General Climate Change

[Methuselah]

Yes but if that was the case, it still wouldn't be proof that AGW was responsible. Also the blog which this is taken from, is a well known extremists site.

Quite true, Solar...But, science will never prove anything to be 100% true or false; it disnae work that way. No one will ever prove that mankind's influence on matters atmospheric has been wholly benign, either...

[pottyprof]

So far, the reductions in both volume and extent are clearly unprecedented and have a direction (they are not apparently random variations, and not clearly tied to any other mechanism than AGW). Had, a mechanism such as the PDO been dominant, we should have seen at least one, probably two similar minima in thickness/extent in the last 100-150 years. We haven't. The decline of Arctic sea ice is one of the predictions of our theory of climate, but does not, by itself, confirm warming due to anthropogenic GHGs. When taken with the other evidence - direct observations of the enhanced greenhouse effect, specific spatial and temporal patterns of warming that confirm it's the GHGs doing it and not anything else, then the fact that we observe polar amplification as predicted means it's (in true IPCC-speak) very likely that the sea ice reduction is a consequence of AGW. In fact, it would be very remarkable if sea ice reduction was not occurring!

sss

At the end of the day it still just means there is less ice. As Jethro said, surely there must be some figures to make these assumptions? Or is it yet another area where A is happening so therefore B must be true?

[Gray-Wolf]

I think you'd be pretty secure if you are noting foram's and Diatoms that 'do' ice free ,warmer waters present across the Basin when the past 20 thousand years show only sporadic,localised, short lived introductions of such species that we are entering 'novel times'.

If we then look at what is different today to the rest of that expanse of time (pretty long cycle for those still clinging to natural?) we find man's influence on global temps, and the changes that is driving, as quite an obvious start point.

If it's not broke why fix it???? If we see our outputs/influence can drive such changes then is it not common sense to imagine that we DID drive them (in the absence of any compelling observations/evidence to the contrary?).

[Guest North Sea Snow Convection]

The available data in climate terms for ice movements is based over such an incredibly short period it is impossible to claim conclusive evidence for AGW as a cause. Very much a case of A happening so B must be true. The evidence in other areas claimed to buffer the AGW cause is so dependant on positive feedbacks being present to augment the warming effect that proponents of such beliefs continue to present supposition as being more than that. Supposition doesn't necessarily equate to 'very likely' either. It only does at present on a hopecast basis.

[Gray-Wolf]

Where would we like to start to examine the other 'wealth of evidence' that we have not faced such a basin wide phenomena in over an ice age (and probably 600,000yrs when Greenland's southern end was Forrest and grassland).

The 'industry wide standard' ,if I can put it this way, are the micro fossils, and the sea temp/ice cover/depth info that they lay down each year, but you seem reluctant to accept this as evidence of past polar conditions. May I add I find this troublesome as obviously a 'seasonal pack' would leave a blanket of evidence of that loss of ice and we do not see it. However we do see the very diatoms/Foram's now occupying ever increasing areas of the high Arctic and their remains are now raining down onto the deep sea muds to lay testament to the conditions 'up top'.

Coastal erosion. We see none of the markers of rapid coastal erosion of the permafrost from our recent past. The number of Inuit villages now being relocated to higher, more inland ,sites is unprecedented in their histories.

Macro fossils now falling out of the permafrost. Mammoths, mastedons and woolly rhino don't drop out all at once so past 'warm spells' would have allowed degradation (through bacteria) of the carcass to mark this 'warm phase' ,we see no degradation of past partial thaws in the carcasses we find/retrieve.

Loss of annual lakes. Lakes on the permafrost are draining due to permafrost melt (like the plug being pulled one scientist said) so herders are finding past areas of water /trout are now gone. There is no 'history' amongst the people of this happening in the past.

Methane spikes. The recent measure of methane spikes (Arctic now rivals the rest of the planets outputs) are a measure of permafrost melt, esp. the shallow shelf sea off Siberia, why do we not see similar 'spikes' in the recent Arctic history?

Berg droppings. With the melt off of ice sheets (Devon island) and shelfs (Ellesmere island) comes bergs and their cargo of rocks and stones (glacial erratics) which are deposited as the berg ablates. Where are such past deposits to be found to highlight past seasonal ice in the Arctic (the base of Nares is now littered with the remnants of Ellesmere islands ice shelf collapse).

Exposure to sunlight. Rock recently exposed to sunlight can be tested to find when they last saw the sun. We are finding an excess of 3,000yrs for the shelfs on Ellesmere and longer on the coast of Devon island and others within the archipelago.

In fact ,didn't I post similar only 6 weeks ago and got no evidence of past recent 'seasonal pack' in the high Arctic from anyone questioning why todays melt is 'novel'?

As I have said , nobody likes the disaster up north (well maybe fossil fuel does) but it is happening right now.....

If we are to be reassured it is a common event then show us the past 600.000yrs record of repeated basin wide retreats to a seasonal pack as I'm sure we'd all feel a lot better for it (well I certainly would!!!).

EDIT: And as Mark Serreze (NSIDC) puts it;

For the last 11,000 years or so we have been enjoying a relatively warm, low-ice interglacial period, with a gentle cooling as we head towards the next glacial. "From orbital variations, we'd expect the Arctic to continue to slowly cool as it has done so for the past several thousand years, eventually slipping into a new ice age," said Mark Serreze director of the US National Snow and Ice Data Center at the University of Colorado.

=======================================================================

So why choose now to become seasonal? would you not expect the opposite?

Edited June 1, 2010 by Gray-Wolf

[Admiral_Bobski]

Jethro is asking a very important question, and I am astonished that some on here seem unable to understand what she is asking.

If we know that the current arctic conditions are beyond the scale of natural variation then we must, by extension, know how far beyond natural variation these conditions are (since we must have a definition of "natural variation" by which to determine what lies outside of it).

So, what state would the arctic be in without AGW, and how do we know that?

The diatoms issue is irrelevant, since it only shows that we transitioned from an ice-free pole to a pole with Winter sea ice. Well, we still have winter sea ice even now, so it doesn't show that current levels are outside of natural variation. (Same goes for foraminifera, by the way.)

So we are left with Jethro's question, to which I still don't know the answer.

B)

If we are to be reassured it is a common event then show us the past 600.000yrs record of repeated basin wide retreats to a seasonal pack as I'm sure we'd all feel a lot better for it (well I certainly would!!!).

EDIT: And as Mark Serreze (NSIDC) puts it;

For the last 11,000 years or so we have been enjoying a relatively warm, low-ice interglacial period, with a gentle cooling as we head towards the next glacial. "From orbital variations, we'd expect the Arctic to continue to slowly cool as it has done so for the past several thousand years, eventually slipping into a new ice age," said Mark Serreze director of the US National Snow and Ice Data Center at the University of Colorado.

=======================================================================

So why choose now to become seasonal? would you not expect the opposite?

Show us the past 600,000 years record of non-stop all year round ice pack and maybe we'll talk.

I've posted (at least twice, now) explanations of why the "orbital variation" argument is spurious - in fact, not just spurious but plain wrong. Repeating the same comments again and again proves nothing (as several posters enjoy pointing out to some skeptics on here!).

[Gray-Wolf]

I've posted (at least twice, now) explanations of why the "orbital variation" argument is spurious - in fact, not just spurious but plain wrong. Repeating the same comments again and again proves nothing (as several posters enjoy pointing out to some skeptics on here!).

I thought I'd include Mark's summation for you C-Bob .

I'm sure you're sure of your info but I tend to favour Mark's known experience and expertise in the field above yours (no offence meant ,just pure 'favouritism').

I'm sure he'd be delighted to know the scale of the error he is committing by leading the likes of me into similar beliefs as his own and will readily make amends should you convince him he has erred

http://nsidc.org/res...os/serreze.html

I'm also sure he would not mind his reply to you re-publishing on here for us all to dissemble at our leisure .

In a matter such as this surely you cannot both be right/wrong???

Edited June 1, 2010 by Gray-Wolf

[jethro]

Jethro is asking a very important question, and I am astonished that some on here seem unable to understand what she is asking.

If we know that the current arctic conditions are beyond the scale of natural variation then we must, by extension, know how far beyond natural variation these conditions are (since we must have a definition of "natural variation" by which to determine what lies outside of it).

So, what state would the arctic be in without AGW, and how do we know that?

The diatoms issue is irrelevant, since it only shows that we transitioned from an ice-free pole to a pole with Winter sea ice. Well, we still have winter sea ice even now, so it doesn't show that current levels are outside of natural variation. (Same goes for foraminifera, by the way.)

So we are left with Jethro's question, to which I still don't know the answer.

:lol:

Thank you Rob, for a minute there I thought I was talking gibberish again, let's face it, not an unknown phenomena........

SSS and GW, my question refers back to the article posted on the previous page (but could apply to numerous other papers/articles) which states we now have less ice than the past however many years and it's definately due to AGW and outside the realms of natural variation.

In order to judge natural variation there must have been calculations made for various drivers of ice loss/gain whether that be orbital calculations, Solar input, PDO, AO, NAO and the miriad of other influences which together add up to a rough idea of what state we should expect the ice to be in. These HAVE to have been made. They won't be perfect, there will inevitably be a large margin of error but none the less, a rough figure will be known. Without such calculations and figures, the statement of "beyond natural variation" is impossible to make.

From these figures it is simple to calculate just how much above natural variation the ice loss is and therefore how much is attributable to AGW.

Simply saying the IPCC projection of expecting greater ice loss and Arctic amplification doesn't address the issue and could be seen as a bit of a cop out as that in it's self needs calculations to support the statement.

[sunny starry skies]

Hmmm, C-Bob, do I detect that you somehow don't believe that orbital forcing indicators would have us gradually heading towards the next ice age, without human intervention? That's a very bold statement and contrary to most of what we understand of past climate.

Jethro, I do understand that you are after understanding where the current Arctic sea ice fits within past variation, but it's a very similar argument to the question on where global temperature fits within past variations. The premise seems to go like this: "X change must be beyond the bounds of natural variation before we attribute it to AGW."

Yet it's a lame argument to make, as it gives no indication as to the cause of the variation, and ignore the valuable insight that palaeoclimate gives us, which is a measure of the sensitivity of the system. Global temperatures may have had some wiggles up/down with the MWP/LIA, and indeed were rather warmer ~6000 years ago. Does that mean we should take no notice of temperatures until they have surpassed the values of the mid-Holocene? Or the Eemian? Or the Pliocene?? No, of course not! The cause of temperature rise now is not the same as it was 1000 or 6000 years ago, and we know this because we can see the forcing happening, and we understand the cause now. We don't wait until the temperature change has passed some threshold, because we are not relying on some correlation, or identification of unusual temperature. We observe the greenhouse effect from the ground and from satellites, we observe the spatial pattern that tells us it's not the Sun (warm troposphere, cool stratosphere; day/night warming), we understand the radiative properties of the CO2 molecule and its effect on the absorbtion of IR radiation - this is enough to tell us that the cause is different and we should act now to slow our emissions.

Same goes for sea ice. You want to know if the dramatic reduction in area and volume we are observing this decade is unprecedented, but it does not matter, so long as we understand the cause of the change. Arctic ice is behaving exactly as expected under present atmospheric conditions, that is, that it is trending to ever smaller areas and volumes throughout the period of full-coverage observations) hence adding some weight to the AGW theory. Whether it did a similar thing under a different set of past atmospheric conditions (or, say, high-latitude insolation) is irrelevant, as different causes can lead to the same result. It does not change the fact that the Arctic warming, ice sheet melt and sea ice loss supports the fact that the Arctic is warming faster than the rest of the globe, in line with what we expect with increased GHGs.

If a palaeo record shows that the Arctic sea ice loss is unprecedented, or that seasonal ice has been observed before, what does that tell us? It tells us something about sensitivity of the Arctic sea ice, in the way that the MWP tells us about the sensitivity of global temperature change to forcing. We ought to hope that the present ice loss is unprecedented in the same way that we should hope that the many 'hockey sticks' of temperature are right.... it argues for a lower sensitivity, and less future warming/melting with the observed GHG forcing. But many "skeptics" would use high sea ice sensitivity/high past temperatures in completely the wrong way, not realising their folly!

sss

Edited June 1, 2010 by sunny starry skies

[Gray-Wolf]

Thank you Rob, for a minute there I thought I was talking gibberish again, let's face it, not an unknown phenomena........

SSS and GW, my question refers back to the article posted on the previous page (but could apply to numerous other papers/articles) which states we now have less ice than the past however many years and it's definitely due to AGW and outside the realms of natural variation.

In order to judge natural variation there must have been calculations made for various drivers of ice loss/gain whether that be orbital calculations, Solar input, PDO, AO, NAO and the miriad of other influences which together add up to a rough idea of what state we should expect the ice to be in. These HAVE to have been made. They won't be perfect, there will inevitably be a large margin of error but none the less, a rough figure will be known. Without such calculations and figures, the statement of "beyond natural variation" is impossible to make.

From these figures it is simple to calculate just how much above natural variation the ice loss is and therefore how much is attributable to AGW.

Simply saying the IPCC projection of expecting greater ice loss and Arctic amplification doesn't address the issue and could be seen as a bit of a cop out as that in it's self needs calculations to support the statement.

I think if you look at the link to the NSIDC heads page (above) you'll find he's been involved in many papers covering just such variability within the arctic climate system including a plethora of related areas of study which all point towards just how 'unique' the level of todays summer/perennial melt is ,and the changes this 'melt' has driven in the arctic.

If I have any concerns it is the 'lack' of understanding of the workings of the cryosphere we see when all of this information is freely available to us all?

I have tried, over the years, to pique an interest in the dramatic changes we are driving across the pole but it would appear that certain posters would rather instantly find a counter point than look further at any new evidence, and build an understanding in the area of study, from where to pick at the findings.

My postings over 'seasons end', this past 3yrs, has still left many on here choosing to believe in a 'recovery' , and to not credit the continued collapse of the perennial, come each October (yet when I show my 8yr old a Lego model of 'old perennial' ,then smash it up ,he grasps quite well how such majestic ice islands can produce quite a large splodge of 'ice extent' once collapsed???).

If they really have mistaken this 'collapse and spread' as 'recovery' then they really are in for a shock come September!!!.

With over a million years of a rich spread of data to study I DO believe we know that we are looking at something far beyond natural variability but how do you quantify that? Do we rely on Perennial ice levels (and it's ability to insure against summer melt out?) Do we look at 'open sea' areas as a percentage of Ocean come min extent? (as attested too by open water/warm water Foram's/Diatoms), do we look at the Halocline layer and it's construction/destruction?

The reality in the high Arctic that we would seem to be pointed towards (recently) is that we are now beyond a 'rebound' threshold having lost both perennial and Halocline (one cannot exist without the other, loose one and you loose them both!) so, though the years to come may bring variability in the amounts of ice we retain over summer, we will remain only one 'favourable to melt' season away from the 1 million sq km 'seasonal pack'.

The other 'reality' is that this situation is leaving a 'record' of itself that is easy to read and interpret and we are not finding such 'tell tale evidence' over the most recent 1 million years (or if we have someone needs to point me at it!!!).

One of the things that can lead to annoyance on my part is that if folk are aware of the evidence of past regional variability of the pack then they must also know of the unique situation we face today (every paper I've read on the subject has had this as a major point within the conclusion) but choose to ignore it! How can you deal with a person who will hide their 'understanding' for the sake of an argument?

S.S.S.

I believe C-Bob would have folk abandon any type of orbital forcing between the last ice age and the next possible point of dropping into such cooling in favour of some other 'greater' forcing that would effectively insulate us from our recent cyclical trends for the next couple of 'orbital forced coolings'.

I'm not convinced of this myself and the temp trend from the Arctic over the past 1100yrs seems to support this (well, apart from it bucking the trend and starting to warm over the last 100yrs)

As you see Mark (Serreze) has pointed out the generally held belief ( we are /should be cooling towards the next ice age) in his latest news article and I've suggested that he (C-Bob) approach Mark direct to discuss this difference.

Obviously, should Mark be wrong/out of date with his understandings, then (I imagine) many others will modify their beliefs along with him but I feel that for us to discuss this (once again!) would be unproductive and lead to folk withdrawing their posts for the foreseeable future (as some folk seem to do when they can argue no further?).

Edited June 1, 2010 by Gray-Wolf

[jethro]

You two are still missing the point and failing to answer the question.

SSS - I don't want to know if what we are seeing with the ice loss is down to AGW, I want to know how much ice loss is attributable to AGW.

I don't want to know if the loss is unprecedented, I want to know the calculations and figures behind that statement. I want to know and see the sums which show how that calculation was made, what it is based upon. I want to know how much ice we should have without AGW.

I don't doubt AGW, I don't doubt that we have the ability to contribute to climate change; I want to know the scale or magnitude.

Personally I don't see anything unproductive about discussing points time and again if it's exploring the subject and looking for answers. It only becomes unproductive when it's a debate of "yes it is, no it isn't" or "I'm right and you're wrong" then it's time to agree to disagree with that particular person, that doesn't however rule out the same discussion with someone else.

[pottyprof]

You have to love the way that people dodge questions.. You guys thought about taking up a seat in parliament? So are we to take it that there are no figures available and assumptions are the basis of good *coff* science?

[Gray-Wolf]

You have to love the way that people dodge questions.. You guys thought about taking up a seat in parliament? So are we to take it that there are no figures available and assumptions are the basis of good *coff* science?

What was the question again?

EDIT:.... oh yes , how much is man and how much nature. I'd say the bit that takes it beyond 'natural' is the bit that is man P.P.

The evidence seems to point to this loss of ice being a novel event over a very long time period (since the onset of the latest glacial era some would say) and that 'evidence' needs explaining somehow.

If we cannot find another novel driver that has been absent over this last glacial age then I (my own take) would say that man's tinkerings are behind it.

I'm not alone in thinking this as ,the last time I looked, the majority of climate science is saying the same.

So , what is your take on things P.P.? Man or something else?

Edited June 1, 2010 by Gray-Wolf

[jethro]

So there are no actual figures then to support these statements? No calculations, no possible way of supporting these assertions and certainly no way of discerning the level of our involvement.

Forgive me if I jam my cynic hat on a bit firmer.

[pottyprof]

:o

[Yorkshiresnows]

What was the question again?

EDIT:.... oh yes , how much is man and how much nature. I'd say the bit that takes it beyond 'natural' is the bit that is man P.P.

The evidence seems to point to this loss of ice being a novel event over a very long time period (since the onset of the latest glacial era some would say) and that 'evidence' needs explaining somehow.

If we cannot find another novel driver that has been absent over this last glacial age then I (my own take) would say that man's tinkerings are behind it.

I'm not alone in thinking this as ,the last time I looked, the majority of climate science is saying the same.

So , what is your take on things P.P.? Man or something else?

Hi GW

What exactly is that then ..... the evidence that is ... ?

I know there is a lot of proxy data that suggests there has been considerable ice-loss previously. We know of events such as the Roman warm period / medieval warm period and little ice age that certainly (without question) affected the Northern hemisphere in one way and then the other. Even closer to now in the 30's and early 40's there is at least some evidence to suggest rapid ice loss in the arctic region that switched round again to peak in the late 70's.

Are we to believe that a population of folk could colonise and farm an area in Greenland (grow cereal crops) that is now covered in ice and still believe that the arctic was itself unaffected less than now !!!!

We know that satellite data and accurate monitoring has only been in force since the late 70's (a time when the PDO switched so dramatically)...... so please could you provide the clear evidence that our current state (arctic ice loss) is so definately an unprecendented event ?

Cheers

Y.S

[Gray-Wolf]

So there are no actual figures then to support these statements? No calculations, no possible way of supporting these assertions and certainly no way of discerning the level of our involvement.

Forgive me if I jam my cynic hat on a bit firmer.

Explain these 'figures' for me Jethro (I think it is here that I struggle) and maybe I can see what science has to offer in the way of them.

Remember we are talking an area of the planet and it's workings (which is where I seem to be having my issues) so the 'results' are to be found as 'relics' of past environments (as far as I can gauge) like the wealth of environmental indicators as to conditions across that area of ocean/land/ice sheet etc.

Are you looking for this type of evidence as a statistic or am I on the wrong track there?

I think that for the 'sunlight' loving Foram's we accept 5% as the crossover point from partial ice to no ice so if the sample contains more than 5% of those particular species then we know that there was open water above. Am I getting warm or is this not 'evidence' (as far as past conditions of an area of Arctic Ocean is concerned?)

It would ,of course, be nice if we could both sing from the same sheet but I understand (from others) that we are all different (I'm not!) , we're all individuals, so if we choose to limit ourselves to our own areas then that is our own 'choice' but does make meaningful exchanges a tad awkward.

As things stand it would be nice if we could 'play to the gallery' and not seek to exclude the lurkers from our exchanges (whether intentional or not) by our use of language. I gather many of these folk take a great deal from reading the exchanges on this ,and other sites, and I feel we owe them a duty of care?

If your 'understanding' is correct then this is nothing more than another natter about our planet.

If my take is correct then we are witnessing an incredibly important moment in humanities history, equal to the eruption 74 thousand years ago, and we should allow as many to follow the conversation as we can both for the sake of that readership and also for our own future consciences.

[Yorkshiresnows]

YS, this is not a private conversation between you and SSS. Many others read your and others' posts, with interest and a desire to learn. Please, therefore, avoid such phrases as "I'll let you figure that one out for yourself" - if you think his statement is wrong, we would like to know why, and see your evidence. If you don't show us, we may tend not to believe you.

Oh, and while I genuinely appreciate your willingness to correct yourself, it would be preferable if you checked before, not after making such forceful and contradictory assertions - otherwise some of us may begin to doubt what you say before we start reading it, not after!

Hi,

Yes, I apologise ... you make a valid and fair point.

I think that due to the opposing (completely) view of Sunny Skies and Devonian to my own view .... then its best left for us to state that .... we agree to differ.

I would add however, that until very recently I was of the same opinion as the AGW folk ..... and perhaps it is best left for folk to look at the data themselves (there is so much now available free on line) and make up their own minds.

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.

I did make a mistake in my earlier post to Sunny Skies and should have properly checked before posting, and fair stick that I receive as a result. The argument that I have made however, is still a valid one (well at least to me ...!!).

Y.S

[MR EXTREMES]

we shall see gw we shall see.

solar minimum,

switch in pdo,

switch in jet stream behavour.

for years now the jet is struggling to get as far north as suggested it would in the mid 2000s when it became common media coverage that the jet could keep drifting futher and futher north this has done the oposite in recent years.

ofcoarse this is not the only driver of climate but add together the changes that have lead the global warming hype,

which i might add has futher pushed the powers that be to press for more and more action,trouble is some of which was used as evidence towards us burning our planet up is now wrong.

it seems that more and more saturation of this topic is pushing the public in the wrong direction,

after seeing poor summers and cold winters people just are not listening anymore and even so just because the arctic could melt away does not mean it will force a neg effect leading us into a cooler climate where the poles will freeze futher.

its happened before and it will happen again.

i will never listen to a bunch of fat cats trying to con the world out of money,

when i see the coldest winter since the 80s whether this is a one off or not we shall see.

graywolf you try to make it all sound so simple when its such early days.

Edited June 1, 2010 by badboy657

[Gray-Wolf]

graywolf you try to make it all sound so simple when its such early days.

I hope I do! (make things sound simple) for I think it is for all of us to have 'informed opinions' about the world we see changing around us.

As for 'early days' there are those who see signs that it is already 'too late' (and I'm not talking John and his cave visions here!).

As you wisely say (IMHO) 'time will tell'

[Admiral_Bobski]

I believe C-Bob would have folk abandon any type of orbital forcing between the last ice age and the next possible point of dropping into such cooling in favour of some other 'greater' forcing that would effectively insulate us from our recent cyclical trends for the next couple of 'orbital forced coolings'.

Well then, GW, you believe wrong. Here's a link to a post I made on 21st April about this very issue:

http://forum.netweat...ost__p__1807608

I am sure that orbital forcing has its part to play. I am dismayed by the oversimplification of the facts by the AGW brigade, "we're coming out of our Milankovitch optimum" being a prime example. The Milankovitch cycles are rather more complicated than just "here's an optimum and we're past it", and it can be shown to be an incorrect assertion anyhow.

I'm sure Professor Serreze's degree in Geography has been invaluable in his understanding of orbital forcings, and perhaps I shall e-mail him when I can find the time and enthusiasm (who knows - maybe I'll do it tomorrow). But here we are again with the "such-and-such says such a thing, therefore it must be (or is probably) true." I've put my position forward on this issue - interestingly, the last time I did nobody took the time or effort to argue the opposite case. Nobody pointed out how, where or why I was wrong and - surprise, surprise - we're now talking about the same issue as though we have learned nothing.

The old "ignore it and it'll go away" method.

EDIT - link to Mark Serreze's page at University of Colorado: http://cires.colorado.edu/people/serreze/

Hmmm, C-Bob, do I detect that you somehow don't believe that orbital forcing indicators would have us gradually heading towards the next ice age, without human intervention? That's a very bold statement and contrary to most of what we understand of past climate.

Just to clarify, I have no doubt that orbital forcing would, in time, have us gradually heading towards the next ice age. However, I would draw your attention to this section of the Wiki article on Milankovitch Cycles:

"An often-cited 1980 study by Imbrie and Imbrie determined that, 'Ignoring anthropogenic and other possible sources of variation acting at frequencies higher than one cycle per 19,000 years, this model predicts that the long-term cooling trend which began some 6,000 years ago will continue for the next 23,000 years.'More recent work by Berger and Loutre suggests that the current warm climate may last another 50,000 years.

The best chances for a decline in Northern hemisphere summer insolation that would be sufficient for triggering an ice age is at 130,000 years or possibly as far out at 620,000 years."

And here's some references:

J Imbrie, J Z Imbrie (1980). "Modeling the Climatic Response to Orbital Variations". Science 207 (1980/02/29): 943–953. doi:10.1126/science.207.4434.943. PMID 17830447.

Berger A, Loutre MF (2002). "Climate: An exceptionally long interglacial ahead?". Science 297 (5585): 1287–1288. doi:10.1126/science.1076120. PMID 12193773.

http://amper.ped.muni.cz/gw/articles/html.format/orb_forc.html

So is it as cut and dried as you and Gray-Wolf make it out to be? In short: No.

Edited June 1, 2010 by Captain_Bobski

[jethro]

Explain these 'figures' for me Jethro (I think it is here that I struggle) and maybe I can see what science has to offer in the way of them.

Remember we are talking an area of the planet and it's workings (which is where I seem to be having my issues) so the 'results' are to be found as 'relics' of past environments (as far as I can gauge) like the wealth of environmental indicators as to conditions across that area of ocean/land/ice sheet etc.

Are you looking for this type of evidence as a statistic or am I on the wrong track there?

I think that for the 'sunlight' loving Foram's we accept 5% as the crossover point from partial ice to no ice so if the sample contains more than 5% of those particular species then we know that there was open water above. Am I getting warm or is this not 'evidence' (as far as past conditions of an area of Arctic Ocean is concerned?)

It would ,of course, be nice if we could both sing from the same sheet but I understand (from others) that we are all different (I'm not!) , we're all individuals, so if we choose to limit ourselves to our own areas then that is our own 'choice' but does make meaningful exchanges a tad awkward.

As things stand it would be nice if we could 'play to the gallery' and not seek to exclude the lurkers from our exchanges (whether intentional or not) by our use of language. I gather many of these folk take a great deal from reading the exchanges on this ,and other sites, and I feel we owe them a duty of care?

If your 'understanding' is correct then this is nothing more than another natter about our planet.

If my take is correct then we are witnessing an incredibly important moment in humanities history, equal to the eruption 74 thousand years ago, and we should allow as many to follow the conversation as we can both for the sake of that readership and also for our own future consciences.

OK, I'll try again.

My questions stem from that article you posted last week (to be fair, it could have been any one of the number of papers which have claimed the same), it piqued my curiosity and got me wondering.

He's the crucial bit......

But the last 100 years have bucked the trend in a big way. "We've lost about 30% of the summer ice extent and as much as 85% of the multi-year ice volume since the 1970s," Serreze told environmentalresearchweb. And this decrease can't be explained by natural variations alone. "If you ignored our recent atmospheric carbon dioxide rise, the recent reduction in sea ice in the Arctic would look highly anomalous, because it comes at a time when orbits favour extensive sea ice," said Richard Alley from Pennsylvania State University.

Publishing their findings in Quaternary Science Reviews, Polyak and his colleagues conclude that the recent decrease in Arctic sea ice doesn't fit any of the natural variabilities known from existing paleoclimatic data. This conclusion implies that the most plausible trigger for this warming is rising atmospheric carbon dioxide levels coming from human activities. "Orbital variations, which are currently slowly cooling the Arctic, are still there, it's just that climate warming due to human activities is now dominating and operating on a much shorter timescale – about 100 years – than orbital variations – [which operate over] thousands of years," explained Serreze.

These two paragraphs state that natural variation cannot explain the ice loss. Fair enough, not questioning that, if that's their conclusion, I accept it. But......(and this is where you seem not to follow) they MUST have calculated what normal levels of ice should be. They say Orbital variations are currently slowly cooling the Arctic, they make references to paleo records (presumably to compare previous Orbital cycles) so they must have an idea of the amount of ice which should be there.

They also say the decrease since the 1970's cannot be explained by natural variation - again, fair enough, not questioning their conclusion. But......Orbital changes since the '70's are so small to be insignificant as a measurement. Therefore, they must have measured other more immediate drivers of change such as the various ocean cycles and Solar output.

If they (as they must have done, to reach this conclusion) measured both historical and recent years components which contribute to ice levels, both positively and negatively, they must have figures for what they would expect the levels to be. From that point they could then deduct what the actual figures are and have a figure for the difference which would be a rough estimate of our contribution to the loss. That's the figure I would like to know - how it's expressed, percentage, statistic or ice volume is of no matter, I just want a figure or even a rough estimate.

Just in case I have excluded any lurkers or other members (apologies, didn't intend to) PLEASE join in. I really don't mind who answers this question, I just want an answer.

GW.....this bit

"and we should allow as many to follow the conversation as we can both for the sake of that readership and also for our own future consciences."

Sorry, you lost me with that bit

[pottyprof]

You don't think anyone would take a wobble seriously do you? I mean finances as they are, surely they won't look at things wobbling?

Oh... hang on a mo... oh yeah..........

[Gray-Wolf]

http://news.mongabay.com/2010/0601-hance_snowcover.html

Just a little balancing act to offset the tales of imminent ice age we were hearing in Feb!

If AGW is to bring more extreme snowfall events it seems it'll mop them up later on!!! (just a joke)

I know of some studies in the rockies that show early snow melt means not only swollen rivers but also higher summer temps as the snowfields no longer chill the air (and of course the albedo of rock is a lot lower than snow so more heat is absorbed to be re-radiated.

[Methuselah]

The available data in climate terms for ice movements is based over such an incredibly short period it is impossible to claim conclusive evidence for AGW as a cause. Very much a case of A happening so B must be true. The evidence in other areas claimed to buffer the AGW cause is so dependant on positive feedbacks being present to augment the warming effect that proponents of such beliefs continue to present supposition as being more than that. Supposition doesn't necessarily equate to 'very likely' either. It only does at present on a hopecast basis.

Isn't that supposition??