(CP) - Dire predictions expected later this week from the Intergovernmental Panel on Climate Change may in fact be too conservative, according to new Arctic sea ice data.

A U.S. study on northern sea ice found that not only did 2006 have the second-lowest amount of ice on record, but also that the ice is retreating faster than the panel's climate models have predicted.

"The model forecast may be underestimating what we could expect in the future years," Walt Meier, a climatologist with the National Snow and Ice Data Centre in Boulder, Colo., said Wednesday.

Meier's group tracks the annual maximum extent of the Arctic sea ice by the end of the northern winter, which is defined as March 31.

This year, 14.7 million square kilometres of Arctic ocean around the globe was covered by at least 15 per cent ice. That's only a little more than last year's 14.5 million square kilometres, which was the lowest figure ever recorded.

The average from 1979 to 2000 was 15.7 million square kilometres.

"It's basically continuing that trend," said Meier.

But his group also compared their measurements, which were based on observations from satellite images, with predictions generated by climate models developed by the more than 1,000 scientists of the Intergovernmental Panel on Climate Change.

That panel is expected to release a report Friday that details some of the anticipated consequences of climate change. Leaked versions of the report suggest those effects include rising sea levels that could force hundreds of millions of people in low-lying, largely poor nations from their homes.

Comparing the figures from the panel's models with actual measurements going back to the late 1970s revealed a disturbing gap, said Meier.

"What we're seeing, in the summertime particularly, is the (sea ice) that we've observed is actually declining much faster than the models have shown.

"The model forecast . . . may be missing some of the processes that are causing decline, some of the feedback mechanisms that accelerate the decline of the sea ice."

The panel's predictions should be taken as "conservative estimates," Meier said.

Observations by Meier's group show the sea ice decline is universal across the circumpolar world. While small, short-lived increases have been seen in areas such as the Gulf of St. Lawrence, the Canadian Arctic from Baffin Bay to the Beaufort Sea has seen "significant" ice loss.

In fact, satellites spotted a vast area of open water in the Beaufort for six weeks early this past winter. About 50,000 square kilometres - an area roughly the size of Nova Scotia - suddenly emerged ice-free, 200 kilometres inside the ice pack.

"That was very unusual," Meier said. "We've seen occasional small holes in the ice in the summertime, but nothing that lasted that long or near that large."

However, the data doesn't suggest that the Northwest Passage will be able to support international shipping anytime soon. Ice tends to stay locked around the islands of the Canadian archipelago.

"There'll be more frequent years when you'll have less ice in the Northwest Passage and it'll be more navigable," Meier said. "But I don't think you're going to see it go away completely in that region anytime soon.

"You may have some easier shipping into Hudson Bay, but the Northwest Passage is still going to be iffy as far as trying to plan anything. In terms of a practical use, it's going to be a while before it opens up."