Climatology: The Iceman

Not so long ago, Ohio State University glaciologist Lonnie Thompson was standing on the summit of East Africa's Mount Kilimanjaro, watching his drilling team bring up a cylindrical core of ice. With eyes honed by a quarter-century of experience, he saw immediately that the core's glassy surface was riddled with holes--not the little round holes formed by trapped air bubbles but gaping conduits that could have been excavated only by running water. It was not an encouraging sign.

Indeed, the holes confirmed what Thompson already strongly suspected--that the snow-clad ice fields of Kilimanjaro, immortalized by Ernest Hemingway as "great, high and unbelievably white," are undergoing such rapid warming that they are likely to vanish altogether in another 15 years. And if that happens, Thompson realized, then all that will remain of Kilimanjaro's crowning white glory will be whatever fragments he and his colleagues managed to bring back to Ohio State and stash in their Arctic-cold freezer.

In that much, at least, Thompson and his team succeeded. The ice from Kilimanjaro is now back in Columbus, Ohio, along with numerous other specimens wrested from earlier expeditions to the impressively high mountains that ring the tropics. During the next five years, Thompson plans to retrieve still more. If it weren't for his work, the world might forfeit a natural library filled with priceless archives. For like the rings of long-lived trees and the accreted layers of massive corals, ice encodes surprisingly precise records of swings in temperature and precipitation over the centuries. Once that ice starts to melt, however, those records might as well have been written in water-smeared ink.

Fortunately, Thompson has already "read" many of the records that are now gravely endangered. From the Quelccaya ice cap in southern Peru, for example, he has reconstructed a 1,500-year sequence of swings from wet to dry that eerily track the rise and fall of ancient civilizations. From glaciers on opposite sides of the world, some in the Andes, others in the Himalayas, he has built a strong case that the tropics were far colder 20,000 years ago, at the height of the last ice age, than most scientists thought possible.

Thompson is an important figure in part because what he does is unique. While most glaciologists focus on polar regions, he has targeted the long-neglected ice fields of the tropics. "Lonnie went against the grain," says influential paleoclimatologist Wallace Broecker of Columbia University, and in so doing, Thompson has helped overturn the long-standing belief that the planet's so-called Torrid Zone is merely a passive responder to swings of climate, as opposed to an active participant.

Thompson grew up on a small farm in rural Gassaway, W.Va. The middle child of three, he was the first member of his family to receive a university degree. Neither his father, an electrician, nor his mother had more than an eighth-grade education, though his mother later went back to school. Today Thompson sees his family's struggle to eke out a living as a source of personal strength. Among other things, that strength has helped inure him to the physical hardships--frostbite, altitude sickness, barely palatable food--that he routinely endures in the field.