Sarah James, a member of the Gwich'in nation, said climate change had brought formerly unheard-of species -- black bears, beavers and cottonwood trees -- to the small community of Arctic Village, Alaska, where she lives.

It also changed the way wolves hunt for food, forcing them to band together in a pack and prey on dogs tied up outside villagers' homes instead of hunting solo in snow-covered areas, James said.

That is because the snow failed to come as expected last September; it finally arrived in December, but by then the ground was frozen deep and solid, James said in an interview.

"The wolf, it's hard for them to run after caribou or rabbit for food because they can't run fast on hard ground because it tears up their skin under their paws," she said. "They're much easier to run on soft snow, so they couldn't get their food, so they had to pack."

James represents Gwich'in Council International and has won the Goldman environmental prize for defending the caribou herd that has sustained her people for 20,000 years. She has no doubt the changes in the north are due to global warming.

Neither did Olav Mathis Eira, a Norwegian reindeer herder and vice president of the Saami Council, which represents the indigenous Saami people of Norway, Sweden, Finland and Russia.

'READ THE ICE'

"We're seeing the same changes in Norway too on the other side of the pole," he said in the same interview. Eira said there was more precipitation and more extreme weather, including thawing and refreezing in winter, which creates layers of ice that make it hard for reindeer to find food.

There are also new "bugs" that manage to survive the winter to attack the reindeer, Eira said.

"They (the reindeer) were infected with a parasite that usually dies during a cold winter, but since the winter was so warm, it survived and infected the reindeers and they found about 70 reindeers that had died of that infection," he said. "That's quite scary."

Megan Alvanna-Stimpfle, who is from Nome, Alaska, and heads the Inuit Circumpolar Youth Council, said the change in climate undermined a supportive culture and may be one cause for suicide among the young.

"There's a high rate of youth suicide in Inuit villages and we think it's correlated to our loss of language and the ability to live healthily in isolated Arctic communities," Stimpfle said in the interview.

The youth council aims to revive Inuit culture, she said, "but it's complicated by the change in the climate, because people are unable to read the ice."

"Reading the ice" means relying on millennia of Inuit observation to determine when and where ice is safe, Stimpfle explained. The changing Arctic climate has undermined that traditional system, and some Inuit have fallen through ice in places where it used to be safe, she said.

But why should the majority of the world's people, who live in temperate or tropical areas, worry about the effects of global warming in the Arctic?