When the planners of Las Vegas peered into the future in 1950, they projected that the desert city's population--then 25,000--would be lucky to break 100,000 by the end of the century. As it turned out, they were off by a factor of 19, and as you leave the sizzling Strip--the iconic center of this metropolis of 1.9 million people--for the Lake Mead reservoir, 65 miles to the northwest, you can see the source of all that growth. In a city that receives just 4 in. of rain a year, residents in the sprawling housing developments where much of the Las Vegas population lives use an average of 165 gal. of water a day--and 90% of that comes from Lake Mead, the reservoir created by Hoover Dam in 1935. Lake Mead holds Nevada's 130 billion gal. share of the Colorado River's flow, split with six other states in the West--and for decades, says Pat Mulroy, head of the Southern Nevada Water Authority, "we'd assumed it was virtually drought-proof."
It's not. Through air that shimmers in the blast furnace of a July day, you can see how far Mead's water level has fallen. White bathtub rings of mineral deposits, measuring high-water marks that grow less high every year, circle the edges of the reservoir. Today Mead's water level is 1,108 ft., down from more than 1,200 ft. in 2000. (The official drought level is 1,125 ft.) If the water continues to decline, says marine geophysicist Tim Barnett of the Scripps Institution of Oceanography, "buckle up." Barnett co-authored a study estimating a 50% chance that a combination of climate change and increased demand could render Mead effectively dry by 2021. Mulroy doubts Barnett's dire conclusion, but she knows Las Vegas--and the world beyond--faces an existential crisis over water. "This is about being able to survive as a human being," she says.
The reason for the world's growing water woes is evident in the numbers. The planet fairly sloshes with water--326 quintillion gal. of it--but only 0.014% of that is available for human use. The rest is nonpotable ocean water or inaccessible freshwater, most of it frozen in polar caps. And the available water we do have is far from evenly distributed. About 1.1 billion people have no access to clean water, and half the planet lacks the same quality of water that the ancient Romans enjoyed. And while the amount of water on the planet remains fixed, the number of people drawing on it does not. The world's population could grow from 6.7 billion to more than 9 billion by 2050, according to U.N. projections. Much of that growth will be in countries that are already water poor. Not only will those extra billions need to drink, they will also need to eat--and agriculture sucks up two-thirds of the world's water. They will need electricity too, and in the U.S., nearly half the water withdrawn on a daily basis is used for energy production--to turn the steam turbines in coal plants, for instance.
What's more, none of that includes a new X factor: global warming. Some areas of the world will grow wetter as a result of climate change, but others will grow dryer, and so far the drying is winning. The area of the earth's land surface classified as very dry has doubled since the 1970s; by 2050, the Intergovernmental Panel on Climate Change believes, that trend will worsen. "You do the math, and it gets a little scary," says Stuart Minchin, a water expert with the Australian Commonwealth Scientific and Research Organization.
If the amount of water on the planet can't be changed, the way we use it has to. Water is wasted in rich countries and poor ones, in irrigation and industry, in bottles and pipes. "We're waking up," says Peter Gleick, head of the Pacific Institute, an environmental group based in Oakland, Calif. "But not fast enough."
In Australia, the wake-up call can no longer be ignored. Since 2002, the world's dryest inhabited continent has been in the grip of the worst drought in its recorded history. In Melbourne, you're no longer allowed to fill your swimming pool, and in bone-dry Brisbane, residents aren't allowed any external water use without a permit. But the real pain has been borne in the Murray-Darling River Basin in southern Australia, the heart of the country's $30 billion agricultural economy. Even in good times, Murray-Darling receives as little as 10 in. of rain a year, but 70% of the country's irrigation resources flow to the basin, creating a fertile desert able to produce 1.2 million metric tons of water-thirsty rice, among other crops
The good times, however, are gone. Last year the government allocated zero irrigation to the basin's farmers, and they produced just 18,000 metric tons of rice, the lowest yield since 1927. "No one around here has ever seen conditions like this," says rice grower Les Gordon, standing on the cracked ground of his 4,000-acre farm near the town of Barham.
The crisis is more than just Australia's problem. The collapse of the country's harvest contributed to a doubling of the price of rice this past spring, which in turn led to food riots in countries like Indonesia, the Philippines and Egypt. And that's the real impact of water scarcity--food scarcity. It takes 150 gal. of water to grow a pound of wheat, up to 650 gal. for a pound of rice and 3,000 gal. to raise the equivalent of a quarter-pound of beef.
With even the most aggressive plans to reverse global warming likely to take years to produce effects and population growth not likely to slow appreciably soon, the only answer is vastly improved water efficiency. That's where dry Australia is leading the way. In northern Victoria state, the government has launched a five-year, $1.3 billion project that will overhaul the region's century-old irrigation system, using computer-controlled channels that should significantly cut down on water waste, which today can reach 30%. "It's extracting the most benefit we can from the water we have," says Murray Smith, who heads the Northern Victoria Infrastructure Renewal Project.
Still, for all Australia's water worries, citizens there don't yet need to fear that when they turn on the tap nothing will come out. That's not the case in India, even in the capital of New Delhi, which supplies about 200 million gal. a day less than its population requires. Water is a worry, not just for poor Indians but also for middle-class ones, like R.K. Sachdev, a retired civil servant who lives with his wife in an upscale development in the city's southwest. "Every morning when I get up, my main worry is water," his wife Kusum says. Near the entrance to their flat, they keep a 265-gal. storage tank--locked to prevent theft. The couple are awake by 6:30 a.m. to ensure that the municipal supply is running, and they use an ultraviolet filter to purify water intended for drinking or cooking because contamination is constant.
In New Delhi's bursting slums, residents are often left to fight for buckets of water delivered via trucks, a process that is time consuming and expensive. The Sachdevs pay less than 2¢ per 26 gal. of water; the poor might pay that for a single quart from a private truck or even more for bottled water. "The rich end up paying just a fraction of the price to water their lawn than the poor do just to stay alive," says William Fellows, the regional water, sanitation and health adviser for UNICEF/South Asia. Worse, waste of the little water that is available is rampant. New Delhi loses as much as 50% of its water through leakage and other forms of inefficiency. It is a pattern repeated throughout the ill-planned urban areas of the developing world. "These cities are leaking buckets," says Junaid Ahmad of the World Bank.
The probable increase in yearly monsoons related to global warming should provide at least some new water, though out-of-control flooding will pose its own dangers. But the only other alternative comes from underground--and here India may be digging its own grave. There are now 23 million wells across India, up from 2 million 30 years ago, and those wells are draining the country's deep groundwater, or aquifer. Wells that once hit water at 20 ft. now need to go 80 ft. or deeper. New Delhi groundwater levels have declined 15% to 20% over the past several years. With almost no connection between the amount of water used and its cost, there is little incentive for rural farmers to stop drilling wells or for urban residents to conserve. "The price of water is a very important mechanism," says Ahmad.
In parched Las Vegas, Mulroy knows price is one of the best tools at her disposal to control the city's growing thirst. In the spring, officials approved a staggered rate hike that increased prices for low-volume users 17% and for the highest-volume users more than 30%. The city has also unleashed its water cops--officials like Dennis Walker who ride around sprawling new housing developments looking for violations of outdoor-water-use laws. Sprinklers are illegal during the daylight hours, and homeowners have to use a misting system rather than simply hose down the grass. Through ignorance or obtuseness, however, not everyone has gotten the message. At one house, Walker catches a sprinkler spraying a rock garden, the water leaking onto the boiling hot asphalt street. "That's pretty egregious," he notes laconically. He films the incident, with the time and date, and checks the address online to see if there are any prior violations. Fines can exceed $1,000 for multiple infractions.
All these policies are having an effect. From being one of the most wasteful cities in the U.S.--in the 1980s, Las Vegas used almost twice as much water per capita as did far wetter New York--Vegas may now get more economic bang for its water than any other place on earth. Though the city has grown by 300,000 people since 2002, it uses less water today than it did six years ago, and leakage is below 5%. "Failure is not an option," says Mulroy.
The same is true for the rest of us. In the past century, we treated water as if it were inexhaustible. But that illusion has dried up. The only way to thrive in a warmer, thirstier world will be to learn to get more out of less. "We have the time to change," says Scripps' marine geophysicist Barnett. "Do we have the will to change? I don't know."