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Gas Glo

James Annan doesn't seem to know the terms of his bet but seems willing to bet he was right.
http://julesandjames.blogspot.com/2011/02/tsukuba.html#comments

the terms were:

at no time between now and the end of the year 2020 will the minimum total Arctic Sea ice extent be less than 10% of the 1979-2000 average minimum annual Arctic Sea ice extent, as measured by NSIDC data or any other measurement mutually agreed-upon; provided, however, that if two or more volcanic eruptions with the energy level equal to or greater than the 1991 Mount Pinatubo shall occur between now and the end of 2020, then all bets are voided.

(per http://scienceblogs.com/stoat/2007/12/betting_on_sea_ice_following_t.php)

with James betting on ice staying above the 10% of 79-2000 avg min at all times upto 2020.

So should James be deluged with offers of bets? Or is Zang et al considered more mainstream than Maslowski?

idunno

Hi everybody,

If the current map referred to by Gas Glo in the link above is over 14 months old, it no longer describes the current (Geddit?) reality of the North Atlantic.

Since November 2009, and still going, there has been a much greater heat input into the Labrador Sea, originating somewhere just to the East of the Grand Banks. This has become the most persistant anomaly in the SST records. I refer to it as a diversion of the flow of the Gulf Stream.

I personally see this still relatively small diversion of the main Gulf Stream current as being recently or currently responsible for:

1. Huge air temp anomalies and the biggest pressure anomaly since records began over Greenland over the New Year;

2. The late freeze-up of the Hudson Bay area;

3. The doubling of the ice mass loss from Greenland in 2010. (And Hansen 2011 only postulates a doubling per decade, not an annual doubling.)

4. The continuing lack of sea ice up the West Coast of Greenland, and weakened accumulations of ice along the Canadian Archipelago section of the NW Passage and throughout the Nares Strait, including the very Northern exit to it. According to the TOPAZ maps, this area has been still losing ice thickness throughout the winter. And looking at recent satellite images, the land-fast ice North of Greenland is no longer land-fast. It has cracks in it along the coast.

5. There seems to be a corresponding and possibly related lack of heat at the far Eastern side of the North Atlantic, leading to a greater than usual ice extent in the Barents Sea.

I think that this heat anomaly in the SST is very significant. If the heat convected up the Atlantic ends up in the Barents Sea or the Norwegian Sea, it can spread out as (relatively) warm, and saltier water on the surface, and lose a lot of its heat to the atmosphere (and thence, partially, to outer space) Its buoyancy should mean that it and the sea ice are mutually repellant.

If it goes up the narrow channels of the Archipelago, it is forced under the sea ice. Different ball game. Instead of attacking the edge of the ice sheet, and being repulsed by the edge of the ice sheet, it can attack the whole of the exposed subsurface area. And it cannot do otherwise; it has nowhere else to go.

I do realise that I've posted here on this before. I've now looked at another thousand or so SST and ice maps, etc, and I've seen little to change my mind. It's essentially what Maslowski has modelled, but with a little fast forward because of the new direction that North Atlantic heat is now taking into the High Arctic.

My guesstimate; ice free by 2014 +/- 3 years, and the predicted remaining patch of ice at the North of the Nares Strait to go as well.

FrankD

Werther & Mark Kosir (and anyone else watching Antarctic shelves & streams),

I've found a area that might be worth keeping an eye on. Eklund Islands, at the southern entrance to King George VI sound is the best candidateI've found so far for a large calving in the near future (although no guarantees, it could still be years off!). Located about 73S 72W, the easiest way to find it is on the map here: http://en.wikipedia.org/wiki/Wilkins_Sound

http://rapidfire.sci.gsfc.nasa.gov/subsets/?subset=Antarctica_r04c02.2011038.terra.1km
Halfway down, a bit to the left of centre, a chunk about 270 sq kms (about the same size as the Petermann Ice Island, IIRC) looks like its fairly ready to let go.

Like the one in the Ross Shelf, the cracks have been there for two years at least, but have changed perceptibly. The notherern (left hand) end has widened quite a bit. At the other end, ice around it has calved away so its more exposed. The gap between the two tips of the crack has reduced from ~10 kms two years ago to ~8 kms now.

Could go tomorrow, could take years. And 270 sq km's isn't all that large by Antarctic standards, considering we see multi-thousand sq km chunks regularly. But there it is.

And speaking of Petermann Ice Island, the buoy they dropped on Fragment B is still reporting, and it's moved about half way down the coast of Baffin Island, and is passing Clyde River: http://sailwx.info/shiptrack/shipposition.phtml?call=47557

It might be visible the next time we get a clear view of the Baffin Island coast.

idunno

Hi Frank D,

I think there may also possibly be a big break-up ongoing in Antarctica a couple of hundred miles due South of Thurston Island. Don't know if this is a huge chunk of sea ice or an ice shelf...

Artful Dodger

Hi Phil. I read Jared Diamond's book over Christmas, and found it to be a thorough and serious study in past societal collapses. I think the main reasons the Vikings failed in Greenland were:

  • raised cattle instead of sheep in marginal conditions
  • tithe paid to the Church depleted grain reserves
  • refusal to supplement diet with fish protein (Atlantic Cod)

Today Cod stocks are depleted, but there is general political agreement in Greenland that the country should move towards the development of its mineral-resources sector. With a warming Climate and year-round access to sealift, this should be a good strategy for them.

L. Hamilton

Regarding climate & Norse settlements in Greenland ...

The Western Settlement (near Nuuk) was smaller and farther north than the Eastern (near Narsarsuaq). The Western Settlement apparently failed in the mid-1300s, the Eastern Settlement by the middle or late 1400s.

Cooling climate -- occuring unevenly (there were warmer and cooler years within a trend) but resulting in more frequent/extensive sea ice that hindered both trade with Europe and hunting/foraging travel, and late-arriving spring creating pressure on livestock -- was probably a contributing factor. Other factors might be conflicts but not exchange with the Thule, who had a more Arctic-adapted toolkit; partly anthropogenic or caprigenic loss of vegetation; even the arrival of the Black Death from Europe.

Regarding the climate itself, my reading of Alley's GISP2 temperature reconstruction for central Greenland shows a steep general cooling that began about !000 CE, and quickly reached mean temperatures lower than those prevailing when the Norse first settled in Greenland (ca. 982 CE).

Modern temperatures at Summit in central Greenland appear higher than any reconstruction value in the past 3,000 years, although of course that comparison comes with many caveats. It is more than 1C warmer than the height of the Medieval Warm Period, for instance.

L. Hamilton

To clarify, by "modern temperatures at Summit" I do not mean the most recent in Alley's ice core reconstruction, which ends at 1855. Rather, I'm looking at reports by Shuman et al. (2000) on 1987--99 temperature, and Steffen (2001) on 1995-99.

Phil263

@Frank D
Thanks for the very useful response. It looks indeed like there will be a lot changes in Greenland in the decades to come!

michael sweet

Maslowski is lower than other scientists. Zang is considered more mainstream. On the other hand, it will be a shorter time to see if Maslowski's prediction is correct!

Maslowski made his forecast before the 2007 reduction in ice area and looks good to me.

Phil263

Lodger @ 18.46 & L Hamilton @ 19.28

I agrre that there were other reasons than just cooler temperatures for the collapse of the Norse settlements; however the cooling climate was an amplifier, for instance the failure to supplement their diet with fish diet or seal meat had even more dramatic effects because of the recurrent failure of feed crops.

Lodger
Today Cod stocks are depleted, but there is general political agreement in Greenland that the country should move towards the development of its mineral-resources sector. With a warming Climate and year-round access to sealift, this should be a good strategy for them

Mining may be a "strategy for them" in the short term but am not sure that is a good strategy for the Earth. Locally mining operations will have a dramatic impact on the pristine environment, and destroy vulenrable habitat. Globally it will further deplete the stock of non-renewable resources, feed energy hungry economies and contribute to even more carbon emissions and pollution

Kevin McKinney

Cross-posted from Open Mind:

I've got a new article up; this one should be of interest to those who know folks in need of a primer on cherry-picking and the general inadvisability thereof; or who are excessively excited by a cold winter in their back yard.

http://hubpages.com/hub/When-Did-Global-Warming-Stop

Artful Dodger

Phil, what do you think of the Greenland plan to sell water?

Phil263

From what I have read , the Greenlandic government has been selling iceberg water for a while now. This water being "fossil" water ( it has accumulated over thousands of years), in a sense it is a non-renewable resource. But since icebergs will be melting any way and the fresh water would vanish into the sea, I cannot see that the exploitation of water would be harmful. However, the exploitation of "melting ice" could have some indirect consequences by affecting the rate of melting. So some serious impact studies would need to be done.
On my view, the exploitation of Oil by NUNAOIL is far more damaging .

FrankD

Lodger : Life imitates art...

http://www.youtube.com/watch?v=0qcFj10EtFM
"Global Warming or None Like it Hot!"

Artful Dodger

Frank, yeah mate that's the clip Al Gore included in "An Inconvenient Truth". Funny yet mostly true. I'd just add that, wrt the Arctic, greenhouse gases such as CO2 and CH4 are perhaps even more important during the long polar night, since these gases act as a blanket to trap longwave radiation emitted by open ocean (upwelling IR) . It's an important component of Arctic Amplification, and goes a lot way to explaining wx in Hudbay/Labsea this season.

Since we're on the topic of funny, I thought I'd share this picture of some of my mates that survived Yasi. Oi!

Phil263

Lodger
As long as the fridge works, she'll be right mate !!!! :-)

Greg Wellman

The Jaxa graph of arctic sea ice extent has 2011 below all other years again. Unless trends change we could be looking at more record minimums - we've already had an NSIDC record low Jan. If the March peak is at or near a record low, the melt season could be interesting.

Gas Glo

>" If the March peak is at or near a record low, the melt season could be interesting."

And if it isn't, the melt season could still be interesting :-p


87k fall in arctic area for day 0.1123 - a day when you would expect an increase of circa 30k. Does that count as a century break from expectation? ;-)

idunno

IMO, the 2010-11 season is already looking interesting. The ice extent and area graphs have been close to record lows since last September.

It seems to me that the way in which the various graphs are laid out is a cause of some confusion. As the colour changes at Jan 1, it seems to the naked eye that the Oct/Nov/Dec figures have no relation to the melt rate in the following year.

Clearly, they do, and I have been wondering if it actually isn't a bit simplistic to put so much store by the annual maximum or minimum.

If, for example, at the moment the ice area suddenly grew by a couple of million km squared, and then fell back a week or two later to the current level, would this really mean that the whole pack was much healthier?

It would mean perhaps that February was not a record low month. But January was, and the whole of the Fall/Winter of 2010 was. A much greater amount of Arctic than usual has been ice-free already in 2010/11. The nearest contender looks to me to be 2006/7.

I would not personally be able to extract them, but it seems to me that the most interesting figures would be the area of the graph between the line of actual extent/area and the average extent/area line. This would show not just the amount of ice missing, but also how long it has been missing for.

I think there is probably quite a lot of difference between a patch of sea that iced over in October, say, and one that only ices over in February. Perhaps as much as a couple of metres of thickness difference...

So, looking back at Jaxa, clearly September 2007 is a very deep low. So is November 2006. Some relationship, surely?

And yes, 2010/11 does look very "interesting"...

Gas Glo

"but it seems to me that the most interesting figures would be the area of the graph between the line of actual extent/area and the average extent/area line."

Not difficult to calculate, but for what time period? Jan 1 to date? or longer?

Gas Glo

Difference between each year and average in km^2 days:
Jan 1 to 11 Feb: 1Oct to 11Feb
2003 20686357 2002/03 62708114
2004 6801986 2003/04 33368587
2005 -9914107 2004/05 21219679
2006 -15113326 2005/06 -11983916
2007 -5222701 2006/07 -17562512
2008 4504176 2007/08 -45907976
2009 5299020 2008/09 16452959
2010 -7025353 2009/10 -26977508
2011 -14737697 2010/11 -46039073

michael sweet

The JAXA graph a week ago was tied with 2010, and 2010 ended up fairly high at the end of March. It is too early to tell what the final numbers will be, they depend on the weather for the next month.

On the other hand, the ice is now at a record low, you would not bet that it will be high any time soon.

Phil263

Michael
Totally agree with you. Nature has a way of making things more complex ( and interesting) than our expectations. We must remain humble in our predictions !

adelady

idunno "The ice extent and area graphs have been close to record lows since last September."

I like to keep it simple. http://nsidc.org/data/seaice_index/images/daily_images/N_stddev_timeseries.png

Just 2 lines, the current graph and the record low - against a background of the 79-2000 average with its 2 standard deviations way off in the unattainable distance.

idunno

Hi adelady,

Yeah, simple is best for me too. That graph helps a lot.

The point I was trying to make is that the drastic fall coming up in May and June 2007 is already presaged by the lack of ice through the period of Oct/Nov/Dec 2006. Whether or not there is a small upward blip on or around March 30 2007, which disappears a week later, seems to me to matter little.

The area of the anomaly from Sep 2006 through to March 2007 is in my opinion more important. Or, alternatively, the area of the graph below the line...

This represents in a simple graphic form, an approximation of the volume of ice that has accumulated during the winter, and which the sun, sea and surf need to chew through in the melt season.

I realise it's not the volume, but it is a guesstimate of the volume based on real world measurements. And, given that PIOMAS, TOPAZ and PIPS are all models, and CryoSat data will not be digested for about a year (see discussion on the thread above), then this guesstimate of ice volume may be one of the best currently available.

@Gas Glo - Hey, sorry, you lost me completely when you said the sums were easy!

You can clearly do number crunching; I am one of the number-crunched. I get scared that numbers that big will try to crunch me.

I hope that the discussion above makes it clearer what I meant in the first place, and have now expressed badly twice...

I'll get me coat.

Gas Glo

> "but it is a guesstimate of the volume based on real world measurements ...
this guesstimate of ice volume may be one of the best currently available"

I hope you are right but .... if it was the best measure of volume and what was going to happen in the next melt season why was 2008 and 2009 so much higher than 2007

Piomas and Topaz seem much more in agreement with each other than either against your measure.

PIOMAS
so Vol(Apr) - Vol(Sep) = Vol (reduction)
2005...25088 - 9938 = 15150
2006...24493 - 9672 = 14821
2007...22805 - 6042 = 16763
2008...23024 - 6126 = 16898
2009...21756 - 5583 = 16173
2010...20793 - 4079 = 16714

Topaz:
Date Extent Area Volume
05/22/2007 11,505,156 10,452,234 24,155,612 First day, max already passed
09/03/2007 4,313,281 3,306,845 7,350,711 Min volume
02/10/2008 12,007,188 11,620,371 18,152,117
05/07/2008 11,846,094 11,278,633 23,440,719 Max volume
09/11/2008 4,549,063 3,710,142 6,229,119 Min volume
02/10/2009 12,109,688 11,984,098 15,547,165
05/02/2009 12,244,375 11,803,745 19,104,472 Max volume
08/31/2009 4,997,656 3,906,281 5,325,341 Min volume
02/10/2010 11,938,188 11,600,502 14,203,979
04/20/2010 12,216,094 11,668,124 17,928,286 Max volume
09/21/2010 4,442,344 3,924,835 4,302,055 Min volume
02/10/2011 12,073,281 11,808,796 12,834,308 Last day, max not reached

http://topaz.nersc.no/WebData/topaz.nersc.no/Topaz_Matlab_Images/ARC_Images/ARC-20110212-surface-hice.png

http://topaz.nersc.no/WebData/topaz.nersc.no/Topaz_Matlab_Images/ARC_Images/ARC-20100212-surface-hice.png

http://topaz.nersc.no/WebData/topaz.nersc.no/Topaz_Matlab_Images/ARC_Images/ARC-20090212-surface-hice.png

Thickness is not easily measured and there are differences between Topaz, PIPS / PIOMAS, but should this thickness information be totally disregarded in favour of your method? To suggest totally disregarding them, I think you need some good reason why they are biased towards producing the steadily declining volumes that appear above.

Patrice Monroe Pustavrh

I have one question: PIOMAS has been verified against ICESat data. What about PIPS ? Is there any verification of this model for years ICESat has been active ? We have three models here, giving us some different results, and it should be clear how accurate these models are.

idunno

Hi Gas Glo,

If you've checked the maths, at it doesn't help, 'nuff said.

A couple of your points:

In Para 2, I would suggest that September 2008 was so much higher than September 2007 because Oct/Nov/Dec 2007 was higher than than Oct/Nov/Dec 2006. (Among several other factors, not relevant here).

In your last paragraph, you suggest I'm trying to disregard thickness, which is precisely the opposite of what I intended. The area under the curve represents area/extent x time. I was positing that the time that a patch of sea was frozen over was fairly directly related to how thick it would become...

Not necessarily so, perhaps. If you cross compare the third of your Topaz maps to the ones from earlier in this winter, you can see that the ice at the North of the Nares Strait, and across the North of Greenland has actually been thinning throughout January and February, and continues thinning. Before the polar dawn, and with air temperature down in the minus thirties...

A symptom of this thinning is also visible in the latest satellie images...

The cause of which is also keeping the sea ice free all up the West Coast of Greenland, and... I could go on, but I already have.

It's very clearly visible in any SST anomaly map of the Arctic or the North Atlantic. Precisely what is does under the ice will possibly be addressed by this season's Caitlin Ice Survey - the BBC's Richard Black put the story up online on 26 January. There is currently no data.

Where I strongly suspect it goes under the ice is everywhere on the latest SAT anomaly maps for the Arctic which are coloured Deep Purple.

Sorry I don't know how to put the images up here. Unlike the ice, I am a bit too old, and a bit too thick.

Gas Glo

Err I don't think I said " it doesn't help" just that you seem to be pushing it as "one of the best currently available" which I doubt.

I realise you are not trying to disregard thickness, and indeed quite the opposite. You suggested some simple calculations of average time.extent below average as a proxy for thickness. I doubt we should take that as preferencial to attempts to measure thickness. If we had no measures of thickness, then I would agree that it would sound like one of the best measures available.

The 2009 Catlin Ice survey was aimed at how long will the ice continue to be year round and concluded

"The Survey’s findings, taken in the context of decades of existing measurements by submarines, satellites and buoys, led scientists from the Polar Ocean Physics Group at the University of the Cambridge to suggest that:

•By around 2020 only 20% of the Arctic Ocean basin will have sea ice cover in the late summer. In other words, 80% of the ocean will be ice-free.
•By 2030-40 there is a significant probability that the North Pole region’s sea ice cover will be transformed into an ice-free, open ocean in summer times, thereby making it a purely season feature.
Within the scientific community a range of conclusions have been drawn regarding the timeframe for ice-free summers. Nevertheless, there is a broad consensus that such ice-free summer are a distinct possibility."

In 2011:
"This year, scientists and explorers are researching how increasing amounts of fresh water entering the Arctic Ocean may impact thermohaline circulation – a global ocean circulation system that affects climate and weather patterns worldwide."

Sounds more like looking at what happens to melt water, but yes that may well indicate looking at currents.

Wayne Kernochan

Random thoughts on patterns in Cryo sea ice area data (thx Neven):

Antarctic area at both min. and max. is not obviously either shrinking or expanding. Odd notes: in 1993, area achieved a min. well below other years. Over the last 5 years, area in most years achieved a slightly higher max, with 2007 being the highest, and 2010 the second highest. However, the highest plus anomaly year-round was not in the 2007-2010 time frame, and neither was the lowest minus anomaly.

Global area took a significant downward turn at minimum from 2005 on, with most years since having a minimum in the 14+ range, and none before that. Since global minimum appears slightly before Arctic maximum, the clear conclusion appears to be that maximum Arctic sea ice area has decreased by 0.5-1 compared to before 2005.

Btw, global area is on the downtrend again, to below 14.8, although it does not appear that it will reach the 14.392 record low in 2006. For that to happen, Arctic sea ice area would have to decrease by about 0.2, since if Antarctic sea ice area follows trend it will only decrease by about 0.15-0.2 between now and its minimum somewhere around Mar. 1.

A denier comment on a recent article on speedup in WA claimed that Antarctic sea ice extent (as opposed to area) reached a record maximum in 2010. If that's so, then it indicates a decrease in concentration (area/extent) at maximum. That would be consistent not with increasing sea ice, but with increasing sea ice fragmentation at maximum, probably causing earlier opening up of shorelines during the melting season, which would explain some of the acceleration of WA glacier flow.

The article also laid out a scenario for "collapse" of some but not all western Antarctic Peninsula (?) glaciers: these extend beyond the shoreline and have a descending "bottom", so break-off of the shelf at the end plus sea-water undercutting of their ice allows them to flow rapidly downhill into the sea.

Context, anyone?

fredt34

While Neven hibernates, arctic expeditions prepare to start...

This year we'll follow Catlin arctic on http://www.catlinarcticsurvey.com/ and on http://twitter.com/ArcticSurvey , while Michel Pontrandolfo is back in Resolute, taking final steps - http://pontrandolfo.wordpress.com/ , Google can (roughly) translate from Italian, too. Michele had to abort his trip last year, when becoming trapped by huge leads, "playing" with death after falling in cold water and having nothing more to eat.

I think that Ben Saunders plans to try again, but I couldn't get fresh news.

Expedition lists on http://www.thepoles.com/page/explist.htm seem to be dead... and no fresh news on http://www.explorapoles.org/expeditions/ yet either. Have you heard of other expeditions, guys ?

Neven

Merci for those links, Fred! I'll be using them for a blog post as soon as I dehibernate. I'm following the Catlin site, but didn't know about the others. Luckily I speak a bit of Italian.

I'll be posting the last Open Thread today...

Neven

And here it is: Open Thread 6.

Artful Dodger

Train Hits School Bus (luckily, it's a snow day so all the kids stayed home)

William Crump

The focus on current Arctic wide numbers showing Arctic sea ice extent/area as being at a low point for this date is likely to be a misleading indicator of the 2011 minimum.

The regions showing the largest current negative anomalies (see the Cryosphere Today web site) are regions which do not have any significant ice at the September minimum and do not contribute ice through transport to regions which do have ice at the minimum. Using the diminished ice extent in these regions in February as the basis for predicting a record September minimum is not a valid method.

Generally, ice extent levels in February do not provide a reliable indicator of the September level. Weather factors over the melt season are more important to predicting the September minimum than February ice conditions.

PIOMAS ice volume model numbers have not been updated since December 31, but there has been a pick up in the volume as the negative anomaly has diminished. Although this is model information and not data, it may be a better indicator of ice trends: however, there has not been a close correlation between the volume reported by PIOMAS and ice extent reported by NSIDC. The aveage ice thickness is declining, but extent is not matching the volume decline.

The declining PIOMAS model numbers may only be an indication that the Arctic has lost significant amounts of thick multi-year ice that has been replaced by thinner first year ice.. It does not necessarily show that first year ice is thinning at a rate sufficient to result in an "ice free" Arctic in the time frame predicted by Dr. Maslowski. This is the flaw in his analysis.

If first year ice in the central Arctic basin is maintaining its thickness, then an "ice free" Arctic will not occur in the time frame suggested by trend line analysis for the Arctic as a whole. The lack of decline in ice area for the central Arctic Basin at the minimum (see the Cryosphere Today charts and figure 8 in the link below) in the face of severe PIOMAS volume decline suggests that first year ice thickness has not declined significantly.

http://www.arcus.org/search/seaiceoutlook/2010/pre-release

If anyone has real data that shows that the thickness of first year ice in the Arctic Basin is declining at a rate sufficient to create an "ice free" Arctic, then please provide it. I am not denying that loss of albedo and additional heat from ocean sources is not contributing to a decline of Arctic ice. These factors are certainly in evidence in the loss of extent in areas outside the Arctic Basin, but these factors are not hitting the Central Arctic Basin with the same force as other regions. Certainly,loss of albedo is not as significant above 80 degrees north as it is for regions below 70 degrees north. As for Atlantic water heat input, much of this heat is trapped below 100 meters in the Arctic Basin and has not resulted in loss of surface ice extent or an increase in Arctic Basin sea surface temperatures sufficient to melt out all of the ice in this region.

Again, if anyone can provide data to the contrary for this region, then please provide it.

The rapid freeze up in late 2010 of ice in the central Arctic basin regions (per NSIDC MASIE charts the freeze-up reached its maximum level in these regions earlier than it did in prior years) may be an indicator that first year ice in this region will be thicker than in previous years. While ice will certainly melt quickly in 2011 in Hudson Bay, Baffin Bay, the Bering Sea, and the sea of Okhotsk, this will not result in a record minimum as these areas are always "ice free" at the minimum.

The region to monitor for indications of the September minimum is the Central Arctic Basin. See:

http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/recent365.anom.region.1.html

If ice area does not fall significantly below 4,000,000 km2 by the end of May, it is unlikely that a new minimum will occur. An "ice free" Arctic is unlikely as long as this region stays above 2.5 million km2 at the end of May.

At this point, hibernation appears to be a wiser activity than predicting the September minimum.

Jon Torrance

William,

Regarding "If ice area does not fall significantly below 4,000,000 km2 by the end of May, it is unlikely that a new minimum will occur." could you indulge me by specifying exactly how much below 4,000,000 km2 you have in mind with "significantly"? While you're at it, please also tell us what numerical probability you consider the word "unlikely" to imply. Cheers.

William Crump

Cheers Jon and thanks for going through my long winded diatribe.

Significantly below would be more than 500,000 km2.

I chose this figure because September of 2007 was about 500,000 km2 below September 2006 and prior years per the chart in the "pre-release" link I cited above.

The region came back up 300,000 km2 in 2008 and another 100K in 2009. It looks like it was 2.5 million km2 in 2010 based on the Cryosphere Today Chart In the link above.

If the ice area is at 4,000,000 km2 at May 31 then unlikely means less than 20% for a new record low. 2010 had this level and severe melt in June and early July and did not set a record.

2007 had unusual wind patterns and a severe late season melt. These conditions caused 2007 to fall below 2010 even though 2010 was below 2007 at the end of June.

Perhaps you could get both a 2010 like melt in June and early July and 2007 conditions for late July and August which would result in a new minimum record, but that would be relying on unusual weather patterns post May to create the event rather than weak ice conditions at the end of May.

As for ice free, unlikely means it will not happen in 2011 and I think the trend line analysis that is being used to suggest an early ice free date is deeply flawed.

The ICESAT data does not appear to have detected any declining trend for first year ice, although it did note a pronounced drop in the thickness of multi year ice.

http://www.nasa.gov/images/content/365869main_earth2-20090707-full.jpg

and the volume of first year ice increased, but perhaps this was due to extent expansion and not a thickening of first year ice.

http://www.nasa.gov/images/content/365871main_earth3-20090707-full.jpg

I am willing to change my opinion on this if some one can provide data showing a thinning trend in first year ice in the central Arctic sufficient to indicate that it will go the way of the Dodo, I think the trend lines for volume that FrankD was kind enough to post are only showing that the Arctic will be "ice free" of multi-year ice and I do not think they show that first year ice is declining.

Based on the extent and percentage of first year ice charts posted by the NSIDC it appears first year ice has expanded its range as it replaces multi-year ice. There does not appear to be sufficient "heat" in the central Arctic basin to stop this process.

While I agree volume has dropped, I do not think this is the only story. Even if volume falls to 1,000 km3 (it was 4,079 km3 in September 2010 per the PIOMAS model guess), that would still be sufficient to support an ice extent of 1,000,000 km2 of 1 meter thick ice or 2,000,000 km2 of half meter thick ice. Simple math like this leads me to believe that area and extent will be maintained even if volume drops.

I have not found any data that suggests that the volume of first year ice is on a downward trend line that will cause the Arctic to hit a zero volume level by 2019, although it is clear that the volume decline is showing that the Arctic is becoming "ice free" of multi-year ice at the minimum.

For now, I will follow the projections issued by Zhang et al using the PIOMAS model, which they maintain,rather than the "trend line" oriented analysis by Maslowski.

FrankD and I have had an open exchange about this at:

http://www.science20.com/chatter_box/arctic_ice_november_2010

if you have not already tired of my soap box.


William Crump

Jon:

Take a look at the September 19, 2010 TAPAZ model image and not how much of the ice at the minimum was 1 meter or thicker.

http://topaz.nersc.no/topazVisual/matlab_static_image.php?action=NA_ARC_NWA_Function&file_prefix=ARC&match_date=20100919&depth=0005&variable_name=hice

The stuff above 2 meters thick are nearly depleted, but this does not mean that first year ice can not survive at the September minimum. One meter thick after a summer of melt is pretty significant thickness for first year ice. If there is so much heat, why isn't more of the first year ice thinner than 1 meter?

The answer may be that the heat is deeper in the arctic basin (below 100 meters) and that most of the heat is in latitudes well below the region above 80 degrees north.

Jon Torrance

William,

Your response appears to confirm my initial impression that you don't actually know what the ice area in the Arctic Basin according to Cryosphere Today was on May 31, 2007. As far as I can tell, they don't make that data available more than 365 days into the past in either numeric form or in charts so that's understandable. However, using their "Compare Daily Sea Ice" tool, it doesn't look to me as through the ice area at the end of May 2007 met the criterion you're proposing for a new minimum this year being likely (or, if it did, then it appears a number of other recent years did as well). Which is fine - I think just about everyone agrees 2007 had an exceptional summer. In fact, you said so yourself:

"2007 had unusual wind patterns and a severe late season melt. These conditions caused 2007 to fall below 2010 even though 2010 was below 2007 at the end of June.

Perhaps you could get both a 2010 like melt in June and early July and 2007 conditions for late July and August which would result in a new minimum record, but that would be relying on unusual weather patterns post May to create the event rather than weak ice conditions at the end of May."

My basic point is that you don't appear to have verified and certainly haven't demonstrated to us here that the 2007 record minimum didn't result entirely from "unusual weather patterns post May to create the event rather than weak ice conditions at the end of May". If you want us to lend any credence to your theory, please go dig up data showing that there's a significant correlation between CT ice area for the Arctic Basin on May 31 and the size of the annual extent minimum.

Phil263

William,
I am certainly not an expert but everything you say in your comments makes total sense to me . Until we have data that proves otherwise, I cannot see how the Arctic Central Basin will be ice free within a decade as predicted by Maslowski. The TAPAZ map at 19 September 2010 indicates that there was a lot of Sea ice left that was 1 metre thick or thicker, I cannot see how this will be "wiped out" any time soon, unless climate conditions change dramatically. This is unlikely but I admit that it is not altogether impossible.

Andrew Xnn

William Crump:

First, it's really wonderful to see some critical thinking on this thread as I'm concerned that we tend to risk group think here. However, please consider your earlier question:

"If there is so much heat, why isn't more of the first year ice thinner than 1 meter?"

What heat?

The Arctic is warming thru several pathways. Convection, radiation and mass transfer. It's not a problem of heat per se, but of transfer. Ultimately the heat comes from the sun, although the tropics are significant source too. Taken together these mechanisms have yielded on average somewhere between 350 to 1,000 Km^3 of sea ice melting per year. At last years minimum, there was about 4,000 Km^3 of sea ice. So, we are looking at between 4 to 12 year before multi-year arctic sea ice may be gone.

Second part of your question "why isn't more of the first year ice thinner than 1 meter?"

As multi-year ice diminishes, first year ice can be expected to trend to thicker levels since it is forming at areas that were formally occupied by thicker multi-year ice. It won't be until several years after our first sea ice free arctic summer that meaningful trends may be drawn.

William Crump

Jon:

I appreciate your concerns about the data since Cryosphere Today only keeps 365 days. The current chart for the Arctic Basin showing 2010 is at

http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/recent365.anom.region.1.html

What do you see for June 1 and the September minimum?

While Cryosphere does not provide an archive file, at least I have not found one - but I wish they did, you can find prior year charts by going through other postings on the internet. It takes some effort, but here is the 2008 chart:

http://climatesanity.files.wordpress.com/2008/12/arctic-basin-sea-ice-area2.jpg

What do you see?


Here is a chart that covers from July 1, 2009 to July 1, 2010 from a previous post by Neven:

http://neven1.typepad.com/.a/6a0133f03a1e37970b013485099573970c-pi

What do you see?


I will try and dig up some more charts, but if you want to disprove my numbers just find the 2007 chart the same way I have found the 2008 and 2009 charts.

Arctic warming has made annual fluctuations like the deep 2007 drop more likely, but I do not see a trend line for the central Arctic basin that goes to zero as fast as Maslokski predicts. The low 2007 level did not prevent the Arctic ice in the central Arcti basin from making dramatic increases to levels significantly above the September 2007 minimum in 2008, 2009, and 2010.

Look at the pre-release link which appears to be using Cryosphere today information, (but I did not confirm this), and tell me what the trend is for ice in the central Arctic Basin (Area F in Figure 8). Add a data point for 2010 as this chart only went through September of 2009. Where is there a trend that shows the central Arctic Basin will be ice free any time soon?

As for predicting future ice levels, the information from Adrienne Tivy indicates that for the central Arctic Basin:

"The main predictor is preceding spring (March-April-May) multi-year ice (MYI) concentration in the Greenland Sea (17-month lag), where increased MYI concentrations are associated with increased ice area. The regression r2 and cross-validated r2 are 0.79 and 0.73 respectively; the categorical forecast skill over the training period is 65%. While the model over-estimated ice area for the 3 independent forecast years (2007–2009), the categorical forecasts of below normal ice area were correct for each year."

What do you see when you look at the TOPAZ chart - hope I spelled it correctly this time?

I am no expert, but Zhang is and he is not predicting a quick demise for Arctic ice like Maslowski does. (Zhang predicts a much later "ice free" Arctic)

I do not think weather patterns alone account for the 2007 minimum. My point is that the factors influencing the level of ice that occurs at the September minimum are very complex. I was not trying to prove that the September 2007 minimum was the result of just one factor.

My point is that using a measure based on the Arctic as a whole in February to predict a current year minimum is not valid and I provided an alternative data source for predicting the minimum based on the central arctic basin ice area as determined by Cryosphere Today at May 31 as a better predictor of the September minimum than the February Arctic wide figure.

Does it surprise you that the May 31 level of the region that makes up more than 80% of the ice at the minimum would be a better predictor of September levels than the early February levels for the Arctic as a whole, which includes regions that contribute virtually no ice to the minimum?

I do not see this as a particularly radical idea or approach.

Look where we were at March 31, 2010 and where September 2010 ended up and explain to me why the February level has any relevance to the September minimum when the March 31 level does not appear relevant.

Can you show any correlation between February Arctic wide area data and the September minimum?

The easiest manner to shoot down the view that the Arctic will not be ice free any time soon is to provide data showing that first year ice in the central Arctic basin is thinning at a fast enough rate that it will result in an ice free Arctic by 2019.

The volume charts provided by FrankD only show a decline that may be substantially attributable to the decline of multi-year ice. They do not offer any information on first year ice thickness.

TOPAZ is a model, but it does not appear to be showing a rapid thinning of first year ice. The ICESAT data did not show thinning of first year ice.

How do low ice conditions in Baffin Bay, Hudson Bay and the Sea of Oktosk in early February, have any relevance as to what the September minimum will be?

Here is another link that shows that multi-year ice has declined, but it also shows that first year ice is expanding:

http://www.nasa.gov/images/content/324873main_kwokfig4_full.jpg

I will try to find the data, but part of my point was that we do not have such data so making a prediction using Arctic wide volume or extent levels is likely to be flawed.

Peter Ellis

William: As I posted on Patrick Lockerby's blog, Arctic ice necessarily melts from the outer edge towards the centre.

You are in the position of one sharpening a pencil, who claims it will never all be gone because when you focus on the last cm of it, it hasn't changed length yet. Or perhaps one diving from a high window, exclaiming "All fine so far" as you pass the second floor windows.

You may well be right first year ice in the central basin isn't showing a year-on-year thinning trend yet. Incoming warm water currents running under the ice are [i]currently[/i] cooled before they reach the centre, by the "fringe ice" around the edges. What happens when that ice is gone? Likewise, for surface melt, currently comparatively little heat is absorbed at high latitudes because the white ice reflects the sun's rays. When the "fringe ice" is gone, and the waters immediately surrounding the the central core sit soaking in the midsummer sun for a month or more, absorbing much more heat, what then?

This is what happens when you look numerically at graphs for separate sub-regions without thinking about what's physically going on.

FrankD

William,

To avoid confusion and cross posting, can we take this to the current open thread - number 6?

I have posted a reply there.

William Crump

Thanks FrankD, I did not realize thread 6 had started.

William Crump

Peter Ellis:

You should know by now that the sharpening pencil analogy is not appropriate.

As for falling, compared to 2007, I would be more like a solar power airplane or rising helium balloon as 2008, 2009, and 2010 have been higher than 2007. It is not falling. If I am on a helium baloon and I go from the tenth floor to the 12th floor and someone says I am falling, why should I believe them?

Maybe I will fall when the helium leaks, but for now the integrity of the balloon is being maintained and I am rising, not falling.

The incoming water from the Atlantic does not stay at the surface. It is more than 100 meters below the surface. How is that going to melt surface ice?

The ice dramatically declined in the central arctic basin in 2007, but in each of the successive years since, the ice has come back. There is not sufficient heat to melt it all out at the September minimum. Winds pushing the ice into a more compact state appear to be responsible for a portion of the 2007 decline. .Loss of albedo above 80 degrees north is just not that significant if only .25 million km2 melts by the end of May or June. The sun angle is extreme and there is not much open water for it to work on.

The arctic declines and expands. A sharpened pencil just gets shorter.

If you want to use a pencil analogy, do it right and grab a separate pencil for each region and have each pencil get sharpened at a rate comparable to the rate of decline in the ice for the Arctic region it represents.

Then you can see that the pencil representing the central arctic basin never gets sharpened below 50% of its original length before the sharpener is disengaged and the pencil starts growing.

The central arctic basin is 4.25 km2. At the minimum in 2010 it was 2.5 million km2, that is 58.8%.

In 2009 it was 2.75 millionkm2 at the minimum or 64.7% before it started expanding.

In 2008 it was 2.5 million km2 at the minimum.

In 2007 it was 2.1 million km2 at the minimum

Alaska is about 1.72 million km2

Where is the trend? Why should I believe that something bigger than Alaska is going to just disappear if there is no trend?

For prior years look at figure 8 in the link below which provides minimum figures for the central arctic basin going back to 1979.

http://www.arcus.org/search/seaiceoutlook/2010/pre-release

Pick up your pencil and a ruler and draw a trend line for the central Arctic basin, what do you see?

Your pencil analogy does not work.

Stop thinking of the Arctic as a sheet of ice that stays in place and only melts from the edges inward. The Arctic ice moves. The ice that is in the Arctic Basin at the September minimum came from the Laptev and Kara Sea and other adjacent regions. It is not the same ice that was there at the March maximum.

While there is continuing study on this issue, generally the melt action is considered to occur from the bottom up (which supports your water surface water claims) rather than from the edge in. If the ice thickness is not declining in the central Arctic basin, then projections saying the Arctic will be "ice free" in a few years are all wet.

Show me data that says the Central Arctic basin is not able to maintain first year ice in September and I will accept that it will be ice free, but according to TOPAZ, the ice was at least a meter thick at the minimum.

SHOW ME DATA THAT SHOWS THE RATE OF DECLINE IN FIRST YEAR ICE THICKNESS IN THE CENTRAL ARCTIC BASIN AT THE SEPTEMBER MINMUM SUFFICIENT TO MAKE THE BASIN ICE FREE AND I WILL BUY YOU A NEW BOX OF PENCILS.

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