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.