by Linda Marsa, investigative journalist, contributing editor at Discover magazine and author of Fevered: Why a Hotter Planet Will Hurt Our Health—And How We Can Save Ourselves.
Clean water is the lifeblood of modern society. None of the incredible scientific advances of the 20th century have affected human health as profoundly as the availability of clean water. Cholera, typhoid, and malaria have virtually vanished in industrialized nations because of advanced sewage systems and municipal drinking systems. And clean water has fed the world: Irrigation for agriculture accounts for at least two-thirds of all water use. Sure, we've had periodic dry spells and even long-term droughts, but societies have largely learned how to survive the bad years by diversifying crops, installing irrigation systems, or even buying crop insurance.
But a hotter planet might create conditions that are beyond the scope of our normal coping mechanisms. By the end of this century, studies show, nearly half the world's population—about 3.2 billion people—could suffer from severe water scarcity, which threatens the food supply. Here in the U.S., climate change will magnify the water challenges we face. We'll see more frequent and severe droughts and increasing damage from floods coupled with rising water demand from a population that is expected to grow by up to 150 million people by 2050.
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Have we reached "peak water?" This is a term coined by Peter Glieck, one of the world's leading water experts and director of the Pacific Institute, an environmental think tank in Oakland, California, to describe that crucial tipping point when nature's ability to replenish stores of fresh water are forever outstripped by voracious human demand fueled by explosive population growth. Experts say that mankind's unquenchable thirst means we're using water and polluting it faster than it can be renewed through the natural water cycle—hence the dire shortages, a situation that will only worsen as the climate changes, rainfall patterns shift, and the future becomes dryer.
Paradoxically, we're not truly running out of water. We actually have the same amount of water on Earth as we did aeons ago when amphibians first stuck their toes out of water and explored dry land—about 360 quintillion gallons of it. The hydrologic cycle still follows basic natural laws: Water evaporates from the oceans, lakes, and rivers, then forms clouds in the atmosphere, falls as rain, and seeps into the ground before it surfaces once again in springs that flow into rivers and lakes. "But there are now indications that the hydrologic cycle is accelerating, which is exactly what climate modelers said would happen from a warming planet," Peter Gleick told me when I interviewed him for my book, Fevered. "That means more evaporation, more precipitation, more runoff into the ocean, which translates to dry regions, like the Southwest, getting even dryer because of higher evaporation rates and wet areas getting inundated by floods because of faster melting of snowpacks. That's part of the new climate we're going to have to deal with."
Read an Excerpt of Marsa's Book: Why the Planet is Heating Up
What's more, while rainwater replenishes most underground aquifers, some critical underground sources of water aren't recharged by the normal water cycle. Known as fossil aquifers, these consist of water that was deposited millions of years ago and include two key water sources—the deep aquifer under the North China Plain and the Ogallala aquifer that waters much of the northern Great Plains of the U.S.—that are now becoming pumped dry. As a consequence, what we are seeing is what water experts call the end of "stationarity—the idea that natural systems fluctuate within an unchanged envelope of variability," notes Gerald Galloway, a civil engineering professor at the University of Maryland and a leading expert on water resources management in a warming world, and we're headed towards a "new normal" for which the past offers little guidance.
Although recent droughts have been disastrous for ranchers and farmers in the U.S., Americans still remain somewhat insulated from the full force of climate change and the projected food shortages. But not for long: Agricultural areas throughout the Midwest and especially in California are threatened by the growing water insecurity that accompanies a warming world. The torrid summer of 2012, which came at the tail end of the warmest 12 months in the United States since record keeping began in 1895, may be just a prelude of the kind of dry conditions we'll see in the farming heartland as the world warms. The consistent triple-digit temperatures sucked up moisture from the air and the soil, creating a severe drought in more than half of the United States, one that was like a slow-motion train wreck—a "creeping disaster" in meteorologic terms—for farmers in America's Corn Belt.
Some places, most notably Las Vegas and Orange County, California, have instituted stringent water-management policies to prepare for a dryer future. But in general, experts say we're not doing nearly enough to avert disaster. "I think we're already unavoidably committed to some negative impacts of climate change because we've waited too long," Glieck told me. "We can move toward sustainable water management—and we will—but the question ultimately is: How much pain are we going to suffer because we're moving too slowly?"
Published on: August 19, 2013
Updated on: August 20, 2013