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NSIDC director: “The volume of ice left in the Arctic likely reached the lowest ever level this month.”

Serreze: “I stand by my previous statements that the Arctic summer sea ice cover is in a death spiral. It’s not going to recover.”

“We are proud of being the first sailing vessel, together with “Peter 1st”, that ever has sailed through both the Northeast and Northwest Passage in one short Arctic summer.”

This amazing Arctic melt season is finally coming to an end. We just about equaled 2008 for the second lowest sea ice extent and area. But volume matters more — and here it looks like we’re setting the record.

We’ve seen that National Snow and Ice Data Center (NSIDC) scientists have tracked a sharp drop in oldest, thickest Arctic sea ice. So it’s no surprise that the Polar Science Center’s PIOMAS model for mid-September shows a record low volume for the month and hence the year and hence “any time in recent geologic history”:

Daily Sea Ice volume anomalies for each day are computed relative to the 1979 to 2009 average for that day. The trend for the 1979- present period is shown in blue. Shaded areas show one and two standard deviations from the trend.

This graph shows more than a 1000 km^3 drop in ice volume over the record low last year of 5,800 km^3 (67% below its 1979 maximum). I did check with PSC about their confidence level in this relative decline.

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They said that they don’t have credible numbers for the uncertainty of the model estimates, so it is possible that this volume drop is within the model error. For them, “The more important point in my view is that 2010 continues a long-term trend of declining sea ice volume.”

NSIDC director Mark Serreze was more direct in an email interview: “The volume of ice left in the Arctic likely reached the lowest ever level this month.”

He was confirming the accuracy of a terrific IPS story, “Arctic Ice in Death Spiral,” by (long-time CP commenter) Stephen Leahy. Serreze explained to Leahy:

“I stand by my previous statements that the Arctic summer sea ice cover is in a death spiral. It’s not going to recover,” he said.

There can be no recovery because tremendous amounts of extra heat are added every summer to the region as more than 2.5 million square kilometres of the Arctic Ocean have been opened up to the heat of the 24-hour summer sun. A warmer Arctic Ocean not only takes much longer to re-freeze, it emits huge volumes of additional heat energy into the atmosphere, disrupting the weather patterns of the northern hemisphere, scientists have now confirmed.

You can see the 5-day moving average for the sea ice extent that NSIDC tracks has continued to decline through yesterday September 21 to nearly 4.5 million square kilometers — far below for predictions of both the disinformers and the experts:

What are the implications?

I’ve reported on the voyage of Thorleif Thorleifsson, captain of the “Northern Passage,” who, with explorer B¸rge Ousland, has been making a “daring attempt to sail through both the Northeast and Northwest passages during one and the same season” (see Captain’s log from the Chukchi Sea: “The water temperature is 7.5 degrees. If we weren’t sailing, it would be a great temperature for a swim!”). Now he and B¸rge report on “Completing the passage”:

Expedition Report, 06.07 CEST:Today, on the 21st of September, we enter Lancaster Sound and reach the 74th parallel, considered by most as the exit (or entrance) to the Northwest Passage. We are proud of being the first sailing vessel, together with “Peter 1st”, that ever has sailed through both the Northeast and Northwest Passage in one short Arctic summer. We congratulate “Peter 1st” with their achievements through the ice….

Our expedition is one of the most environmentally friendly of its kind ever undertaken. We have used sail more than 90 percent of the time; only in between thick drift ice and in and out of harbours have we had some modest help from our small outboard motor.

For the captain and crew of the “Northern Passage” this is not merely a question of a sports achievement — to complete both passages — Thorleif and B¸rge both have a strong environmental commitment, and are particularly concerned with the ongoing climate changes.

It is, unfortunately, the dramatic changes in Arctic sea ice conditions in recent years that have made this trip possible. On the time of Roald Amundsen it took five to six years to complete the same distance, due to the extremely difficult and demanding ice conditions. Now we have proven that it is possible to make the voyage in a 31-foot fibreglass sailing boat, equipped with a 10 horsepower outboard motor for emergencies. This shows how dramatic and how fast these changes are happening. The changes that we are witnessing will influence climate on a global scale, in addition to the whole range of animal life in the Arctic — especially seals and polar bears, whose lives are dependent on the sea ice.

It is our hope that our voyage will be seen as a strong, visible symbol of the scale and the speed of these changes.

That’s one of the local impacts. Leahy talks to leading scientists, who spell out the broader consequences of our inaction:

There is growing evidence of widespread impacts from a warmer Arctic, agreed Serreze. “Trapping all that additional heat has to have impacts and those will grow in the future,” he said.

One local impact underway is a rapid warming of the coastal regions of the Arctic, where average temperatures are now three to five degrees C warmer than they were 30 years ago. If the global average temperature increases from the present 0.8 C to two degrees C, as seems likely, the entire Arctic region will warm at least four to six degrees and possibly eight degrees due to a series of processes and feedbacks called Arctic amplification.

A similar feverish rise in our body temperatures would put us in hospital if it didn’t kill us outright.

“I hate to say it but I think we are committed to a four- to six-degree [Celsius] warmer Arctic,” Serreze said.If the Arctic becomes six degrees warmer, then half of the world’s permafrost will likely thaw, probably to a depth of a few metres, releasing most of the carbon and methane accumulated there over thousands of years, said Vladimir Romanovsky of the University of Alaska in Fairbanks and a world expert on permafrost.

Methane is a global warming gas approximately 25 times more potent than carbon dioxide (CO2).

That would be catastrophic for human civilisation, experts agree. The permafrost region spans 13 million square kilometres of the land in Alaska, Canada, Siberia and parts of Europe and contains at least twice as much carbon as is currently present in the atmosphere — 1,672 gigatonnes of carbon, according a paper published in Nature in 2009. That’s three times more carbon than all of the worlds’ forests contain.

“Permafrost thawing has been observed consistently across the entire region since the 1980s,” Romanovsky said in an interview.

A Canadian study in 2009 documented that the southernmost permafrost limit had retreated 130 kilometres over the past 50 years in Quebec’s James Bay region. At the northern edge, for the first time in a decade, the heat from the Arctic Ocean pushed far inland this summer, Romanovsky said.

There are no good estimates of how much CO2 and methane is being released by the thawing permafrost or by the undersea permafrost that acts as a cap over unknown quantities of methane hydrates (a type of frozen methane) along the Arctic Ocean shelf, he said.

“Methane is always there anywhere you drill through the permafrost,” Romanovsky noted.

Last spring , Romanovsky’s colleagues reported that an estimated eight million tonnes of methane emissions are bubbling to the surface from the shallow East Siberian Arctic shelf every year in what were the first-ever measurements taken there. If just one percent of the Arctic undersea methane reaches the atmosphere, it could quadruple the amount of methane currently in the atmosphere.

Abrupt releases of large amounts of CO2 and methane are certainly possible on a scale of decades, he said. The present relatively slow thaw of the permafrost could rapidly accelerate in a few decades, releasing huge amounts of global warming gases.

Another permafrost expert, Ted Schuur of the University of Florida, has come to the same conclusion. “In a matter of decades we could lose much of the permafrost,” Shuur told IPS.

Those losses are more likely to come rapidly and upfront, he says. In other words, much of the permafrost thaw would happen at the beginning of a massive 50-year meltdown because of rapid feedbacks.

Emissions of CO2 and methane from thawing permafrost are not yet factored into the global climate models and it will be several years before this can be done reasonably well, Shuur said.

“Current mitigation targets are only based on anthropogenic (human) emissions,” he explained.

Present pledges by governments to reduce emissions will still result in a global average temperature increase of 3.5 to 3.9 C by 2100, according to the latest analysis. That would result in an Arctic that’s 10 to 16 degrees C warmer, releasing most of the permafrost carbon and methane and unknown quantities of methane hydrates.

Can’t really argue with that:

If this happens, it doesn’t mean modern human civilization is necessarily doomed to multiple catastrophic climate impacts, but it certainly means that humankind’s effort to reduce emissions and avoid 10°F warming, which I expect will become a desperate global effort sometime in the 2020s, will become increasingly harder, taking up more and more of our resources and know-how.

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