* Cross-the-pole route would be limited to light ice-breakers
* Arctic ice shrinkage speeding up as less sunlight is reflected
* Access to land areas diminishing as swampy land thaws
By Environment Correspondent Deborah Zabarenko
WASHINGTON, March 4 (Reuters) - The quickest way to get goods from Asia to the U.S. East Coast in 2050 might well be straight across the Arctic, where a warming climate is expected to open new sea routes through what is now impenetrable ice, a study reported on Monday.
Most shipping traffic between these two centers currently goes through the Suez or Panama canals, and that is likely to continue even as melting Arctic sea ice makes the far north more accessible.
But increasingly warm temperatures also could make the Northwest Passage north of Canada an economically viable shipping route. Now, it is passable only at the end of most summers. It could also open up a route directly over the North Pole by mid-century, according to research published in the Proceedings of the National Academy of Sciences Plus.
The Northern Sea Route, which mostly hugs Russia's northern coastline and is now a primary Arctic shipping route, would continue to be viable, according to research by Laurence Smith, a geography professor at the University of California-Los Angeles.
The transit across the Arctic would remain highly seasonal, limited to parts of September when the ice has shrunk and thinned to its lowest level.
Last September, the U.S. National Snow and Ice Data Center reported Arctic sea ice melted to its lowest recorded level. The Arctic is one of the fastest-warming places on Earth because of the so-called albeido effect, where sun-reflecting light-colored ice is frequently replaced by sun-absorbing dark-colored water. The more ice melts, the warmer things get.
Both the Northern Sea Route and the Northwest Passage would be accessible to ordinary ships in addition to light ice-breakers by 2050, Smith said in a telephone interview.
"Last year, nearly 50 ships went through the Northern Sea Route, but this work shows that there will be other technically feasible options which will be available," he said.
The across-the-pole route, which had never before been considered, would be available only to light ice-breakers capable of plowing through ice 3.9 feet (1.2 metres) thick.
Melting ice could make these Arctic routes more viable, Smith said.
For example, right now it makes no sense for any ship traveling between eastern North America and Asia to go via the Northwest Passage. The islands in the Canadian archipelago slow navigation, and the ice lingers there in a way that it doesn't along the Northern Sea Route. Even though the Northern Sea Route is a greater distance, it takes less time.
However, by 2050, using projections of global warming and Arctic ice loss, Smith said the Northwest Passage will be sufficiently navigable to make the trip from the North American east coast to the Bering Strait in 15 days, compared to 23 days for the Northern Sea Route, about a 30 percent time savings.
This is never likely to be a year-round proposition, since winter sea ice will always recur, Smith said. And as Arctic shipping lanes open up, land transportation in the far north is expected to suffer, as winter ice roads deteriorate. These ice roads are the only economically viable way to do heavy construction and remove ore in the far north, he said.
"The distances are vast, the landscape is boggy and wet and covered with lakes," Smith said. "We've done modeling of this as well and what you see is a shutdown of human access on land and an increase of human access in the ocean." (Reporting by Deborah Zabarenko; Editing by Marilyn W. Thompson)