Guest post by Peter Morcombe
Remember the case of “Silver Blaze”? Here Sherlock Holmes discusses it with a Scotland Yard detective:
Gregory: “Is there any other point to which you would wish to draw my attention?”
Holmes: ”To the curious incident of the dog in the night-time.”
Gregory: “The dog did nothing in the night-time.”
Holmes: “That was the curious incident.”
Why did the dogs fail to bark?
Just a few weeks ago I finally got around to looking at some papers relating to the EPICA “Dome C” ice cores. My interest stems from the idea that temperature changes are presumed to be magnified at high latitudes so it ought to be easier to measure “Global Warming near the poles. An earlier review of Greenland’s climate found an average temperature rise of 2.3 K since 1850, almost three times higher than the IPCC’s “Copenhagen Diagnosis” (0.8 K)
Ice cores provide an excellent record of past temperatures plus data on CO2, Methane, and volcanic dust. As the GISP ice cores go back only 130,000 years one might assume the climate was much warmer back then than it is today. This idea gets support from the EPICA ice cores that show the last Interglacial to be about 2 K warmer than the present one. This diagram below can be found at Wikipedia:
The separation between the Vostok and EPICA traces results from Vostok averaging ~6 K colder than EPICA. Let’s take a closer look at the EPICA record that extends almost 800,000 years into the past. In particular what do the EPICA researchers have to say about the relationship between CO2 and temperature? Here is Figure 2 from Luethi et al. (2008).
The abstract contains this statement:
“From previously published data1, 2, 3, 4, 5, 6, 7, 8 and the present work, we find that atmospheric carbon dioxide is strongly correlated with Antarctic temperature throughout eight glacial cycles….”
While this is clearly correct, the researchers do not claim that CO2 is the cause of the changing temperature.
Why did the dogs fail to bark?
The light blue plot shows the EPICA temperature file while the red plot is temperature calculated from the CO2 concentration [CO2] using the Arrhenius theory that CO2 is a primary “Greenhouse Gas”:
Temperature Anomaly = ΔT = A * log2 ([CO2]/280)……..Where A is a constant representing K/Doubling of [CO2].
The striking correlation over such a long period of time must mean something. So why is it not being trumpeted as a strong argument in favor of Arrhenius? The researchers could answer this question but they tend to “Lawyer Up”. For example, Thomas F. Stocker one of the researchers is fighting Steve McIntyre’s efforts to gain access to the deliberations the IPCC’s “Climate Scientists” (Working Group 1) who are working on the AR5 report due for publication in September. So let’s try to figure out what the problem is without their help.
Fig 2. uses the same data as Fig 1. but only the last 2,500 years are displayed. If “Climate Scientists” had used the EPICA data to vindicate Arrhenius they would need to explain why the Keeling Curve Hockey Stick (CO2 concentration) did not produce the expected 8 K temperature rise in the last 160 years. The actual “Global Warming” since 1850 was only 0.8 K, an order of magnitude less than than the EPICA data suggests.
To make the calculated data in Fig 1 (red plot) agree with the measured data (blue plot) I had to set the sensitivity constant to 16 K/Doubling of CO2, whereas to make the modern data fit (1850 to 2013) observations the sensitivity constant needs to be 1.6 K/Doubling. Who can believe that the sensitivity constant remained at 16 K/Doubling for 800,000 years and then suddenly changed to 1.6 K/Doubling in 1850?
There is an explanation that makes sense. The fluctuation of CO2 concentrations over the last 800,000 years were caused by fluctuations in ocean temperatures. The solubility of CO2 in sea water is a function of temperature. This hypothesis also accounts for the 500 year delay between rising temperature and rising CO2 concentration.
That still leaves the question of what caused the temperature changes associated with the last eight glacial cycles. Many people think that Milankovich cycles are responsible for the recent ice ages but the mathematics is a little shaky. Do you know anyone who can tell you when the next glaciation will start based on Milankovich’s theories?
It also leaves the question “What caused the 0.8 K global warming since 1850”? If CO2 lived up to Arrhenius’ expectations we would be in no doubt at all.
Peter Morcombe (gallopingcamel)
- Luethi, 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
- Jouzel, J., V. Masson-Delmotte, O. Cattani, G. Dreyfus, S. Falourd, G. Hoffmann, B. Minster, J. Nouet, J.M. Barnola, J. Chappellaz, H. Fischer, J.C. Gallet, S. Johnsen, M. Leuenberger, L. Loulergue, D. Luethi, H. Oerter, F. Parrenin, G. Raisbeck, D. Raynaud, A. Schilt, J. Schwander, E. Selmo, R. Souchez, R. Spahni, B. Stauffer, J.P. Steffensen, B. Stenni, T.F. Stocker, J.L. Tison, M. Werner, and E.W. Wolff (2007). Orbital and Millennial Antarctic Climate Variability over the Past 800,000 Years. Science, Vol. 317, No. 5839, pp.793-797, 10 August 2007.