A TIME correspondent visits Ice Station SHEBA, an isolated, expensive and unsettling probe of the disappearing Arctic ice cap

By ANDREW PURVIS

he ocean view is lousy, the weather is terrible, and the polar bears are very uncivil. This spot on the permanent Arctic ice pack, some 500 km north of Barrow, Alaska, and just east of Russian territorial waters, is not exactly the ideal place to beat the summer heat. But for some of the world's top polar scientists, there's no more important location on the planet. It's here that the Canadian Coast Guard icebreaker Des Groseilliers can be found after eight months of drifting in the vast crumpled mass of ice that imprisons the top of the world.

This is the first time in more than 100 years that a ship has locked itself into the ice cap for scientific reasons. A century ago a single Norwegian named Fridtjof Nansen spent three years aboard his small wooden ship, the Fram, as the floe carried him farther north than anyone had gone before. The crew of Des Groseilliers is larger and much better equipped, and the goal is appropriate for the end of the millennium: to see if the vital ice cap is melting. A definitive answer will take time, but initial results are worrisome.

Sponsored by the U.S. National Science Foundation, among others, the $40 million, six-nation mission is the largest research expedition ever to venture into the extreme north. Ice Station SHEBA, as it is known (for Surface Heat Budget of the Arctic), is attempting to assess the potential impact of the high Arctic accumulation of greenhouse gases in the atmosphere. The aim is to gather enough data from a single point on the pack, the clouds above and the ocean below to piece together a computer model that will project the complex climate of the region over the next 50 years. Researchers already know that the pack, equivalent in area to the continental U.S., is sensitive to slight changes in solar radiation and is critical to oceanic ecosystems worldwide. Scientists also know that the pack has been shrinking 2% to 3% a decade since the 1970s.

Whether and at what rate that melting trend will continue are urgent concerns. The polar cap is believed to act as a kind of giant conveyor belt, cycling nutrients and fresh water to southerly oceans. Scientists can only guess at the effect of a large-scale melt, but no one doubts that the disappearance of the cap in as few as 50 years, as some researchers have predicted, would be catastrophic. "We don't have to go to the worst-case scenario to get pretty frightening," Mike Ledbetter, director of Arctic research at the National Science Foundation, told TIME as he yanked on a pair of insulated boots aboard ship.

Supersensitive instruments around Des Groseilliers suck up information at a prodigious rate. A laser-driven radar dish, known as "lidar," can take up to 2,000 readings per sec. in the upper atmosphere, measuring everything from wind speed to humidity. A foot-long, remote-controlled submarine, called a yo-yo, bobs for temperature, salinity and ocean-current speed measurements all the way down to the ocean floor. "We're literally swimming in data," gloats University of Washington engineer Roger Anderson.

It may be five years before the data form definite patterns. But there are early indications of significant recent melting. The first scientific paper from the expedition, published in May in the journal Geophysical Research Letters, reports that a lens of relatively fresh water just beneath the polar ice is more than twice as thick as it was 20 years ago and appreciably warmer. The scientists say this could indicate that a comprehensive melt is under way. Some anecdotal evidence supports that view. Ice specialists working near the ship this summer have found the seasonal floes to be thinner than usual, building to a maximum of 2 meters by late spring rather than the customary 3 meters. At the very least, says Terry Tucker, who works at the U.S. Army's Cold Region Research Lab in Hanover, New Hampshire, "it means that last summer was a heckuva summer. Taken together with other observations, I would say that something is really happening here."

Even though the weather is unusually hot, the SHEBA researchers are doing their detective work in one of the most hellishly cold places on earth. High arctic temperatures in February averaged