Saturday, May 25, 2013

New paper shows no correlation between CO2 and Greenland temperatures over past 7,200 years

A recent paper published in Quaternary Science Reviews shows no rational nor consistent relationship between CO2 levels and July air temperatures in West Greenland over the past 7,200 years. The authors also find "summer temperatures were 2-3°C warmer than present" between 6,000 and 4,000 years ago.

From the latest edition of the NIPCC Report:

Holocene histories of atmospheric CO2 concentration and West Greenland air temperature

Reference: Axford, Y., Losee, S., Briner, J.P., Francis, D.R., Langdon, P.G. and Walker, I.R. 2013. Holocene temperature history at the western Greenland Ice Sheet margin reconstructed from lake sediments. Quaternary Science Reviews 59: 87-100.

In a revealing study published in Quaternary Science Reviews, Axford et al. (2013) describe how they examined sedimentary records from five lakes (North, Fishtote, Loon, Iceboom and Pluto) near Jakobshavn Isbrae in central West Greenland, in order to investigate the timing and magnitude of major Holocene climate changes, with their primary objective being "to constrain the timing and magnitude of maximum warmth during the early to middle Holocene positive anomaly in summer insolation," which they did by analyzing various properties of sediment cores they extracted from the lakes in the summers of 2008 and 2009.

So what did they find? "Based upon chironomid assemblages at North Lake, and supported by records of organic sedimentation in all five study lakes," in the words of the six scientists, "we infer warmer-than-present temperatures by at least 7.1 ka [thousands of years before present] and Holocene maximum warmth between 6 and 4 ka," when they indicate that "the local ice sheet margin was at its most retracted Holocene position" and "summer temperatures were 2-3°C warmer than present during that time of minimum ice sheet extent."
A graphical representation of this temperature history is presented in the figure below, along with the concomitant history of earth's atmospheric CO2 concentration.

Figure 1. Reconstructed July air temperature anomalies in the vicinity of North Lake, inferred from chironomid data using three different calibration formulas (1. Weighted-averaging, orange line with triangle data points, 2. Weighted-averaging with tolerance downweighting, red line with triangle data points, 3. Weighted-averaging partial-least-squares, black line with circle data points), plus the mean of the three sets of results (green line, square data points), as adapted from Axford et al. (2013). Also shown is the concomitant history of earth's atmospheric CO2 concentration, as obtained from atmospheric measurements carried out at Mauna Loa, Hawaii (Boden et al., 1994), together with ice core data obtained at Law Dome (Etheridge et al., 1998) and Vostock (Keeling and Whorf, 1998), Antarctica.
As can be seen from the figure above, there is absolutely no rational relationship between the Holocene temperature history derived by Axford et al. and the air's COcontent. Over the first 1800 years of the record, for example, when the atmosphere's CO2 concentration rose by a sluggardly 10 ppm, Holocene temperatures rose, in the mean, by about 2.3°C. Then, over the following 2,400 years, when the air's CO2 content rose by about 20 ppm, mean summer air temperatures dropped by approximately 2.6°C. And over the next 1900 years, when the air's CO2 content rose by some 10 to 15 ppm, mean air temperature changed not at all. But over the final 300 or so years, when the atmospheric CO2 concentration rose by a whopping 125 ppm, summer air temperatures first declined by about 1.9°C and then rose by about 1.9°C, for essentially no net change. Clearly, the CO2 concentration of Earth's atmosphere would appear to have had no consistent impact on July air temperatures in the vicinity of North Lake, Greenland, over the past seven millennia.
Additional References
Boden, T.A., Kaiser, D.P., Sepanski, R.J. and Stoss, F.W. (Eds.). 1994. Trends '93: A Compendium of Data on Global Change. ORNL/CDIAC-65. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee.
Etheridge, D.M., Steele, L.P., Langenfelds, R.L, Francey, R.J., Barnola, J.-M. and Morgan, V.I. 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, Oak Ridge, Tenn., U.S.A.
Keeling, C.D. and Whorf, T.P. 1998. Atmospheric CO2 concentrations -- Mauna Loa Observatory, Hawaii, 1958-1997 (revised August 1998). NDP-001. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee.

7 comments:

  1. Lack of correlation with carbon dioxide is far from surprising when one understands the Uranus dilemma

    Consideration of the planet Uranus very clearly indicates that radiative models (and any type of "Energy Budget" similar to those produced by the IPCC) can never be used to explain observed temperatures on Uranus. We can deduce that there must be some other physical process which transfers some of the energy absorbed in the upper levels of the Uranus atmosphere from the meagre 3W/m^2 of Solar radiation down into its depths, and that same mechanism must "work" on all planets with significant atmospheres.

    Uranus is an unusual planet in that there is no evidence of any internal heat generation. Yet, as we read in this Wikipedia article, the temperature at the base of its (theoretical) troposphere is about 320K - quite a hot day on Earth. But it gets hotter still as we go further down in an atmosphere that is nearly 20,000Km in depth. Somewhere down there it is thought that there is indeed a solid core with about half the mass of Earth. The surface of that mini Earth is literally thousands of degrees. And of course there's no Solar radiation reaching anywhere near that depth.

    So how does the necessary energy get down there, or even as far as the 320K base of the troposphere? An explanation of this requires an understanding of the spontaneous process described in the Second Law of Thermodynamics, which is stated here as ...

    "The second law of thermodynamics: An isolated system, if not already in its state of thermodynamic equilibrium, spontaneously evolves towards it. Thermodynamic equilibrium has the greatest entropy amongst the states accessible to the system"

    Think about it, and I'll be happy to answer any questions - and explain what actually happens, not only on Uranus, Venus, Jupiter etc, but also on Earth.

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  2. http://www.sciencenews.org/view/generic/id/350253/description/News_in_Brief_Ice_loss_from_Greenlands_glaciers_may_level_off

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  3. insolation calculator:

    http://www.imcce.fr/Equipes/ASD/insola/earth/online/index.php

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  4. That study is very localized. It is not unusual for global CO2 levels to show no correlation to a local temperature - in fact, solar variations are a much larger driver of T variations in a CO2-stable world. Although I understand your desire to make climate scientists sound evil and stupid, I fail to see why this article should elicit so much excitement from you.

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    1. I see, well the fact is the only continuous high-resolution records extending back 7000+ years are the Greenland & Antarctic ice cores, both of which clearly show that temperature leads CO2 levels by 800+ years in accordance with Henry's Law. The cause does not follow the effect.

      I have no desire to "make climate scientists sound evil and stupid." I am a scientist myself and simply want the whole truth, and nothing but the truth, told.

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  5. It is disingenuous in the extreme to draw the conclusions you attempt to draw from Axford et al. I'm not a scientist of any description, but as I understand it the warmer temperatures in the Arctic during the mid-Holocene period were not global; they were restricted to the summer months in the northern hemisphere and they were caused by orbital forcing, whereas today's warming is largely caused by CO2.

    To say CO2 can't be a cause of global warming because temperatures were warmer 6000 years ago even though CO2 levels were low is a bit like saying Gas can't be a fire hazard because I started a fire with matches, not using any gas at all.

    Here is what Axford really believes, as opposed to the spurious interpretation you are giving to his work:

    "...the human impacts of climate change are present-day reality, not reserved for a distant future."

    "...ice cores recovered from Antarctica made it clear years ago that today's carbon dioxide levels far exceed anything Earth has seen for at least 800,000 years. We ignore such information at our own peril."

    "A favorite rhetorical strategy is to emphasize short-term fluctuations or local differences in climate or weather, while ignoring more meaningful long-term global trends."

    http://www.huffingtonpost.com/.../arctic-30_b_4325862.html

    (The paper you are citing is restricted access and requires a log-in; I'm citing from an open-access source so that readers of your blog can go there and see for themselves what Axford really thinks.)

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  6. "I'm not a scientist of any description, but as I understand it the warmer temperatures in the Arctic during the mid-Holocene period were not global; they were restricted to the summer months in the northern hemisphere and they were caused by orbital forcing, whereas today's warming is largely caused by CO2."

    False, the Holocene Climate Optimum was global and is seen in both Arctic and Antarctic ice cores.

    Today's warming is not "largely caused by CO2" as demonstrated in hundreds of posts:

    http://hockeyschtick.blogspot.com/2014/02/why-earths-climate-is-self-regulating.html

    http://hockeyschtick.blogspot.com/2014/03/why-ideal-gas-law-gravity-atmospheric.html

    ReplyDelete