General Climate Change

[sunny starry skies]

Blimey, what a mess. P.P. - you're obfuscating big-time when you suggest there's no good data on Arctic sea ice. We have dramatic reductions in extent and volume. As G-W has pointed out, there's no indication that such reductions have happened in the last several thousand years. Here, I think, evidence such as small Canadian Arctic ice caps that are exposing rock only last uncovered thousands of years ago helps.

Y.S., you've banged on about Greenland too much for me. There is absolutely no evidence that ice covers what were occupied settlements in Norse Greenland. If you think that, you're sorely deluded. The settlements remain, often with upstanding remains of walls and field systems. The climate back in Norse times, as now, was sufficiently good for them to keep cows and grow enough fodder for the winter. The Little Ice Age did not have the power expand the glaciers and ice sheet outlets into areas where people lived. Climate, contrary to popular belief, but not contrary to the latest science, may not have been the thing that wiped out the Norse - other reasonable explanations include the changing economy of the time and invasion of territory by Thule Inuit. The only destruction of settlements since then is likely to be from sea level rise, which has been considerable in this area.

So Jethro, You've laid your argument out bare - yet there are still flaws in it. You're still after numbers which are not necessary. The article quotes, correctly, a volume of decline since the 1970s. This is based on whole-basin data and is reliable. The next statement saying this cannot be natural variation is what you don't like. High-lattude insolation should be driving to more extensive sea ice (if imperceptibly gradually at the present). Solar variations have flatlined (and recently declined) since the 1970s. Internal variations may contribute some of the change (such as winds helping the 2007 minimum be even lower than it would have been), but not a progressive collapse in thickness and extent. If they could do that, we'd expect to see evidence of such large variations within the age of exploration of the Arctic. We don't. Additionally, there's an excellent correlation between Arctic air temperature and sea ice loss - suggesting the driver is in the air, not the sea (my apologies - I looked at the graphs yesterday, but can't find wher they are). Air temperature rise in the Arctic is attributed to humans, and so sea ice loss is most likely driven by the same cause. The article is saying that there is no driver of Arctic sea ice that can be driving the progressive decline in area and volume. Oh, C-Bob, you can add Richard Alley (among hundreds of others) to your list of people that disagree with you on orbital forcing. And one paper suggesting an alternative is not exactly upsetting the applecart on that, rather irrelevant, score.

Interesting graph this - shows how we have 20 yeas of relative stability with perhaps a slight decline, followed by a rapid decline in this decade, and the emergence in the last few years of an annual signal in the ice anomaly. This being anomaly and not extent, indicates that the winter allows a refreeze that is comparable in most years (anomaly closer to 0), then a summer collapse that is dramatically lower than previous years as the ice is so thin that it is easily melted out.

Ice volume, just in case anyone's in any doubt, or has had the misfortune to read (yet) another cooked post at WUWT, is on a steep progressive downward slide.

sss

Pete, yup, that was as usual, supposition!

Edited June 2, 2010 by sunny starry skies

[Guest North Sea Snow Convection]

Hi,

For me it really does come down to clouds and water vapour (and the effect that known natural cycles can have on them) and I would personally recommend anybody who is interested in climate change to view the Peter Taylor conference video (never mind the book ... which is excellent), which mirrors my own concerns over the computer modelling projections of what our future holds.

Y.S

Yes, I think that is right. The assumption made of positive feedbacks being present in clouds and water vapour accounts for up to 75% of the projected warming suggested as generated amprophomorphically (spelling? lol!). That raises the stakes in terms of the AGW suppositions that are being made if doubt continues to increase over this matter. Research as you will know, and quite rightly keep pointing out to the regulars on the other side of the debate, suggests that conversely negative (cooling) feedbacks may be present instead within the interactions here, which means that no matter how much CO'2 /GHG input there is, then any 'heat' is simply lost into space and net cooling can occur instead as opposite effects to 'heat trapping' occur. Research is still ongoing and will in time I think put a spanner in the theory at least in terms of how overstated the impact of AGW is. This, herein, pertains to the concerns that the likes of you, I and others have about the computer projections modelled which rely so heavily on this raft of positive feedbacks being reality (instead of mere supposition) and realising the heat 'potential' of CO2/emissions.

At the same time, further solar research and predictions that Landscheidt (primarily) undertook will, imo, be shown to prophetic.

Edited June 2, 2010 by North Sea Snow Convection

[Admiral_Bobski]

Oh, C-Bob, you can add Richard Alley (among hundreds of others) to your list of people that disagree with you on orbital forcing. And one paper suggesting an alternative is not exactly upsetting the applecart on that, rather irrelevant, score.

So that's the best you can come up with? I think you'll find - if you looked, or if you even cared - that there are more papers "suggesting an alternative" than there are suggesting we should be on a downward slide into an orbital-forcing induced ice age. But the idea that orbital forcing is past its maximum is a very convenient one for pinning the blame on AGW, isn't it?

I have shown that orbital forcing is a non-issue since it is not past its maximum effect, but rather than debate that issue you just spout out another name that agrees with your viewpoint over mine. Well, Big Wows there, glad you pointed it out, obviously my entire worldview has been destroyed by your clever debating skills.

Richard Alley disagrees with me?

So what?

CB

[Yorkshiresnows]

Blimey, what a mess. P.P. - you're obfuscating big-time when you suggest there's no good data on Arctic sea ice. We have dramatic reductions in extent and volume. As G-W has pointed out, there's no indication that such reductions have happened in the last several thousand years. Here, I think, evidence such as small Canadian Arctic ice caps that are exposing rock only last uncovered thousands of years ago helps.

Y.S., you've banged on about Greenland too much for me. There is absolutely no evidence that ice covers what were occupied settlements in Norse Greenland. If you think that, you're sorely deluded. The settlements remain, often with upstanding remains of walls and field systems. The climate back in Norse times, as now, was sufficiently good for them to keep cows and grow enough fodder for the winter. The Little Ice Age did not have the power expand the glaciers and ice sheet outlets into areas where people lived. Climate, contrary to popular belief, but not contrary to the latest science, may not have been the thing that wiped out the Norse - other reasonable explanations include the changing economy of the time and invasion of territory by Thule Inuit. The only destruction of settlements since then is likely to be from sea level rise, which has been considerable in this area.

So Jethro, You've laid your argument out bare - yet there are still flaws in it. You're still after numbers which are not necessary. The article quotes, correctly, a volume of decline since the 1970s. This is based on whole-basin data and is reliable. The next statement saying this cannot be natural variation is what you don't like. High-lattude insolation should be driving to more extensive sea ice (if imperceptibly gradually at the present). Solar variations have flatlined (and recently declined) since the 1970s. Internal variations may contribute some of the change (such as winds helping the 2007 minimum be even lower than it would have been), but not a progressive collapse in thickness and extent. If they could do that, we'd expect to see evidence of such large variations within the age of exploration of the Arctic. We don't. Additionally, there's an excellent correlation between Arctic air temperature and sea ice loss - suggesting the driver is in the air, not the sea (my apologies - I looked at the graphs yesterday, but can't find wher they are). Air temperature rise in the Arctic is attributed to humans, and so sea ice loss is most likely driven by the same cause. The article is saying that there is no driver of Arctic sea ice that can be driving the progressive decline in area and volume. Oh, C-Bob, you can add Richard Alley (among hundreds of others) to your list of people that disagree with you on orbital forcing. And one paper suggesting an alternative is not exactly upsetting the applecart on that, rather irrelevant, score.

Interesting graph this - shows how we have 20 yeas of relative stability with perhaps a slight decline, followed by a rapid decline in this decade, and the emergence in the last few years of an annual signal in the ice anomaly. This being anomaly and not extent, indicates that the winter allows a refreeze that is comparable in most years (anomaly closer to 0), then a summer collapse that is dramatically lower than previous years as the ice is so thin that it is easily melted out.

Ice volume, just in case anyone's in any doubt, or has had the misfortune to read (yet) another cooked post at WUWT, is on a steep progressive downward slide.

sss

Pete, yup, that was as usual, supposition!

Hi Sunny skies,

Sorry to have banged on about the Greenland settlements ...... !!!!

The Vikings left .... because the climate changed and they were beginning to die out .... it was abandoned because it had to be.

They farmed, they had cattle, they fished (without fear of Icebergs) and they prospered. Its a valid point and there are several books that list all of the historical records of this and indeed other Northern European farming trends over this period.

All of them (say this again, all of them) show or illustrate a warmer period with less ice around.

So, I'll continue to bang on around this ... as it is a relevant point. Another fact is that you are not able to state with any certainty that the Ice levels we are seeing in the arctic region now are unprecedented as there is no absolute data to prove this one way or the other, just proxy data and historical records of farming that would indicate that there were warmer and colder periods over the past 1000 years.

Y.S

Yes, I think that is right. The assumption made of positive feedbacks being present in clouds and water vapour accounts for up to 75% of the projected warming suggested as generated amprophomorphically (spelling? lol!). That raises the stakes in terms of the AGW suppositions that are being made if doubt continues to increase over this matter. Research as you will know, and quite rightly keep pointing out to the regulars on the other side of the debate, suggests that conversely negative (cooling) feedbacks may be present instead within the interactions here, which means that no matter how much CO'2 /GHG input there is, then any 'heat' is simply lost into space and net cooling can occur instead as opposite effects to 'heat trapping' occur. Research is still ongoing and will in time I think put a spanner in the theory at least in terms of how overstated the impact of AGW is. This, herein, pertains to the concerns that the likes of you, I and others have about the computer projections modelled which rely so heavily on this raft of positive feedbacks being reality (instead of mere supposition) and realising the heat 'potential' of CO2/emissions.

At the same time, further solar research and predictions that Landscheidt (primarily) undertook will, imo, be shown to prophetic.

Nice Post

Y.S

[Devonian]

Hi Sunny skies,

Sorry to have banged on about the Greenland settlements ...... !!!!

The Vikings left .... because the climate changed and they were beginning to die out .... it was abandoned because it had to be.

They farmed, they had cattle, they fished (without fear of Icebergs) and they prospered.

The archaelogical evidence (see work by Jared Diamond) is the Greenlanders ate remarkably little fish. The reason for this is unknown but the evidence (or lack of remains of eated cooked fish in rubbih tips and exceervations) is, aiui, pretty strong. They did catch seals though and poor weather could restrict that harvest. Whatever, life for Greenlanders was tough and they did very well to survive as long as they did.

Not sure where you get the idea there were no icebergs from?

Its a valid point and there are several books that list all of the historical records of this and indeed other Northern European farming trends over this period.

All of them (say this again, all of them) show or illustrate a warmer period with less ice around.

So, I'll continue to bang on around this ... as it is a relevant point. Another fact is that you are not able to state with any certainty that the Ice levels we are seeing in the arctic region now are unprecedented as there is no absolute data to prove this one way or the other, just proxy data and historical records of farming that would indicate that there were warmer and colder periods over the past 1000 years.

Y.S

But you have to make a like for like comparison. Greenlanders arriving in a untouched country would have untouched soil which, for a while, served them very well. But, they did damage their environment and that was a factor in their demise. It's not that weather or climate didn't play a role, just that it wasn't the only reason they died out.

Edited June 2, 2010 by Devonian

[Yorkshiresnows]

The archaelogical evidence (see work by Jared Diamond) is the Greenlanders ate remarkably little fish. The reason for this is unknown but the evidence (or lack of remains of eated cooked fish in rubbih tips and exceervations) is, aiui, pretty strong. They did catch seals though and poor weather could restrict that harvest. Whatever, life for Greenlanders was tough and they did very well to survive as long as they did.

Not sure where you get the idea there were no icebergs from?

But you have to make a like for like comparison. Greenlanders arriving in a untouched country would have untouched soil which, for a while, served them very well. But, they did damage their environment and that was a factor in their demise. It's not that weather or climate didn't play a role, just that it wasn't the only reason they died out.

Oh come off it.

Historical data shows there was less ice and a warmer climate. There is no controversy in this area at all.

Are you saying that conditions then, were likely as warm as now ...... just with less ice !!!!!

The bit about less icebergs his taken from literature and relates to the how Viking fishermen (cod fishing) were able to roam the waters around Greenland and Iceland easily until winter conditions worsened considerably.

The POINT OF ALL OF THIS was to state that if an area that is covered with Ice and inhospitable now, was not covered in ice and was hospitable before ..... would perhaps illustrate that a lot of the proxy data for the medieval warm period ...... was correct (evidence sort of mounts up) and people cannot therefore state with absolute certainty that the arctic area has never been in such a state as now.

This seems a reasonable argument to me. Do google search Amazon and find the book 'The Little Ice Age'. You can look through the pages on line. Its a historical record and does not make any claims for any theory or anything, more a weather and agricultural history of Northern Europe.

Y.S

[jethro]

So Jethro, You've laid your argument out bare - yet there are still flaws in it. You're still after numbers which are not necessary. The article quotes, correctly, a volume of decline since the 1970s. This is based on whole-basin data and is reliable. The next statement saying this cannot be natural variation is what you don't like. High-lattude insolation should be driving to more extensive sea ice (if imperceptibly gradually at the present). Solar variations have flatlined (and recently declined) since the 1970s. Internal variations may contribute some of the change (such as winds helping the 2007 minimum be even lower than it would have been), but not a progressive collapse in thickness and extent. If they could do that, we'd expect to see evidence of such large variations within the age of exploration of the Arctic. We don't. Additionally, there's an excellent correlation between Arctic air temperature and sea ice loss - suggesting the driver is in the air, not the sea (my apologies - I looked at the graphs yesterday, but can't find wher they are). Air temperature rise in the Arctic is attributed to humans, and so sea ice loss is most likely driven by the same cause. The article is saying that there is no driver of Arctic sea ice that can be driving the progressive decline in area and volume. Oh, C-Bob, you can add Richard Alley (among hundreds of others) to your list of people that disagree with you on orbital forcing. And one paper suggesting an alternative is not exactly upsetting the applecart on that, rather irrelevant, score.

You're still not getting it SSS and to be honest, I'm beginning to wonder if it's a deliberate ploy.

This isn't a question of me not liking anything, I've already made it absolutely clear that I accept their findings, I do not doubt that AGW is happening, I am not laying out a sceptic argument (with or without flaws) to counter AGW. Taking a 'one size fits all' approach to answer any questions on here seems to be clouding your responses, leading to a "counter the sceptics" reply.

I'll repeat my question yet again, (given all the research that has been done, this should be available) how much ice should there be if AGW were not happening? And SSS, numbers are necessary, no matter how vague otherwise we are simply back to the ice is melting, there is less ice - that is supposition.

[Devonian]

Oh come off it.

Historical data shows there was less ice and a warmer climate. There is no controversy in this area at all.

I'm sorry but dismissing other people posts doesn't make you right. But, yes, maybe less ice, but your claim was 'they fished (without fear of icebergs' implying no ice, not less ice.

Are you saying that conditions then, were likely as warm as now ...... just with less ice !!!!!

No, I'm asking you what your evidence of less ice is.

The bit about less icebergs his taken from literature and relates to the how Viking fishermen (cod fishing) were able to roam the waters around Greenland and Iceland easily until winter conditions worsened considerably.

Again, the evidence I've read is that the Greenlanders ate remarkably little fish. But, hey, just dismiss it eh? The summer is normally ice free around Greenland.

The POINT OF ALL OF THIS was to state that if an area that is covered with Ice and inhospitable now, was not covered in ice and was hospitable before ..... would perhaps illustrate that a lot of the proxy data for the medieval warm period ...... was correct (evidence sort of mounts up) and people cannot therefore state with absolute certainty that the arctic area has never been in such a state as now.

No one states with absolute certainty aboue the state of the Arctic now - well, you tend to be a bit dismissive of other views I guess...

This seems a reasonable argument to me. Do google search Amazon and find the book 'The Little Ice Age'. You can look through the pages on line. Its a historical record and does not make any claims for any theory or anything, more a weather and agricultural history of Northern Europe.

Y.S

YS, as I say the waters around the part of Greenland inhabited by Norsemen is ice free in the summer now, and, afaik, normally is.

You're still not getting it SSS and to be honest, I'm beginning to wonder if it's a deliberate ploy.

This isn't a question of me not liking anything, I've already made it absolutely clear that I accept their findings, I do not doubt that AGW is happening, I am not laying out a sceptic argument (with or without flaws) to counter AGW. Taking a 'one size fits all' approach to answer any questions on here seems to be clouding your responses, leading to a "counter the sceptics" reply.

I'll repeat my question yet again, (given all the research that has been done, this should be available) how much ice should there be if AGW were not happening? And SSS, numbers are necessary, no matter how vague otherwise we are simply back to the ice is melting, there is less ice - that is supposition.

Jethro, what level of accuracy about past ice areas/conc/extent are you expecting?

Edited June 2, 2010 by Devonian

[jethro]

I'm not expecting anything connected with the past at all, I'm wanting someone, somewhere to come up with some idea of how much ice there should currently be without the influence of AGW.

[Devonian]

I'm not expecting anything connected with the past at all, I'm wanting someone, somewhere to come up with some idea of how much ice there should currently be without the influence of AGW.

Ahh, OK, my bad.

If you look at the CT site the graph trundles along pretty level until around 1950. So, something like, that level seems a possible answer to me, or a reasonable place to start.

Edited June 2, 2010 by Devonian

[sunny starry skies]

YS, NSSC and Dev, I've worked with the original researchers on this one (Greenland), and there is no evidence to demonstrate (a) significant environmental degradation (in fact there is evidence for the opposite), or ( elimination due purely to climate. That was an out-dated idea which Diamond included in his book. More recent research shows this not to be the case. For example, homefields in Greenland were manured (improved) so as to be more productive - they are still visible, and some are used today. The land did not become "inhospitable" in the LIA - less productive may be a better phrase, with the adaptation being to take more seals, but the diet was not exclusively marine even at the end. There is no historical evidence to show "no ice" like you suggest Y.S. (if there is, I'd love to see it, as would many of my colleagues!). The diet of the Norse had little fish (you're right Dev), and had progressively more and more seals into the early LIA. Many of the seals were the Harp seals, which follow the drift ice in early summer. Oddly enough, Harp seals made up 40% of the seal catch as recorded in middens in the earliest pahse from Brattahlid, and >30% of seal bones in all sites in all periods since 1000 AD, indicating that far from there being "no ice" there was indeed sea ice present. This is one of many lines of evidence to show that ice conditions in the MWP in Greenland were likely to be at least comparable to today, and my guess based on the Eastern Settlement data is probably with more ice.

Here's a sample reference on seals:

http://www.nabohome.org/publications/labreports/Norsec34BrattahlidGreenland05.pdf

Y.S., exactly what areas (settlements??) are covered by ice now that weren't in the MWP? If you can't provide some hard evidence I don't believe you.

You do also appreciate that the MWP is very pronounced in Greenland and NW Europe, but that Greenland/NW Europe is not the world (Jean Grove's "The Little Ice Age" is an excellent book BTW)? And what does a warm MWP in Greenland/NW Europe tell you about conditions in Asia, Africa, the Pacific, America? Not much...

Just like a cold winter in Europe, USA doesn't cover the fact that it was the warmest winter globally...

Jethro, why don't you ask the original authors if you're that concerned? [and in case you think otherwise, I'm not suggesting you have strong opinions on their conclusions BTW] I think it's an irrelevant point, as Arctic sea ice change is merely seen as a response to greenhouse forcing, and therefore certainly is not a fundamental pillar of the science. The retreat was predicted and is one of many predictions to come true, as shown by 30 years of detailed data and scattered older data. It is doing exactly as predicted. It may have retreated at some stage in the distant past, but so far as modern Arctic exploration and monitoring goes, the retreat is unprecedented. Graphs reconstructed back to early this century show only a little more ice than in the 1970s/80s, and so if you want my guess, then that should be your non-AGW baseline. But whether it is unprecedented or not, does not matter (not to me, anyway).

NSSC, your post is pure speculation, at odds with the physics of CO2 and our observations of the atmosphere (you do know the greenhouse effect has been observed?). As for water vapour, I'd like to know how you think there wouldn't be more water vapour in a warmer atmosphere!

http://www.skepticalscience.com/water-vapor-greenhouse-gas.htm

sss

[Admiral_Bobski]

I think it's an irrelevant point, as Arctic sea ice change is merely seen as a response to greenhouse forcing, and therefore certainly is not a fundamental pillar of the science.

Why do some on here seem to think that every question is intended to completely destabilise or demolish AGW? Can't someone ask an honest question and expect an honest answer?

And on a note more relevant to me, no comment on the Milankovitch cycles, or is it just to be ignored again?

CB

[Devonian]

YS, NSSC and Dev, I've worked with the original researchers on this one (Greenland), and there is no evidence to demonstrate (a) significant environmental degradation (in fact there is evidence for the opposite), or (B) elimination due purely to climate.

...

Fair enough! But, presumably, they did clear 'trees' and soil was lost as described by Diamond but replaced faster than it was lost? And is the end of the Greenlanders as speculated upon by Diamond (if I remember correctly perhaps a run of poor summers, perhaps ice preventing harp seal hunts) still thought possible?

[jethro]

Jethro, why don't you ask the original authors if you're that concerned? [and in case you think otherwise, I'm not suggesting you have strong opinions on their conclusions BTW] I think it's an irrelevant point, as Arctic sea ice change is merely seen as a response to greenhouse forcing, and therefore certainly is not a fundamental pillar of the science. The retreat was predicted and is one of many predictions to come true, as shown by 30 years of detailed data and scattered older data. It is doing exactly as predicted. It may have retreated at some stage in the distant past, but so far as modern Arctic exploration and monitoring goes, the retreat is unprecedented. Graphs reconstructed back to early this century show only a little more ice than in the 1970s/80s, and so if you want my guess, then that should be your non-AGW baseline. But whether it is unprecedented or not, does not matter (not to me, anyway).

NSSC, your post is pure speculation, at odds with the physics of CO2 and our observations of the atmosphere (you do know the greenhouse effect has been observed?). As for water vapour, I'd like to know how you think there wouldn't be more water vapour in a warmer atmosphere!

http://www.skeptical...enhouse-gas.htm

sss

I'm curious SSS, not concerned - like I said, I'm not viewing this from an 'AGW is wrong' perspective.

I really cannot see how you can say whether or not it's unprecedented does not matter, I'd say it's fairly fundamental. The retreat may have been predicted but taking the last 30 years as evidence of the prediction being accurate is spurious, even without AGW the positive phase of the ocean cycles would have resulted in less ice than the previous 30 odd year negative phase - ice levels were rather high in the 1970's & '80's.

I am rather disappointed that no one seems to have an idea of the size of a non AGW influenced ice pack (I've Googled and cannot find anything either). Strikes me that the state of play is that the ice is at this point in time, less than in recorded history (since 1979 so rather meaningless) possibly less than at any time in history but we're not sure of that fact and even if that's so, we've no idea of how much less.

Guess I'll be keeping that cynic hat on a bit longer....

Dev: Thanks for the straight answer, much appreciated.

[Gray-Wolf]

A bit of 'Easter Islanding' then? With only dwarf trees at their disposal how did they maintain their longships? How long before they've lost all their critters and cannot replace them due to being stranded? One bad winter (we get bad winters even when global temps are breaking records) and you're done for .The tales of blue eyed Inuit from the far NW of Greenland seem to make more sense eh?

Jethro. Before you get a seasonal pack you need to destroy the perennial ice.We have seen the perennial pack slimming down since the first nuke subs went under it (nearly 60 yrs?) and it is a steady decline that accelerated dramatically once a certain 'point' was crossed.

Ice extent will always vary ( look at this winters 'max' and tell me that it was meaningful) but the thing that keeps perennial ice in the Arctic is 'perennial ice'.

Some of that ice was immense (I'll let you google the stats as I know you'll finds them) and so it's loss takes an awful lot of melting.......60yrs and more it would seem.

The open waters that now give us 'records' of ice free conditions (across the whole basin) do not exist, prior to this, for many tens of thousands of years ( as our current records show) so we know that first you need to loose the perennial and then you can get the whole basin ice free. Over the glacial period 'natural conditions' alone have not been up to the job.

So what melted the perennial beyond it's point of no return over that 60+ year period??

Edited June 2, 2010 by Gray-Wolf

[jethro]

Forgive me GW but I'm really beginning to wonder if I'm talking in some unknown language here. How many more times can I say I'm not doubting the findings of that report. Neither am I questioning AGW, our influence upon climate or offering any kind of sceptic argument. I'm simply wanting to know how much ice SHOULD be there without the influence of AGW.

Why is this so difficult?

One point I will disagree with though....evidence for the perennial having reached a point of no return please. That's another large dose of supposition.

[Hiya]

The only destruction of settlements since then is likely to be from sea level rise, which has been considerable in this area.

What do you think the magnitude of these local sea rises were?

[Guest North Sea Snow Convection]

You're still not getting it SSS and to be honest, I'm beginning to wonder if it's a deliberate ploy.

This isn't a question of me not liking anything, I've already made it absolutely clear that I accept their findings, I do not doubt that AGW is happening, I am not laying out a sceptic argument (with or without flaws) to counter AGW. Taking a 'one size fits all' approach to answer any questions on here seems to be clouding your responses, leading to a "counter the sceptics" reply.

I'll repeat my question yet again, (given all the research that has been done, this should be available) how much ice should there be if AGW were not happening? And SSS, numbers are necessary, no matter how vague otherwise we are simply back to the ice is melting, there is less ice - that is supposition.

You may forget but you did actually declare yourself a sceptic shortly before becoming a moderator.

Of course, in that time also, you never totally dismissed AGW as having no effect whatsoever (and neither have I - albeit in my case I think it is very very small and grossly overstated in terms of projections) but there is no doubt that you are now far less sceptic than a year ago.

Just an observation - and you are entitled to amend your position as time moves on

[Gray-Wolf]

Forgive me GW but I'm really beginning to wonder if I'm talking in some unknown language here. How many more times can I say I'm not doubting the findings of that report. Neither am I questioning AGW, our influence upon climate or offering any kind of sceptic argument. I'm simply wanting to know how much ice SHOULD be there without the influence of AGW.

Why is this so difficult?

One point I will disagree with though....evidence for the perennial having reached a point of no return please. That's another large dose of supposition.

Do you not see that the "Above this is not natural" line is the loss of the perennial? Even in 84' there was still enough perennial (in mass) to keep the Arctic locked up in the Arctic (no ice arch failures then!) but these days we have both Fram and Nares bleeding ice all winter long (and lots of that 'so called' perennial [3yr ice with all it's salt and little substance]).

The line is too little perennial to have a pack that does not continue to decline even in 'average years'. The continued decline in ice volume and thickness anoms does homage to the fact that it is 'beyond the point of no return' i.e. 'natural feedback ' systems will conspire to keep the pack seasonal until such time as an ice age allows the re-formation of the depth of halocline needed to keep ice frozen 15m below sea level .

From the data we have amassed my best 'guess' is a pack that is 40% or more 'old style perennial' (glacial ice with a multiyear snow cap). We are well below half of that amount and history will judge my 'guess'........ (though a self educated one if you look at the stats!).

[jethro]

You may forget but you did actually declare yourself a sceptic shortly before becoming a moderator.

Of course, in that time also, you never totally dismissed AGW as having no effect whatsoever (and neither have I - albeit in my case I think it is very very small and grossly overstated in terms of projections) but there is no doubt that you are now far less sceptic than a year ago.

Just an observation - and you are entitled to amend your position as time moves on

I'm sorry NSSC but you are incorrect. I have clearly clarified my views at least twice on this forum, along with many others, in two dedicated threads.

The first of these obviously offers more scope for detail, in which I leave the option to others to pigeon hole me, personally preferring the tag of "questioner".

As far as this particular point in time and my recent posts I have had difficulties trying to make folk understand I am asking this question not from a sceptic viewpoint but from a searching for information point. I have stipulated this as the replies I was receiving were all aimed at beating the sceptic's views rather than answering my question.

When it comes to sceptic/pro/denier and all the other daft tags people get afflicted with, I've always argued for no definitions as to my mind, they all lead to needless and pointless conflict. There are no sides or camps in this debate for me, we're all just individuals with a mutual interest in the climate and future of this planet; to me that seems we all have more in common with each other than the sometimes petty tit for tat would lead folk to believe. If we didn't all share a mutual concern for this planet, we wouldn't be here and that to me is cause for celebration and hope.

Have I amended my position? Well having read through "My stance" written on here back in February 2008 I have to say no, I haven't. I was a questioner then, I'm a questioner now; as you can see I've spent the last however many days asking questions.

Has being a Moderator changed my views? No it hasn't. Being a Moderator simply means assisting everyone to get their chance to have their say, without the fear of intimidation and trying to ensure the debates remain polite and respectful. If someone doesn't comply with that, regardless of their views on this subject, I'll step in. Equally, just because I may fundamentally agree with the gist of someone's argument doesn't mean I'll stand back and let them make it in a rude and hostile manner. Can't get more even handed than that, can I?

GW: you still seem to be approaching this from a "convincing me we're to blame" point of view. I really cannot say any clearer than I've already said that, that is not my approach to this question. I'm not questioning the validity of the AGW theory.

[sunny starry skies]

Hi Jethro, I'll have one last 'go' at your question. How much ice should be up there without AGW? It's a hypothetical question, as we don't have a world without AGW to experiment on, but here's my shot. My guess is as I put in my last reply, a bit more than was observed in the 1950s/1960s/1970s, and a good healthy dose of thick perennial ice that keeps the overall area of pack ice stable (by virtue of not allowing large amounts of open water to appear and trigger the dark water positive feedback). G-W's last post was an excellent description of that. My basis for that assessment - the forcing attribution studies would have a contribution of something like 0.2/0.3C to early 20th Century warming from solar activity. We should assume ENSO (as directionless) and volcanic to be as they were, and so the 0.2/0.3C forcing is all we'd have without AGW. Solar activity stabilised from the 1950s and has slightly declined towards present, but assume it's approximately where it was. There's no historical/empirical evidence of any internal oscillation large enough to remove the old perennial ice and therefore destabilise the multiyear pack. And so my guess is that to determine how much Arctic ice there should be without AGW, take the mid-20th Century values, and maybe add a small amount. That's essentially the whole Arctic basin covered with a decent proportion of thick multiyear ice. Ice outside the basin is easily prone to large fluctuations as it is much more mobile. How's that for my best guess, J?

Hiya - I'm not sure of the numbers off the top of my head, but I think you're looking at as much as 50m in some of the fjords - enough to eliminate some very low coastal sites. There'll be papers around somewhere, and I may be well off with my estimate. Though my feeling is that there would be few settlements right at the coastline due to the mini-tsunami risk from passing icebergs.

See this: http://www.geus.dk/publications/bull/nr14/nr14_p26-49_A1b.pdf - p46 for sea level near Disko Bay (north of the settlements). Also interesting to show ice advances since the MWP - much as in Iceland and Norway, you're generally looking at most at 1-2km laterally.

G-W and Dev - for boats, they could go to 'Markland' (Labrador) for boat-building-sized trees, as well as having some supply from driftwood, and until near the end there were strong trade links with the rest of Europe (walrus ivory). In that way it's not like Easter Island at all. One bad winter doesn't wipe out a settlement - remember where these people came from (Iceland and Norway), and they have shown remarkable ability to adapt. Were one (or a few) bad winters enough to wipe them out they would certainly not have lasted 450 years. That's nearly as long as the time since Columbus! Longer/colder winters quite probably drove them to more heavily utilise the more secure food source of seals, but there's little reason to suggest it killed them (Diamond was speculating on old research). There's other reasons at least as plausible, and we know they were adaptable people.

sss

[VillagePlank]

I know I said I wouldn't post here, but, to have a go at the question Jethro has asked, I thought I'd pop in and have a quick stab at answering.

Firstly, we need the data. Here's a chart:

This shows the Hadley temperature anomaly (1970-2000) along with the sea ice extent anomaly (1970-2000). This data has been standardised to fit between 0 and 1, so it's worth pointing out that the y-axis value is pretty much meaningless apart from quantitative magnitude. The data is normalised using the following formula:

V_n=(V_o-min(V_o))/(max(V_o)-min(V_o))

Here, V_n means value normalised, and V_o means value observed. The min function is the minimum value in the dataset, and the max function is the maximum value in the dataset. This little forumla, ensures that the values processed are always between zero and one, which is handy since a lot of the time climate data is presented in different units, and it can be difficult to assess magnitude. A point to note: this does not change the character of the dataset - ie when you chart it, it still looks the same. Take a look at the Hadley line in the above chart, for instance - instantly recognisable, even though I've squashed the values between zero and one. A side-effect is, of course, we can chart the two lines on the same graph - which is always handy.

From this, although I must be at pain to say that you don't need to squash the data in order to do this, we can measure how much the two lines correlate. I am using the Pearson test, and the value comes out at -0.76. So, we can say, that the two are reasonably inversely correlated. Don't worry about the 'inversely' bit, just deduct the sign (the minus bit) and you get the idea. This means, exactly, that 76% of the time that temperature goes up, sea-ice extent goes down.

I have not run the statistical significance of this, since I do not think the two are linearly seperable. Regardless of what others may think, sea-ice extent contributes to planetary albedo, and, therefore, it is likely that sea-ice extent and temperature are both a function of each other. To untangle this, here, is, I think, unsuitable.

Now, we have the odd problem of 24% of the time sea-ice extent has nothing to do with the temperature: ie other factors must come into play. This is, frankly, to be expected, since the climate is a complex beast, and numerous cyclical feebacks, and feedforwards interplay. One for debate, surely, but not for this exercise - since 24% may eat into the 76% as other factors change, and, of course, the converse is true.

So, what would sea-ice extent look like without CO₂ forcing?

Here's the IPCC forcing table - again adjusted to be between zero and one (take this one with a pinch of salt, however, since we only interested in the positive forcings here)

If we reduce the negative forcings to zero, which means we only include the positive forcings we can get a percentage of positive forcings that CO₂, according to the IPCC is responsible for:

Which gives us 51% of total positive forcings are attributable to CO₂. Now, taking a view from here, total natural CO2 emissions are about 552gt/yr whilst anthropogenic emissions are at about 29gt/yr which means about 5% of the CO2 included in the warming is from man. Whether or not that 5% is significant is another debate - but, I must add, the majority view is that it does.

So, anyway, 5% of man made CO2 against the 51% of CO2 forcing gives us 2.5%

So, on this back of a fag-packet analysis, I would say, Jethro, sea-ice extent would be 1.9% larger if man was not involved (76/100*2.5) EDIT: Sorry, 1.9% due to mans CO2 emissions - black soot, for instance, isn't included, but that wasn't the remit of the question.

I want to reiterate - this is a coffee break analysis, please treat this as such. The climate is much much more complex than this analysis allows for. For instance this percentage figure certainly needs to be increased to allow for reduced albedo.

EDIT: and I've got a stinking hangover.

Edited June 3, 2010 by VillagePlank

[Devonian]

...

G-W and Dev - for boats, they could go to 'Markland' (Labrador) for boat-building-sized trees, as well as having some supply from driftwood, and until near the end there were strong trade links with the rest of Europe (walrus ivory). In that way it's not like Easter Island at all. One bad winter doesn't wipe out a settlement - remember where these people came from (Iceland and Norway), and they have shown remarkable ability to adapt. Were one (or a few) bad winters enough to wipe them out they would certainly not have lasted 450 years. That's nearly as long as the time since Columbus! Longer/colder winters quite probably drove them to more heavily utilise the more secure food source of seals, but there's little reason to suggest it killed them (Diamond was speculating on old research). There's other reasons at least as plausible, and we know they were adaptable people.

sss

indeed and interesting. No doubt these were tough resourcesful people (but people who for some reason didn't eat much fish though the sea was teaming (?) with them).

So, was Diamond wrong to say the evidence is they recycled a lot of both wood (and especially iron)? I dount doubt they got wood from Newfoundland but it must have been risky and difficult to obtain.

So, $64,000 question, what did do for them? Combination of factors? Was Diamond way off the marks with his theory?

[Yorkshiresnows]

YS, NSSC and Dev, I've worked with the original researchers on this one (Greenland), and there is no evidence to demonstrate (a) significant environmental degradation (in fact there is evidence for the opposite), or ( elimination due purely to climate. That was an out-dated idea which Diamond included in his book. More recent research shows this not to be the case. For example, homefields in Greenland were manured (improved) so as to be more productive - they are still visible, and some are used today. The land did not become "inhospitable" in the LIA - less productive may be a better phrase, with the adaptation being to take more seals, but the diet was not exclusively marine even at the end. There is no historical evidence to show "no ice" like you suggest Y.S. (if there is, I'd love to see it, as would many of my colleagues!). The diet of the Norse had little fish (you're right Dev), and had progressively more and more seals into the early LIA. Many of the seals were the Harp seals, which follow the drift ice in early summer. Oddly enough, Harp seals made up 40% of the seal catch as recorded in middens in the earliest pahse from Brattahlid, and >30% of seal bones in all sites in all periods since 1000 AD, indicating that far from there being "no ice" there was indeed sea ice present. This is one of many lines of evidence to show that ice conditions in the MWP in Greenland were likely to be at least comparable to today, and my guess based on the Eastern Settlement data is probably with more ice.

Here's a sample reference on seals:

http://www.nabohome....Greenland05.pdf

Y.S., exactly what areas (settlements??) are covered by ice now that weren't in the MWP? If you can't provide some hard evidence I don't believe you.

You do also appreciate that the MWP is very pronounced in Greenland and NW Europe, but that Greenland/NW Europe is not the world (Jean Grove's "The Little Ice Age" is an excellent book BTW)? And what does a warm MWP in Greenland/NW Europe tell you about conditions in Asia, Africa, the Pacific, America? Not much...

Just like a cold winter in Europe, USA doesn't cover the fact that it was the warmest winter globally...

Jethro, why don't you ask the original authors if you're that concerned? [and in case you think otherwise, I'm not suggesting you have strong opinions on their conclusions BTW] I think it's an irrelevant point, as Arctic sea ice change is merely seen as a response to greenhouse forcing, and therefore certainly is not a fundamental pillar of the science. The retreat was predicted and is one of many predictions to come true, as shown by 30 years of detailed data and scattered older data. It is doing exactly as predicted. It may have retreated at some stage in the distant past, but so far as modern Arctic exploration and monitoring goes, the retreat is unprecedented. Graphs reconstructed back to early this century show only a little more ice than in the 1970s/80s, and so if you want my guess, then that should be your non-AGW baseline. But whether it is unprecedented or not, does not matter (not to me, anyway).

NSSC, your post is pure speculation, at odds with the physics of CO2 and our observations of the atmosphere (you do know the greenhouse effect has been observed?). As for water vapour, I'd like to know how you think there wouldn't be more water vapour in a warmer atmosphere!

http://www.skeptical...enhouse-gas.htm

sss

With regards to regionality of the MWP .... I know there are arguments for and against, but recent evidence would suggest a more global effect:

http://www.nature.com/nature/journal/v460/n7259/abs/nature08233.html

I DID NOT STATE THAT THERE WAS NO ICE AROUND GREENLAND but LESS ICE and the viking settlers were able to travel around Greenland, to the West coast of Nothern America and to Iceland.

Even if you dismiss the actual fact that the climate was a lot warmer through this period (baffles me, but its a free world), (The little ice age was written by Brian Fagan by the way .... perhaps there's another book of the same title by another author ?).

Here's a few snippets from this book of historical facts:

"Abundant cod and centuries of unusually mild conditions allowed the Greenlanders to voyage to North America and trade freely with Iceland and Norway in Walrus ivory, wool and even falcons. Their ships often carried exotic, valuable cargoes. In 1075, a merchant named Audin shipped a live polar bear from Greenland as a gift to Kinf Ulfsson of Denmark. Four centuries later, no one would have dared carry such a cargo eastward. If not for the medieval warm period, hundreds of years might have passed before anyone colonized Greenland and voyaged beyond its fjords".

Talking of when the Vikings first colonized the main land of Greenland (Eric the red and father Thorvald Asvaldsson were banished from Iceland and travelled west):

"They reached a western shore (Southwestern Greenland) and found summer pastures and thick willow scrub. Summers were brief but warm with longer days than Iceland, the winters harsh, but not especially so. They found better grazing than at home, abundant fish and sea mammals"

Further settlements colonized what became known as the Eastern settlements .... know known as the Julianehab and Narsaq districts. Another group pushed further North and founded the Western settlements centred around Sandnes Farm (Kilaarsarfik), in the modern-day Godthab district at the head of the sheltered Ameralik ford.

"Life in Greenland was easier than on the crowded hardscrabble fields of Iceland".

The west greenland current flows into baffin bay and the heart of Nororsetta, where it gives way to much colder south flowing currents. Cooler water passes southwards along Baffin Island, Labrador and eastern Newfoundland. This circulation pattern affects ice formation. The Baffin / Labrador coast has heavier ice cover and a longer sea ice season, whereas Greenland coast sea ice forms late and disperses early. There is often a coastal belt of ice-free water all the way up to the Arctic circle on the eastern side of the Davis Strait. The climate of the medieval warm period permitted easier navigation between Baffinland and Labrador during many summers.

"Between 800 and 1200 AD, warmer air and sea surface temepartures led to less pack ice than in earlier and later centuries. Ice conditions between Labrador and Iceland were unusually favourable for serious voyaging".

"In Iceland the Norse were able to obtain ample hay harvests for winter fodder and also to plant Barley, even near the north coast, where it was cultivated and until the 12th century. After that, farmers could never grow Barley in Iceland until the early 1900's".

Sort of suggests a warmer regime doesn't it ? There's an aweful lot more ..... but I think you should get the point.

MY POINT was to question GW's assertion that the arctic has never been in such a dire situation (in regards to ice cover) than at present times ........ but you should know this as my original post was in reply to that post.

I stated that we do not know for certain as we do not have accurate measurements of either land or sea temperature. What we do have is a lot of proxy data and historical records of farming and people movements throughout the Northern Europe, Iceland and Greenland .......... all of this data suggests a warmer stable climate that ran for the best part of 400 to 500 years 850 to 1250 AD.

My conclusion would be to suggest that there would likely have been less ice than now as a result.

Y.S

[Devonian]

...

Which gives us 51% of total positive forcings are attributable to CO₂. Now, taking a view from here, total natural CO2 emissions are about 552gt/yr whilst anthropogenic emissions are at about 29gt/yr which means about 5% of the CO2 included in the warming is from man. Whether or not that 5% is significant is another debate - but, I must add, the majority view is that it does.

...

Those forcing figures are for the change in atmosphere conc seen, why would you divide them in the way you do? Atmosphere conc has risen, due to our activities, by ~30% not 5%.

We're not going to have to go back to basics on the carbon cycle again are we?