When Cameron Dueck set sail to the Canadian Arctic to witness what he calls "the front line of climate change", he did so knowing he would have to brave seas that have killed scores of sailors and reduced men to cannibals.

For 450 years before the first successful voyage in 1906, people sought the Northwest Passage, a potentially lucrative shipping route linking Europe to Asia that would cut out the lengthy journey around the horn of South America.

Many died trying to find it, including Sir John Franklin whose HMS Erebus and HMS Terror attempted the fabled Passage in 1845 but sank without a trace. Their 129 men died eating each other on the unforgiving ice.

But by the time Dueck set off on his voyage more than 100 years later in June 2009, 35 sailing yachts had made the trip. The majority of those took place after 1990, made possible by a stark reality: the ice was now melting fast.

"I wanted to see something very few people have seen," Hong Kong-based journalist and sailor Dueck told AFP at the launch of his book about the voyage, "The New Northwest Passage" at the Royal Hong Kong Yacht Club last week.

"It was about finding out what climate change looked like for real. Not just in terms of what we're told by politicians, or what corporations say in their mission statements," he said.

The extent to which Arctic ice is breaking up is an illustration of the growing impact of climate change in the Poles, where temperatures are rising more quickly than the rest of the world.

"There has been no ice for up to a month in the last several years during the summer," Peter Semotiuk, a long term resident of the Canadian Arctic and an expert on sailing conditions in the area, told AFP by email.

Semotiuk said the 2011 season featured the highest number of yachts ever to complete the Passage, with 16 making it through --- more than double the previous year's seven.

"I do see the effect of less ice cover through the Northwest Passage route," Semotiuk said, adding that commercial shipping is also on the increase as the ice melts. "It seems the whole Arctic ice pack is affected."

Dueck and his three crewmates sailed the 40 foot Silent Sound 8,000 nautical miles -- or 15,000 kilometres -- from Victoria in British Columbia, up to Dutch Harbor in Alaska, through the Bering Straight, down into the Beaufort Sea before hitting the Davis Strait between Canada and Greenland.

What they found was startling.

While the loss of Arctic sea ice threatens wildlife such as polar bears, seals and walruses that depend on it as a platform for hunting, mating and migration, the human cost is less well charted, said Dueck.

He met Alaskan fishermen who sail the Bering Sea for fish and crabs, and who are increasingly joining the dots between disappearing ice, warmer temperatures and their own changing fortunes.

Then there is the Inuit -- who have been forced to change their lives due to the impact of climate change, from harvesting berries a month earlier than they used to, to ancestral hunting knowledge being reduced to irrelevance by the swiftly warming environment.

"They used to be able to read the ice -- look at wind, temperatures, the moon phase and understand when it was safe to be on the ice and when it was time to pack up and head to shore," said Dueck.

"But these days, they no longer trust the ice, or their traditional ways of reading the ice, because it is breaking up sooner and no longer according to the patterns they know."

While Dueck admits such anecdotal evidence has not been fully processed scientifically, "when every hunter you meet is saying the same thing, that tells you all you need to know".

Then there is a sociological impact. With climate change reducing the scope for traditional Inuit customs, younger generations face an identity crisis in a community already struggling with alcohol and other issues.

"They need to know who they are and why they are living there. Without that connection to the land they lose their identity, their pride," said Dueck. "The hunting is a kind of safety net and when that's eroded, the communities go astray."

While the ice is a life-giver for the Arctic and its inhabitants, for Dueck it was a constant threat capable of crushing the hull of his boat and putting his crew into the water.

The dangerous voyage has been made by far fewer people than have climbed Mount Everest, but numbers have been rising each year since 2007, when the Passage was open water from East to West for the first time in living memory.

Dueck and his crew spent four months and four days at sea -- and getting on with each other was as much a challenge as navigating through unpredictable ice patterns.

"When you're on a 40 foot boat at sea, there's not much you can do if you don't like each other," said Dueck.

One of the crew did jump ship after a month as the pressures -- from on-deck showers using buckets of freezing water to the exhaustion of sailing through constantly moving ice -- took their toll.

"You don't stop, you keep going 24 hours a day," said Dueck. The crew took three-hour shifts at the helm, averaging a total of 8 hours on deck a day in freezing rain, fog and punishing winds.

"In early summer the midnight sun was still high enough that we could see. As summer progressed it got darker and darker.

"For the last half of our time above the Arctic Circle we were sailing through dark nights, so we had the terror of knowing that if you strike ice you're likely to end up in your lifeboat. That is terrifying, especially during storms."

Perhaps equally challenging is the re-entry into society at the end.

"Any time you come back from sea it's astounding how loud and how busy life on land is, said Dueck. "That was something you'd cherish in the Arctic. Time at sea to reflect. Time to think."