Arctic ice showing its cracks

ICEBREAKER CHANNEL, Northwest Passage — Satellite imagery has shown that the Arctic ice cap is thinning and already is nearly 30 percent smaller than it was 25 years ago. In the winter of 2004-05, the Arctic's perennial ice, which usually survives the summer, shrank by 280,000 square miles, the size of Turkey. This past August, a crack opened in the ice pack from the Russian Arctic to the North Pole, an event never seen before.

Arctic ice reflects sunlight; its absence may accelerate global warming. The intricate chemistry that occurs in the rich Arctic waters could go haywire with unaccustomed heat and sunlight. Whole species seem destined to disappear while others move northward in their place. Inuit who thrived here for millennia are finding the thin ice and changed wildlife inhospitable.

"People tend to think there's not much life in the Arctic. But it's an incredibly diverse ecosystem," says Gary Stern, the chief scientist on the Amundsen. He was aboard when the ship was deliberately frozen in Franklin Bay in 2003. They spent the long winter doing experiments on the ice. The Amundsen has a pool to access the water through the hull; it became a favorite hangout for ringed seals.

This year is "amazing. No ice," Stern says.

Estimates vary widely on when the passage will be open to shipping all summer because of the ceaseless warming. The Canadian Ice Service conservatively predicts the southerly drift of even a shrunken ice pack will keep the passage clogged for most of this century. Other experts predict it will be open as soon as 2020; Canada's defense agency says 2015. Those who visit regularly say the evidence is before their eyes.

"You can see it. You come every year and you see less and less ice," says Marie Emmanuelle Rail, 30, a researcher who has been working in the Arctic for five years.

ArcticNet, the Canadian university consortium organizing the voyage, believes the interwoven effects of global warming may be revealed as shipmates, from students to noted scientists, discuss their work over galley tables. The vast Arctic out the portholes is a constant reminder of the stakes.

"It's huge. It's all about saving the world," says Stephane Thanassekos, 26, a French researcher pursuing his doctoral degree at Laval University in Quebec City.

A scientist with infectious enthusiasm, Thanassekos operates a contraption that looks like an automatic milker from a dairy barn. It has 24 cylinders that can each be controlled to collect water at a different depth, up to 3,000 feet, and a bevy of sophisticated probes.