A decade ago most experts would have thought it impossible. But several teams of scientists say the Arctic ice cap had shrunk to its smallest recorded extent, volume and area.
Environmental physicists from the University of Bremen said on September 9 the Arctic ice cap extent was “small as never before”.
The melt had exceeded the previous record low set in 2007 — a year Realclimate.org described as “apocalyptic for Arctic sea ice”.
This year the summer ice cap extent is about 50% smaller than in 1972. It’s likely the Arctic has not had less ice cover for about 8000 years.
As of September 13, scientists at the US National Snow and Ice Data Center (NSIDC) said its data suggested the minimum ice extent was still slightly higher than the 2007 level.
The NSIDC said the discrepancy was because the University of Bremen result was based on higher resolution satellite data that “allows small ice and open water features to be detected that are not observed by other products”.
Despite the different results, the NSIDC said “all of the data agree that Arctic sea ice is continuing its long-term decline”.
The University of Bremen team blamed human-caused climate change for the big melt.
Their September 9 report said: “It seems to be clear that this is a further consequence of the man-made global warming with global consequences.”
They said the Arctic melt cannot be “explained with the natural variability [of the weather] from one year to the next”.
Rather, “climate models show … that the reduction is related to the man-made global warming which, due to the ice albedo effect, is particularly pronounced in the Arctic”.
The “ice albedo effect” refers to how the melting of the ice cap adds to and speeds up the warming process. As the ice cover retreats, the darker open water absorbs more heat from the sun, which in turn melts more ice.
This is why commentators such as Climateprogress.org’s Joseph Romm have described the Arctic melting as a “death spiral”.
If the Arctic melt continues on its current trend, the area could be completely ice-free during summer by the 2030s. At least one scientist, the oceanographer Dr. Wieslaw Maslowski, has predicted the Arctic could be ice-free in summer as early as 2016.
The Arctic melt matters because it dislocates the fragile Arctic ecosystem. The US Center for Biological Diversity said on September 9: “The rapid loss of sea ice poses a severe threat to polar bears, ice seals, walruses and other Arctic animals that rely on the sea ice for survival.”
It said “researchers recently reported that polar bears and their cubs are dying in increasing numbers because they are being forced to swim grueling distances across open water when there is no sea ice to be found.”
But the continued shrinking of the Arctic ice cap will also make dangerous, runaway climate change a dead certainty.
Scientists say the retreat of the Arctic ice cap will cause permanently frozen soils in Siberia and Canada to thaw.
A 2009 study estimated these frozen soils lock away about 1.5 trillion tonnes of greenhouse gases, mostly methane. That’s about double the amount of carbon in the atmosphere today.
The frozen Arctic seabed could be an even bigger source of greenhouse gases. A University of Alaska research team was shocked to find in 2010 vast amounts of methane already leaking from seabed off the East Siberian coast.
Lead researcher Natalia Shakhova said in March that year: “The amount of methane currently coming out of the East Siberian Arctic Shelf is comparable to the amount coming out of the entire world’s oceans.”
The US National Science Foundation said the “release of even a fraction of the methane stored in the shelf could trigger abrupt climate warming”.
The University of Bremen scientists warned that the Arctic sea ice was much thinner than in the past, saying “the total mass of Arctic sea ice decreases even more drastically than the sea ice extent”.
Modelling of the Arctic ice volume by the University of Washington’s Polar Science Center backs up this conclusion.
On September 7, the centre said the Arctic sea ice volume was the lowest on record — and the melt season is not over yet.
Remarkably, the centre’s data suggests the Arctic summer minimum ice has lost about half its volume since 2006 and a third of its volume in the past three years.
The fabled northwest and northeast sea passages, long considered impassable, are again ice-free in summer this year — a fact the Arctic Ice Sea Blog called “the new normal”.
Shipping companies have already leapt to exploit this short cut. In August, the BBC said “Suez-style” tankers had already shipped natural gas from Russia to Asian ports through the northeast passage.
Glaciologists have also been surprised at the rapid retreat of glaciers in north-west Greenland.
Aberystwyth University’s Dr Alun Hubbard told the September 2 Welsh Western Mail that the ice lost from Greenland’s Petermann Glacier over the past two years had “rendered [him] speechless”.
“Although I knew what to expect in terms of ice loss from satellite imagery, I was still completely unprepared for the gob-smacking scale of the break-up,” he said.
“It was just incredible to see. This glacier is huge, 20 kilometres across, 1000 metres high. It’s like looking into the Grand Canyon full of ice and coming back two years later to find it’s full of water.
“It’s quite hard to get your head around the scale of the change.”
Hubbard said the glacier's melt was double what he had expected.
The Arctic death spiral is largely a consequence of the fossil fuel economy. To have any hope of avoiding the worst impacts of climate change, fossil fuels must be phased out and greenhouse gas emissions cut to zero as soon as possible.
But fossil fuel companies are moving in on the Arctic, hoping to exploit the oil and gas reserves made accessible by the retreating ice.
Geologists say the Arctic region might hold up to 160 billion barrels of oil — worth more than US$18 trillion — the September 6 Independent reported.
In late August, oil giant ExxonMobil signed a multi-billion dollar deal with the Russian state-owned oil company OAO Rosneft to exploit Arctic oil fields.
Other oil companies, including Shell, Cairn Energy and BP are rushing to join the Arctic oil rush.
Greenpeace’s Ben Ayliffe told the Independent that an oil spill in the remote and extreme conditions in the Arctic would “make dealing with something like [BP’s Gulf of Mexico] Deepwater Horizon look almost straightforward.”
He said: “Responding to a Gulf of Mexico-style spill off somewhere like Greenland would be impossible.”