måndag 31 januari 2011

Greenhouse Effect Debate

Judy Curry has opened a debate on the book Slaying the Sky Dragon: Death of the Greenhouse Gas Theory, focussing on my two chapters
I look forward to a hopefully constructive lively discussion. Science does not thrive under dead
silence. In particular, I hope that Spencer, Lord Monckton, Lindzen and other leading skeptics will give the debate some attention.

My perspective is mathematical including both mathematical modeling and computation. I believe that physics must be expressed in mathematical terms, typically as differential equations, to have a precise meaning, and that understanding physics basically boils down to understanding mathematical models of different physical real phenomena, in the spirit of Dijkstra.

I give different presentations of the underlying idea of computation of finite precision in posts on thermodynamics, blackbody radiation, greenhouse effect and climate on this blog and in My Book of Knols and under "books" on my home page.

I repeat that I do not say "that there is no greenhouse effect" since the "greenhouse effect" is not well described in the literature. So anyone preparing to accuse me of "denying the greenhouse effect" should also prepare to tell me what sort of "greenhouse effect" I am supposed to deny. "Greenhouse effect denier" has the same value as "climate change denier".

What I am saying is that there is no backradiation, because that would correspond to an unstable physical phenomenon, as unstable and unphysical as "backdiffusion" or "backconduction".

What I am saying is that radiation alone without thermodynamics cannot tell anything meaningful about climate. A no-feedback sensitivity of + 1 C is just a formality or definition without any connection to reality, as non-informative as the statement that there are 100 centimeters on a meter, with its nature of definition signified by the message that it is "unassailable". Anything "unassailable" is a definition and a definition carries no information about reality. This is important to understand for both CO2 alarmists and skeptics, since CO2 alarmism starts with the basic postulate of a no-feedback climate sensitivity of + 1 C, which is then jacked up to + 3 C by positive feedback. Without the + 1 to start from, CO2 alarmism has to start feedbacks from 0, which is a completely open game with not even the sign being known.

Review of the debate after 83 comments Jan 31:
  • None of the big skeptics has had anything to say. Only Judy Curry who agrees that something is wrong with the Kiehl-Trenberth energy budget, but does not want to tell what.
  • Of course Monckton and Spencer do not want to answer any of my questions, or Lindzen...
  • If you are a skeptic then you pose questions, and of course do not answer any, just like a professional journalist or Freudian therapist. But scientists need to answer questions.
  • Mostly confusing remarks as if my message has not be absorbed at all. Absorbitivity = 0.
  • The "greenhouse effect" is strong and healthy science, although the equations are missing.
  • Judy Curry clarifies and says that the KT budget with backradiation is basically correct.
Summary of my position Febr 1:
  1. Radiative heat transfer is carried by electromagnetic waves described by Maxwell's equations. The starting point of a scientific discussion of radiation should better start with Maxwell's equations than with some simplistic ad hoc model like the ones typically referred to in climate science with ad hoc invented "back radiation" of heat energy. If there is anything like "backradiation" it must be possible to find it in Maxwell's wave equations. In my analysis I use a version of Maxwell's wave equations and show that there is no backradiation, because that would correspond to an unstable phenomenon and unstable physics does not persist over time.
  2. Climate results from thermodynamics with radiative forcing, and radiation alone cannot tell anything of real significance, such as the effect of changing the atmospheric radiative properties a little: It is not clear if more clouds orwater vapour will cause global cooling or warming, or the effect of a small change of CO2. Climate CO2 alarmism is based on a postulate of a climate sensitivity of + 1 C which is a formality without known real significance.
  3. I welcome specific comments on these two points.

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