How Much Longer Until We Run Out of Enough Drinkable Water?

For at least three decades, Americans have had some inkling that we face an uncertain energy future, but we’ve ignored a much more worrisome crisis—water. Cheap and seemingly abundant, water is so common that it’s hard to believe we could ever run out. Ever since the Apollo astronauts photographed Earth from space, we’ve had the image of our home as a strikingly blue planet, a place of great water wealth. But of all the water on Earth, only about 2.5 percent is freshwater—and two-thirds of that is locked up in glaciers and ice caps. Less than one hundredth of one percent of Earth’s water is fresh and renewed each year by the solar-powered hydrologic cycle.

Across the United States and around the world, we’re already reaching or overshooting the limits of that cycle. The Colorado and Rio Grande Rivers are now so overtapped that they discharge little or no water to the sea for months at a time. [1] In the West, we’re growing food and supplying water to our communities by overpumping groundwater. This creates a bubble in the food economy far more serious than the recent housing, credit, or dot-com bubbles: We are meeting some of today’s food needs with tomorrow’s water. [2]

The massive Ogallala Aquifer, which spans parts of eight states from southern South Dakota to northwest Texas, and provides 30 percent of the groundwater used for irrigation in the country, is steadily being depleted. [3] As of 2005, a volume equivalent to two-thirds of the water in Lake Erie had been pumped out of this water reserve. Most farmers will stop irrigating when the wells run dry or the water drops so far down that it’s too expensive to pump.

At the same time, climate change is rewriting the rules about how much water we’ll have available and when. Climate scientists warn of more extreme droughts and floods, and of changing precipitation patterns that will make weather, storms, and natural disasters more severe and less predictable. [4] The historical data and statistical tools used to plan billions of dollars worth of annual global investments in dams, flood control structures, diversion projects, and other big pieces of water infrastructure are no longer reliable. [5]

While farmers in the Midwest were recovering from the spring flood of 2008 (in some areas the second “100-year flood” in 15 years), farmers in California and Texas fallowed cropland and sent cattle prematurely to slaughter to cope with the drought of 2009. In the Southeast, after 20 months of dryness, Georgia Governor Sonny Perdue stood outside the State Capitol in November 2007 and led a prayer for rain, beseeching the heavens to turn a spigot on for his parched state. Two years later, Perdue was pleading instead for federal aid after intense rain storms near Atlanta caused massive flooding that claimed eight lives. [6]

Although none of these disasters can be pinned directly on global warming, they are the kinds of events climate scientists warn will occur more often as the planet heats up. It’s through water that we’ll feel the strains of climate change—when we can no longer count on familiar patterns of rain, snow, and river flow to irrigate our farms, power our dams, and fill our city reservoirs.

In answer to the climate crisis, the economy will need to move away from fossil fuels toward solar, wind, and other non-carbon energy sources. But there is no transitioning away from water. Water has no substitutes. And unlike oil and coal, water is much more than a commodity: It is the basis of life. A human being can only live for five to seven days without water. Deprive any plant or animal of water, and it dies. Our decisions about water—how to use, allocate, and manage it—are deeply ethical ones; they determine the survival of most of the planet’s species, including our own.