Rehashed Myths

David Evans and his rerouting negative feedback.

The climate contrarian longingly awaits for a new theory for climate change. The greenhouse effect has been rejected at every level from denying CO2 concentrations are growing because of human emissions, to denying there is a greenhouse effect, or accepting that there is a GHE but it is very small. The contrarian will happily believe all of these. Evans claims yes there is a greenhouse effect but it is very small and is preparing for his ultimate blog to falsely claim the climate sensitivity to doubling CO2 is less than 1C and when you include feedbacks it will be even smaller. This will be readily accepted by the gullible. His analogy he presents is flawed however and would in fact lead to the opposite...... ..runaway temperatures.

How is Evans going to do this?

He has prepared ground by inventing new terminology for the Planck feedback effect. He will be able to simplify this and then count it twice to introduce extra negative feedbacks.

A strategy that he uses is to say some fact, that he realizes the typical climate contrarian may be unaware of, and pretend it is something new. First, however, let us look at the Planck effect.

The Planck feedback effect.

When greenhouse gases are increased energy radiated to space via longwave radiation,LWR, is reduced for certain wavelengths. The temperature at the surface increases and radiation to space from other wavelengths are increased from the surface and gases in the atmosphere. (You can see the effect of a distorted frequency spectrum of LWR to space as viewed from satellites). Eventually equilibrium is achieved whereby the radiation coming into the atmosphere and leaving the atmosphere are once again balanced. On average this will mean that radiation to space occurs at a higher altitude. The only way equilibrium can be achieved is by higher temperatures being reached. The Planck effect stops further increases in temperature. It must exist otherwise temperatures would runaway and we would “cook”.

Now if this information is given to the typical contrarian it will be rejected. But if Evans pretends he has found something new, when he says radiation is rerouted, it will be readily accepted in the belief that a new negative feedback has been found.

http://joannenova.com.au/2015/10/new-science-7-rerouting-feedback-in-climate-models/

I expect we will see Evans making further use of this to achieve his unrealistic lower climate sensitivity in future blogs that is not only contrary to climate models but also paleoclimate evidence.

Evans will effectively use the Planck effect via the Stefan-Boltzmann equation and use it AGAIN when he introduces this as a negative feedback on top of this Planck feedback effect. He will count the same effect twice just under different names.

His electrical analogy using currents and resistors  however is fatally flawed.

According to this analogy if one of the “pipe” lines is blocked the current (outgoing heat) would be reduced and never reach equilibrium (meaning reach its previous value). The outgoing long wave radiation would be less than the previous outgoing LWR that was equal to the incoming solar radiation. We would cook. This is regardless of any other parallel resistors and should be obvious to those with a basic understanding of elementary “resistors in parallel” theory.

Again nothing new.

Not realizing his rerouting idea is just a flawed look at the Planck response he considers this in his next blog.

http://joannenova.com.au/2015/10/new-science-8-applying-the-stefan-boltzmann-law-to-earth/

“There is no single layer that radiates to space, instead emissions come from many different heights, depending on the wavelength. We could average the emissions into “one layer”, but doing that would lose detail that matters when computing sensitivity to increasing CO2.”

This is another example of pretending to say something new. However ironically, yet again, it is Evans who fails to take account of this and not the climate models.

After a rather trivial point including the emissivity of the Earth to LWR to be slightly less than 1 he decides to talk about an effective radiating temperature and a real Earth.

“While the numerical difference between T_R and T_e is insignificant, here we are concerned with OLR from the real Earth so it is more natural to use radiating temperature (and technically incorrect to use T_e, at least conceptually).”

Yet again it is Evans who fails to deal with a real Earth.

When Evans calculates the “Stefan-Boltzmann’s sensitivity” and claims it is different than Planck feedback it is different because it is he who has failed to take account of his two observations regarding single layers and the real world.

He has used a zero dimensional model for a back of the envelope calculation, (good enough for use in teaching elementary introductory aspects of climate science), assuming no changes in altitude for different wavelengths or changes across the surface of the Earth. He has also assumed a change in Te (or whatever he would like to call it) instead of a change in temperature at the surface for a given feedback response in W/m2 to achieve equilibrium. With a forcing due to greenhouse gases there is no change in Te when equilibrium is reached but there is a change in Ts.

Evans has calculated the simple rate of change of effective radiating temperature with respect to the outgoing radiation at the top of the atmosphere instead of the more complex but meaningful rate of change of surface temperature with respect to the outgoing radiation at the top of the atmosphere and hence arrives at the simplified Te/4R (or Tr/4R) approximation for the feedback free climate sensitivity parameter.