Polar Ice

[Admiral_Bobski]

It's also the 'meeting' of compatible species that have been 'separated' by the 'old perennial' that are now in contact and interbreeding?

We also have our Whale off Israel as another indicator of conditions changing. Had we not driven our Atlantic population of Grey whales into extinction several hundred years ago we'd be able to gauge better how long it was since the two species were 'linked' (before panama lifted out of the sea blocking the Atlantic/Pacific 'join' and forcing the evolution of the N.A.D?).

I think we'd all agree that 'evolution' is an ongoing process but ,yet again, we have a number of related instances highlighting a rapid evolution of an environment being played down as 'normal' (which it most certainly is not!).

As Oz noted we have plenty of critters that are adapted to winter white but very few that are 'white' year round suggesting a positive advantage in that configuration for the critter and it's 'selfish Gene'. To suggest otherwise is just a bit of naughtiness (to my mind) and not a serious observation.

The Inuit have names for both Grizzly and Polar Bear but only now are they combining the two to describe the new hybrid. For a people reliant on knowing their environment and inhabitants for day to day survival the lack of knowledge of such a beastie would ,to me, suggest that this is new for their race (as is the 'wasp' and Bee which the U.S. Health service have been advising them on as many folk show severe allergic responses to their stings having not been habitually exposed to them in the past.

I think you may have missed my point - I'm not suggesting that grizzly bears and polar bears have cross-bred before but we didn't know about it; I'm suggesting that although such a lovers' tryst may be novel, the reasons for it are nothing to do with lack of snow or ice but rather more to do with the movements of the species involved. No doubt that mankind has displaced species by our encroachment on their habitats - I believe this has more to do with it than catastrophic changes to their current environment.

I'm all for 'Devils advocate' to explore the In's and outs of a subject but ,to me, the weight of evidence (across the board) that the recent reduction in perennial ice is a 'novel' event, and not one of re-occurrence on a cyclical basis (yes, I know we have natural variability in the Arctic ,as elsewhere on the planet, but this is now beyond just 'natural' as our evidence shows us).

Well then you are clearly not "all for 'Devil's Advocate'", as you refuse to entertain alternative notions. Supposed "certainty" is no reason not to assess alternative viewpoints. In fact, all the more reason to assess them, to clarify that certainty.

As an aside to all of that I see that the denialistic bloggers are now attacking the very measures they were holding up as 'proof' of global cooling just 6 weeks ago? What's up with that?

Links?

CB

[Gray-Wolf]

I applaud your efforts NDS but am at a loss to understand the significance?

The high extent years are high due to ice outside the basin and ,as we are witnessing right now, such ice is fleeting and is melted out by warm water and not 'warm sun' come spring.

The Arctic basin fills with ice each year (up to now!) and it is the speed with which this ice ablates, and it's min area, that may be enlightening (IMHO) as it would give us some measure of how much reflection is going on across the central 'banker' ice over the summer months.

I also think that maybe a look at the Arctic Basins Area through August/Sept (with a view to checking any info on SST anoms) across this area would be interesting?

The work done on atmospheric temp profiles over autumn, above the Arctic basin, would also give some measure on how much heat is given up to the atmosphere before re-freeze can begin. Should this be an increasing figure (year on year) would it not point towards more heat being absorbed within the basin over summer before it's release over Autumn prior to re-freeze?

I know a lot of folk have been pointing towards ice outside the Arctic basin over the past couple of months but this is a red herring. The only ice to survive summer has historically been within the basin and it is the recent reduction in this ice, both extent and volume, that has science concerned.

As I have been at length to point out over the last 2 years some of this central basin ice ,come Sept, has been slumped/collapsed 'old perennial' and this year may be our first opportunity to see exactly where we are (with regards to end of summer ice) as this 'rotten ice' melts out and is not replenished by more collapsed perennial (as this has all but gone now). We were told last year that perennial accounted for 18% of the remaining ice but this figure was brought into question by Dr Barbers findings in sept/oct so we will now find out just how much of this ice was 'old perennial' by the time our melt is over.

[osmposm]

....their adaptations to life on the ice & in the sea mean that they are hopeless at land hunting (though they will eat human garbage, with sometimes fatal results). More importantly, their biology is very specialized, and actually needs large amounts of fat - specifically marine mammal blubber - and they cannot derive sufficient caloric intake from terrestrial food. If ice loss forces them ashore in late summer & autumn, they effectively starve, and live on their fat reserves from the spring-summer feast.

...and by coincidence a report just published concludes ".....for a while we will only see small changes in summer fasting season survival in Western Hudson Bay......[but] eventually mortality will dramatically increase when a certain threshold is passed; for example, while starvation mortality is currently negligible, up to one-half of the male population would starve if the fasting season in Western Hudson Bay was extended from currently four to about six months." See here: http://news.bbc.co.uk/earth/hi/earth_news/newsid_8700000/8700472.stm

So, yes, the evolutionary process may well kick in, and if there are polar bears that have a little more adaptability in their primarily fat-eating biology they will survive.....and the survivors' fur colour may well change - in stoats, at least, this seems to be a relatively flexible gene (see here: http://www.wildaboutbritain.co.uk/forums/mammal-forums/48193-stoat-ermine-question.html ).

But in essence I would suggest that IF - and I say "if" because I don't want to argue about that - in future there is much less arctic ice in the summer/autumn (or even less walkable-on ice in winter/spring), then polar bears with their specialized-for-ice biology and physiology will find life very hard. And if they survive at all, those that do so are likely to be progressively less and less "like polar bears", and more and more like their relatives the browns/grizzlies from whom they are thought to have split off some 150,000 years ago (there was also a specific and identifiable tooth change just 10 to 20,000 years ago). Should things subsequently cool down again, then presumably the reverse would happen - perhaps it has happened before, I have no idea, though the digestive specialization seems to be very tight and demanding, and must surely have taken a long time to emerge and solidify. Alternatively, if all the "old" polar bears had by then gone (or cross-bred with browns), a new brown bear ice adaption could evolve.

Does any of this matter? Probably not in the wider scheme of things (though I'd miss them as they look now). And their disappearance would certainly be an incontravertible proof (as if more would then be needed!) of the great change in our northern ice-cap.

Edited May 25, 2010 by osmposm

[Gray-Wolf]

Links?

CB

http://wattsupwiththat.com/2010/05/23/wuwt-arctic-sea-ice-news-6/

[BornFromTheVoid]

I applaud your efforts NDS but am at a loss to understand the significance?

The high extent years are high due to ice outside the basin and ,as we are witnessing right now, such ice is fleeting and is melted out by warm water and not 'warm sun' come spring.

The Arctic basin fills with ice each year (up to now!) and it is the speed with which this ice ablates, and it's min area, that may be enlightening (IMHO) as it would give us some measure of how much reflection is going on across the central 'banker' ice over the summer months.

I also think that maybe a look at the Arctic Basins Area through August/Sept (with a view to checking any info on SST anoms) across this area would be interesting?

The work done on atmospheric temp profiles over autumn, above the Arctic basin, would also give some measure on how much heat is given up to the atmosphere before re-freeze can begin. Should this be an increasing figure (year on year) would it not point towards more heat being absorbed within the basin over summer before it's release over Autumn prior to re-freeze?

I know a lot of folk have been pointing towards ice outside the Arctic basin over the past couple of months but this is a red herring. The only ice to survive summer has historically been within the basin and it is the recent reduction in this ice, both extent and volume, that has science concerned.

As I have been at length to point out over the last 2 years some of this central basin ice ,come Sept, has been slumped/collapsed 'old perennial' and this year may be our first opportunity to see exactly where we are (with regards to end of summer ice) as this 'rotten ice' melts out and is not replenished by more collapsed perennial (as this has all but gone now). We were told last year that perennial accounted for 18% of the remaining ice but this figure was brought into question by Dr Barbers findings in sept/oct so we will now find out just how much of this ice was 'old perennial' by the time our melt is over.

There is no real great significance for the years averaged, just another statistic to look at, like having the yearly CET instead of just the max and min. Weighting the extent against surface solar radiation over the course of the year would be more useful I know!

What would be particularly interesting would be trying to find out the variations in monthly albedo and then adding them up to get a yearly albedo. But obviously, with so many variables such as solar radiation and ice extent at different latitudes, cloud cover, ice age, snow cover on the ice, etc, all having varying effects on albedo, getting even a rough estimate will prove difficult and time consuming at least.

When does cryosat start reporting by the way?

I'll get the average extent from April-August and post that up in a little while seen as that's the period when the arctic recieves the most sunlight, as apposed to September when the minimum usually is...

[BornFromTheVoid]

Got the averages from April 21 to August 21

2009 - 9,967,578km2

2008 - 9,888,187km2

2007 - 9,512,060km2

2006 - 9,646,071km2

2005 - 9,822,043km2

2004 - 10,070,994km2

2003 - 10,216,019km2

I know that there are various other factors involved, but at least albedo from sea ice during high summer when it's needed is on the rise and quite close to 2004. Would be worse if we had very negative anomalies during the time with the most sunlight. I'm guessing by September that the suns rays are at a low enough angle to mostly reflect off any open water present in the Arctic ocean.

Still, 3 years isn't really enough to be a trend, and if the ice decline over the last month or so continues so that we have a large negative extent anomaly for high summer, that could really accelerate the melting right through to September and then the increase in SSTs would slow ice growth into October.

I guess for now we just have to wait and see what happens!

Edited May 25, 2010 by NaDamantaSam

[cyclonic happiness]

I'd have thought the polar bear's permanently white coat (and other changes from its cousin the Brown/Grizzly Bear) strongly suggests that it did evolve to live and hunt primarily on ice and snow, no? I am unable to see any other evolutionary advantage in the variation - indeed, it would be a distinct disadvantage for a predator on a non-white background. If the ice/snow was only seasonal, the fur would presumably have evolved to go white only in winter - like, for example, the arctic fox, arctic hare, ptarmigan and northern populations of stoat. For the same reason most arctic species of seal have evolved white natal fur - to camouflage the pups on the ice where they are born.

Not really - their adaptations to life on the ice & in the sea mean that they are hopeless at land hunting (though they will eat human garbage, with sometimes fatal results). More importantly, their biology is very specialized, and actually needs large amounts of fat - specifically marine mammal blubber - and they cannot derive sufficient caloric intake from terrestrial food. If ice loss forces them ashore in late summer & autumn, they effectively starve, and live on their fat reserves from the spring-summer feast.

As for size, some populations of their Brown Bear relations - in particular the Kodiak - are quite as big as they are, and with terrestrial skills (and more omnivorous biology) would certainly out-compete them.

So in otherwords, they have accidently fallen into an evolutionary trap to which eventual extinction would have always been inevitable?

And maybe they lived more around the icecaps of greenland and the canadian islands, and enough of the northern lands would be snowcovered enough for long enough each year for this twist in evolution?

Anyway it's still ironic that, even if the icecap does melt, be it manmade or not, the polar bears will never die out beacause they have man to save them and feed them, and mybe move then to antarctica (which they'd have to rename of course..."antiantarctica"??

Absolutely! Such reasoning will take some obscuring...

slightly patronising outburst B)

[Gray-Wolf]

Still, 3 years isn't really enough to be a trend, and if the ice decline over the last month or so continues so that we have a large negative extent anomaly for high summer, that could really accelerate the melting right through to September and then the increase in SSTs would slow ice growth into October.

I guess for now we just have to wait and see what happens!

I'm a little concerned over the data from 98' through 09'.

as we can see ice volume has plummeted since that time and with Dr Barbers accounts of 'rotten ice' at the end of autumn last year

http://www.agu.org/p...9GL041434.shtml

and his witnessing of a multi mile ice flow collapsing in less than 1/2 an hour we must accept that a significant amount of the ice come the end of melt is 'rotten ice' . In other words ice comprising of the remnants of collapsed multi year floes.

Dr Barber estimates that in 1981 the ice comprised of 90% perennial ice, today that figure is 18%. Those massive islands of ice have collapsed and as the 'volume' plot shows this has accelerated since 98'.

This year we may face the spectre of an end of season not propped up by collapsing perennial (as none is now left) and the 'real' amount of open water will be revealed.

NSIDC seem to be aware of the way things are going as their release of yesterday shows;

Boulder, CO, United States (AHN) -

"Latest data from the National Snow and Ice Data Center in Boulder, Colorado, shows that Arctic sea ice is set to recede to a record low this year. Based on the center’s satellite information, ice coverage this year is equal to the record-low 2007 level. The average extent of Arctic sea ice was 14.69 million square kilometers in April, which is just 310,000 sq. km. below the 1979 to 2000 average. The rate of decline in ice coverage for the same months was 41,000 sq. km. (16,000 square miles) daily.

The center pointed out the ice extent for April was the largest for that month in the past 10 years. It laid the phenomenon to changing wind patterns that caused older, thicker ice to move southward along Greenland’s east coast, where it will probably melt in summer.

Mark Serreze of the center forecast the ice decline this year would even break 2007’s record.

To show the extent of ice melting, University of Manitoba researcher David Barber said in 1981, 90 percent of the Arctic ice pack was made of multi year ice–the kind that stops ships. Now, multi year ice has dwindled to 18 percent."

The records you seek to use may prove meaningless if from now on we have to face an ice min well below 07' as the amount of open water this reveals is far greater than any of the totals you have chosen to use.

Edited May 25, 2010 by Gray-Wolf

[songster]

I'm a little concerned over the data from 98' through 09'.

That graph only has data through '04. It's certainly worrying, but I'd like to know how their model fares when you add in the next 5 years of data. The PIOMAS data are marginally more encouraging, though still deeply worrying. The graph you link shows an average total volume of ~25,000 km^3 of Arctic sea ice, falling at ~1200 km^3 per year since ~1998. The PIOMAS data doesn't give absolute figures, only the anomaly, but the slope is 3,400 km^3 per decade, or 340 km^3 per year. This is 3.5x slower, suggesting that ice-free Arctic won't happen until 2050 or so - unless PIOMAS is using a different baseline figure...

Edit: baseline data for PIOMAS is here

http://psc.apl.washington.edu/ArcticSeaiceVolume/images/PIOMAS_daily_mean.png

Eyeballing that, I'd say the average baseline is about 21,000 km^3, and the minimum baseline around 13,000 km^3. At 340 km^3 of loss per year, that puts complete summer Arctic ice loss somewhere around 2040. Although that said, the most recent daily PIOMAS graph has us well ahead of that, so...

Not good news however you cut it.

Edited May 26, 2010 by songster

[Gray-Wolf]

Hi Songster! the above 'volume anom' plot runs from 1980 and further highlights my concerns about the loss of the 'old perennial'. If the current plots for M.Y. ice still include the 'rotten ice' (I've not seen any updates since Barbers paper on Dec 24th) then I don't think we can even put much faith on 'where' the M.Y. ice currently resides. The flush out of visibly older floes through Fram over the winter means that most of the strip shown down the East Coast of Greenland has now gone and what's left is melting fast. The ice at the top (north) of Greenland was also plotted as M.Y. ice and is now also on the move into Fram. This leaves the plume across Beaufort (where Barber found his 'rotten ice' and saw it forming with the collapse of the multi mile floe) which is being driven into the Bering Straights (which melts out each summer).

The only remaining strip of M.Y. runs behind Svalbard and north beyond Frans Joseph land. Catlin reported covering over 500 nautical miles to cover the 286 n.m. on his trek this year so this section is flowing South at quite a rate towards Fram.

All in all I do fear we'll see what the Arctic Ocean should have looked like since 07' in late summer now we have little of the 'old perennial to slump into it and spread out.

If we recall Dr Barbers multi mile chunk was 3m above sea level (they landed the chopper on it as they approached) so this puts a good 14m below the water line .He reports that the swell (from the Siberian side of the basin) smashed it into 2m slivers over a half hour period. You can imagine how much more water these 'slivers' covered compared to the original ice island.

EDIT: http://arctic.atmos....m.region.2.html

C.T. now shows no areas with positive anoms as Bering has just slipped back to the baseline. Sadly, as you can see, many of the other sea ice areas never even made the 'baseline' over the past 12 months and many are already into big -ve anoms.

Check the Canadian Archipelago esp. the growth spurt in oct/nov. Could this be a signature of perennial 'collapse and spread' as the surrounding areas do not show this 'growth spurt' which must have been very local if weather based (sorry Beaufort also shows an oct spike...but this is where we know ice was collapsing at that time.....)

Edited May 26, 2010 by Gray-Wolf

[BornFromTheVoid]

Just to compound how badly the ice has been faring this month thus far, here are the average daily melt rates from the 1-25th of May since 2003;

2010

70,931.24km2/day (1st)

2009

55,843.72km2/day (2nd)

2008

49,568.72km2/day (3rd)

2007

45,081.28km2/day (4th)

2006

42,818.76km2/day (6th

2005

41,775km2/day (7th)

2004

43,393.72km2/day (5th)

2003

39,100km2/day (8th)

Average of the 8 years 43,211.71km2

The Arctic ice is melting way faster than average so far, melting 64% faster than the rolling average actually! We are 2nd from bottom in the series now and just 33,750km2 from being last. First time a year has gone from top to bottom in less than a month perhaps?

[Gray-Wolf]

I believe so NDS! though things are not as dire as that picture paints with the 'late spurt ice' ,being a huge ice tongue out from the Bering straights into the Pacific, was always going to melt out quite rapidly come spring (even if some folk hoped it wouldn't and called it a 'recovery').

The true worry is the ice levels within the basin itself as ,if the reports of ice thickness are to be believed, much of this ice could go over summer. We are now approaching the time that this ice will start to show a more rapid fall off from now through August (as the C.T. plots show).

My prattling about the loss of perennial will also become apparent in late Aug/early Sept as the 'slowdown' which may have been augmented by collapsing 'old perennial' will not be as marked with little or no collapsing ice left to spread out across the open waters. Time will tell.

[BornFromTheVoid]

I believe so NDS! though things are not as dire as that picture paints with the 'late spurt ice' ,being a huge ice tongue out from the Bering straights into the Pacific, was always going to melt out quite rapidly come spring (even if some folk hoped it wouldn't and called it a 'recovery').

That's true alright, but still, if we the average from the 5th, or even the 10th up to now, 2010 is still averaging over 60,000km2/day. Yesterday alone lost 98,000km2, so the melt rate hasn't changed all that much.

Did ice around the Laptev Sea used to be perennial? That seems to be dropping away already, infact along the much of the Siberian coast ice extent is dropping

[Gray-Wolf]

I am not too sure NDS, The East Siberian sea (and Laptev) seemed one of the areas that lost it's ice first in the early noughties and ,as such, has also had many years of mixing of the ocean layers so will not hold onto the ice as well as it used too. I'd imagine that both East Siberian and Laptev will lose their ice quite rapidly though.

It's the Arctic Basin ,Beaufort and Canadian Archipelago that I'll be keeping an eye on through summer. Beaufort already looks well fragmented and is purported to hold a lot of the remaining 'multi year ice' , the Canadian Archipelago used to be a veritable fortress for the 'old perennial' but 07's melt cleared out a lot of room for the collapse of the bay ice/inlet ice which has clogged the region the past two years.The fast breakup of the ice either end of the deep water channel of the NW Passage makes me wonder about an early opening of the passage in Aug. The Arctic Basin itself has been plagued with large leads all winter making me suspect that much of the ice there was impacted by the warm winter it endured but also the 'mixing' of the ocean there these past 2 summers.

If you look at the buoy movements over the past 2 months you'll see that it all appears quite mobile (not as 'locked in' as we're used to) so I'm wondering if we'll get open water on the North Pole Cam pretty soon?

Edited May 26, 2010 by Gray-Wolf

[Yorkshiresnows]

We only have accurate Ice measurement data from the last 30 years or so (satellite measurements) .... all in a period of positive PDO state.

There is however, plenty of anectdotal evidence to suggest that there was indeed as much ice loss as now. Proxy data from the middle ages and prior to then (Roman times) have shown at least a possibility that there was low ice up North. Certainly that Northern hemisphere temperatures were consistently high.

The Northwest passage was open in the early 40's and Vikings were for several centuries farming Greenland.

These are all facts and you can look for them yourself, there have been links to books and publications made ... go and read them.

Y.S

I know I shouldn't but couldn't help myself - just to back up my earlier post, before we all get too hung up about the Ice melt coming this year !!

2,000 Years of Global Temperatures

This graph shows the average of 18 non-tree ring proxies of temperature from 12 locations around the Northern Hemisphere, published by Craig Loehle in 2007, and later revised in 2008. It clearly shows that natural climate variability happens, and these proxies coincide with known events in human history.

Guess this more 'complacency' over humanities role .... or not ...... in polar ice retention.

Y.S

Edited May 26, 2010 by Yorkshiresnows

[jethro]

What are those non-tree ring proxies? Where were those 12 locations?

[Gray-Wolf]

What are those non-tree ring proxies? Where were those 12 locations?

From here;

http://nap.edu/openb...09102251&page=2

it seems to follow the tree ring proxies most closely of all??

or from here;

http://www.globalwarmingart.com/wiki/File:2000_Year_Temperature_Comparison_png#Description

with the light blue (northern tree ring proxies) being the closest???

Edited May 26, 2010 by Gray-Wolf

[Yorkshiresnows]

What are those non-tree ring proxies? Where were those 12 locations?

Hi, The abstract from the paper is re-printed below.

No time ... on travels, but this includes the links to the raw data. The link to the paper is here:

http://www.econ.ohio-state.edu/jhm/AGW/Loehle/SupplementaryInfo.pdf

Tree-ring data has been shown to be flawed and hence non-tree ring proxy data is what is generally accepted as being the most reliable data in attempting to re-construct past temperatures.

"Tree ring data have what is called a “divergence problem†in the late 20th Century where the tree ring data data suggests cooling, when in fact there has been warming. This, by itself, should cast serious doubt on whether tree ring reconstructions (such as Michael Mann’s famous “hockey stick†curve) can be used to estimate past global temperature variability.

Supplementary information by J. Huston McCulloch for

"Correction to: A 2000-Year Global Temperature Reconstruction Based on Non-Tree Ring Proxies," by Craig Loehle and J. Huston McCulloch

Jan. 10, 2008

Loehle and McCulloch (LM, submitted to Energy and Environment as a correction to Loehle 2007) construct a Global Temperature Reconstruction for 16AD – 1935 AD based on 18 peer-reviewed published non-treering proxy series. These are the same 18 series used by Loehle (2007), with the dating of 4 of the series corrected by a 50-year shift. Each series was newly interpolated and smoothed with a 29 year moving average by CL over the period 1AD – 1980AD, to the extent available. Each series was converted to bimillennial anomalies by subtracting out its own mean. The global temperature reconstruction is the unweighed average of these anomalies. Because the number of available series drops abruptly from 11 to 8 in 1935, i.e. to less than half the maximum number of series, the reconstruction was terminated in 1935. The 18 smoothed series and their residuals about the global average are individually graphed at the end of this note. The smoothed series, as used in the reconstruction, are online via <http://www.econ.ohio-state.edu/jhm/agw/> . Links to the raw data have been compiled by Stephen McIntyre of climateaudit.org, at <http://www.climateaudit.org/?p=2393>.

Hope this helps?

Cheers

Y.S

[songster]

What are those non-tree ring proxies? Where were those 12 locations?

<cough> It probably took you longer to post this than it took me to find the data :-)

* Google "Craig Loehle 2007" (no quotes needed.

* Visit the first hit: http://www.ncasi.org/publications/Detail.aspx?id=3025

* Download the PDF

The PDF appears to be a free download (although that may be because I'm coming at it from within the university network).

For the record, the proxies are:

1) GRIP borehole 18O temperature (Dahl-Jensen et al., 1998);

2) Conroy Lake pollen (Gajewski, 1988);

3) Chesapeake Bay Mg/Ca (Cronin et al., 2003);

4) Sargasso Sea 18O (Keigwin, 1996);

5) Caribbean Sea 18O (Nyberg et al., 2002);

6) Lake Tsuolbmajavri diatoms (Korhola et al., 2000);

7) Shihua Cave layer thickness (Tan et al., 2003);

China composite (Yang et al., 2002) which does use tree ring width for two out of the eight series that are

averaged to get the composite, or 1.4% of the total data input to the mean computed

below;

9) speleothem data from a South African cave (Holmgren et al., 1999);

10) SST variations (warm season) off West Africa (deMenocal et al., 2000);

11) SST from the southeast Atlantic (Farmer et al., 2005);

12) SST reconstruction in the Norwegian Sea (Calvo et al., 2002);

13-14) SST from two cores in the western tropical Pacific (Stott et al., 2004);

15) Mean temperature for North America based on pollen profiles (Viau et al., 2006);

16) A phenology-based reconstruction from China (Ge et al., 2003);

17) Annual mean SST for northern Pacific site SSDP-102 (Latitude 34.9530, Longitude 128.8810) from

Kim et al. (2004);

18) Spannagel Cave (Central Alps) stalagmite oxygen isotope data (Mangini et al., 2005).

[Gray-Wolf]

Lots of ocean based proxies in there? Phrenology from a single region??? and a smattering of cave proxies.......hmmmmm, O.K.

Anyhoos , back to this years ice melt. 64% faster from may 1st to may25th eh ? than any of the other past 8 years eh

?

Do we think that we can exceed this astonishing melt rate over the first 25 days of June or do we feel that the current rate is unsustainable?

I'd imagine that this could easily be matched over the June period as the melt transfers into the basin proper ( the current rate of descent on the graph and not 64% faster than the past 8 years!!!!) as the ice across swathes of the basin is extremely thin and fragile and it looks like we'll be seeing quite a bit of sun up there over June/July if the slightly neg AO continues.

Anyone else any thoughts for June?

The other point is the anecdotal reports we will now start hearing from the indigenous folk around the Arctic circle. Should this be a 'common occurrence' (I'm now hearing of a 'recognised 60yr cycle in the arctic ....YAWN....) we should be able to compare such reports with those of 2 generations ago (not as if word of mouth cultures depending on their environment for survival would 'forget' such important info now is it???)

[4wd]

I would imagine that the easy bits round the edges have been melted and the rate will drop off markedly despite the 24 hour daylight.

[jethro]

<cough> It probably took you longer to post this than it took me to find the data :-)

Lol, possibly.

Apologies for taking the lazy route, manically busy at the mo and dropping in and out of here briefly.

Thanks to you all for the additional info.

Tree ring proxies....there was something last year/early this year about Solar output showing up in tree rings, I'll try and find it when I get a moment.

[Solar Cycles]

Lol, possibly.

Apologies for taking the lazy route, manically busy at the mo and dropping in and out of here briefly.

Thanks to you all for the additional info.

Tree ring proxies....there was something last year/early this year about Solar output showing up in tree rings, I'll try and find it when I get a moment.

Edited May 26, 2010 by Solar Cycles

[songster]

I would imagine that the easy bits round the edges have been melted and the rate will drop off markedly despite the 24 hour daylight.

... so it'll run contrary to every single year ever recorded? That's a... brave... pronouncement.

Melt ALWAYS speeds up in June/July. The reason for this is trivially simple: the Arctic Ocean is a pool largely surrounded by land. There just isn't as much ice at lower latitudes, because globe's surface at those latitudes is covered by land, not water. Once the melt-line moves upwards into the basin proper, the Arctic Basin ice is free to start melting from all sides inwards towards the Pole.

[stewfox]

Lots of ocean based proxies in there? Phrenology from a single region??? and a smattering of cave proxies.......hmmmmm, O.K.

Anyhoos , back to this years ice melt. 64% faster from may 1st to may25th eh ? than any of the other past 8 years eh

?

Do we think that we can exceed this astonishing melt rate over the first 25 days of June or do we feel that the current rate is unsustainable?

I'd imagine that this could easily be matched over the June period as the melt transfers into the basin proper ( the current rate of descent on the graph and not 64% faster than the past 8 years!!!!) as the ice across swathes of the basin is extremely thin and fragile and it looks like we'll be seeing quite a bit of sun up there over June/July if the slightly neg AO continues.

Anyone else any thoughts for June?

The other point is the anecdotal reports we will now start hearing from the indigenous folk around the Arctic circle. Should this be a 'common occurrence' (I'm now hearing of a 'recognised 60yr cycle in the arctic ....YAWN....) we should be able to compare such reports with those of 2 generations ago (not as if word of mouth cultures depending on their environment for survival would 'forget' such important info now is it???)

Not sure but shall I make some humble pie in case the non believers are caught out ?

Interesting comment

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In principle, SIC data could have errors of 10% at most, particularly for the area of thin sea ice seen around the edge of sea-ice cover and melted sea ice seen in summer. Also, SIC along coastal lines could also have errors due to sub-pixel contamination of land cover in an instantaneous field of view of AMSR-E data.

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Thinner ice may lead to more ‘errors’

Could the real extent be 12.5m ??