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Rising Impacts of Water Use
“A sustainable and secure society is one that meets its water needs without destroying the ecosystems upon which it depends or the prospects of generations yet to come.”
Fresh water is a life support. Yet over the past half-century the scale and pace of human influences on freshwater systems has accelerated rapidly, along with population and consumption growth. Worldwide water demands roughly tripled. Agriculture now accounts for about 70 percent of world water use, industry for about 22 percent, and towns and municipalities for 8 percent.
The impacts of rising water consumption are increasingly visible. Water tables are falling in many countries from the overpumping of groundwater. Major rivers like the Amu Dar’ya, Colorado, Ganges, Indus, Rio Grande, and Yellow now run dry for portions of the year. Worldwide, freshwater wetlands have diminished in area by about half. Today, at least 20 percent of Earth’s 10,000 freshwater fish species are at risk of extinction or are already extinct.
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A Dam-Building Frenzy The number of large dams climbed from 5,000 in 1950 to more than 45,000 today—an average construction rate of two large dams a day for 50 years. For a time, only the benefits of these engineering projects were registered—not their social and ecological costs, in terms of people displaced from their homes, fisheries destroyed, soils contaminated by salts, and aquatic species imperiled. |
Water-Rich, Water-Poor
“Because of the influence of power, politics, and money, natural scarcity of water does not imply deprivation; nor does natural abundance imply access… Easing both overconsumption and under-consumption are flip sides of the global water challenge.”
Just six countries—Brazil, Russia, Canada, Indonesia, China, and Colombia—account for half of Earth’s total renewable freshwater supply. Canada ranks near the top of water wealth, with more than 92,000 cubic meters of water per inhabitant. At the water-poor end of the spectrum are Jordan with annual renewable supplies of 138 cubic meters per person, Israel with 124, and Kuwait with essentially none.
Water is often distributed unevenly within countries as well. China, for instance, has 21 percent of the world’s people, but only 7 percent of Earth’s renewable fresh water—and most of that supply is in the southern portion of the country.
The most urgent task is to provide all people with at least the minimum amount of clean water and sanitation needed for good health. Today, one out of five people in the developing world—1.1 billion in all—face daily risks of disease and death because they lack “reasonable access” to safe drinking water.
Yet the large gap in coverage worldwide has almost nothing to do with water scarcity. Globally, providing universal access to 50 liters per person per day by 2015 would require less than 1 percent of current global water withdrawals. There is more than enough water, but so far the political will and financial commitments to provide the poor with access to it have not been sufficient.
Consider Ethiopia. An overflight of the country reveals a land thirsting for water, where in 2003 more than 12 million people faced famine; yet 84 percent of the flow of the Nile River originates within Ethiopia’s territory. Meanwhile, in the United States, one resident of water-strapped Orange County, Florida, was billed for 15.9 million liters of water for one year—a volume roughly equivalent to what 900 Kenyans use annually.
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The United States: A Water Glutton
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Water, Crops, and Diets
“Raising the productivity of agricultural water use is critical to meeting people’s food needs as water stress deepens and spreads.”
Agriculture uses about 70 percent of all the water extracted from Earth’s rivers, lakes, and underground aquifers, and as much as 90 percent in many developing countries. Recent projections indicate that by 2025 numerous river basins and countries will face a situation in which 30 percent or more of their irrigation demands cannot reliably be met because of water shortages.
To raise the productivity of water, it will be necessary to deliver and apply water to crops more efficiently and to increase crop yields per liter of water consumed. This can be done by using drip-sprinklers and other micro-irrigation systems, changing cropping patterns and growing methods to get more crop per drop, and adopting high-yielding and early-maturing crop varieties. Shifting diets, too, will enable people to satisfy nutritional needs with less water. It takes five times more water to supply 10 grams of protein from beef than from rice, and nearly 20 times more water to supply 500 calories from beef.
Cities and Homes
“With nearly half of the global population now living in urban areas, a figure that will increase to 60 percent by 2030, meeting the growing water desires of the rich and the water needs of the poor is now a significant challenge.”
Cities claim less than 10 percent of the world’s freshwater withdrawals. Yet their concentrated consumption requires complex, capital-intensive infrastructure that draws deeply from finite surface and subsurface water supplies. The majority of the world’s 16 mega-cities—those with 10 million or more inhabitants—lie within regions experiencing mild to severe water stress. As urban water demands increase, the pressure on agricultural and rural areas to sell or surrender their water rights will intensify.
Recovery of water “lost” due to leakage, faulty measurement, or corrupt accounting constitutes a great untapped water supply that could help cities and regions facing water scarcity meet their true water needs. In many cities, losses represent an astonishing 40 percent or more of total water supply. Often the poorest countries, whose people lack adequate supplies, have the highest rates of water waste, although the privatized water industry’s record in industrial countries is hardly stellar.
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Tackling Urban Water Waste
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Industrial Water Use and Material Goods Consumption
“Industrial demands in developing and emerging economies are growing rapidly and will compete for scarce water supplies with both cities and farms.”
Industries account for about 22 percent of the world’s total freshwater withdrawals, but they claim a far higher share in industrial countries (59 percent on average) than they do in developing ones (10 percent). In addition to using rising quantities of water, industries generate large volumes of wastewater; in developing countries, much of this is currently released untreated into nearby rivers and streams, polluting scarce supplies.
An impressive number of industrial and commercial users have cut their water demands anywhere from 10 to 90 percent while boosting productivity and profits. Unilever, a multinational producer of food, home, and personal care products, used an average of 4.3 cubic meters of water per ton of production in 2002, a one-third drop from the 6.5 cubic meters per ton used in 1998. While cost savings is often the primary motivation for efficiency investments, other incentives include the need to comply with permit requirements, advances in onsite treatment technologies that allow process water to be recycled and reused, and the availability of low-cost reclaimed nonpotable water.
A New Mindset for Managing Water
“There is no mystery about why so much of the water extracted for human use is wasted and mismanaged: the policies that drive water decisions in most cases foster inefficiency and misallocation rather than conservation and sustainable use.”
Achieving an optimal balance between meeting human needs and protecting valuable ecosystem functions requires allocating sufficient water throughout the year to sustain those functions. Setting limits on the use of rivers and other freshwater ecosystems is the key to sustainable economic progress because it protects the ecosystems underpinning the economy while spurring improvements in water productivity.
In Australia, water extractions from the Murray-Darling river basin—the nation’s largest and most economically important—have been capped in an effort to arrest the severe deterioration of that river’s ecological health; in 2003, the Murray’s flow dropped so low that its mouth became clogged with sand. In South Africa, an innovative 1998 water law calls for meeting the basic water requirements of both people and ecosystems before water is allocated to non-essential uses.
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Policy Priorities
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Our Personal Choices
“In light of population growth and rising affluence, individuals have an important role to play by making responsible choices about their consumption patterns—from diets to material purchases.”
Just as individual choices about diets and landscapes can make a big difference on the total human impact on water bodies, so can choices about the consumption of material goods. Virtually everything people buy—from clothes to computers to cars—takes water to make, and the manufacturing process may result in pollution of streams and lakes as well.
By choosing a healthy and less water-intensive diet, an attractive and climate-appropriate landscape, and a lifestyle with fewer material goods, individuals can lessen their impact on Earth’s freshwater systems without sacrificing personal satisfaction. Such choices can turn water consumers into water stewards.
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What You Can Do
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