In a story that caught the attention of only the more astute climate science journalists a few weeks ago, one of the more experienced oceanographers of our time, Peter Wadhams of Cambridge University, reported that the Arctic ice cap is melting much faster than we thought. How much faster? So fast that the rate made the story seem too alarmist to take seriously.
As MSNBC’s Alex Johnson reported,
Scientists had previously predicted that the summer sea ice would disappear from the Arctic by 2040. But Wadhams’ measurements indicate that the thinning was already approaching 50 percent and that the ice could disappear by 2020.
“What’s happening to the Earth as a whole is a catastrophe, and the disappearance of Arctic sea ice has got to be one of the first indicators of the catastrophic changes,” Wadhams told ITN’s Lawrence McGinty. “It’s something we can see. We can see it from space – the Arctic pack ice is there, it’s white, and soon it won’t be there.”
Sounds bad, but it was the death of two Royal Navy sailors during Wadham’s submarine expedition that attracted more attention that his scientific findings. And what little reporting there was tended to add the usual skeptical observations, such as this one
Walt Meier, a research scientist at the National Snow and Ice Data Center at the University of Colorado, called Wadhams’ 13-year projection “extreme, but not completely implausible,” and cautioned that the thinning could simply be the result of “compression of thicker ice into a smaller region.”
“It’s dangerous to extrapolate into the future, especially from such a short period,” Meier told MSNBC.com on Tuesday. While Wadhams’ estimates “are not totally out of line with possibility,” he added, “my feeling is that estimates of 13 to 20 years for the loss of summer sea ice are overly pessimistic.”
In a slightly ironic twist, however, it was Meier’s own National Snow and Ice Data Center that later helped confirm those overly pessimistic findings, which received much more media attention yesterday and today.
Andrew Revkin’s still cautious and brief report in the New York Times begins with
Climate scientists may have significantly underestimated the power of global warming from human-generated heat-trapping gases to shrink the cap of sea ice floating on the Arctic Ocean, according to a new study of polar trends.
More details, quite alarming in tone, appear in a joint press release from the National Snow and Ice Data Center and National Center for Atmospheric Research and are uncritically reproduced by the Environment New Service:
The study, “Arctic Sea Ice Decline: Faster Than Forecast?” will appear Tuesday in the online edition of Geophysical Research Letters. It was led by Julienne Stroeve of the National Snow and Ice Data Center and funded by the National Science Foundation and by NASA.
Stroeve and her team found that, on average, the models simulated a loss in September ice cover of 2.5 percent per decade from 1953 to 2006. The fastest rate of September retreat in any individual model was 5.4 percent per decade.
But newly available data sets, blending early aircraft and ship reports with more recent satellite measurements that are considered more reliable than the earlier records, show that the September ice actually declined at a rate of about 7.8 percent per decade during the 1953-2006 period.
Doing the math (triple the previously calculated rate), it turns out that the summer north polar ice cap may indeed have only 13 years left.
This is bad news indeed, and not just for polar bears. The resulting decline in the Earth’s albedo (reflectivity) will be significant. And what follows could very well be an accelerating positive feedback loop, in which warmer waters, which absorb more heat thanks to diminishing ice cover, only serve to melt more water, and so on. The effects for northern latitudes, including the thermohaline pump in the North Atlantic, will almost certainly be … dramatic, if not catastrophic. We’re talking about one of those mythical tipping points, here folks.
If subsequent measurements confirm Wadhams and Stroeve’s finding, things are about to get very very interesting.