It’s been another lean summer for the Arctic Ocean’s sheath of summer sea ice.
Much of the ice in one region is too thin to survive next summer’s melt season, according to an expedition that trekked across the ice in the Beaufort Sea off the coasts of Canada and Alaska.
An expedition by the World Wildlife Fund and the Catlin Arctic Survey found that the average thickness of the ice it measured was roughly 1.8 meters (6 feet). It released the results today.
After reviewing the data the expedition collected, a team at the University of Cambridge’s Polar Ocean Physics Group concluded that the ice cap is on track to vanish during Arctic summers sometime within a generation.
The new data “supports the consensus view — based on seasonal variation of ice extent and thickness, changes in temperature, winds, and especially ice composition — that the Arctic will be ice-free in the summer within about 20 years.” By “composition” he’s referring to the ratio of thick multi-year ice that resists summer melt to become the foundation for the next winter’s freeze and thinner one- or two-year-old ice that fails to make it through the following summer.
Earlier this month, the National Snow and Ice Data Center in Boulder, Colo., released its end-of-the season wrap-up Oct. 6 and came to essentially the same conclusion.
This year’s summer ice reached the third lowest extent since scientists began tracking the ice with satellites in 1979. But more first-year and second year ice has survived compared with the past couple of summer, notes Mark Meier, a senior scientist at the center.
“If this ice remains in the Arctic through the winter, it will thicken, which gives some hope of stabilizing the ice cover over the next few years,” he said in a statement. “However, the ice is still much younger and thinner than it was in the 1980s, leaving it vulnerable to melt during the summer.”
The center’s director, Mark Serreze, added that “it’s nice to see a little recovery over the past couple years, but there’s no reason to think that we’re headed back to conditions seen back in the 1970s. We still expect to see ice-free summers sometime in the next few decades.”
So where do the latest data leave the matter? Scientists always relish more data. And it’s useful to try to provide ground truth to information satellites gather. But the Catlin-WWF results don’t alter the picture the wider group of polar scientist has been assembling. Global warming continues to take its toll on Arctic sea ice. But natural variability, which plants itself atop the longer-term temperature trends, make precise predictions of an ice-free summer at the top of the world difficult. Hence the “sometime.”
Pete Spotts reports for the Christian Science Monitor.