(CNN) -- Climate change is altering diets and lifestyles among Inuit people, according to a scientist who has studied the human face of global warming in the Arctic.

Barry Smit, a professor at the University of Guelph, Canada, has spent five years leading research projects into how melting ice and changes in wildlife habits are impacting the lives and livelihoods of far northern communities.

Among his most striking findings was that increasing difficulty in hunting for traditional food was leading to much more junk food in the Inuit diet.

"People looking at the health of the Inuit have demonstrated that the traditional diet, which is almost exclusively raw meat, is in fact very healthy for them," Smit said. "But because of the new difficulties hunting, people are adapting their diets to what's available in the stores.

"The stores only have food that's easy to transport and doesn't perish, so there are no vegetables. The young people are increasingly eating highly processed junk food, so we are seeing more teeth problems and obesity."

The difficulties in hunting are caused by shifting ice and changing migratory patterns among animals such as seals, walrus, types of whales and polar bears, which form a large part of the traditional diet, Smit said.

He also noted that the shifting ice made hunting and traveling more dangerous.

Smit said: "Ice is fundamental to their livelihoods and culture. Most of their activities involve traveling on the ice.

"Over the past decade or so, they have noticed that the behavior of the ice is changing, so their traditional roads are not as safe as they used to be."

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He added: "They could be hunting on the edge of the ice and whole blocks of ice break off and drift out to sea, so they have immediate safety concerns."

This unpredictability undermines traditional knowledge of safe routes across the ice.

"There are social implications because the respect for elders has been maintained by their wisdom about when and where to travel on the ice," said Smit.

"But now elders will say it's safe to travel to a particular place at a certain time, and people have problems there. That undermines the traditional knowledge of the elders."

He added that houses built on permafrost were tipping as the ice shifted.

Tristan Pearce, one of Smit's researchers, also from the University of Guelph, who spent time with communities in Northwest Territories, Canada, said: "Due to thin, unstable, temporary sea ice cover that is vulnerable to winds and currents, aolagots (open boats) are becoming more common in winter months presenting new hunting opportunities and dangers to hunters."

He added: "Several studies project that the Arctic Ocean may become seasonally ice-free by the year 2040 or even earlier."

Smit studied Inuit as part of a Canadian project called ArcticNet, and collaborated with scientists from other Arctic regions as part of the International Polar Year.

He led a team of researchers who built up-close relationships with communities in the Arctic, and invited people from those communities to join the project as co-researchers.

Smit said: "We have been to document from the perspective of people who live in the Arctic how conditions are changing and how they are dealing with it to get a sense of how they might adapt in the future."

Four million people are estimated to live in the world's Arctic regions, across Canada, Alaska, Greenland, Norway and Russia, Smit said. In the far northern Arctic regions of Canada, the population is 85% Inuit, he added.

Smit said the average temperature rise since pre-industrial times was conventionally estimated at 1.2 degrees Celsius globally, and 2-3 degrees Celsius in the Arctic.

The United States' National Snow and Ice Data Center reported that the extent of Arctic sea ice cover at the end of November this year was the second lowest on record, and 12% below the 1979-2000 average for November.

"You can look at a big map of the world and see the changes from climate change, but we are trying to put a local human face on this and find how people are affected and how they deal with it," said Smit.

A team of scientists, lead by Professor James J. Corbett of the University of Delaware published a paper in October warning that increased shipping as new ice-free sea routes opened up would further add to climate change in the Arctic.

Smit said opinions among the communities were divided on the implications of the opening up of shipping routes through the Arctic Ocean, speeding up oil, gas and mineral exploration and tourism.

"If you look over the next couple of decades, the transformation will be huge. It won't be an Arctic environment at all and people will have to modify their way of life completely," he said.