The climate models sensitivity to carbon is overrated

Written by Professor Albert Parker

Comment to Otto, A., Otto, F.E.L., Boucher, O., Church, J., Hegerl, G., Forster, P.M., Gillett, N.P., (…), Allen, M.R., Energy budget constraints on climate response, Nature Geoscience 2013 6 (6):415-416:

The climate models sensitivity to carbon is overrated

Albert Parker


Comparison of reconstructed global land and sea temperature (for example GISS [1]) and anthropogenic carbon dioxide time histories (for example CDIAC [2]) over the last century show a very different sensitivity of temperatures to anthropogenic carbon dioxide emissions than what is claimed by Otto, A., Otto, F.E.L., Boucher, O., Church, J., Hegerl, G., Forster, P.M., Gillett, N.P., (…), Allen, M.R. in their paper Energy budget constraints on climate response, Nature Geoscience 2013 6 (6):415-416.

The reason why climate models are failing so badly so quickly is not because of the “variability” in the climate, but because of the overrated effect of anthropogenic carbon dioxide emissions and neglected natural oscillations.

Figure 1 presents the non-dimensional global temperatures as reconstructed by GISS and the non-dimensional carbon emission as reconstructed by CDIAC vs. time 1910 to present. While carbon emissions are growing almost exponentially, the temperature has a much more complex behaviour where two natural oscillations of about 60 years are clearly superimposed to a longer term trend that may be natural and/or carbon driven. The upwards phases 1910 to 1940 and 1970 to 2000 are followed by the downward phases 1940 to 1970 and 2000 to the present (and very likely to 2030). As pointed out in the recent works [3-7], the climate sensitivity is overrated when correlating the temperature and carbon dioxide emission behaviour over the time window 1970 to 2000.

Worthy of mention, the GISS reconstruction has a tendency to underestimate the temperatures in the past and overestimate the present temperatures because of “contamination” and “upwards biasing” effects [8]. If we compare the temperatures accurately measured in some selected location with the GISS values, for example Ballarat, Victoria, Australia, a small city in a less developed area 114 km away from the huge urban heat island of Melbourne, Victoria, Australia, or Alice Spring, Northern Territory, Australia, where the only long term nearby station is 1497 km km apart, the “contamination” and “upwards biasing” error is significant [8] and the temperature trend cleared of this effect is mostly oscillating.

The analysis of the GISS data uncorrected or corrected evidences a pattern made of natural oscillations of the climate as long since known, and with a significant reduction of the magnitude of the anthropogenic forcing through the changed composition of the atmosphere.


  1. National Aeronautics and Space Administration Goddard Institute for Space Studies (2013), GISS Surface Temperature Analysis (GISTEMP).

  2. CDIAC (2013), Global Fossil-Fuel Carbon Emissions.

  3. A. Parker, “The “present global warming hiatus” is part of a quasi-60 years oscillation in the worldwide average temperatures in the downwards phase”, ESAIJ, accepted paper, in press (2013).

  4. Scafetta, N., “Discussion on climate oscillations: CMIP5 general circulation models versus a semi-empirical harmonic model based on astronomical cycles”, Earth-Science Reviews 126:321-357 (2013).

  5. Scafetta N., “Solar and planetary oscillation control on climate change: hind-cast, forecast and a comparison with the CMIP5 GCMs”, Energy & Environment 24(3-4):455–496 (2013).

  6. Scafetta N., “Does the Sun work as a nuclear fusion amplifier of planetary tidal forcing?”, paper presented At the Space Climate Symposium-5 in Oulu, Finland. June 15-19, 2013.


  8. A. Parker, “WHY GLOBAL WARMING WENT MISSING SINCE THE YEAR 2000”, NLENG, accepted paper, in press (2013). 

GISS versus CDIAC mismatch


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Comments (1)

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    Visiting Physicist


    Once again PSI goes along the path of assuming (like the IPCC) that planetary surface temperatures can be determined by radiation levels received. The Venus surface receives about 10% of what Earth’s surface receives from the Sun, but the Venus surface is hundreds of degrees hotter. When are you all going to dismiss these concepts? When are you going to realise that the only effect of carbon dioxide is to cool by something of the order of 0.002 degree. It has no warming effect whatsoever. It has no “insulating effect” whatsoever. Engineers would never suggest using radiating gases like water vapour or carbon dioxide in the space between double glazed windows. They use dry air or, better still, non-radiating argon.

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