WASHINGTON — The U.S. Coast Guard’s No. 2 commander said refurbishing the aging Polar Sea icebreaker now idled in Seattle would allow it to meet the nation’s Arctic mission for the next decade until a replacement ship can be built.

The comment Wednesday by Vice Admiral Peter Neffenger is the Coast Guard’s clearest endorsement yet for fixing up the 1970s-era Polar Sea, which in 2012 was on the verge of being decommissioned and used for spare parts for its sister ship, the Polar Star.

In an interview at a seminar on Arctic shipping hosted by the Royal Norwegian Embassy in Washington, D.C., Neffenger said salvaging the Polar Sea would be a “viable alternative” to a new heavy-duty icebreaker that could cost up to $1 billion.

“We think that would be adequate (to meet the mission) for the next 10 years,” Neffenger said.

In March, then-Admiral Robert Papp offered a more tepid embrace during a congressional hearing. Papp testified that returning the Polar Sea to service was an option, but noted for the record that “I didn’t say a good option.”

Neffenger, who began serving as vice commandant in May, said retrofitting the Polar Sea would be a stopgap solution. It can take a decade to build a new icebreaker, and the United States needs to act quickly.

“That window is now,” he said.

The Polar Sea’s fate and the future size of America’s icebreaker fleet are among the key policy questions for carrying out the nation’s Arctic strategy, a blueprint for asserting U.S. interests as warming polar temperatures open up Earth’s northernmost region to increased traffic and exploration.

The decisions also would affect Seattle, home to the Coast Guard’s three-ship icebreaker fleet. In March, U.S. Sens. Maria Cantwell, D-Wash., and Mark Begich, D-Alaska, introduced a bill to refurbish the Polar Sea at a cost of about $100 million.

The Polar Sea and its twin, the Polar Star, are well past their 30-year service life. The Polar Star emerged from a four-year, $57 million overhaul in late 2012 from Vigor shipyard on Seattle’s Harbor Island.

The Coast Guard has said it would prefer to build new icebreakers, but it lacks the budget. An amendment in the 2014 defense bill written by Cantwell, Sen. Patty Murray of Washington and the Alaska senators to authorize construction of as many as four heavy-duty icebreakers was dropped without a vote.

The third icebreaker, the Healy, is a researcher ship whose steel hull is designed to break through thinner ice.

Cantwell, in a statement Wednesday, welcomed the Coast Guard’s support for refurbishing the Polar Sea. She urged the Obama administration and Congress to put up the money not only for that, but for new ships as well.

U.S. Rep. Rick Larsen, D-Everett, who spoke at the Arctic seminar, warned that the United States is failing to fully prepare for the economic, environmental and security issues brought by changing polar climate.

Larsen noted that Russia, which has the world’s largest government-owned icebreaker fleet, with 22 vessels, is building another ship that will be bigger than any. Russia also has moved aggressively to map the sea floor to claim rights over its Arctic continental shelf that extends beyond the 200-mile territorial zones.

Countries like Russia, Norway and even non-Arctic states like China are investing in equipment and research to profit from new shipping routes and potential oil and gas exploration, Larsen said.

He said it was only in 2009 that a Russian icebreaker guided two German ships in making the first commercial passage through the Northern Sea Route linking Europe and Asia. Last year, 71 vessels made the journey amid melting ice through the route, also known as the Northeast Passage.

Yet many Americans’ view of the Arctic, Larsen said, is that “it’s way up north and there isn’t much going on up there.”

Such an attitude means “we’ll miss out on the chance to take advantage of these opportunities and to hedge the dangers they present,” said Larsen, who serves on the House Subcommittee on Coast Guard and Maritime Transportation.

Among other things, Larsen is pushing to create a post for ambassador-at-large for Arctic affairs. The United States is the only country among the eight-member Arctic Council, an international forum, without a high-level representative to the group.

Kyung Song: 202-383-6108 or ksong@seattletimes.com. Twitter: @KyungMSong