Maine’s U.S. Sen. Angus King returned from a fact-finding trip to Greenland on Thursday determined to push for more icebreakers to clear emerging Arctic trade routes, some of which could be built in Maine.

The United States has only one working heavy icebreaker capable of clearing shipping lanes through Arctic waters as the ice sheet there melts, while Russia has at least a dozen, King said. Icebreaking abilities are essential in a warming world, he said.

Arctic trade could play a big role in the Maine economy, with Maine ports being the first ones reached by ships traveling east through the Northwest Passage, King said. So icebreaking is important to the state’s economic future, as well as America’s, he said.

U.S. and Danish defense and meteorological delegations survey an iceberg array off the western coast of Greenland. Maine’s U.S. Sen. Angus King took part in the three-day fact-finding mission.

President Obama has set aside money for another heavy icebreaker to be built in the future, but by the time it is done, the existing ship will probably need to be retired, still leaving the United States with just one, King said.

King spent three days touring the massive, mostly icebound island, meeting with government officials to learn about impacts of warming Arctic waters. He visited Greenland’s largest glacier and surveyed the increasing number of icebergs.

“What’s happening there is amazing and scary,” King said of Jakobshavn Glacier. “The glacier has moved as much in the last 10 years as it has in 100 years before. That summarizes what has been happening as a result of climate change.”

When the Greenland ice sheet melts – and all science says that it is doing just that, it is just a question of how fast, King said – the sea levels across the globe will rise by 24 feet, King said. Scientists predict the sea will rise about a foot in the next 15 years or so, he said.

“A foot doesn’t sound like that much, but if you add a foot to high tide surge or a storm it really makes a difference,” King said, citing Portland’s Old Port, which was built on fill, as a prime example of a port in need of infrastructure improvements to cope with climate change.

Sen. Angus King, Coast Guard Commandant Paul F. Zukunft and Danish defense and meteorological officials work Monday during a three day fact-finding mission to Greenland, examining the environmental and security implications of the warming Arctic climate.

Speaking at the Portland International Jetport after getting off a plane, King said he wasn’t certain exactly how much the trip cost. The Coast Guard was going anyway, he said, so the only cost to taxpayers was lodging for him and two staff members.

King was the only member of Congress to participate in the fact-finding mission. Alaska Sen. Lisa Murkowski was supposed to go, but had to cancel, King said. Commandant of the Coast Guard Adm. Paul F. Zukunft also attended.

King said he talked with Zukunft about a pending $10 billion contract for Coast Guard cutters, which is due to be awarded in the next month or two, but he didn’t learn anything new. Bath Iron Works is a finalist for the contract.