Before dismissing some child’s fantasy, think again, because mine was mainly true. Sentient or not, water rules this planet. Every living thing and process on Earth needs it, and fails without it.
Which raises a problem, because there’s only so much of it, and we can’t make any more. Even though we keep acting as if we can.
Some geologists believe our water formed with Earth itself, while others say colliding asteroids brought it. Evidence suggests that both groups may be correct. Conceivably, another meteoric strike might bring more water—but such collisions also bring collateral damage. Ask the dinosaurs.
So we’re stuck with what we have. If all of Earth’s water were compressed into a sphere, its total volume would be about 1/800th of the entire planet’s. That sounds like a lot, until you realize that 96.5 percent of it is too salty for human consumption due to those dissolved rocks.
Two thirds of the remainder, freshwater, is locked up in polar ice, glaciers, and permanent snow—at least for now. Unfortunately, when it melts, most of it will also end up as seawater. Some don’t think that’s a problem: We can desalinate, they say, and with all these oceans, we’ll never run out. But like most techno-fixes, desalination solves one problem only to bring others. Removing salt is energy intensive, costing significant money and coughing up considerable CO2. Markets can absorb only a fraction of the mounds of sea salt that desalinization produces, and dumping it back into the ocean disrupts coastal ecology. At best, it provides expensive drinking water. It’s far too pricey for crops. And therein lies the real conundrum, because agriculture guzzles some 90 percent of the water we humans use.
All of our earnest measures to conserve water at home—low-flow showerheads, toilets, dishwashers, and washing machines; fewer trips to the car wash—are laudable: We should do everything we can. That includes pretending we’re astronauts—which we are, on Spaceship Earth—and drinking recycled wastewater. (Don’t gag: Houston already drinks mostly Dallas–Fort Worth’s effluent, which now constitutes nearly the entire flow of its main source, the Trinity River.)
Probably the biggest saving urban dwellers can make is mulching shrubbery and forgoing lawns for drought-resistant native grasses and plants. But although home landscaping may quaff more than half a household’s water, collectively it’s a pittance—around 4 percent of our total usage—compared with all those almonds that slurp a gallon apiece, or about 14 gallons per lettuce head, 122 gallons per pound of corn, 450 gallons per quarter-pound hamburger, and so on.
If agriculture is overwhelmingly the culprit, what do we do—eat less? We must do something, because the future holds even less water. Changing climate now undercuts snowpacks that annually replenish the great water sources of the Rockies, Sierra Madre, Andes, and Himalayas. Droughts like California’s, affecting half of U.S. food production, are occurring worldwide. Rising seas are fouling wells in our most fertile lands, river deltas: The Arabian Sea creeps up Pakistan’s Indus River a kilometer each year. And we’ve polluted—wasted—an incalculable amount.
But mostly, water is running thin because there are now so many of us.
Far more even than medical advances that lowered child mortality and extended adult life spans, modern agriculture is why human numbers suddenly quadrupled in the past century—the most abnormal population spurt in biological history. It began with artificial nitrogen fertilizer, which blew the lid off how much plant life can grow here: 40 percent of us simply wouldn’t exist without it. Next came Green Revolution corn, wheat, and rice hybrids that yielded much more grain per stalk. As these lab-bred crops didn’t evolve with natural defenses, they’re chemically hooked on not just fertilizer but also water-polluting pesticides and herbicides. But the resulting abundance meant that millions who would have died of famine lived to bear children, who grew up to beget even more.
Accordingly, the first Green Revolution recipient, India, will soon surpass China as the world’s most populous nation. Since grains—humanity’s most important foodstuff—collectively consume the most water worldwide, not coincidentally India’s water is in crisis. Wells in its breadbasket, Punjab, have dropped so low that over the past two decades, it’s the main reason that 270,000 indebted Indian farmers, unable to afford more drilling and bigger pumps, have committed suicide—often by drinking pesticide.
Half the world’s grain harvest is fed to livestock that is then fed to humans. Since producing a pound of beef requires roughly 10 times the water as growing a pound of wheat, and since it takes about 6 pounds of grain to make that pound of beef, our simplest way to save water is to eat less meat. But most humans are omnivorous, and worldwide meat demand is actually rising, especially in fast-developing, overpopulated Asia, so persuading people to eat grain directly instead won’t be simple. The most reason-able first step may be convincing them that consuming meat in moderation is healthier for both people and the planet.
Another measure might be digging basins to capture the floods that, from Pakistan to Texas, now alternate with drought. But balancing out unpredictable rainfall fluctuations also isn’t easy, and building huge reservoirs takes money and space. Some Californians think the best bet may be to reintroduce beavers, whose dams turn streams into the chains of natural catchment ponds they were before human trappers arrived.
With climate and water supplies already shaky, and with nearly half the unfrozen terrestrial Earth now devoted to feeding just one species—ours—we 7.3 billion Homo sapiens are literally pushing off the planet other species with which we have coevolved. We may realize too late that we’ve lost something we needed. Biodiversity collapse aside, with a million more people added every 4½ days, today’s Green Revolution scientists worry that in the next half-century we’ll need to grow more food than has been consumed in all of human history. So they’re trying to coax even more from each plant by genetically modifying the way they photosynthesize and by enhancing genes for drought tolerance. But developing commercial-scale GM crops takes at least 20 years—assuming we accept them, which many of us don’t.
Ultimately, the most cost-effective way to conserve not just water but everything is family planning. Doubling today’s global reproductive health budget to just $8 billion per year—less than what America spent per month last decade in Iraq and Afghanistan—could buy enough contraception for everyone. But the very best contraception is female education, because schoolgirls worldwide postpone pregnancy while studying—and then, to use that learning, average fewer than two children. The Vienna Institute of Demography calculates that universal access to contraceptives and education could reduce population to a far more sustainable 6 billion by 2100, rather than the unimaginable 11 billion toward which we’re currently headed.
All of those educated women would help solve the challenges facing us, and their fewer children would need less food—and less water and chemistry to grow it.
When an asteroid exterminated the dinosaurs 65 million years ago, it left a large, vacant niche, into which crept a minor character in the age of reptiles: mammals—and here we are. If we turn out to be the asteroid this time, crushed under the weight of our own overwhelming presence, in time Earth will rebound, as it has so brilliantly after every prior mass extinction. That resurrection will be lubricated by water, which will still circulate, evaporate, condense, and repeat.
There will actually be more of it available to nurture life than today, because eventually our pollutants will leach from the trillions of gallons we’ve sullied and squandered. Well-watered Earth will again be beautiful, albeit bereft of our remarkable selves.
Unless, that is, we wisely heed the abundant knowledge we’ve accrued and start to live within our world’s means. Then maybe we and our mystical children will get to stay around to see it.
Alan Weisman is the author of Countdown: Our Last, Best Hope for a Future on Earth? and The World Without Us. His works have been translated into nearly three dozen languages.