The Empty Postulate of CO2 Alarmism

CO2 climate alarmism is based on two basic postulates concerning the effect of doubled concentration of atmospheric CO2 (compared to pre-industrial time):

1. Radiative forcing of 4 W/m2
2. Global heating of 1 C from radiative forcing of 4 W/m2.

Let us see how are these postulates motivated: 1. is supposed to follow from measurements of spectra like the above from "Atmospheric Radiation", Goody (1989) observed for clear skies over the Gulf of Mexico, April 23, 1969. After Conrath et al (1970).

The idea is that the dip in the spectrum between 14 - 16 microns reflects the absorption and emission of atmospheric CO2, and that doubled CO2 will cause a certain widening of the dip which is translated to so called "radiative forcing" of 4 W/m2 according to Planck-Stefan-Boltzmann's radiation law (SB).

The so obtained radiative forcing of 4 W/m2 is then translated to 1 C of global heating by another application of SB which is the rationale of 2.

We see that both 1. and 2. originate from a spectrum which its translated first to radiative forcing and then to global heating with both steps relying on SB.

Is this a correct scientific mathematical argument? Is it so clear how to go from measured spectrum to estimated spectrum for doubled CO2 to radiative forcing to global warming?

No it is not at all clear, because SB describes radiation from a body into a surrounding of 0 K.

The Earth plus atmosphere radiates into a surrounding of about 3 K, and so SB may be applicable to the whole system, but SB does not in the same way describe the exchange of heat energy between the Earth surface and the atmosphere and this is where the radiative forcing is supposed to change global climate.

The net result is that the climate sensitivity of 1 C global warming from doubled CO2, cannot be viewed to describe any scientific reality, but is instead used simply as a definition or agreement. This is evidenced by the fact that all scientists are supposed to agree on the 1 C, from skeptics to alarmists. An they all do agree on the 1 C.

If you say that you the 1 C is not valid, you will meet the response that this it is not possible to say so, because all scientists agree on the 1 C and you cannot question a scientific agreement which is a definition. Or if you do, then you are silly.

To question that there are 100 centimeters on a meter will meet the same laughs as questioning the 1 C from doubled CO2.

But a definition has no scientific content and says nothing about reality. In particular it cannot be taken as point of departure for feedbacks, which is nevertheless done by both alarmists and skeptics.

Alarmists start with 1 C and jack it up to 3 C by positive feedback.

Skeptics start with 1 C and take it down to 0.5 C by negative feedback.

But a real skeptic would not start with 1 C, because it is not science. A real skeptic would seek to directly assess climate sensitivity, by measurements. Doing so indicates a climate sensitivity smaller than 0.5 C, thus so small that it cannot be identified.

The net result is that the basic postulate of climate alarmism of a climate sensitivity of 1 C is a definition empty of scientific content and as such of no value. Both skeptics and alarmists should be able to agree on this.

Also Judy Curry has now understood the emptiness of IPCC:

• The IPCC might have outlived its usefulness. Let’s see what the next assessment report comes up with. But we are getting diminishing returns from these assessments, and they take up an enormous amount of scientists’ time.