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Doc Snow

Thanks for another excellent summary, late or not!

Doc Snow

And, on a different but related topic, let's not forget that this Friday marks the start of a week of climate action. That's been getting the bulk of my attention for a couple of weeks now, and I commend it to yours, too.

There are actions happening all over the world, starting this Friday, September 20, and continuing until the 27th.

If you are in the US, then you can find an action near you here:


If you aren't in the US, well, there's still probably something near you, and Google is your friend!


Thanks, Kevin!

I didn't have the time to proofread after I finished this update, as I had to run. But all the mistakes have been fixed now, and a final line has been added.

Jim Hunt

An excellent summary Neven.

One thing I've also been wondering about is the 2012 Great Arctic Cyclone. You mention it in passing, but there wasn't one this year. In 2012 it was perhaps in just the right place at just the right time. Not this year though. Is that fact significant do you suppose?

Channelling Doc, on a different but related topic please note that the start of the MOSAiC Expedition is only 4 days away now:


"In September 2019, the German research icebreaker Polarstern will set sail from Tromsø, Norway, to spend a year drifting through the Arctic Ocean – trapped in ice.

In essence Polarstern will be following in the illustrious footsteps of Tara and Fridtjof Nansen's Fram before her, but with vastly more scientists in attendance than previous transpolar drift expeditions."


In my view, the GAC-2012 was indeed there at the right time because of all the melting momentum that preceded it. But even without the GAC, I think 2012 would have finished well below 4 million km2 on the JAXA SIE graph. It's difficult to tell, perhaps it wouldn't have if the weather had been the same as this year, during those final weeks.

James S.

Yes, thank you Neven for the excellent summary! I suspect that GAC-2012 pulled warmer saltier water into the melt equation.

The average data for April 1 and September 1 from JAXA show the climate trend. A simple extrapolation suggests an ice free arctic summer in the 2030/2040 time period.
Years April Sept. delta
1980s 15.2 7.4 7.8
1990s 14.8 6.7 8.1
2000-04 14.6 6.1 8.5
2005-09 13.8 5.3 8.5
2010-14 14.2 5.0 9.2
2015-19 13.6 4.4 9.2

Does anyone have a reasonable idea what may slow this trend?

Jim Hunt

James - Take a look at the "Slow Transition" thread over on the forum:


In essence, the suggestion that once the vast majority of multi-year sea ice has gone the ice in the CAB will still regrow to ~2 meter thickness every winter.

Also the JAXA/ViSHOP extent is now below the magic 4 million mark.

3.99 million km² to be precise!

James S.

Thanks Jim!

I use April 1 and September 1 to avoid influence of weather events near sea ice maxima and minima.

Regrowth makes sense. Are there studies that characterize the factors influencing regrowth? If so, they would be valuable for climate models because their current treatment of sea ice is resulting in conservative predictions compared to observations to date.

Doc Snow

Jim, you wrote:

...once the vast majority of multi-year sea ice has gone the ice in the CAB will still regrow to ~2 meter thickness every winter.

I'm guessing you meant in the current, or rather, a near-future context?

Because should we be sufficiently foolish, I believe there's some evidence that a perennially ice-free Arctic is possible. For instance:

In a further warmed climate, however, we find that a critical threshold associated with the sudden loss of the remaining wintertime-only sea ice cover may be likely.


Doc Snow

Jim scooped me on the news that the JAXA extent has indeed dropped below 4 million--as he says, the 9/16 value stands at 3.99--but perhaps it's worth adding that the corresponding value for 2012, the "champeen", was at the all-time minimum record for JAXA--3.18 million km2.

Can 2019 get any closer before the inevitable happens and its minimum is reached? Once again, it won't take long to see.


And another JAXA drop. Quite an impressive final sprint. 206K dropped in the last 8 days. In the 2005-2019 period only 2005 comes close with 190K dropped in the last 8 days. And 2005 had 1.3 million km2 more ice to melt than 2019!


Should we be freaking out yet?

Jim Hunt

Doc - Possibly the very near future?

Here's an up to date animation of Arctic sea ice age:



Good explanation of the main dynamics of the season.
Looking at PIOMAS anomaly in comparison to recent years, the slope of the graph indicates that relative volume loss started backing off in mid-July. This measure may not be a proxy for melting momentum, but it seems to indicate that something else was going on besides the August slowdown discussed above.

Doc Snow

Neven's comment is on point; this is indeed an "impressive final sprint." From the standpoint of ice conservation, it truly is a 'bitter end' to the melt season.

Specifically, the 9/17/19 number for JAXA came in at 3.96, for a drop of 30k. The ice sure can surprise.

AJT--"Should we be freaking out yet?"

I suppose we should have been freaking out long since. :-(

Jim--thanks for a cool animation (pun unintentional). It's good, albeit very slightly queasy-making! Rather surprising that viewing sea ice at basin-wide scale reminds me, at least, of unset Jello...

Not much old ice left to go, is there? We already knew it, but your animation drives home that point once again.

Doc Snow

And for 9/18, JAXA is up 20k, to 3.98.

Does that mean that 9/17 was the minimum? If you're asking, I appreciate it, given how often I've been wrong throughout this digital vigil I've been doing--but I nevertheless dare to say:

"Based on the date, 9/17 is likely to be the minimum, but not yet certain to be."

Another day or two of decline, and I think we can be pretty darn confident, though.

Doc Snow

And based on the Reanalyzer forecast, I'm thinking we *will* see not "decline" (as I mistakenly wrote for "increase" in my comment above) but rather, well, "increase."

Colder temps and clear skies over some pretty wide areas, it looks like.


After watching the animation it seems clear that we must build a great sea wall to block all that ice flowing out of the Fram strait.


The 2019 melting season thread talks about a decades long transition to a new atmospheric circulation possibly taking place as we speak.
I don't wish to be alarmist and/or misleading but there has been some media alluding to a possible reversal of the vortex around Antarctica, which apparently has only been observed once before in 2002.
Has anyone else heard this about Antarctica? Does it indicate some kind of telecon extinction??

Jim Hunt

AJbT - And the "mod" has just declared that discussion "off topic" over there!

I've also posted an even more off topic "manifesto" of sorts:

"We can be Heroes?"

Is anybody "climate striking"?

Doc Snow

...and JAXA extent is up for 9/19, at 4.01 million km2. Looking like the minimum has come & gone, and will stand at 3.96 on 9/17.

"Is anybody "climate striking"?"


(Running sound for morning event, playing music for an afternoon one. Been organizing my ass off for 3 weeks, when I really couldn't afford to.")

Please attend an event near you. They are happening all around the world; in the US, they can be found via strikewithus.org, and I'm sure outside the US there's something similar.

Make some noise today--how many chances do you think we are going to get?


The bus was 20 minutes late today: apparently because 10 000 kids in Perth held it up!! "Good on 'em!", I told my informative fellow passenger...

Robert S

There appears to have been an extraordinary algae bloom happening north of the Laptev Sea over the past few days. I don't know what this indicates in terms of water temperatures, but given the height of the sun in the sky in that area at this time of year, it's an interesting event.



Are you by any means comparing a crowd of 10,000 kids in Perth to an algae bloom in the Laptev Sea?

Maybe the latter is a "late bloomer", whereas the kids are "early blossomers"?

Or it is the other way around. The "sea" was "born" after the kids.

Cheers P


The kids have done well I say. Go the kids!!


Wipneus posted the mid-month update a few days ago.

Doc Snow

Back, post climate strike--which went pretty well here in Columbia, SC, though with lower participation than I'd like--to say, yeah, the 17th was the minimum, apparently. For JAXA, 3.96 million km2 was it, for 2019.

Of course, the September *monthly* minimum is still in question...

Jim Hunt

Doc - The new PIOMAS numbers are out!

Read all about them, including the September monthly flavour of PIOMAS volume, over at:


Andy Lee Robinson

I prerendered the video up to 2018 and continued when 2019's minimum finally appeared last night... Frames are still rendering, but here's a still to be going on with for now!

Andy Lee Robinson

Finally... here's the latest ice cube video:
Arctic Sea Ice Minimum Volumes 1979-2019

Andy Lee Robinson

#Arctic sea ice volume for Sept in 2nd lowest place ever with an average 4,196 km³.
That's a *quarter* of what it was just 40 years ago at 16,910 km³.
We had hoped 2012 was a fluke, but 2019 reinforces the trend.
#ClimateChange #ClimateCrisis #dataviz #climatebrawl

Jim Hunt

Thanks for the updated "ice cubes" Andy.

Always worth waiting for!

Andy Lee Robinson

Thanks Jim, I can't begin to explain the huge amount of effort that goes into producing the ice cube vid with thousands of lines of code and distributed rendering - this time I had the benefit of a client's 32 core behemoth of a server which did over half the frames on its own.
I just hope I'm able to continue for years to come.

Jim Hunt

Three of the MOSAiC Expedition's Ice Mass Balance buoys are now installed and beaming back data from the high Arctic:


Current sea ice thickness ranges from ~0.2 to ~1.0 meters.

Jim Hunt

The JAXA ViSHOP web site is down at the moment, but according to the University of Bremen’s AMSR2 based extent numbers Arctic sea ice is extent is now once again “lowest for the date” (since their AMSRx satellite records began):


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