The Polar Sea, one of the Coast Guard's two heavy icebreakers, suffered extensive engine problems, which likely will take until next year to repair. The Polar Sea's sister ship, the Polar Star, is undergoing a major refitting, which will be completed in 2013.
Dana Goward, director of the Coast Guard Office of Assessment, Integration and Risk Management, said Tuesday that the lack of an operable heavy icebreaker could be "a huge problem" if an emergency arises, such as a passenger ship getting trapped in Arctic sea ice. Other Arctic nations would have to fill the void.
The sidelining of both heavy icebreakers comes as nautical activity increases in both polar regions. In the Arctic Ocean, climate change is causing sea ice to melt farther and farther north and increasingly opening the region to adventure cruises and oil drilling.
"The Arctic is getting to be a more hazardous place every day," Goward told AOL News. "It's more accessible, so there are more people up there. This reduces our capacity to respond to those kinds of situations."
The lack of an operable heavy icebreaker also reduces the Coast Guard's ability to conduct science missions and to back up naval operations in polar waters, should that become necessary. "The nation has an interest in maneuvering on the oceans' surface whether they are frozen or not," Goward said.
Other Arctic nations have much larger icebreaking fleets than the United States. As of last year, Russia had 25 polar icebreakers, including six active heavy icebreakers; Finland and Sweden each had seven icebreakers; and Canada had six, according to a March report by the Congressional Research Service.
The only Coast Guard icebreaker remaining in operation is the Healy, a medium icebreaker primarily used for scientific research. Built in 2000, it is more advanced than the Polar Sea and Polar Star but is not capable of undertaking many of the operations carried out by the heavy icebreakers.
In an emergency requiring a heavy icebreaker, Goward said, the United States would likely call on one of its better-equipped Arctic neighbors for assistance.
"On a national level, this eliminates the nation's only heavy icebreaking capability and seriously imperils our ability to respond to emergencies in ice-covered and ice-diminished waters," Sen. Lisa Murkowski, R-Alaska, said in a statement released by her office. "This could clearly impact our ability to preserve and protect U.S. interests in the Arctic."
Murkowski has introduced legislation to fund construction of two new Polar Class icebreakers.
Until now, the federal government's strategy has been to try to keep its two heavy icebreakers, both built in the 1970s, operating as long as possible.
However, this strategy did not take into account how quickly global warming would make Arctic waters more accessible to commercial activities.
Construction of a new icebreaker would cost about $1 billion, Goward said.
The breakdown of the icebreaking fleet has gone largely unnoticed with BP's catastrophic oil spill in the Gulf of Mexico. The Coast Guard is the lead agency overseeing the government's response to the spill.
The Polar Sea put to sea from its home port in Seattle for an Arctic deployment earlier this month but soon experienced engine trouble and turned back. An inspection found that 33 cylinder assemblies of the main diesel engines were showing signs of excessive wear.
The cutter, which was commissioned in 1978, was designed to last for 30 years. It was overhauled in 2006 with the intention of extending its service life until 2014.
The engine failure will prevent the icebreaker from undertaking its fall Arctic patrol and most likely will keep it from supporting Operation Deep Freeze, the resupply of McMurdo Station in Antarctica.
The Coast Guard has been warning for years that the nation's heavy icebreaking capability was at risk without major long-term investment.
Adm. Thad Allen, commandant of the Coast Guard, warned in 2008 that the country was at a "crisis point" in deciding whether to move forward with the construction of new vessels, given the years required to build a Polar icebreaker.
Last year he told Congress that the Coast Guard would need six icebreakers to meet the goal of having one continuously available in both the Arctic and Antarctic seas.
"The loss of the Polar Sea is all the more reason for Congress and the administration to refocus on the deteriorated state of the nation's icebreaker fleet," Murkowski said. "Ice-breaking capability is critical to our national security and America's energy security."