Are we setting up for a Blue Ocean Event in Sept 2017?
Many climate scientists expect a gradual transition, with ice free not likely for at least a decade or more. Wadhams and a few others expect a phase change, with feedbacks leading to a rapid transition of the Arctic to open ocean much sooner.
Most climate scientists follow Chris Reynold's "Slow Transition" idea.
ktonine at the Arctic Sea Ice Forum offers this summary of it.
Critical to all this is that I am becoming convinced that the approximate levelling of PIOMAS volume over the last few winters is telling us that the pack is becoming dominated by FYI, whose thermodynamic equilibrium thickness is largely setting the peak volume in April. Even if one year, with exceptionally good melt weather, were to lead to extent below 1 million kmsq, this will be unlikely to be repeated, and for the record, I do not think this is likely anyway. To get to a state of near ice free conditions in late summer we will need to see significant thinning of the winter peak thickness, which needs far greater winter warming. I don't think this is likely to be a fast process.
So I do not expect to see a virtually sea ice free state until later in the next decade - at the earliest, I suspect that Overland and Wang may be proven right in pinning it on the 2030s. In terms of expectations amongst many in the amateur sea ice community this is a slow transition. However in geological terms it remains abrupt.
This year we *are* seeing significant thinning in winter thickness, but it still requires an even thinner pack to meet the requirements to get reliably under 1 million kmsq. So, the question still remains: is this winter's lack of FDDs a step change or is it an anomaly?
I've always been an advocate of slightly faster timing than Chris for these processes, but the arctic has always managed to surprise me with it's resilience. And in the end we're realistically talking about a difference of 10 to 15 years -- virtually no difference at all in scientific terms.
What I think we should also remember is that the scientist that first really went out publicly on a limb with an "over-the-top" prediction was Wieslav Maslowski. Back in 2006 Maslowski predicted a nearly ice free arctic in 2016 +/- 3 years. What many don't know is that Maslowski was not talking about sea ice are or extent - but volume. And 'nearly ice free' he defined as losing 80% of the 1979-2000 summer volume (see article by Joe Romm at ThinkProgress). 2012 came close. 2017 should come even closer - perhaps even make that prediction come true. [emphasis mine]
oren offers this caveat about Freezing Degree Days (FDD), which have been drastically lower this season.
Chris R's main assumption was that the freezing season remains mostly the same, with FDDs stable or perhaps undergoing a small decline, and that therefore arctic sea ice cannot just pass a tipping point and disappear following its first ice-free summer. Instead, even if a freak summer came along and melted all the ice, the refrozen arctic would still not necessarily melt out the year after. This is what he dubbed a "slow transition", as opposed to a one-way phase change.
The theory is very strong and Chris at the time gave many good arguments and explanations, but I believe this year has already shown its main flaw, and that is the FDD assumption. FDDs crashed this winter, leading to the possibility of a melt-out with a regular un-freakish summer. [emphasis mine]
So we have two schools of thought, and Freezing Degree Days is the pivot between them.
Amateurs such as Paul Beckwith expected melt-out last year. I can't imagine it will take longer than September 2017 or possibly 2019. Many new behaviors have emerged: jet stream changes, low Arctic pressure where there used to be high pressure, Atlantic storm tracks near or into the Arctic bringing both heat and moisture, stratosphere anomalies, shifts of the Hadley and Polar Cells, and the virtual disappearance of multiyear ice. The appearance of clouds in Spring and Summer the last couple of years helped the ice. This is also novel behavior. Overall I agree with the comparison to hysteresis, a nonlinear system fluctuating back and forth between two states, that often proceeds shifting from a previous stable state to a new one.
Hold on to your hats.
Ice looks bad, but we're still not expecting less than 2012.
tonight's worldview images show just how bad the conditions are on the Atlantic side of the pole . Open water is visible beyond 89'North ! . I do not see a single piece of ice more than 20km in diameter between the pole and Atlantic . Considering the weather the ice is in appalling condition so any potential disturbance will have interesting consequences .
Call it a gut feeling, but I think the the melt season may go deep into September and come closer to the 2012 record than many expect.
While refreeze will soon begin, notable changes have begun in The Arctic Ocean. One such change is evident in the region from the Atlantic Ocean into the Barents Sea, which is called encroaching Atlantification. Basically the halocline is weakened and warmer Atlantic water moving north is penetrating further at intermediate depth. The gif shows the area being Atlantified with a mask.
Source of above gif, and here's some of the discussion:
"Arctic sea-ice loss is a leading indicator of climate change and can be attributed, in large part, to atmospheric forcing. Here, we show that recent ice reductions, weakening of the halocline and shoaling of the intermediate-depth Atlantic Water layer in the eastern Eurasian Basin have increased winter ventilation in the ocean interior, making this region structurally similar to that of the western Eurasian Basin [~Svalbard]."
The associated enhanced release of oceanic heat has reduced winter sea-ice formation at a rate now comparable to losses from atmospheric thermodynamic forcing, thus explaining the recent reduction in sea-ice cover in the eastern Eurasian Basin. This encroaching atlantification of the Eurasian Basin represents an essential step toward a new Arctic climate state, with a substantially greater role for Atlantic inflows.
it also makes sense not to include 'Barents Boundary' ice that lies south of the continental shelf bathymetric break, ice which is probably going to melt regardless of clouds, cool air or low wind. Atlantification hasn't gone away, it's just been smothered (temporarily masked) by ever-incoming ice.
The noteworthy development this summer has been a steady push of ice up against and through this line of islands.
Indeed, the a worse-case scenario for ice loss on the Atlantic side ... could see quite a bit of ice move into the thinning/melting zone over the next month, even as elsewhere the refreeze season had begun (as in in fall 2016). [emphasis mine]
A new study puts the Atlantification of the Eurasian Basin of the Arctic Ocean into long term context.
... both the duration and magnitude of the current decline in sea ice seem to be unprecedented for the past 1,450 years. Enhanced advection of warm Atlantic water to the Arctic seems to be the main factor driving the decline of sea ice extent on multidecadal timescales, and may result from nonlinear feedbacks between sea ice and the Atlantic meridional overturning circulation. These results reinforce the assertion that sea ice is an active component of Arctic climate variability and that the recent decrease in summer Arctic sea ice is consistent with anthropogenically forced warming. [emphasis mine]
A related chart (not in study):
The Polar Ice Caps Have Melted Faster in Last 20 Years than Over At Least the Past 10,000
The 2017 melting season is over.
With a minimum extent of ca. 4.7 million square kilometres, Arctic sea ice continues to retreat
Though slightly larger than last year, the minimum sea ice extent 2017 is average for the past ten years and far below the numbers from 1979 to 2006. The Northeast Passage was traversable for ships without the need for icebreakers.
At the Arctic Sea Ice Forum, jdallen comments:
A fascinating year so far, and one which may possibly reflect a new transitional pattern where feedbacks from increased water vapor like cloud cover and increased snowfall attenuate summer extent loss.
I think this will continue for some time, possibly even decades. I think it will be punctuated at intervals by deeper meltouts to near or under 1M KM2 area, possibly under 1M KM2 extent, but will recover.
I think the transition to fully, seasonally "ice-free" Arctic conditions won't happen until we see water temperatures at depth in the basin rise at least a degree C. At that point, there will be sufficient energy to continue vigorous bottom melt long enough that even the cloud and snow cover feedbacks won't reduce albedo enough to save the ice.
Your might be interested in the relationship of the final ice edge to depth in this gif posted by the A-Team.
Now that the freezing season has begun, air temperatures in the Arctic are once again warmer than average.
Meirion: "If you compare post 2000 Arctic with 1980s and 1990s http://ocean.dmi.dk/arctic/meant80n.uk.php there is a definite trend to warm autumn, winter, spring, cool summer."
Shared Humanity: "Increased atmospheric moisture load, a cloudy Arctic with increased precipitation which previously was a cloudless, if cold, desert. The clouds in the winter block heat from radiating into space. The clouds in the summer, protect the ice from the sun and keep temperatures cool."
At the Arctic Sea Ice Forum, meddoc commented Nov 2nd.
This is also what nullschool Forecasts in 4 days- not uncommon Configuration since 2014 January
The Polar Vortex is virtually split into two Cores above the Last Remaining Bastions of Ice:
Greenland & Siberian Permafrost
Here's today's temperature from earth nullschool:
The pink color in Greenland and Siberia show that those are the two bastions of cold, while the central Arctic basin has only a faint blush.
Ice Shieldz mentions that this sort of polar vortex pattern makes intrusion of warmer moister air into the Arctic more likely. In other words when the Arctic Ocean is warmer than nearby landmasses, the polar vortex is distorted, which causes knock-on effects.
At Arctic Sea Ice Forum, Cid_Yama says:
Another day or two, 2017 will be second lowest [sea ice] for the date behind 2016. It has just now caught 2012. It's going to be another one of THOSE winters in the Arctic.
And Wipneus has just informed us that Fram export has just started up again.
Here's a comparison of this year's Arctic Temperature(red line) to 2016 (blue line). You can see it's not as warm this time, but 2016 was an El Nino year. The grey bell curve is the usual temperature. It looks to me as if a new average curve is forming, significantly warmer than before.