onsdag 29 februari 2012

The thermodynamics of Fred Singer

Fred Singer attacks greenhouse effect deniers in a recent article entitled "Climate Deniers are giving us skeptics a bad name". The main argument addressing the deniers read:

"Now let me turn to the deniers.  One of their favorite arguments is that the greenhouse effect does not exist at all because it violates the Second Law of Thermodynamics -- i.e., one cannot transfer energy from a cold atmosphere to a warmer surface.  It is surprising that this simplistic argument is used by physicists, and even by professors who teach thermodynamics.  One can show them data of downwelling infrared radiation from CO2, water vapor, and clouds, which clearly impinge on the surface.  But their minds are closed to any such evidence."

I'm not sure if I belong to the category of "deniers" that Singer refers to although I do plead guilty to having introduced the somewhat bad name "lukewarmer" to the category of "skeptics" that Singer belongs to. One of the favourite twistings of the lukewarmers is that they present neither the greenhouse effect nor the second law of thermodynamics in a way that allows for a serious scientific discussion. I shall also admit that many skeptics fail to notice these twistings and often fall into futile discussions about the existence of "back-radiation". 

First of all, as I recollect the second law of thermodynamics it reads something like this:

The spontaneous tendency of a thermodynamic system to reach equilibrium can only be reversed if at the same time some organized energy is transformed into heat.

How does this apply to the greenhouse effect? If people check the sources or read the relevant articles of for example Roy Spencer, which I reckommend them to do, it becomes clear that the greenhouse gases alone are responsible for turning an isothermal atmosphere, which by definition is in equilibrium, to an atmosphere with a very steep temperature gradient, which by definition is not in equilibrium. The same happens in your refrigerator: turn the electricity off and the beer gets isothermal with the kitchen. What is the difference? The refrigerator uses electricity, which is a form of organized energy.

Fred Singer then, of course, twists things again when he equalizes the greenhouse effect with the existence of "back-radiation". The question is now, is Singer serious?

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