Breaking Hockey Sticks: Antarctic Ice Core Edition

Guest post by David Middleton


Source: NASA

Ancient air bubbles trapped in ice enable us to step back in time and see what Earth’s atmosphere, and climate, were like in the distant past. They tell us that levels of carbon dioxide (CO2) in the atmosphere are higher than they have been at any time in the past 400,000 years. During ice ages, CO2 levels were around 200 parts per million (ppm), and during the warmer interglacial periods, they hovered around 280 ppm (see fluctuations in the graph). In 2013, CO2 levels surpassed 400 ppm for the first time in recorded history. This recent relentless rise in CO2 shows a remarkably constant relationship with fossil-fuel burning, and can be well accounted for based on the simple premise that about 60 percent of fossil-fuel emissions stay in the air.

Today, we stand on the threshold of a new geologic era, which some term the “Anthropocene”, one where the climate is very different to the one our ancestors knew.

[…Blah, blah, blah…]


We’ve all heard variations of this meme… ad nauseumThey tell us that levels of carbon dioxide (CO2) in the atmosphere are higher than they have been at any time in the past 400,000 800,000 2.5 million 20 million years.   

This claim is generally based on the fact that Antarctic ice cores don’t indicate interglacial CO2 levels above 280-300 ppm at any point in the past 800,000 years or so.  While this is true, does it actually inform us that atmospheric CO2 levels could not have been well over 300 ppm during pre-industrial times?

WAIS Divide and the Effects of Resolution on Amplitude

West Antarctic Ice Sheet Divide Ice Core

On December 1, 2011, the West Antarctic Ice Sheet (WAIS) Divide ice core project, funded by the National Science Foundation, reached its final depth of 3405 meters (11,171 feet; over 2 miles), recovering the longest U.S. ice core to date from the polar regions. The 12.2-centimeter (4.8-inch) diameter cylinders of ice that make up the ice core contain uniquely detailed information on past environmental conditions during the last 68,000 years, such as the atmospheric concentration of greenhouse gases, surface air temperature, wind patterns, the extent of sea ice around Antarctica, and the average temperature of the ocean. Successfully retrieving the ice core is the culmination of an eight-year project to obtain a paleoclimate record from one of the remotest parts of the Antarctic continent.


In the WAIS Divide ice core, each of the past 30,000 years of snowfall can be identified in individual layers of ice, with lower temporal resolution records extending to 68,000 years before present. By allowing an examination of past climate at an annual resolution, the ice core record is helping scientists understand why climate can change abruptly and how climate may unfold in the coming century.

Other ice-coring projects have produced cores of lower temporal resolution, showing that the current level of atmospheric greenhouse gases, which is due to the burning of fossil fuels, is the highest in at least 800,000 years. The ice from the WAIS Divide ice core that is between 30,000 and 68,000 years old — while not containing records with annual resolution — contains a higher time resolution record than previous projects.


WAIS Divide

This comment caught my attention:

Other ice-coring projects have produced cores of lower temporal resolution, showing that the current level of atmospheric greenhouse gases, which is due to the burning of fossil fuels, is the highest in at least 800,000 years.

This raises the question: Are the ice cores “of lower temporal resolution” capable of resolving century-scale shifts in atmospheric CO2?  If not, then the conclusion “that the current level of atmospheric greenhouse gases, which is due to the burning of fossil fuels, is the highest in at least 800,000 years” is not supported.

The ice cores cannot resolve CO2 shifts that occur over periods of time shorter than twice the bubble enclosure period.

According to Neftel et al. (1988), CO2 fluctuation with a duration of less than twice the bubble enclosure time (equivalent to approximately 134 calendar yr in the case of Byrd ice and up to 550 calendar yr in Dome Concordia) cannot be detected in the ice or reconstructed by deconvolution.

McElwain et al., 2001

Here is a schematic diagram of bubble trapping process for the DE08 ice core:


Figure 1. Schematic diagram of bubble enclosure process at Law Dome, DE08 ice core.

The DE08 core has a resolution at least as fine as 30 years, possibly as fine as 10 years.

Ahn et al., 2012 compared the resolutions of the WAIS Divide, Law Dome DE08 and Dronning Maud Land ice cores over the past 1,000 years and, unsurprisingly, found that the highest resolution core (DE08) had the highest amplitude range and resolved a sharp, short-duration drop in atmospheric CO2 during the nadir of the Little Ice Age (ca. 1610 AD).


Figure 2. From Ahn et al., 2012: “Atmospheric CO2 for the last 1000 years. WAIS Divide data (red, this study) are compared with those from the Law Dome (blue) [Etheridge et al., 1996; MacFarling Meure et al., 2006] and EPICA Dronning Maud Land (black) [Siegenthaler et al., 2005]. To facilitate comparison of CO2 records, a Gaussian filter (1σ = 10 years) was applied to interpolated annual data sets (darker lines). OSU stands for Oregon State University and CMAR, CSIRO Marine and Atmospheric Research.”

 The DE08 ice core’s resolution is so good, that it even detected a pause, possibly even a drop, in atmospheric CO2 during the mid-20th century cooling period.

The stabilization of atmospheric CO2 concentration during the 1940s and 1950s is a notable feature in the ice core record. The new high density measurements confirm this result and show that CO2 concentrations stabilized at 310–312 ppm from ~1940–1955. The CH4 and N2O growth rates also decreased during this period, although the N2O variation is comparable to the measurement uncertainty. Smoothing due to enclosure of air in the ice (about 10 years at DE08) removes high frequency variations from the record, so the true atmospheric variation may have been larger than represented in the ice core air record. Even a decrease in the atmospheric CO2 concentration during the mid-1940s is consistent with the Law Dome record and the air enclosure smoothing, suggesting a large additional sink of ~3.0 PgC yr-1 [Trudinger et al., 2002a]. The d13CO2 record during this time suggests that this additional sink was mostly oceanic and not caused by lower fossil emissions or the terrestrial biosphere [Etheridge et al., 1996; Trudinger et al., 2002a]. The processes that could cause this response are still unknown.

[11] The CO2 stabilization occurred during a shift from persistent El Niño to La Niña conditions [Allan and D’Arrigo, 1999]. This coincided with a warm-cool phase change of the Pacific Decadal Oscillation [Mantua et al., 1997], cooling temperatures [Moberg et al., 2005] and progressively weakening North Atlantic thermohaline circulation [Latif et al., 2004]. The combined effect of these factors on the trace gas budgets is not presently well understood. They may be significant for the atmospheric CO2 concentration if fluxes in areas of carbon uptake, such as the North Pacific Ocean, are enhanced, or if efflux from the tropics is suppressed.

MacFarling Meure et al., 2006

From about 1940 through 1955, approximately 24 billion tons of carbon went straight from the exhaust pipes into the oceans and/or biosphere:


Figure 3. Law Dome DE08 ice core indicates a CO2 “pause” in the mid-20th century.

Ahn et al., 2012 constructed a series of synthetic ice cores of varying resolution to mostly explain the difference between the DE08 and WAIS Divide cores in resolving the LIA CO2 plunge ca. 1610 AD:


Figure 4.  From Ahn et al., 2012: “Smoothing an imaginary atmospheric CO2 time series (green line). The synthetic atmospheric CO2 time series has slightly larger decrease of CO2 than Law Dome records at ∼1600 A.D. To better compare magnitude of CO2 decrease at ∼1600 A.D., we subtracted 3 ppm of CO2 concentration from WAIS Divide core record (blue line) and compared with three synthetic smoothing curves (purple lines).”

There is a fundamental relationship between frequency and amplitude.  If you apply a low pass filter or smoothing average to a time series, you attenuate the amplitude response:


Figure 5. Sin wave with low pass filter and 10-pt smoothing average applied. Note the reduction in amplitude due to filtering and/or smoothing. (Wood for Trees –

Breaking a Perfectly Good Hockey Stick

I downloaded a composite ice core CO2 record (0-800 kyr BP) from Bereiter et al. (2014) and generated the standard CO2 Hockey Stick:

No Smooth

Figure 6. Composite CO2 record (0-800 kyr BP) from Bereiter et al. (2014).

This is a composite of the following ice cores:

-51-1800 yr BP:’ Law Dome (Rubino et al., 2013)
1.8-2 kyr BP: Law Dome (MacFarling Meure et al., 2006)
2-11 kyr BP: Dome C (Monnin et al., 2001 + 2004)
11-22 kyr BP: WAIS (Marcott et al., 2014) minus 4 ppmv (see text)
22-40 kyr BP: Siple Dome (Ahn et al., 2014)
40-60 kyr BP: TALDICE (Bereiter et al., 2012)
60-115 kyr BP: EDML (Bereiter et al., 2012)
105-155 kyr BP: Dome C Sublimation (Schneider et al., 2013)
155-393 kyr BP: Vostok (Petit et al., 1999)
393-611 kyr BP: Dome C (Siegenthaler et al., 2005)
612-800 kyr BP: Dome C (Bereiter et al., 2014)

These ice cores are of vastly different resolutions.  Petit et al., 1999 indicate that the CO2 resolution for Vostok is 1,500 years. Lüthi et al., 2008 suggest a CO2 resolution of about 500 years for Dome C.  It appears that the high resolution Law Dome DE08 core was just spliced on to the lower frequency older ice cores.

If I apply smoothing filters to the DE08 ice core in order to match the resolution of the lower resolution ice cores, I get a considerably different picture.

Using the information in Table 1 from Ahn et al., 2012:

Ice Core Name Mean Temp. (°C) Acc. Rate (cm we/yr) Ice-Gas Age Diff. (yr) Gas Age Distribution (yr) Reference for Gas Age Distribution
Dronning Maud Land –44.6 6.4 835 59 ± 5 Siegenthaler et al. [2005]
DE-08 (Law Dome) –19 110 31 10 Trudinger [2000]
DSS (Law Dome) –22 60 58 14 Trudinger [2000]
WDC05A (WAIS Divide) –31 22 205 ≥30? this study

I plotted the relationship between Ice-Gas Age Difference and Gas Age Distribution and used this to calculate a gas age distribution for the Holocene portion Vostok core:

Gas Age Dist

Figure 7. Δice-gas age vs gas age distribution suggests a gas age distribution of 130 years for the Holocene portion of the Vostok ice core.

The application of a 130-yr smoothing filter to the DE08 core yields a Hockey Stick with a seriously shortened blade:

130 Smooth

Figure 8. A 130-yr smoothing filter makes the industrial era rise in CO2 appear far less anomalous.

If I use a 500-yr smoothing filter, the Hockey Stick loses its blade completely:

500 Smooth

Figure 9. A 500-yr smoothing filter totally removes the Hockey Stick’s blade.

I didn’t even try to use the instrumental record, because it would be a single data point at the same resolution as the Vostok and EPICA Dome C ice cores.


The lower frequency ice cores are not capable of resolving century scale CO2 shifts.  As such, they cannot be used to rule out the possibility of short duration fluctuations comparable to the industrial era rise in atmospheric CO2 during the early Holocene and Pleistocene.  And thus do not contradict the conclusions of Wagner et al., 1999:

In contrast to conventional ice core estimates of 270 to 280 parts per million by volume (ppmv), the stomatal frequency signal suggests that early Holocene carbon dioxide concentrations were well above 300 ppmv.


Most of the Holocene ice core records from Antarctica do not have adequate temporal resolution.


Our results falsify the concept of relatively stabilized Holocene CO2 concentrations of 270 to 280 ppmv until the industrial revolution. SI-based CO2 reconstructions may even suggest that, during the early Holocene, atmospheric CO2 concentrations that were 300 ppmv could have been the rule rather than the exception.

Or Wagner et al., 2004:

The majority of the stomatal frequency-based estimates of CO 2 for the Holocene do not support the widely accepted concept of comparably stable CO2 concentrations throughout the past 11,500 years. To address the critique that these stomatal frequency variations result from local environmental change or methodological insufficiencies, multiple stomatal frequency records were compared for three climatic key periods during the Holocene, namely the Preboreal oscillation, the 8.2 kyr cooling event and the Little Ice Age. The highly comparable fluctuations in the paleo-atmospheric CO2 records, which were obtained from different continents and plant species (deciduous angiosperms as well as conifers) using varying calibration approaches, provide strong evidence for the integrity of leaf-based CO2 quantification.


Ahn, J., E. J. Brook, L. Mitchell, J. Rosen, J. R. McConnell, K. Taylor, D. Etheridge, and M. Rubino (2012), Atmospheric CO2 over the last 1000 years: A high-resolution record from the West Antarctic Ice Sheet (WAIS) Divide ice core, Global Biogeochem. Cycles, 26, GB2027, doi:10.1029/2011GB004247. LINK

Bereiter, Bernhard.  Sarah Eggleston, Jochen Schmitt, Christoph Nehrbass-Ahles, Thomas F. Stocker, Hubertus Fischer, Sepp Kipfstuhl and Jerome Chappellaz. 2015. Revision of the EPICA Dome C CO2 record from 800 to 600 kyr before present. Geophysical Research Letters. . doi: 10.1002/2014GL061957. LINK

Bereiter et al. (2014), Revision of the EPICA Dome C CO2 record from 800 to 600 kyr before present, Geophysical Research Letters, doi: 10.1002/2014GL061957.  Data

Lüthi, D., M. Le Floch, B. Bereiter, T. Blunier, J.-M. Barnola, U. Siegenthaler, D. Raynaud, J. Jouzel, H. Fischer, K. Kawamura, and T. F. Stocker. 2008. High-resolution carbon dioxide concentration record 650,000-800,000 years before present. Nature 453(7193):379-382, doi: 10.1038/nature06949.  LINK

MacFarling Meure, C., D. Etheridge, C. Trudinger, P. Steele, R. Langenfelds, T. van Ommen, A. Smith, and J. Elkins. 2006. The Law Dome CO2, CH4 and N2O Ice Core Records Extended to 2000 years BP. Geophysical Research Letters, Vol. 33, No. 14, L14810 10.1029/2006GL026152. LINK Data

McElwain et al., 2001. Stomatal evidence for a decline in atmospheric CO2 concentration during the Younger Dryas stadial: a comparison with Antarctic ice core records. J. Quaternary Sci., Vol. 17 pp. 21–29. ISSN 0267-8179.  LINK

Petit J.R., Jouzel J., Raynaud D., Barkov N.I.,  Barnola J.M., Basile I., Bender M., Chappellaz J., Davis J., Delaygue G.,  Delmotte M., Kotlyakov V.M., Legrand M., Lipenkov V., Lorius C.,

Pépin L., Ritz C., Saltzman E., Stievenard M., 1999, Climate and Atmospheric History of the Past 420,000 years from the Vostok Ice Core, Antarctica, Nature, 399, pp.429-436. LINK

Petit, J.R., et al., 2001,  Vostok Ice Core Data for 420,000 Years, IGBP PAGES/World Data Center

for Paleoclimatology Data Contribution Series #2001-076.  NOAA/NGDC Paleoclimatology Program, Boulder CO, USA. LINK

Wagner F, et al., 1999. Century-scale shifts in Early Holocene CO2 concentration. Science 284:1971–1973.

Wagner F, Kouwenberg LLR, van Hoof TB, Visscher H, 2004. Reproducibility of Holocene atmospheric CO2 records based on stomatal frequency. Quat Sci Rev 23:1947–1954.  LINK

Further Reading

Fischer, H. A Short Primer on Ice Core Science. Climate and Environmental Physics, Physics Institute, University of Bern.  LINK

Featured Image Source

218 thoughts on “Breaking Hockey Sticks: Antarctic Ice Core Edition

  1. Yeah, it’s doubled from the lowest level in earth’s history. That’s like someone who’s bank account is nearly empty complaining because someone put a bunch of money in it.

  2. This is well presented and matches common sense.
    It talks time for air to be trapped in ice. CO2 will migrate until it’s trapped.

    Even then it may migrate and smooth again if anything disturbs the ice (resonance from wind vibration, tectonic wobbles, any large impact above as the millennia pass, etc.)

    However, figure 7 has a r2 of 0.999. That looks too good to be true.

    • It’s only five data points — and it is an exponential, which means (by definition) three points is an R2 of 1.000

      It’s not really useful to calculate an R2 with five data points.

      • 4 data points. The fifth was calculated from the other 4. Pretty well every permutation I tried yielded a power function as a best fit trend line.

      • The minimum sample for statistical calculations is considered to be 32. Some say 50 is a better standard. In terms of solid quartz rock fluid inclusions, geologists constantly complain about fluid migration in/out of the voids, especially out, saying it contaminates the results. Meanwhile, over in ice acting like a mushy, porous plastic, it is absolute for its gas readout. Ahem, no.

    • Each summer there are drill-down funnels of melt water doing what to your drill core results? Yep, making a mess. Water ponding each summer. Ice flows with plastic state turbulent mixing. Absolute gas results to some. Changes in any salinity of that ice from coastal fog unless dead in the middle of the continent, and the O-18/16 trend changes as well, shifting the perceived temperature. Then creeks and ponds of water come along, and change the salinity. It sounds to me like a mess made in Greenpeace purgatory allowing people wide discretion to say whatever results suit the science of the time.

      • Being a geo, I tend to look at this as a “glass half-full” thing. Despite all of the challenges, these folks do get some decent cores. I wish we could do as well with sidewall cores… LOL!

    • Don’t forget gas diffusion of CO2 from deeper layers (higher pressure) to higher layers (low pressure).
      This means, that deep layers certainly show lower CO2 content than high layers or at least top layers.
      This continues down until the firn layer, that seals CO2 at about 200 ppm.
      Viewed all together, it results in a perfect hockey stick, which shows everything but reality.

      • Reality is buried in there somewhere… Kind of like the pony under a pile of horse schist under a Christmas tree… 😉

  3. Once again they have stitched a short term high resolution data set onto a long term low resolution data set and hey presto….a hockey stick.

    The direct chemical CO2 measurements show that CO2 has been higher than present day readings at least twice in the last 200 years.

  4. It would explain a good deal if this “hockey stick” on CO2 levels in ice is just like Mann’s hockey stick–a measurement artifact.

  5. “The application of a 130-yr smoothing filter to the DE08 core yields a Hockey Stick with a seriously shortened blade”
    But whta is the point? Yes, ice cores from long ago have less resolution. But that doesn’t affect what we know about more recent times. You say that the last 30,000 years have annual resilution.

    It’s possible, from the resolution, that long ago a brief CO2 peak went unobserved. But that makes no physical sense. It took the burning of about 400 Gt C of fossil C to reach our present levels. That is almost as much as was in the air when we started. Where could the carbon have come from in the past to create a comparable peak?

    • Circular argument. Or perhaps magical transfiguration. The carbon and oxygen were always there.

      The level of CO2 and even the temperature is not a problem. It is the rate of change that is feared. It may be so fast that we can’t adapt.
      The claim is that the current rate is unprecedented. That is the debunked claim.

      If CO2 changed naturally as fast as it does now (from the oceans or volcanoes or forest fires or whatever) then…
      We could not know from the ice cores.

      Absence of evidence is not evidence of absence.

    • Nick,

      I’m not disputing “what we know about more recent times.” The point is that every method of estimating pre-industrial CO2 levels, apart from Antarctic ice cores, indicates that the levels were higher and much more variable. Plant stomata and Greenland ice cores both indicate that >300 ppm was not uncommon, possibly the norm. These numbers are generally rejected because they aren’t supported by the Antarctic ice cores. However, most of the Antarctic ice cores lack the resolution to be used this way.

      Where would the carbon have come from? Primarily the oceans.

      If the Antarctic ice cores substantially underestimate the variation in pre-industrial CO2 levels and those same ice cores are used to estimate the temperature-driven CO2 flux, then CO2’s sensitivity to temperature is also substantially underestimated and the natural CO2 flux is larger than is currently assumed.

      • The other thing they do is insist that CO2 has a very long residence time in the atmosphere.

        This recent relentless rise in CO2 shows a remarkably constant relationship with fossil-fuel burning, and can be well accounted for based on the simple premise that about 60 percent of fossil-fuel emissions stay in the air.

        There’s good reason to doubt that premise. This article says the residence time is 40 years rather than the 1000 years that NOAA claims. Given the temporal and spatial variation in CO2 I wouldn’t be surprised if it was even as short as ten years. link

      • Nice, thought-provoking work, Dave. Thanks!

        Cheers — Pete Tillman
        Professional geologist, amateur climatologist

      • David,
        “Where would the carbon have come from? Primarily the oceans.”
        Your plot of CO2 history shows a pretty clear maximum of about 280 ppm, reached during interglacials. That isn’t a coincidence. It represents the maximum that can come out of the ocean at peak temperatures (like the Holocene). That is limited by acid/base issues. There is plenty of dissolved inorganic carbon, but not nearly enough (natural) source of acidity to release it to the air. That’s why it hasn’t happened in the period where we have good resolution, and there is no reason to think it could have happened previously. It takes major effort to take 400 Gtons of reduced carbon, oxidise it, and inject the CO2 into the air. That is what is needed to get CO2 up to 400 ppm. And even our effort won’t last forever. It will revert to the ocean, but will take many centuries.

        That’s the other counter to your notion of unseen 400 ppm spikes. Not only where did the CO2 come from, but where could it have gone. It takes many centuries for that CO2 to dissolve into the sea.

        • Nick,

          It doesn’t have to be a coincidence. CO2 could have risen to the mid-300 ppm in all of those interglacial stages and not been resolved by the ice cores.

          Plant stomata indicate that CO2 levels of 300-360 ppm were not uncommon in the Early Holocene and Eemian. Greenland ice cores yield similar results; although in situ CO2 production is a possibility. The Antarctic ice cores lack the resolution to negate this. I’m not suggesting that >400 ppm spikes occurred. If I remember correctly quercas (oak) stomata don’t respond to CO2 levels above 400 ppm. So, most stomata chronologies top off between 330-360 ppm.

          Pre-industrial estimates of oceanic pH are generally derived from atmospheric CO2 levels.

      • David Middleton March 28, 2017 at 3:15 pm

        Residence time isn’t as important as the “e-folding time.”

        I wouldn’t say that one is more important than the other. They are two ways of looking at the same thing. If we assume linear time-invariant (LTI) systems, with everything else being equal, a system with short residence times will also have short e-folding times.

        The thing is that we aren’t dealing with an LTI system. That’s just what most people implicitly assume because they don’t know any better. Even so, when dealing with non-LTI systems we try to find ways to linearize them, otherwise the math is intractable. For a system that we understand well, the linear approximations are pretty good. For anything concerning the atmosphere I need to be convinced.

        The other thing is that the quantities in the global CO2 budget are stated with a great deal more precision than is warranted. I wouldn’t try to parse anything too closely. 🙂

      • Your plot of CO2 history shows a pretty clear maximum of about 280 ppm, reached during interglacials.

        That isn’t a coincidence. It represents the maximum that can come out of the ocean at peak temperatures.


        Your :: smoothed :: plot of CO2 history shows a :: smoothed :: maximum of about 280 ppm, reached during interglacials. [ That isn’t a coincidence. ]

        It doesn’t represent the maximum that can come out of the ocean at peak temperatures.

      • pdtillman March 28, 2017 at 4:01 pm

        Dr. Tillman.

        You’re a brave man to comment here while associated with ASU.

        Thanks for all your great work!

    • Nick — “Where could the carbon have come from in the past to create a comparable peak?”
      ME–some yet to be discovered source. Asking that question in this context implies that we know all of the possible sources. We have no proof of that.

    • “Where could the carbon have come from in the past to create a comparable peak?”

      I think the question should be where did it go?…and why wasn’t it replaced?

    • Nick-“Where could the carbon have come from in the past”. I assume this is a rhetorical question. I would posit a reply to you as follows: Do you mean in the past as in as per Figure 2 which shows CO2 starting to go nearly vertical in approximately 1850? Where was all that carbon coming from?

      • Nick,

        The smoothing isn’t really a vagery. Resolution is an unforgiving feature of signal processing. The “vageries” of smoothing (lateral and vertical resolution) have been the driving force of a helluva lot of sidetrack wells.

        This is a very material “feature” of signal theory… And one that seems to be frequently ignored in climate science.

      • David,
        I’m actually not sure now what “nearly vertical” is referring to. I was looking at the uptick in the blue which is actually about 1800. Resolution is an issue there, because it is a gaussian smooth with a 10yr σ. but maybe John just meant the take-off of the curve around 1850 (which is the date he gave). That is actually due to land clearing in the New World. I’ve set that out in detail here.

      • Nick’s point about what else could have made a comparable change is the past is a discussion worth having but is beside the point of this article, which is to question the validity of claims made on the basis of low resolution ice cores to PROVE that the current peak is “unprecedented”.

        Now if NIck wants to say there are other reasons why higher historic levels are not possible that is another discussion but does not counter the FALSE conclusions made on the basis of low resolution ice cores.

        This is the basic flawed argument of Markum Shake ‘n’ Mix paper which attempted to resurrect Mann’s broken hockey stick.

      • Greg,
        “This is the basic flawed argument of Markum Shake “
        No. The period of poor resolution was much earlier. As DM says, there are 30000 years of annual resolution. And the fact that no spikes independent of temperature changes showed up in that time is already evidence that it doesn’t happen.

        My argument is not beside the point. It says that you aren’t just following a time series that could go anywhere any time. It is a series where fluctuations involve vast movements of material. That in itself limits the frequency rsponse. But it also means that if you want to postulate fluctuations, you need to look for possible causes.

      • Nick,

        The temperatures are resolved annually, not the atmospheric gases. The gases may be sampled annually, but each layer is roughly a 60-yr average due to the gas age distribution.

    • Where could the carbon have come from in the past to create a comparable peak?
      When asked where the money would come from to build his temple, the Reverend Moon replied, “From wherever it is now”. (true story).

      Why assume that since you can’t find the CO2, that Mother Nature won’t be able to find it either?

      • Yes, the “what else could it be” kind of argument is not scientific. We are talking about geological timescales of which we know very little. A massive meteor strike that allegedly wiped out 95% of life on Earth is still only a hypothesis. Last week it was suggested that this made “twice as hot” contradicting the usual suggestion that it created a profound cooling event.

        Short spikes or troughs will not be in the record.

        When we know so little about the distant past “what else could it be” just does not work.

    • Submarine volcanism comes to mind as a possibility.

      How often does the Earth need to “burp”? No one knows. Does it even happen? I don’t know, but I can’t see what would rule it out, given volcanic CO2 seepage.

  6. not to get off topic, but supposedly the signature of anthropogenic CO2 is the lower(?) C14. Is there another explanation for this? I recall hearing that atmospheric C14 does vary over time. Did the strong solar activity of the 30-year period 1970-2000 reduce cosmic ray responsible?
    Also, our modern atmospheric CO2 concentration is measured in Hawaii, is there CO2 measurements for Greenland or Antarctic?

  7. It is well known that ice core CO2 levels are the equivalent of applying a low band-pass filter. However it is extremely likely that current CO2 levels are well above anything seen in hundreds of thousands of years. Levels of 300 ppm during the Holocene Climatic Optimum, as supported by stomata, would not change that.

    • Correct. But it would mean that the anthropogenic contribution to the modern rise in CO2 could be about half of what is generally assumed. 400 ppm is less anomalous if the norm is 300-360 ppm, rather than 280-300 ppm.

      • This would, however, mean that the overall climate impact and thus also the sensitivity of CO2 is too high (In the previous raw theory of the atmospheric effect of CO).

      • And there are several other observational lines of evidence suggesting this must be true. Essay Sensitive Uncertainty in ebook Blowing Smoke. Lweis and Curry 2014.

      • David…one thing really sticks out in your graphs
        CO2 levels above 250ppm are very hard for this planet to maintain…
        ..and that’s f’in scary

      • @ Steven Mosher- Prove otherwise! David is, as he says, being upfront about his speculation. The fact that some “consensus” of other scientists supports a contrary speculation doesn’t mean that they are correct. It only means that a group believes in something speculative. Like Global Warming or a longer residence time for CO2. Or Socialist paradise. Or the tooth fairy. Don’t try to make one form of speculation superior to another. Or do you admit that AGW is founded on speculation?

      • Don’t forget; the CO2 heat is hiding in the oceans. Millions of Hiroshimas worth. Just biding its’ time. CO2 heat is magical that way.

      • Aphan,

        The first thing is to distinguish between evidence and hypothesis. That current CO2 levels are abnormal (at least for the Late Pleistocene) is evidence. The climatic effect of the extra CO2 is hypothesis.

        Personally I think there is evidence for some climatic effect of that extra CO2, but not enough to sustain a catastrophic view at this point.

        Formally one cannot reject the hypothesis that the planet should be cooling but extra GHGs are preventing it from happening. This is the Ruddiman hypothesis. There are important arguments against it, and I don’t believe it is true, but at this point it cannot be rejected.

        However to answer your question, I think it can be supported in evidence that temperatures are not “well above anything seen in hundreds of thousands of years” because the main temperature control in the planet is the level of insolation received at high latitudes, also known as Milankovitch theory of orbital control of glaciations. The change in 140 ppm CO2 equivalent experienced could only be a secondary order factor at most.

        • I mostly agree. However, the degree to which the current CO2 levels are anomalous, relative to the Late Pleistocene and Early-Mid Holocene is speculative.

      • Javier
        “one cannot reject the hypothesis that the planet should be cooling but extra GHGs are preventing it from happening.”

        Not only preventing it from cooling. The possibilty is still well and truly on the table.

      • That current CO2 levels are abnormal (at least for the Late Pleistocene) is evidence.
        to make that claim accurate you would need to use the same test to measure both. Otherwise what may be abnormal is the difference between the tests applied to each time period.

        • Well… The fact that we are taking carbon out of geologic sequestration and returning it to the carbon cycle… kind of dictates that the current CO2 levels have to be at least somewhat anomalous.

          My point is that the degree to which the modern CO2 levels are anomalous has been exagerrated to the maximum extent possible.

      • At that scale, Antarctic temperatures, that went from -80 to -60 as CO2 rose from 200 to 300, should be above -40 now and the world should be significantly warmer

    • Steven Mosher on March 28, 2017 at 4:12 pm

      Could be….
      Now who is speculative? ??

      ! Steven, makes one smile. Slight return.

      • Yes, I spotted that blunder too. One of the dangers of talking with authority about something you do not know.

        Don’t be too hard on Javier, IIRC he is a reformed “Earth Scientist”.

      • And I’m also a foreigner with English not being my first language, which is rather obvious. Some of my mistakes are on that account. But I take criticism rather well and always take the opportunity to learn from my mistakes, so thanks for the correction.

        • Javier,

          Your English is better than many, if not most, people whose primary language is English.

  8. Fascinating. I have always wondered what is the claimed temporal resolution of the temperature data in all these ice cores. Can I presume that resolution can only be similar to that for CO2? Or is it claimed that they have (eg, for the last 30k years?) solid annual data?

    • The temperatures are better resolved because the d18O is a property of the ice. If the ice layers are annually resolved, the temperatures are annually resolved. The d18O doesn’t mix like the atmospheric gases do.

      • dO18 rains out, however.

        Ice dO18 can change if monsoon patterns change, without any accompanying change in air temperature. The dO18 temperatures are not calculated from the physics of isotope partitioning. They’re developed from statistical matching criteria. Modern dO18 temperature reconstructions are not temperatures in any physical sense.

        Apart from that, regarding ice cores David, your Figure 1 gives a good indication of the ice pressure. When cores are drawn up, that pressure is lost. How much CO2 is lost through pressure fracturing, especially micro-fractures?

        CO2 under pressure in an ice bubble is in equilibrium with CO2 dissolved in the interstitial water-ice. How much of that interstitial CO2 is lost when the core is drawn up?

        Applying analytical thinking to that field, it seems more likely that ice-core CO2 is a lower limit of atmospheric concentrations, not a direct measure.

        Has anyone done a lab study, compressing snow under a CO2 atmosphere, to see how much CO2 is retained in ice-bubbles, how the bubble/ice partitioning works, and how much CO2 is lost when the pressure is suddenly removed?

        Considering the poverty of base-line analytical calibration work in the rest of consensus climatology, I’d venture that little has been done for CO2 in ice-cores, as well.

      • Exactly, Pat. Now, how much thinking about ice at the pressures near the bottom may have different properties compared to the top, as in a phase diagram. Has this question been asked: “Is it possible that supercritical water exists here?”, and if so, the follow up question: “What effect would that have on solubilities and partitioning?”. See:

  9. One thing I’ve always wondered about, is that given how much glaciers can flow, is there really an undisturbed section of 800,000 year old ice in the Antarctic? And how would you know?

    • They can tell when the ice is deformed. The ice cores are generally cited on domes and other features which should have relatively undeformed sections.

  10. “This begs the question”

    A minor point but it does no such thing. It raises the question. Begging the question is a fallacy.

      • Although in the Climate Scientific Conmmunity, insofar as debate goes, it might be more appropriately written
        “That Razes the question”

    • Sadly, lots of people are using ‘beg the question’ to mean ‘raises the question’. I’m afraid we’ve lost that one.

      My favorite misuse is the word fulsome. Its previous accepted meaning was ‘insincere’ as in ‘fulsome praise’. It now means abundant. I love it when politicians use that word. They are accidentally telling the truth.

      Having said the above, I will probably run afoul of Skitt’s Law. I wait with bated breath.

      • If I wasn’t already happily married, I’d ask you what it is you bate your breath with. 😎

      • Murphry’s Law is better because it invariably causes people to say, “Don’t you mean Murphy’s Law?”, which then becomes self-referential. Or ironic or something.

      • Actually, fulsome originally meant abundant, and then moved to profuse, then excessive (implying insincerity) and now finally back to abundant.

    • Ten on March 28, 2017 at 2:50 pm

      “This begs the question”

      A minor point but it does no such thing. It raises the question. Begging the question is a fallacy.

      what fallacy –

      This begs the question – read: – That requires the question.

  11. It’s not Mike’s Nature Trick. Instrumental data weren’t spliced onto the tail end of a reconstruction. But, the spectral mismatch creates a similar effect.

  12. DM, nice post. The same not so tricky time resolution error that Marcott made in his Science paper and then admitted. Of course, Marcott also committed academic misconduct, provable by comparing his thesis to his paper in essay A High Stick Foul in ebook Blowing Smoke. That evidence was submitted in writing to McNutt, then Science editor in chief, with a retraction request. Receipt acknowledged. Nothing done. Another proof of the intellectual bankruptcy of warmunist ‘climate science’.

    • It does no such thing.

      The failure to retract is no more indicative that the request was not credible than it is indicative of a thoroughly broken peer review system.

    • Or the peer review process is so thoroughly broken, that it requires an overwhelming amount of evidence to force a retraction of a paper which should not have passed peer review.

      Marcott is a prime example.

    • “Failure to retract proves only proves that the request to retract was not …” acted upon.

      Benefit of the doubt would allow that the request was deemed “not credible” by someone, but even that is a far stretch from actual proof. (although, If I don’t respond to a reply, consider that proof that the reply is not credible).

      • DonM, judge that from my Curry guest post. Conviction on academic misconduct was warranted. I still view that incident as the final part of my own conversion to rabid skepticism. The first was a deliberate lie by NRDC to Congress inadvertently discovered in 2011 while researching a very different book. My very first post here and at CE– from which I naively learned lots about blogs. But a great general reaction at both. You can dig it out at both. Is also featured differently in my first two published ebooks.

      • Oh… An ellipsys has only 3 dots … More dots is just moronic and not indicative of anything clever.

      • .

        David, your link to Cato is funny. Can you spell K-O-C-H???? First mention is about stolen emails. Please try something a bit less biased, and a bit more reputable, something based on data that isn’t stolen and agenda driven.

        The whole problem is that the PR literature system has been totally corrupted. That is what the Climategate emails revealed to the world. You say you won’t accept that fact because it is “stolen” ( something which has never been established by the competent authorities in the UK).

        That sadly remains the case since little has been done to correct or punish those responsible.

        The level of gatekeeper activities mean that trying to get a paper published that does not fit AGW orthodoxy is massive up hill battle, like trying to correct some of the BS that is on Wonkypedia.

        Go and fix the corruption and blatant , political activism polluting your famous “peer review” system and then you challenge to publish may make more sense.

        Until that happens circumventing the gatekeepers by publishing in other media like WUWT and Climte Etc is what will happen.

      • Where is science “done”?

        Wherever a scientist puts his mind and capacity to work in a scientific discovery quest.
        Gregor Mendel did it at an Abbey.

        Who is a scientist?
        A person that engages in a scientific discovery quest using the scientific method.

        Is peer-reviewing system a requirement for doing science?
        Obviously not. Science was done for centuries before peer-reviewing was instituted by journals, and a lot of science is published in books that don’t undergo peer review. Internet also allows for the dissemination of scientific results and ideas without peer-review, which has both advantages and disadvantages.

        As a curiosity, Gregor Mendel laws, the basis for the entire genetics field, were published in a journal from a local natural history society, which did not have peer review, and he cooked the results to make them look better. Science has strange ways.

        • If Hutton & Lyell had to wait for peer review to accept their science, modern geology would have never gotten off the drawing board.

          Hutton was a physician and Lyell was a lawyer… Geology just happened to be one of their hobbies.

      • >>
        David Middleton
        March 28, 2017 at 7:40 pm

        Oh… An ellipsys has only 3 dots … More dots is just moronic and not indicative of anything clever.

        I would suggest you refer to something like “The Chicago Manual of Style” before you make such a statement. Try sections 13.48 to 13.56 in the sixteenth edition. Section 13.51 discusses “Ellipses with periods” (four spaced dots), and section 13.55 discusses “Ellipsis points in poetry and verse drama” (a line of spaced dots).


    • Marcott’s error is public record…

      20th century portion of our paleotemperature stack is not statistically robust, cannot be considered representative of global temperature changes, and therefore is not the basis of any of our conclusions.

      100% retractable bullschist…

      Current global temperatures of the past decade have not yet exceeded peak interglacial values but are warmer than during ~75% of the Holocene temperature history.

    • You attacked the source of the argument, rather than the argument. This is the definition of the argumentum ad hominem fallacy.

    • Marcott et al., from Real Climate…

      Our global paleotemperature reconstruction includes a so-called “uptick” in temperatures during the 20th-century. However, in the paper we make the point that this particular feature is of shorter duration than the inherent smoothing in our statistical averaging procedure, and that it is based on only a few available paleo-reconstructions of the type we used. Thus, the 20th century portion of our paleotemperature stack is not statistically robust, cannot be considered representative of global temperature changes, and therefore is not the basis of any of our conclusions. Our primary conclusions are based on a comparison of the longer term paleotemperature changes from our reconstruction with the well-documented temperature changes that have occurred over the last century, as documented by the instrumental record. Although not part of our study, high-resolution paleoclimate data from the past ~130 years have been compiled from various geological archives, and confirm the general features of warming trend over this time interval (Anderson, D.M. et al., 2013, Geophysical Research Letters, v. 40, p. 189-193;

    • I just did… by linking to Marcott et al’s Q&A at the Mannian blog, Real Climate. Is English not your primary language? Or is basic logic alien to you?

    • No. It is not that I am “moving the goal posts.”

      The only possibilities are 1) you lack basic 3rd grade reading skills, 2) you are challenged in your grasp of the English language, and/or 3) you are terminally afflicted with serial logical fallacy syndrome.

    • Enargia, got a simple test question for your ‘obvious’ scientific self evident brilliance.
      How many US patents do you have issued at least partly in your own name?
      Now, guess how many I already have issued.
      Now, if you know anything, you now know how to look upthread to answers on Do try.
      My guess is 13:0. Which does say something about you scientifically. But not particularly pleasant.

    • I am a scientist and do science every day. I only asked the question because you seemed to think that science was actually done in magazines like Nature and Science.

      Now, if you are not a moron, please explain in your own words, how and whet science is “done.”

    • I suggest you learn the definition of argumentum ad hominem fallacy. It will help you avoid appearing as a total fracking moron in Internet discussions.

      The caveat being your native language. Your appatent manifest ignornce still leads me to believe that English might not be your primary language. In which case, your mind-numbingly ignorant posts are entirely understandable.

  13. Stigmata give much better eestimates of paleo CO2 levels. It should be remembered that CO2 Diffuses in ice up until pressures force it into calthrate put simply it doesnt stay in place it smears out. It even smears out when the firn forms. So it isnt even initially trapped as you would expect. Add to that dodgy chronologies and paleo ice records not much more thsn an intetesting talking point and enough ice cubes to make a whole load of gin and tonics

    • Also one thing that troubles me is that the cores are raised from great depths, where they were under great pressure, to a surface where the pressure is far less. Seems to me the cores must fizz like a soft drink, when the pressure so abruptly becomes less. I wonder how they handle that.

      • Caleb, according to ferdinand (who’s pretty darn good with this ice core stuff), the bubbles are checked with electron microscopes for cracks after the cores have relaxed. That way they can be sure the air in the bubbles is intact. i’m not sure if i’ve answered your concern here. Before long, ferdinand will most certainly show up and he can address you (and correct me) in further detail…

      • afonzarerlli, I was going to ask that same question about the pressure changes and you answered it partially, if the bubbles aren’t cracked how do they measure the content? With light beams and spectra? ( I am a learner so if you can direct me where to look I’d appreciate it) The reason I ask, if the bubble is under pressure “X” at say 10,000 ft below the ice surface, what would the content look like at sea level pressures? Is there an mathematical explanation for that and could those molecules change as they go from being under high pressures to way lower pressures? Thanks.

      • “Caleb, according to ferdinand (who’s pretty darn good with this ice core stuff), the bubbles are checked with electron microscopes for cracks after the cores have relaxed. ”

        Calling BS on that one : every bubble is checked for quality? You have to be joking. I don’t recall Ferdi saying that but an original citation is required.

      • I hadn’t even considered bacteria. (Smack skull.)

        I’ve seen some studies that describe how the very first micro-critters that colonize glacial soils discover the soil is basically devoid of nourishment, due to the scouring power of glaciers, and therefore they have to grab methane from the air. This utterly messed up the calculations aimed at showing that a warming arctic would release lots of methane, because the bratty micro-critters were eating all the evidence.

        It would be just like those little brats to sneak inside ice-core air-bubbles, and mess with that data as well.

        Micro-critters have no respect for our higher IQ’s.

        This old post might amuse you:

    • BB, And when the core drill relieves the local pressure, the clathrate cage
      shatters and the gas is freed and whatever concentrations might have been
      measured are distorted.

    • But isn’t their a limit to the number of Stomata that can be produced regardless of the higher or lower level of CO2?
      If Stomata production drops off at a specific level of CO2, then leaves will not indicate a higher level even if it does exist.

      • If I remember correctly most Quercus (oak) species don’t exhibit a stomatal response above about 400 ppm.

  14. All this work on CO2 is a sideshow in relation to temperatures….i can’t wait for the carbon train to run out of steam/coal/??? aghh… Just use Diesel. The mechanisms that change pressure is where the real climate action should be. Ie the consequential convection and conduction effects through the hemispheres (mainly southern because no land mass influences) and specifically in relation to the stratosphere, mesosphere, ozone and cosmic ray changes on polar vortex behaviour.

  15. Figure 6 and the supporting narrative from the ice core industry are naive nonsense. The only reason that the ice core record of CO2 even matches the record of atmospheric CO2, what was actually measured in the atmosphere, is that the ice core record was FUDGED. See Jaworowski (1992, 1997). The truth is that, before the 20th century, we don’t know what CO2 in the atmosphere was.

      • David, just finished my comment about Jaworowski and read yours. How wrong was he and was it due to poor technique or other matters…ed

        • If I remember correctly, according to Lawrence Soloman’s “The Deniers,” Jawaworski asserted thar ice-air age delta was arbitrary and unjustified. His argument was that the ice cores showed higher pre-industrial CO2 and that the ice-air age delta was arbitrarily applied to bring the higher CO2 levels forward in time. His argument sounded reasonable to me, until I took the time to study the ice core data and methods.

      • Thanks David, I’ll read do some more reading re. ice cores and methods. Is there an inherent Heisenberg’s uncertainty principle that applies to ice core data recovery. They do seem to be large, frozen and slippery!

  16. So we have high resolution vs low resolution and some shape shifting. A number of years ago the late Prof. Zbigniew Jaworowski questioned the mechanical validity of ice cores stating that many gases that were trapped were altered by the extreme pressures, cutting fluids and even liquid water that was present in the samples. He arraned many expeditions and was part of teams that drilled many cores.

    He states that the handling of the cores, sizes and methods of extracting the gases were varied and the temperatures they were held had varied and amazingly some had shrunk!

    ” Important information on the temperature changes during collection of the cores, their transportation from Greenland, Antarctica, or storage facilities in the United States, to laboratories in Europe or Australia, and during their long storage, are not given at all. That such temperature changes occur may be inferred from Pearman et al (1986) who found that parts of the Law Dome core exhibited “post-coring melting”. The Law Dome samples exposed to melting yielded significantly lower CO2 concentrations in air extracted by the “dry” method from the air bubbles. This indicates that a proportion of the CO2 from air bubbles was dissolved in meltwater, and by subsequent refreezing (at -80ºC) of this water, was eliminated from the bubbles.

    According to Etheridge et al (1988) the Siple core drilled during the Antarctic summer of 1983/84 and used by Neftel et al (1985) was exposed to melting, but the latter authors did not mention this in their paper. Other cores from Siple also “melted partially during shipment” (Alley and Bentley 1988). Increasing the temperature of polar ice cores during transportation and handling to near the melting point is probably not a rare phenomenon and was often reported (eg Ng and Patterson 1981; Boutron and Patterson 1983; Legrand et al 1988), but not by CO2 students except Etheridge et al (1988)”

    A more general article here written for the U.S. Senate Committee

    Now, I haven’t read much about Jaworowski here at WUWT so don’t know if these issues have been discussed in the past but reading articles from someone who was on some expeditions I think would have some weight. Jaworowski was also a radiation expert and wrote extensively about Chernobyl.

    • There are a lot of challenges to drilling, preserving and analyzing ice cores. I haven’t seen anything that suggests that the ice core people have intentionally misled the public on these challenges.

      However, I do think there is a pattern, particularly in secondary publications, of ignoring the limitations of resolution in these ice cores. Most of the primary authors are very up front about these limitations. I have cited numerous examples in this post.

      My criticisms aren’t so much directed at the primary ice core science as they are at secondary applications of the ice core results.

  17. You know who coined the term treemometer?

    Wrt to indirect measurements…how much does the earth weigh?

    • I’m actually a fan of dendroclimatology. I’ll take an Esper treemometer over a Mannian thermometer any day of the week.

    • No “treemometer” has any basis in physics. Like who you like, David, but all that work is equally crockericious.

      Treemometers are not “indirect measurements” of temperature. Nice work confounding the language, though. The physical relation of tree ring width or density to temperature is entirely unknown.

      • “Treemometer” is slang. When properly calibrated and controlled for other variables, tree ring chronologies are useful temperature proxies. The key is in calibration and controlling for other environmental variables, like CO2 fertilization.

    • The Earth doesnt weigh anything. But we can calculate its mass. Was that your point?

      DM, very interesting post, thanks. I repeat a comment ive said before. If I wanted to store a gas standard of CO2 at fixed concentration for several thousand years, i would not use an ice block contsinment vessel. And where have potential impacts of bacteria and decaying organic matter been considered? Antarctica has relatively clean air but it is hardly devoid of life, nor vulcanism.

    • dixon March 28, 2017 at 8:03 pm
      The Earth doesnt weigh anything.
      This is a matter of definition. And fodder for little fun.

      If weight is defined as the force a mass at rest with respect to the local gravitational field applies to whatever supports it from falling into that field, the Earth weighs a lot. The crust presses upon the mantle with its weight, plus that of the oceans and the atmosphere. The mantle presses upon the core with its weight, plus that of the crust, plus that of the oceans and the atmosphere. The outer core presses on the inner core with its weight plus… All of this weight actually exists, we just have no way to empirically measure it. While this weight produces what we call pressure, pressure is not the same as weight. Weight is unidirectional, pressure is omnidirectional. Of course, the increment of force each atom adds to the total exerted on matter beneath it decreases with depth. Whether the central atom has any weight might be debated, but it is certain that all other individual parts of the Earth have weight.

      If you meant the Earth as a whole relative to the gravitational field the Earth is in (the Sun’s), then since the Earth is not at rest in that field, the Earth as a whole indeed weighs nothing.

      On the other hand, if your “weigh” is a verb, the Earth weighs everything that is placed upon a scale, as the Earth provides the gravitational force that is essential for something to be weighed.


    • The key is in calibration and controlling for other environmental variables, like CO2 fertilization.

      … and most importantly humidity !

      We do not know humidity records even as well as we know temperature records, so the idea that you can “calibrate” a multivariate proxy to extract one variable is foolish falsehood.

    • SR – very good, I enjoyed that. But the weights you talk of are not something that is the (whole) Earth, so I stand by my remark – which was indeed making reference to the fact that weight is a function of gravity acting on mass. In fact the more I think about it, the more the ‘weight of the Earth’ is a metric like the ‘global temperature of the Earth’: a meaningless nonsense dreamed up for the purpose of obfuscation or lazy shorthand, both inexcusable for scientists. Still, mustn’t derail this thread anymore. Dixon out.

  18. Conclusion

    The lower frequency ice cores are not capable of resolving century scale CO2 shifts. As such, they cannot be used to rule out the possibility of short duration fluctuations comparable to the industrial era rise in atmospheric CO2 during the early Holocene and Pleistocene.

    Great! Thanks – Hans

  19. Has anyone looked in depth into whether or not the CO2 in the bubbles reacts with the ice?

  20. The warmunists are wrong about so many aspects of climate change, or making wild guesses, that I have a hard time believing air bubbles in ice cores give us accurate historical CO2 levels going back hundreds of thousands of years.

    Interesting that the warmunists cling to the CO2 levels in the ice cores as solid “facts” … but totally ignore the most important lesson from ice cores — CO2 peaks lag temperature peaks by 500 to 1,000 years!

  21. It should be noted that the Greenland ice cores also measured CO2 levels back to 72,000 years ago or so and they were so variable and were much much higher than expected based on the Antarctic ice cores.

    There was so much discrepancy that they just threw the Greenland ice core data out and said ignore this.

    GISP2 CO2 from about 10,000 to 72,000 years ago.

    Match up ice-core depth with estimated age here.

    For example, GISP2 has CO2 at 325 ppm at 10,700 years ago and 285 ppm at 45,000 years ago.

    • Bill,

      Funny thing… They often seem to be OK with the Greenland ice core CH4 numbers. Funny… In a Roswell/Area 51/Fox Mulder kind of way… 😉

    • This is the underlying problem of only accepting what you “expect” as being a valid result. If there was a point in an ice dataset which show a similar spike to current levels it would almost certainly be rejected and removed by data QA processing.

      There is an overwhelming desire in climatology for all data to tell the same story. There are international conferences on “data homogenisation”. It is all part of creating and maintaining an unwarranted degree of certainty in the data and conclusions.

    • There was so much discrepancy that they just threw the Greenland ice core data out


      Greenland CO2 was the original Oeschger’s work that got him on board D/O events. The problem is that CO2 is a well mixed gas, specially at multiyear resolutions, and Greenland CO2 levels did not match Antarctic CO2 levels, and that was simply impossible. So an investigation was launched, and it was determined that Greenland CO2 levels were the result of chemical contamination from some salts present in the ice. As Antarctica is huge, isolated, and circled by SAM, the ice has almost no salt contaminants and so CO2 levels are more correct. That is the reason Greenland CO2 levels are no good. I was also suspicious when I first heard but the issue appears bona fide.

      As every cloud has a silver lining, Paul Mayewski has made a career out of studying climate change in the salt contaminants of Greenland ice cores.

      • The potential in situ CO2 production and other environmental issues make the use of Greenland ice cores more challenging. However, the accumulation rates make it a much higher resolution tool than most, if not all, Antarctic ice cores.

  22. As far as the hockey stick thing is concerned I find it suspicious but then again, I looked at the calendar and it is the run to the Stanley Cup :). ( And of course it is also “March Madness”). And hey NBA is ready for a slam dunk and the MLB is in “Spring Training”. Have fun everyone.

  23. Thank you David,
    It has been said many times over the years that one cannot draw short term inferences from poor resolution ice core data. This is intuitively, common sensical, qualiatively so.
    Your work here is a valuable, even strikingly visual, quantitative support for this. Researchers who blithely press ahead with invalid comparisons should have this data burned into their brains.
    It is shameful that poor quality science has been produced by the activists responsible. They should at least have expressed formal confidence limits on their data. Misuse, or no use, of formal error estimation is rampant in climate work. If it was routinely used correctly, many of these hockey stick type wrong statements would have been headed off at the pass.

  24. “In the WAIS Divide ice core, each of the past 30,000 years of snowfall can be identified in individual layers of ice”

    I had not realized that Antarctica is the most amazing Continent there is!

    A continent that never experiences severe or multi-year droughts,
    • Never experiences heavy rain or flooding,
    • Always has summer melt,
    • Never suffers from excessive summer melt,
    • Where ice melt does not drain down, filling voids then freezing,
    • Where frozen melt or rain does not form excluded gas bubbles,
    • Where the ice always settles and sits in one spot,
    • Where laminar ice flow does not occur,
    • Where compression does not cause ice to thin via sideways flow,
    • Where the ice is never stripped of snow by wind,
    • Where drifts never form,
    • Where avalanches and snow slumps never occur,
    • Where subsurface terrain never causes ice flows to merge.

    Apparently, Antarctica is a land where norm thrives under perpetual daily, seasonal, annual, decade conditions.

    Imagine that?
    Pages 18 & 25

    • • Always has summer melt,
      • Never suffers from excessive summer melt,

      Please post max “summer temps” for Antarctica !

      • • Where avalanches and snow slumps never occur,

        Law Dome , Gomez Dome, Dome C …. see any kind of picture forming? Ice cores are usually taken from the local highpoint in the terrain where snow and ice can accumulate but don’t be covered by slumps and avalanches and are not disturbed by sideways creep.

        Ease up on the heavy sarcasm and do a little reading.

      • The high point is what people think/believe is the highpoint.

        While it is possible, it is not viable to believe the high point, an ice high point no less, has been the highest point forever.

        Nor can “max” high temps be posted for all Antarctic history. Claims for ionized atoms/molecules measurements under the Southern ozone hole also concern me.

        A high point is where sideways creep is greatest.

        Yes, the presentation is well done, and very interesting.
        What was that about reading?

        In any real world industrial/commercial/architecture/flight/oceanic/etc design, the design tem utilizes test engineers to identify and list every possible concern/effect/external and internal influence/physics/weather/storm/geological impacts.

        For major financial programs there is a similar effort to identify every possible datum/input/mistype/calculation/bit size/data transfer/data storage/data retrieval/etc.

        Both systems require honest attempts predetermine every possible fault, before development. As design/development proceeds, more concerns will be added to the test process.
        Running a classic input test deck is just one flavor of one concerns.

        Without constructing a proper test design and process, assumptions, single focus desires, simple process and output expectations, whatever, going into a study skews every output according to researcher perception and expectation.

  25. Point #1: Don’t you have to prove CO2 can even cause climate change? Historical records seem to prove CO2 hasn’t been a cause of any of the pre-industrial climate changes. Why the focus on CO2 anyway? We haven’t had extreme climate variations during the industrial age.
    Climate Changed Caused the Pre-Industrial Bronze Age Collapse

    Point #2: Why the lack of focus on stomatal frequency? That seem a more reasonable method than CO2.
    Reproducibility of Holocene atmospheric CO2 records based on stomatal frequency analysis

  26. Using the information in Table 1 from Ahn et al., 2012:

    Acc. Rate (cm we/yr)

    Dronning Maud Land 6.4
    DE-08 (Law Dome) 110
    DSS (Law Dome) 60
    WDC05A (WAIS Divide) 22

    Given that most of the speculations I’ve seen suggest that over the last million years there has been virtually no opportunity for any significant melting of the Antarctic ice sheets at all, even these feeble rates of annual accumulation would have resulted in an ice sheet from 35 miles to 500+ miles thick if the ice wasn’t disappearing by some other means. My preferred alternate would be that as the ice reaches a critical height a compressive limit is passed and the ice is extruded out to the ocean. The trouble with this speculation is that it makes it a hard case to support the notion that the ice is able to maintain a precise vertical record while hundreds of miles of ice is moving in, down, and out of the ice sheet.

  27. Technical comment:

    The NASA webpage quoted above is here

    It clearly states 60 % of emissions stay in the atmosphere. However, I believe this figure should be between 40 and 50 %, and most likely it’s closer to 40 %, say 43-44%. Would somebody comment on this specific point. I have this figure coded in the spreadsheet I use to estimate CO2 concentration as a function of different burn rates for oil, heavy oil, gas, natural gas liquids, and coal. This is what I use to estimate a peak co2 concentration around 630 ppm, and I need to make sure the fraction that stays over time isn’t 60 % as stated by the NASA webpage. Thanks.

  28. Wetlands are not a carbon sink.

    A good way of looking at this is rice paddies. The IPCC’s carbon balance lists
    rice paddies as a man caused CH4 source.

    Before the paddies are flooded, the upwelling natural gas and the locally
    generated CH4 are in balance with the microbes which oxidize it, and CO2
    could be measured. When the farmer floods the paddies, the water forces
    the hydrocarbons to rise faster than the microbes can consume them, so the
    carbon is measured as a CH4.

    There is no change, ultimately, in the carbon in the atmosphere.

    In the wetlands, when wet, the gas rises as a hydrocarbon. When the water
    is drained, the aerobic microbes bloom to the amount of food available,
    oxidize the hydrocarbons, and CO2 rises.

    CO2 readings at the ground level are a highly local event. This is the reason
    for widely varying stomata readings from different locations the same year. The
    total ambient atmospheric carbon, CO2 plus hydrocarbons, before human
    contribution excluding volcanoes, oceans, etc, depend upon the amount
    of the earth not frozen.

    The richness of the soil is a visual guide. The richer the soil, the more
    hydrocarbons upwelling through it, the more the local culture can eat,
    oxidize, and the CO2 reading at the surface will be higher.

    A simple way to test this requires a CO2 meter and a 12″ stainless
    steel salad bowl and a 10 lb weight.

    I recently did this test on my property. On a day with less than 3 mph
    wind, I measured the CO2 reading at 6′. 404 ppm. I placed the meter on
    the ground, covered it with the inverted ss bowl, placed the 10 lb weight
    on it, and left it there for 12 hours. The reading at the end of the 12 hr
    period was 1394 ppm.

    The carbon from this area will be about the same as long as it is not
    covered in ice, short of a tectonic shift.

    The plants were never in danger of dying for lack of food.

    • Peat bogs are famous for trapping carbon for 10’s of thousands of years.

      That’s fascinating. You stop photosynthesis, and then you notice that no CO2 has been taken up.

    • Jerry it also depends on when you take the readings. On a field of corn the bacteria and other organic sources build up the [CO2] later in the day and through the night but when morning there is a feeding frenzy as the plants gobble it up reducing concentration by half.

      This is why on the course I look after the importance of morning sun for good growth can’t be overstated….ed

      • Polski,
        The reason for the stainless steel bowl is to isolate the location from ambient
        influences. Take the reading for 24hrs. Just do other soil tests the same way
        so that the comparison is valid.

        Measure the ground temperature with a probe and check the same spot when
        it is warmer and colder and even when the ground is frozen. Test when the
        ground is very wet and when the ground is very dry.

    • Interesting card. It also shows that the greatest profit of the greening are average widths, not the arctic regions. Apart from eastern Siberia, there are also marked declines in leaf areas. Profiteers are southern and eastern Europe (quite contrary to the horror of the IPCC) and India. In this case, the sharp drop in the leaf surface in the inner Himalayas is noticeable, whereas the surface of the leaf clearly increases on the slope of the Hialaya and the lower continent.

  29. This change of variability as a function of change of scale of measurement has a name in geostatistics – the support of the measurement. Variance is always preserved under smoothing, so if you have measures of variance at different scales and know the resolution of the sample (ie its effective volume on which the measure was made) then you can estimate the variance at other scales.

    This observation was part of the empirical MSc thesis submitted by none other than Danie Krige (of Kriging fame), back in 1951.

    There is an excellent discussion of the topic and its solution/calculation in the book “An Introduction to Applied Geostatistics” by Isaaks and Srivastava (Oxford, 1989). See Chapter 19 Change of Support.

    This explains very clearly why you cannot splice together data at different measurement resolution. Like the Hockey Stick and Marcott’s uptick. Its bollocks. It also explains how the statistics, and particularly the variability and presence of extremes I changed as the measurement is made at lower resolution. the same thing happens when infilling or extrapolating grids too.

Comments are closed.