MARK COLVIN: Arctic ice may be disappearing at a much higher rate than previously thought.

New research from the US suggests that the Arctic Ocean will be almost ice-free in summer by 2040. Ironically, the ability to sail across the North Pole may open up new shipping lanes for oil tankers.

Barbara Miller reports.

BARBARA MILLER: We've been hearing horror stories on Arctic ice have for some time now, but this latest study suggests crunch point is a lot closer than previously thought.

Mark Serreze from the National Snow and Ice Data Centre in Boulder, Colorado is one of the researchers.

MARK SERREZE: We had always thought that at least in the early stages of climate warming, that the Arctic Sea ice would recover in the autumn. After all, even in a globally warmed world, winter happens in the Arctic.

We'll still have refreeze of that ice. But what we're starting to see is that winter ice is not recovering anymore. What we see in 2006 is this case in point. We see that in the end of November, we have two million square kilometres less ice than we should have in a typical year.

This is telling us that that system is not recovering well anymore.

BARBARA MILLER: Dr Ray Nias is the Conservation Director with WWF Australia. He says the news that what's called the tipping point in Arctic Sea ice may be just a couple of decades away, is alarming.

RAY NIAS: It's already quite clear that polar bears, for example, are struggling enormously to survive even the current changes that are going on.

We could see northern species like all the Arctic wading birds and shorebirds that actually fly to Australia every year on their migration, a huge impact there.

We don't know what it will do to things like whales and seals and the fish populations, but one would presume that very dramatic effects are quite likely there.

BARBARA MILLER: A drastic reduction in Arctic ice isn't bad news for everyone. The opening up of a year round shipping route could be exploited for fishing and further oil and gas exploration.

Professor Will Steffen is Pro Vice-Chancellor of Research at the Australian National University.

WILL STEFFEN: Already, shipping companies in the far north, that is in Canada, Scandinavia, Siberia and so on, are beginning their movements in the springtime earlier than they had 20 or 30 years ago, and that's because of the retreat of the sea ice.

So indeed, it will have economic impacts in terms of increasing the trade across the top of these continents, and even before 2040 or 2060 whenever the ice, whenever it does become ice-free in the summertime.

People will be moving around earlier in the season in that part of the world.

BARBARA MILLER: But for many of the native people who live in the region the further melting of Arctic ice is very worrying indeed.

Professor Amanda Lynch is an Arctic researcher from Monash University. She says if these predictions are borne out they may be unable to survive.

AMANDA LYNCH: They have had to invest quite substantially in modern technology to allow them to safely continue those activities, so that includes GPS locator beacons, rescue helicopters, metal boats with large motors, those kinds of things.

So on one level, you know, I think that they're actually good at adapting even to quite rapid change, but on other levels, there comes a threshold to which they can no longer adapt.

For instance, if we transition to an ice-free Arctic in the summer, that's a level to which they can't adapt because the ecosystems that they rely on can't adapt to those kind of dramatic changes.

MARK COLVIN: Professor Amanda Lynch from Monash University ending that report from Barbara Miller.

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