Polar Ice Extent

[NorthNorfolkWeather]

Anyone have today's figures ( or a URL to retrieve them)?

[pottyprof]

I don't doubt we've contributed to the warming in recent decades but I want to know how much?

By every bit of ice that isn't there less the ice that would have melted naturally??

That covers it quite well.......................

[BornFromTheVoid]

Anyone have today's figures ( or a URL to retrieve them)?

http://www.ijis.iarc.uaf.edu/seaice/extent/plot.csv

Has been adjusted up once more to nearly 70,000km2 today!

[jethro]

By every bit of ice that isn't there less the ice that would have melted naturally??

That covers it quite well.......................

By Jingo, I think he's got it!

Clear as mud now, thank you my sweet.

[stewfox]

LOL. The only evidence available suggest it is getting thicker. There is NO evidence to suggest is getting thinner. But the only evidence shows a substantial increase in ice thickness. Post facts that will counter my claims.

I dont think anyone can

I think something that needs to be taken into account with regards this rapid "re-freeze" is that so far it's been mostly wind driven and not so much the forming of new sea ice. For a few weeks we had the ice compressing around the north Greenland coast but in the last 7 days the wind pattern that caused that has reversed and we're seeing that ice spread out again, upping the extent figures. There is of course some new sea ice being formed but the majority of this near record "re-freeze" is just ice spreading out.

Here is the air temperature anomaly from the 20th-24th this month, roughly the time when this growth in extent began, up to the most recent day available

I think we can safely say, it isn't the cold air causing this apparent rapid growth.

At least we now know what is causing the rapid re freeze/IJIS growth and I assume this was partly responsible for the late decline earlier in the month ie wind compressed the ice ?

Seeing the final state of the pack in 2007 it did seem to be more robust , did we have a more robust pack end of final melt 2010 ?

Edited September 27, 2010 by stewfox

[oldsnowywizard]

I think something that needs to be taken into account with regards this rapid "re-freeze" is that so far it's been mostly wind driven and not so much the forming of new sea ice. For a few weeks we had the ice compressing around the north Greenland coast but in the last 7 days the wind pattern that caused that has reversed and we're seeing that ice spread out again, upping the extent figures. There is of course some new sea ice being formed but the majority of this near record "re-freeze" is just ice spreading out.

Here is the air temperature anomaly from the 20th-24th this month, roughly the time when this growth in extent began, up to the most recent day available

I think we can safely say, it isn't the cold air causing this apparent rapid growth.

[/quote

i dont think its quite as simple as that.. the ice will have a very similar thickness in most areas.. just because the wind blows it in one direction does not mean it stacks up on top of each other.. and then un stacks when the wind blows it in another direction..to have that much impact we would need storm force winds and massive ocean swells which has not been happening recently.. I would put the refreeze down to the past 2/3 weeks of melt water being refrozen as it has not had much mixing and the -20 temps up there.. to use a GW analogy dump ice in a bath and then blow blow wind against it.. as most of the ice is below the surface it cant actually stack unless it is pressed up against something sturdy like land or a great big iceberg 30 metres deep and a few miles wide.. GW tells us there arent any of those left so the ice would simply move in one direction as one.. with small gap filling.. nothing to suggest a great big 100k increase one day and 70k the next!

[BornFromTheVoid]

i dont think its quite as simple as that.. the ice will have a very similar thickness in most areas.. just because the wind blows it in one direction does not mean it stacks up on top of each other.. and then un stacks when the wind blows it in another direction..to have that much impact we would need storm force winds and massive ocean swells which has not been happening recently.. I would put the refreeze down to the past 2/3 weeks of melt water being refrozen as it has not had much mixing and the -20 temps up there.. to use a GW analogy dump ice in a bath and then blow blow wind against it.. as most of the ice is below the surface it cant actually stack unless it is pressed up against something sturdy like land or a great big iceberg 30 metres deep and a few miles wide.. GW tells us there arent any of those left so the ice would simply move in one direction as one.. with small gap filling.. nothing to suggest a great big 100k increase one day and 70k the next!

When I said compressed I didn't mean stacked. It was more so based on the fact that during much of the summer the ice was very fragmented, even across the North Pole. During August we had a weak dipole set up that allowed the ice to slowly get pushed in towards Greenland. The winds, while not storm force, have been blowing the ice back towards the Bering side of the Arctic. This can be seen on the CT animation here You can see how the concentration back over a month ago was very low across the Arctic, and then as the wind pattern pushed it towards Greenland, the concentration here increased by quite an amount

When you have a pack edge probably several thousand kms long, it doesn't take a whole lot of spreading to rack up impressive daily growth figures. Obviously we're going to have some new ice growth on top of that too, but the cold surface temperatures have not been that widespread, never really moving out of 80N, where the main body of ice is.

If you want an example of how fast ice can move on water though, take a quick glimpse at the modis images of the Nares strait over the last few weeks!

[barrel1234]

I thought that I would throw a post in to make everyone think about how strong their views are. I try to remain as open minded as possible but regarding arctic sea ice I have to admit that I think that the 'ice crisis'(or lack of ice) will probably come down to a fuss over nothing. However I do think quite regular what would need to happen in order for me to change my stance on the matter. Personally I think that I would need to see at least 1 year of sub 2007 ice levels along and/or a few other very low ice years close to the 2007 level (mainly referring to the minimums) within the next say 10 years or so (and that is with existing data sources) Remember if you were just talking about average luck over 10 years you would expect to have a minimum year of the chance of 1 in 10???????? and the same would go for the maximum????? So maybe its a bit of food for thought for everyone how strongly your opinions are and how quickly new evidence might change your views.

[The PIT]

I think it shows how many 'regional' events take place?

Look at the waters at a glacier snout and you'll see what having a couple of km of ice on top of you will do if you're rock. We're supposed to believe wood ,leather and flax can get dragged along the floor of a glacier and remain intact (only to rot away in days if 'exposed' to the air)???

No they get frozen within the ice and the ice moves or rather flows due to gravity to the lowest point taking what ever is frozen within with it. Yes frozen things don't tend to decay hence you leave certain stuff in your freezer. Ice stops the decay process which resumes when warmed up of course.

Good example of high a Glacier can hide and move fairly large items http://en.wikipedia.org/wiki/Star_Dust_%28aircraft%29

[Gray-Wolf]

Pit , these are hunter gatherers sourcing the carabou/reindeer at the edge of the ice patches where lichen could be accessed through the snow overburden.

Mosquito's crashed on the top of the mountainds are a wholey different kettle of fish (Apples and Pears?) so burried in the 'feed areas' and 'deposits on the ice edge' are seriously different scenarios (unless the game can find fodder over 2 km of ice)

[stewfox]

I thought that I would throw a post in to make everyone think about how strong their views are. I try to remain as open minded as possible but regarding arctic sea ice I have to admit that I think that the 'ice crisis'(or lack of ice) will probably come down to a fuss over nothing. However I do think quite regular what would need to happen in order for me to change my stance on the matter. Personally I think that I would need to see at least 1 year of sub 2007 ice levels along and/or a few other very low ice years close to the 2007 level (mainly referring to the minimums) within the next say 10 years or so (and that is with existing data sources) Remember if you were just talking about average luck over 10 years you would expect to have a minimum year of the chance of 1 in 10???????? and the same would go for the maximum????? So maybe its a bit of food for thought for everyone how strongly your opinions are and how quickly new evidence might change your views.

I assume you mean spectacular rather then regular. ?

We musn't forget the averages especially the mins in the last decade can be misleading. IJIS only has specific detail since 2002

1970s often had min extents bewteen 7million kms to 8million kms. A 30% decrease on that has to be at least 'interesting'

http://en.wikipedia...._ice_extent.svg

We maybe not have another min below 2007 for 2yrs or 50yrs

If we do experience natural background cooling in the next 20yrs that may delay man made warming and the artic demise.

[Yorkshiresnows]

Hi Folks

Here's the weekly Arctic Ice Report from Accu-weather:

http://www.accuweather.com/video/619000794001/monday-morning-sea-ice-report.asp

Seems Joe's pretty confident of a recovery in ice throughout 2011.

Y.S

[stewfox]

C'mon GW, have a punt at the ice extent dates over the coming months! Twould be interesting to have guesses from as many viewpoints as possible.

In need it would.

Is there any data , web site that looks at artic average temps over the winter period how they compare to 30yrs ago etc

[cooling climate]

This is a nice link that shows the ice growth in the last few days.

Use the speed control on the upper right hand side to slow the loop down.

http://arctic.atmos....ic.color.4.html

Edited September 27, 2010 by cooling climate

[sunny starry skies]

<br />Absolutely.<br /><br />Trouble is no one seems able to ascertain how much warmer we should now be by compiling the natural cycles, but minus any CO2 contribution. If we don't know that answer, how can we possibly say how much of the current warming is AGW? <br /><br />I asked (some would say droned on about) how much Arctic ice would/should there be without the influence of AGW, no one seems to be able to answer this. The standard answer is 'we have less now than in the past X amount of years' but that doesn't provide any detail and certainly doesn't answer my question.<br /><br />I don't doubt we've contributed to the warming in recent decades but I want to know how much?<br />

<br /><br /><br />

Hi Jethro, how about in the IPCC AR4 report here:

http://www.ipcc.ch/publications_and_data/ar4/wg1/en/tssts-4-1.html

Without CO2, ocean temps are ~0.5C lower, land temps are ~0.8C lower than with CO2. So Arctic ice should, without anthropogenic CO2, perhaps be approximately where it was at the beginning of the century, the last time global temps were that low, when it took multiple years to traverse either the NWP or the Northeast Passage. Now you can do both in a single season. If the increased solar forcing since the beginning of the century has a disproportionately large effect on Arctic ice, then perhaps it would be comparable to the 1940s-1950s extents, still far higher than today's, and only a little less than at the start of the century.

[jethro]

Hmmmmm.....

"Evidence of the effect of external influences, both anthropogenic and natural, on the climate system has continued to accumulate since the TAR. Model and data improvements, ensemble simulations and improved representations of aerosol and greenhouse gas forcing along with other influences lead to greater confidence that most current models reproduce large-scale forced variability of the atmosphere on decadal and inter-decadal time scales quite well. These advances confirm that past climate variations at large spatial scales have been strongly influenced by external forcings. However, uncertainties still exist in the magnitude and temporal evolution of estimated contributions from individual forcings other than well-mixed greenhouse gases, due, for example, to uncertainties in model responses to forcing. Some potentially important forcings such as black carbon aerosols have not yet been considered in most formal detection and attribution studies. Uncertainties remain in estimates of natural internal climate variability. For example, there are discrepancies between estimates of ocean heat content variability from models and observations, although poor sampling of parts of the world ocean may explain this discrepancy. In addition, internal variability is difficult to estimate from available observational records since these are influenced by external forcing, and because records are not long enough in the case of instrumental data, or precise enough in the case of proxy reconstructions, to provide complete descriptions of variability on decadal and longer time scales"

Black carbon is not considered (more recent research shows this to be very important when considering Arctic melt) they don't know the ocean heat content variability (covers 70% of the surface of the Earth) and there isn't enough information available to estimate external forcing. In fact, the only thing they state with any degree of confidence is forcing from well-mixed greenhouse gases.

I appreciate that the calculations are there for how much CO2 is released annually, the calculations are also there for the theoretical impact this should have, but that doesn't provide real world answers. And with respect, it certainly doesn't provide "Without CO2, ocean temps are ~0.5C lower, land temps are ~0.8C lower than with CO2".

[sunny starry skies]

Without spare Earths on which to run the experiment, the models are the best we have. The contribution from CO2 is ~0.5-0.8C, and there is little reason to suggest it would be different with the additional forcings coded in, seeing as both the 'with' and 'without' model experiments are lacking in the same things. Of course you can always suggest that since there are specific uncertainties we therefore have no idea what is going on, but that would be rather negative, don't you think?

CJWRC, what evidence do you have for thickening ice in the Arctic? Surely you're not using the PIPS 2.0 model where the ice thickness estimates are not validated, and volume estimates by numpties such as steven goddard do not take into account concentration data or the fact that PIPS reports maximum thicknesses (so that subs do not surface under ice too thick...)? The PIPS model is specifically not intended to be a climatologic resource for ice thickness data, whereas the PIOMAS mode validates the PIPS data to come up with realistic volume values. Both, of course, are models, but PIOMAS at least is validated, and shows a rapid decline.

[stewfox]

Artic ice extent up now 406,875 in the last week with a likey revision upwards by the end of the day

Where are we with previous years and end of September increases.

Cf

2009 132,812KMs

2008 251,406KMs

2007 61,875KMs

2006 169,219KMs

2005 179,219KMs

2004 438,125KMs

2003 34,219KMs

2002 Not Available

I appreciate its one set of data we are not comparing like for like , different staring points etc but its real data.

Edited September 28, 2010 by stewfox

[BornFromTheVoid]

In need it would.

Is there any data , web site that looks at artic average temps over the winter period how they compare to 30yrs ago etc

This one might be of some use to you http://www.esrl.noaa.gov/psd/data/composites/day/

Another 50,000km2 increase... for now. That's 6 days with gains >50k, could we equal 2004 which got 8? The IJIS concentration images shows good growth all across the Bering side edge of the ice and into the Canadian Archipelago.

[jethro]

Without spare Earths on which to run the experiment, the models are the best we have. The contribution from CO2 is ~0.5-0.8C, and there is little reason to suggest it would be different with the additional forcings coded in, seeing as both the 'with' and 'without' model experiments are lacking in the same things. Of course you can always suggest that since there are specific uncertainties we therefore have no idea what is going on, but that would be rather negative, don't you think?

Oh I know the models are the best we have but the models have gaping holes in them due to lack of known data, as such the results shouldn't be taken too literally. All too often the model results are seen as providing a view into the future and yes they do, but not as clearly as some would have us believe. What they provide is a canvas from a paint by numbers kit, theoretically you should be able to produce a work of art but it won't be a Constable or Turner, never will be and shouldn't be viewed as such.

Taking the known emission figures and properties of CO2, extrapolating that information into a chaotic system and accepting accuracy from those results may be the best we currently have without the benefit of a spare Earth but that doesn't actually quantify a great deal. That's not negative, it's merely accepting the inherent flaws in our current understanding. Do we have any idea what's going on? Yes, we have some idea. Do we have every answer? No, we do not.

It's not wrong to seek more information and answers, IMO it's hugely positive, not negative.

[Guest mycroft]

talking of properties of C02, can anyone tell me how it increase's ocean temps?

[Devonian]

talking of properties of C02, can anyone tell me how it increase's ocean temps?

Humm. Lets ignore the contentious thing - CO2. Lets instead look at the greenhouse effect and see if I've got this right

Suppose the greenhouse effect was to increase. The lower atmosphere would warm in response? So what would happen to the oceans? Well, they're heated by the Sun, but if the atmosphere is warmer it seems to me they wont loose that energy as fast as before? So they will be warmer? A bit placing identical jugs of water in two identical rooms of different temperature - the jug in the warmer room will end up the warmest.

[NorthNorfolkWeather]

This is a nice link that shows the ice growth in the last few days.

Use the speed control on the upper right hand side to slow the loop down.

http://arctic.atmos....ic.color.4.html

That's a heck of a turn around from a month ago, now seems to be advancing on most fronts

[Gray-Wolf]

I think we could also say that , in a 'greenhouse world' air temps are warmer and so can hold more moisture leading to less clouds leading to more absorbtion of sunlight into the ocean warming it more? Come night fall the same air mass holds less moisture as it cools and forms low level stratoform clouds which then can trap the heat in??

[NorthNorfolkWeather]

I think we could also say that , in a 'greenhouse world' air temps are warmer and so can hold more moisture leading to less clouds leading to more absorbtion of sunlight into the ocean warming it more? Come night fall the same air mass holds less moisture as it cools and forms low level stratoform clouds which then can trap the heat in??

Which actually reinforces my point of a few weeks ago that Black body radiation needs some clear skies.