When will Arctic Extent dip below 1,000,000 Km^2 (2022 poll)

[The Walrus]

Square kilometers, not miles.

I think 2012 was a freek in terms of just how low it eventually went whilst 2020 was a more true reflection in terms of what extent may look like in a warm summer.

I tend to agree. But the first BOE will be a freak as well, on top of the long term trend.

Most likely.  Even so, 2012 was "only" one million square kilometers lower than 2011 (three-quarters of a million lower than the previous low of 2007).  The bulk of the sea ice would need to decrease significantly still to get close enough for a freak year to create a BOE.  The long term trend will not get there soon.  At this point, it would take a few freak years to get there, which we have not witnessed in a decade.  Perhaps we are due.

[jdallen]

I follow your argument and back in 2007-2010 I would probably have agreed with what you are saying. As an additional argument to what I wrote previously:

April 2017 averaged only 20664 Km^3 and that lower amount should mean more open water formation and albedo feedback so if we are flirting with 20k km^3 melt then on your logic it should have all melted out.

It didn't it ended up rather normal. Were we just incredibly lucky or does this cause you to question your thinking?

Actually, no, it doesn't.  In 2017, melt was only a little above ~16,000km3.

We caught a break. 

If it had been a higher melt year - like 2010, 2012 or 2020, we'd be having a different conversation now.

Recall, I said, not that a melt out *will* happen with typical melt, only that it won't take a 2-sigma year for that to happen.

Is it possible that some locations for volume like Beaufort/Chucki/East Siberian/Laptev are vulnerable and easily melt out while other locations against CAA and central arctic are safer locations? What could cause such a difference in vulnerability? Maybe the movement of ice towards CAA plays a large role in keeping open water formation down in those safe areas while it is promoted in other areas perhaps particularly in Laptev (re the Laptev bite). Open water formation allows albedo feedback to kick in.

I suggest it might be harder to get a BOE than you think.

 

Perhaps; I'm still trying to figure out how to sort through the additional factors that will affect this - I see some discussion down-thread about it (e.g. additional moisture providing more clouds thus affecting albedo, etc.)

The 500lb Gorilla is Atlantification and the increases in system enthalpy over time.  The heat has always been in the system to cause a near melt out, at least over the last 15 years or so with volume crashing.  It just hasn't been accessible because of stratification in the water column, and thus, hasn't made it to the ice.  That heat is moving up the water column, much like blocks being stacked on top of one another, and it appears to be happening fairly fast (glancing at the current state of the Barents and Kara).

The entire system of ice is interdependent.  But specifically, if you knock out seas around the CAB proper, you destabilize the entire system sharpely.  I think that's happening, and increases the system's over all vulnerability accordingly.

Long ago, I predicted a sub 1,000,000 km2 year between 2029 and 2035.  I'm still confident of that, especially with more recent findings that show total climate heat increasing faster than previously anticipated.

[El Cid]

I think your calculations are oversimplified. Low starting value years are harder to melt, so lead to lower melting. There seems to be a correlation between (potential) melt and starting volume.

[Freegrass]

At this point, it would take a few freak years to get there, which we have not witnessed in a decade.  Perhaps we are due.

Looking at the recovery years 2013 and 2014, I doubt very much that it's possible to get 2 or more freak years in a row. The first freak year would release a lot of heat from the ocean and cause the following years to become recovery years. Always happy to be proven wrong of course...

[jdallen]

I think your calculations are oversimplified. Low starting value years are harder to melt, so lead to lower melting. There seems to be a correlation between (potential) melt and starting volume.

Oh, no doubt, you cannot melt ice that isn't there.  There certainly will be an affect there, which I think likely will also be correlated with where the ice is located.  We've discussed for years where we think the last bastion of the ice is located.  To summarize a lot of those discussions, the consensus was that it would be immediately north of the CAA, and possibly tucked in next to Greenland in the Lincoln Sea.

And my calculations aren't over simplified.  To a greater degree they haven't really started.  Beyond simply saying that I think that a 2 sigma melt is no longer required to get to under 1,000,000km2, I'm still forming hypotheses and trying to figure out what numbers to dig into next.

(Edit)
Put more succinctly, the energy for a 19,000km3+ melt already exists in the Arctic.  As the end of season volume declines, it becomes increasingly likely that the energy present will in fact crush the pack.  The devil is in the details of where the ice is located, and whether or not the heat can reach it.  That's where I'm directing my investigations.
Key however here, is what ice is present at the end of the refreeze, which the trend shows categorically is declining at 250km3/year more or less.  It's that starting point which will determine whether or not the pack survives the melt season.  in 6-8 years, I think it will render what happens in the melt season moot.

[crandles]

I follow your argument and back in 2007-2010 I would probably have agreed with what you are saying. As an additional argument to what I wrote previously:

April 2017 averaged only 20664 Km^3 and that lower amount should mean more open water formation and albedo feedback so if we are flirting with 20k km^3 melt then on your logic it should have all melted out.

It didn't it ended up rather normal. Were we just incredibly lucky or does this cause you to question your thinking?

Actually, no, it doesn't.  In 2017, melt was only a little above ~16,000km3.

In case it wasn't clear, by "ended up rather normal", I meant Sept 2017 volume at 4.68 was in the normal range 4.1-5.8 (excluding 2012 low and 2014 high outliers). (So the melt had to be low to achieve this.)

Was that 'caught a break' or is it a systemic problem with your calculations that the remaining ice volume is simply harder to melt out? That might be more than just "you cannot melt ice that isn't there". You talk of 2 sigma events then say "my calculations aren't over simplified.  To a greater degree they haven't really started." Hmm. While I don't really expect to see a sudden reversal of opinion and I am happy to see the concession that location might be important in that last post.

[oren]

Using Neven's words at the time, the Arctic dodged a cannonball in 2017. Weather was very conductive to ice retention. Perhaps the poor 2017 melt was also a result of the 2016 GAC, in the same style of 2013's recovery following 2012's seeming use of the deep heat reserves. But I think it was mostly the luck of random weather.

[jdallen]

<snippage>
Was that 'caught a break' or is it a systemic problem with your calculations that the remaining ice volume is simply harder to melt out? That might be more than just "you cannot melt ice that isn't there". You talk of 2 sigma events then say "my calculations aren't over simplified.  To a greater degree they haven't really started." Hmm. While I don't really expect to see a sudden reversal of opinion and I am happy to see the concession that location might be important in that last post.

I think we're quibbling over language, because I don't really interpret what I said earlier being inconsistent with my most recent reply to you. (Edit)  At what point did I state that location wasn't important for ice retention?  It seems like you are adding meaning to what I said that I did not intend. 

[be cause]

 in 2017 the random weather led to relatively immobile ice , the opposite of this year so far . Fram area export is already well past the 2017 year total and in 2017 there was no volume exported between May and October .
  This year the cannon is already firing furiously . If it continues to be well aimed , the BOE we all await with trepidation will be upon us .

[jdallen]

<snip>
  This year the cannon is already firing furiously . If it continues to be well aimed , the BOE we all await with trepidation will be upon us .

While I agree ice conditions at this point are atrocious and on a par with 2017, I do not think at this juncture we are any more or less likely to see a BOE than we were in 2017.  It is far too early to extrapolate from where we are, and even with a 19,000km3 melt (which would crush 2012's numbers), we still wouldn't get there, especially if the CAB picks up another 2000km3, which it still may.

If there were more ice outside of the CAB and it's adjacent central seas I might think it more probable.  However, checking that possibility, I looked to see if with the increased Fram and Nares export there was a disproportionate amount of ice in the peripheral seas.  There is not.

By extension, as in 2017, thus the outcome hinges solely on the weather, for which the trend won't begin to be revealed until May.