[Pete Ridley (OP)]

Hi Wiybit, your

So you are therefore saying that you know why Co2 moves as it does, and know of a better way to model it?

is way off beam. I have never said that so please don’t distort what I say. You can check my previous comments and the links to other comments of mine elsewhere to refresh your memory on what I am saying.

Regarding

Except enviroment is a huge area of science ..

I am only really interested in talking about climate change and on this thread only in getting an answer to my question about kinetic v collision diameter from someone having the required level of expertise. I thought that I had made this clear in my very first comment here 5 days ago. Here again is what I said

.. I have a question that has been puzzling me for over a year now and remains unanswered despite asking it of experts in the subject. My question in a nut shell to the scientists here is “why do paleo-climatologists use collision diameter in preference to kinetic diameter when considering the migration of air molecules through firn and ice”?

I can’t see anything ambiguous about that excepting perhaps for someone who doesn't know what firn is or why paleo-climatologists are interested in the movement of air molecules in ice. I don’t recall having commented here on any other aspect of the environment.

Hopefully BenV will soon be able to find someone who has the necessary expertise and inclination to give me a satisfactory answer

Best regards, Pete Ridley

[Jolly- Joliver]

Hi Wiybit, your

So you are therefore saying that you know why Co2 moves as it does, and know of a better way to model it?

is way off beam. I have never said that so please don’t distort what I say. You can check my previous comments and the links to other comments of mine elsewhere to refresh your memory on what I am saying.

That's fine I never intended to distort what you said, I asked a question, knowing that we had discussed that before(generally you say NS people can answer you) you stated that under your hypothesis, that the way they currently model is inncorrect, and the way you believe they should model, would work better.

There is the problem you suggest an understanding of the models and propose what you consider to be a better way, yet you are talking in open Hypothicals. That lead me ask what I did because you failed to clarify your understanding.

I am kinda left to conclude that you have a basic understanding of how they do the maths, you see there are things they ignore and are certain they are wrong, yet at times express yourself with a certainity that you really do not have.

Does that make sense? I am not saying that to have a go at you, I have been trying to help you find an answer to your question and still am, but to express certainity when you are not, is slightly contradictory.

Regarding

Except enviroment is a huge area of science ..

I am only really interested in talking about climate change and on this thread

Maybe but that does not chage the reality that enviromental issues and topics are far farer reaching than just climate change, just because there is a enviromental section does not mean you should expect every type of enviromental scientist to be present.

[Pete Ridley (OP)]

Hi Wiybit, In my second comment here, on 13/04/2011 @ 21:58:19, I said specifically for your benefit [quote .. The researchers that I mentioned in my first comment ignore kinetic diameter and use collision diameter, which I hypothesise is not appropriate when the diameter of pores within and the channels that link ice air pockets approach the size of those smaller molecules as the ice is reaching the final stages of compression to a state where the air pockets become “closed off”[/quote] Note that phrase “ .. which I hypothesise .. ”.
My definition of hypothesise is pretty close to the following

Verb   1.   hypothesise  - to believe especially on uncertain or tentative grounds;

(http://www.thefreedictionary.com/hypothesise).

If you use a different definition then that could account for why you incorrectly say

.. So you are therefore saying that you know why Co2 moves as it does, and know of a better way to model it?

Hypothesising (i.e. speculating) is a long way off knowing therefore your statement was, as I said before

.. way off beam ..

I don’t believe that my hypothesis says that

.. the way they currently model is inncorrect, and the way .. they should model, would work better

It only says that I speculate that they should use a different measure of molecular diameter in their models.

You say

.. There is the problem you suggest an understanding of the models and propose what you consider to be a better way ..

but I don’t think that I have ever claimed to know any details of how their models work. All that I know is that they say they use collision diameter in their modelling and I speculate that they should be using kinetic diameter (and asked Severinghaus if he had run his model using that measure).

It is because I speculate about this that I have repeatedly asked the “experts” to explain why they choose to use collision diameter. In my opinion that is simply proposing the use of a different parameter, not proposing a better way of modelling the process. I’m not qualified to do the latter, but am entitled to speculate about using an alternative measure that I understand is used by gas purification practitioners in their operational systems when considering similar processes. The use of this alternative measure could well overturn the conclusions that the ice core “experts” draw from the results of their modelling about their ability to reconstruct past atmospheric concentration of CO2.

I think that I have provided you with an excellent reference book (“Materials science of membranes for gas and vapor separation”) from which, if you are inclined, you can develop a better understanding of the circumstances under which the different measures of molecular diameter are applied.

I don’t understand how you can conclude that I

.. have a basic understanding of how they do the maths, .. see there are things they ignore and are certain they are wrong ..

. I have questioned only one thing, why do they prefer collision over kinetic diameter. If I was “certain they are wrong” I would say loud and clear “you are using the wrong measure of molecular size”. Have I done that? If you think so then please tell me where I said it and I’ll withdraw the comment.

As for your

.. enviromental issues and topics are far farer reaching than just climate change, just because there is a enviromental section does not mean you should expect every type of enviromental scientist to be present ..

have you looked at the categories that The Naked Scientists list under the Life Sciences forum heading “The Environment”? They are

.. Meteorology, ecology, climate change and conservation

(http://www.thenakedscientists.com/forum/).

Best regards, Pete Ridley

[yor_on]

Wow, this thread should really attract interest

It has all the ingredients. A lot of 'learned words' and it's argumentative in the best/worst American definition of a so called high school 'debate'. Furthermore it sounds as if it knows what it discuss also effectively telling those that don't agree that they are ignorants

I do not expect Ben to be such a person Peter. I expect him to know his limits exquisitely well, and what's even better, acknowledging them too which is more than I can say about some. The road to wisdom is to know when you're out of your depth, which won't stop us from making educated guesses though You come to the site, telling moderators that they 'don't know what they are talking about', thereby implicating that you do (by inference there). A classical debate trick, often used in those society's thriving on 'free debate', throwing verbal manure at each other.

Why not try to see if you can shorten your question instead? To something more simple and understandable. That's what Einstein did, and if he could so can you, right?

But as I read you it's a question of if we can prove that the ice samples containing air bubbles can be guaranteed to have the exact same atmosphere (and CO2 concentration?) As there was in the atmosphere when the ice layers came to be historically? I might be wrong as I lost myself in your formulations repeatedly, but if that was what you meant, I think the question is valid, and good.

"Such air is found in bubbles trapped in annual layers of ice in Antarctica, in sealed brass buttons on old uniforms, airtight bottles of wine of known vintage, etc. Additional support comes from well-dated carbon-isotope signatures, for example, in annual tree rings. Estimates of "pre-industrial" CO2 can also be obtained by first calculating the ratio of the recent atmospheric CO2 increases to recent fossil-fuel use, and using past records of fossil-fuel use to extrapolate past atmospheric CO2 concentrations on an annual basis.

Estimates of "pre-industrial" CO2 concentrations obtained in this way are higher than those obtained by more direct measurements; this is believed to be because the effects of widespread land clearing are not accounted for. Ice-core data provide records of earlier concentrations. For concentrations back to about 1775, see A. Neftel et al.

The record derived from the DSS Antarctic ice core indicates an average concentration of 280.05 ppm from 1000-1750 C.E. For over 400,000 years of ice-core record from Vostok, see J. M. Barnola et al.. For ice-core records extending over 650,000 years back in time, see Siegenthaler et al. (2005)." From Recent Greenhouse Gas Concentrations
==

"The latest results from the EPICA core in Antarctica have just been published this week in Science (Siegenthaler et al. and Spahni et al.). This ice core extended the record of Antarctic climate back to maybe 800,000 years, and the first 650,000 years of ice have now been analysed for greenhouse gas concentrations saved in tiny bubbles. The records for CO2, CH4 and N2O both confirm the Vostok records that have been available for a few years now, and extend them over another 4 glacial-interglacial cycles. This is a landmark result and a strong testament to the almost heroic efforts in the field to bring back these samples from over 3km deep in the Antarctica ice. So what do these new data tell us, and where might they lead?

Composite CO2: Click to enlargeFirst of all, the results demonstrate clearly that the relationship between climate and CO2 that had been deduced from the Vostok core appears remarkably robust. This is despite a significant change in the patterns of glacial-interglacial changes prior to 400,000 years ago. The ‘EPICA challenge’ was laid down a few months ago for people working on carbon cycle models to predict whether this would be the case, and mostly the predictions were right on the mark. (Who says climate predictions can’t be verified?).

It should also go almost without saying that lingering doubts about the reproducibility of the ice core gas records should now be completely dispelled.

That a number of different labs, looking at ice from different locations, extracted with different methods all give very similar answers, is a powerful indication that what they are measuring is real. Where there are problems (for instance in N2O in very dusty ice), those problems are clearly found and that data discarded.

Secondly, these results will allow paleoclimatologists to really look in detail at the differences between the different interglacials in the past. The previous 3 before our current era look quite similar to each other and were quite short (around 10,000 years). The one 400,000 years ago (Marine Isotope Stage 11, for those who count that way) was hypotheisied to look more like the Holocene and appears to be significantly longer (around 30,000 years).

Many of the details though weren’t completely clear in the Vostok data, but should now be much better resolved. This may help address some of the ideas put forward by Ruddiman (2003, 2005), and also help assess how long our current warm period is likely to last.

More generally, since the extra interglacials that are now resolved have very different characteristics from the previous ones, they may allow us to test climate theories and models over a whole new suite of test cases. To quote Richard Alley “Whether you’re a physicist, a chemist, a biologist, a geologist, or any other “ist” studying the Earth system, there is something in these data that confirms much of your understanding of the planet and then challenges some piece of your understanding”. It’s all very exciting (for us ‘ists’ at least!)." From 2005. RealClimate.

And this one might give some insight too. Reliability of ice-core science: historical insights. As well as this. Atmospheric nitrous oxide during the last 140000 years (.pdf) That takes up the nitrous oxide question mentioned in RealClimate.

( But the only way to really prove that this isn't another of those mad potconjunctures cooked up by those conspiratorial climatologists, physicists and geologists (et al:) is naturally to do as Methuselah. If we just could find someone like him. Even though he is said to only have lived a measly 1000 y it would still be of interest I think? Providing that he regularly corked those air samples, or Jonah maybe, naah, not him? The flying Dutchman then? And hey, i got it. That roman soldier that was there at the crucifixion, doomed to live forever, then we could, at last, get some good ol'human, down to earth, correlations to test it against

As it is we have to make do with what we have, and correlate it to other sources and see if the concentrations agree, and when not, try to find the reasons for the discrepancy.
==

Lastly.

"The most direct method of investigating past variations of the atmospheric CO2 concentration before 1958, when continuous direct atmospheric CO2 measurements started, is the analysis of air extracted from suitable ice cores. Here we present a new detailed CO2 record from the Dronning Maud Land (DML) ice core, drilled in the framework of the European Project for Ice Coring in Antarctica (EPICA) and some new measurements on a previously drilled ice core from the South Pole. The DML CO2 record shows an increase from about 278 to 282 parts per million by volume (ppmv) between ad 1000 and ad 1200 and a fairly continuous decrease to a mean value of about 277 ppmv around ad 1700. While the new South Pole measurements agree well with DML at the minimum at ad 1700 they are on average about 2 ppmv lower during the period ad 1000–1500. Published measurements from the coastal high-accumulation site Law Dome are considered as very reliable because of the reproducibility of the measurements, high temporal resolution and an accurate time scale.

Other Antarctic ice cores could not, or only partly, reproduce the pre-industrial measurements from Law Dome. A comparison of the trends of DML and Law Dome shows a general agreement. However we should be able to rule out co-variations caused by the same artefact. Two possible effects are discussed, first production of CO2 by chemical reactions and second diffusion of dissolved air through the ice matrix into the bubbles. While the first effect cannot be totally excluded, comparison of the Law Dome and DML record shows that dissolved air diffusing to bubbles cannot be responsible for the pre-industrial variation. Therefore, the new record is not a proof of the Law Dome results but the first very strong support from an ice core of the Antarctic plateau."

By SIEGENTHALER, U., MONNIN, E., KAWAMURA, K., SPAHNI, R., SCHWANDER, J., STAUFFER, B., STOCKER, T. F., BARNOLA, J.-M. and FISCHER, H. (2005), from 1. Climate and Environmental Physics, Physics Institute, University of Bern, Bern, Switzerland 2. CNRS Laboratoire de Glaciologie et de Géophysique de l'Environnement (LGGE), Grenoble, France 3. Alfred Wegener Institut für Polar- und Meeresforschung, Bremerhaven, Germany.

But as that one is 'pay for view' from Wiley Online Library / Wiley InterScience I can't link that pdf, which is a shame. Anyway, you got some references I hope. If that now was your question?
==

As for kinetic diameter, versus collision diameter? Well, exactly how should we construct that experiment? over what time period? We have the ice cores from 'human reckoning' to compare to trees, rocks, sediment etc of course. And they do seem to fit/correlate to each other? Although that only should be over a measly ?? Thousand years maybe, or so Could that make do for a comparison/verification?

[Pete Ridley (OP)]

Hi yor_on, I had wondered if it would be long before you turned up here. I have seen comments of yours relating to questions about both “climate change” and “Physics, Astronomy & Cosmology” topics and the impression that I get is that you have a good understanding of the latter. I expect that you would even be able to make a worthwhile contribution to the work that Professor Andrew White is doing at CERN (my comment on 17th @ 11:36:14).

It seems to me that you express opinions on the former from a position of ignorance comparable to mine, so may have more to learn from the exchanges here than to contribute. Of course I may be wrong so, even though you use a false name, are you prepared to disclose the extent of your scientific expertise in the subject of molecular dynamics beyond that you may be a good runner (http://www.thenakedscientists.com/forum/index.php?action=profile;u=9199)?

Your 1612-word comment quotes from and links to some very interesting stuff about those attempts to reconstruct past atmospheric CO2 content using air “trapped” in ice for decades, centuries and millennia (although I am always suspicious of anything that appears in that “Hockey Team” blog Realclimate) but it does nothing that answers my simple question.

You ask

Why not try to see if you can shorten your question instead?

but how much shorter than

.. why do paleo-climatologists use collision diameter in preference to kinetic diameter when considering the migration of air molecules through firn and ice ..

do you need? I stated that simple question in my opening comment on The Naked Scientists blog and have repeated it twice on this very page, only yesterday at 10:04:48 then again at 18:59:37. Have you bothered to read this thread before commenting or have you simply jumped in blind? How you can paraphrase that simple question as

it's a question of if we can prove that the ice samples containing air bubbles can be guaranteed to have the exact same atmosphere (and CO2 concentration?) As there was in the atmosphere when the ice layers came to be historically?

is beyond me.

So, your

Anyway, you got some references I hope. If that now was your question?

is way off beam because you have simply provided quotations and links that contributed to answering your own mistaken interpretation of my question.

Your

As for kinetic diameter, versus collision diameter? Well, exactly how should we construct that experiment? over what time period?

again has nothing to do with my simple question. As far as I am aware I have not asked for any experiment about kinetic v collision diameter so please would you point to where you think that I have done so. What I have done is ask Professor Jeff Severinghaus, one of the “experts”, if they have run their model substituting kinetic for collision diameter.

I have already had discussions with Professors Richard Alley, Severinghaus and Bender about the other proxies such as

.. trees, rocks, sediment etc of course ..

and my scepticism about the statistical manipulations used to make them

..  fit/correlate to each other

You may find the article “Uncertainty in Climate Change (WP)” by A.T. Grove and E. Lopez-Gunn (http://www.realinstitutoelcano.org/wps/portal/rielcano_eng/Content?WCM_GLOBAL_CONTEXT=/elcano/elcano_in/zonas_in/dt25-2010) of interest but that really is another question which I suggest that you raise separately if you wish to learn something about those other proxies.

Best regards, Pete Ridley

[yor_on]

Peter I'm always in a state of confusion

It's only when I've finally translated what others say and tell me into my own that I understand what they mean. That's also why I wondered what you meant, you see on TNS we have all kind of expertise, but only a very few of them, if any, believe themselves to be modern Leonardo Da Vinci's. Insulting remarks usually lead to a ban here. We're not really interested in mudslinging,  we are interested in learning and sharing what we know though. It can become a difficult balance act to know where one end (learning) and the other takes over (mudslinging) but we try

As for your reference I will look at it, but to build the contention on your idea of the difference, without presenting anyone agreeing is a hard thing to do. Doesn't necessarily mean that your ideas is wrong but you should really try to find some supporting evidence before contending what everyone 'mainstream' think is true. And that's why I asked you for ideas of how you would like to see a experiment made.

You seem quite skilled in innuendo and debate technique though
==

As for the 'think tank' you linked me too? Driven by business, for business maybe, with the trustees and corporations being made board members, maybe? See, I can do innuendo too

It's been in my sorry experience that when I read about some new, or not so new, 'institution' contending climate science, I always will benefit from looking at its 'founders'. All to often you can find that, although all of those organizations proudly declaring themselves 'independent', that they in deed are influenced by the ideas of their 'financial support'. Which in a way is nothing remarkable, just a human fact. It's very hard to make anything 'independently' outside the academic sphere, if even there(?) nowadays. Not even 'independent investigating journalism' is really independent today, as can be seen in any modern war, and how those journalist finds the opportunity to report 'independent views'?

But yes, I will read it. I always do.

[yor_on]

Well I looked it over. Actually a quite nice article, summarizing what we think us know, staying somewhat on the conservative side, carefully avoiding to discuss man made contributions more than in passing. It's a good one I think, I will have to reread it later. As for now I'm still not fully awake. Take me a lot of coffee to get me working those days

And I'm not really making fun of you, even though I found the discussion quite inflamed. I'm interested in how you think you could prove your point, and to me that would need 'experimenting'. Assume that we had climatologists here that research, I doubt that they would get involved in this myself. But if you could present a way to simply test it, and that should mean a long term test of it also as I see it, realistically. Maybe some of them would get ideas from a proposition?

So, if it was you wanting to test it, how would you do it?

Myself I would prefer a 'secluded area', meaning not easily contaminated by human activity, where you could measure the atmospheric conditions continually and then compare the layers of snow/ice to those results you get. That wouldn't exactly answer your 'physics' question, but it would tell us if there was a correlation between the atmosphere and the bubbles formed, and also the isotopes, with what we then would measure continuously.

And that would be the important thing to me. And as I'm guessing this is what your question really discuss too? That is, if we are responsible for the climate changes we observe today, and casting into doubt the foundations on where our climatology builds historically. In this case the ice cores we use for comparison. The real problem with your question is that this is already done, continuously as I see it. And if that ice trapped air would give us the wrong results we should have noticed it by now?

Well, as I see it.

[yor_on]

Here you have a description of some techniques used for differing the time-lines involved and how the measuring is done.

Ice-core evidence of abrupt climate changes. 

And here is some other indirect evidence for it working.

"We reconstructed the radiocarbon activity of intermediate waters in the eastern North Pacific over the past 38,000 years. Radiocarbon activity paralleled that of the atmosphere, except during deglaciation, when intermediate-water values fell by more than 300 per mil. Such a large decrease requires a deglacial injection of very old waters from a deep-ocean carbon reservoir that was previously well isolated from the atmosphere. The timing of intermediate-water radiocarbon depletion closely matches that of atmospheric carbon dioxide rise and effectively traces the redistribution of carbon from the deep ocean to the atmosphere during deglaciation."  From Marine Radiocarbon Evidence for the Mechanism of Deglacial Atmospheric CO2 Rise. (pay site)

And here you have a geological study studying Firn and 'gas transportation' " This study aims to establish the continuity of the gas record at Mt. Moulton, correlate the MBI#1 record to the Vostok EGT4 timescale through the development of MBI#1 age models, interpret the length of the Eemian period in the MBI#1 record and investigate the link between northern hemisphere insolation and Antarctic temperature as expressed in the MBI#1 isotopic temperature record." It also discuss "gas transport within firn" separating it roughly into convection, diffusion and 'non-diffusion', quite interesting in fact. Thesis.

As for the pure physics of it?
'Geology, Palaeontology & Archaeology' ?
Maybe ask in Chemistry?
Or General Science.

It a field where everything goes into everything else it seems.



 

[Jolly- Joliver]

I don’t understand how you can conclude that I

.. have a basic understanding of how they do the maths, .. see there are things they ignore and are certain they are wrong ..

. I have questioned only one thing, why do they prefer collision over kinetic diameter. If I was “certain they are wrong” I would say loud and clear “you are using the wrong measure of molecular size”. Have I done that? If you think so then please tell me where I said it and I’ll withdraw the comment.

No need to withdraw comments, and I am not going to go back through all the past conversations, but I am sure you expressed a certainy before about the methods they used being wrong. My point relating to hypothesis was simply that they can be at varying degrees also, from a hypothesis you are more sure of as a possible explaination to ones more you are less sure of as a possible explaination, by saying "open hypothesis" I meant in the middle.

 

As for your

.. enviromental issues and topics are far farer reaching than just climate change, just because there is a enviromental section does not mean you should expect every type of enviromental scientist to be present ..

have you looked at the categories that The Naked Scientists list under the Life Sciences forum heading “The Environment”? They are

.. Meteorology, ecology, climate change and conservation

That still doesn't really change my point.

Besides I was only trying to help you get an answer and I hope that I have, there is no need for us to go on and on about this as you say 'but it says Climate change' and I say but climate change has different areas also...

Peace

[Jolly- Joliver]

Assume that we had climatologists here that research, I doubt that they would get involved in this myself. But if you could present a way to simply test it, and that should mean a long term test of it also as I see it, realistically. Maybe some of them would get ideas from a proposition?

So, if it was you wanting to test it, how would you do it?

Rather than going off to the north or south polls could you not use a snow machine? The flakes might be formed slightly differently than in nature but using extraplation it could be a simply way to test it, no? 

All snow flakes are different anyway...

[Pete Ridley (OP)]

Hi yor_on, I’m delighted that you found that article “Uncertainty in Climate Change” of interest but I’m sure that you can find a source of such information that you feel more comfortable with. There are good reasons to be suspicious of arguments presented by organisations on both sides of the climate change debate as each individual involved has his or her own agenda. It’s all of that uncertainty that leaves most of us in a state of confusion and leaves me so sceptical of anything that I am told, particularly when politicians are involved and especially after “The Hockey Stick Illusion” and Climategate. You

benefit from looking at its 'founders'

and I “Follow the money”.

I’m afraid that your

.. but to build the contention on your idea of the difference, without presenting anyone agreeing is a hard thing to do

conveyed nothing to me.

I don’t understand why you keep talking about an experiment in relation to my question here. I’ve already covered that point so won’t dwell on it but I will pick up on your

Doesn't necessarily mean that your ideas is wrong but you should really try to find some supporting evidence before contending what everyone 'mainstream' think is true

If you have read my previous comments carefully enough you should have learned that my “ideas” that:
a) preferential molecule size dependent fractionation of atmospheric gases occurs in an ice sheet,
b) collision diameter rather than kinetic diameter is used during analysis of air from ice,
c) kinetic diameter is relevant when considering gas molecules moving through nanoporous substances,
are supported by evidence. That evidence has been provided by some of those

everyone 'mainstream'

scientists themselves.

Let me repeat the reference that I gave here on 17th @ 17:49:08 and again on 18th @ 10:04:48. “Evidence for molecular size dependent gas fractionation in firn air derived from noble gases, oxygen, and nitrogen measurements” by C. Huber, U. Beyerle, M. Leuenberger, J. Schwander, R. Kipfer, R. Spahni, J.P. Severinghaus and  K. Weiler.

It is clear even just from the title that this paper provides evidence of a). The evidence for b) is provided in that same paper by doing a simple search for “diameter”, the second occurrence of which is in Table 2, which shows

Collision diameter (Å)

for 8 atmospheric gases. There is no mention of kinetic diameter. Finally, evidence for c) abounds and can be found by simply Googling - “porous” “kinetic diameter” - or – “nanoporous” “kinetic diameter”.

I didn’t expect to have to spell all of that out to The Naked Scientists, considering the university that they attended.

When you say

we are interested in learning and sharing what we know

I assume that by “we” you mean The Naked Scientists. I share that interest, but for me it is mainly learning because I don’t have all that much to share as far as the numerous scientific disciplines involved in improving our poor understanding of the processes and drivers of the different global climates is concerned. It’s a pity that we all let ourselves get sucked into slinging the mud.

Thanks for trying to help but none of the papers that you referred to helps to answer my specific question here. I wasn’t able to locate “Geology, Palaeontology & Archaeology” which I assume is a book. If you know that it says something about the kinetic diameter of gas molecules or the movement of gas molecules in nanoporous substances then it would be of interest and I’d appreciate more information about it.

BTW, are you one of The Naked Scientists or just a blogger like I am?

Best regards, Pete Ridley

[yor_on]

Well, I would suggest you put your question where it belongs. I gave you what I suspect might be appropriate 'forums' here in my former post. I'm not sure it is placed in the right forum if it's just a geology/chemistry or physics question. To place it in 'The Environment' and call it "Another Hockey Stick Illusion" just makes me think I'm answering your questions as good as is possible?

Still, if you find them wrong for your question you probably should try those other threads instead, and ask there, and good luck with that. This sub forum is about the environment.
==

You are quite close to sounding querulous here?

If you find the quality of answers offensive to your sensibilities you really should look for another place. Just find a site of 'better quality' and start a thread there instead. As it is I'm starting to wonder what your real agenda is?

[BenV]

Yor_on is a valued member of this forum, but not a member of Naked Scientists staff.  Please stop whining about us, I have told you I will put your question to a relevant researcher when the opportunity presents itself.

[Pete Ridley (OP)]

Hi yor_on, I am astounded by your

I'm not sure it is placed in the right forum if it's just a geology/chemistry or physics question

I’m not the only one who considers that questions about fundamental theories underpinning opinions on the causes of climate change belong here on the Life Sciences, The Environment, forum. Let me give you some random examples but there are plenty more:
- “What is the statistical evidence linking climate change to co2?” (http://www.thenakedscientists.com/forum/index.php?topic=15086.msg352828;boardseen)
- “Is Carbon Dioxide the real cause of an increase in Gobal Warming?” (http://www.thenakedscientists.com/forum/index.php?topic=37534.0)
- How can a small change in CO2 make a large change in climate?” (http://www.thenakedscientists.com/forum/index.php?topic=38247.0)
- Science News says “Greenland ice gives us the best view of the climate so far” (http://www.thenakedscientists.com/HTML/content/news/news/1411/).
- Science Articles says “Britain and China collaborate on climate change studies in the Arctic” (http://www.thenakedscientists.com/HTML/articles/article/internationalpolaryear20079/). 

As I said in my opening post on this thread, I came to this blog because of finding this article “Climate Change and Ice Cores” (http://www.thenakedscientists.com/HTML/content/interviews/interview/643/). These together persuade me that I had every reason to think that I was using the proper forum on the correct blog to elicit an answer.

As for my being

quite close to sounding querulous here

I first raised my simple question about collision v kinetic diameter (see the very first paragraph of the opening comment on this thread) over a year ago on the “Richard Alley at AGU 2009: The Biggest Control Knob” (http://chriscolose.wordpress.com/2009/12/18/richard-alley-at-agu-2009-the-biggest-control-knob/) blog of science student Chris Colose and have discussed it at numerous blogs since. If you Google - "Pete Ridley" "kinetic diameter" – or "Pete Ridley" "fractionation" you’ll find more than enough examples.

As you are probably aware I have been very disappointed with the level of scientific expertise that has been displayed here with regard to my question. I came here with great hopes that at last I had found a blog where scientists would be able to answer it but after 7 days, 55 replies and 923 views I am no nearer getting an answer.

The impression that I get is that your latest comment was made out of frustration with yourself that so far you have been unable to provide anything that helps to answer my simple question. My suspicion is that it requires expertise that you don’t have. If that is the case then just say so. I understand BenV to have acknowledged that The Naked Scientists cannot answer my question. There is no shame in ignorance and none of us, not even the most brilliant, are in a position where we can scoff at others because of it.

I’ve tried to elicit an answer from scientists at Cambridge, Otago, Wisconsin, Johns Hopkins, Texas, Suffolk County, etc. without success. Now I’ll have to try elsewhere, perhaps University College London’s Environmental Change Research Centre can do better than any of these.

My only agenda is to get an answer to my simple question.

Best regards, Pete Ridley

[yor_on]

Sorry, but I honestly start to wonder if you're trolling here. And saying that no scientist can answer your question is a rather big bite to ingest

I would say that the evidence regarding the way the ice-cores correlate to other sources make them quite acceptable.  Now it suddenly seem to be a environmental question again, in which case my responses should give you some ideas why I expect it to be so, if you now read them? Before dismissing them? But if it will turn out to become a physics/chemistry/geology question again in your next post, well, then I'm afraid I will continue to point out that this sub-forum is about Environment.

Maybe you should take it up with some university near to you?
Possibly they can help you,  or NOOA?
Otherwise I suggest Dept. of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology

They seem to have a very good reputation, and if your question is as important as you seem to feel it to be, I'm sure they too will recognize its importance. Good luck.
==

Peter, I don't know what familiarity you have with chemistry but maybe this book will give you some ideas how to continue your research? Chemistry: The Practical Science.

And maybe you will find this one of interest. It puts some weight to your thoughts. I'm not saying that it has to do with your question, but it might have an importance. And it could be worth checking up..

"The team's calculations are based on a probabilistic analysis of climate variation between the years 1050 and 1800 - that is, before the Industrial Revolution introduced fossil carbon into the atmosphere. Using 200,000 data points, the study - believed by Nature to be the most comprehensive of its kind so far - compared the Antarctic ice core record of trapped CO2 bubbles with so-called proxy data like tree rings, which are used to estimate temperature changes.

The most likely value among their estimates suggests that for every degree Celsius of warming, natural ecosystems tend to release an extra 7.7 parts per million of CO2 to the atmosphere (the full range of their estimate was between 1.7 and 21.4 parts per million). The oceans' ability to absorb CO2 figures strongly into the debate This stands in sharp contrast to the recent estimates of positive feedback models, which suggest a release of 40 parts per million per degree; the team say with 95% certainty that value is an overestimate.

"This is a valuable paper that helps to constrain certain feedback components for the past," said John Schellnhuber, director of the Potsdam Institute for Climate Impact Research. "However, it is probably not suited for extrapolation into the future and it does not cover the really interesting processes like anthropogenic activation of permafrost carbon or methane clathrates." "

The discussion on Realclimate I guess that you might see them as the 'enemy', but they're foremost Climatologists Peter. So take a look and see what they, and you, think.

[Pete Ridley (OP)]

Hi Yor_on whether or not anyone here regards me as a troll or anything else is not important. What I see as being important is that scientists can give a convincing answer to a question that is fundamental to the CACC doctrine, i.e. the manner in which atmospheric CO2 content has varied in the past. Scientists like Drs Alley, Severinghaus, Huber, Bender, etc. regard measurements of gas composition in residual air recovered from ice as being the “Gold Standard” but I question whether this is in fact simply “Fools Gold”. I question this as a layman and have every right to do so, however, I have never said, as you claim,

that no scientist can answer your question

What I have said repeatedly is that no scientist has given me a convincing answer to my question posted here, which is a lot different from can answer.

As I have been unable to get a satisfactory answer to my question here or elsewhere I have indeed today E-mailed several professors at University College London, including

Dr. Tim Atkinson, Professor of Environmental Geochemistry .. research interests include earth and environmental sciences, centring around the applications of chemistry and physics to problems in hydrology, hydrogeology, Quaternary geology and palaeoclimate, and geomorphology ..

(http://www.ecrc.ucl.ac.uk/index.php/content/view/375/94/).

I also had an interesting chat with

Dr. Euan Nisbet, Professor of Earth Sciences, Department of Earth Sciences, Royal Holloway, University of London

(http://pure.rhul.ac.uk/portal/en/persons/euan-nisbet%282ff4ba1e-64af-450c-b39d-eb64b7f809d1%29.html). Although he acknowledged that he is not an authority on this subject he has sent me a couple of papers by Etheridge et al. and has recommended that I talk with Dr. Eric Wolff, EPICA. Isn’t that a surprise. That might well be the same Dr. Eric Wolff who chatted with Naked Scientists Dr Chris Smith and Dr Helen Scales on 21st Jan 2007 (just ahead of the publication of the IPCC’s scare-mongering AR4 SPM) about “Alternative Energy, Climate Change and Carbon Capture” (http://www.thenakedscientists.com/HTML/podcasts/show/2007.01.21/). Oh yes, and the same Dr. Eric Wolff who was interviewed by Chris at the same time on the subject of “Climate Change and Ice Cores” (http://www.thenakedscientists.com/HTML/index.php?id=40&tx_naksciinterview_pi1[showUid]=643&cHash=7faa6cce3f&table=tx_naksciinterview_interviews) and attracted me to this blog in the first place.

I have sent a message to Dr. Wolff and look forward to chatting with him.

You may recall that when I was pointing out the differences in collision and kinetic diameter of the molecules of various atmospheric gases on 14th April @ 21:38:13 I said to Wiybit

Note the difference for CO2. Also note the size of He and think of the He-filled party balloon compared with one that you and I might blow up ourselves – which stays up the longest and why?

He has a smaller kinetic diameter than the molecules of the gases in air coming out of out lungs, which is mainly N2 and O2.

As we already know, CH4 has a smaller collision diameter (0.38nm) than CO2 (0.39nm) but a much larger kinetic diameter (still 0.38nm) than has CO2 (now 0.33nm). This would suggest that if collision diameter is relevant with regard to molecule movement through nanopores then there should be little difference between the two gases whereas if kinetic diameter is relevant then CO2 should move more readily than CH4

Professor Nisbet provided me with some anecdotal evidence of the movement of smaller molecules through nanoporous material similar to the party balloon evidence. If you look at the link to his credentials you will see that he has been involved in research with two of the gases, CO2 and CH4. He advised that he has found when transporting the two gases around that CO2 is much more problematic than CH4 and has to be carried in heavy steel containers. He likened CO2 to a needle due to its linear O-C-O molecular structure (http://www.eou.edu/chemweb/molmodel/mmp4d1.html). On the other hand the CH4 molecule has a tetrahedral structure. For anyone interested there is an excellent description and animation of these (and other) structures on the Oklahoma State University’s Department of Chemistry site (http://intro.chem.okstate.edu/1314f00/lecture/chapter10/vsepr.html).

My study of chemistry stopped at A-level 35 years ago so thanks for the heads up about “Chemistry: The Practical Science” (http://books.google.co.uk/books?id=VfcKIManfkUC&printsec=frontcover&dq=chemistry+the+practical+science+media+enhanced+edition&source=bl&ots=CXTSWgDBgd&sig=M1SzmDCo67bprWuJDZXra32cRSY&hl=en&ei=rESvTZTMDsHG8QOXs5yQDw&sa=X&oi=book_result&ct=result&resnum=9&sqi=2&ved=0CFIQ6AEwCA#v=onepage&q&f=false). I have done a search and cannot find any reference to collision or kinetic diameter although it does give a brief mention of zeolites on page 310, describing what appears to be a similar process to what I hypothesise occurs in the deep firn. You may recall that on 18th April @ 10:04:48 I referred Wiybit to a patent that says

.. separation on size is possible, when the components to be separated are small enough in kinetic diameter to migrate through the zeolite pores and the components from which they have to be separated have a kinetic diameter that is too large ..

Professor Nisbet, who has relevant expertise in this area, recommends “"Mathematics of Diffusion" by John Crank, Professor of mathematics at Brunel University from 1957 to 1981 (http://www-history.mcs.st-and.ac.uk/Biographies/Crank.html) so I’ll try the library for a copy (maybe some kind person will buy me a copy for my birthday).

Thanks for reminding me about that Jan 2010 BBC article “Temperature and CO2 feedback 'weaker than thought'” as I had forgotten about Professor Brian Hoskins, a climate expert from Imperial College London. I’ll drop him an E-mail tomorrow.

Regarding Realclimate and your claim that

they're foremost Climatologists

there are those who have argued that they are not climate scientists but software engineers helping scientists to construct and tweak their models. Because I am discouraged by their membership of the “Hockey Team” I look for less biased sources.

I have to say that I do appreciate that you are doing what you can to help me find an answer to my question.

Best regards, Pete Ridley

[yor_on]

Good on you Peter. The study I referred you too is somewhat confusing in that it assumes that there will be a reduction of CO2 instead of an addition, at least as they have found statistically. I'm not sure how this fits with how you view it? Maybe it does. It is still a discrepancy and as such worth looking into. When it comes to Realclimate I find them totally professional myself, allowing both sides a fair debate, as far as I've seen.

As we both seem to agree on that TNS can't take you any further for the moment, I will allow myself the liberty of locking this thread, for now. I'm sure that Ben will try his best to search for the specific expertize you hoped for, and finding it we will reopen it. And I'm as sure that you will continue your quest for truth.

Good luck.
==

[ericwolff]

I admit I did not wade through the entire thread, but as far as I can see the originator of this thread would be content if I can answer one key question: “why do palaeoclimatologists use collision diameter in preference to kinetic diameter when considering the migration of air molecules through firn and ice”?  For your information, I am an ice core scientist at the British Antarctic Survey, as mentioned by Pete Ridley in one of his posts above.

The underlying issue is whether we can believe that the air in bubbles in ice cores is an un-fractionated representation of the atmosphere.  In other words, when we crack open a bubble of air, does it contain exactly the relative proportions of different molecules as the air in the atmosphere.  Because some readers of this post will not have done the reading that the questioner has, I will first state some issues that the questioner has already got past in order to get to his more subtle question.

Firstly, of course molecules that are unstable will not be present.  Thus the photochemically produced radical OH is not going to be found in the air bubbles.  Secondly, the air is fully enclosed in ice (ie the ice becomes impermeable) only at a depth, typically 60-100 m depending on the site, and the air is sitting in a slowly diffusing column of firn until it is enclosed (typically taking 1-3 decades to reach the enclosure depth).  In this column, there is a small gravitational fractionation, which is sometimes corrected for (the correction is easily made for a given core by looking at the fractionation of 15N14N compared to 14N2, and is of order 1 ppmv for CO2).

However, from your comments, I think you are more concerned about whether there is a further fractionation at the final stages of enclosure, related to the size of the molecule – do some smaller molecules more easily escape enclosure leading to a fractionation?  Certainly such a fractionation can exist for some atoms and molecules: it is very strong for neon (Ne), noticeable for O2 and Ar (at the permil to 1 percent level) but the literature says that there is no fractionation for CO2 (or CH4) compared to N2.  This is, I think, the issue that is worrying you.

You are raising an interesting point about the underlying processes occurring at the depth where the air becomes fully enclosed in ice.  However, I must start by being precise about the question.  To my knowledge, no paper bases its declaration that CO2 is unfractionated on theoretical arguments about the diameter of CO2 (whether collision or kinetic).  Rather they base their conclusions on observations of CO2 in the firn just above full enclosure and the bubbles just below it.  Because it has the highest snow accumulation rate of any core where CO2 has been measured, the best core to look at is Law Dome, and in particular the paper by Etheridge et al (1996).  Their most direct evidence is achieved because just around the enclosure depth, the air is “locked-in” (ie no longer significantly diffusing), but some bubbles are closed while some air is still in a partly open space.  Thus it is possible to measure air that should be of identical age that is not yet enclosed (by pumping on the firn air), and that is fully enclosed (by cracking open air bubbles).  In their figure 2, Etheridge et al show samples they have measured in the firn air (circles) and in trapped bubbles at the same depth (triangles): they conclude that the difference is a random 1.3 ppmv, showing that the enclosure process does not affect the concentration.  This is a really direct and elegant measurement which shows that, at least at Law Dome, there is no fractionation of CO2 on enclosure.

One can supplement this direct evidence:
a) For pre-industrial ice, one gets the same concentration at several different sites in Antarctica, so the conclusion of no fractionation for Law Dome must be true of other sites also;
b) One gets an excellent overlap between measurements in the atmosphere at South Pole, and measurements in enclosed bubbles of the same age air at Law Dome (Etheridge et al 1996, Fig 3) - the same concentrations and trends are seen.

I suspect that what you have in mind is the papers by Severinghaus et al (2006) and Huber et al (2006).  In both these papers the authors discuss the fractionation that does occur for O2, Ar and other gases, and they appear to be able to make sense of their data using a model that depends on a size-dependent fractionation in which they use the collision diameter, and find a threshold of 3.6 Angstroms below which fractionation may occur.  I agree that one could imagine constructing a model in which the kinetic diameter is important (and because of it's non-spherical nature, CO2 has a smaller kinetic than collision diameter).  However, in such a model, Ar would be more fractionated than O2, whereas Severinghaus et al's data shows it is only one-third as fractionated; and as you are implying, CO2 would be somewhat more fractionated than either Ar or CO2, which the data of Etheridge shows not to be the case.  But again, I want to be really clear, while you can argue whether their model is right, the conclusion about CO2 is based on the data, and the data are clear that there is no fractionation of CO2 compared to N2 (within the measurement uncertainty, which is of order 1 ppmv).

I hope this is clear and does answer the question. The strict answer is that palaeo-climatologists do not use any diameter to form the conclusion that CO2 is unfractionated - they use the data.  They find that using the collision diameter in a model helps them to understand those data, but the conclusions about what happens do not depend on that, only on the data. I have added the relevant references below.  For more general readers, we (at BAS) recently produced a science briefing about ice cores, which you can read at
newbielink:http://www.antarctica.ac.uk/press/journalists/resources/science/icecorebriefing.php [nonactive]

References:

Etheridge, D. M., Steele, L. P., Langenfelds, R. L., Francey, R. J., Barnola, J.-M. and Morgan, V. I.: Natural and anthropogenic changes in atmospheric CO2 over the last 1000 years from air in Antarctic ice and firn, J. Geophys. Res., 101, 4115-4118, 1996.

Severinghaus, J. P. and Battle, M. O.: Fractionation of gases in polar ice during bubble close-off: New constraints from firn air Ne, Kr and Xe observations, Earth planet. Sci. Lett., 244, 474-500, 2006.

Huber, C., Beyerle, U., Leuenberger, M., Schwander, J., Kipfer, R., Spahni, R., Severinghaus, J. P. and Weiler, K.: Evidence for molecular size dependent gas fractionation in firn air derived from noble gases, oxygen, and nitrogen measurements, Earth planet. Sci. Lett., 243, 61-73, 2006.

Wolff, E. W.: Greenhouse gases in the Earth system: a palaeoclimate perspective, Philos. Trans. R. Soc. Lond. Ser. A-Math. Phys. Eng. Sci., 369, 2133-2147, 2011.

[imatfaal]

Great post Eric - I will check out your science briefing

[yor_on]

Beautifully put Eric, stringent and clear. We're pleased, both of me. That is, my royal persona as well as my more down to earth peasant, ahem. And yes, that was a joke. I'm only one, although looking in my mirror sometimes (mornings especially) I hardly recognize myself?

Hopefully it won't be the last time you write here, and I will follow that link.