*Mr. Kyoji Kimoto has asked me to post the following essay, which tells us leading climate sensitivity scientist Dr. Robert Cess admits the IPCC assumptions are erroneous. (Note: Because WordPress didnâ€™t handle some of the scientific notation, I had to cut and paste parts of the text as images).*

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**Dr. RobertÂ D.Â Cess admits mathematical errors in the AGW theory of the IPCC**

by Kyoji Kimoto

Soden & Held [1] shows climate sensitivity is 3Â°K for 2xCO_{2} from the 14 GCM studies for the IPCC 4^{th} Assessment Report (2007) as follows:

Climate sensitivity = no-feedback sensitivity (Planck response) x feedbacks

= 1.2Â°K x 2.5 = 3Â°K

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 1.2Â°K. Cess [2, 3] obtained the Planck feedback parameter lambda_{0 }of -3.3(W/m^{2})/K utilizing eqn (1), giving the Planck response of 1.2K with the radiative forcing RF of 4W/m^{2} for 2xCO_{2} as follows:

Coincidently, the Planck response of 1.2Â°K by eqn (3) is in very good agreement with the Planck response of 1.2 â€“ 1.3Â°K 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 1^{st} Assessment Report (1990) and the 14 GCM studies for the IPCC 4^{th} Assessment Report (2007).

It is the sole theoretical basis of the central assumption of the IPCC that the Planck response is 1.2Â°K at present time [7, 8, 9], because the 1 DRCM study is fudged due to its strong dependence on lapse rate used according to Hansenâ€™s idea expressed in an interview with Spencer Weart held on 23 October, 2000 at NASA.

On 23 August, 2016, Dr. RobertÂ D.Â Cess gave me the following answer to my mail, admitting his mathematical errors in the derivation from eqn (1) to eqn (3). Dr. Cess was the leading climate scientist of Intercomparison Project of GCMs for the IPCC Assessment Reports. He wrote:

I will try this one more time, and then I will give up.Â A lot has happened since M&S (1964) and M&W (1967).Â In modern usage, the no-feedback sensitivity refers to holding all climate parameters fixed except surface temperature.Â It addresses the question: What would the sensitivity be if there were no interactive climate feedback mechanisms?.Â Simply stated, it is a hypothetical reference sensitivity.Â NO ONE HAS EVER CLAIMED THAT THE NO-FEEDBACK SENSITIVITY IS A TRUE INDICATION OF THE REAL SENSITIVITY.

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