The IPCC Trick: Climate Instability from Backradiation 3

IPCC climate alarmism claims a climate sensitivity of 3 C as the global warming resulting from a doubling of atmospheric CO2 from 0.028% to 0.056%.

The 3 C is obtained by various feedbacks from a no-feedback value of 1 C obtained by definition from Stefan-Boltzmann's radiation law assuming that doubled CO2 causes additional radiative forcing of 3-4 W/m2.

Doubled CO2 represents a 1% change of atmospheric radiation properties (dominated by water vapor), while 3 C represents 10 % of the total effect of the atmosphere increasing the Earth surface temp by 33 C from the Earth-atmosphere blackbody temperature of 255 K at an altitude

of 5 km to the observed 288 K at the surface.

The IPCC climate sensitivity of 3 C thus represents an instability of global climate with a 1% perturbation being capable of causing a 10 % change, thus with a large stability factor of size 10.

But global climate shows a remarkable stability over billions of years under large perturbations, and thus the large stability factor of IPCC does not seem to reflect any reality.

Instead a stability factor of size 1 or smaller is to be expected, from experience.

This was understood by IPCC when formulating the scientific basis of its climate alarmism, according to its political agenda of AGW. The 10 % change of 33 C therefore was transformed

into a 1% change the total temperature ~ 300 K, that is a transformation was performed from net change of temperature to gross temperature.

But this required a transformation from net radiative energy exchange between the atmosphere

and the Earth surface, to gross flow of energy, and to this end the concept of backradiation was invented. A net radiative energy flow between the Earth surface and atmosphere of size

30 W/m2 could then be connected to a gross radiative interchange of size 300 W/m2 with the atmosphere absorbing radiation from the surface and then "backradiating" the bulk of it to the Earth surface.

The above picture typical to IPCC presented by Satellite Applications for Geoscience Education, displays a gross backradition of 324 W/m2 from the atmosphere to the surface.

Equipped with the new concept of backradiation IPCC could now perform the transformation

from net to gross values and thus reduce the 10% perturbation of the net to a 1% perturbation

of the gross quantity. This is the IPCC Trick behind its climate alarmism with a climate sensitivity of 3 C.

In Computational Blackbody Radiation I argue that backradiation is unphysical with only net radiative energy transfer having a physical significance. I thus give evidence that IPCC's climate alarmism based on a climate sensitivity of 3 C, is scientific fiction.

An estimate of climate sensitivity using basic real physics and observations, presented in numerous blog posts and in Climate Thermodynamics, gives an upper bound of 0.3 C as a 1% effect (1% of 33 C) of a 1% cause (double CO2) in a a climate system which is not unstable.

This is 10 times smaller than the IPCC value of 3 C and does not motivate any reduction of CO2 emission into the atmosphere.