Resolution and Hockey Sticks, Part Deux: Carbon Dioxide

Guest geological perspective by David Middleton

In Part 1 of this series on resolution in signal processing, we discussed the integration of high resolution instrumental temperature records and lower resolution paleoclimate proxy data in climate reconstructions. In Part Deux, we will look at the integration of high resolution instrumental carbon dioxide records and lower resolution paleoclimate data.

Carbon Dioxide Hockey Sticks

The image below is an example of fake science.

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. 

NASA

According to the NASA narrative, the paleo-CO₂ was from the Vostok ice core…

Data: Luthi, D., et al.. 2008; Etheridge, D.M., et al. 2010; Vostok ice core data/J.R. Petit et al.; NOAA Mauna Loa CO₂ record. Some description adapted from the Scripps CO2 Program website, “Keeling Curve Lessons.”

NASA

The NOAA Mauna Loa CO₂ record would be a single data point at the same resolution of the Vostok ice core. It would be the average atmospheric concentration over the past 1,500 years, not the sharp blade of a hockey stick.

Most Antarctic ice cores are not capable of resolving century-scale CO₂ shifts.  ice cores cannot resolve CO₂ shifts that occur over durations 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 Law Dome, Antarctica DE08 ice core:

The gas enclosed in ice core bubbles is always younger than the enclosing ice. The gas-age/ice-age difference is a function of the snow accumulation rate. The higher the accumulation rate, the smaller the gas-age/ice-age difference, the shorter the gas age distribution and the higher the resolution. The bubble enclosure period for Law Dome DE08 is about 10 years, indicating a resolution of 20 years. While it’s possible that the resolution of the DE08 core is as fine as 10 years, it could also be as low as 30 years. MacFarling Meure et al. 2006 presented the highest resolution analysis of the Law Dome cores as a 20-yr spline fit. While the exact resolution is uncertain, even at 30-yr, it should “see” the Mauna Loa record and it does.

This composite Antarctic ice core record would seem to confirm that CO₂ is indeed higher than at any point in the past 800,000 years:

The composite was constructed from the following core intervals:

1. -51-1800 yr BP:’ Law Dome (Rubino et al., 2013)
2. 1.8-2 kyr BP: Law Dome (MacFarling Meure et al., 2006)
3. 2-11 kyr BP: Dome C (Monnin et al., 2001 + 2004)
4. 11-22 kyr BP: WAIS (Marcott et al., 2014) minus 4 ppmv (see text)
5. 22-40 kyr BP: Siple Dome (Ahn et al., 2014)
6. 40-60 kyr BP: TALDICE (Bereiter et al., 2012)
7. 60-115 kyr BP: EDML (Bereiter et al., 2012)
8. 105-155 kyr BP: Dome C Sublimation (Schneider et al., 2013)
9. 155-393 kyr BP: Vostok (Petit et al., 1999)
10. 393-611 kyr BP: Dome C (Siegenthaler et al., 2005)
11. 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 a 500-yr smoothing filter to the DE08 core to match Dome C, I get this:

Century scale CO₂ shifts on the order of the modern instrumental record would not be resolved by most Antarctic ice cores.

Application of a 130-yr smoothing filter indicates that it would be detected, but not resolved in the medium resolution Byrd ice core (Neftel, et al., 1988):

Somewhat like my seismic fault resolution example in Part 1, ice cores with at least a 130-yr resolution could detect the anomaly, but not fully resolve the Mauna Loa record.

Atmospheric CO₂ is almost certainly at its highest level in 2,000 years.  It may even be higher than any time in the past 5,000 years… It might actually be higher than at any point in the past 800,000 years, as routinely depicted by climate “scientists”.  However, every method of estimating pre-industrial CO₂ levels, apart from Antarctic ice cores, indicate that Late Quaternary CO₂ levels were frequently in the 300-350 ppmv range and possibly occasionally over 400 ppmv.

Greenland Ice Cores

Very little has been published about CO₂ concentrations in Greenland ice cores. Anklin et al, 1997 is the only publication that I have been able to obtain. In the following figures, I have overlaid the composite Antarctic ice core record over two images from Anklin:

Greenland generally has a much higher snow accumulation rate and therefore its ice cores are of much higher resolution than most Antarctic ice cores. As such, they should see higher and much more variable CO₂ concentrations. However, the so-called “consensus” rejects Greenland ice core CO₂ data because…

The discrepancies between the CO₂ profiles from Greenland and Antarctica can be explained by in situ production of excess CO₂ due to interactions between carbonate and acidic species…

Anklin et al, 1997

The discrepancies could also be explained by resolution differences… And the higher, more variable CO₂ concentrations of Greenland ice cores are supported by another method of estimating paleo-CO₂ concentrations.

Plant Stomata

This was the subject of my first post for WUWT back in 2010.

PLANT STOMATA
Stomata are microscopic pores found in leaves and the stem epidermis of plants. They are used for gas exchange. The stomatal density in some C3 plants will vary inversely with the concentration of atmospheric CO₂. Stomatal density can be empirically tested and calibrated to CO₂ changes over the last 60 years in living plants. 

Middleton, 2010

There’s very good agreement between plant stomata and the highest resolution segment of the composite Antarctic ice core.

The agreement deteriorates with age…

Note that two stomata chronologies indicate sharp spikes in atmospheric CO₂ near the end of the Late Pleistocene Bølling-Allerød interstadial/GI-1 (230-320, 240-430 ppmv) and the onset of the Holocene (210-330, 170-300 ppmv).

The spike at the onset of the Holocene is even supported by an example of “Chicken Little of the Sea”…

The same relationship holds true for the last Pleistocene intreglacial stage (Eemian/Sangamonian):

Conclusions

The plant stomata chronologies falsify the notion of a stable 270-280 ppmv pre-industrial atmospheric CO₂ concentration.

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.

Wagner et al., 1999

The plant stomata chronologies are reproducible…

The majority of the stomatal frequency-based estimates of CO₂ 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.

Wagner et al., 2004

The discrepancies between the Antarctic ice cores and stomata chronologies can largely be explained as functions of ice core resolution…

The discrepancies between the ice-core and stomatal reconstructions may partially be explained by varying age distributions of the air in the bubbles because of the enclosure time in the firn-ice transition zone. This effect creates a site-specific smoothing of the signal (decades for Dome Summit South [DSS], Law Dome, even more for ice cores at low accumulation sites), as well as a difference in age between the air and surrounding ice, hampering the construction of well-constrained time scales (Trudinger et al., 2003).

Kouwenberg et al., 2005

The resolution difference can be quantified…

Atmospheric CO₂ reconstructions are currently available from direct measurements of air enclosures in Antarctic ice and, alternatively, from stomatal frequency analysis performed on fossil leaves. A period where both methods consistently provide evidence for natural CO₂ changes is during the 13th century AD. The results of the two independent methods differ significantly in the amplitude of the estimated CO₂ changes (10 ppmv ice versus 34 ppmv stomatal frequency). Here, we compare the stomatal frequency and ice core results by using a firn diffusion model in order to assess the potential influence of smoothing during enclosure on the temporal resolution as well as the amplitude of the CO₂ changes. The seemingly large discrepancies between the amplitudes estimated by the contrasting methods diminish when the raw stomatal data are smoothed in an analogous way to the natural smoothing which occurs in the firn.

Van Hoof et al., 2005

The effect of resolution on the amplitude of the CO₂ signal can even be demonstrated using Antarctic ice cores…

Yet, this is all ignored and climate “scientists” continue to push this narrative…

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. 

The effects of resolution on the CO₂ signal render all but impossible to definitively state “that levels of carbon dioxide (CO₂) in the atmosphere are higher than they have been at any time in the past 400,000 years.” 

As I previously stated:

Atmospheric CO₂ is almost certainly at its highest level in 2,000 years.  It may even be higher than any time in the past 5,000 years… It might actually be higher than at any point in the past 800,000 years, as routinely depicted by climate “scientists”.  However, every method of estimating pre-industrial CO₂ levels, apart from Antarctic ice cores, indicate that Late Quaternary CO₂ levels were frequently in the 300-350 ppmv range and possibly occasionally over 400 ppmv.

From a climatic perspective, 400-500 ppmv is not significantly above a natural background which routinely rose to 300-400 ppmv in response to Earth’s natural cycles of warming.

Here is MacFarling-Meure’s higher resolution Law Dome CO₂ reconstruction, Mauna Loa (MLO) plotted on Figure 3 from Kouwenberg et al., 2005…

While it does appear that atmospheric CO₂ is currently higher than any point in the last 1,000-2,000 years, when all of the data are examined, it’s not nearly as anomalous as indicated by the Antarctic ice cores.

Higher frequency data have a lower signal-to-noise ratio than lower frequency data. In seismic data processing, we strive to preserve as much of the high frequency component as possible. In climate “science” there seems to be a tendency to disregard the high frequency component of the pre-industrial carbon dioxide record, while also disregarding or mishandling the low frequency component of the pre-industrial temperature record (Esper et al., 2005). This leads to overestimating the climate sensitivity (Lorius et al., 1990) and almost certainly underestimating atmospheric carbon dioxide’s sensitivity to temperature changes.

References

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

Anklin, M., J. Schwander, B. Stauffer, J. Tschumi, A. Fuchs, J. M. Barnola, and D. Raynaud (1997), “ CO₂ record between 40 and 8 kyr B.P. from the Greenland Ice Core Project ice core,” J. Geophys. Res., 102(C12), 26539–26545, doi: 10.1029/97JC00182.

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

Esper, J., R.J.S. Wilson,  D.C. Frank, A. Moberg, H. Wanner, & J. Luterbacher.  2005.  “Climate: past ranges and future changes”.  Quaternary Science Reviews 24: 2164-2166.

Finsinger, W. and F. Wagner-Cremer. “Stomatal-based inference models for reconstruction of atmospheric CO₂ concentration: a method assessment using a calibration and validation approach”. The Holocene 19,5 (2009) pp. 757–764

Kubota K., Yokoyama Y., Ishikawa T., Obrochta S., Suzuki A.  “Larger CO2 source at the equatorial Pacific during the last deglaciation.” (2014)  Scientific Reports,  4 , art. no. 5261.

Lorius, C., J. Jouzel, D. Raynaud, J. Hansen, and H. Le Treut, 1990: The ice-core record: Climate sensitivity and future greenhouse warming. Nature, 347, 139-145, doi:10.1038/347139a0.

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

Neftel, Albrecht, H. Oeshger, T. Staffelbach & Bernhard Stauffer. (1988). “CO₂ record in the Byrd ice core 50,000–5,000 years”. Nature. 331. 609-611. 10.1038/331609a0.

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

Rundgren et al., 2005. “Last interglacial atmospheric CO₂ changes from stomatal index data and their relation to climate variations”. Global and Planetary Change 49 (2005) 47–62.

Steinthorsdottir, Margret & Wohlfarth, Barbara & Kylander, Malin & Blaauw, Maarten & Reimer, Paula. (2013). “Stomatal proxy record of CO2 concentrations from the last termination suggests an important role for CO2 at climate change transitions.” Quaternary Science Reviews. 68. 43-58. 10.1016/j.quascirev.2013.02.003.

Van Hoof et al., 2005. “Atmospheric CO₂ during the 13th century AD: reconciliation of data from ice core measurements and stomatal frequency analysis”. Tellus (2005), 57B, 351–355.

Wagner et al., 1999. “Century-Scale Shifts in Early Holocene Atmospheric CO₂ Concentration”. Science 18 June 1999: Vol. 284. no. 5422, pp. 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