A large sea freighter completed a voyage through the hazardous Arctic Northwest Passage for the first time on Friday as global warming opens routes that mariners have wanted for centuries.

The 75,000 deadweight-tonne Nordic Orion, built in 2011, left the Canadian Pacific port of Vancouver in early September with a cargo of coking coal and is scheduled to arrive in the Finnish port of Pori on Oct. 7, according to AIS shipping data.

"The Northwest Passage is more than 1,000 nautical miles shorter than the traditional shipping route through the Panama Canal and will save time, fuel and reduce carbon dioxide emissions, but even more importantly increase the amount of cargo per transit 25 per cent," said Nordic Bulk Carriers, the Danish owner of the ship.

Harsh conditions in the Arctic sea route so far have limited shipping mostly to small cargo vessels and ice-breakers, which supply northern Canadian communities.

The 225 metre-long Nordic Orion, a panamax-sized ship, has a strengthened bulk to cope with floating ice.

It is currently off the western coast of Greenland, where it let a Canadian Arctic adviser off board at Nuuk in Greenland, its operator said.

The vessel is to deliver the coal to Ruukki Metals, a Finnish steel producer.

Many scientists say the melting of Arctic ice is a consequence of warmer temperatures caused by greenhouse gases emitted by burning fossil fuels, particularly coal.

In another development on Friday, leading climate scientists said they were more certain than ever that mankind is the main culprit for global warming.

As the ice continues to melt, some experts have estimated that shipping via the Arctic could account for a quarter of the cargo traffic between Europe and Asia by 2030.

Last November, Russian gas export company Gazprom made the first ever delivery of liquefied natural gas through the Arctic north-east route, sailing from Norway east to Japan.

Many maritime analysts have said, however, that large volumes of commercial shipping via the Arctic are at least 10 years away.