HOW HE SEES IT Is there enough to meet the demand?

By BILL McKIBBEN
WASHINGTON POST
One question naturally arises when you hear that 67 million more people are on the way: Do we have enough to go around? Last year raised worries about "peak oil," the notion that the glass of crude may be half empty, bringing with it higher prices, increased jousting with countries like China, maybe even threats to the supremacy of the sprawled-out American suburb. Now get ready for peak water, and even peak food.
America is, on average, a damp nation -- the lower 48 states see 4,200 billion gallons of rainfall every day. But averages deceive; water is in short supply in the Southwest, where growth is fastest and rivers are already over-tapped. Even back East, we use so much water that supplies can run short. The Ipswich River near Boston now "runs dry about every other year or so," according to Sandra Postel, director of the Global Water Policy Project. "Why? Heavy pumping of groundwater for irrigation of big green lawns."
In drought years like 1999 or 2003, Maryland, Virginia and the District have begun to fight over the Potomac -- on hot summer days combining to suck up 85 percent of the river's flow.
Just as gasoline shortfalls have led to new interest in hybrid cars, aggressive conservation measures could alleviate some of the water deficit -- Boston already uses 31 percent less water now than it did in the 1980s. And in the West, where irrigation uses up 80 percent of water supplies, reducing subsidies that keep water prices artificially low would help. But Postel cautions that "water savings on farms will simply go to fill urban swimming pools" unless governments establish strict allocation policies designed to make sure that streams and wetlands get the water they need.
American waistlines
Talk of irrigation raises the question of food. To judge by simply looking at American waistlines, we have more than enough -- and the fertile midsection of the country means we're in better shape than the rest of the world to keep growing our dinner. But overall food production around the world has begun to sputter; after fast growth in the decades following World War II, says Lester Brown of the Earth Policy Institute, the last 10 years have seen a steady erosion in the amount of grain grown per capita. And since wheat and rice and corn are all world markets, the need for imports elsewhere could drive up the cost of food here at home. The Chinese, in particular, are constantly converting farmland to factory sites (even as they learn to eat more meat), and they have plenty of American cash stored up to pay for any shortfall. But if they do so, the first casualties will be the world's really poor nations, already reeling from increases in the price of fuel.
All these fairly grim projections may, in fact, be optimistic. They assume a physical world that operates in the future the way it has in the past. But, as this year's outlandish hurricane season hinted, that may be a sucker's bet. Global warming will almost certainly stress water supplies in dramatic ways: In the western mountains, for instance, where the snowpack serves as a natural reservoir for the winter's precipitation, more rain and earlier melt will mean less storage. The same rise in temperatures will almost certainly make farming harder. Earlier snowmelt means more parched fields by midsummer -- and when the temperature rises into the mid-90s for long stretches, crops like corn begin to have trouble fertilizing. The summer of 1988 was the warmest yet across America's grain belt, and yields dropped as much as a third.
So far we've always innovated our way to plenty, and we may again. The high-tech gurus talk about spreading Israeli drip-irrigation techniques, for instance. But there's no question that by 2030, limits will be pinching much more tightly. As we're warned at the bottom of all the mutual fund ads, "past performance is no guarantee of future results."
X Bill McKibben is an environmentalist and author whose most recent book is titled "Wandering Home."