The AGW Myth of Back Radiation

Prior posts have shown intuitive examples that the theory of back radiation from greenhouse gases causing warming is fictitious, that NASA's Earth energy budget does not include back radiation at all (in stark contrast to the IPCC which shows it to be unidirectional and 95% of the solar input), and that at least 28 other analyses of the physics agree that back radiation can not cause additional increase in global temperature. The IPCC Earth energy budget was created by Kevin Trenberth, author of the climategate email stating "The fact is we can't account for the lack of warming at the moment and it is a travesty that we can't". Most likely, the reason the Trenberth/IPCC Earth energy budget can't account for the lack of warming is because warming from greenhouse gas back radiation doesn't exist.





Claes Johnson, professor of applied mathematics, KTH Royal Institute of Technology, Sweden, has a blog for those interested in the mathematics & physics of the atmosphere, and has a new post today which also finds the conventional greenhouse gas theory of back radiation or reradiation causing global warming to be fictitious:



AGW Myth of Reradiation:



AGW alarmism is  based on an idea of "reradiation" from an atmosphere with greenhouse gases, but the  physics of this phenomenon remains unclear. 

To test if  "reradiation" is a real phenomenon, we suggest the following experiment: On a night with moon-light so feeble that you can cannot read a newspaper, place yourself in front of a mirror letting the moonlight reflect from the newspaper to the mirror and back again, and check if you can now read. You will probably find that the paper is still unreadable as if the "reradiation" does not give more light.

To give this experiment theoretical support we consider the mathematics of wave propagation from a source at x=0 (Earth surface)  to a receiver at x=1 (atmospheric layer) described by the wave equation:

U_tt - U_xx = 0 for x in the interval (0,1)

with solution U(x,t) being a combination of waves traveling with velocity +1 and -1 along the x-axis, and with subindices indicating differentiation with respect to space x and time t. The boundary condition at the receiver may take the form

AU_t(1,t) + U_x(1,t) =0

with a positive coefficient A signifying:

• A = 0: soft reflection with U_x(1,t) = 0


• A large : hard reflection with U_t(1,t) = 0


• A = 1: no reflection: transparent absorption of all incoming waves at x = 1.

The basic energy balance is obtained by multiplying the wave equation by U_t and integrating 

with respect to x to give:

K_t + AU_t(1,t)^2 = -U_x(0,t)U_t(0,t) = Input Energy.

where K(t) is the energy of the wave over the interval (0,1). Assuming that K(t) stays constant so that energy is no accumulating, we have that 

Output Energy = A U_t(1,t)^2 = Input Energy.

In particular, with soft reflection with A = 0, the Input Energy is also zero. We learn that  it is not possible to "pump the system" by reflection at x = 1: If you change from transparency with A = 1 to reflection with A = 0, the system reacts by refusing to accept Input Energy.

Ergo: Reflection/reradiation cannot increase the insolation to the Earth surface. 

[added note: insolation refers to the radiation energy received on a given surface area in a given time.]