Eighteen ships have travelled through the Northwest Passage and cleared customs in Inuvik, N.W.T., so far this year. By comparison, only seven did the same in 2009, according to the Canada Border Services Agency. (CBC)

The number of ships travelling through the Northwest Passage has doubled this year, prompting at least one Arctic sovereignty expert to call for more enforcement in the increasingly ice-free Arctic waterway.

The Canada Border Services Agency says 18 ships have cleared customs in Inuvik, N.W.T. — at the western end of the Northwest Passage — so far this year, and the navigation season is not even over yet. By comparison, only seven ships cleared customs there in 2009, according to the agency.

"It is a little bit tricky — lots of fog and ice," Börje Ivarsson, a Swedish adventurer who just finished a two-year journey from Russia to Inuvik on a 30-foot boat, told CBC News.

"It's quite a shortcut if you're living in the north of Europe to get over to Alaska," Ivarsson said of the Northwest Passage. "It's a good adventure, too."

The increase in marine traffic is largely a result of climate change opening up the passage, said Rob Huebert, the associate director for the Centre for Military and Strategic Studies at the University of Calgary.

Huebert said many people have talked about the Northwest Passage's potential for years, and now it's starting to happen.

"I think that we'll often go back to 2010 and say that was the turning point, that was the time when it turned from theory to actuality," he said.

Marine traffic up across Arctic

Huebert said marine traffic is going up across the circumpolar Arctic, including Russia, Norway and Greenland. Canada can expect the rising trend to continue, he added.

"We're starting to see increased economic activity within the northern region. As soon as you start having increased activity, you start seeing more shipping," he said.

Huebert cited the tourism trade as an example, saying more cruise ships and tour vessels have been coming north as Arctic waterways opened up in recent years.

"Greenland, for example, went from having no tour vessels to numbers of between 88 to 200," he said.

"We've lagged behind because we've had worse ice conditions than what Greenland has, but one can certainly look to them to sort of see our future."

Given the increase in traffic in the Northwest Passage, more Arctic patrol vessels and better surveillance are needed to enforce and protect it, Huebert said.

"As more shippers come into the Arctic, I think it behooves us to be prepared for the fact that there may, in fact, be some who may not necessarily want to abide by Canadian jurisdiction," he said. "That means better surveillance, that means better instrumentation."

Huebert also called for better port infrastructure in communities along the passage, improved search and rescue capability, and better environmental response systems in the event of oil spills.

A report released last week by the University of Alaska in Fairbanks urged policymakers in Arctic nations to create an international polar marine code, establish full tracking of commercial ships in the Arctic, and work out an Arctic search and rescue agreement, among other priorities.