Chapter 3 in Climate Change: The Facts is Nicola Scafetta on climate change and a number of natural cycles. This chapter is probably even more fun for nerds than the one about the gymnastic molecules of greenhouse gasses. I suppose you have to expect this kind of thing from Professor Scafetta because we are advised that he developed Diffusion Entropy Analysis, a method of statistical analysis to tell the difference between Levy Walk noises and Fractional (Fractal) Brownian Movement in complex systems. Obviously he could have been a rocket scientist too. You wont be tested on this but I put the links in so you don’t think that I made it up.
The point is that these techniques can detect cycles of different frequencies in a system and the cycles of temperature that Dr Scafetta is talking about are oscillations of 9.1, 10.5, 20, 60 115, 900-1000 and 2100-2500 years. These are cycles in solar activity, tidal effects of the Sun and Moon and I expected the various Milankovitch cycles. Actually he did not introduce Milankovitch cycles but there are many others involving the Sun, Moon and various planets.
There is a section on numerous studies that suggest low values for the forcing effect of CO2 and he opts for a number in the order of half those favoured by the IPPC. Other authors in the book opt for a tenth and some people of course insist that there is no forcing effect at all. Then he explains how the IPCC models have failed dismally in reconstructing the relationship between CO2 and the temperature in many of the cycles through the Holocene. There is a table demonstrating that with the record of the Greenland Ice Sheet over a period of 5-6000 years.
There is an important subsection on the hockey stick effect that brought Michael fifteen minutes of fame and excited the IPPC in 2001 (it later disappeared from the IPCC literature). Dr Scafetta explains that the first energy balance models and later the “sophisticated” CMIP5 models reconstruct the hockey stick pattern for the simple reason that they use the wrong number for CO2 forcing. There are still people holding out for the hockey stick effect because the models generate it but of course competent statistical analysis of the data led by Steve McIntyre and Ross McKitrick shows that it does not exist in the real world.
The Olympic level of mental gymnastics gets under way in the section on the decadal and multidecadal natural climate oscillations based on his spectral analysis of the global surface temperature. He finds that the spectral peaks are the same in the northern and southern hemispheres that suggests that they are coupled and have an astronomical origin. Effects due to the more immediate influence of the sun tend to be reversed in the two hemispheres due to the tilting of the Earth’s axis.
He reports a 60 year oscillation in several phenomena ranging from the Atlantic Multidecadal Oscillation (AMO) series to Indian monsoon records. An eleven year cycle of sunspot activity can be decomposed into three oscillations thus “a quasi-eleven-year main cycle modulated and bounded between the 9.93 year Jupiter-Saturn spring tidal-oscillation and the 11.86 year Jupiter orbital tidal-cycle, giving origin to two main modes at the ten to eleven-year and the eleven to twelve-year time scales.”
The bottom line is that he claims his analysis of cycles gives a very good match with the temperature record since 1860, very much better than the IPPC figures, and a projection through the 21st century that is less than 2C. Time will tell!
PS A reminder about the excellent book The Climate Caper by Garth Paltridge, very good on the historical background to the scare from “inside the whale” (the CSIRO) and a very clear account to the pitfalls of models, especially the one used by Garnaut to shape Australia’s climate policy. In case you are too busy to read it or too mean to buy it you can find an extended summary here.