HANOVER, New Hampshire (Reuters) — Global warming, blamed for melting polar bears’ icy Arctic habitat, could be a boon to the shipping and oil industries in the far north, according to a new US report.The dramatic decrease in sea ice above the Arctic Circle means formerly impenetrable shipping routes are now or soon could be open for much of the year, the US Arctic Research Commission said in a report released last week at a summit of Arctic scientists in Hanover.

“Diminishing sea ice conditions in the Arctic Ocean are changing ecosystems, most conspicuously for polar bears,” said the commission’s report, prepared for President Bush and Congress.

“This also creates unprecedented access for ships that will bring people to the north, and will significantly shorten global marine transportation routes,” it said.

The cost difference is dramatic, according to Mead Treadwell, the commission chairman. The estimated cost of transporting a shipping container between northern Europe and Alaska’s Aleutian Islands is about $500 he said; moving the same container between Europe and the port of Yokohama, through the Suez Canal, costs about $1,500.

Beyond shipping, less sea ice means easier access for offshore oil exploration and drilling in the Arctic, which is thought to contain about 25 percent of the world’s remaining oil and gas reserves, the report said. It also noted that about half of the fish consumed in the United States comes from the Bering Sea off the Alaskan coast.