World Turning its Eyes to the Ice
August 28, 2012
The amount of sea ice in the Arctic has fallen to the lowest level on record, a confirmation of the drastic warming in the region and a likely harbinger of larger changes to come.
Satellites tracking the extent of the sea ice found over the weekend that it covered about 1.58 million square miles, or less than 30 percent of the Arctic Ocean’s surface, scientists said. That is only slightly below the previous record low, set in 2007, but with weeks still to go in the summer melting season, it is clear that the record will be beaten by a wide margin.
According to research by the National Snow and Ice Data Center (NSIDC), based at the University of Colorado at Boulder, the decline in summer Arctic sea ice “is considered a strong signal of long-term climate warming”.
The most recent analysis was partially supported by NASA.
Arctic sea ice fell to 4.10 million square kilometres, some 70,000 square kilometres less than the earlier record charted on September 18, 2007, says the NSIDC.
Scientists say the record was all the more striking as 2007 had near perfect climate patterns for melting ice, but that the weather this year was unremarkable other than a storm in early August.
“I think, unfortunately, this is an example that points more to the worst-case scenario side of things,” says Professor Michael E. Mann, of Penn State University, who was a lead author of a major UN report in 2001 on climate change.
“There are a number of areas where in fact climate change seems to be proceeding faster and with a greater magnitude than what the models predicted.”
The Arctic region is now losing about 155,000 square kilometres (60,000 square miles) of ice annually, the equivalent of a US state every two years, said Walt Meier, a scientist at the National Snow and Ice Data Center.
“It used to be the Arctic ice cover was a kind of big block of ice. It would melt a little bit from the edges but it was pretty solid,” Meier told reporters on a conference call.
“Now it’s like crushed ice,” he said. “At least parts of the Arctic have become like a giant slushie, and that’s a lot easier to melt and melt more quickly.”
Joey Comiso, senior research scientist at Nasa’s Goddard Space Flight Center, said this year’s ice retreat was caused by previous warm years reducing the amount of perennial ice – which is more resistant to melting. It’s created a self-reinforcing trend.
“Unlike 2007, temperatures were not unusually warm in the Arctic this summer. [But] we are losing the thick component of the ice cover,” he said. “And if you lose [that], the ice in the summer becomes very vulnerable.”
Walt Meier, from the National Snow and Ice Data Center that collaborates in the measurements, said: “In the context of what’s happened in the last several years and throughout the satellite record, it’s an indication that the Arctic sea ice cover is fundamentally changing.”
Professor Peter Wadhams, from Cambridge University, told BBC News: “A number of scientists who have actually been working with sea ice measurement had predicted some years ago that the retreat would accelerate and that the summer Arctic would become ice-free by 2015 or 2016.
“I was one of those scientists – and of course bore my share of ridicule for daring to make such an alarmist prediction.”
But Prof Wadhams said the prediction was now coming true, and the ice had become so thin that it would inevitably disappear.
“Measurements from submarines have shown that it has lost at least 40% of its thickness since the 1980s, and if you consider the shrinkage as well it means that the summer ice volume is now only 30% of what it was in the 1980s,” he added.
At this point all we can do is watch, the ice is going to do what its going to do. I’ll try to keep some of the most important graphs posted here and keep up with the most important milestones. For today, what’s stunning to most observers is that we appear to have smashed thru the 4 million square kilometer barrier – The latest value : 3,947,500 km2 according to the Japan Aerospace (JAXA) group. The US NSIDC is somewhere close to that estimate.
I won’t say “get popcorn”, because frankly, I’ve lost my appetite.