A pioneering expedition to the north pole has confirmed that Arctic ice is thinner than expected, highlighting fears that the region could be free of ice in the summertime within a few decades.
The Catlin Arctic Survey, led by polar explorer Pen Hadow, found that the area covered by their survey was covered almost entirely by ice less than one year old. The region, in the northern part of the Beaufort sea, used to contain older, thicker ice that formed over several years, and is more resistant to summertime melting.
The survey, carried out earlier this year to increase understanding of the impact of climate change in the Arctic, was beset with technical difficulties and ended with the three explorers being plucked from the ice 300 miles short of the pole, their original destination.
Peter Wadhams of the Polar Ocean Physics Group at the University of Cambridge, who analysed the team's findings, said: "With a larger part of the region now first year ice, it is clearly more vulnerable. The area is now more likely to become open water each summer, bringing forward the potential date when the summer ice will be completely gone."
The average thickness of the ice floes measured by the team was 1.8m, a depth considered too thin to survive the next summer's ice melt season. The team's data has not yet been published, but will be submitted to the journal Cold Regions Science and Technology.
Announcing the findings at a press conference yesterday, Hadow said: "This is the kind of scientific work we always wanted to support, by getting to places in the Arctic which are otherwise nearly impossible to reach for research purposes. It's what modern exploration should be doing."
Problems with a radar designed to scan the ice meant the explorers were forced to make several thousand measurements of ice thickness using a handheld drill along their 300 mile route.
Wadhams said the results agreed with other studies of the region, but that the thinning could not simply be blamed on global warming. Recent changes in wind patterns in the Arctic have also contributed, he said, because it has redirected much of the floating ice.
A Nasa study this summer showed that the Arctic's permanent blanket of ice around the North Pole has thinned by more than 40% since 2004.
While dramatic reductions in Arctic sea ice have fuelled concern about global warming and led to more dire predictions about how soon the ice could disappear, the issue has provoked controversy among scientists.
Earlier this year, Vicky Pope, head of climate change advice at the Met Office said "apocalyptic predictions" about the course of global warming could mislead the public. She said there was little evidence to support claims that Arctic ice has reached a tipping point and could disappear within a decade or so, as some reports have suggested. "The record-breaking losses in the past couple of years could easily be due to natural fluctuations in the weather, with summer ice increasing again over the next few years," she said.