Shippers and carriers that use ocean shipping lanes in Canada's far north may be forced to make some last-minute routing adjustments next summer. A giant iceberg that's now mired in sea ice in the Arctic Ocean is expected to float westward toward shipping lanes once the warmer weather arrives.

The chunk broke off from an ice shelf near Canada's Ellesmere Island in 2005 but wasn't detected until late last year. It was the largest break in three decades, researchers say, setting an ice mass that's bigger than Manhattan adrift in the Arctic Ocean. When sea temperatures rise and the massive chunk once again floats free, it could disrupt oil and gas exploration as well as shipping in the region.

"The risk is that next summer, as that sea ice melts, this large ice island can then move itself around off the coast," says Luke Copland, a professor at the University of Ottawa and an expert on ice masses. "One potential path for it is to make its way westward toward the Beaufort Sea, and the Beaufort Sea is where there is lots of oil and gas exploration, oil rigs, and shipping."

The giant iceberg poses a bigger threat to fixed oil drilling rigs than to shipping lines, which will be able to reroute ships around it if necessary. Copland says that in the event the ice mass gets caught up in shipping lanes, the Canadian Ice Service will monitor its progress so that it can transmit location updates and recommend detour routes to shipping companies.