End of the road

UPDATE: G&Trebuttal-2-6 is now posted. Pls use this one. Lots of small formatting changes to Figures and References. Should have all correction receive until 4/23@10 PM EDT. Adobe Acrobat version also available

Thanks to everyone who participated, the Gerlich and Tscheuschner rebuttal is pretty much finished (IEHO). It has been uploaded to Rabett Run Labs. The list of authors is incomplete, and some who are listed may want not to be listed, others who are not listed but contributed may want I. Eli tries to please. It would also be good to have affiliations for the authors, although I think not totally necessary.

After waiting a week time for further comments (and yes our Welsh mouse who bravely volunteered, for proof reading), I will send the paper to IJMP for publication. We will see what their response is (sure to be amusing:) and proceed accordingly. At the least we will place this in arXiv and perhaps at some other sites.

To give everyone an idea of the flavor of the thing, which has really changed for the better, here is the first couple of pages of the introduction.

Comment on “Falsification of the atmospheric CO2 greenhouse effects within the frame of physics”

By: E. Rabett, and the Bunnies (add or subtract your name here) Christopher M. Colose, Chris Ho-Stuart, Joel D. Shore, Arthur P. Smith, Jörg Zimmermann

Abstract: Gerhard Gerlich and Ralf D. Tscheuschner claim to have falsified the existence of an atmospheric greenhouse effect. Here, we show that their methods, logic, and conclusions are in error. Their most significant errors include trying to apply the Clausius statement of the second law of thermodynamics to only one side of a heat transfer process rather than the entire process, and systematically ignoring most non-radiative heat flows applicable to Earth’s surface and atmosphere. They claim that radiative heat transfer from a colder atmosphere to a warmer surface is forbidden, ignoring the larger transfer in the other direction which makes the complete process allowed. Further, by ignoring heat capacity and non-radiative heat flows they claim that radiative balance requires that the surface cool by 100 K or more at night, an obvious absurdity induced by an unphysical assumption. This comment concentrates on these two major points, while also making note of some of Gerlich and Tscheuschner’s other errors and misunderstandings.

1. Introduction

In a paper that recently appeared in the International Journal of Modern Physics Gerhard Gerlich and Ralf D. Tscheuschner (2009, hereafter GT09)claim to have falsified the existence of an atmospheric greenhouse effect. Here, we show that their methods, logic, and conclusions are in error. The authors describe “problems” that are not really problems. They are either not related to the greenhouse effect, or well known and understood minor issues such as the differences between the mechanisms by which a glass greenhouse warms and that by which the greenhouse effect leads to a warmer surface. GT09 do not come to grips with how the greenhouse effect emerges at levels of analysis typical of the modern state-of-the-art, such as from line by line calculations of atmospheric radiative transfer, global climate models (GCMs) or even on the level of advanced textbooks (Pierrehumbert 2009), but rather criticize simple, didactic models for not being complete. They make elementary mistakes in doing so. Their analysis of GCMs is limited to quoting from unrefereed sources and pronouncing on what they consider to be the requirements for a scientific theory. Further, they suggest that a good theory of radiative transfer would require use of inappropriate theoretical tools, such as Feynman diagrams for calculating vibrational emission and absorption probabilities in the atmosphere or magneto-hydrodynamics for analysis of flow in the lower atmosphere. In the first case quantum theory provides the theoretical background (for example, such textbooks as Hollas, 2004, Bernath 2005), and spectroscopic measurements the data base for line positions and cross-sections (Rothman, et al., 2008), in the second, conservation laws and discretized versions of the Navier Stokes equations for fluid flow in an unionized medium (Washington and Parkinson, 2005, Imskeller and von Storch, 2001 are book length treatments of these issues) allow us to successfully model the major circulation patterns in the atmosphere.

A recurring element in Gerlich and Tscheuschner (2009) is that others neglect the thermal conductivity of the atmosphere, presented in the introductory (“Problem background”) section covering the first 4 pages of the paper and also Section 3.8 as well as elsewhere in passing. However, they fail to place this in quantitative context. In fact the heat flows associated with conductivity are tiny, and hardly different from the value of zero they repeatedly criticize in the work of others. For example, for a typical lapse rate temperature gradient of 5 K/km, the resulting heat flow from atmospheric conductivity is about 1.5x10-4 W/m2, (according to Table 5 of GT09) far less than the 10’s or 100’s of W/m2 associated with other atmospheric heat flow processes (Trenberth, Fasulo and Kieho, 2009). Motionless air is a fairly good thermal insulator. GT09’s repeated reference to thermal conductivity is indicative of a lack of basic understanding of the relative scales of the important processes in Earth’s atmosphere.

The second section of GT09 (“The greenhouse effect hypothesis”) presents some information about atmospheric radiative processes, but in comparison to their detailed treatment of thermal conductivity in the first section, the only quantitative value here is an estimate of the (large) number of CO2 molecules an infrared photon might see in one wavelength of travel. This, they claim, requires a complex microscopic theory in contrast to the macroscopic thermodynamic properties associated with thermal conductivity (raised yet again). GT09 fail to acknowledge that spectroscopic properties of gases are themselves well-defined macroscopic properties that have been experimentally studied in extensive detail (Rothman, et al, 2008). The absorption and emission of any given wavelength from a given collection of gas molecules can be accurately quantified, and has been verified in both laboratory experiments (Flekl, et al., 2002 and measurements of radiation passing through Earth’s atmosphere (Bianchini, et al., 2008)

The next 18 pages of GT09 are devoted to showing that the atmospheric greenhouse effect relies on different physical processes than the warming in a glass greenhouse. Their short concluding paragraph (2.6) would have sufficed. Concisely, greenhouses work by restricting the outward flow of thermal energy to the surrounding atmosphere by convection, while the atmospheric greenhouse effect works by restricting the outward flow of thermal energy to space by radiation. In both cases restricting outward energy flow causes warming, so the analogy is not as irrelevant as GT09 claim.

The problems with these three sections are characteristic of the remainder of the paper. First, the authors’ lack of quantitative familiarity with the field they are criticizing, second their claims of complexity or invalidity, impossibility, and occasionally fraud regarding well-established quantitatively verified analyses of atmospheric processes, and third their extensive diversions on topics that do nothing to further their own argument or a reader’s understanding. In the remainder of GT09 we could find only two physically based criticisms of the greenhouse effect that actually require any substantive response.

The first of these claims in GT09 is the assertion that Clausius' statement of the second law of thermodynamics forbids transfer of heat from a colder atmosphere to a warmer surface. However, the second law requires consideration of all heat flows in a process, so one must simultaneously include the larger transfer of thermal energy from the surface to the atmosphere. Clausius’ statement also does not impede temperature changes resulting from a change in system properties such as adding glass to a greenhouse, or adding infrared-absorbing gases to the atmosphere. Any warming under such a change comes from the gradual build-up of energy and heat flows to a new steady-state, not the transfer of energy from cold to warm regions.

The second physically-based criticism that we could find in GT09 is in their model of a hypothetical Earth with a non-uniform temperature distribution, and their resulting arguments regarding average temperature and the magnitude of the greenhouse effect as a whole. Following Smith (2008) which was a response to an earlier version of GT09 (Gerlich and Tscheuschner, 2007) we find that Gerlich and Tscheuschner obtain an absurd result by using a very unphysical assumption, that each part of the planet's surface immediately cools or heats to reach an equilibrium with the locally impinging solar radiation, thereby neglecting the thermal inertia of the oceans, atmosphere and ground and all other heat transfer processes within the atmosphere and surface. Were this to be the case, all parts of the Earth would immediately drop to almost absolute zero at night, and the discrepancy between Earth’s observed average temperature and the average on this hypothetical Earth would be very large, over 100 K. It is shown that a uniform surface temperature model gives a more realistic bound on the greenhouse effect, the commonly quoted 33 K. This value is a lower bound on the magnitude of the greenhouse effect and even Gerlich and Tscheuschner’s result for their unphysical case obeys this bound.

Section 2 below disposes of GT09’s arguments about the second law of thermodynamics, principally laid out in their Section 3.9. In Section 3, simple models are introduced and then used to demonstrate Gerlich and Tscheuschner's aphysical picture of heat flow on a rotating planet (their Section 3.7). These two points clearly demonstrate that the radiative greenhouse effect significantly increases the surface temperature of the Earth, contrary to the conclusions of GT09.

The rest of GT09 essentially follows their initial pattern of poor physical intuition, wild claims, and irrelevant diversion. One example of their wild claims is the denigration of a simple net energy flow schematic for the earth such as is shown in Fig 1 below and Fig. 23 in GT09, because such diagrams (pp 322)

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