close to 1,500 gallons of water on average: 45 percent in irrigation water from surface or ground supplies (known as “blue water”), 41 percent in rainwater stored in the soil (green water), and 14 percent used to dilute agricultural runoff, as well as chemical-laden wastewater from textile mills (grey water).
In 2007, clothing manufacturer Levi Strauss & Co. assessed the water footprint of a pair of jeans from production to disposal and found that each pair used about 925 gallons of water from cradle to grave. About 1 percent was used directly in the manufacturing process; more than 50 percent in the supply chain, including growing the cotton and selling the pants; and about 45 percent by the consumer to care for the jeans.
Levi Strauss is setting targets for reducing water use at U.S. facilities, including cutting water use in half at a particularly water-hungry Nevada distribution center by 2012. Focusing its water stewardship efforts on its supply chain, the company has established “global effluent requirements” covering water use, quality and reclamation for its factories and bulk fabric suppliers, and collects data on water use from its suppliers.
23 Gallons to the Pint
Beer production’s water consumption is also linked to its supply chain. Around 89 percent of the water needed to create a pint of brew is consumed in raising crops such as barley and hops. SABMiller, a global brewing company that owns nearly 200 brands (including Coors, Grolsch, Miller and Pilsner-Urquel), recently partnered with international conservation group WWF to produce the report Water Futures, an assessment of the company’s exposure to water risks in South Africa, Tanzania, Ukraine and Peru.
SABMiller found its Tanzania operations averaged nearly 23 gallons of water used for every pint of beer produced. South Africa’s pint of beer took 19 gallons of water to produce, while Peru and Ukraine used just 7.5 gallons of water to create a pint of brew.
In each country, 90 percent or more of the water footprint came from cultivating crops. But for countries with such divergent economies and environments, these amounts and percentages don’t tell the full story.
Peru and Ukraine use substantial amounts of grey water in agriculture, for instance, while the footprints of South Africa and Tanzania are primarily green and blue water. In Ukraine, deteriorating infrastructure is a major risk to water supplies, while in Tanzania and Peru, population growth will present a challenge. South Africa’s brisk economic expansion means that different industries are increasingly vying for the same, relatively constrained water supply. All four countries face water pollution challenges, but in Ukraine a major factor is deteriorating infrastructure, while in Peru and Tanzania, it’s population growth.
The 630 gallons of water it takes to produce one hamburger is no small matter, either. Much of it is concentrated in growing grains as feed for cattle. “Holistic ranching” offers some solutions. Mimicking the natural behavior of bison, munching cattle are moved across open grasslands, letting some areas recover as others are grazed.
Free-range ranching can help restore grasslands and improve water conditions: The animals spread grass seed as they move, and grind it into the soil with their hooves. As the grasses and other vegetation grow, the roots help lock down water from rainfall so it ends up in the soil and groundwater rather than lost to runoff or evaporation. The catch: most grass-fed beef cows are sent to feedlots before slaughter to fatten up on water intensive grains. Further, federal subsidies keep the costs for corn feed low compared to free-range feeding.
Where's All the Water?
To understand how water can become scarce, consider that the human population numbered under 2 billion in 1900, surpassed 6 billion by 2000, and is surging toward 9 billion by 2050. And we’re not the only living organisms on this planet that need freshwater to survive.
The global water supply, by comparison, is finite. Whether it’s in the form of ice, vapor, steam or liquid, the amount of water on Earth today is about the same as the water that slaked the planet’s thirst a million years ago. Only a very thin slice of that supply is the liquid freshwater that we depend upon for drinking, washing, irrigation, manufacturing, energy and more.
The world’s total water supply is estimated at about 333 million cubic miles, or about 366 trillion gallons. Of this, 97 percent, about 353 trillion gallons, is salt water.
Of the remaining 13 trillion gallons, all freshwater, 68.7 percent is locked up in glaciers and ice caps, 30.1 percent is stored in rock formations and soil as groundwater, and 0.9 percent exists as vapor and in living things.
Just 0.3 percent — one third of 1 percent — of this freshwater supply exists on the surface of the Earth as lakes (87 percent), wetlands (11 percent) and rivers (2 percent). —Emily Gertz
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Last modified on January 23, 2012