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The greenhouse effect and the 2nd law of thermodynamics

What the science says...

Select a level... Basic Intermediate

The 2nd law of thermodynamics is consistent with the greenhouse effect which is directly observed.

Climate Myth...

2nd law of thermodynamics contradicts greenhouse theory

 

"The atmospheric greenhouse effect, an idea that many authors trace back to the traditional works of Fourier 1824, Tyndall 1861, and Arrhenius 1896, and which is still supported in global climatology, essentially describes a fictitious mechanism, in which a planetary atmosphere acts as a heat pump driven by an environment that is radiatively interacting with but radiatively equilibrated to the atmospheric system. According to the second law of thermodynamics such a planetary machine can never exist." (Gerhard Gerlich)

 

Skeptics sometimes claim that the explanation for global warming contradicts the second law of thermodynamics. But does it? To answer that, first, we need to know how global warming works. Then, we need to know what the second law of thermodynamics is, and how it applies to global warming. Global warming, in a nutshell, works like this:

The sun warms the Earth. The Earth and its atmosphere radiate heat away into space. They radiate most of the heat that is received from the sun, so the average temperature of the Earth stays more or less constant. Greenhouse gases trap some of the escaping heat closer to the Earth's surface, making it harder for it to shed that heat, so the Earth warms up in order to radiate the heat more effectively. So the greenhouse gases make the Earth warmer - like a blanket conserving body heat - and voila, you have global warming. See What is Global Warming and the Greenhouse Effect for a more detailed explanation.

The second law of thermodynamics has been stated in many ways. For us, Rudolf Clausius said it best:

"Heat generally cannot flow spontaneously from a material at lower temperature to a material at higher temperature."

So if you put something hot next to something cold, the hot thing won't get hotter, and the cold thing won't get colder. That's so obvious that it hardly needs a scientist to say it, we know this from our daily lives. If you put an ice-cube into your drink, the drink doesn't boil!

The skeptic tells us that, because the air, including the greenhouse gasses, is cooler than the surface of the Earth, it cannot warm the Earth. If it did, they say, that means heat would have to flow from cold to hot, in apparent violation of the second law of thermodynamics.

So have climate scientists made an elementary mistake? Of course not! The skeptic is ignoring the fact that the Earth is being warmed by the sun, which makes all the difference.

To see why, consider that blanket that keeps you warm. If your skin feels cold, wrapping yourself in a blanket can make you warmer. Why? Because your body is generating heat, and that heat is escaping from your body into the environment. When you wrap yourself in a blanket, the loss of heat is reduced, some is retained at the surface of your body, and you warm up. You get warmer because the heat that your body is generating cannot escape as fast as before.

If you put the blanket on a tailors dummy, which does not generate heat, it will have no effect. The dummy will not spontaneously get warmer. That's obvious too!

Is using a blanket an accurate model for global warming by greenhouse gases? Certainly there are differences in how the heat is created and lost, and our body can produce varying amounts of heat, unlike the near-constant heat we receive from the sun. But as far as the second law of thermodynamics goes, where we are only talking about the flow of heat, the comparison is good. The second law says nothing about how the heat is produced, only about how it flows between things.

To summarise: Heat from the sun warms the Earth, as heat from your body keeps you warm. The Earth loses heat to space, and your body loses heat to the environment. Greenhouse gases slow down the rate of heat-loss from the surface of the Earth, like a blanket that slows down the rate at which your body loses heat. The result is the same in both cases, the surface of the Earth, or of your body, gets warmer.

So global warming does not violate the second law of thermodynamics. And if someone tells you otherwise, just remember that you're a warm human being, and certainly nobody's dummy.

Basic rebuttal written by Tony Wildish


Update July 2015:

Here is the relevant lecture-video from Denial101x - Making Sense of Climate Science Denial

 


Update October 2017:

Here is a walk-through explanation of the Greenhouse Effect for bunnies, by none other than Eli, over at Rabbit Run.

Last updated on 7 October 2017 by skeptickev. View Archives

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Further reading

  • Most textbooks on climate or atmospheric physics describe the greenhouse effect, and you can easily find these in a university library. Some examples include:
  • The Greenhouse Effect, part of a module on "Cycles of the Earth and Atmosphere" provided for teachers by the University Corporation for Atmospheric Research (UCAR).
  • What is the greenhouse effect?, part of a FAQ provided by the European Environment Agency.

References

Comments

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Comments 1151 to 1175 out of 1393:

  1. TOP - if the article doesnt convince of the nonsense in this paper, try the more exhaustive treatment at science of doom. Quoting G&T is crank-alert material. Like any science, if your theoretical prediction is at odds with reality, then you need to fix the theory.
  2. @1150,355 muoncounter I looked at a particular reference you cited, W. M. Connelly, June 2000 in which Connelly takes exception to Woods (1909) statements in the 2nd to the last paragraph while disregarding the implications experiment with the rock salt greenhouse. G&T performed the same experiment and got the same results as Wood. Note: Both G&T even refined the experiment so that the two "greenhouses" achieved much closer agreement in temperature by blocking IR from entering the rock salt greenhouse. Since Connelly was taking exception to the 2nd to the last paragraph and not the results or implications of the experiment it isn't much of a rebuttal. The results of the experiment which Connelly seems to be in agreement with is that the "greenhouse" effect has nothing to do with radiation being trapped on it's way back to space which is born out by the fact the plate glass is perfectly opaque to IR while rock salt is perfectly transparent to IR.
    Third, in contradiction to his assertion about "the very low radiating power of a gas", the troposphere is largely opaque to infra-red radiation, which is why convection is so important in moving heat up from the surface. Only in the higher (colder) atmosphere where there is less water vapour is the atmosphere simultaneously somewhat, but not totally, transparent to infra-red and thus permits radiation to play a part. [bolding is mine for emphasis]
    The "greenhouse" effect has everything to do with the prevention of convection from cooling the surfaces on which radiation impinges. In other words the AGW crowd in incorrect in applying the term "greenhouse effect" to anything to do with trapping radiation. That pretty much renders useless much of the discussion in this thread having to do with radiation. And as an added bonus Connelly attributes the opaqueness of the atmosphere to IR to water vapor, not CO2 I will also add that if anything was done incorrectly in the experiments of Wood, G and T, it was in not also measuring the pressure and hence the enthalpy change inside the greenhouse. And I have from time to time done an experiment of my own that contradicts Connelly's assertion that the troposphere is opaque to infrared. I simply went outside with an non-contact IR thermometer and pointed it at the sky on a clear day and a cloudy day. On a clear day, even with sun at noon you get something on the order of -55F while on a cloudy day you get something on the order of 32F. In fact today, while it is lightly raining the "sky temperature" is 27F. So on a clear day I can easily measure the temperature of the stratosphere from the ground with an IR thermometer and on a cloudy day I can measure the temperature of the bottom of the clouds. That is hardly a troposphere opaque to IR. So you have to deal with two experimental pieces of evidence that show that Connelly is right and in agreement with both Wood and G&T, that is, convection or the lack thereof, not radiation that is responsible for controlling the temperature in the atmosphere. G&T, Connolly and Wood are in agreement that "greenhouse effect" is a misnomer and should not be used in the context of global warming. Greenhouses warm because convection is prevented and not because IR radiation is blocked. There is no "greenhouse" effect in the atmosphere. This is not denialist, it is experiment.
  3. 105, TOP, The Wood experiment is invalid and you misunderstand Connelly. SkS will have a post on it soon, but in a nutshell the problem with the experiment (actually, there are a few) is that the model is not an accurate representation of the atmosphere exactly because convection and other mechanisms in the experiment are allowed to heat the glass and rock salt plates, which removes any temperature gradient between the heated "surface" and the covering "top of atmosphere". Basically, the glass and rock salt both radiate at the same temperature as the inside of the box because they've been allowed to warm by means other than radiation. The atmosphere does not work this way, and the model represented by the experiment therefore does not accurately represent that actions of the atmosphere. More importantly, the experiment is therefore not properly controlled to be certain that the effect being measured is only that of infrared radiation versus other means. It basically tests if convection occurs in a closed box -- not a very useful thing to know. To perform the experiment correctly the transfer of radiation by means other than radiation must be inhibited (as it is in the atmosphere, where convection is not efficient or active enough to transfer that much energy to the point in the atmosphere where heat radiates away). In the case of the more correct experiment, the rock-salt plate will remain cool and IR will be emitted through it according to the temperature of the "surface" which is heated only by the incoming short-wave radiation, while the surface within the other box will heat further until an equilibrium is reached where the "surface" warms further than the rock-salt box and the glass plate itself has warmed — purely through absorbing IR — and is emitting infrared both up and down. On your own experiment... you are not measuring the temperature of the stratosphere. The air around you is densely packed with CO2 and H2O which are radiating in the infrared and contaminating your experiment. You are merely measuring the emissions of the atmosphere immediately above you.
  4. TOP: Even contrarian scientist Roy Spencer points out that the physical basis for global warming (outgoing longwave infrared radiation being trapped by the atmosphere) is correct. Both surface-measured backradiaton from the atmosphere and satellite-measured reduction in radiation at greenhouse gas-related frequesncies are empirically documented in the literature. The simple fact is that physical theory, experiment, and empirical evidence show that, however misnamed, greenhouse gases in the atmosphere trap outgoing heat and cause warming. Also, did you not actually read the quote you cited? It states, right there that "the troposphere is largely opaque to infra-red radiation". How could that be, I wonder?
  5. @1150,355 muoncounter I'm talking about those responding to the original post. In fact I wonder if the OP actually read G&T. As for comment #2, that post says G&T is completely wrong. That is a pretty broad statement. It means that the experiment that they did to show what the greenhouse effect is was wrong. And it means that in your quote of Connelly, he was wrong. The posts seem to wander away from dealing with G&T ad nauseum.
  6. @1153 Sphaerica I'm glad you agree with G&T. The term "greenhouse" is a misnomer when talking about the atmosphere. G&T propose using the term "atmosphere effect".
    Fleagle and Businger (1963) [125] devoted a section of their text to the point, and suggested that radiation trapping by the Earth’s atmosphere should be called ‘atmosphere effect’ to discourage use of the misnomer. Munn (1966) [126] reiterated that the analogy between ‘atmosphere’ and ‘greenhouse’ effect ‘is not correct because a major factor in greenhouse climate is the protection the glass gives against turbulent heat losses’.[G&T quoting Lee, 1973]"Falsification Of The Atmospheric CO2 Greenhouse Effects Within The Frame Of Physics", Gerlich and Tscheuschner, 2009, p37
    Further, the purpose of the Wood experiment was to determine whether it was radiation or convection that caused a greenhouse to warm. The results of the experiment were that a)it was convection, or the lack thereof that caused the greenhouse to warm and b)the heating of the greenhouse was influenced by IR from the sun causing the rock salt greenhouse to be warmer since rock salt allowed more IR radiation into the greenhouse.
    When exposed to sunlight the temperature rose gradually to 65◦C, the enclosure covered with the salt plate keeping a little ahead of the other, owing to the fact that it transmitted the longer waves from the Sun, which were stopped by the glass. In order to eliminate this action the sunlight was first passed through a glass plate.[bolding mine][G&T quoting Wood, 1909]"Falsification Of The Atmospheric CO2 Greenhouse Effects Within The Frame Of Physics", Gerlich and Tscheuschner, 2009, p33
    Indeed, if the atmosphere were opaque to IR (longer wavelengths) we would expect global cooling based on this experiment.
    Response: [JH] There is no need for you to use a small font size for citations. If text is so tiny to be unreadable, it has no value.
  7. @1154 Composer99 My experiment with the IR thermometer showed that the troposphere is not opaque to IR. Someone mentioned that I was measuring the temperature of the air around me with the IR thermometer. That is incorrect, I get essentially the same readings on a clear day whether the outside temperature is 90F or 20F. When clouds intervene the sky temperature goes up because the bottom of the clouds is lower and the clouds have to be at a temperature above freezing to exist. So, Connelly was wrong to say the troposphere is opaque to IR. G&T also talk about this in their discussion about how there can be frost on the ground when the air temperature is above freezing.
  8. I can't belive that the meme "greenhoue effect is a minomer" keeps poppping up. It really tells nothing about the science and is a distraction that no one nedd, not even the sceptics/deniers. If Arrhenius (who probably was the first to use this analogy) knew, I'm sure he would not use it. And who's going to tell Tyndall of the new findings that "That is hardly a troposphere opaque to IR"? Luckly, we have comforting breking news: "Greenhouses warm because convection is prevented and not because IR radiation is blocked." Who could immagine that! Sorry for the sarcasm, TOP. But really the knowledge of the physics of the atmosphere and of radiation is way beyond that. Maybe you're right that it's not denialism but sure enough it's not "experiment" either.
  9. TOP, the term "greenhouse effect" is perfectly legitimate and useful for its intended use as a teaching and communication analogy for the high level mechanism: More energy comes in than goes out. You are obsessing about something of absolutely no consequence.
  10. TOP, You put words in my mouth. I never said the term "greenhouse" was a misnomer. I'm not saying I agree or disagree, because as Riccardo says, who the h-e-double--climate-hockey-sticks cares? It's a pointless debate. But you seem to have missed the point. Yes, you understand the purpose of the Wood experiment, but you have failed to understand why the design of the experiment was flawed. Please go back and read what I wrote. You are completely missing everything. As far as an IR-opaque atmosphere leading to global cooling... how the h-e-double-climate-hockey-sticks do you get that?
  11. TOP#1157 IR handhelds don't work that way. If you're not pointing at an object, it's not measuring anything. To claim a handheld can take the temp of the stratosphere is preposterous.
  12. TOP, G&T spend about 18 pages telling us what is already well known and understood as if they had some shocking new insight before getting into their own misconceptions. Science has known for a long time that the "Greenhouse Effect" is poorly named. The article is only about what is new that G&T assert.
  13. So, on the one hand, we have: - empirical findings of IR backradiation from the atmosphere measured from the surface; - empirical findings of IR wavelengths being blocked by IR-trapping (aka greenhouse) gases measured from satellites - empirical findings showing an energy imbalance at top-of-atmosphere, measured from satellites - empirical findings showing extra energy is rapidly building up in the Earth climate system (e.g. measurements of ocean heat content, ice melt, temperatures climbing) - other empirical markers of a rapid warming from meteorology and from ecology - experiment and known physics backing up all of the above And on the other hand we have TOP trying to tell us all that is wrong, wrong, wrong based on a few handheld IR thermometer measurements.
  14. @1162 scaddenp Maybe you can tell me in what section of their paper they propound a misconception? The paper has 115 pages. I'd like to know one misconception and the page and section it occurs in. Then we can have a meaningful discussion.
  15. Gee, where to start? Did you look at SoD? How about (from SoD) "In any case, a larger portion of the incoming sunlight lies in the infrared range than in the visible range. In most papers discussing the supposed greenhouse effect this important fact is completely ignored." Talk about a completely unsupportable (and wrong assertion). However, the core would be about validity the RTE and (to quote SoD) their "imaginary 2nd law". Again, conventional text book physics has no problem producing predictions that match observation. If G&T were right, then this would be impossible. I'll stick with the text book thanks.
  16. "the clouds have to be at a temperature above freezing to exist." That is incorrect. Temperature has to be at or below the dew point for any visible moisture to exist. Clouds can and do exist at temeratures at or below freezing. Liquid water can exist at air temperatures as low as -40 deg Celsius.
  17. TOP @1152: 1) You misquote Connolly as saying the troposphere is opaque to IR radiation. What he actually said is that it is "largely opaque to IR radiation". (My emphasis). That is easily verified by examining the downward IR radiation at the surface, as for example in these two spectra: You will notice that even with low humidity (Barrow Island), the atmosphere is essentially opaque to IR radiation outside the bands between wavenumber 800 and 1000, and between 1100 and 1200. With high humidity (Nauru) there are significant local emissions even in those bands. These facts were first discovered by the US Air Force, which conducted experiments in the IR transmission properties of the atmosphere so that they could effectively deploy heat seeking missiles. Consequently heat seeking missiles, and IR cameras, and IR thermometers are all tuned to the bands of low IR emission by the lower atmosphere. This model, for example, is tuned to the entire band of low atmospheric emissions, 8 µm to 14 µm (see spectral response under specifications). Arguing the atmosphere is not largely opaque to IR radiation because you can use an instrument tuned to the wavelengths in which the atmosphere least opaque is bizarre, although certainly not unique to you among fake skeptics. Neither is misquoting a source to strengthen your case. I hope both were accidental, and that you will now recognize that Connolly's claim was correct. 2) If known temperatures and humidities (from observations are fed into a Line By Line (LBL) radiation model, the result looks something like this: This is the result of an actual comparison between a LBL model and observations over the Gulf of Mexico. This is the same comparison with theoretical and observed spectra offset for clarity: Here is a detail of the first image with black body curves shown for clarity: You will notice that the absorption band of CO2 emits radiation consistent with a black body curve of 220 degrees Kelvin. As the Earth must on average emit energy equivalent to a black body curve of 255 degrees K to not continuously gain heat, it follows that that low emission must be compensated for by a higher emission somewhere else. Because of the absorption by water, the band in which that higher emission can come from is largely restricted to the area of IR transparency, ie, in which the radiation is coming from the surface. In order to emit IR radiation with a black body equivalence greater than 255 degrees K, the surface of the Earth has to be at at temperature greater than 255 degrees K. Ergo, the absorption of IR by CO2 forces the temperature of the surface to have a temperature greater than that which it would have had in the absence of the CO2. That was all simple physics, and follows immediately from the observed emissions, and the conservation of energy. No amount of experimentation with a toy box can prove these observations false, and therefore not amount of experimentation with a toy box can show that the greenhouse effect does not exist. In case you think that that observation/model comparison was cherry-picked because it was an unusually good fit, here is the scatterplot of 134,862 comparisons between measured, and modeled Outgoing Longwave Radiation (OLR) measurements: 3) A very minor point, but Wood's experiment was designed to show whether or not greenhouses warmed because of increase IR back radiation from the glass panels. His experiment successfully showed that they do not. It does not show, and is incapable from its design of showing, that the greenhouse effect does not exist. People who think it does do not understand the physics of the greenhouse effect. In order to successfully test whether a slab model of the IR effect is physically sound, you need to isolate the radiated surface (floor of the box) and the window (top of the box) by means of a vacuum. I do not believe it is possible to model the actual greenhouse effect as seen in Earth's atmosphere in so small a physical model. 4) Names are acquired through history and retained from convenience. Yes, the "greenhouse effect" is not in fact the effect that warms greenhouses. But neither are tin cans made from tin, nor are rubber ducks either rubber, or ducks. Get over it. If such trivia are all you have to criticize the theory, then that theory is very well grounded indeed.
  18. @1160 Sphaerica The atmosphere is densely packed with water vapor and CO2? Just what is the volume percentage of CO2 in the atmosphere? a) 40% b) 4% c) .4% d) .04% e) None of the above Hint: You will find the answer in G&T, Table 4, p.8. And I am glad you agree with G&T that the box experiment is not a good representation of the atmosphere. It is good to know G&T got something right. Now if you had said the box experiment did not agree with how greenhouses operate that would be a great flaw in G&T.
    2.6 Glass house summary
    It is not the “trapped” infrared radiation, which explains the warming phenomenon in a real greenhouse, but it is the suppression of air cooling."Falsification Of The Atmospheric CO2 Greenhouse Effects Within The Frame Of Physics", Gerlich and Tscheuschner, 2009, p34
    The purpose of the Wood experiment is singular, to determine whether radiation or convection controls the temperature of the air inside the box. The simple conclusion is that radiation has nothing to do with it. Glass completely blocks the escape of radiation. Rock salt allows all radiation to pass freely. With rock salt the box actually heats faster because the IR from the sun is allowed in as another forcing. @1157 muoncounter Sure I know how IR thermometers work. Can you explain to me how not to point an IR thermometer at something? Is the stratosphere a vacuum? Can you explain why pointing the IR thermometer at the sun does not register 5,800K? The IR thermometer integrates thermal energy within it's view cone by focusing it onto an IR sensitive transistor after filtering visible light. It uses the Stefan-Boltzmann law to back out the temperature (T&G eq.28, p.20). It doesn't care where the thermal energy comes from. Thermal energy doesn't carry little tags on it with it's origin stamped on it. Since pointing it at zenith allows it's view cone to take in the whole sky the area/radiant energy being integrated compensates for the low emissivity of the gases in the atmosphere above it. After all the reciprocal of the area of a 15deg included angle cone 29,000 ft away is about 2.2E-8 which is on the order of magnitude or smaller than the emissivity of the stratosphere. The farther away, the greater the area seen, and the more the low emissivity is compensated. The sun's emissivity is extremely low and it's apparent area is extremely small so it just doesn't register. So it is no coincidence that taking a reading of clear sky registers -55F or so on the IR thermometer which is experimental evidence that my hypothesis is right. Similarly when cloud if fully covering the view cone the thermometer measures something around freezing which is what I would expect cloud temperature to be (rain clouds anyway). And this line of reasoning is further backed up by the frequent formation of frost on my cars even when the air temperature is above freezing. The surface of the car and windshield radiates heat to a colder object, that being the stratosphere and space. If the car is under a tree, the frost won't form. In fact wikipedia mentions that IR thermometry is used to detect the presence of clouds. Same thing that I am doing.
  19. My hat off to you Sphaerica for your patience!!! TOP, if your experiments are so great that invalidates more than a hundred years of knowledge go ahead publish and become famous. Atmosphere is NOT opaque no matter how you look at it. The spectrum emission might look continuous but it is not. Atmosphere is NOT densely packed with water vapor. It is densely packed with N2 and O2. At 20oC the saturation at sea level is around 20,000 ppm of water, and we are now around ~400 ppm of CO2. I would say HARDLY densely packed. Actually above a certain height there is ONLY CO2 in the atmosphere (from the GHG ensemble). CO2 is much better well distributed compared to H2O.
  20. TOP. Have you read the notes at the bottom of this page - and followed the links? Could save you a bit of grief.
    Response:

    [DB] The NOTES sections are not accessible to the lay reader.

  21. TOP#1168: Thanks for tech summary on IR thermometry. I refer you to the specs for the Fluke 62, a top-of-the-line handheld: It reads as low as -30 C, a tad above the -48 C (225K) that you report for the temperature of the stratosphere. Also note "this rugged, compact thermometer takes accurate readings from up to six feet away." The D to S ratio is given as 10:1, so at 72 inches, you're reading a circular area 7.2 inches across. Beyond that, who knows what you're seeing? As for frost forming on the ground, surface air temps are standardized about 1.5 m above ground in screened enclosures - so that surface stations aren't contaminated by false readings. Cold air sinks. But you knew that already. You might read the text below the words 'Good Response by John Farley' in the Notes below, which gives specific examples of GT errors.
    Response:

    [DB] Please note that the NOTES section described by muoncounter is not viewable to the lay reader, so the relevant section is reproduced below:


    Good response by John Farley: Cockburn is impressed by a scientific argument, claiming that the greenhouse effect violates the Second Law of Thermodynamics.  He relies on a publication by Gerlich and Tscheuschner (GT), "Falsification of the Atmospheric CO2 Greenhouse Effects within the Frame of Physics."5  However, the greenhouse effect can be easily demonstrated in the laboratory.  The BBC broadcast a tabletop demonstration of the greenhouse effect, which can be found at the BBC website (at <news.bbc.co.uk/2/hi/science/nature/8394168.stm>).  The video, a little over 2 minutes long, is well worth watching.  Physics is an experimental science, and if theory disagrees with experiment, the theory must be flawed.

    But beyond noting that the GT theory is refuted by experiment, it is worthwhile examining where GT went wrong.  They claim that greenhouse gases in cold upper atmosphere cannot possibly transfer heat to the warmer earth, without violating the Second Law of Thermodynamics.

    Let's be clear about what Second Law of Thermodynamics does and does not say.  Suppose that you have two objects at two different temperatures, and suppose that light (visible or infrared) from either object can reach the other object.  There will be a flow of heat from the hot object to the cold object and a smaller flow of heat from the cold object to the hot object.  There are thus heat flows in both directions: from hot to cold and from cold to hot.

    The Second Law says that the flow of heat from hot to cold is greater than the flow of heat from cold to hot.  Hence the net flow of heat is from the hot object to the cold object.  Note that the existence of a smaller flow of heat from the cold object to the hot object does not refute the Second Law.

    At this point, we return to Cockburn's argument (from GT).  Heat flows from the warm earth to the cold atmosphere and also from the cold atmosphere to the warm earth.  (Heat also flows from the cold atmosphere to outer space, which is even colder.)  The flow of heat from the earth to the atmosphere is greater than the flow of heat from the atmosphere to the earth, so the net flow of heat is from the earth to the atmosphere.

    But there is also a (smaller) flow from the atmosphere to the earth.  This smaller flow keeps the earth warmer than it would be if there were no greenhouse gases in the atmosphere.  This is what the greenhouse effect is all about.  On this point, Cockburn has been misled by GT, who have advanced degrees in physics but have made a serious mistake in thermodynamics.

    Readers with a background in physics and calculus can read a comprehensive refutation of the GT paper by Arthur P. Smith, "Proof of the Atmospheric Greenhouse Effect."  Smith's article begins: "The results presented here are not new."  Indeed, they are over a century old and found in standard textbooks.  Smith has presented the subject in great detail in order to answer objections raised by GT to the treatment found in standard textbooks.

    The greenhouse effect has been known for over a century.  The greenhouse effect is quite a big effect: the Earth's surface is about 59 F warmer than it would be in the absence of greenhouse gases in the atmosphere.  The greenhouse effect was entirely natural until the industrial revolution.  In the last two centuries, the burning of fossil fuels has added a manmade contribution to the greenhouse effect.  It is surprising that the GT paper survived peer review, which is a quality-control policy that makes it harder to publish erroneous papers.  Harder, but evidently not impossible.

  22. @DrTsk I didn't say the atmosphere was opaque, Connelly did in a reference pointed to by muoncounter. (-snip-)
    ...the troposphere is largely opaque to infra-red radiation...[http://www.wmconnolley.org.uk/sci/wood_rw.1909.html]
    You can argue whether it is opaque or just largely opaque. But the Box experiment proves it is not totally opaque to IR. And G&T went into a lengthy discussion of the various (-snip-). Did you miss the question mark in my sentence? The correct answer was (d). It would certainly make sense that at some altitude H2O doesn't show up. I didn't do any experiments that invalidated anything. I'll leave that to G&T. @1167 Tom Curtis Tom, I have to deal with #4 first. If the term "green house effect" doesn't refer to the process by which green houses, cars and atrium skylights heat their interiors when the sun is shining, but instead refers to the supposed means by which the atmosphere keeps the planet warm, what name do you propose for the means by which green houses are kept warm in sunlight? T&G and the others they quote are absolutely right that this term has no business being used to describe what is going on in the atmosphere. (-snip-) I have seen all those curves before and that discussion on heat seeking missiles. The curves certainly don't support Connelly's largely adjective either. While I didn't include the adjective at some point, I did reference the source so it should have been clear what was being discussed. I'll have to apologize for that. I didn't see a curve for the incoming radiation from the sun or a computed specific intensity over the UV, visible and IR spectra at the ground. You would need to show that to make some headway with G&T. @1166 Chantreau A small point, but in a previous post I had stepped out and pointed my IR thermometer at the bottom of rain clouds which I think I mentioned then. I am aware that certain types of clouds like cirrus are comprised of ice crystals, but I was really referring to the clouds that usually pass over my location in which, yes, the temperature is below the dew point, but no, the temperature is not below the freezing point at whatever altitude they are at. Generally that only happens in summer and spring when hail forms. Clouds form when convection lifts warm air from the surface and the lapse rate then lowers the temperature of the moisture in the air to below the dew point.
    Response:

    [DB] Specious, argumentative statements detracting from the dialogue snipped.

  23. @1165 Scandenp From Table 8 on page 22.
    BandRangePortion
    [nm][%]
    ultraviolet0 − 38010.0
    visible380 − 76044,8
    infrared 760 − ∞45,2
  24. @1165 Scandenp From Table 8 on page 22 G&T come up with 45.2% of the energy arriving from the Sun as infrared. 44.8% is visible light and 10% is UV. It is just a standard calculation shown in equation 30. It is based on the sun radiating as a black body at T=5780K. G&T comment that the fact of this distribution is often overlooked in textbooks. He arrives at this by asserting that the Kirchhoff-Planck law is a more appropriate for evaluating sunlight. The Stefan-Boltzmann law is a special case of Kirchoff-Planck. So are you taking exception to his calculation of the portion of radiation received by the earth? Is there some alternative to considering the sun a black body radiator that is more correct? Now he is not saying that this is the spectrum you will see at the earth's surface. He also discusses and accounts for absorption at various wavelengths by the atmosphere. As far as books by Gerlich: (-snip-)
    Response:

    [DB] Off-topic snipped.

  25. TOP, First, the purpose of the Wood experiment is not to "determine whether radiation or convection controls the temperature of the air inside the box." The purpose is to determine whether or not in a system where convection is not present radiation alone will have the capacity to control temperature in the boxes. [This is a common — the most common — design for most experiments, by pinning down all variables except the one to be tested.] The experiment fails because it does not accomplish that goal. It does not remove convection from the system to allow only radiation to be a factor. The end result is that one cannot draw any conclusions from the experiment. Fortunately, numerous other, valid experiments have been performed, and this is why all educated scientists today understand GHG theory and dismiss things like Wood's experiment and the people who cling to it. But I asked you a question that you did not answer (or tried to answer snidely, while in the process failing completely to explain your logic): How can an IR-opaque atmosphere possibly lead to global cooling? What exactly do you think is going to happen?

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