Guest essay by Kyoji Kimoto
Dr. Robert D. Cess led the following Intercomparison Projects of GCMs for the IPCC
- 1989: Interpretation of Cloud-Climate Feedback as Produced by 14 Atmospheric General Circulation Models.
- 1990: Intercomparison and Interpretation of Climate Feedback Processes in 19 Atmospheric General Circulation Models.
- 1991: Interpretation of Snow-Climate Feedback as Produced by 17 General Circulation Models.
- 1993: Uncertainties in Carbon Dioxide Radiative Forcing in 15 Atmospheric General Circulation Models.
- 1996: Cloud feedback in 19 atmospheric general circulation models: An update.
His profile is here.
Soden & Held  shows climate sensitivity is 3K for 2xCO2 from the 14 GCM studies for the IPCC 4th Assessment Report (2007) as follows:
Climate sensitivity = no-feedback sensitivity (Planck response) x feedbacks
= 1.2K x 2.5 = 3K
Here, feedbacks are water vapor, ice albedo, lapse rate and cloud feedback.
In the AGW theory of the IPCC, the central assumption is that the Planck response is 1.2K. Cess [2, 3] obtained the Planck feedback parameter0 of -3.3(W/m2)/K utilizing eqn (1), giving the Planck response of 1.2K with the radiative forcing RF of 4W/m2 for 2xCO2 as follows:
Here, OLR (outgoing long wave radiation) = 233W/m2
Ts: the surface temperature of 288K
Coincidently, the Planck response of 1.2K by eqn (3) is in very good agreement with the Planck response of 1.2 – 1.3K obtained with one dimensional radiative convective equilibrium model (1DRCM) studies in the literature [4, 5, 6]. Therefore, the Cess method has been followed by many researchers, including the IPCC 1st Assessment Report (1990) and the 14 GCM studies for the IPCC 4th Assessment Report (2007).
The Cess method is the sole theoretical basis of the central assumption of the IPCC that the Planck response is 1.2K at present time [7, 8, 9], because the 1DRCM study is fudged due to its strong dependence on lapse rate used according to Hansen’s idea expressed in an interview with Spencer Weart held on 23 October, 2000 at NASA here..
The above derivation, however, is a mathematical error since the emissivityis not a constant enabling us to differentiate eqn (1) as shown by eqn (2). Cess admits his mathematical error in his reply to Kimoto’s mail on 23 August, 2016.
Schlesinger  proposed eqn (4) giving the Planck response of 1.2K, which is only a transformation of eqn (2) to disguise the Cess’s mathematical error as follows:
Planck response= 0.3K/ (W/m2) x 4 (W/m2) =1.2K
Read more: Leading Climate Scientist “Admits Mathematical Errors in The AGW Theory”! by P. Gosselin on 2 October 2016.
1. Soden, B.J. and Held, I.M., An assessment of climate feedbacks in coupled ocean-atmosphere models. J. Climate, 2006, 19, 3354-3360.
2. Cess, R.D., An appraisal of atmospheric feedback mechanisms employing zonal climatology, J. Atmospheric Sciences, 1976, 33, 1831-1843.
3. Cess, R.D., Potter, G.L., Blanchet, J.P., Boer, G.J., Ghan, S.J., Kiehl, J.T., Le Treut, H., Li, Z.X., Liang, X.Z., Mitchell, J.F.B., Morcrette, J.J., Randall, D.A., Riches, M.R., Roeckner, E., Schlese, U., Slingo, A., Taylor, K.E., Washington, W.M., Wetherald, R.T. and Yagai, I., Interpretation of cloud-climate feedback as produced by 14 atmospheric general circulation models, Science, 1989, 245, 513-516.
4. Manabe, S. and Wetherald, R.T., Thermal equilibrium of the atmosphere with a given distribution of relative humidity, J. Atmospheric Sciences, 1967, 24, 241-259.
5. Hansen, J., Johnson, D., Lacis, A., Lebedeff, S., Lee, P., Rind, D. and Russell, G., Climate impact of increasing atmospheric carbon dioxide, Science 1981, 213, 957-966.
6. Schlesinger, M.E., Equilibrium and transient climatic warming induced by increased atmospheric CO2, Climate Dynamics, 1986, 1, 35-51.
7. Wetherald, R.T. and Manabe, S., Cloud feedback processes in a general circulation model, J. Atmospheric Sciences, 1988, 45, 1397-1415.
8. Tsushima, Y., Manabe, S., Influence of cloud feedback on annual variation of global mean surface temperature, Journal of Geophysical Research, 2001, 106, 22,635-22,646.
9. Tsushima, Y., Abe-Ouchi, A. and Manabe, S., Radiative damping of annual variation in global mean temperature: comparison between observed and simulated feedbacks, Climate Dynamics, 2005, 24, 591-597.