Water is a life force. Without it Earth would be a barren desert—Mars, basically. Oceans cover 70 percent of our planet’s surface, just as we humans are more than half water. And, paradoxically, we need freshwater to survive but if the polar ice caps melt, the ensuing floods will kill us. No wonder so many postapocalyptic scenarios revolve around water, or the lack of it.
When Earth first formed, it was a dry, bleak landscape of volcanoes and gas-leaking fissures. A molten outer layer dissipated any chance of water—or life. But as the outer crust cooled, icy comets barraged the planet and melted into oceans. And so the basic framework for sustainable life began with a cosmological snowball fight.
Ice has not always been life’s benefactor. At least five ice ages have come and gone, inundating entire continents—even freezing over the Baltic Sea—and the last few put a frosty check on human advancement. Today only small ice shelves remain on the poles of the planet, cooling the ocean. Though these glaciers account for about 10 percent of Earth’s surface area, in the grand picture they are no more than ice cubes, constituting only two percent of the ocean’s weight. And they’re shrinking. Global warming is melting the glaciers, gushing tons of new water into the sea and raising the water levels. In time the elevated seas will wash away the coasts and submerse some of the world’s smaller islands. So fill the cocktail shakers with spirits on the rocks and get to the beaches while they last.
In February 2012, Russian scientists resurrected a 30,000-year-old narrow-leafed campion plant (Silene stenophylla). The team discovered the fruit tissue preserved in the permafrost (perennially frozen soil) of Siberia, then cultured it to create a thriving, flowering specimen with a more successful germination rate than its modern counterpart. Researchers have gone giddy with speculation about what else may remain under the ice. Could animals be regenerated with the right science? Could a woolly mammoth canter its bulk across the tundra once more?
Permafrost exists on Mars, too. Although no living being appears to inhabit the planet, Mars might once have looked very similar to Earth. The Martian surface is etched with dried-up riverbeds and basins, perhaps indicating that water once flowed over its surface. If so, life could have flourished. One theory even suggests an asteroid smashed into the red planet, picking up life forms (the equivalent of space-faring hitchhikers), and then landed on Earth—meaning earthlings could have descended from Martians. What might be preserved in Martian ice? Could a manned mission to Mars pave the way for an interplanetary family reunion?
Water could very well contribute to a real-life postapocalyptic scenario. Think about the greenhouse effect, which traps solar energy within the atmosphere and cooks planets beyond recognition. This has already happened to Venus, dry but sweltering beneath a blanket of clouds. Earth, on the other hand, contains 1.5 quintillion tons of liquid. If all this were to heat and evaporate, the weight of the saturated air could crush every living organism. The title character in the cult-classic Mad Max movies, wandering the barren outback, looking for something to fuel his car and for something—anything—to drink, is warning us.
All hope, however, is not lost. The Australian highwayman could always take to space. Scientists have spotted a floating reservoir (only 12 billion light-years away) containing 140 trillion times more water than there is on Earth. On the downside, this water vapor floats around a black hole. Maybe Max should settle closer to home: Mars contains sizable quantities of ice, and its surface of dusty desert plateaus doesn’t look that much different from parts of Australia. On the way, Max could stop at the moon to process rocket fuel with excess hydrogen—and collect vital water from its vast caverns.
As the world’s population has increased, the purity of freshwater in poorer, dryer areas has suffered. Cesspools are breeding grounds for malarial mosquitoes, particularly in underdeveloped regions with insufficient water treatment. Cholera (Vibrio cholerae) is just one of myriad nasty bacteria that lurk in stagnant water. And diarrhea from tainted water is the second most common cause of child mortality worldwide. These horrors surface only when water is present. What happens when there is none?
Some predict that by 2030 nearly half the human population will face water scarcity. This explains why so many postapocalyptic movies explore a dehydrated future. In Mad Max: Beyond Thunderdome (1985), Mel Gibson stumbles across an anhydrous landscape. When he finally reaches a desolate town, a peddler tries to sell him “pure water.” The road warrior tests the liquid and finds it radiated. Dubbed “Mad Max on water,” 1995’s Waterworld offers an alternative take: a world where oceans cover all the land, yet it is nearly impossible to find anything safe to drink. The film opens with Kevin Costner filtering his own urine. There seems to be a thin and dangerous line between potable water and potty water.
During the dog days of summer, all anyone wants to do is cool off. To soothe our skin, we find a creek to swim in or a sprinkler to run through. To chill from the inside out, we harvest and blend ice for margaritas. But some parts of the world are “too darn hot,” as Cole Porter put it, all year long. The solution: the water our own bodies produce.
When the sun bears down like an angry god and the very streets begin to shimmer, salty water perspires from the pores then evaporates off the skin, expelling latent heat from the body: the world’s first air conditioner. While the sweat’s salt remains in embarrassing stains, the vapor collects in a cloud and, in due course, cascades to the ground as fresh rain. So the human body creates its own water cycle—and supply. Of course, if we tried to live off our own recycled water, there might not be enough to go around. Thankfully, the oceans sweat as well, heaving boatloads of water into the sky, to return in cooling drafts and wash away the salt left behind on our skin.
Should we sail the seven seas? People have been drawn to the vast watery expanse since before Noah built his ark. Ishmael from Herman Melville’s Moby-Dick asks, “Why is almost every robust healthy boy…crazy to go to sea?” The ocean, with all its sunlit glitter and frothy crests, seems to invite great adventure, somewhere just beyond the horizon.
Yet the human body is not terribly compatible with the ocean. Forget about man-eating sharks or hundred-foot-tall rogue waves—or icebergs, or riptides, or simply drowning. The human body needs freshwater, and the majority of water on Earth doesn’t fit the bill: 96.5 percent is highly saline. Drinking seawater dehydrates the body. Any more than a few sips, and the kidneys shut down in an effort to jettison excess salt. Without hydration, hallucinatory madness sooner or later descends upon the brain.