All good points philopek, but here is an alternate view:
1) If the 80N+ circle is so much less susceptible to melt then why does that straight line downward trend in ASI volume give such a good fit, with 2019 exactly on target?
https://forum.arctic-sea-ice.net/index.php/topic,119.msg232085.html#msg232085 If the remaining most northerly areas are going to decline at a slower rate then that effect bettter kick in soon, because the straight line September minimum volume trend hits zero in 2032, and the August and October volumes only trail September by a few years. If the 80N+ CAB ice is to be a long term survivor, I would expect that straight line trend to be bending upward by now. But so far at least, the data do not indicate a rate change in volume decline.
Similarly, there is no apparent rate change to justify other than a continued straight line trend in the September monthly
average volume as charted by Jim Hunt
https://forum.arctic-sea-ice.net/index.php/topic,119.msg232040.html#msg2320402) Yes, water temperatures are lower in the icey CAB vs. peripheral seas, but those peripheral sea water temperature anomalies are large and encroaching at an unprecedented rate (as far as I know), e.g.
https://forum.arctic-sea-ice.net/index.php/topic,2888.msg232462.html#msg232462 And with declines in ice coverage of the peripheral seas, the effect of albedo decline to warm surface water during the brief summer edges ever closer to the North Pole.
3) Observations of jet stream weakening and unusual if not freakish warm fronts crossing the North Pole do not bode well for the future of Arctic thermal isolation. I confess to not understanding the details of Sark's analysis, e.g.
https://forum.arctic-sea-ice.net/index.php/topic,2692.msg232323.html#msg232323 but his scenario seems include loss of Arctic thermal isolation, and thus even greater polar amplification of warming. Altered, equable weather patterns could also lead to increased ocean heat transport into the Arctic, which seems to already be happening. What I understand better is the analysis of Jennifer Francis et al. that Arctic air spillage over my head in eastern North America appears to be increasing. Which bolsters Sark's view in that if cold air is spilling out of the Arctic, then warmer air from the south must be migrating in to take its place.
And the Arctic is of course part of the bigger picture. CO2 & CH4 and other GHG emissions, levels in the atmosphere, and surface warming all continue to increase at essentially the RCP8.5 trajectory. If the global system temperature was static, then the factors working against melt at 80+N might show up in the ice volume data. But the global heat reservoir continues to increase, and at an increasing rate. And the vast majority of that heat ends up in the ocean surface layer, where it can be carried to the high Arctic.
4) As for average ice age, the Wipneus images at
https://forum.arctic-sea-ice.net/index.php/topic,119.msg232086.html#msg232086https://forum.arctic-sea-ice.net/index.php/topic,119.msg232040.html#msg232040 show that the CAB ice fortress isn't what it used to be, i.e. it is no longer composed of thick, melt-resistant multi-year ice. I suspect that the reduction of ice quality and "communal integrity" does not get enough attention. That may be the factor that tips the balance to overcome lesser insolation at the North Pole.
So contrary to a long asymptotic stabilization, I can see just the opposite happening -- an accelerated chaotic ASI system breakdown. With thinner fractured fresher ice replacing the previous thicker saltier MYI, loss of the Beaufort gyre nursery to replace MYI, currents and wind patterns to which the CAB was previously resistant may be able to cause accelerated CAB pack rotation. That increased mobility could greatly accelerate export to lower latitude melt zones or out of the Arctic entirely through the Fram Strait. And now the Nares may be a smaller secondary doorway that also allows greater ice pack mobility. Continued Arctic albedo decline moving northward. Warm humid air fronts reaching the NP. Continued Atlantification and Pacification of the Arctic Ocean with escalated SST moving closer to the NP.
If this view of the situation is correct, then we could be close to a systemic breakdown of the ASI, or at least a continuation of current trend despite higher latitude for the remaining ice. We may get insight soon enough - if the the straight-line trend continues, that suggests that the 2012 minimum Sept. volume record has a > 50% chance of being superseded in the next two years.
There are people much smarter than me who study this for entire careers and their understanding as shown in the IPCC reports etc. does not call for such radical change in the next 13 years. With my superficial understanding, I don't hold too much faith in my own opinion. I may be spinning a few facts into conceptual storytelling. I really would love to be wrong.
But I keep coming back to that linear ASI volume graph. Until I see that trend change, my gut says trust the observations.