Arctic ice

[Devonian]

Gray-Wolf,

I, and I'm sure others, don't appreciate that tone ("the likes of Mr S," "cobbling together their disingenuous 'facts'"). Is it unfair to request information sources (which would seem somewhat two-faced considering the frequent calls for skeptics to produce their evidence)?

As for the "dramatic" ice losses last year, it is worth noting that the summer losses were following on from a low winter maximum. This is not a comparison with this year's ice extent - I accept that the multiyear ice levels are probably lower this year than last year despite the overall ice level being higher. If we look back at the ice extent graph posted previously then we can see that although the minimum in 2007 was quite a bit lower than the 1979-2000 average, as was the maximum, the actual rate of decline was not significantly faster (though I will grant that it was a little faster than average).

So although the actual ice extent was particularly low at minimum (as it was at maximum as well), the actual rate of ice loss was not catastrophic.

Sorry, CB, will you please post your souces for the various claims you make in this post (if you get my drift ). I must say I though the graph simply 'fell off a cliff' last summer:

NH Sea ice

Back to this year though, who knows what the future holds in store? So far the rate of decline has exceeded last year's from time to time, but right now we don't seem to be any worse off, in terms of ice extent, than we were last year (and it's already mid-June). How the arctic sea ice will fare over the remainder of the summer is anyone's guess right now and, as has been said oh-so-many times already, only time will tell.

CB

Not long now.

[Gray-Wolf]

I too was a little unsure at how 'un phased' C.Bob was about the unexpected extent of last years melt especially the losses of perennial ice that were involved. It may be that C. Bob does have access to information and data that NSIDC and NASA do not have and is therefore better positioned to play down what, to the rest of us, were unprecedented melt rates through Aug/Sept and the un forcast final ice extent (at it's absolute minimum).

A simple 'Google' on ice extent shows just how, over a very few years, things have rapidly altered with reports from 2002/05 forcasting an ice free summer pole by 2050 (if the ,then, record melt continued at it's, then, rate) to the probability (50/50) of the north pole being ice free this year and the loss of summer ice by 2013.

[Devonian]

I too was a little unsure at how 'un phased' C.Bob was about the unexpected extent of last years melt especially the losses of perennial ice that were involved. It may be that C. Bob does have access to information and data that NSIDC and NASA do not have and is therefore better positioned to play down what, to the rest of us, were unprecedented melt rates through Aug/Sept and the un forcast final ice extent (at it's absolute minimum).

Yup, and that graph I linked to needs to be put into context by viewing it with the figures for changed to MYI and FYI.

Changes to ice age from here.

A simple 'Google' on ice extent shows just how, over a very few years, things have rapidly altered with reports from 2002/05 forcasting an ice free summer pole by 2050 (if the ,then, record melt continued at it's, then, rate) to the probability (50/50) of the north pole being ice free this year and the loss of summer ice by 2013.

Indeed. I don't, though, fwiw, expect the sea ice to be quite so rapid - well, I hope it wont be. This summer will be a big pointer I think, though.

Edited June 17, 2008 by Devonian

[Mr Sleet]

Firstly I will appologise for any offence I may have caused to reader on this thread. I do ,however, find it irksome to find folk who claim to be interested/passionate about a topic not being bothered to put in a little time and effort on their own behalf and crying out to be 'spoonfed' details/data.

If someone has gone to the trouble of rooting out info, and given source names, then surely we can do the rest for ourselves .

As Jethro suggested I shall tone it down.

I appreciate others defending me but I really didn't take offence at GW's post or Devs response which was full of winks etc which tells me where he is coming from.

I'm sure Dev and GW are really nice guys (despite their stance on AGW )

[biffvernon]

Look folks, the New Ice Age is here. The blue line has gone above the green dashy one.

http://nsidc.org/data/seaice_index/images/..._timeseries.png

The deniers are proved right.

[Admiral_Bobski]

Sorry, CB, will you please post your souces for the various claims you make in this post (if you get my drift ). I must say I though the graph simply 'fell off a cliff' last summer:

Various claims? I made one claim, and one claim alone, which was that the decline of ice extent was not catastrophically fast in comparison to the 1979-2000 average according to the graph that everyone else has been looking at. I'll provide the link for it again: http://nsidc.org/data/seaice_index/images/..._timeseries.png (I did say that it was the ice extent graph that we'd been looking at earlier, so I didn't see the need to provide the link again).

I too was a little unsure at how 'un phased' C.Bob was about the unexpected extent of last years melt especially the losses of perennial ice that were involved. It may be that C. Bob does have access to information and data that NSIDC and NASA do not have and is therefore better positioned to play down what, to the rest of us, were unprecedented melt rates through Aug/Sept and the un forcast final ice extent (at it's absolute minimum).

A simple 'Google' on ice extent shows just how, over a very few years, things have rapidly altered with reports from 2002/05 forcasting an ice free summer pole by 2050 (if the ,then, record melt continued at it's, then, rate) to the probability (50/50) of the north pole being ice free this year and the loss of summer ice by 2013.

Hmmm. So much for "toning it down". I found it hard to read the first paragraph until I had scraped the excess sarcasm off it. As I said above, I was referring to the graph that everyone was looking at - the one which biff so succinctly described as the one with the "blue line" and the "green dashy line". I'm not "playing down" anything - I am refraining from playing anything up, though.

Look folks, the New Ice Age is here. The blue line has gone above the green dashy one.

http://nsidc.org/data/seaice_index/images/..._timeseries.png

The deniers are proved right.

Yes, that's the graph I'm talking about. Nice to see some more hilarious pith from Mr Vernon again...

CB

[bluecon]

One overlooked point is, can a couple months of warm summer temperatures overcome the many months of extreme cold in the Arctic last Winter. This could well make the argument of old ice or new ice moot. I have done a little reading on this in the last few days and am coming to the conclusion that the temperature in the Winter is the overiding factor in determining the amount of ice.

And I ordered an old book complete with pictures of Larsen's 1944 journey. The guy was amazing in taking the St. Roch through uncharted waters of the Arctic.

[Devonian]

One overlooked point is, can a couple months of warm summer temperatures overcome the many months of extreme cold in the Arctic last Winter.

Clearly they can - see summer 2007.

This could well make the argument of old ice or new ice moot. I have done a little reading on this in the last few days and am coming to the conclusion that the temperature in the Winter is the overiding factor in determining the amount of ice.

??? Because the ice is colder and takes longer to melt? Can't see it myself. I think it's a minor effect, if an effect at all in the scheme of things.

And I ordered an old book complete with pictures of Larsen's 1944 journey. The guy was amazing in taking the St. Roch through uncharted waters of the Arctic.

Oh, so traversing the NW passage then was unusual? Exactly...

[bluecon]

Oh, so traversing the NW passage then was unusual? Exactly...

Actually if you looked at the factual information Larsen believed he could make it through the NW Passage almost any year in the Thirties and Forties. And proved it with his easy transit in 1944.

Of course it was unusual in that the waters had never had a boat through them before and he had know idea what was in store.

Edited June 17, 2008 by bluecon

[cheeky_monkey]

One overlooked point is, can a couple months of warm summer temperatures overcome the many months of extreme cold in the Arctic last Winter. This could well make the argument of old ice or new ice moot. I have done a little reading on this in the last few days and am coming to the conclusion that the temperature in the Winter is the overiding factor in determining the amount of ice.

i was under the impression it was the other way round?...summer temperatures determine the amount of melt..therefore the the extent of ice that survives to the next winter..a run of cooler than normal summers will result in an increasing amount of ice retained each year?

[bluecon]

i was under the impression it was the other way round?...summer temperatures determine the amount of melt..therefore the the extent of ice that survives to the next winter..a run of cooler than normal summers will result in an increasing amount of ice retained each year?

Ther are several months of cold weather and a few months of warm weather.

Granted the unusual warmth of last summer likely has a large affect.

However I think the severe cold of last winter will overide that.

Latest ice extent.

http://www.socc.ca/seaice/seaice_current_e.cfm

Canadian Archipelego Ice extents(area of the NW Passage) have increased greatly since 1999.

Another fallacy put to rest?

This explains why it was so easy for the St. Roch ll to traverse the passage.

http://www.socc.ca/images/seaice/islands_two.jpg

Edited June 17, 2008 by bluecon

[Gray-Wolf]

When I was looking at the archipelago yesterday the Alaskan end (where the polynya off Banks opened early) was blue water with what I could see of the deep water channel well fragmented with only 1 area of 'blockage'.

Looking back can be useful but keeping current in such a dynamic world surely has it's merits too?

Edited June 18, 2008 by Gray-Wolf

[bluecon]

Snowing in the Arctic again today.

http://www.weatheroffice.gc.ca/jet_stream/index_e.html

[bluecon]

The Europeans sure are'nt very nice to Polar Bears. Second Polar Bear this summer in Europe shot.

just because they like to eat people is no reason to shoot them.

http://www.polarbearsinternational.org/in-...s/wayward-bear/

[acbrixton]

Actually it shows much more sea ice in April 2008 than April 2007 and at least in the Canadian Arctic May 2008 has been colder than 2007. The whole country of Canada has been below normal for temps.

Bluecon, the NSIDC have now updated the graph (see BBC News Online) and as at mid June it is clear that the amount of Arctic sea ice is at a similar level to mid June last year meaning that so far this year there has been an increased melt rate compared to last year. From the graph it is clear that last year the rate of melt increased significantly in the 6 weeks from mid June to late July. It will be interesting to see how things stand at the end of July this year.

So far the data appears to support those who have argued that the colder conditions in the Arctic last winter leading to an increase in both aggregate ice cover and the proportion of single year ice would not prevent a summer loss at least comparable to last year.

regards

ACB

[bluecon]

Bluecon, the NSIDC have now updated the graph (see BBC News Online) and as at mid June it is clear that the amount of Arctic sea ice is at a similar level to mid June last year meaning that so far this year there has been an increased melt rate compared to last year. From the graph it is clear that last year the rate of melt increased significantly in the 6 weeks from mid June to late July. It will be interesting to see how things stand at the end of July this year.

So far the data appears to support those who have argued that the colder conditions in the Arctic last winter leading to an increase in both aggregate ice cover and the proportion of single year ice would not prevent a summer loss at least comparable to last year.

regards

ACB

There was also a period of very unusually high temperatures last year.

Temps are lower than the past.

http://www.worldclimatereport.com/index.ph...-in-the-arctic/

Edited June 19, 2008 by bluecon

[acbrixton]

Quite so. However last summer's warmth acted on an ice pack that had a rather higher proportion of thicker multi-year ice than is present this summer. It would follow, therefore (all other things being equal), first that a repetition of last summer's warmth would lead to a significantly lower minimum this year than last year, secondly that for this year's minimum to equal last year would not require such anomolous warmth.

On the evidence so far it looks highly likely that the minimum will be below that of 2006, the second lowest minimum after 2007, and probable that it will approach that of 2007.

regards

ACB

Not sure that I fully appreciate the point of the link: it cites a study purporting to show through dendrochonology that summers in northern 'Fennoscandia' were warmer than now at four points in the last 1500 years. Those findings may well be credible/academically respectable. However first they cover a small part of Arctic Scandinavia and not the Arctic region as a whole; secondly Arctic Scandinavia is very largely ice-free all year round; thirdly even if the findings were applicable to the entire Arctic region they would be irrelevant to the present discussion as to recent trends in ice minima in general and the prospects for this year in particular.

Edited June 19, 2008 by acbrixton

[Iceberg]

There was not a period of very unusually high temperatures last summer.

The two reasons for the ice melt where increased radiative melting and or increased current strength/temperature.

WRT larsens journey, various people tried and failed to navigate the NW passage in the 30's and 40's. Also there are two passage the narrow and the deep. The narrow opens roughly 10% of the time the deep maybe 2% or 3% of the time and never in successive years(as far as we know!)

[BLAST FROM THE PAST]

Look folks, the New Ice Age is here. The blue line has gone above the green dashy one.

http://nsidc.org/data/seaice_index/images/..._timeseries.png

The deniers are proved right.

That must really bug you

BFTP

[Gray-Wolf]

Not as much as the recent changes bug the Carribou

http://environment.newscientist.com/channe...ble-whammy.html

Ho Hum....

[Mr Sleet]

Bluecon, the NSIDC have now updated the graph (see BBC News Online) and as at mid June it is clear that the amount of Arctic sea ice is at a similar level to mid June last year meaning that so far this year there has been an increased melt rate compared to last year. From the graph it is clear that last year the rate of melt increased significantly in the 6 weeks from mid June to late July. It will be interesting to see how things stand at the end of July this year.

So far the data appears to support those who have argued that the colder conditions in the Arctic last winter leading to an increase in both aggregate ice cover and the proportion of single year ice would not prevent a summer loss at least comparable to last year.

regards

ACB

No, it's clear that there was an increased melt rate for two weeks in April that has brought us to where we are now. For now, the two lines are diverging in favour of a lower melt rate.THis is even clearer from the relevant graphs on the CT site.

Quite so. However last summer's warmth acted on an ice pack that had a rather higher proportion of thicker multi-year ice than is present this summer. It would follow, therefore (all other things being equal), first that a repetition of last summer's warmth would lead to a significantly lower minimum this year than last year, secondly that for this year's minimum to equal last year would not require such anomolous warmth.

On the evidence so far it looks highly likely that the minimum will be below that of 2006, the second lowest minimum after 2007, and probable that it will approach that of 2007.

regards

ACB

Actually at the moment things look much better than in 2006.

Edited June 19, 2008 by Mr Sleet

[Gray-Wolf]

Guy's, we are still not in the 'catastrophic melt' period (July-Sept) so lets not go piffling on about the odd 200,000sq km at this stage of the game!

For me, at least, the real impact to watch is on the remaining perennial ice that was driven into shore, and became fast over winter, at the end of last seasons melt. Seeing as we have suffered a 20% drop in perennial over the past 3 years of melt any more losses are confirmation that the beginning of the end for perennial, and then summer ice, is well underway.

I would expect that ,from this point on, your precious graph to show a close shadowing of last years melt (as it was around now that the 'energy' available up north went into melting vast blocks of 20ft + thick perennial ice and not 2 1/2ft to 4ft single year) for 4 or so weeks and then, as the perennial in the shallows disappears (off Siberia/Canadian archipelago) the thin skin of remnant single year ice will be allowed allowed to follow the prevailing winds/currents and rapidly fail leading to a 'final spurt' from this years plot overtaking last years incredible ice min. extent.

Edited June 19, 2008 by Gray-Wolf

[bluecon]

There was not a period of very unusually high temperatures last summer.

The two reasons for the ice melt where increased radiative melting and or increased current strength/temperature.

WRT larsens journey, various people tried and failed to navigate the NW passage in the 30's and 40's. Also there are two passage the narrow and the deep. The narrow opens roughly 10% of the time the deep maybe 2% or 3% of the time and never in successive years(as far as we know!)

Yes there was a long period of record temps.

"Record 22C temperatures in Arctic heatwave

Parts of the Arctic have experienced an unprecedented heatwave this summer, with one research station in the Canadian High Arctic recording temperatures above 20C, about 15C higher than the long-term average. The high temperatures were accompanied by a dramatic melting of Arctic sea ice in September to the lowest levels ever recorded, a further indication of how sensitive this region of the world is to global warming. Scientists from Queen's University in Ontario watched with amazement as their thermometers touched 22C during their July field expedition at the High Arctic camp on Melville Island, usually one of the coldest places in North America.

"This was exceptional for a place where the normal average temperatures are about 5C. This year we frequently recorded daytime temperatures of between 10C and 15C and on some days it went as high as 22C," said Scott Lamoureux, a professor of geography at Queen's.

"Even temperatures of 15C are higher than we'd expect and yet we recorded them for between 10 and 12 days during July. We won't know the August and September recordings until next year when we go back there but it appears the region has continued to be warm through the summer.""

http://www.independent.co.uk/environment/c...ave-394196.html

Larsen is on record of having said he could cruise through the passage most any year in the 30's and 40's when he was in the Arctic for years at a time.

You have no idea how often the passage was open in the past. This is only a partial list and the 5th boat in history quote is not accurate. Many more boats have gone through the passage in a single season.

1940-1944 ..... The 'St Roch', a Royal Canadian Mounted Police vessel became the first vessel to complete the passage in one season and the first vessel to pass through both ways.

*1969 ..... Exxon's specially modified oil tanker, the 'Manhattan' became the first commercial vessel to transit the passage. Accompanied by two ice breakers and at a cost of ten's of millions of dollars it symbolically took on one barrel of oil. As of 2004 it remains the only commercial vessel to make the passage.

*1977 ..... The Belgian, Willie de Roos, sailing his 44 ft steel sailboat became the first sailboat to transit the passage and completing the voyage in one season.

*1995 .... 'Dove' a 27ft steel sailboat, built and skippered by Winston Bushnell and with two friends as crew also completed the voyage in one season becoming the fifth boat in history to do so.

*2003 .... On the 100th anniversary of 'Gjoa' first ever transit seven vessels attempted the passage. Two made it through successfully. Three were caught in the ice where they have been for the past 10 months. The remaining two we haven't yet been able to track down.

http://www.theoceans.net/story/NorthwestPa...eApr72005.shtml

Edited June 19, 2008 by bluecon

[Thundery wintry showers]

There was not a period of very unusually high temperatures last summer.

The two reasons for the ice melt where increased radiative melting and or increased current strength/temperature.

WRT larsens journey, various people tried and failed to navigate the NW passage in the 30's and 40's. Also there are two passage the narrow and the deep. The narrow opens roughly 10% of the time the deep maybe 2% or 3% of the time and never in successive years(as far as we know!)

I don't think temperatures were that unusually high, but there was an unusual preponderance of high pressure leading to lots of dry sunny weather- warm dry sunny summers have long been associated with the decline of ice masses. Plus, the melt was especially rapid around early July when a plume of 10-15C 850hPa air invaded most of Siberia.

However, yes, the two reasons you give are the main causes of the ice melt.

As for the NW passage, I think it was possibly mentioned in one of Devonian's earlier posts, the fact that the passage was possible earlier didn't necessarily mean that it was completely open. Rather, it could have been partially clear of ice, where voyagers fought through what ice there was.

[bluecon]

Compare ice cover 2007 to 2008

http://igloo.atmos.uiuc.edu/cgi-bin/test/p...=18&sy=2008