About the reliability of ice cores…
Guest Post by Ferdinand Engelbeen
There have been hundreds of reactions to part 1 about the mass balance (http://wattsupwiththat.com/2010/08/05/why-the-co2-increase-is-man-made-part-1 ). Many respondents still are not convinced that the mass balance is a firm proof that the observed increase of CO2 in the atmosphere is human made. But there are more indications. Ultimately, any alternative explanation must fit all the observations. If the alternative hypothesis fails even only one of the observations, then the alternative is rejected. But before we start to look at more observations which support an anthropogenic cause, we need to address several misconceptions which fly around on the Internet, mainly on skeptic blogs… This part has a detailed look at the reliability of ice cores, which are quite important for our knowledge of the pre-industrial CO2 levels, but have been subject to a lot of critique.
Note that the ice cores only show CO2 levels back to about 800,000 years, but measurements may in the future be extended to over one million years. What is found in the ice cores is only relevant for the most recent period of our history and not for more distant geological time periods.
About the reliability of ice cores:
Some have objections to the ice core measurements, as these are regarded as the main reason for the “equilibrium” assumption of ancient CO2 levels. The only real problem in this case is the smoothing of CO2 levels. That depends on the snow accumulation rate, as it takes a lot of time to close all air bubbles in between the snow flakes. That happens at a certain depth where the pressure is high enough to transform the snow, then firn (densified snow still with open pores) into ice. The averaging happens partly because at first the firn pores are large enough to let the air in the pores and in the atmosphere exchange with each other, partly because some bubbles close early, others at a lower depth (thus contain air which is different in composition, “age”, than other already closed bubbles). The depth where this happens depends on the pressure from the layers above and the temperature of the ice. The time needed for full closure of all bubbles largely depends on the accumulation rate of snow at the place where the ice core is taken (or upstream if coring at a slope).
That makes that the average smoothing of CO2 levels is about 8 years (Law Dome 2 out of 3 ice cores, 1.2 m ice equivalent/year accumulation), some 21 years (the third Law Dome ice core, 0.6 m ice equivalent, see http://www.agu.org/pubs/crossref/1996/95JD03410.shtml unfortunately behind a pay wall…), some 570 years (Dome C, a few mm/year, see http://www.nature.com/nature/journal/v453/n7193/full/nature06949.html ) and everything in between. The Law Dome closing period of the bubbles was measured, while for Dome C one needed models to estimate the time resolution in the far past.
Thus the smaller the snowfall at a certain place, the longer it takes for the bubbles to fully close and the longer averaging one has. At the other side, the smaller the accumulation rate, the further we can look back in the past, as for the same depth of ice, there are many more years of snowfall.
The fact that the pores still are open over a long period, also means that there are differences in the age of the ice and the age of the enclosed gas. The age of the ice can be counted, as it simply is the result of ice formation from yearly snow accumulation where winter/summer snow density differences gives clearly distinguishable layers if there is sufficient accumulation. If, as depth increases, the pressure and/or flow result in layers that are near invisible, one may use several other methods like electro conduction or X-rays (see http://iopscience.iop.org/1742-6596/41/1/034/pdf/jpconf6_41_034.pdf ) to distinguish the layers/age.
Determining the gas age is not as easy. Over the years of accumulation of the snow/firn, the pressure builds up and the firn becomes more dense with decreasing pore diameter. That reduces the exchange of air in the pores with the air in the atmosphere, until the pores are too small to make any further exchange possible. If there has been considerable accumulation, as in the two fast Law Dome cores, at the depth of the first closing (about 72 meters) the ice is already 40 years old (40 layers), but the air has the average CO2 levels of less than 10 years ago, which makes the average gas age (including the average time for fully closing of all bubbles) about 30 years younger than the ice at the same depth. For the top layers, we have the advantage of direct measurements in the atmosphere for overlapping periods, which makes a comparison possible.
For cores with far less accumulation, the analysis is more problematic, as the difference increases with the reciprocal of the accumulation rate. During ice ages, there was less precipitation, thus increasing the ice age – gas age difference. The ice-gas age difference for the Vostok ice core is over 3,000 years. Be aware that the ice-gas age difference has nothing to do with the resolution of the CO2 levels, as these are in the bubbles themselves, but it makes a chronology of what happens between temperature (measured as dD and d18O proxy in the ice, see further) and CO2 levels (measured in the bubbles) more difficult to establish. But here also different techniques are used: diffusion speed is a matter of pore diameter, directly related to firn/ice density and densification speed is directly related to accumulation speed. This can be used to model the exchanges between air in the pores and the atmosphere.
The calculations to establish the gas age did fit quite well for the Law Dome ice cores, where besides ice age, the average gas age was established by measuring CO2 levels top down in the firn. That showed that the gas age at closing depth was less than 10 years old on average, but more importantly, the CO2 levels in the already fully closed bubbles and the still open pores were the same. For the low accumulation ice cores like Vostok, there is more discussion about the ice-gas age difference and different time scales were established…
The accuracy of the measurements in the three Law Dome ice cores for the same gas age is about 1.2 ppmv (1 sigma). Later works compared different ice cores for CO2 levels at the same average gas age. These show differences of only 5 ppmv, despite huge differences in average temperature (coastal -20°C, inland -40°C), salt inclusions (coastal), accumulation rate and resolution. There are a lot of overlapping periods between the ice cores, the resolution decreases with increasing length of period (from 150 years – for 2 of 3 Law Dome ice cores – to 800,000 years – Dome C), but even so, the measurements (done by different labs of different organizations) show a remarkable correspondence for the same average gas age. This is a nice indication that the CO2 levels of the ice cores indeed represent the ancient levels.
Data over the past 10,000 years of average gas age in ice cores from:
http://www.ncdc.noaa.gov/paleo/icecore/current.html
As result, for the past 150 years (Law Dome) we have accurate data with a reasonable resolution. The cores average the CO2 levels over 8 years, so any peak of 20 ppmv during one year or 2 ppmv difference sustained over 10 years would be observable. For older periods, the resolution is less and the averaging applies to the full period of resolution (about 570 years for Dome C).
The visual correlation between temperature and CO2 levels in ice cores is well known to everybody, as that was used by Al Gore and many others, although he forgot to tell his audience that the CO2 levels lagged by some 800 years during a deglaciation and many thousands of years at the onset of new glaciations:
Data from the Vostok ice core via:
The temperature is derived from dD and d18O proxies in the ice. dD means the change in the deuterium/hydrogen ratio measured in the water molecules of the ice and d18O is the change in 18O/16O ratio of the water molecules in the ice. Both heavier isotopes of hydrogen resp. oxygen increase in ratio to the lighter ones, when the ocean temperature, from where the precipitation originates, increases. Thus the change in ratio is an indication of the ocean temperature changes. For coastal ice cores, that indicates the temperature changes in the nearby Southern Ocean, while the deep inland cores receive their precipitation from the more widespread SH oceans, thus representing the temperature changes of about the whole SH. The NH ocean temperature changes are more or less represented in the Greenland ice cores, which show similar changes (over the last about 120,000 years), but with some differences in timing and more detailed extreme events (like the Younger Dryas).
There is a remarkable near-linear ratio between ice core CO2 and the temperature proxy record in the same core over 420,000 years of Vostok. Work is under way to confirm this ratio in the 800,000 years of Dome C (for the overlapping period, the CO2 levels are already confirmed similar): about 8 ppmv/°C:
Data of the Vostok ice core from NOAA, temperature proxy indication shows zero at current temperature. From:
http://www.ncdc.noaa.gov/paleo/icecore/current.html
The spread in temperature/ CO2 data, mainly at the high side, is from the long lag of CO2 levels which remain high for thousands of years at the end of a warm period, while the temperature is dropping back to a minimum. The 8 ppmv/°C is not absolutely right, because temperature at best represents a hemispheric ocean temperature, but not far off, as the pCO2 in seawater dependency of temperature shows about 16 ppmv/°C. But besides pCO2 of seawater, other land and (deep) ocean items also play a role.
This all is an indication that temperature is not the cause of the sharp increase of CO2 in the last 150 years, as that wouldn’t give more than 8 ppmv (or 16 ppmv based on ocean solubility) increase with a maximum 1°C temperature increase since the depth of the LIA, while the current increase is over 100 ppmv.
Be aware that, besides some fractionation of the smallest atoms/molecules (not of CO2), and a small fractionation of isotopes, the bubbles still reflect the ancient atmosphere as it was. Ice core CO2 thus is not a proxy but a direct measurement, be it smoothed, of what actually happened in the (far) past.
The objections of Jaworowski:
What about the objections of Jaworowski against the reliability of ice cores (http://www.warwickhughes.com/icecore/ )?
Jaworowski assumes that CO2 “leaks” via cracks in the ice, caused by the drilling and pressure release of the deep core ice. But how can they measure 180-300 ppmv levels of CO2, when the outside world is at 380 ppmv? If cracks (and drilling fluid) are found in the ice, that would show levels which were too high, compared to other neighbouring layers, never too low.
The formation of clathrates (solid forms of O2, N2 and CO2 with water at very cold temperatures and high pressure) depletes CO2 levels, according to Jaworowski. This is well known in the ice core world. Therefore they allow the ice cores to relax up to a year after drilling. Moreover: O2 and N2 clathrates would decompose first, thus escaping as first via microcracks (as Jaworowski alleges). This would lead to too high CO2 levels, not too low.
Jaworowski accuses Neftel of “arbitrary” shifting the Siple data with 83 years to match the ice core CO2 with the Mauna Loa data. But the page from Neftel’s report ( http://www.biokurs.de/treibhaus/180CO2/neftel82-85.pdf ) contains two columns in the table: the counted ice age and the calculated gas age, the latter based on porosity measurements of the firn. Jaworoski used the age of the ice, not of the air bubbles, to base his accusation on, which is quite remarkable for a specialist in these matters. CO2 is in the air, not in the ice and the average age of the gas is (much) younger than the ice where it is enclosed. Neftel even made specific remarks about the gas age, which was compared to the South Pole atmospheric data, to confirm the average age of the gas bubbles at depth:
If the 328 p.p.m. measured at a depth of 68.5 m.b.s. [note: meters below surface] is matched with the atmospheric South Pole record, the mean gas age is 10 yr, corresponding to a difference between mean gas age and ice age of 82 yr, which lies in the above estimated range. The difference is used in calculating the mean gas age for all depths.
That the CO2 concentration measured on the subsequent samples from 72.5 and 76.5 m.b.s. corresponds with the atmospheric South Pole record justifies this age determination…
This clearly indicates that Neftel based his gas age estimate on firm grounds and there is nothing arbitrary in “shifting” the data, as there was no shifting at all. Thus for the Siple ice core, the ice age – gas age difference is about 82 years (Neftel estimated 80-85 years) for an average gas age resolution of about 22 years in this case.
Many of the objections of Jaworowski were answered by Etheridge (already in 1996) by drilling three cores at Law Dome, with three drilling methods (wet and dry), using different materials for sampling, avoiding cracks and clathrates, allowing a lot of relaxation time and measuring the CO2 levels top down in firn and ice. No difference was found in CO2 levels between firn and ice at closing depth and there is an overlap of some 20 years of the ice core CO2 data with the South Pole data:
Figure from Etheridge e.a.: http://www.agu.org/pubs/crossref/1996/95JD03410.shtml
See more comment and further links about Jaworowski at:
http://www.ferdinand-engelbeen.be/klimaat/jaworowski.html
The “corrections” of J.J. Drake:
JJ Drake (http://homepage.ntlworld.com/jdrake/Questioning_Climate/userfiles/Ice-core_corrections_report_1.pdf ) claimed to have established that the CO2 levels needed a correction for the ice-gas age difference. The result of the “correction” is that the CO2 levels are much higher with little variation and the very good correlation with temperature vanished. This conflicts already with our knowledge of the influence of temperature on CO2 levels in current times…
Even so, the “correction” might be all right, but the reason he provided has no bearing in any physical relationship. He makes the basic mistake of conflating a good correlation with a causation: The error is of the kind:
A causes B and shows a good correlation.
A causes C and shows a good corelation.
Thus B causes C, because there is a good correlation between the two. But that correlation is completely spurious, as there is not the slightest physical connection between B and C.
The explanation for his observation is quite simple:
Temperature (“A”) causes the ice-gas age lag (“B”), as temperature is directly connected with humidity of the atmosphere, thus influences the amount of snowfall, thus the accumulation rate and as reciprocal the speed of closing the bubbles: higher temperature, higher snowfall, smaller ice-gas difference.
Temperature (“A”) influences CO2 levels (“C”) directly: higher temperature means higher CO2 levels.
Because the previous two results have a high correlation with temperature, that gives that the ice-gas age difference and the CO2 levels also show a high correlation, but there is no physical mechanism that shows any direct or indirect action of ice-gas age difference on CO2 levels or vice versa. It is a completely spurious correlation, without any causation involved, but both share the same cause. Any “correction” of CO2 levels found in ice cores based on the correlation with ice-gas age difference is meaningless.
Migration of CO2 in ice cores
Ice shows a thin layer of unstructured (liquid waterlike) water molecules near the surface of the air bubbles. Some CO2 may dissolve in this layer, but that is not a problem at measurement time, as measurements are made at low temperature under vacuum, effectively removing all CO2 from the opened bubbles in the crushed ice, while removing any water vapor as ice over an extra cold trap. Water in-between the ice crystals is very unlikely, as there is still the direct influence of ordered structural ice from both sides.
Migration in even the oldest cores is no real problem. The recent fuss about “migration” speed was deduced from the Siple core, based on layers where remelting occurred, something not seen in any high elevation ice core like Vostok or Dome C. It remains to be seen to what extent the Siple Dome results are applicable to other ice cores.
But if there was even the slightest migration of CO2, that would affect the ppmv/°C ratio of the above Vostok CO2/temperature graph over time: the proxy temperature indication is fixed in the ice, while CO2 is measured in the gas bubbles. If there was any substantial migration of CO2, the ratio between CO2 and temperature over warm and cold periods would fade away over the recurrent 100,000 years of time difference between the warm periods, but that is not observed.
Conclusion
The ice cores are a reliable source of knowledge of ancient atmospheres, if handled with care. The resolution heavily depends of the accumulation rate, with as result that the data measured in enclosed air bubbles are smoothed, ranging from 8 years for the past 150 years to near 600 years for the past 800,000 years.
I would like to see some speculation on co2 causing arming from the 800000 year records, see the graphs above.
It should be possible to deduce cause-effect from the peaks on the graph.
Really, it should be a no-brainer for an able statistician to sort out if it is the warming that causes rise in co2 or vice versa?
The records have lots of peaks and stuff that ought to be possible to correlate, and those that dont should indicate who is pushing who, and how much.
Is there not even any good hypothesis on the nature of casuality?
Jeff M says:
August 21, 2010 at 11:11 am
A few people have commented on plants shutting down at low CO2 levels. Are there any natural, but non-biological or non-plant processes that reduce atmospheric CO2?
==========================================================
Yes, the formation of limestone is one.
He could be right, or he could be wrong.
@Deech56 says: August 21, 2010 at 5:48 am
“And Martin Brumby wrote: “OK, there is SOME evidence temperatures have risen over the last century.
There is a fair amount of evidence that the trace gas CO2 levels have risen over the last century. ”
Glad to see you agree with the consensus on some basic points. You did forget the other important point, though, that CO2 is a greenhouse gas. ;-)”
No, didn’t forget that.
YOU forgot that water vapout is a far more plentiful and powerful greenhouse gas than CO2.
And that the “greenhouse” effect of CO2 is logarithmic and is probably already saturated at current levels.
And that the only way the computer models can make CO2 & temperature “fit” is by assuming large positive feedbacks for which there is absolutely no evidence (unless you take the fact that every modeler has to assume basically the same thing to be “evidence”).
And you certainly forgot that the alarmists have trotted out literally hundreds of scaremongering “disaster” tipping point press releases to try to bolster their collapsing theory and that all of these scares have been shown to be far fetched or completely bogus.
And you definitely forgot that it is the alarmists who are insisting on the urgent need to spend trillions on “low carbon” energy “solutions” that don’t actually work in the real world.
And perhaps you haven’t even realised that “consensus” is a term that belongs in politics, not in science. And that the “war on global warming” is, in reality, a war on the poor.
winterkorn says:
August 21, 2010 at 9:07 am
‘If it is true that human CO2 production is only 4% of total production, then common sense indicates that a relatively small change in the other 96% (which must be biological, for the most part) could overwhelm any human change. For example a few percent change in CO2 production from the huge reservoirs of biologically available carbon (rotting vegetation, peat, coal, oil seeps, etc) could produce big changes in the overall flows in the Earth’s CO2 cycle.’
So, so, so true. The noise completely obliterates the signal across the entire spectrum, which is why <a href="http://wattsupwiththat.com/2010/08/20/engelbeen-on-why-he-thinks-the-co2-increase-is-man-made-part-2/#comment-462633" you do not see any broad correlation between human inputs and actual CO2 measurements. I have done the analysis. There are no discernible overlapping periodicities between human production and the measurements.
Ferdinand is convinced of correlation merely by the fact that two time series with slope and same-signed curvature are scale similar over a short time period. Like that is some incredibly unlikely thing, rather than virtually assured! He just doesn’t get functional analysis, and the necessity of observing ALL the base functions appearing in both the input and output.
‘The huge increases in CO2 during some interglacials in the past came from somewhere, as yet not known with certainty.”‘
And yet, Ferdinand summarily dismisses the idea that there can be any sources other than human generated, even though this simple statement proves that there are!
‘So long as these sorts of issues remain, the truth about effects of human production of CO2 should be considered as in some doubt.’
A very good post, winterkorn.
Mike Jonas says: August 21, 2010 at 5:15 am
quote
Stephen Wilde : “Then why the absence of any irregularities in the rising CO2 slope that correspond with irregularities in human CO2 emissions ? There should be such irregularities within a steadily increasing angle of curve but neither are present.”
A good question.
I made my point earlier rather briefly. I should elaborate a bit :[]
What I did find was that I could not get anything like a match to the CO2 increase by trying to ascribe it to warming oceans, THC volumes, etc. I was therefore unable to contradict F.E.’s conclusion, and I felt that having done the work I should admit the result.
The incredibly close correlation between temperature (T not dT) and annual change in CO2 shows incontrovertibly (to my mind) that temperature affects CO2 levels. The same applies to the long term record (CO2 lagging by a few hundred years). It is also obvious IMHO that ENSO affects CO2 levels. But all the analyses that I did led me to the conclusion that although these factors did affect CO2, they could not explain the rise in CO2 over the last several decades – that in the absence of fossil fuel emissions, CO2 levels would still have risen but not by much. It is possible of course that I missed something.
Hopefully someone will answer your question eventually. I can’t.
unquote
I’ve been thinking. The change in CO2 levels are a response to a change in equilibrium — this is why I found Ferdinand’s argument about mass balance so unconvincing. Something has disturbed the equilibrium between uptake and production. Once that is accepted then all falls into place.
Somewhere above, Ferdinand asks for another theory which explains all the facts. I’ll see what I can do.
JF
Ferdinand Engelbeen says:
August 21, 2010 at 7:28 am
e_por says:
August 20, 2010 at 11:23 pm
<>
Both the human emissions and the increase in the atmosphere are increasing slightly eponential, and the increase in the atmosphere follows the totallity of the emissions with an incredible fixed ratio:
<>>
My fear is that too many skeptics are defending the undefendable: that humans are not the cause of the rise. That is a point where the “consensus” is rock solid. That undermines their credibility on other points where the “consensus” is far from certain.
1. When there were large changes in fossil fuel usage such as the 1970’s fuel crisis – there is still a monotonic rise in the CO2 record. Therefore the human input to the rise must be very small. Are you suggesting that Nature somehow adjusts to fill in what humans do not produce?
2. Skeptics are not ‘defending’ anything – they are being skeptical about your assumptions and conclusions – that is what science does. Similarly –
3. In science the ‘consensus’ is almost always WRONG. Newtonian ideas on gravitation were the firmly held consensus view. Phlogiston Theory was the consensus view. People win Nobel prizes for breaking with the consensus view. If you want to rule by consensus then become a politician – you do not belong in science.
To my knowledge, there has never been any thorough validation of the accuracy of the methods used to measure CO2 in ice core bubbles. Instead, the studies done to address this mistakenly confuse precision with accuracy. If anyone knows of a reference that does validate accuracy of ice core CO2 measurements, then please let me know.
My guess is that crushing of ice core samples creates a thin water film (much like that created under the blade of an ice skate) that absorbs CO2.
tonyb and Fred Haynie:
“For a different take on the ice core data read
http://www.kidswincom.net/climate.pdf
and decide which is more consistent with physics and real world observations.”
I like that piece of work very much and would support it forming a thread here if the author agrees.
As far as I can tell every aspect of it would fit nicely with my New Climate Model.
Ferdinand Engelbeen : “Both the human emissions and the increase in the atmosphere are increasing slightly eponential, and the increase in the atmosphere follows the totallity of the emissions with an incredible fixed ratio:”
http://www.ferdinand-engelbeen.be/klimaat/klim_img/temp_co2_acc_1900_2004.jpg
Actually, to my eye your graph shows greater correlation between temperature and CO2 than between emissions and CO2.
There is clearly a very strong relationship between temperature and CO2:
http://members.westnet.com.au/jonas1/deltaCO2vsTemp.JPG
and the spike at the 1998 El Nino shows that it is CO2 responding to temperature.
Note : The CO2 graph shows 12-month change in CO2 concentration, plotted at the mid-point of the 12-month period. It could be argued that it should be plotted at the end point of the 12-month period, in which case there would be an obvious timelag from temperature to CO2 change.
I have my own graph of emissions (EIA), temperature (UAH LT) and annual CO2 changes (Mauna Loa):
http://members.westnet.com.au/jonas1/EIACO2EmissionsAndTemperature.jpg
It is annual not monthly because the emissions data is annual.
It clearly shows that annual change in CO2 concentration relates far more strongly to temperature than to emissions.
But in spite of all this, I still can’t establish that the overall trend in CO2 concentrations is driven more than temperature than by emissions. But then, as I said before, maybe I have missed something.
Ian W says:
August 21, 2010 at 1:16 pm
1. When there were large changes in fossil fuel usage such as the 1970′s fuel crisis – there is still a monotonic rise in the CO2 record.
———————-
What large changes?
http://en.wikipedia.org/wiki/File:Global_Carbon_Emissions.svg
http://cdiac.ornl.gov/ftp/ndp030/CSV-FILES/global.1751_2007.csv
The total emissions in the 1970s fell by less than 10%. That means that the rate of growth of atmospheric CO2 will fall by less than 10% for a few years. Good luck in detecting that by eye.
At noon today the temperature on my stoep was 21 degrees C. Try as I might I have been unable to extrapolate from that what the temperature was today at Vostok. It seems to me that if we had a measure sure, certainly dated at 21st August, A.D. 800,000, telling us what the CO2 level was for Vostok at, say 1 meter above the ice, we would be unable to extrapolate from that the C02 level one meter above the land where my stoep now stands, on that same day. As my stoep is very close to a very warm sub tropical ocean, with the consequent vigorous biomass, I would be very surprised were I to find that atmospheric concentration here was not substantially higher than it was at Vostok.
Sorry, that should read, ’21st August, 800,000 B.P.’
“The ice cores are a reliable source of knowledge of ancient atmospheres, if handled with care. The resolution heavily depends of the accumulation rate, with as result that the data measured in enclosed air bubbles are smoothed, ranging from 8 years for the past 150 years to near 600 years for the past 800,000 years.”
Even if one was to stipulate to all the points you made in your post, the fact would remain that for the vast majority of the ice core records the temporal resolution of individual observations of CO2 is four to five times the length of the instrumental temperature record and much more than an order of magnitude times the the length of the Keeling record. As you pointed out, at best, each observation provides only a thoroughly homogenized long term average which can tell us nothing about whatever fluctuations, radical or minor, may have been occurring in the levels of atmospheric CO2 over the time span of the observation.
Even if every one of the multitude of objections to the ice core record should prove to be completely unfounded, which despite your efforts hasn’t happened yet, what we are left with is a dubious long term average for paleo CO2 that really tells us nothing meaningful about the present short term pertubations.
Aren’t there some, (or at least one), ice cores that indicate CO2 has been increasing since the ancient Egyptians about 4,500YA?
Correct me if I’m wrong.
DaveE.
“what we are left with is a dubious long term average for paleo CO2 that really tells us nothing meaningful about the present short term pertubations.”
Much like dendroclimatology then.
It is likely that ALL the available proxies are too coarse and/or insensitive to capture routine natural climate and CO2 variability on timescales less than 500 years.
For any proxy that fails to clearly pick up the MWP and the LIA that coarsness or insensitivity will apply for periods even longer and so such proxies may perhaps be wholly useless for guaging the extent and frequency of natural variations.
So our models and assumptions rely on compromised data that is wholly inadequate as a basis for any sort of comparison with the far more accurate modern methods of measurement.
Thus I prefer a clean slate whereby we start from first principles, create a hypothesis that appears to fit recent observations and progress by seeing how well or how badly it fits ongoing observations. If incorrect in any material particular it can be adjusted as necessary to maintain compliance with reality.
In theory that is what our models do but thet are now so replete with inadequate proxy data and flawed basic assumptions that we should scrap them all and start again using only the best recent directly observed data and adding to that with new data from the real world as time goes by.
Time for a completely fresh start. Preferably with fresh personnel.
I’d like to support Stephen Wilde and TonyB who would like to see Fred Haynie’s superb “citizens science paper” elevated to its own post here.
I like Ferdinand personally. Scientifically I’m tired of battling with this admirably indefatigable fighter. I still feel he is wrong and unwilling to look at material that disputes his well-thought-out hypothesis – much of which has appeared in the blogosphere. He’s battled with Tom Segalstad whom I trust better. He debunks Jaworowski on the strength of the classically awful blog SomeAreBoojums. For defence of Jaworowski, see this rendering of what I regard as Jaworowski’s most important paper, written just before despair at the corruption of science diluted his ability to stick to clear pure science without political comment.
I’d like to see Ferdinand take on Fred Haynie – truly a clash of titans. I think Fred’s science goes deeper, and supports Segalstad and Jaworowski. And thank goodness, Fred’s presentation is beautiful and clear.
stumpy says:
August 21, 2010 at 2:09 am
You have still failed to answer one key point, do co2 levels at Antarctica represent the global level? I doubt it very much given the temperature of the oceans there, and recent satelite data has confirmed its not “well mixed” as was assumed. Can you comment regarding this argument? Is there any evidence that co2 levels at Antartica represent the global average at all times in history? Is they dont, they you cannot use it for mass balance without knowing its relation to global levels and at various times i.e. interglacial, and ice age. I doubt this is possible with any certainty – therefore, great uncertainty still exists.
CO2 levels at Antarctica, Mauna Loa or Barrow (and many other places away from local/regional sources and sinks), spanning from near the North Pole to the South Pole are within 5 ppmv for yearly averages. The largest variation within a year is the seasonal variation, mainly in the NH. The largest difference in yearly averages is a lag between the NH stations and SH stations, which points to a (continuous growing) source in the NH and the ITCZ which hinders the exchanges of air masses between the NH and the SH, including CO2 (and dust). See:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/co2_trends.jpg
Thus any lag of such order (about 12 months) is of little interest for ice cores which average over 8 to 600 years…
I haven’t see yearly averages of the satellite data yet, most give only monthly averages which are influenced by the seasonal variation.
As far as I can see, the ice cores show reliable, but averaged levels of past atmospheric compositions.
kwik says:
August 21, 2010 at 3:13 am
A very interesting post. Thank you Ferdinand.
Ferdinand, what is your comment on this list here;
http://c3headlines.typepad.com/.a/6a010536b58035970c0120a5e507c9970c-pi
Off topic here, but the authors are looking at the residence time, that is how long a certain molecule resides in the atmosphere in average before being captured by vegetation or oceans. As about 150 GtC/year flows in and out the atmosphere from/to other reservoirs, the residence time, based on the througput of 150/800 = 18.8%, will be slightly over 5 years. This is what most of the items on the list show. That is what dilutes the atmospheric content e.g. of 14C from atomic bomb testing.
Not so for any increase of CO2 in the atmosphere (whatever the source): de decay rate is how fast an excess amount of CO2 injected into the atmosphere is getting back to the “normal” equilibrium, that is based on the difference between natural inputs and outputs, which is nowadays about 4 GtC sink capacity per year. Quite a difference with the 150 GtC throughput of the residence time.
Peter Dietze shows some 38 years half life time for the decay rate:
http://www.john-daly.com/carbon.htm
Thus in general: the residence time and the decay rate are two totally different items and have (near) nothing in common.
The IPCC shows a mix of different decay times, some of them hundreds of years and some near permanent, based on the “Bern model”, but I don’t think that that needs to be discussed here.
joshua corning says:
August 21, 2010 at 3:17 am
With the different characteristics of the ice layer…some layers being created during warm periods and other being created during colder periods it is possible to create a natural forward osmosis process with the differing layers of ice in which not only the concentration of the CO2 could be preserved but in fact the CO2 concentrations could be exaggerated. In other words the concentration of CO2 could be somewhat uniform through the ice but as time passes the differing layers allows H20 molecules to move yet keep the CO2 bubbles in the same place. Over time, like 800 years of time, the slight variations in CO2 concentrations could be exaggerated.
Interesting theory, but I don’t think that the differences are large enough between thousands of layers (a deglaciation takes some 10,000 years) to make this happen. And one would expect differences between the cycles, each 100,000 years apart, over time. And one would expect difference between ice cores with large differences in accumulation rate… The difference in CO2 levels are substantial (some 100 ppmv) between an ice age and an interglacial.
We have been discussing this issue in Climate Sceptic.yahoo group with Ferdinand, and he has taken with Haynie. We have not arrived at any conclusion. The discussion is almost over (I hope) so I wrote my last question:
“Risking to going back to the drawing board in ths discussion, I would like to point out some obvious thing. Sorry for throwing a brick at your window.
Dear Ferdinand,
You said (bold in uncertanties):
Humans add 7 GtC CO2 per year to the atmosphere,
nature removes 3.5 GtC per year from the atmosphere in different sinks.
The natural refresh rate of 150 GtC per year
replaces much if not all of the additional human
CO2 molecules by natural CO2 molecules.
As I understand (and all people here know) those figures are estimates, obtained through several long and complex procedures. If one or more of the original values used to calculate the result is not 100% accurate (and most of them are not), then due to the proverbial “butterfly effect” the result will be a succession of positive and negative feedbacks that can lead to weird results.
I also understand that that there is a lot of disagreement among experts in this matter, so my impression is that the 7GT CO2 emissions and 3.5 GT removal figures are not the real ones.
******************
I see too many trees in this matter, we are too close to them and that makes the forest difficult to see. Did I miss something in the issue?
Sorry I am late to this thread.
I would like to know the Argon/Nitrogen ratio through the core. It appears from Kellings work that the atmospheric Ar/N2 ratio is changing at the moment. This change would indicate a big change in the differential suitabilities of these gasses in the oceans.
Thanks, Mr. Engelbeen, for a thorough article and for your willingness to respond to many of the questions that have been raised. I continue to have a number of questions about the assumptions and methods involved in the conclusion that man is the cause of all (or the vast majority) of the increase in CO2 levels in recent decades. Nevertheless, this has been very informative, and your willingness to respond to questions in a calm manner and engage in discussion is very much appreciated.
Sorry, 3rd grade question, here:
Does ice at the poles where they drill these ice cores ever melt?
I ask because if we assume high levels of CO2 will cause warming and lead the ice to melt or just not form at all, would we ever see any evidence of those high levels of CO2 in the ice cores?
If this did actually happen and high CO2 melted the ice in the area where they drill these ice cores, you would see evidence in abrupt changes in CO2 levels. This is because the next layer of ice would be on top of and older layer that was melted down.
So, yeah, doesn’t seem like this would be a problem if that ice never melted.
Ferdinand,
A nice post. Wish I had half your enthusiasm and energy for arguing with non-sense. Keep up the good fight.