Facing the Freshwater Crisis
As demand for freshwater soars, planetary supplies are becoming unpredictable. Existing technologies could avert a global water crisis, but they must be implemented soon
Facing the Freshwater Crisis
- 6. Exploit Advanced Desalination Technology Ninety-seven percent of the world's water is salty. New lower-cost desalination plants could expand freshwater supplies for coastal population centers. Essentially, pressure is applied to salty water (left) so that water molecules within it pass through a selective membrane, yielding freshwater on the other side (right). Although the filter process tends to be power-hungry, next-generation membranes, energy-recovery techniques and other innovations could help save energy. 5W INFOGRAPHICS
- 5. Adopt Low-Water Sanitation Urban and suburban sanitation services soak up plenty of water, some 100 cubic kilometers worldwide. Low-water-use toilets could make a big dent. Residents of the Gebers Housing Project in suburban Stockholm are demonstrating a system that operates like a garden composter. The system first separates excrement from urine, which is used as liquid farm fertilizer, and the remainder is recycled into fertilizer by microorganisms in a compost bin. Such technology can be safe, even in fairly dense cities and suburbs. 5W INFOGRAPHICS
- 4. Ship "Virtual Water" Virtual water is the amount of water that is used to produce food or another product and is thus essentially embedded in the item. A kilogram of wheat, for instance, takes about 1,000 liters of water to make, so each kilogram "contains" that quantity. Export-trade shipments of wheat to an arid country means that the inhabitants will not have to expend water on wheat, which eases pressure on local supplies. 5W INFOGRAPHICS
- 3. Water Investment Needs, by Area Maintenance of the water infrastructure is crucial to prevent deterioration, leaks and outright breaches. At the same time, growing populations and those becoming more affluent need new, efficient water-delivery systems. To help conserve freshwater supplies, developed nations and some less developed ones will have to spend trillions of dollars on maintaining and creating efficient infrastructures during the next quarter of a century. 5W INFOGRAPHICS
- 2. Charge More for Water Freshwater in the U.S. and other economic powers has traditionally been priced so low that users have had little incentive to save it. Few people take the time to conserve a commodity that seems almost free--no matter how valuable. Higher prices would promote conservation as well as investment in less wasteful water infrastructures. 5W INFOGRAPHICS
- 1. Conserve Irrigation Water Farm irrigation eats up huge quantities of water; a 10 percent drop in irrigation water would save more than is used by all other consumers. Plugging leaks in the irrigation water-delivery system, banking water underground to limit evaporation, applying drip-irrigation methods and modifying crops to withstand less moisture could do the trick. Below, water from the Colorado River flows in an open irrigation canal in California's famed Imperial Valley croplands. BOB ROWAN Progressive Image/Corbis
