What a "blue-ocean" event would look like? some possibility this 2018 melting season. Does it look like any of these?
No. The key items to consider are the 2007 and 2012 ice age youtubes. They have been posted here dozens of times. Many people here are overly focused strictly on thermodynamics and single-point summaries of the entire Arctic Ocean, such as a number for area without regards to how that area is distributed. However that distribution is critical to end-of-season.
In those record years (and most others), while thermodynamics plays a decisive role in setting the stage, when extent gets low, winds become the decisive agent via both dispersion of ice to scattered more vulnerable floes, rapid advection to places where the ocean surface water is too warm, and out-of-basin export.
This results in a September picture resembling a comma ","rotated 180º CWwith its tail in the Chukchi and ESS. As with 2018, the lower CAA is the source of this residual ice which was initially about the oldest and thickest left.
Given enough weeks of a quasi-stationary high centered off the Beaufort with an associated westward wind along the Alaskan coast but not a return gyre (a frequent pattern this spring), another 2007 will develop, in conjunction with strong FJL-SV and Fram export.
However pack strength and ice thickness are drastically reduced today relative to 2007 whereas surface water is warmer and freeze-up much later. There's no requirement for another GAC
black gray swan event though one would certainly contribute.
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The whole question of 'first blue ocean' is ill-posed to begin with. It just kicks the climate change can down the road. We should be talking about the knock-on effects of the partially blue ocean already the current reality. No significant effects at 25% ... 50% ... 75% blue ocean?
For example, the Chukchi Sea has open water 11.5 months of the year now. Surely that is way past 'seasonally ice-free'. Who here can remember a meaningful winter ice cover of the Barents Sea? It is actually part of the officially defined Arctic Ocean but now gets thrown in with the Greenland Sea or even North Atlantic.
The discussion on some forums reminds me of one soccer team moving their goal post into the grandstands and even out to the street but the other team somehow not noticing and still playing up to the newly contrived set-up. They'll never score a blue ocean goal because the goal post will then be moved to "twelve months for five consecutive years". After that, thirty years of stats needed to rule out "natural variation". Then more decades to rule out cycles.
Meanwhile we're already in big trouble now from Arctic amplification, with more of it baked in. Whatever the full effects of an altogether missing 'planetary refrigerator' might be, the partial effects of a
diminished planetary refrigerator are already upon us. And that's just the albedo part ... there are many other adverse considerations in the literature.
