An international group of scientists predicts the Arctic Ocean could be largely ice-free by 2050, making trans-Arctic shipping a common practice. Doug Schneider of Arctic Science Journeys Radio reports from Alaska on one possible result of a warmer climate in the currently-frozen far North.

Explorer Sir John Franklin was 200 years ahead of his time. In 1845, Franklin set out from England to find an ice-free route across Canada's Arctic Ocean: the so-called Northwest Passage. Franklin never found a way through. Instead his ship became trapped in the ice. He and all 128 crewmembers died during one of the worst Arctic winters on record.

But if a team of international scientists is correct, traversing the Arctic Ocean could become routine as early as 2050. That's because scientists believe much of the Arctic Ocean will be ice-free in summer by then, thanks to an Arctic climate that continues to become warmer. The bold prediction will likely be included in an Arctic Climate Impact Assessment to be released at an international conference in Iceland in November. "The opening of the Arctic is perhaps one of the major, or the major impact that we have found in this assessment," said Gunter Weller, executive director of the Arctic Climate Impact Assessment.. "The magnitude of the expected change in sea ice conditions is pretty extraordinary."

More than 250 scientists from around the Arctic spent four years compiling the report for the Arctic Council, an organization of government officials, scientists and indigenous people from Canada, Denmark, Finland, Sweden, Iceland, Norway, Russia and the United States.

The report is expected to conclude that the Arctic is undergoing dramatic environmental change as a result of a climate that has warmed an average of five degrees in recent decades. Among the changes are disappearing sea ice, melting permafrost and glaciers, and the colonization of the tundra by trees and shrubs. The report also draws on five separate computer models to predict the Arctic's future climate. Weller says that while each model offers somewhat different scenarios, they all point to an Arctic with much less ice and snow in coming decades.

"There will be melting of snow and ice of every form, including sea ice, also the melting of glaciers and the thawing of permafrost," said Mr. Weller.

Lawson Brigham ? oceanographer, former U.S. Coast Guard Captain, and Alaska Office Director of the U.S. Arctic Research Commission ? says that while all the models predict easier shipping within this century, one model predicts an ice-free Arctic basin as early as 2050.

"We're looking at maybe even Trans-Arctic shipping by mid-century," he said. "That doesn't mean directly through the North Pole, but it might mean north of the island groups north of the Canadian Archipelago. So you'd essentially cross the central Arctic Ocean."

Mr. Brigham said any Canadian sea route likely will be blocked by disintegrating glaciers and seasonal sea ice through the rest of the century. A far more likely passage will be the so-called Northern Sea Route, along Russia's Arctic coast. "It is the Northern Sea Route on the Russian side where in fact the action is; where it has been and where it will be in the future. All the satellite trends and information points to more open Russian Arctic coastal seas. Six-month navigation seasons are within the realm of possibility for large cargo ships and tankers."

There is of course a significant downside. Scientists say a warmer Arctic will dramatically alter the region's ecosystem. At least one Canadian researcher predicts polar bears, which need sea ice to hunt seals, will be all but extinct by the end of the century. The loss of sea ice also will likely alter migration patterns for whales, and force seals and walrus to search further for ice to haul-out on.

These environmental changes are expected to cause hardships for the Arctic's indigenous people who depend on the land and sea for food. And, scientists say, melting Arctic permafrost and increased erosion will cause billions of dollars in damage to coastal communities, roads, homes and other infrastructure across the Arctic.