By Alex Kirby BBC News Online environment correspondent

Scientists say the average winter temperature in Alaska has risen by 4 Celsius in the last 40 years.

This rate is about 10 times faster than most of the rest of the world.

Many Alaskans say the state itself is partly to blame, because they believe its own oil resources are helping to drive climate change.

They say the ice is melting and the weather warming, with disastrous results.

The claims come in a film made by Television Trust for the Environment (TVE) as part of its Earth Report series.

The film, Baked Alaska, shown on BBC World, says the first effects of climate change are shaking the Arctic ecology, with every barrel of Alaskan oil burned making the problem worse.

 Click here to watch BBC World and its report on Alaska.

The film says the oil industry generates about $50m annually, providing 80% of Alaska's income.

Worried expert

Professor Gunter Weller is director of the Center for Global Change and Arctic System Research at the University of Alaska in Fairbanks. He says the oil revenue has accustomed Alaskans to an excessive lifestyle.

The caribou depend on the Alaskan tundra

He tells TVE: "Unless we do something about the use of fossil fuels, then the climate impacts will become worse and will be a serious problem."

TVE visited one village on Alaska's west coast, Shishmaref, which it describes as "at the sharp end of the Western world's dependence on fossil fuels".

The village is on an island that is about 400 metres (a quarter of a mile) wide. For seven months of the year, it should be locked in by sea-ice stretching all the way to Russia.

But one village elder, Clifford Weyiouanna, tells TVE: "The currents have changed, ice conditions have changed, and the freeze-up of the Chukchi sea has really changed, too.

"Where we used to freeze up in the last part of October, now we don't freeze till around Christmas time.

"That ocean out there should under normal conditions be four feet thick. I went out, and the ocean ice was only one foot thick."

Vicious circle

Over the last 40 years, the villagers estimate, they have lost hundreds of square metres of land. Robert Iyatunguk, co-ordinator of the Shishmaref Erosion Coalition, says the shrinking of the sea-ice is leaving the village more vulnerable to increasingly violent weather.

Polar bear skins make warm moccasins

He tells TVE: "We're in a panic mode because of exactly how much ground we're losing. If our airport gets flooded out, there goes our evacuation by 'plane."

Professor Weller believes Alaska is caught in a self-sustaining cycle of climate change.

He says: "As the climate warms, snow and ice melt. So you have more solar radiation being absorbed. Greater heating in effect melts more snow, and so this positive feedback loop is one of the main features why we have an amplification of the climate in the high latitudes."

Subterranean heat

Most of Alaska is built on permafrost, a layer of frozen ground that has not melted since the last ice age.

But Professor Weller and his colleagues say the permafrost has warmed by about 1.5 C over the last 30 years, causing buildings to collapse in Fairbanks and elsewhere.

Some scientists believe that the climate changes being witnessed today are entirely natural, and that it is therefore pointless to try to reduce any influence humans may have.

And, in any case, they argue there is good evidence that some regional populations of animals - polar bears and bowhead whales, for example - are thriving because of the slightly warmer waters around Alaska.