A Brief History of Atmospheric Carbon Dioxide Record-Breaking

Guest Post by David Middleton

The World Meteorological Organization (Why do I always think of Team America: World Police whenever “World” and “Organization” appear in the same title?) recently announced that atmospheric greenhouse gases had once again set a new record.

Greenhouse gases reach another new record high!

Records are made to be broken

I wonder if the folks at the WMO are aware of the following three facts:

1) The first “record high” CO2 level was set in 1809, at a time when cumulative anthropogenic carbon emissions had yet to exceed the equivalent of 0.2 ppmv CO2?

Figure 1. The Original CO2 “Hockey Stick.” CO2 emissions data from Oak Ridge National Laboratory’s Carbon Dioxide Information Analysis Center (CDIAC). The emissions (GtC) were divided by 2.13 to obtain ppmv CO2.

2) From 1750 to 1875, atmospheric CO2 rose at ten times the rate of the cumulative anthropogenic emissions…

Figure 2. Where, oh where, did that CO2 come from?

3) Cumulative anthropogenic emissions didn’t “catch up” to the rise in atmospheric CO2 until 1960…

Figure 3. It took humans over 100 years to “catch up” to nature.

The emissions were only able to “catch up” because atmospheric CO2 levels stalled at ~312 ppmv from 1940-1955.

The mid-20th century decline in atmospheric CO2

The highest resolution Antarctic ice cores I am aware of come from Law Dome (Etheridge et al., 1998), particularly the DE08 core. Over the past decade, the Law Dome ice core resolution has been improved through denser sampling and the application of frequency enhancing signal processing techniques (Trudinger et el., 2002 and MacFarling Meure et al., 2006). Not surprisingly, the higher resolution data are indicating more variability in preindustrial CO2 levels.

Plant stomata reconstructions (Kouwenberg et al., 2005, Finsinger and Wagner-Cremer, 2009) and contemporary chemical analyses (Beck, 2007) indicate that CO2 levels in the 1930′s to early 1940′s were in the 340 to 400 ppmv range and then declined sharply in the 1950’s. These findings have been rejected by the so-called scientific consensus because this fluctuation is not resolved in Antarctic ice cores. However, MacFarling Meure et al., 2006 found possible evidence of a mid-20th Century CO2 decline in the DE08 ice core…

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.

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

Figure 4. Oh where, oh where did all that carbon go?

If oceanic uptake of CO2 caused ocean acidification, shouldn’t we see some evidence of it? Shouldn’t “a large additional sink of ~3.0 PgC yr-1” (or more) from ~1940–1955 have left a mark somewhere in the oceans? Maybe dissolved some snails or a reef?

Had atmospheric CO2 simply followed the preindustrial trajectory, it very likely would have reached 315-345 ppmv by 2010…

Figure 5. Natural sources probably account for 40-60% of the rise in atmospheric CO2 since 1750.

Oddly enough, plant stomata-derived CO2 reconstructions indicate that CO2 levels of 315-345 ppmv have not been uncommon throughout the Holocene…

Figure 6. CO2 from plant stomata: Northern Sweden (Finsinger et al., 2009), Northern Spain (Garcia-Amorena, 2008), Southern Sweden (Jessen, 2005), Washington State USA (Kouwenberg, 2004), Netherlands (Wagner et al., 1999), Denmark (Wagner et al., 2002).

So, what on Earth could have driven all of that CO2 variability before humans started burning fossil fuels? Could it possibly have been temperature changes?

CO2 as feedback

When I plot a NH temperature reconstruction (Moberg et al., 2005) along with the Law Dome CO2 record, it sure looks to me as if the CO2 started rising about 100 years after the temperature started rising…

Figure 7. Temperature reconstruction (Moberg et al., 2005) and Law Dome CO2 (MacFarling Meure et al., 2006)

The rise in CO2 from 1842-1945 looks a heck of a lot like the rise in temperature from 1750-1852…

Figure 8. Possible relationship between temperature increase and subsequent CO2 rise.

The correlation is very strong. A calculated CO2 chronology yields a good match to the DE08 ice core and stomata-derived CO2 since 1850. However, it indicates that atmospheric CO2 would have reached ~430 ppmv in the mid-12th century AD.

Figure 9. CO2 calculated from Moberg temperatures (dark blue curve), Law Dome ice cores (magenta curve) and plant stomata (green, light blue and purple squares).

The mid-12th century peak in CO2 is not supported by either the ice cores or the plant stomata. The correlation breaks down before the 1830’s. However, the same break down also happens when CO2 is treated as forcing rather than feedback.

CO2 as forcing

If I directly cross plot CO2 vs. temperature with no lag time, I get a fair correlation with the post DE08 core (>1833) data and no correlation at all with pre-DE08 core (<1833) data…

Figure 10. Temperature and [CO2] have a moderate correlation since ~1833; but no correlation at all before 1833.

If I extrapolate out to about 840 ppmv CO2, I get about 3 °C of warming relative to 275 ppmv. So, I get the same amount of warming for a tripling of preindustrial CO2 that the IPCC says we’ll get with a doubling.

Figure 11. CO2 from the Law Dome DE08 core plotted against Moberg’s NH temperature reconstruction.

Based on this correlation, the equilibrium climate sensitivity to a doubling of preindustrial CO2 is ~1.5 to 2.0 °C. But, the total lack of a correlation in the ice cores older than DE08 is very puzzling.

Ice core resolution and the lack a CO2-temperature coupling before 1833

Could the lack of variability in the older (and deeper) cores have something to do with resolution? The DE08 core is of far higher resolution than pretty well all of the other Antarctic ice cores, including the deeper and older DSS core from Law Dome.

Figure 12. The temporal resolution of ice cores is dictated by the snow accumulation rate.

The amplitude of the CO2 “signal” also appears to be well-correlated with the snow accumulation rate (resolution) of the ice cores…

Figure 13. Accumulation rate vs. CO2 for various ice cores from Antarctica and Greenland.

Could it be that snow accumulation rates significantly lower than 1 m/yr simply can’t resolve century-scale and higher frequency CO2 shifts? Could it also be that the frequency degradation is also attenuating the amplitude of the CO2 “signal”?

If the vast majority of the ice cores older and deeper than DE08 can’t resolve century-scale and higher frequency CO2 shifts, doesn’t it make sense that ice core-derived CO2 and temperature would appear to be poorly coupled over most of the Holocene?

Why is it that the evidence always seems to indicate that the IPCC’s best case scenario is the worst that can happen in the real world?

Brad Plummer’s recent piece in the Washington Post featured a graph that caught my eye…

Figure 14. The IPCC’s mythical scenarios. I think the shaded area represents the greentopian range.

It appears that a “business as usual” (A1FI) will turn Earth into Venus by 2100 AD.

But, what happens if I use real data?

Let’s assume that the atmospheric CO2 level will rise along an exponential trend line until 2100.

Figure 15. CO2 projected to 560 ppmv by 2100.

I get a CO2 level of 560 ppmv, comparable to the IPCC SRES B2 emissions scenario…

Figure 16. IPCC emissions scenarios.

So, business as usual will likely lead to the same CO2 level as an IPCC greentopian scenario. Why am I not surprised?

Assuming all of the warming since 1833 was caused by CO2 (it wasn’t), 560 ppmv will lead to about 1°C of additional warming by the year 2100.

Figure 17. Projected temperature rise derived from Moberg NH temperature reconstruction and Law Dome DE08 ice core CO2.
Projected Temp. Anom. = 2.6142 * ln(CO2) – 15.141

How does this compare with the IPCC’s mythical scenarios? About as expected. The worst case scenario based on actual observations is comparable to the IPCC’s best case, greentopian scenario…

Figure 18. Projected temperature rise derived from Moberg NH temperature reconstruction and Law Dome DE08 ice core CO2 indicates that the IPCC’s 2°C “limit” will not be exceeded.

Conclusions

  • Atmospheric CO2 concentration records were being broken long before anthropogenic emissions became significant.
  • Atmospheric CO2 levels were rising much faster than anthropogenic emissions from 1750-1875.
  • Anthropogenic emissions did not “catch up” to atmospheric CO2 until 1960.
  • The natural carbon flux is much more variable than the so-called scientific consensus thinks it is.
  • The equilibrium climate sensitivity (ECS) cannot be more than 2°C and is probably closer to 1°C.
  • The worst-case scenario based on the evidence is comparable to the IPCC’s most greentopian, best-case scenario.
  • Ice cores with accumulation rates less than 1m/yr are not useful for ECS estimations.

The ECS derived from the Law Dome DE08 ice core and Moberg’s NH temperature reconstruction assumes that all of the warming since 1833 was due to CO2. We know for a fact that at least half of the warming was due to solar influences and natural climatic oscillations. So the derived 2°C is more likely to be 1°C. Since it is clear that about half of the rise from 275 to 400 ppmv was natural, the anthropogenic component of that 1°C ECS is probably less than 0.7°C.

The lack of a correlation between temperature and CO2 from the start of the Holocene up until 1833 and the fact that the modern CO2 rise outpaced the anthropogenic emissions for about 200 years leads this amateur climate researcher to concluded that CO2 must have been a lot more variable over the last 10,000 years than the Antarctic ice core indicate.

Appendix I: Another Way to Look at the CO2 growth rate

In Figure 15 I used the Excel-calculated exponential trend line to extrapolate the MLO CO2 time series to the end of this century. If I extrapolate the emissions and assume 55% of emissions remain in atmosphere, I get ~702 ppmv by the end of the century, with an additional 0.6°C of warming. A total warming of 2.5°C above “preindustrial.” Even this worse than worst case scenario results in about 1°C less warming than the A1B reference scenario. It falls about mid-way between A1B and the top of the greentopian range.

Appendix II: CO2 Records, the Early Years

Whenever CO2 records are mentioned or breathtaking pronouncements like, “Carbon dioxide at highest level in 800,000 years” are made, I always like to take a look at those “records” in a geological context. The following graphs were generated from Bill Illis’ excellent collection of paleo-climate data.

Greenhouse gases reach another new record high! Or did they? The “Anthropocene” doesn’t look a heck of a lot different than the prior 25 million years… Apart from being a lot colder.

The “Anthropocene’s” CO2 “Hockey Stick” looks more like a needle in a haystack from a geological perspective. And it looks to me as if Earth might be on track to run out of CO2 in about 25 million years.

One of my all-time favorites! Note the total lack of correlation between CO2 and temperature throughout most of the Phanerozoic Eon.

In the following bar chart I grouped CO2 by geologic period. The Cambrian through Cretaceous are drawn from Berner and Kothavala, 2001 (GEOCARB), the Tertiary is from Pagani, et al. 2006 (deep sea sediment cores), the Pleistocene is from Lüthi, et al. 2008 (EPICA C Antarctic ice core), the “Anthropocene” is from NOAA-ESRL (Mauna Loa Observatory) and the CO2 starvation is from Ward et al., 2005.

“Anthropocene” CO2 levels are a lot closer to the C3 plant starvation (Ward et al., 2005) range than they are to most of the prior 540 million years.

[SARC ON] I thought about including Venus on the bar chart; but I would have had to use a logarithmic scale. [SARC OFF]

Appendix III: Plant Stomata-Derived CO2

The catalogue of peer-reviewed papers demonstrating higher and more variable preindustrial CO2 levels is quite impressive and growing. Here are a few highlights:

Wagner et al., 1999. Century-Scale Shifts in Early Holocene Atmospheric CO2 Concentration. Science 18 June 1999: Vol. 284 no. 5422 pp. 1971-1973

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.

The ice cores cannot resolve CO2 shifts that occur over periods of time shorter than twice the bubble enclosure period. This is basic signal theory. The assertion of a stable pre-industrial 270-280 ppmv is flat-out wrong.

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…

It is possible that a number of the short-term fluctuations recorded using the stomatal methods cannot be detected in ice cores, such as Dome Concordia, with low ice accumulation rates. 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.

Not even the highest resolution ice cores, like Law Dome, have adequate resolution to correctly image the MLO instrumental record.

Kouwenberg et al., 2005. Atmospheric CO2 fluctuations during the last millennium reconstructed by stomatal frequency analysis of Tsuga heterophylla needles. Geology; January 2005; v. 33; no. 1; p. 33–36…

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).

Stomatal reconstructions are reproducible over at least the Northern Hemisphere, throughout the Holocene and consistently demonstrate that the pre-industrial natural carbon flux was far more variable than indicated by the ice cores.

Wagner et al., 2004. Reproducibility of Holocene atmospheric CO2 records based on stomatal frequency. Quaternary Science Reviews. 23 (2004) 1947–1954…

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.

The Antarctic ice cores lack adequate resolution because the firn densification process acts like a low-pass filter.

Van Hoof et al., 2005. Atmospheric CO2 during the 13th century AD: reconciliation of data from ice core measurements and stomatal frequency analysis. Tellus 57B (2005), 4…

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.

The derivation of equilibrium climate sensitivity (ECS) to atmospheric CO2 is largely based on Antarctic ice cores. The problem is that the temperature estimates are based on oxygen isotope ratios in the ice itself; while the CO2 estimates are based on gas bubbles trapped in the ice.

The temperature data are of very high resolution. The oxygen isotope ratios are functions of the temperature at the time of snow deposition. The CO2 data are of very low and variable resolution because it takes decades to centuries for the gas bubbles to form. The CO2 values from the ice cores represent average values over many decades to centuries. The temperature values have annual to decadal resolution.

The highest resolution Antarctic ice core is the DE08 core from Law Dome.

The IPCC and so-called scientific consensus assume that it can resolve annual changes in CO2. But it can’t. Each CO2 value represents a roughly 30-yr average and not an annual value.

If you smooth the Mauna Loa instrumental record (red curve) and plant stomata-derived pre-instrumental CO2 (green curve) with a 30-yr filter, they tie into the Law Dome DE08 ice core (light blue curve) quite nicely…

The deeper DSS core (dark blue curve) has a much lower temporal resolution due to its much lower accumulation rate and compaction effects. It is totally useless in resolving century scale shifts, much less decadal shifts.

The IPCC and so-called scientific consensus correctly assume that resolution is dictated by the bubble enclosure period. However, they are incorrect in limiting the bubble enclosure period to the sealing zone. In the case of the core DE08 they assume that they are looking at a signal with a 1 cycle/1 yr frequency, sampled once every 8-10 years. The actual signal has a 1 cycle/30-40 yr frequency, sampled once every 8-10 years.

30-40 ppmv shifts in CO2 over periods less than ~60 years cannot be accurately resolved in the DE08 core. That’s dictated by basic signal theory. Wagner et al., 1999 drew a very hostile response from the so-called scientific consensus. All Dr. Wagner-Cremer did to them was to falsify one little hypothesis…

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.

[…]

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 (⁠23⁠).

The plant stomata pretty well prove that Holocene CO2 levels have frequently been in the 300-350 ppmv range and occasionally above 400 ppmv over the last 10,000 years.

The incorrect estimation of a 3°C ECS to CO2 is almost entirely driven the assumption that preindustrial CO2 levels were in the 270-280 ppmv range, as indicated by the Antarctic ice cores.

The plant stomata data clearly show that preindustrial atmospheric CO2 levels were much higher and far more variable than indicated by Antarctic ice cores. Which means that the rise in atmospheric CO2 since the 1800’s is not particularly anomalous and at least half of it is due to oceanic and biosphere responses to the warm-up from the Little Ice Age.

Kouwenberg concluded that the CO2 maximum ca. 450 AD was a local anomaly because it could not be correlated to a temperature rise in the Mann & Jones, 2003 reconstruction.

As the Earth’s climate continues to not cooperate with their models, the so-called consensus will eventually recognize and acknowledge their fundamental error. Hopefully we won’t have allowed decarbonization zealotry to bankrupt us beforehand.

Until the paradigm shifts, all estimates of the pre-industrial relationship between atmospheric CO2 and temperature derived from Antarctic ice cores will be wrong, because the ice core temperature and CO2 time series are of vastly different resolutions. And until the “so-called consensus” gets the signal processing right, they will continue to get it wrong.

References

Anklin, M., J. Schwander, B. Stauffer, J. Tschumi, A. Fuchs, J.M. Barnola, and D. Raynaud. 1997. CO2 record between 40 and 8kyr B.P. from the Greenland Ice Core Project ice core. Journal of Geophysical Research 102:26539-26545.

Barnola et al. 1987. Vostok ice core provides 160,000-year record of atmospheric CO2.

Nature, 329, 408-414.

Berner, R.A. and Z. Kothavala, 2001. GEOCARB III: A Revised Model of Atmospheric CO2 over Phanerozoic Time, American Journal of Science, v.301, pp.182-204, February 2001.

Boden, T.A., G. Marland, and R.J. Andres. 2012. Global, Regional, and National Fossil-Fuel CO2 Emissions. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tenn., U.S.A. doi 10.3334/CDIAC/00001_V2012

Etheridge, D.M., L.P. Steele, R.L. Langenfelds, R.J. Francey, J.-M. Barnola and V.I. Morgan. 1998. Historical CO2 records from the Law Dome DE08, DE08-2, and DSS ice cores. In Trends: A Compendium of Data on Global Change. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tenn., U.S.A.

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

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

Garcıa-Amorena, I., F. Wagner-Cremer, F. Gomez Manzaneque, T. B. van Hoof, S. Garcıa Alvarez, and H. Visscher. 2008. CO2 radiative forcing during the Holocene Thermal Maximum revealed by stomatal frequency of Iberian oak leaves. Biogeosciences Discussions 5, 3945–3964, 2008.

Illis, B. 2009. Searching the PaleoClimate Record for Estimated Correlations: Temperature, CO2 and Sea Level. Watts Up With That?

Indermühle A., T.F. Stocker, F. Joos, H. Fischer, H.J. Smith, M. Wahlen, B. Deck, D. Mastroianni, J. Tschumi, T. Blunier, R. Meyer, B. Stauffer, 1999, Holocene carbon-cycle dynamics based on CO2 trapped in ice at Taylor Dome, Antarctica. Nature 398, 121-126.

Jessen, C. A., Rundgren, M., Bjorck, S. and Hammarlund, D. 2005. Abrupt climatic changes and an unstable transition into a late Holocene Thermal Decline: a multiproxy lacustrine record from southern Sweden. J. Quaternary Sci., Vol. 20 pp. 349–362. ISSN 0267-8179.

Kouwenberg, LLR. 2004. Application of conifer needles in the reconstruction of Holocene CO2 levels. PhD Thesis. Laboratory of Palaeobotany and Palynology, University of Utrecht.

Kouwenberg, LLR, Wagner F, Kurschner WM, Visscher H (2005) Atmospheric CO2 fluctuations during the last millennium reconstructed by stomatal frequency analysis of Tsuga heterophylla needles. Geology 33:33–36

Ljungqvist, F.C.2009. Temperature proxy records covering the last two millennia: a tabular and visual overview. Geografiska Annaler: Physical Geography, Vol. 91A, pp. 11-29.

Ljungqvist, F.C. 2010. A new reconstruction of temperature variability in the extra-tropical Northern Hemisphere during the last two millennia. Geografiska Annaler: Physical Geography, Vol. 92 A(3), pp. 339-351, September 2010. DOI: 10.1111/j.1468-0459.2010.00399.x

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, Vol. 453, pp. 379-382, 15 May 2008. doi:10.1038/nature06949

MacFarling Meure, C., D. Etheridge, C. Trudinger, P. Steele, R. Langenfelds, T. van Ommen, A. Smith, and J. Elkins (2006), Law Dome CO2, CH4 and N2O ice core records extended to 2000 years BP, Geophys. Res. Lett., 33, L14810, doi:10.1029/2006GL026152.

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

Moberg, A., D.M. Sonechkin, K. Holmgren, N.M. Datsenko and W. Karlén. 2005.

Highly variable Northern Hemisphere temperatures reconstructed from low- and high-resolution proxy data. Nature, Vol. 433, No. 7026, pp. 613-617, 10 February 2005.

Morice, C.P., J.J. Kennedy, N.A. Rayner, P.D. Jones (2011), Quantifying uncertainties in global and regional temperature change using an ensemble of observational estimates: the HadCRUT4 dataset, Journal of Geophysical Research, accepted.

Pagani, M., J.C. Zachos, K.H. Freeman, B. Tipple, and S. Bohaty. 2005. Marked Decline in Atmospheric Carbon Dioxide Concentrations During the Paleogene. Science, Vol. 309, pp. 600-603, 22 July 2005.

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.

Smith, H. J., Fischer, H., Mastroianni, D., Deck, B. and Wahlen, M., 1999, Dual modes of the carbon cycle since the Last Glacial Maximum. Nature 400, 248-250.

Trudinger, C. M., I. G. Enting, P. J. Rayner, and R. J. Francey (2002), Kalman filter analysis of ice core data 2. Double deconvolution of CO2 and δ13C measurements, J. Geophys. Res., 107(D20), 4423, doi:10.1029/2001JD001112.

Van Hoof et al., 2005. Atmospheric CO2 during the 13th century AD: reconciliation of data from ice core measurements and stomatal frequency analysis. Tellus 57B (2005), 4

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

Wagner F, Aaby B, Visscher H, 2002. Rapid atmospheric CO2 changes associated with the 8200-years-B.P. cooling event. Proc Natl Acad Sci USA 99:12011–12014.

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

Ward, J.K., Harris, J.M., Cerling, T.E., Wiedenhoeft, A., Lott, M.J., Dearing, M.-D., Coltrain, J.B. and Ehleringer, J.R. 2005. Carbon starvation in glacial trees recovered from the La Brea tar pits, southern California. Proceedings of the National Academy of Sciences, USA 102: 690-694.

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Nice (and very interesting) paper.
Question. How does this data work with respect to the primary carbon cycle model? It looks like it would completely destroy it (to me). That’s worth a paper all by itself.
rgb

GlynnMhor

If we can deter our feckless politicians from being too severe with their panic-stricken carbon-strangulation policies, another lustrum or two of little or no warming will lead them to turn away from the economically ruinous direction that special interest groups have been promoting.

Then there is Prof. Jaworowski’s compilation of direct, chemical measurement of CO2 concentrations from the 19th & early 20th century, showing variability & some readings higher than now:
http://www.john-daly.com/zjiceco2.htm
Of course parts of the world already burning fossil fuels then were likeliest to be measured, but similarly Mauna Loa is downwind from the world’s most active volcano.
Dr. Ball’s comments warrant re-reading:
http://www.friendsofscience.org/assets/documents/FoS%20Pre-industrial%20CO2.pdf

richardscourtney

David Middleton:
Thankyou. Well said.
Richard

Thanks, David. Excellent work!
The god of CO2 is proving to be very minor, or not to be at all.

Bill Illis

Lots of great stuff in there David.
Here is another which is very interesting to add to it, the amount of CO2 in ppm that is naturally being sequestered by Plants, Oceans and Soils (and soils have underestimated in this regard, particularly grassland/Zero Till agricultural soils).
This is an exponential curve (which is technically more exponential than our emissions trajectory currently is) and it might also show how much natural variability there was before our emissions really started increasing in the 1930s.
http://s17.postimage.org/9j3ef7vlb/Net_Natural_Absorp_Human_CO2_Emis_1750.png

It were only about science the resolution and answers would be quite straight forward. It is not about that and never has been. First it was the advance of the glaciers then the AGW, next…it simply matters not when you are attempting to gain power. One of the most powerful motivators is religious belief. We simply make a religion out of something that will deliver us power by motivating believers by playing to there fears. The best part about using a religious or theocratic modivation is most of the worlds population is conditioned to unquestionably accept the dogma.

Slabadang

Well!
Salbys and Humlums work poitns att hte temperature drives the co2 levels and not the other way around. The IPCC has obviously misinterpretated the carbon cycle. One third of all the human contribution of co2 i ssonce 1998 … why doesnt that show at Mauna Loa measurements? Where is the “hockey stick” ?
[please edit and resubmit. Mod]

DeNihilist

Congradulation David, you out-tisdaled Mr. Tisdale.
Very well written. Maybe you and Dr.Brown can convene and author a paper for publication together?

Reblogged this on contrary2belief and commented:
Ice cores “capture” CO2 … but over the span of several decades to a century, over which diffusion with surface smooths out any “bumps” in concentration

John West

Very nice! Good work.
I wonder however if stomata derived CO2 really captures background CO2 without local concentration influences.

richardscourtney

John West:
At December 7, 2012 at 5:21 pm you say
“I wonder however if stomata derived CO2 really captures background CO2 without local concentration influences.”
Yes, the stomata data does.
Stomatal density is calibrated to atmospheric CO2 experimentally. Therefore, it is observed that the stomata data do record background CO2 concentration.
The leaves grow stomata to match optimum CO2 concentration for the plant’s growth. Upon achieving that stomatal density they do not grow more stomata. And in the past the local human influences on atmospheric CO2 concentration were trivial at the sites from which the preserved leaves are collected.
Importantly, David Middleton compares stomatal data to ice core data. There is no more reason to think ice cores capture the background CO2 concentration better than the stomata and there are several other problems with the ice core data (some of which are mentioned by David Middleton).
Richard

richardscourtney

Bernd Felsche:
At December 7, 2012 at 5:15 pm you say
“Reblogged this on contrary2belief and commented:
Ice cores “capture” CO2 … but over the span of several decades to a century, over which diffusion with surface smooths out any “bumps” in concentration”
The smoothing is not merely diffusion. The fern takes several years to solidify to form solid ice: the IPCC suggests 83 years and in his above article David Middleton suggests 30-40 years. During that time the fern has open porosity and atmospheric pressure varies with the weather. The pressure variations will act to expand and contract the entrained air and, thus, induce physical mixing of air entrained in the firn throughout that time.
Richard

Jeff L

David,
A very thoughtful post as usual.
Re CO2 as forcing: Do you have the computational capability to do a cross correlation function between CO2 & temp data? It could be a powerful display. If you can demonstrate a positive lag of CO2 vs temps (as has been visually established with the Vostok core data), it would be a powerful argument that CO2 concentration is driven by temps & not the other way around – at least over longer time scales (per your suggestion in figure 8). As has been stated many times before here, correlation is not causation, but in this case , we have a physical model to suggest this would be the case – ie exsolution of CO2 gas with warming sea water. Because the heat capacity of the atmosphere is << the ocean, it takes a long time before atmospheric warming translates to ocean warming which translates to exsolution of CO2 from the oceans, translating to higher CO2 in the atmosphere, thus resulting in a positive lag of CO2 relative to temps . A simple model which is thermodynamically & chemically possible to explain the relationship.
For those who aren't following, think about a Cold coke vs a hot Coke. The bubbles in Coke are CO2 – if you have a cold Coke, the bubbles stay in the drink – it's not as fizzy. A hot Coke, the bubbles all come out & it's super fizzy – exsolution of the CO2 from the liquid. In general, cold liquid can disolve more CO2 than warm liquid so warm the Coke & the CO2 comes out. Same thing with the oceans – warm the oceans & the CO2 comes out thus why CO2 could / should have a positive lag relative to air temps.
I would love to see some additional follow up on this idea.

John West

@ richardscourtney
Thanks for the info. Completely agree there’s serious problems with ice core CO2 record as paleo-climate-gospel, most of which David expertly lays bare above.

LazyTeenager

The IPCC and so-called scientific consensus assume that it can resolve annual changes in CO2. But it can’t. Each CO2 value represents a roughly 30-yr average and not an annual value.
———–
That does not sound right. I don’t see the slightest evidence that anyone believes that the ice cores have one year resolution.
And this banging on about the IPCC is just fudging. The IPCC organises the production of the report, it does not write the reports. The reports are reviews of the scientific iterature written by researchers. So the actual quarrel is with the evidence collected by scientists.
So David the amateur should admit he disagrees with the evidence collected by professionals. That would be more honest than trying to draw caricatures based on the conspiracy theory reflex.

D Böehm

Lazy T says:
“I don’t see the slightest evidence that anyone believes that the ice cores have one year resolution.”
There is plenty that Lazy does not see. And…
“The IPCC… does not write the reports. The reports are reviews of the scientific iterature written by researchers. So the actual quarrel is with the evidence collected by scientists.”
Ha-ha. I suppose Lazy actually believes the UN/IPCC reports are written by peer reviewed scientists. Because Lazy states:
“…David the amateur should admit he disagrees with the evidence collected by professionals.”
Lazy actually believes that WWF reports constitute peer reviewed science written by ‘researchers’. But of course, we know better: NGOs and QUANGOs write a large part of the UN/IPCC reports, and the IPCC pretends it is science, instead of the greenie propaganda that it really is.

Mooloo

I have serious issues with Figure 13. Any data like that will yield at decent R-squared even when absolutely no signal is present.
Without some signal in the individual plots I believe your regression line is meaningless.
See “Fisher Iris” for a famous example of how regression cannot be used in cases like this.

Alan Wilkinson

@Mooloo, the GRIP data seems to be the odd one out in not showing a correlation.

Regarding, “Plant stomata reconstructions (Kouwenberg et al., 2005, Finsinger and Wagner-Cremer, 2009) and contemporary chemical analyses (Beck, 2007) indicate that CO2 levels in the 1930′s to early 1940′s were in the 340 to 400 ppmv range…”
There is a good reason why these are inconsistent with CO2 levels indicated in ice cores. These high readings were taken in surface air where the biosphere was active and affects CO2.
The biosphere sinks CO2 mainly when there is sunshine, and sources CO2 mainly when there is not. When there is sunshine, there is also more likely to be convection that favors ixing oof surface air with the general lower troposphere. When there is no sunshine, surface air is more likely to be isolated from the general upper troposphere.
This effect can be seen in the Wisconsin Tower story:
http://www.esrl.noaa.gov/gmd/ccgg/about/co2_measurements.html
Figure 5A shows many CO2 readings deviating greatly upward from general atmospheric levels, but downward deviations tend to be small.

P. Solar

Lazy says: “And this banging on about the IPCC is just fudging. The IPCC organises the production of the report, it does not write the reports. The reports are reviews of the scientific iterature written by researchers. So the actual quarrel is with the evidence collected by scientists. ”
Seriously, where have you been for the last 5 years. You’re a regular commentator here, so assuming you read as well as posting comments you know damn well a lot of sources are grey literature , not peer-reviewed and you also know that the IPCC process produces the Summary for Policy Makers three months BEFORE it produces the detailed scientific reports.
It is also well documented that Ben Santer unilaterally modified agreed content for the chapter of which he was leading author.
The myth that IPCC reports are “scientific” reports got busted long ago and you know it. That is why people are banging on about the IPCC fudging the science.

Here’s something I saw in Figure 3: Atmospheric CO2 gain outpaced anthropogenic emissions until the late 1890’s. After that, the atmosphere gained CO2 more slowly than human activity produced CO2. This means that nature added CO2 to the atmosphere until the late 1890’s, and removed CO2 from the atmosphere since.

P. Solar

A very interesting article but you go off the rails a bit at times:
>>
CO2 as forcing
The rise in CO2 from 1842-1945 looks a heck of a lot like the rise in temperature from 1750-1852…
>>
HUH? If you looked at the price of banana or anything else you could almost certainly find some arbitrary segment which looked “a heck of a lot like ” part of the temp record to a similar degree. I really don’t think that has any meaning.
However, the point you make about closing time of ice is fundamentally important. As is sampling interval. Here’s a snip from the beginning of an analysis of the Vostok ice core:
[sourcecode]
### ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/vostok/co2nat.txt
Gas age CO2 (ppmv)
2342 284.7
3634 272.8
3833 268.1
6220 262.2
7327 254.6
[/sourcecode]
whole civilisations have come and gone quicker that that.Yet how often is this data used to tell us that current CO2 levels have not been seen in the last 400,000 years or some such.
Comparing this sort of data to an annual CO2 level is about as ‘apples and oranges’ as you can get, but this will not be seen or understood by non scientific readers. eg:
http://en.wikipedia.org/wiki/File:Co2-temperature-plot.svg
The poster who created this deception is Kiwi who claims a PhD in maths:
[i]
User:Leland McInnes
From Wikipedia, the free encyclopedia
Info
Flag of New Zealand.svg This user is associated with New Zealand.
Hi, I’m a mathematician, who recently finished my Ph.D. on profinite Lie rings.
[/i]
Well I suppose in creating another ring of profinite lies, he’s pretty much qualified.

P. Solar

figure 3: “The emissions were only able to “catch up” because atmospheric CO2 levels stalled at ~312 ppmv from 1940-1955.”
This flat may be artificial. There is considerable uncertainty in estimating the “age” of any sample at a give depth in the ice core. At lot of the gas age vs depth calibrations get forced to agree with with MLO observations when the data as derived does not in fact match.
I suspect what you have noted here is a data processing fudge to make the two agree. Welcome to climate “data”.

P. Solar

Here is a log plot graph I did a couple of years back of CO2 using emission data scaled to fit MLO. This implies a questionable assumption that the proportion of emissions assimilated by the biosphere is constant over time (matched to MLO period) and that there is no significant natural variation.
http://i45.tinypic.com/fx9c04.png
The log plot shows growth of CO2 can be typified by three different exponential growth periods which are represented by straight sections in a log plot.
Using this scaling scheme projects the earlier growth rate of 19th c. back to a level of 295 ppm
I considered it meaningless to project out to 2100 but my 2050 value seems close to what is shown in figure 15 above.

P. Solar

comparing to this plot I posted here yesterday suggests the recent (post WWII) emissions would be better split into two different growth rates.
http://i50.tinypic.com/2n83l1d.png
The growth used for projection in my last post represents the whole period with one slope and the slight divergence at the end is already evident. So even if current global growth rates are maintained 2050 CO2 levels will probably be somewhat less the 462ppm of that projection.
http://i45.tinypic.com/fx9c04.png

Thank you for your elucidation, richardscourtney.
I used the term “diffusion” in a broad sense (albeit incorrectly) to satisfy the urge to comment at least a little while reblogging.

DirkH

LazyTeenager says:
December 7, 2012 at 8:02 pm
“And this banging on about the IPCC is just fudging. The IPCC organises the production of the report, it does not write the reports. The reports are reviews of the scientific iterature written by researchers. So the actual quarrel is with the evidence collected by scientists. ”
How do you explain the resignation of Dr. Landsea?

P. Solar says:
December 7, 2012 at 11:05 pm

Lazy says: “And this banging on about the IPCC is just fudging. The IPCC organises the production of the report, it does not write the reports. The reports are reviews of the scientific iterature written by researchers. So the actual quarrel is with the evidence collected by scientists. ”

Seriously, where have you been for the last 5 years. You’re a regular commentator here, so assuming you read as well as posting comments you know damn well a lot of sources are grey literature , not peer-reviewed and you also know that the IPCC process produces the Summary for Policy Makers three months BEFORE it produces the detailed scientific reports.
It is also well documented that Ben Santer unilaterally modified agreed content for the chapter of which he was leading author.
…………………..
DirkH says:
December 8, 2012 at 2:19 am
How do you explain the resignation of Dr. Landsea?

Donna LaFramboise’s book, The Delinquent Teenager, peels back the curtain and reveals what goes on inside the IPCC process, namely:
The IPCC DOES write the reports, in that its lead authors select what material they deign worthy of inclusion, and what it may soft-pedal or ignore. Lots of alarmist gray literature is deemed worthy of citation as supporting evidence; no skeptical gray literature is.
Those honchos may also ignore the comments of expert reviewers. (Lindzen’s comments on the first two reports were ignored–that’s why he (and other skeptics) refused to participate in subsequent Reports.) (This is how Glaciergate occurred—the coordinating lead author of the Asia group, Lal, ignored comments pointing out its error, presumably because he thought it made a good story to motivate governments to act. He also ignored a warning letter from Georg Kaser after the fact, claiming he never received it. Maybe the dog ate it.)
Most important, the selection of the coordinating lead authors is done completely secretly by the IPCC bureaucracy (likely with informal input from The Team), from nominations made by governments (in effect by their environmental agencies). They in turn select the lead authors, who select the authors. With the IPCC insiders able to determine the Input (i.e., the key personnel who will produce it), the nature of the Output (alarmism) is guaranteed.

mkelly

P.Solar your snippet of the ice age vs CO2 shows the lack of correlation of T with CO2. Seven thousand years ago the temperature was warmer than now with a 100 ppm less CO2. The reason it was warmer then is not absolutely known so there is no way of knowing if it is happening or could again.

Doubting Rich

Anyone who thinks that ice cores are suitable for measuring atmospheric constituents with enough resolution to say what happened in the 20th century has no idea how ice forms. It is blindingly obvious that in the layers there will be gas mixing before the bubbles become sealed, and that decade-scale events are not going to resolve.

Bart

I really cannot understand why people cannot see the obvious when I point out the relationship. I can only guess that most people are simply not very comfortable with the calculus of differential equations.
To a very high degree of accuracy, the relationship is
dCO2/dt = k*(T – To)
where To is the equilibrium level which changes slowly on average, and k is a coupling constant, though it may also change slowly on average over time. T is the globally averaged temperature anomaly, and dCO2/dt is the derivative of CO2 concentration. I have mathematically derived one way in which such a relationship could arise from deep ocean upwelling of carbon rich waters on another thread, and there may well be others in a dynamic system which depends critically on the differential between continuous carbon fluxes into and out of the system.
It’s a done deal. Temperature controls CO2 level, and CO2 level has a negligible impact on temperatures. There is no viable alternative explanation.

D Böehm

Bart says:
“Temperature controls CO2 level, and CO2 level has a negligible impact on temperatures. There is no viable alternative explanation.”
Exactly right. ∆CO2 follows ∆T, as this chart clearly shows. But there is no corresponding chart showing that ∆T follows ∆CO2. There are no such measurements available, but not for lack of trying to find them. AGW measurements simply do not exist, meaning one of two things: either AGW is so insignificant that it cannot be measured, or AGW does not exist.
One thing is certain: if CO2 causes any global warming, its effect must be extremely minuscule. Therefore, AGW is so insignificant that it can be completely disregarded for all practical purposes. The country should waste no more money on the AGW false alarm.

Bart

D Böehm says:
December 8, 2012 at 12:02 pm
“Exactly right. ∆CO2 follows ∆T, as this chart clearly shows.”
With, you will note, a 90 degree phase lag (1/4 wavelength) characteristic of an integrated quantity.

David A. Evans

Lazy Teenager…

So David the amateur should admit he disagrees with the evidence collected by professionals. That would be more honest than trying to draw caricatures based on the conspiracy theory reflex.

Does this mean nothing to you, other than tainted?

I have been a geoscientist in the evil oil and gas industry for almost 30 years.

Are you saying that David Middleton is not a professional?
He may not be a professional academic but in my eyes that’s a plus. Screw up in his trade, there are financial consequences and you don’t escape them if you’re the one that screwed up.
In academia, screw up and especially if you have tenure, no consequences.
get real!
DaveE.

David, there are a lot of problems with your story.
To begin with, the stomata data:
Stomata, by definition, are from land plants. These grow in an atmosphere largely enhanced in CO2, compared to the “background” CO2 levels measured in ice cores, far away from any disturbances. Stomata (index) data reflect the average CO2 levels of the direct neighbourhood of the plants in the previous growing season.
The positive CO2 bias is dealt with by calibrating the SI data over the past century to atmospheric and ice core CO2 measurements. So far so good. The main problem is that you have not the slightest control over the local CO2 data over previous centuries. Take e.g. the change in landscape in The Netherlands over the last millennium: from sea to land from heather to forests and from agriculture to industry. All in the main wind directions of the main place of their oak SI data (St. Odiliënberg in SE Netherlands). Even the main wind direction may have changed between the MWP and LIA and back, influencing local CO2 levels…
Last but not least: whatever you may think about the ice cores, even if there was a lot of migration over time (which is not the case), that does influence the resolution, but that doesn’t change the average CO2 level over the resolution period. So if you find in average higher levels of CO2 in the stomata data of the past, then the stomata data are simply wrong…
BTW, the resolution of the 1.000 year long Law Dome DSS core is about 20 years, with an accuracy of 1.2 ppmv (1 sigma). Thus any one-year peak of 30 ppmv or a sustained change of 3 ppm over 20 years would be detected in that ice core…
And BTW, the SI data (and about all other proxies and ice cores) contradict the late Ernst Beck’s historical CO2 data analysis: there is no “peak” of 80 ppmv in the period around 1942…
Then the CO2 levels in the ice cores which don’t follow the human emissions in the begin period.
Well, if you have 2 main variables which influence CO2 levels, then you should look at both. Human emissions are not the only cause of the CO2 rise: temperature has also its influence. Not an extreme one, but in average some 4-5 ppmv/°C for short term variations in temperature up to 8 ppmv/°C for very long term changes (from multi-decades to multi-millennia over at least the past 800 kyears). Thus if you see an increase of CO2 while the emissions were still very low in the 19th century (as in your fig. 1 and 2), that simply is related to temperature (and other natural variability), not to human CO2. Even nowadays, the same short term variability (over 1-3 years time) is seen around the trend, directly related to fast, but limited in capacity, processes in the sea surface and vegetation.
Figure 3 is a triggy one: human CO2 is not “catching up” but is additional to the point where it was already driven by nature (temperature or other means). So your starting point is wrong. Human emissions start to be more or less significant from 1850 on, thus you should start the human accumulation at the CO2 levels of 1850, not of 1750. Or from 1900 on, as between 1850 and 1900, the natural variability still was more important than the human contribution. If you start from 1900, that gives a complete different picture:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/temp_emiss_increase.jpg
From about 1940 on, the cumulative emissions are overtaking the natural variability.
From a process view:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/acc_co2_1900_2004.jpg
or even for the ice core 1900-1960 period:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/acc_co2_1900_1959.jpg
compare that to the influence of temperature in the same periods:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/temp_co2_1900_2004.jpg
and
http://www.ferdinand-engelbeen.be/klimaat/klim_img/temp_co2_1900_1959.jpg
Short term variability through temperature: yes, at 4-5 ppmv/°C. Modest long term changes of 8 ppmv/°C. But that is all. The rest is from human emissions…
Then:
If oceanic uptake of CO2 caused ocean acidification, shouldn’t we see some evidence of it?
There are no direct measurements from the early period, but there are a few long-term series from recent times at Hawaii and the Bermuda’s. Which show a rise in total carbon of the oceans, a decrease in d13C and a calculated drop in pH. Any variable in seawater can be calculated if a few others are known:
http://www.bios.edu/Labs/co2lab/research/IntDecVar_OCC.html
That simply shows that oceanic degassing is not the cause of the increase in the atmosphere, it is the opposite. Frequent ships surveys over many trajects show the same trends in all oceans.
And final: temperature changes of the oceans only give 16 ppmv/°C increase by Henry’s Law. Nothing more. Even less at equilibrium, as vegetation reacts in opposite way. Thus the maximum 1°C increase in temperature since the LIA did increase the CO2 levels with maximum 8 ppmv. That is all, the rest is caused by the human emissions.

P. Solar says:
December 8, 2012 at 12:16 am
This flat may be artificial. There is considerable uncertainty in estimating the “age” of any sample at a give depth in the ice core. At lot of the gas age vs depth calibrations get forced to agree with with MLO observations when the data as derived does not in fact match.
In the case of the Law Dome ice core, there is very little uncertainty of the age of ice (by counting the thick layers) and air composition, as the air composition was measured top down in firn until closing depth. The air composition could be directly compared with atmospheric measurements at the South Pole. There was even an overlap of 20 years between the ice core measurements and the direct measurements:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/law_dome_overlap.jpg

D Böehm

This conclusion is missing from most of Ferdinand’s Engelbeen’s comments:
“In my opinion even a doubling would have little impact, as clouds are a negative feedback (while all current GCM’s include clouds as a positive feedback!), thus a doubling of CO2 would have only moderate (and thus globally positive) effects.
~ Ferdinand Englebeen, WUWT, 11-25-10

That answers the central question in the debate, no? The question is whether the rise in CO2 is harmful, or beneficial. The alarmist crowd always takes the unalterable position that a rise in “carbon” is entirely a bad thing. They cannot ever admit that there could be anything good about the rise in carbon dioxide, a minor trace gas and plant fertilizer that is measured in parts per million.
Over the past decade we have seen that the planet agrees with Ferdinand Engelbeen [and with the 31,400+ scientists who co-signed the OISM Petition], and not with the alarmist crowd. The rise in CO2 has been entirely harmless, and provably beneficial. It turns out that the added CO2 is better for the biosphere, and no global harm from more CO2 has ever been observed.
Ferdinand is very knowledgeable on the subject of CO2, and he is always patient with his explanations. The only thing I would ask is that he take that final logical step in his comments, and point out that numerous empirical observations support the hypothesis that the added CO2 is harmless, and beneficial to the biosphere.
That conclusion needs to be stated more often and more forcefully, because it is the widespread demonization of “carbon”, and the resulting scare, that is being used to hobble our economies and raise our taxes — based on a false alarm.

P. Solar says:
December 8, 2012 at 12:06 am
However, the point you make about closing time of ice is fundamentally important.
The resolution indeed is important, but depends of the accumulation rate: the highest resolution is from two of the three Law Dome ice cores: some 1.5 m ice equivalent snow is accumulating there at the (near coast) summit. Its resolution is less than a decade. The drawback is that you don’t have many layers (thus years) back in time before you hit the rock beneath. That makes that the best resolution ice cores have a total time frame of only 150 years. The third Law Dome ice core was taken downslope and has a resolution of slightly over 20 years, but goes back some 1,000 years. Other cores (Vostok and Dome C) are far inland and have accumulation rates of a few mm per year, which makes that the resolution is far worse (app. 600 and 560 years), but you can look back over 420 and 800 kyears… Even so, any one-sided increase of 100 ppmv over a period of 160 years, as is now the case, would be detected even in the Vostok and Dome C records…

Ferdinand Engelbeen says:
December 8, 2012 at 3:05 pm
some 1.5 m ice equivalent snow is accumulating there at the (near coast) summit
Of course, that is per year, quite impressive…

D Böehm says:
December 8, 2012 at 2:39 pm
This conclusion is missing from most of Ferdinand’s Engelbeen’s comments
Indeed should repeat that more often, although many know my viewpoint… But for the new readers, I should do that again…

Bart

D Böehm says:
December 8, 2012 at 2:39 pm
“Ferdinand is very knowledgeable on the subject of CO2, and he is always patient with his explanations. “
Ferdinand is a very nice fellow, and he has his narrative down pat. But, it is just a narrative, and the temperature/CO2 relationship shows it has little connection with reality.

DDP

“The amount of greenhouse gases in the atmosphere reached a new record high in 2011, according to the World Meteorological Organization”
Really? I was under the crazy impression that CO2 levels had gone into four figure territory in planet Earth’s history on more than one occasion over the course of 4.5 billion years. I don’t think 400 years even qualifies as a mathematical percentage in that time period. ‘Record’ my arse*.
*also applies to Arctic sea ice extent ‘record’ low in a 33 year period.

From about 1940 through 1955, approximately 24 billion tons of carbon went straight from the exhaust pipes into the oceans and/or biosphere.
henry@ferdinand
what did I tell you. That looks to me like an awful lot more then 10 ppm’s CO2 (up or down ) per degree C (up or down) being dissolved in the oceans due to
(more) cold + CO2 + H2O => H3O+ (more) HCO3-
Obviously what is happening here:
if we follow hadcrut3&4 from 1925, it follows my sine wave, more or less,
http://blogs.24.com/henryp/2012/10/02/best-sine-wave-fit-for-the-drop-in-global-maximum-temperatures/
But my results show that from 1927-1950 we had been cooling, relatively speaking compared to 1950-1995. .
That would be the reason for the above mentioned sinc of CO2
Before 1927 the global temp. record is murky as I have yet to see a calibration certificate of a thermometer from before 1925. They did not calibrate after manufacture….
That leaves us with the conclusion that same sinc will happen again…..
From 2016 to 2035 the same thing will happen again. CO2 will stand still, or is already standing still or going up much slower and scientists are trying to hide this fact for fear of losing their jobs.
I note many “official” records only go to 2008.

prjindigo

Just to throw a “what if” out there…
What effect does available oxygen have and how has the available O2 varied along with the CO2 over the 700 million years that we can tweeze out this CO2 data from plants.
I ask because there is yet another thing that occurs on a regular basis with high energy solar radiation: Protons in the aurorae end up breaking up Ozone and making water. This would have some effect on the available O2 in the atmosphere.
I think that while this research AND the very nicely done explanations shed falling anvils on much of the IPCC’s “sly-hence” that we are a long long way from even beginning to understand and model the true systems’ interactions in the atmosphere.
——————-
I’d also like to point out that the simple act of TAKING ice core samples changes the CO2 concentration in the samples. Bubbles aren’t actually trapped in the ice, they simply exist there due to uniform pressure over a ‘statistically extra-significant distance of’ resistance to their escape. Once the core is out of the hole, it starts losing gasses due to depressurization.
I’ve not seen any articles or reference math for studies done to verify the accuracy in this circumstance. It leads me to believe that a much more complicated hole-boring system which takes samples AS it operates combined with a sister bore to determine the lamination will be needed to actually produce data on a scientific level.
It doesn’t matter how many people agree that you put the bones back together right on the dinosaur, if you can’t prove the bones are all from the same creature you haven’t produced a scientific result.

richardscourtney

D Böehm and Bart:
Science advances from mutually respectful disagreements.
Politics advances by obtaining consensus.
Here we are dealing with science.
Anybody who has followed the ‘CO2 debate’ knows that for many years Ferdinand and I have disputed what is and can be known about the cause(s) of the recent rise in atmospheric CO2 concentration. Simply, Ferdinand and I are clear protagonists on this issue.
I now write to support D Böehm when he says at December 8, 2012 at 2:39 pm

Ferdinand is very knowledgeable on the subject of CO2, and he is always patient with his explanations.

That is clearly true.
If anybody wants to dispute Ferdinand’s views of these issues – as I have often done over the years – then they should do it with proper respect. Ferdinand is an authority on the subject and deserves appropriate respect: he is not merely some warmunist troll.
Richard

Bart

richardscourtney says:
December 9, 2012 at 9:33 am
As I have stated, Ferdinand is a super nice fellow. I have rarely seen him rise to a level of anger even when confronted with severe provocation. But, an “authority”? That suggests a quality of even-handedness which I cannot say I have observed. Ferdinand is invested in a particular narrative explanation of how CO2 concentration comes about, and is too willing to accept evidence in favor of that narrative based on a threshold he does not accept for evidence running counter to that narrative.
Thus, the perfect match between the affinely mapped temperature integral and atmospheric CO2 is just a “coincidence”, even though it matches in every detail across the frequency spectrum, while the match between the affinely mapped cumulative emissions and atmospheric CO2, even though the match is in the low frequency regime only, is proof positive. The odds of the latter interpretation being correct versus the former are decidedly lopsided, to the point of absurdity.

HenryP says:
December 9, 2012 at 6:06 am
From about 1940 through 1955, approximately 24 billion tons of carbon went straight from the exhaust pipes into the oceans and/or biosphere.
24 billion tons of carbon = 24 GtC in 15 years or less than 2 GtC/year. While that is quite high for the CO2 levels of that time (20-24 ppmv above equilibrium, nowadays it is ~4 GtC/year for 100 ppmv above equilibrium) it is not uncommon for a brief period of time to see such a natural stall in CO2 increase. It may be a change in regional seawater temperature, caused by the switch of the PDO or other natural variations like an increased growth of vegetation (but that should be visible in the d13C record). Something similar can be seen during El Niño / La Niña switches, but on shorter time periods. The average amplitude of such switches is some 4 ppmv (~8 GtC) / °C
You may be right that we are heading to a cooler period, but that will only partly offset the rise in CO2 caused by human emissions…

David Middleton says:
December 9, 2012 at 6:38 am
David, the ice cores don’t reflect any oscillation shorter than the length of the enclosure time. But the question is if the current increase of CO2 is part of an oscillation…
If you look at the trend in CO2 levels, there is no sign of reduction in upspeed, to the contrary, the levels still increase in increase rate. Thus, in the past 160 years, we haven’t even reached 1/4th of the cycle, if it was an oscillation. That means that, if it is part of a cycle, the duration is at least over 640 years, long enough to show up in the Vostok (600 years enclosure time) and Dome C (560 years) records.
Moreover, we have an intermediate resolution ice core, which goes back some 60 kyear (Taylor Dome). That one shows some more detailed oscillations, but none with more amplitude than in the Vostok or Dome C ice cores. It doesn’t show any oscillation or one-sided uptick as the current one at any time over that period:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/antarctic_cores_150kyr.jpg
Further, the enclosure time is the most important part for establishing the resolution. Firn densification has far less influence: as long as there is exchange possible with open air, the air is exchanged at sufficient rate. Take e.g. the fast accumulating Law Dome cores: some 40 years until exclosure depth. The average air composition at closing depth (measured top-down in firn) is only 7 years older than the air of the atmosphere (measured at the South Pole).
Of course that is not a Gaussian distrubution and some of the air in the pores indeed is captured 40 years before, some is captured the same year, but both are small fractions of the total. The bulk is quite recent… Don’t forget that the air had 40 years the time to migrate up and down…
There is a theoretical model which shows how the contribution of different years is reflected in the Law Dome ice cores, confirmed by on the spot measurements (Etheridge e.a. 1992):
http://courses.washington.edu/proxies/GHG.pdf
See fig. 11, but the whole article is very interesting…