In the modern climate doctrine 255 Kelvin is found everywhere, it’s the blackbody temperature of the Earth and the star number of climate physics. Whereas a house number is arbitrary.
255k is the calculated average temperature of Earth without an atmosphere (or at least without the greenhouse effect), given the total solar irradiance (TSI) at the top of the atmosphere (TOA) and the Earth albedo.
The avarage temperature of the Earth is 288k. Together with the blackbody temperature of the Earth, 255k, the difference is the greenhouse gases effect on the average temperature; i.e. an additional 33k. Hence, according to mainstream physics, the Earth would be a giant frozen snowball with an average temperature of -18 degrees Celsius, if not for the atmosphere.
The average temperature of Earth without an atmosphere is not a controversial number, quite the opposite. But in the dark secluded existence of climate scepticism nothing is sacred. As such, physicist Dr. Gerhard Kramm called 255k a house number in a controversy on the eminent climate blog The science of doom.
The average temperature of Earth is derived using the Stefan-Boltzmann law under the assumption that the effective temperature is met when incoming energy equals emitted energy by the heated Earth. But it is not used properly and the everywhere reproduced sloppiness is surprising and to some extent it diminishes the overall confidence in climate science.
First, the SB-law calculates the radiative heat transfer from one flat surface to another in vacuum. Nothing else. In the albedo of Earth the reflection of clouds and the atmosphere are included and the applied absorption is the solar irradiation of the Earth-surface, clouds and the atmosphere, i.e. the total Earth-system (resulting in an albedo of 0,3 and total absorption in the Earth-system of 0,7).
In other words, the SB-law is applied on a non-defined surface, i.e. the whole Earth-system. Hence, it is not applicable at all. In the same way, the result is compared with the average temperature of the Earth where we normally put thermometers, that is, slightly more than one meter above the ground (288k), and not the surface temperature (285k).
In this sense, there is no doubt that 255k is a house number.
Don’t take my word for it. It’s confirmed in the NASA energy budget below, despite the fact that NASA reproduces 255k everywhere just as everybody else.
The albedo of the Earth-surface is not 0,3 but rather 0,1, the emissivity is approximately 0,95 and the ratio of total solar irradiance absorbed by the surface is somewhere between 0,50-0,52. These are the numbers necessary to get the NASA energy budget result of average absorbed solar irradiance (163,3 above). Using the Earth-surface albedo and discarding the solar irradiance absorbed by the clouds and the atmosphere the average effective Earth-surface temperature is 240k or less. That is, even colder than the mainstream view, also implying an even greater greenhouse-effect (85+ k). That’s what the NASA energy budget really says.
Round One: 255k vs. house number 0 – 1.