How To Beat The Heat

These forecasts illustrate the hidden power of the deceptively small temperature changes that climatologists expect. The IPCC warns that the world could be, on average, 1.8 to 6.3 degrees warmer by 2060. But some regions will warm much less and others, especially the interiors of northern continents, will warm much more. (That's how you get an average, after all.) The United States is facing a temperature rise of 5 to 10 degrees by 2060, with 10 to 30 percent less moisture in the ground during the summer growing season. And small temperature increases ""become amplified when you run them through biological systems,'' says Daniel Hillel of the University of Massachusetts. The eggs of freshwater fish, for instance, are exquisitely sensitive to temperature. With a rise of 6 degrees, brook trout would be unable to live in more than half their southern Appalachian streams. Too bad for local anglers. Smallmouth bass and yellow perch, though, would expand their range across Canada by 300 miles. Fishermen there would come out winners.

Those are the kinds of regional effects that researchers and policymakers are now trying to forecast. Last month more than 400 scientists, economists, physicians, resort owners, fishermen, farmers and business people met in Washington to discuss how global warming could affect everything from ski resorts in Vermont to oystering in Puget Sound. And this week in Kyoto, the IPCC will distribute a 600-page report on how climate change will harm, or help, specific regions worldwide. At the end of a paragraph listing all sorts of ""potentially irreversible'' adverse effects, the report acknowledges that ""some effects of climate change are likely to be beneficial.''

For every 1.8-degree rise in average temperature, heating bills will fall 11 percent in the United States. Winners: people in northern towns like Green Bay, Wis., who will also save on snow-removal costs. But frigid temperatures have kept land in the Alaskan and Siberian Arctic as hard as rock. Now the permafrost in both places has begun to melt to the consistency of New England clam chowder. Alaskan towns are already spending up to $3 million to shore up every mile of sinking road. Another loser: Glacier National Park (1995 tourist spending: $80 million), all of whose glaciers, absent a miracle, will be gone by 2030.

Since what will happen to the world overall is still uncertain, what will happen to a particular region is even iffier. But one outcome--sea-level rise--is a pretty sure bet. Unlike weather, sea level does not depend on clouds, chance or mischievous jet streams. And it is already happening: seas have risen by almost 10 inches this century, and more thermal expansion of seawater and glacier melting will push oceans up even farther. IPCC calculation: 23 inches by 2100, half that by 2050. The United States could lose 10,000 square miles of coastland with a two-foot sea-level rise. Smith Island in Chesapeake Bay, home to an isolated community that still speaks in the Elizabethan lilt of their ancestors, may disappear beneath the waves. Sandy beaches in Monmouth County, N.J., and on New York's Long Island slope so gently that a sea-level rise of only one foot--likely by 2050--will inundate 100 feet of beach. One third of the Everglades sits less than 12 inches above the Atlantic; since the resident and rare Florida panther is not known for its breaststroke, it will face extinction. Still, communities can save shorefront developments by building sea walls. Much of New Orleans, and San Jose and Long Beach, Calif., are already below sea level, but they are still inhabited cities and not Atlantises. To protect Manhattan's 29-mile waterfront from a one-foot rise would cost just $30 million. Winner: construction crews.

But sea walls are no panacea. In Puget Sound, an additional sea-level rise of 14 inches will turn 40 percent of the mud flats, where shellfish spawn, into ocean floor, where they can't reproduce. Residents of Camden, N.J., and farmers in the central part of that state may find that the aquifer that supplies drinking water and irrigation has become brackish because rising seas push saltwater farther up the Delaware River, which recharges this aquifer. Miami's Biscayne aquifer is similarly vulnerable to such ""salt intrusion.'' Winner: sellers of bottled water. Losers: farmers, who can't use saltwater on their crops . . . and can't afford Evian for them, either.

Cathy Gill runs a commercial marina with her husband in Crystal River, on Florida's Gulf Coast. ""We've heard all about'' global warming, she says. If seas rise 10 inches (at the low end of projections for 2050), the waters will inundate enough of the Louisiana wetlands--where brown shrimp spawn--to slash the shrimp catch in the gulf by 25 percent. Add shrimpers to the list of potential losers in the greenhouse sweepstakes. But fishermen off Los Angeles are now hooking expensive yellowfin tuna thanks to warmer Pacific waters, like those brought by El Nino. In a warmer world, suspects climatologist Kevin Trenberth of the National Center for Atmospheric Research, El Ninos will be more common. Put southern-California fishermen on the list of potential winners.