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Gas Glo

>"Once Sea Ice passes through Fram Strait, it's fate is basically sealed"

And if the pips forecast from 10/10/10 for 11th is typical then a lot of (the small remaining amount of) old ice will be lost!

JackTaylor

missed the prelim IJIS SIE for Oct 8

10,08,2010,6165625 = prelim

The excitement and rush is gone, eh?
Me, I'm just getting older and forgetful, "sleeping in" nah - no way.

Looking at my file, again I missed another one, SEP 27

JackTaylor

"thermohaline circulation" Atlantic - Arctic Overturning Current

Artful Dodger | October 10, 2010 at 02:01

"I remember Charles Wilson's discussion
about the possibility of the Atlantic Overturning Current
(a thermohaline circulation between Arctic<=>Atlantic).
If this were ever to grind to a halt... Well Howdy!"

- - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Will it grind to a halt or simply slow down?

A good subject to start some controversy among us. PRO vs. CON

I will take the "CON" as a starter.

IF ARCTIC ICE as it ages, salt "leeches" out becoming less saline
and with the very reduced amount of aged (multi-year-ice MYI) to melt
with most of the remaining ice being new and having more salinity
and melts could this balance the increased fresh-water flow from the
melting glaciers of Greenland.

I believe as the Arctic has changed the Atlantic
(Meridional Overturning Current MOC) has slowed and may become slower
and cause more severe (colder) winters in Northern Europe, until the
world wide circulation finds a new equilibrium
http://oceanlink.island.net/ONews/ONews7/changing_currents.html

But, not enough happening fast enough to cause a complete halt.

Somebody take the PRO it will grind to a halt.

Artful Dodger

Jack: Prelim IJIS SIE for Sep 27, 2010 was 5,322,188 km^2

Can someone post the prelim for Oct 9?

JackTaylor

Lodger, the prelim for 10,09,2010,6268750

Maybe between a few of us we will capture all the prelim numbers.

I don't know yet what I will do with all of them, except for next year during the latter part of the melt season planning a comparison chart, about six weeks, middle of August through the end of September.

My numbers beginning with 01-AUG-2010 are at
http://webpages.charter.net/swf-test/gimg/IJIS-csv-201009.txt

Clare

Thankyou for continuing your informative discussions on here, I feared I would have AIW = 'arctic ice withdrawl' if Neven hiberated this blog completely for the winter.
This link is an aside to The Thread, but seems relevant here as a view from the groundlevel,
(cf. the wonderful satellite images above - how can I translate those into my textile art is a challenge?!)
alluding to the complexity of the issues facing Greenlanders, and a contrast to the excitement & optimism many there will have about the opportunities the oil exploration will bring to their communities:
http://www.nzherald.co.nz/climate-change/news/article.cfm?c_id=26&objectid=10679281
Clare

Neven

So people are exchanging their IJIS prelim numbers here, eh? Not in my wildest dreams did I imagine this blog becoming so useful. :-B
.
Thanks, Clare!
.
cf. the wonderful satellite images above - how can I translate those into my textile art is a challenge
.
How about a collage?

adelady

I must echo Clare's thanks. This is a haven of sanity if not peace of mind.

As for textiles. I'm a knitter so I can see how I might represent some of those ice images. Not sure about the artistic merit though. I've not got a single creative bone in my body.

Neven

PIPS is showing more promise of ice transport:

This should show up in Jack's animation above (like the 10-10-10 BTW, Jack).

adelady

Rats, you beat me to it.

Peter Ellis

Does any graph / Photoshop guru feel up to taking the graph from Maslowski's famous "2016 +/- 3 years" prediction and adding in the published September volume estimates from PIOMAS?

Maslowski:
http://climateprogress.org/wp-content/uploads/2010/06/Maslowski-SMALL.gif or
http://soa.arcus.org/sites/soa.arcus.org/files/sessions/1-1-advances-understanding-arctic-system-components/pdf/1-1-7-maslowski-wieslaw.pdf (page 12)

PIOMAS:
http://psc.apl.washington.edu/ArcticSeaiceVolume/images/PIOMAS_daily_mean.png (seasonal cycle)

http://psc.apl.washington.edu/ArcticSeaiceVolume/images/BPIOMASIceVolumeAnomalyCurrent.png (daily anomaly)

My best guess from eyeballing it is that we're between the red and blue lines: i.e. a complete melt-out between 2013 and 2016.

Artful Dodger

Russian scientists have established Drift Station SP-38 on an ice floe at 76.05 N, 175.34 W in the Chukchi Sea . The plan is to occupy it for a year as it follows the Transpolar drift.

http://en.rian.ru/arctic_diary/20101011/160915578.html

Peter Ellis

The reason I'd like to see an updated version of that graph is that it's the one Maslowski used when he made his famous "Ice Free in 2013" prediction, which the skeptics are happily pointing and laughing at. There's just three problems with their laughter:

1) The prediction was based on volume, not extent: specifically it was for a loss of more than 80% of the summer ice volume relative to the 1979-2009 average of 20,000 km^3.

2) The prediction was for 2016 +/- 3 years, so it can't be falsified till the end of 2019.

3) It may already have come true.

Yes, you read that last one correctly. PIOMAS gives ~13.5 km^3 as the average September volume, and the September anomaly this year was around -9.5 km^3. That leaves 4,000 km^3, which is an 80% loss from a starting value of 20,000 km^3.

Anyone able to make a mashup of the graph + figures and check this out? It's probably worthy of a blog post in its own right if true.

Lord Soth

The average september value is 13,400 km^3 according to PIOMAS, so we are at a 70% loss not a 80% loss; but we are almost there.

Once quick question; if anybody was monitoring the 79N NE Greenland Glacier, there has a huge area of Sea Ice attached to this Glacier. This broke up in early September, but there are one isolated section left. It appears that it is not attached to anything, no islands embed; but it refuses to move south, despite the large amount of transport out of fran strait.

The only thing I can think of, is that this ice is grounded in extremely shallow water, but I find this unlikely for such a large area.

You can see this as the last large chunk in the top right of this image.

http://rapidfire.sci.gsfc.nasa.gov/subsets/?subset=Arctic_r02c03.2010276.terra.1km

Phil263

Peter
There is something that I can get really get my mind around.

If the average sea ice volume for Sept is 20,000 km^3 ( average 1979- 2009) and the anomaly is 9,500 km^3, then the estimated volume for this year should be 20,000 km^3 - 9.500 km^3 = 10,500 km^3 . Where does this 13,500 km^3 come from?
Remember I am a newby!
Then, if the volume is 4,000 km^3 and the minimum ice extent was 4,800,000 km^2, that gives an average thickness of 83 cm ... Is it possible that the leftover pack ice at the minimum would be less than 1 m thick on average?

Kevin McKinney

Phil--

It's always a bit dangerous to answer for someone else, but I'll give it a go--we're among friends, right?

Peter's first linked PIOMAS graph gives the average value for monthly volume over the baseline period. For September, that average value appears to be around 13.5 k--so that's where your questioned value comes from.

My question would be why the baseline for the prediction would be 20 k (the average yearly volume) rather than 13.5 k (the average September value)? If that's what Dr. Maslowski did, then OK; but I'd naively have expected the 80% loss to be from the minimum, not the annual average. (After all, the annual cycle gives you "54% loss" before you even start with long-term melt, if you define it that way!)

As LS points out, baselined from 13.5 k, a 9.5 k negative anomaly is about 70% loss, so Maslowski's prediction doesn't look so impossible.

Peter Ellis

@Phil123: Sorry, I had a typo in my second post. At least part of the issue is that there are two different baseline figures being used.

The figure of 20,000 km^3 is the average summer volume for 1979 through 2000. Maslowski predicts an 80% loss of that by 2016 +/- 3 years according to Joe Romm at Climateprogress.
http://climateprogress.org/2010/06/06/arctic-death-spiral-maslowski-ice-free-arctic-watts-goddard-wattsupwiththat/

The figure of 13.5km^3 is from the first PIOMAS graph I linked, which shows the average yearly cycle for 1979 through 2009. The September figure is around the 13.5km^3 mark - hard to read exactly. Since this baseline now includes the later dates (2001-2009 inclusive), it's considerably lower than 20km^3.


That doesn't seem to be the only difference though. If it was just down to the differing baseline, then the average PIOMAS summer anomaly for the 1979-2000 period should be equal to the difference in the baselines, i.e. around +6.5 km^3. Looking at the second graph I linked, that doesn't seem quite right, it's closer to +2.5 - 3km^3 anomaly on average for this period.

It may be that the figure of 20,000 km^3 was an average across the whole summer, rather than the annual minimum. Or maybe the real figure was 17 km^3 and he just rounded it to one significant figure when talking to Climateprogress. Can't really tell without digging closer into the data

That's why I'd like to see the PIOMAS figures put onto the graph from the Maslowski report!

http://soa.arcus.org/sites/soa.arcus.org/files/sessions/1-1-advances-understanding-arctic-system-components/pdf/1-1-7-maslowski-wieslaw.pdf

Don't know if we have the resolution to properly re-create the entire time series from the PIOMAS anomaly graph, but I guess we could get March/June/September/December values.

fredt34

Previous Russian Drifting Station SP37 was setup in Sept 9, 2009, on a 12x13 km ice floe, 3 m thick. They had to abandon it on june 7, 2010, because of the too important melt - see http://english.ruvr.ru/2010/06/05/9175021.html (it was setup for 2 years). NP37 data could be watched on http://www.aari.nw.ru/resources/d0014/np37/default.asp?lang=0

This years's ice is smaller, and is thinner (2 to 2.5 meters) - and it's "the best they've found"... As the chances to reach the summer are low, I guess that they will develop their artificial platform sooner than expected.

Artful Dodger

Busy this Advection Season, wot? ;^)

Lord Soth: I suspect the fastice attached to the NE Cape of Greenland is protected by a lee-side eddy current. The Shelf extends about 100 km into Fram Strait in this area. Here is a Bathymetric map.

Peter: Several observations after Extending the Maslowski Volume Trend graph:

  • The point of Origin for the linear volume trend is Jan 1995
  • The figure 20,000 km^2 is the Sep min Sea Ice volume for Sep 1994
  • This is roughly when a steady downward trend begins (+/- 2 yrs?)
  • Interesting, Blue data plots are not Sep minimums, maybe Nov??
  • Linear trend passes 80% loss in Sep 2011 (3,900 km^3 is trend target)
  • Zero remaining Arctic Sea Ice by Sep 2014 along linear trend
  • What happens if we extend the trend line beyond Zero Sep Volume?
  • Zero March Sea Ice occurs in another 9.5 years (the peak of annual Sea Ice Volume 'sine wave' remains below 0)
  • This implies a perennially Sea Ice Free Arctic as soon as March 2025
  • If this were to occur, we should expect dramatic increases in salinity, SSTs and the depth of the Surface Layer over the years 2014-2025 as the Atlantic mixes with the Arctic
  • All of this assumes a Linear trend holds. If the underlying trend is in fact exponential, then these targets could be reached even sooner
  • This would be the case if accelerating positive feedbacks take hold.

Phil263: Average Sea Ice thickness computations should use 'Area' rather than 'Extent' for obvious reasons (this topic has been covered on this blog previously). You can use either IJIS or CT numbers to get a feel for the possible range of the Mean (this is after all an estimate; Ron Kwok estimates there is also about 20% uncertainty in the PIOMAS Volume number).

Werther

Lord Soth – The strange pattern of landfast ice break-up on the nort-east Greenland coast interested me too. North of the big ice island you point to was the july break-up of a Corsica-scale part. But this one just held on, with its nose sticking out into the east Greenland stream.
On G Earth I found the name Northwind Shoal in that position. Grazing through the web I stumbled on this link.
http://www.bodc.ac.uk/projects/uk/aui/cruise_programme/documents/jcr106.pdf
Autosub under Arctic Sea Ice (2000)
Among other sites deep keels of Fade Isblink tabular bergs were mentioned, grounded in 80-100 m deep water. It seems to be late ice-age glacier bed and the morphology is still very complicated out there.
I guess Lodger is right, the morphology might cause protective eddies. Some embedded old bergs may still reach the sea bed.
It shows us how interesting the details in the process are, and how some isolated older ice may remain when the virtually ice free summer arrives…

Neven

This would be the case if accelerating positive feedbacks take hold

But there were surely be some negative feedbacks to compensate. Don't ask me why, for I am ignorant.

Artful Dodger

Well, certainly we saw such a negative feedback this Summer were the unusally large amount of open water within the main pack (up to 40% open water by CAPIE) lead to persistent overcast skies. The net effect was still positive, as September's record loss of Extent showed. These are what we call the unknown 'unknowns', but some may bite the neck rather than the heels.

Neven

Well, certainly we saw such a negative feedback this Summer were the unusally large amount of open water within the main pack (up to 40% open water by CAPIE) lead to persistent overcast skies.

But how exactly, my dear Lodger? The holes started showing up for real a long time after the Dipole Anomaly had suddenly vanished. Or do you mean the DA went poof, the ice pack spread out, holes increasingly appeared and this prolonged the domination of low pressure areas, with the highs all the while burning Moscow?

Phil263

Lodger:
Zero March Sea Ice occurs in another 9.5 years (the peak of annual Sea Ice Volume 'sine wave' remains below 0)

This implies a perennially Sea Ice Free Arctic as soon as March 2025

Excuse my incredulity, but can we really expect to see a perennially ice free arctic in the near future? Temperatures at the pole currently average -25C in winter, even if we factor in a large increase in temperature ( say + 10C) that would still put the average far below freezing point!
With regard to the average thickness, I understand your point: we should be using SIA not SIE . If we assume a volume of 4000km^3 and a minimum SIA of 3 m km^2 (CT) that gives a average thickness of 1.3 metres. Does that sound that be right ? I do not know

Artful Dodger

Yes.

Artful Dodger

Phil263: Why do you choose the Pole as your comparison point for avg winter temperatures? Wouldn't it be more accurate to choose an ice free region to compare temps? Remember, there also is zero solar insolation in the Chukchi Sea in January, where the air temp was +4C in early Jan with Ice free seas.

There IS precedent for a perennially sea ice free Arctic during the PETM, it's just a question of how rapid the transition would be from a seasonally ice free state. In this state, the Central Basin would be free of sea ice, have Salinity matching the Atlantic, and higher SSTs due to 24 hour Summer insolation. Then, a better question might be to explain how such a large mass of water could cool to below -1.8C in just 3 or 4 months.

Surely in places like the Canadian Archipelago, there could be local freezing, but this is largely irrelevant. It's the Central Basin that matters, which responds to the laws of thermodynamics, not Human belief systems or timetables.

The future will almost certainly be worse than we think. Since most scientific predictions are made at the 95% confidence level, there is only a 5% change that future changes will be less than predicted.

Two additional possibilities are suggested by the Maslowski Trend line:
1. 1994 was the tipping point for Arctic Sea Ice
2. There is an approx. 30 year lag time between cause and effect.

Exploring the consequences of these (and others) shows why people react by either 1. sticking head firmly in sand (Denial), or 2. become deeply Angry (eco-terrorists). If you've followed this far, you can guess the next three stages are 3. Bargaining (geo-engineering), 4. Depression (climate chaos), and 5. Acceptance (for survivors).

I honestly don't know. Can humankind organize a response to Climate change before all this comes to pass? What do you think?

Neven

Can humankind organize a response to Climate change before all this comes to pass?

I for one don't think it can, so let's hope you're wrong.

Then, a better question might be to explain how such a large mass of water could cool to below -1.8C in just 3 or 4 months.

Yes, that not far-fetched, but so fast? I don't want to think about that. I'm going over to WUWT. They are posting articles from last year to see if anyone notices.

me.yahoo.com/a/Xs1LkmQn0_XQko.cH1qfXW.Bvo0cvQ--

Re Gas Glo and Intrade. Thanks. No, I was not aware Intrade did a market on sea ice. Following the information you posted, I did a little research and Intrade seems to be the most mentioned, even if it isn't running a current bet. It isn't Ladbrokes or William Hill in terms of public acceptance but it is a place to start.

me.yahoo.com/a/Xs1LkmQn0_XQko.cH1qfXW.Bvo0cvQ--

"Can Humankind organize a response?" China, maybe. I don't see anyone else with the political unity. The only way this will be done in the US is when the profit motive is linked to the problem. But the only profit motive would be government funding... and I don't see that happening with the current deficit and politics. Unfortunately, by harnessing the power of gullible and ignorant, the Tea Party has created a monster. Good people individually perhaps but not the ones you want solving a complicated problem.

But more to the point, what would the solutions be? CO2 plans like algae in ponds in the desert would take too long to turn things around. A big reflective mylar sunscreen? Aside from orbital mechanics, the force of light would mean some sort of dynamic position system (no?, obviously I have no clue what I am talking about), cloud manipulation, artificial trees, etc.. And how would the solution be implemented politically? Anyone spent any time thinking about this?

Phil263

There IS precedent for a perennially sea ice free Arctic during the PETM, it's just a question of how rapid the transition would be from a seasonally ice free state.
Lodger, I am not saying that a permanently ice free arctic is an impossibility. But even during the PETM when temperatures increased over a short (geological) time, it took 20,000 years to get to that stage ... 20,000 years ago the pyramids were not even thought of ! I am all for taking into consideration the welfare of future generations, but 20,000 years is really a long way ahead of us.
IMO something will get us before then: we will run out of fossil fuels, minerals, we will run out of food,water; Australia and the US mid west will be desertified ... But Gwynne Dyer in "Climate Wars" seems to think that the worse enemy of mankind is man itself. When confronted with the imminent threat of natural disasters, human societies in an attempt to save themselves will turn on each other. If you look in the past, the imminent cause of the collapse of societies like Easter Island or the ancient Maya was warfare, even though the underlying long-term causes were probably environmental factors ( see Jared Diamond :" Collapse")

Neven

it took 20,000 years to get to that stage

Lodger is talking about sea ice, not about global ice sheets.

But more to the point, what would the solutions be?

Here is an idea for geo-engineering in the Arctic I saw at Michael Tobis' blog. I might do a blog post on that in the future.

Phil263

Interesting piece but it doesn't say what the solution IS ? Is this about setting up a "small scale" reservation where current arctic ice conditions would be preserved? or does Dr Field have a solution to stop the melting of arctic ice altogether? A small scale solution is better than nothing as it will help preserve habitat and species that will be able to recover once conditions have returned to "normal"

As for our Global problems there IS a solution and we all know what that solution is. Slow down economic growth, accept that we live in a finite world and that we have met our limits. If we are clever, we can still manage to preserve some of our lifestyle (in the West) , but first we need to:
1. Stabilise human population and in due course decrease that population
2. Share our resources wiith parts of the world that are still trying to get out of their miserable way of life
3. Use engineering and technology to minimise our footprint on planet Earth rather than to try to get new stuff.

Kevin McKinney

Yes, that was a strange thing about that page! By Googling around a bit, I found another site that said the method Dr. Field proposes--described, by the way, as still being in "stealth mode," which seems about right--involves some kind of reflective shield to be deployed over wide areas of Arctic ice to protect it, and/or keep albedo up should it melt.

How this can economically be accomplished, I haven't the faintest idea. It did inspire me, though, to look again at GRT, the company that is developing CO2 air capture "artificial trees." It's hard to imagine their approach being "the solution," but then again I don't believe in silver bullets for the AGW crisis. What I like about them is that they have what looks like a potentially workable business plan: Phase I has them selling the CO2 for use in carbonated drinks! It then moves on to supplying CO2 for oil extraction, which would sequester the CO2 pretty effectively, based on current data--though it unfortunately also increases oil supply.

Anyway, Google GRT. They have a working model, and are trying to do a commercial prototype.

Artful Dodger

Don't expect too much from Ice911 Research Corporation's Albedo enhancement technology. As Keven says, they're testing a white covering over freshwater lake ice. This wholly fails to address the underlying cause of loss of Arctic Sea Ice: warm water inflows. If they were doing their test in a river, it might be worth the money they're asking for in Charitable donations. We are 500 years away from competence in Geoengineering.

Phil, I'd add a point 4). Find a way to stop Corporations from profiting from the misery of others. Ethics are the only part of a living human being not endowed to the legal entity.

Phil263

Lodger: Totally agree with you on Point 4.

me.yahoo.com/a/Xs1LkmQn0_XQko.cH1qfXW.Bvo0cvQ--

i'm glad people replied. I thought after I posted it that it sounded a bit lazy, certainly a quick search on Bing would have resulted in a lot of, um, results. But I enjoy this site a lot aside a lot and was really only hoping to start a conversation.

My take on evil corporations, etc. is that they will always exist. I remember bartending to pay for college and there was never any chance of the bar creating a control system that couldn't be scammed. Never! Some, admittedly required cooperation and skill to get around. However, the most effective was system that allowed the bartender to 'cheat' a little on his own. Th tacit understanding was that if you were making good money, you didn't want to risk being fired by being too greedy. This is the principle that governs our society today.

Consider from the physical problems involved in getting a pint of beer to you at exactly the moment you want it from the point of view of system design. the knowledge of how to create a beer must exist. All the biological materials must be planted, protected and gathered. The physical materials for guiding the biological conversion from raw materials must be gather, shaped and protected. The process of conversion to beer must be monitored. The final product must be transported and maintained in space and time so that when you say "' 'ello 'arry, two pints and a packet of crisps" that results in a positive response.

Multiplied by billions, if not trillions, this is out networked society. It is a gigantic machine and change has to be an orderly process or that machine will destroy itself. Granted that global warming will destroy people anyway, but that is an outside force. Willing destruction won't happen.

Combine the need for this huge product distribution system with people who want to scam the system from within results in the fact that social stability requires paying the bartender.. so to speak. So, the conclusion is only that the tools available for worldwide change are limited and 'in system' changes. Hope this makes sense, I am a bit rushed.

All those evil corporations are part of the system of information gathering and product distribution.

me.yahoo.com/a/Xs1LkmQn0_XQko.cH1qfXW.Bvo0cvQ--

Wow, sorry about that last post. I was going somewhere, really, but my boss walked in and I panicked and hit 'post' without editing or rereading it. All I was really trying to say is that in regards to Point 4, mentioned above, is that it has to be a bottom up solution, top down won't work. Or so I believe.

Kevin McKinney

". . . a gigantic machine. . ."

Yes. And if it stops. . .

That's part of what appeals to me about the GRT folks; they are working--or trying to--with the dynamics of the system as it is, trying to bootstrap a change.

As I said, they probably won't be "the solution," but their efforts are novel, instructive, and may well make a positive contribution in the end. I'd love to know about some other projects that provide some similar glimmers of hope. Anybody?

JackTaylor

Solutions ! ! !
" the coal industry is proposing that the United States switch from a dirty (oil) to an even dirtier (liquid coal) energy source -- and the industry wants to subsidize it with your tax dollars."
http://www.foe.org/liquid-coal-impending-environmental-disaster

How far backwards will the thirst for gasoline (petrol) take us ???
JackT

Phil263

It seems that a strong La Nina has is now firmly entrenched. We are clearly feeling its effects in Eastern Australia right now ( very wet and cooler than usual) and the prediction is that La Nina will last until March 2011 if not beyond. The last time we had such a strong La Nina was in 1999/2000 ( we had a moderate La Nina in 2007/8 but nothing like this one).
I was wondering what effects if any a strong La Nina would have on :
1- The growth of arctic ice this winter
2- the 2011 melting season.

I could not find any records of SIEs going back to 1999/2000 ( IJIS and UniBremen only go back to 2002). I had a look at the SIA numbers on CT but it is hard to detect anything as SIA back then SIA was higher than now. Does anybody have an idea about this?

Gas Glo

NSIDC monthly averages would surely do.
ftp://sidads.colorado.edu/DATASETS/NOAA/G02135
seems down at the moment but the data I have recorded from there is:

Mar
extent area

16.44 13.13
16.13 12.92
15.61 12.62
16.15 12.99
16.1 12.84
15.62 12.48
16.06 12.66
16.08 12.65
15.95 12.75
16.13 13.84
15.52 13.14
15.88 13.44
15.5 13.35
15.47 13.41
15.88 13.71
15.58 13.47
15.32 13.27
15.12 12.83
15.58 13.24
15.66 13.5
15.4 13.47
15.27 13.1
15.61 13.57
15.44 13.36
15.49 13.36
15.05 12.93
14.74 12.67
14.43 12.44
14.65 12.49
15.23 13.17
15.16 13.04
15.1 13.11

Sep
extent area

7.2 4.53
7.85 4.83
7.25 4.38
7.45 4.38
7.52 4.64
7.17 4.05
6.93 4.17
7.54 4.66
7.48 5.6
7.49 5.31
7.04 4.81
6.24 4.5
6.55 4.46
7.55 5.37
6.5 4.52
7.18 5.08
6.13 4.38
7.88 5.58
6.74 4.84
6.56 4.24
6.24 4.22
6.32 4.31
6.75 4.55
5.96 3.98
6.15 4.01
6.05 4.35
5.57 4.03
5.92 3.97
4.3 2.78
4.68 2.93
5.36 3.42
4.90 3.02

ENSO data is not difficult to obtain. However I think the problem is what lags and how to average the ENSO data. There will be so many ways to do this, that I suspect it may be difficult to be sure you have a real relationship rather than one occuring by chance. No harm in trying and testing though.

Just a thought that as a first step it may be sensible to try to ascertain appropriate lag by correlating ENSO with temperatures in say 50N-60N and 60N-70N bands. If temperature anomalies cannot be detected there then it is unlikely there will be any real relationship with ice data.

Neven

Kelly O'Day has written a first post on the Arctic Oscillation.

Wayne Davidson also updated his website.

Christoffer Ladstein

The latest development of the debate taking place here is a sci-fi novel worthy, either it be fatalistic as The Road (McCarthy), political, The Dispossessed (LeGuin) or geoingeneering, The Mars Triology (Robinson), we are for sure living in a tipping point era, were things are most likely to worsen. In the 70ies in Norway we had a political leftist grouping taking place, mostly accademic people, living the theory of Mao: The Workers, the peasants on the bottomn new the answers, so they believed. Thereby leaving their posts as teachers, lecturers etc, applying for jobs in factories, on "the floor". The result? They met ignorant people too much occupied by everyday life and personal goals and problem, to care less upon the more global perspective. So they eventually gave up, returned to their better paid jobs were they after all had a much better opportunity to "brainwash" new generations! But then the 80ties started and you all know what happened next...

Change of topic: A few of you happen to know me through the Northern Passage blog, and I've just posted a comment were I expressed how thankful I am to have come across you very educated but sober guys, allowing a rookie along side your great knowhow. Hopefully we'll keep following Neven's track also next season:-).
Nevertheless, next saturday, I will take the 20 minute local train in to Oslo, were I plan to meet Børge, Thorleif & crew, and since most of you most likely won't be able to do so, you might have a kind of message I can bring foreward?! You have also helped them out a lot, and shared the fascination of traversing these places we're all so focused upon, but probably never will be able to visit ourselves...
So speak up, and I'll do my best to catch their attention!

Gareth

Here's a little something for you all to get your teeth into... ;-)

Phil263

Gareth
Very interestinf article, but as you say:
1) There is a lot of variability from year to year, so we won't be able to establish a trend just now. The pattern for 2002-2006 for instance is very different from 2007-2010. The last 4 years may be variability rather than the sign of a new trend.
2) PIOMAS volume measurement is only based on modelling at this stage. The poof will be in the pudding.

Gareth

Hi Phil,

The variability is overlaid on the trend, and it doesn't matter whether you take 30, 20 or 10 year trends, they're all down and the more recent years show the decline accelerating. Unless there's a big turnaround, big enough to see volume increasing significantly over a good number of years -- not just one or two -- then I'm pretty confident I'm at least in the right ballpark.

The PIOMAS modelling assimilates as much real data as is available, so while it will never be exactly right, it should never be dramatically wrong on hindcasts -- and that's what in effect were looking at.

Phil263

Gas Glo

Thanks for retrieving this data

Neven

Nevertheless, next saturday, I will take the 20 minute local train in to Oslo, were I plan to meet Børge, Thorleif & crew, and since most of you most likely won't be able to do so, you might have a kind of message I can bring foreward?!

Christoffer, if you manage to talk to one of the sailors or Olav Grinde you could tell them that it was an honour for me to link to their blog and help spread the news about their endeavour. I really enjoyed writing those blog posts.

Gareth

Yes, tell them I enjoyed their reports all summer and was pleased to help spread the word.

Meanwhile, I suspect they'll be able to sail to the North Pole in winter in the 2040s...

Kevin McKinney

Wow. Gareth, I sure hope that your "back-of-the-back-of-the envelope-scribble"* is wrong.

It's certainly hard to imagine--presumably if the Arctic Ocean were ice-free year round, you'd expect precious little winter ice anywhere in the Northern Hemisphere, which would seem to imply warming far, far in excess of anything projected officially. For example, on the edge of the Arctic Basin, Alert, NU, Canada, has a February daily maximum of -29.8 C. Contrast Sault Ste. Marie, ON, Canada, which has a January daily max of -5.5 near the eastern extremity of Lake Superior. (Unlike Alert, January is the coldest month for the Soo.)

Yet Lake Superior has exhibited significant degrees of freezeup most years since 1973, when NCDC records start. (Decreasingly so, of course, as warming has progressed.)

To be sure, the cases are very imperfectly parallel. But, BOTBOTE, you might think that the implied warming for Alert would have to be greater than 20 C. If that's anything like right, you'd need a hefty exponential trend, I'd think.

Sure hope so, anyway. It's unsettling to try to seriously imagine a change of such magnitude coming so fast. At least, it's "unsettled" me!

*(BTW, you can have BOTBOTE--that would be the INSIDE back, accessible for scribbles with a little judicious tearing!)

dorlomin

Tamino has a new post on arctic ice.
http://tamino.wordpress.com/2010/10/16/history-of-arctic-and-antarctic-sea-ice-part-1/

Phil263

Despite their obvious imperfections, these are estimates based on exhaustive study of actual data — not just cherry-picked anecdotes to support some preconception or ideology

Excellent, very informative post by Tamino . This is how we learn about sea ice!

Gareth

Kevin, Artful Dodger has posted a couple of useful papers in comments at Hot Topic. And I'm definitely going to use your acronym... I like the sound of BOTBOTE: Mma Ramotswe's new helper, perhaps.... ;-)

Daniel Bailey

Re: Kevin McKinney

You sucked me in with the Lake Superior comment.

Round about the summer of 1995 or 1996, we still had ice chunks floating in the harbor in Marquette in early June (school was just getting out for summer). As a boy in the late '60's and early '70's, the winter landfast ice along the shore's edge would occasionally reach nearly 30 feet above the flat sea ice of the big lake.

The last several years have seen little landfast ice and little sea ice. Barring weather variation, we've probably seen the last of Superior icing all the way over to Canada (my dentist will never take his fishing boat out of the water; appointments will be harder to come by).

On the plus side, that will make it more difficult for the illegals to cross into the States without getting wet...

The Yooper

Artful Dodger

A recent Journal article shows that 2.6 to 5.3 Mya when CO2 was 390 ppm, the Mean Annual Temperature in the Arctic was 19C warmer than today, warm enough for a perennially Sea Ice free Arctic:

"Significantly warmer Arctic surface temperatures during the Pliocene indicated by multiple independent proxies", Ballantyne et.al.Geology 2010;38;603-606

Kevin McKinney

Gareth, glad you didn't take my maunderings amiss--and you're certainly welcome to the acronym. Thanks for the pointer back to Lodger's comments, which I will definitely check out. (And you run a good blog, sir!)

Daniel, I may have "sucked you in," as you put it, but you just paid me back with an acute nostalgia attack! (And what's that crack about the illegals? Can't you cross at the Soo anymore with a shopping bag for passport?)

Lord Soth

NEWS Flash: Pettermann A and B reunites and had children.

http://www.ec.gc.ca/glaces-ice/default.asp?lang=En&n=D32C361E-1&wsdoc=B75BC3BC-8FD3-45D2-AA65-FDF066FB0231

It looks like that Petermann B caught up with Petermann A, as A spun around in loop-du-loops as it entered Baffin Bay over the past month. Petermann B then birth Petermann C and D.

Read all about it here

http://www.ec.gc.ca/glaces-ice/default.asp?lang=En&n=D32C361E-1&wsdoc=082CD667-6A9B-4205-AE25-A12B00D4E32B

Wow Im amazed how this thing is breaking up.

Wayne Kernochan

Has anyone noticed that average mean temperature above 80 degrees north has taken a big spike in the last ten days, to the point where it has returned to the temperature around early September -- about 10 degrees Kelvin above average? Could someone suggest a reason for this?

Neven

Thanks for the update, Lord Soth. So PII-A and PII-B are making babies, are they? It's a bit incestuous, but I'll congratulate them anyway.

Welcome, Wayne. It could be that it has something to do with the sea water releasing its heat content before freezing up. This warm air gets blown over the area 80N and the thermometers shoot up. You see that happening every year, in the last few years the spikes have been perhaps a tad more spectacular.

Kevin McKinney

Having duly read the references that Lodger posted over at Hot Topic, and having mulled a bit on Lodger's reference here, the question that remains is "how soon?" Gareth's "BOTBOTE" calculation suggested a perennially ice-free Arctic was possible by 2043. And one of Lodger's paper said that according to their modeling studies, an Arctic that was merely seasonally ice-free was not a stable state.

My estimate suggested that that would imply temperatures more than 20C warmer in the Arctic--though that was even sketchier than BOTBOTE. (But I won't attempt a further acronym along these lines, mercifully.) Then Lodger's Ballentyne et al reference gives 19C warmer as the figure for the ice-free Arctic.

Usually the Arctic amplification is cited as being by a factor of about 2, which would in turn imply global temperatures about 10C warmer. If it's a bit more than that--and if the main factor driving amplification is the albedo feedback, as suggested by Screen & Simmonds in their Nature paper from April, perhaps one has reason to speculate the amplification could be greater than what we've seen so far--then maybe it could be somewhere in the 5-7C range expected by 2100.

This would still be pretty stunning.

Screen & Simmonds:

http://physicsworld.com/cws/article/news/42499
http://www.nature.com/nature/journal/v464/n7293/abs/nature09051.html

Gareth

Hi Kevin, I think you need to distinguish between air temperatures and ocean heat content. It's principally the latter that's melting ice at the moment, and it will be OHC abetted by albedo flip that tips the Arctic into a perennially ice free state. At that point the air temps will be free to increase to PETM levels. Worth remembering that GCMs have a problem with coping with the very warm high latitudes during the PETM, so what they're telling us at the moment may not be very helpful...

Artful Dodger

Good paper from Nature Kevin. A full PDF is available from unimelb.edu.au: The central role of diminishing sea ice in recent Arctic temperature amplification.

I think Gareth is right in that Air temperature is a lagging indicator; latent heat transport in the Ocean is the relevant Forcing.

me.yahoo.com/a/nSjChi4X3vr8X3DRw93GkY1.cerja.8nvWk-

Here's a shot of the last 6 days of Arctic drift from http://cersat.ifremer.fr/news/scientific_results/global_mapping_of_arctic_sea_ice_drift_a_unique_database

Phil.

http://i302.photobucket.com/albums/nn107/Sprintstar400/20101012-20101018.jpg

JackTaylor

CERSAT Arctic Ice Drift by Phil @03:54

Thanks for the link - had not seen these prior to your post.

me.yahoo.com/a/nSjChi4X3vr8X3DRw93GkY1.cerja.8nvWk-

They produce it from October to May so it's only recently restarted.

Phil.

Kevin McKinney

Thanks, Gareth, Lodger--that makes sense; one of the differences between Lake Superior and the Arctic Basin, after all, is that warmer water isn't advected in to the former (and in fact there's a big whacking input of water at just about 0C every spring!)

However--and not to sound argumentative, I'm not knowledgeable enough to argue!--granted that the air temps are likely a lagging indicator, as Lodger says, still they must be coupled to some degree, right? (And probably more tightly the less ice there is.) So how fast can the water warm the air? Or, to put it another way, how much lag is there?

Say that the first ice-free Arctic winter comes in 2043, and that there's a 20-year lag before the air temperature equilibrates, more or less. Assuming that means an Arctic 20C warmer--in line with my guesstimate and also the PETM study Lodger linked--that's a warming trend of .4C per decade.

Disturbingly, that doesn't seem like a crazy number to me. I was thinking it would be, when I started this calculation. . .

Well, anyway, what do you guys think?

adelady

Kevin, have a look at #72 on this page. I've not gone to the source (because this bloke is pretty reliable), they're talking about a trend of .....

0.364C per decade. Pretty close to your 0.4C, I reckon.

http://www.skepticalscience.com/news.php?p=2&t=77&&n=412

Phil263

0.364C per decade. Pretty close to your 0.4C, I reckon.

0.364 C per DECADE right. So how do we get the Arctic +20C warmer in 2043? A quick calculation assuming a linear increase using an average of 0.4 C gives me a temperature change of 1.2 C in the 2040s.THAT sounds plausible.
Am I missing something here ?

Gareth

Kevin, I think lag is the wrong word to use. When ice is melting or forming, the sea surface (by definition) has to be at freezing point, and this keeps the air above it close to 0ºC. Have a look at the DMI Arctic temperature plot. In summer it never gets far above zero, despite all the heat coming in to the system.

However, when the ice has gone, all that heat can go into warming up the ocean and the air above it, and temps can/will rise much more rapidly.

While the sea ice cover is decreasing, you will see larger and larger parts of the Arctic with positive temperature anomalies in summer and autumn. When reductions in winter extent are showing up, you will also see big positive anomalies in winter in ice free regions. That rate of warming may be much faster than currently observed. It would be interesting to know what the models suggest might be the outcome...

Anu

CryoSat-2 was launched on April 8, 2010.
The commissioning and validation phases are supposed to last about six months - so hopefully, data will start to be released to the public soon. If anybody hears something, let me know :-)

The Principal Investigator is Professor Duncan Wingham at University College London, who was the first Director of the Centre for Polar Observation & Modelling:
http://www.cpom.org/

He's known as Britain's "ice man":
http://www.guardian.co.uk/science/2009/aug/16/arctic-ice-space-cryosat-probe
http://news.bbc.co.uk/2/hi/science/nature/8257557.stm

Here's more CryoSat-2 info than you can absorb over coffee:
http://www.eoportal.org/directory/pres_CryoSat2EarthExplorerOpportunityMission2.html

Hopefully we can all watch next summer's Arctic melt in glorious 3-D:

Kevin McKinney

If I'm reading you right, then, Gareth, you're thinking not so much of lags in a straightforward sense but of non-linearities in air temp?

Adelady, I'll check that number; you've made me curious. . .

Phil, that's why it seemed such a sane number--I dropped (or more accurately inserted) a decimal place, via the years/decades confusion! (Headslap.) (That's why a numerically-challenged fellow such as myself needs to write this stuff out, even when it seems too simple to bother.) So,

5 (decades) x .4 degrees = 2 degrees of warming.

Working the other way, 20C / 5 decades = 4 degrees/decade!

That's a "crazier" number--more in line with what my initial intuition expected. Mind you, there is the context of what happened this summer, with the Arctic south of 80 hitting 4C above baseline, according to this:

http://www.cbc.ca/technology/story/2010/10/21/arctic-warming-noaa-sea-ice.html

And the source report:

http://www.arctic.noaa.gov/reportcard/

(And--FWIW--that's consistent with my "anecdotal" observations of Nunvut weather reports this summer, where there were some pretty extended stretches where the MINIMUM daily temps were consistently above the climatological MAXIMA.)

Sorry for the year/decade confusion, folks--I'm still trying to stretch to get my head around all these various implications and suggestions.

Phil263

Kevin

Thank you for clarifying this issue. I think that a warming rate of 0.4C per decade is bad news enough as the positive feedback might trigger even greater changes in the future.

Gareth

Kevin -- yes, non-linearity is the way to look at it. The presence of melting/freezing ice represents a plateau for temperature. You'll get seasonal and regional excursions first, as you observe in Nunavut, but they won't dominate the Arctic average until the sea ice is gone. Won't be long...

One consequence of the current behaviour of the Arctic is that it makes the current generation of climate model projections less than useful. If they don't get the Arctic right, they can't by definition get the Northern Hemisphere right. It remains to be seen if the models and runs for AR5 can do any better. In the meantime we're left with a big chunk of the climate system warming well ahead of schedule -- how long before other sectors start to join in?

Kevin McKinney

Thanks.

I guess this leaves me slightly wiser, but still basically where I was, which is hoping that Gareth's prediction isn't right--clearly, though, as you say, Gareth, the current models aren't capturing what we are observing in the Arctic.

Another not-so-cheery thought.

Ah, well, at least we'll be better able to watch ice Armageddon with Cryosat. If you must watch disaster unfold, I suppose you might as well get the best look you can.

Paulus

@Kevin McKinney, I was about to write my first post here to warn against using hyperbole language such as 'Ice Armageddon' and 'disaster'. But come to think of it, these terms pretty accurately describe what is happening to Arctic ice right now.

Neven, I followed you over from the Climategate.nl blog (where we both part of a vocal AGW minority) and having lurked a few months here I must congratulate you for hosting such a wonderfully interesting blog and a courteous community.

Kevin McKinney

I know what you mean, Paulus. I have a typically Canadian preference for understatement over hyperbole. (The latter being more prevalent here in the American Southeast, where I live now.)

But the slightly ironic terms I used--partially, I suppose, as a psychological distancing mechanism for myself!--are, as you point out, pretty reflective of what Gareth is suggesting to be a real possibility. That's part of the reason for my struggles to assimilate this notion of a perenially ice-free Arctic occurring potentially during my lifetime. This is scary stuff, and disorienting to contemplate.

Neven

This is scary stuff, and disorienting to contemplate.

It sure is. If I would've known beforehand I would never have started this whole thing (be careful what you wish for).

The Rabett links to an interesting video on Arctic Ice by NOAA. The video itself is not interesting for most here, but the Rabett's remark is: "This is an interesting new direction of for reporting from government science agencies to the public on a nontechnical level. OK, they could have used someone who knows how to speak in something more varied than a monotone, but that would raise the debt.".

Werther

On 19 october NOAA came out with its 2010 report on the state of arctic GW. It gave the first official indication of record Greenland warming during last year. The graphs and maps confirmed what we could see on Rapidfire through last summer. The melt zone was broad and intense. Though there was no estimate of mass loss mentioned, it seems clear that mass loss must have been severe. Grazing through the web, I found no indication that the mass loss has any significant effect on GSL. My intuition is that the anomalous extra 2010 loss is compensated by intensified evaporation from global sea surface and La Nina. For the record, here is the map showing the extended melt period over Greenland compared to the ’79 to ’07 mean. http://i1036.photobucket.com/albums/a446/hanver1/Greenlandmeltanomaly2010.jpgI think it shows accurately what part of the icesheet is vulnerable to vanish in an amazingly short time on a geological timescale. A large part of the south tip matches with the forecast made by Rahmstorf, for instance. See the report: http://www.arctic.noaa.gov/reportcard/greenland.html
For a weather perspective: look for MODIS 22 oct Arctic Mosaic: around Jakoshavn Isbrae the melt zone is still visible, the first winter snowdeck from the end of September has melted. The melt ponds are exposed. The low winter sun exposes the low lying ice feeding channel east of the calving front up to the snow line some 60 km to the east.

Werther

Greenland melt anomaly 2010
I tried the wrong link.... this is the map I wanted to share with you all.

Neven

Thanks, Paulus! And thanks to you too, Werther.

Phil263

Werther

Sorry but i need some further clarification about what looks like a very intersesting map:
Does "d" stand for number of days of melting ( anomaly compared to the mean)?
What is 2,400 ? altitude? ice cap thickness?

Thanks and regards

Wayne Kernochan

Hi Neven. Thanks very much for your previous explanation (I just couldn't believe it could be that dramatic a temp. jump) and for a superb blog.

A propos of nothing, I tried to figure out how the next few years would play out assuming volume kept shrinking as it did this year. area/volume appeared to indicate that average depth at minimum this year was slightly less than one meter, or three feet. Assuming a negatively skewed but sort of normal distribution, that might mean a mode of about 2 1/2 feet. If we then assume volume shrinks by the same amount each year, we have 2.2 km^3 in 2011 at minimum, 0.4 km^3 in 2012, -1.4 km^3 in 2013, and -3/2 km^3 in 2014. This would, by a complete guess, mean that area would shrink to 55% of this year's maximum in 2011, 30% in 2012, 6% in 2013, and 1% in 2014 -- assuming that the ocean heating effects cited don't speed up the process starting in 2012.

I deduce from this that we have about two more years (sept. 2012) before the area/extent of ice at minimum really starts dipping fast, and three more years before the area/extent of ice at maximum really starts dipping.

Reactions? Am I completely off?

Werther

Phil hi…
I spent some time looking for the best answer to your questions concerning the NOAA map. Of course, you would get the best reliable stuff from the publisher. Follow the link. But since I like to verify what I run across as much as you do, I copied heights from Google Earth to my CAD. It must be the 2400 meter altitude line. The days-indication is what you suggest. I found web-stuff giving usual ranges between 90 melt days on the icesheet margin, up to 40 days around 2000 meters. That’s probably the average between ’79 and ’05. The 2010 map indicates a + 40-+80 days anomaly around 1500 meters. I can’t find what the number was during the latest top anomalous year (2005 or 2007?); those maps reflect only the maximum melt area over the sheet (corresponding well with the 2010 grey zero anomaly line).
The general picture is accelerating melt over the south tip of Greenland (see also Konrad Steffen quoted on Climate Change: the next generation).

Phil263

Werther

Thanks for your explanation. I am a bit surprised though that the anomaly on the coastal fringe ( around Nuuk on the Western coast and Narsaq in the south) appears to be close to zero. I guess the likely reason is that they only took measurements for the ice sheet.

Glacierchange.wordpress.com

I have been examining the transient snowline on Ryder Glacier If anybody has any images that strike them as telling for this glacier let me know.

dorlomin

http://www.esa.int/esaLP/SEMIWT1PLFG_LPcryosat_0.html

CryoSat ice mission gets clean bill of health

26 October 2010
Realising a satellite mission is a complicated task, with many milestones to pass before data are delivered to advance our understanding of Earth. However, scientists will soon have access to precious information on ice thickness as the commissioning of ESA's CryoSat draws to a close.

FrankD

Phil: I am a bit surprised though that the anomaly on the coastal fringe ( around Nuuk on the Western coast and Narsaq in the south) appears to be close to zero. I guess the likely reason is that they only took measurements for the ice sheet.

Your guess may or may not be correct - I can't comment either way, but I presume that accounts for the white area - but it seems logical to me. The anomaly should be not be evenly distributed, but should (and does) follow an S-curve. Remember this is not amount of melt, or temperatures, but days of melt.

A low altitude, there are already (relatively) a lot of days above zero. Pushing up the temp may mean more melt, but it does not switch you from "non-melt" to "melt". There is a finite number of above zero days you can have in summer. In winter, with little or no sun, its going to be mostly below zero anyway.

At high altitude, there are many days well below zero, even in high summer. Pushing up the temp from -25 to -20 still leaves you well below zero, so warming temps have no impact on the number of days above zero.

Somewhere between the coast with many summer days above zero and the ice cap with many days well below zero, there is a zone with many days that are *just* below zero. Pushing up the temperature here *does* make a big difference to the number of melt days, changing from just below to just above zero. Now, these may not be the areas with the greatest mass loss, but the are areas changing from not melting to melting, as charted on the map.

Note also that the altitude of maximum anomaly changes with latitude. Further south it is higher, but as we move north it comes down towards the coast.

FrankD

The question of timing of melt/freeze days has been dogging me a bit lately, and I've noticed more attention to the question of the long term future of winter extent, so I have a question for someone with time on their hands.

I've noticed the the Cryosphere Today Sea Ice Area graphs for individual regions trace an anomaly which "double-dips". The later freeze causes the negative anomaly to increase, but later returns to zero as the region reaches 100% coverage. The earlier thaw then increases the negative anomaly to increase again, before returning towards zero as the region reaches 0% coverage.

These fluctuations smooth out on the graphs of the whole area and are not obvious there. But if you look at the individual seas, many show this effect - a good example is Hudson Bay: http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/recent365.anom.region.13.html
The anomaly is greatest in December and July, for the reasons described above.

Now, if the end of the freeze (ie the point when that sea is 100% covered) is getting later and the beginning of the melt is getting earlier (and they continue to do so), at some point those to dates are going to overlap. At that time, the *winter* maximum will start to fall. And as the two slopes continue to push, the winter maximum will continue to fall. When the middle of the melt slope intersects with the middle of the freeze slope, the winter maximum ice will be half the current level. And then the beginning of the freeze intersects with the end of the melt, winter maximum would be zero.

An estimate of the rate (days/year) that these two slopes are moving together should enable an estimate of when a given region will be ice free in winter (although it can only be calculated for regions that are ice free in summer now).

I don't have the data for this, as I've only been capturing these individual region graphs for ~18 months (2 freezes, 1 thaw). In any case, I doubt my maths are up to it. But I wonder if anyone here wants to take the challenge?

FrankD

http://www.ijis.iarc.uaf.edu/en/home/seaice_extent.htm

Recent graphs are showing an interesting trend - the 2010 line is flattening out, and is looking good to drop back below 2007.

To continue the theme - earlier melt (record low/date from end of May to early July), later freeze (perhaps heading for record low/date at some point in November).

Perhaps my earlier comment: "These fluctuations smooth out on the graphs of the whole area and are not obvious there." was wrong.

FrankD

Okay, to answer my own question - quick and dirty and extremely crude analysis, and I only looked at IJIS data, 2002-2010, so very short data set as well. But, FWIW....

I marked the date on which extent fell below or rose above each million sq km increment between 13 million and 6 million (8 data points for each year). Below I've shown the results for 12 million and 7 million as well as the average for each group of 8 points. 13 and 6 show a lot of variation and are perhaps less useful here. Note that the average max and min extent are 14.3 and 5.3 M sq km respectively)

Melt:
12,000,000 - May 17 (Day 137), linear trend -0.0833 days per year
7,000,000 - Aug 2 (Day 214), linear trend -1.2667 days per year
Average (of 8 points)* - June 27 (Day 178), linear trend -1.0375 days per year

Freeze:
7,000,000 - Oct 14 (Day 287), linear trend +1.5167 days per year
12,000,000 - Dec 22 (Day 356), linear trend +1.2619 days per year
Average (of 8 points)* - Nov 18 (Day 322), linear trend + 1.436 days per year

*This is roughly the mid-point of the max melt/freeze season, and corresponds with an ice extent of ~9.8 M sq kms.

At present, the period during which extent exceeds 12 M sq km is 146 days and falling by 1.6 days per year. The period during which extent is less than 7 M sq km is 73 days, and rising at 2.78 days per year. The mid point of the melt season and the mid point of the freezeup are 144 days apart, and are growing further apart at a rate of 2.47 days per year.

Looking at the 12 M trend, the number of days above 12 (remember, thats 2.3 M below the current average max) reaches zero in 2100.
Looking at the Average trend, number of days between the mid point of the melt season and the mid point of the freezeup reaches 365 in 2101.
Looking at the 7 M trend, the number of days below 7 reaches 365 in 2115.

[insert more disclaimers about extrapolating into the far future from a few years of data, and more disclaimers about the crude analysis]

Just random number crunching, but the above data suggests that the current interval between the end of the main period of freeze up and the main period of melt will gradually drop to zero. When it does, winter maximum extent will necessarily start to fall. By 2100, the maximum winter extent may be only 10 - 12 M sq kms, and falling rapidly, and may not exceed 7 million from after around 2115.

As to summer minima, obviously as the period between peak melt and peak freeze increases, there will be more melting and extent will fall below current levels - to ....(?) by .....(?)

I have no idea what numbers go in those spaces. Unlike a projected drop of winter max, I expect to be around to see the summer minimum fall to low levels. I think winter extent will continue to hold at close to its current average while summer minimum drops essentially to zero, which might not be very far away at all.

Artful Dodger

Frank: The Math describing the transition to a perennially sea ice-free Arctic (your Comment October 27, 2010 at 04:42 above) has already been done: Just ask the Oracle. Read the paper, and browse follow-up papers with the "Cited by..." link.

FrankD

Thanks Lodger,

As I read that, the "tipping point" arises after seasonal ice-free conditions - that is we can expect a more or less linear decline in summer volume to continue even when we have a few summer months that are virtually ice free. But push it too far (greater than ~5 months of open sea) and you rapidly transition to perennial ice free conditions, and really there is no coming back from that.

Qualitatively, that was what I drew from the messing about above (and it was only ever meant to be messing about). I noticed that slope through the eight points I checked (ie rate of melt or freeze has been getting steeper over the last eight years* - this accounts for the extremely short timespan between my "projected" <12 m and <7m timeframes (only 15 years). Pure extrapolation creates an almost vertical line (in some cases beyond vertical!), indicating ice gains or losses of millions of sq kms per day (obviously impossible) in the future. So while such simple number crunching is obviously pretty useless, it did highlight what I see as a growing instability in the Arctic.

Now that's not too amazing - there are lots of indicators of that - but while a lot of noise has been generated about the declining summer minimum, far less has been said about the seemingly inevitable future collapse of winter area. And "collapse" appears to be the right word. It seems that if/when it goes (not for decades but eventually), it will go with a bang.

*There are good physical reasons for why the rate of change would be going up - from thinner ice in the melt season to the larger high-latitude areas in the freeze up, amongst others.

Artful Dodger

Frank: Yes, that's about how I interpreted the paper. My biggest "take-away" from these last 6 days of reading Journal articles is that once we have our first September with a sea ice free Arctic Ocean, the transition to a stable, perennial sea ice free state is irreversible (albedo flip causes hysteresis loop), and rapid (15 yr lag to establish a new equilibrium under the same forcings),

I am working on a new analysis of whether current climate forcings are sufficient to drive this transition. Stay tuned...

Mark Shapiro

Did the tip of the Jakobshavn glacier break up and drift away?

All summer there has been a long, easily visible tip that extends out in Davis Strait. I believe it is grounded icebergs that jam up the exit of the glacier. Over the last week or two the tip seems to have disappeared, with tiny bits drifting north. Look at the MODIS Arctic Mosaic:

http://rapidfire.sci.gsfc.nasa.gov/subsets/?mosaic=Arctic.2010302.terra.1km
compared to
http://rapidfire.sci.gsfc.nasa.gov/subsets/?mosaic=Arctic.2010285.terra.1km

(and others). What happened (besides snowfall)?

Phil263

A couple of weeks ago, some of us discussed the possibility of a year round ice free arctic by mid 21st century. I don't know if you are familiar with this arcticle which was published in nature in 2009 ( Sorry about the link to the abstract only, I can only get access to the full text version through my institution, hopefully some of you will be able to access the full text version as well).
These guys are talking about a summer ice free arctic between 2059 and 2079. Their projection assumes a medium future CO2 emission with atmospheric concentration reaching 450ppm.
Although the paper is hard to read for a non-specialist, I find that their assumptions and their conclusions very realistic considering the present situation of the arctic.

Artful Dodger

Phil: This article is freely available to all, here. It was published on Mar 15, 2009 but only contains Sea Ice extent data up to 2007. The PIOMAS model was not surveyed. As you can see from Figure 1, observations are already well outside the range of any these model predictions:

Boa (2009) Figure 1

Overall, this paper might have been of interest after the 2007 IPCC report, but has now been overtaken by events. Validation of models based on sea ice volume will soon be available with CryoSat-2 data.

Neven

Did the tip of the Jakobshavn glacier break up and drift away?

Mark Shapiro, it looks like it did. Well-spotted. I think I'll turn this into an animation later tonight.

Werther

Mark oct 29
A late reaction to your remark. Well noticed. I have been busy appetizing the latest NOAA meltzone map, even focusing on the Jakobshavn area. But without noticing what was happening at the mouth of the fjord on Disko Bay. On a semantic level, that is not the tip of the glacier. It is the region where all the debris melts and sheds into Disko Bay after passing the 200 m deep morane treshold. From another level, you are right. I guess a clump of debris some 5 km wide and 15 km deep has been driven into Disko Bay. I checked the winds in the past 10 days. They were mostly west to north. It may have been caused by a late meltwater flash. On the other hand, in the Danish site geus.dk is stated that the mouth of the fjord is free of ice in the autumn since the last couple of years, when the stuck icebergs have melted enough to be pushed out by a high tide. Maybe one of our friends can elaborate further on this?

Werther

My own project has been the integration of some interesting maps. The one put on CE Journal the 23rd by Tom Yulsman gave a good illustration of the Sermeq Kujalleq Fjord. I put it over the MODIS 25th map and got a tale-telling picture of the iceflow. It extends visually detectable for 60 km right into the 20-30 day extended meltzone, encircled by melt ponds. The ponds measure up to 4 km wide and 7 km2 in area.The bedrock fjord itself streches even further from the glaciers’calving front. At 80 km it drains out of the 30-40 day extended meltzone. The strongest melt anomaly happened even further east. It was centered on 125 km, where the sheet surface is 1500-1800 m over sea level. M. Pelto often stated that the calving and acceleration of the glacier is triggered by a destabilized front, not by ablation. But I wonder if there is more to investigate here.
Sermeq Kujalleq and melt zones oct 2010
The map isn't finished, I would like to go on working on it.

fredt34

Cryosat now has its own section on ESA site, at http://earth.esa.int/earth/www/area/index.cfm?fareaid=15 . Data will be available soon... for scientists, so we'll probably have to wait longer to get results (ya know, peer-reviewed and all that long stuff... that's bad for us ice-addicts).

A RSS is under construction, I'll post the link when available.

Please remember that Cryosat will live only 4 years !

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