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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)

 

At a glance

Although this topic may have a highly technical feel to it, thermodynamics is a big part of all our everyday lives. So while you are reading, do remember that there are glossary entries available for all thinly underlined terms - just hover your mouse cursor over them for the entry to appear.

Thermodynamics is the branch of physics that describes how energy interacts within systems. That interaction determines, for example, how we stay cosy or freeze to death. You wear less clothing in very hot weather and layer-up or add extra blankets to your bed when it's cold because such things control how energy interacts with your own body and therefore your degree of comfort and, in extreme cases, safety.

The human body and its surroundings and energy transfer between them make up one such system with which we are all familiar. But let's go a lot bigger here and think about heat energy and its transfer between the Sun, Earth's land/ocean surfaces, the atmosphere and the cosmos.

Sunshine hits the top of our atmosphere and some of it makes it down to the surface, where it heats up the ground and the oceans alike. These in turn give off heat in the form of invisible but warming infra-red radiation. But you can see the effects of that radiation - think of the heat-shimmer you see over a tarmac road-surface on a hot sunny day.

A proportion of that radiation goes back up through the atmosphere and escapes to space. But another proportion of it is absorbed by greenhouse gas molecules, such as water vapour, carbon dioxide and methane.  Heating up themselves, those molecules then re-emit that heat energy in all directions including downwards. Due to the greenhouse effect, the total loss of that outgoing radiation is avoided and the cooling of Earth's surface is thereby inhibited. Without that extra blanket, Earth's average temperature would be more than thirty degrees Celsius cooler than is currently the case.

That's all in accordance with the laws of Thermodynamics. The First Law of Thermodynamics states that the total energy of an isolated system is constant - while energy can be transformed from one form to another it can be neither created nor destroyed. The Second Law does not state that the only flow of energy is from hot to cold - but instead that the net sum of the energy flows will be from hot to cold. That qualifier term, 'net', is the important one here. The Earth alone is not a "closed system", but is part of a constant, net energy flow from the Sun, to Earth and back out to space. Greenhouse gases simply inhibit part of that net flow, by returning some of the outgoing energy back towards Earth's surface.

The myth that the greenhouse effect is contrary to the second law of thermodynamics is mostly based on a very long 2009 paper by two German scientists (not climate scientists), Gerlich and Tscheuschner (G&T). In its title, the paper claimed to take down the theory that heat being trapped by our atmosphere keeps us warm. That's a huge claim to make – akin to stating there is no gravity.

The G&T paper has been the subject of many detailed rebuttals over the years since its publication. That's because one thing that makes the scientific community sit up and take notice is when something making big claims is published but which is so blatantly incorrect. To fully deal with every mistake contained in the paper, this rebuttal would have to be thousands of words long. A shorter riposte, posted in a discussion on the topic at the Quora website, was as follows: “...I might add that if G&T were correct they used dozens of rambling pages to prove that blankets can’t keep you warm at night."

If the Second Law of Thermodynamics is true - something we can safely assume – then, “blankets can’t keep you warm at night”, must be false. And - as you'll know from your own experiences - that is of course the case!

Please use this form to provide feedback about this new "At a glance" section. Read a more technical version below or dig deeper via the tabs above!


Further details

Among the junk-science themes promoted by climate science deniers is the claim that the explanation for global warming contradicts the second law of thermodynamics. Does it? Of course not (Halpern et al. 2010), but let's explore. Firstly, we need to know how thermal energy transfer works with particular regard to Earth's atmosphere. Then, we need to know what the second law of thermodynamics is, and how it applies to global warming.

Thermal energy is transferred through systems in five main ways: conduction, convection, advection, latent heat and, last but not least, radiation. We'll take them one by one.

Conduction is important in some solids – think of how a cold metal spoon placed in a pot of boiling water can become too hot to touch. In many fluids and gases, conduction is much less important. There are a few exceptions, such as mercury, a metal whose melting point is so low it exists as a liquid above -38 degrees Celsius, making it a handy temperature-marker in thermometers. But air's thermal conductivity is so low we can more or less count it out from this discussion.

Convection

Convection

Figure 1: Severe thunderstorm developing over the Welsh countryside one evening in August 2020. This excellent example of convection had strong enough updraughts to produce hail up to 2.5 cm in diameter. (Source: John Mason)

Hot air rises – that's why hot air balloons work, because warm air is less dense than its colder surroundings, making the artificially heated air in the balloon more buoyant and thereby creating a convective current. The same principle applies in nature: convection is the upward transfer of heat in a fluid or a gas. 

Convection is highly important in Earth's atmosphere and especially in its lower part, where most of our weather goes on. On a nice day, convection may be noticed as birds soar and spiral upwards on thermals, gaining height with the help of that rising warm air-current. On other days, mass-ascent of warm, moist air can result in any type of convective weather from showers to severe thunderstorms with their attendant hazards. In the most extreme examples like supercells, that convective ascent or updraught can reach speeds getting on for a hundred miles per hour. Such powerful convective currents can keep hailstones held high in the storm-cloud for long enough to grow to golfball size or larger.

Advection

Advection is the quasi-horizontal transport of a fluid or gas with its attendant properties. Here are a couple of examples. In the Northern Hemisphere, southerly winds bring mild to warm air from the tropics northwards. During the rapid transition from a cold spell to a warm southerly over Europe in early December 2022, the temperatures over parts of the UK leapt from around -10C to +14C in one weekend, due to warm air advection. Advection can also lead to certain specific phenomena such as sea-fogs – when warm air inland is transported over the surrounding cold seas, causing rapid condensation of water vapour near the air-sea interface.

Advection

Figure 2: Advection fog completely obscures Cardigan Bay, off the west coast of Wales, on an April afternoon in 2015, Air warmed over the land was advected seawards, where its moisture promptly condensed over the much colder sea surface.

Latent heat

Latent heat is the thermal energy released or absorbed during a substance's transition from solid to liquid, liquid to vapour or vice-versa. To fuse, or melt, a solid or to boil a liquid, it is necessary to add thermal energy to a system, whereas when a vapour condenses or a liquid freezes, energy is released. The amount of energy involved varies from one substance to another: to melt iron you need a furnace but with an ice cube you only need to leave it at room-temperature for a while. Such variations from one substance to another are expressed as specific latent heats of fusion or vapourisation, measured in amount of energy (KiloJoules) per kilogram. In the case of Earth's atmosphere, the only substance of major importance with regard to latent heat is water, because at the range of temperatures present, it's the only component that is both abundant and constantly transitioning between solid, liquid and vapour phases.

Radiation

Radiation is the transfer of energy as electromagnetic rays, emitted by any heated surface. Electromagnetic radiation runs from long-wave - radio waves, microwaves, infra-red (IR), through the visible-light spectrum, down to short-wave – ultra-violet (UV), x-rays and gamma-rays. Although you cannot see IR radiation, you can feel it warming you when you sit by a fire. Indeed, the visible part of the spectrum used to be called “luminous heat” and the invisible IR radiation “non-luminous heat”, back in the 1800s when such things were slowly being figured-out.

Sunshine is an example of radiation. Unlike conduction and convection, radiation has the distinction of being able to travel from its source straight through the vacuum of space. Thus, Solar radiation travels through that vacuum for some 150 million kilometres, to reach our planet at a near-constant rate. Some Solar radiation, especially short-wave UV light, is absorbed by our atmosphere. Some is reflected straight back to space by cloud-tops. The rest makes it all the way down to the ground, where it is reflected from lighter surfaces or absorbed by darker ones. That's why black tarmac road surfaces can heat up until they melt on a bright summer's day.

Radiation

Figure 3: Heat haze above a warmed road-surface, Lincoln Way in San Francisco, California. May 2007. Image: Wikimedia Commons.

Energy balance

What has all of the above got to do with global warming? Well, through its radiation-flux, the Sun heats the atmosphere, the surfaces of land and oceans. The surfaces heated by solar radiation in turn emit infrared radiation, some of which can escape directly into space, but some of which is absorbed by the greenhouse gases in the atmosphere, mostly carbon dioxide, water vapour, and methane. Greenhouse gases not only slow down the loss of energy from the surface, but also re-radiate that energy, some of which is directed back down towards the surface, increasing the surface temperature and increasing how much energy is radiated from the surface. Overall, this process leads to a state where the surface is warmer than it would be in the absence of an atmosphere with greenhouse gases. On average, the amount of energy radiated back into space matches the amount of energy being received from the Sun, but there's a slight imbalance that we'll come to.

If this system was severely out of balance either way, the planet would have either frozen or overheated millions of years ago. Instead the planet's climate is (or at least was) stable, broadly speaking. Its temperatures generally stay within bounds that allow life to thrive. It's all about energy balance. Figure 4 shows the numbers.

Energy Budget AR6 WGI Figure 7_2

Figure 4: Schematic representation of the global mean energy budget of the Earth (upper panel), and its equivalent without considerations of cloud effects (lower panel). Numbers indicate best estimates for the magnitudes of the globally averaged energy balance components in W m–2 together with their uncertainty ranges in parentheses (5–95% confidence range), representing climate conditions at the beginning of the 21st century. Figure adapted for IPCC AR6 WG1 Chapter 7, from Wild et al. (2015).

While the flow in and out of our atmosphere from or to space is essentially the same, the atmosphere is inhibiting the cooling of the Earth, storing that energy mostly near its surface. If it were simply a case of sunshine straight in, infra-red straight back out, which would occur if the atmosphere was transparent to infra-red (it isn't) – or indeed if there was no atmosphere, Earth would have a similar temperature-range to the essentially airless Moon. On the Lunar equator, daytime heating can raise the temperature to a searing 120OC, but unimpeded radiative cooling means that at night, it gets down to around -130OC. No atmosphere as such, no greenhouse effect.

Clearly, the concentrations of greenhouse gases determine their energy storage capacity and therefore the greenhouse effect's strength. This is particularly the case for those gases that are non-condensing at atmospheric temperatures. Of those non-condensing gases, carbon dioxide is the most important. Because it only exists as vapour, the main way it is removed is as a weak solution of carbonic acid in rainwater – indeed the old name for carbon dioxide was 'carbonic acid gas'. That means once it's up there, it has a long 'atmospheric residency', meaning it takes a long time to be removed. 

Earth’s temperature can be stable over long periods of time, but to make that possible, incoming energy and outgoing energy have to be exactly the same, in a state of balance known as ‘radiative equilibrium’. That equilibrium can be disturbed by changing the forcing caused by any components of the system. Thus, for example, as the concentration of carbon dioxide has fluctuated over geological time, mostly on gradual time-scales but in some cases abruptly, so has the planet's energy storage capacity. Such fluctuations have in turn determined Earth's climate state, Hothouse or Icehouse – the latter defined as having Polar ice-caps present, of whatever size. Currently, Earth’s energy budget imbalance averages out at just under +1 watt per square metre - that’s global warming. 

That's all in accordance with the laws of Thermodynamics. The First Law of Thermodynamics states that the total energy of an isolated system is constant - while energy can be transformed from one component to another it can be neither created nor destroyed. Self-evidently, the "isolated" part of the law must require that the sun and the cosmos be included. They are both components of the system: without the Sun as the prime energy generator, Earth would be frozen and lifeless; with the Sun but without Earth's emitted energy dispersing out into space, the planet would cook, Just thinking about Earth's surface and atmosphere in isolation is to ignore two of this system's most important components.

The Second Law of Thermodynamics does not state that the only flow of energy is from hot to cold - but instead that the net sum of the energy flows will be from hot to cold. To reiterate, the qualifier term, 'net', is the important one here. In the case of the Earth-Sun system, it is again necessary to consider all of the components and their interactions: the sunshine, the warmed surface giving off IR radiation into the cooler atmosphere, the greenhouse gases re-emitting that radiation in all directions and finally the radiation emitted from the top of our atmosphere, to disperse out into the cold depths of space. That energy is not destroyed – it just disperses in all directions into the cold vastness out there. Some of it even heads towards the Sun too - since infra-red radiation has no way of determining that it is heading towards a much hotter body than the Earth,

Earth’s energy budget makes sure that all portions of the system are accounted for and this is routinely done in climate models. No violations exist. Greenhouse gases return some of the energy back towards Earth's surface but the net flow is still out into space. John Tyndall, in a lecture to the Royal Institution in 1859, recognised this. He said:

Tyndall 1859

As long as carbon emissions continue to rise, so will that planetary energy imbalance. Therefore, the only way to take the situation back towards stability is to reduce those emissions.


Update June 2023:

For additional links to relevant blog posts, please look at the "Further Reading" box, below.

Last updated on 29 June 2023 by John Mason. View Archives

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Comments 101 to 125 out of 1588:

  1. Phil, what is to explain there? The picture clearly shows a heat source (human body) emitting less heat where it is isolated. Unless you consider the earth to be it's own source of heat it has nothing to do with what needs discussed here.
  2. h-j-m, how do you explain the clothes staying cool when there is a warm body underneath them?
  3. Tom Dayton, because the clothes constitute the isolation I mentioned!
  4. Anyone who still doubts that CO2 absorbs infrared radiation should see this demo. A picture ... worth a thousand words. A video ... must be a thousand pictures!
  5. Re #104 muoncounter you wrote:- "Anyone who still doubts that CO2 absorbs infrared radiation should see this demo..." True, I don't know anybody who thinks CO2 doesn't absorb IR radiation. But there is a large number of people who believe they exist; rather like bad fairies, somewhere out there, trying to prove there is no greenhouse effect. I also know a lot of people who doubt CO2 doesn't emit infrared in exact proportion to the amount it absorbs... Now let us all think hard where these really strange people are to be found!
  6. Re #98 muoncounter you wrote:- "However, we know that both objects radiate, albeit at different wavelengths. Some of the cooler object's radiation is absorbed by the warmer; however, more total energy is transferred from warmer to colder." Which is fair enough, it is what your MIT link explains. And then for some bizarre reason you appear to make an exception for GHE radiative transfer :- "The 2nd Law is satisfied AND the greenhouse effect still works." (my emphasis) But the GHE requires that GH gases increase the temperature of the surface that is already hotter than the upper troposphere. (The troposphere can only get warmer than the surface in the exceptional condition of temperature inversion.) To get the surface temperature to increase the GH gases would have to cause, as you put it, 'a net transfer of total energy' from the troposphere to the surface. You also cite this post:- #83 CBD Your belief that this means energy can ONLY flow from 'hot' to 'cold' is simply nonsense, and rejected as such by all but the outermost looney fringe of modern physics. with favour. Surely you notice this post is in complete conflict with your MIT link?
  7. We often hear people say that GHG warms the surface. I understand its use in common language, but it's not to be taken litterally. Indeed they don't, they only reduce the outgoing flux. It's the unbalanced flux from the sun that makes the surface warmer.
  8. Re #107 Riccardo you write:- "I understand its use in common language, but it's not to be taken litterally." I do hope you don't mean this. Either the GHGs cause a warming of the surface or they don't. I have yet to read anything on the GH effect that doesn't posit an actual (literal?) warming of the surface. Since they are found in the atmosphere CO2 and H2O in the atmosphere actually are big players in radiating heat from Earth, you can see how much by looking at IR images of Earth here But the Earth wouldn't bake if there weren't any GHGs in the atmosphere. The average temperature would not be different, only the distribution of temperature would change, given the lack of heat transport from equator to poles by oceans and atmosphere.
  9. darmobel I meant exactly that. It should not come as surprise, often physics and common language share words with slightly different meaning. GHGs cause a change in the balance of the energy fluxes, but do not directly heat the surface. (Note the difference between energy and heat). It would be more correct to say that the greenhouse effect impedes cooling.
  10. h-j-m @101 So areas of the human body that are surrounded by clothes and hair emit less heat than those exposed ? Is that what you're saying ? I'm affraid thats not true. The part of the body under the clothes is emitting just as much heat as the exposed areas (the face, for example). But the clothes are clearly emitting less heat. Whats happened to the rest ?
  11. Re #109 Riccardo, you do not respond about the effect on the Earth's average temperature of removing all the GHGs from the atmosphere, will it go up or down?
  12. Phil, I just answered to your question which was about what a picture showed. The picture itself can only show an image of the radiation that arrived at the camera. Sorry, I thought that to be obvious. To deduce from a picture what it does not show is pure speculation. I try to avoid entering that realm.
  13. damorbel @108 You need to understand the difference between GHGs warms the surface and GHGs cause a warming of the surface These statments are different. My analogy with clothes may help you. Clothes do not warm your body, but they do cause your body to warm.
  14. h-j-m @112 If you refer to my post @98 I suggested you explain the temperature distribution, I did not suggest that you describe it. If you do not wish to try, then thats up to you, but doing so should help you with the errors you are making in your comments.
  15. Phil, I am referring to your posts #98 and #110. In your post #110 you state: "The part of the body under the clothes is emitting just as much heat as the exposed areas" and ask me to comment on this. Unfortunately you fail to provide any evidence to back that assumption. To explain something on the base of pure assumptions is called speculation in contrast to science where explanations are based on facts.
  16. #105: "a lot of people who doubt CO2 doesn't emit infrared in exact proportion to the amount it absorbs" You accept that CO2 absorbs IR, but now posit that it re-emits in 'exact proportion'? If that were true, why does the IR emitted by candle flame disappear when the CO2 is absorbing its IR? If emission were in 'exact proportion' to absorption, where is that emitted IR in the demo? Or does the IR absorbed remain as kinetic energy in the gas, resulting in increased temperature? -- A result completely consistent with all the other grade school level science experiments showing that a bottle with CO2 attains a higher steady state temperature than a bottle of room air. "But the GHE requires that GH gases increase the temperature of the surface" No, the GHE increases the temperature of the atmosphere. Your parsing of words and inserting phrases that aren't in the question is quite tedious; it isn't contributing to the actual debate -- which is, I suspect, your actual purpose in hijacking this thread. "Surely you notice this post (CBD's #83) is in complete conflict with your MIT link?" In what way? Be specific, without drifting into irrelevancies. This isn't a course in rhetoric. #108: "CO2 and H2O in the atmosphere actually are big players in radiating heat from Earth ... the Earth wouldn't bake if there weren't any GHGs in the atmosphere. The average temperature would not be different" Please substantiate these new claims with something more than a weather satellite image -- which doesn't illustrate whatever your point is.
  17. Re #113 Phil You wrote :- "Clothes do not warm your body, but they do cause your body to warm." Um... not true. While you are alive it is your (fuel burning) metabolism that keeps you warm, your clothing is an insulator that reduces the rate of heat transfer to the ambient, should the ambient be below 37C. If the ambient is above above 37C then you have problems because you cannot switch your metabolism off (well you can, but the problem is to switch it back on again) and, in the absence of any action to change the situation your body temperature may well rise to heatstroke levels. If you cannot switch your metabolism back on, your body will slowly settle to ambient temperature, what ever that happens to be. How long it takes to reach ambient depends on how good an insulator your clothes are. If you are put in a large vacuum flask with mirrored walls to reduce the radiative heat transfer then it might take days; without the mirrored walls - a day? The point is the insulator, be it a woolly blanket, a multilayer mylar sheet or a vacuum container, can only slow down the rate of heat transfer and thus the time taken to reach ambient. Your clothes keep you warm because you are continually replacing the lost heat with your metabolic heat - until you die, of course!
  18. Re #116 muoncounter You wrote :- "why does the IR emitted by candle flame disappear when the CO2 is absorbing its IR?" Because the IR from the candle is from a small, high temperature source and the CO2, absorbing the IR, warms only a little because there is much more of it. Given time and a sufficiently sensitive set up, the warming of the CO2 would be detectable - because the CO2 also emits IR and this would show up on an IR imager. A suitably sensitive IR imager may be able to resolve 1/1000K, such devices detect bodies under piles of concrete rubble when looking for earthquake victims. You wrote :- "No, the GHE increases the temperature of the atmosphere." When ever I have read about the GH effect it has been the surface temperature that was the worry. Sorry if I picked you up wrong! You wrote :- " "Surely you notice this post (CBD's #83) is in complete conflict with your MIT link?" In what way? Be specific, without drifting into irrelevancies." In #83 CBDunkerson wrote :- "energy flows into all surrounding objects regardless of their relative temperatures." Whereas the MIT link (section 2) has this :- "No process is possible whose sole result is the transfer of heat from a cooler to a hotter body" Now the reason 'sole result' is included is because heat pumps and refrigerators do transfer heat from a low temperature to a high one but they require another source of energy over and above the 'energy' they are pumping, thus the energy transfer the bring about is not the 'sole result' or sole action if you will. Thus CBDunkerson's statement contradicts your MIT link.
  19. damorbel, Solar energy arrives primary in the frequencies of visible & UV light. This passes through CO2 unimpeded. The planet absorbs the energy and re-emits it largely in the IR range (i.e. heat). CO2 and other GHG gases slow down the emission of these frequencies to outer space. This causes a increase of energy at the planet surface, and a cooling of the stratosphere since the rate of energy loss has slowed, until a new equilibrium is reached.
  20. #118: "Given time and a sufficiently sensitive set up, the warming of the CO2 would be detectable" Then your 'exact proportion' argument from #105 requires a very low constant of proportionality. And you accept that the gas is warmed -- please explain where this excess kinetic energy goes if the proportion emitted is so low. "I have read about the GH effect it has been the surface temperature that was the worry." Please tell us what you've been reading and what surfaces you appear to be worried about. "the reason 'sole result' is included is because heat pumps and refrigerators do transfer heat" Yes, I am sure Clausius had exactly refrigerators and heat pumps in mind. Perhaps you ought to state for the record: Do you accept the idea that greenhouse gases absorb infrared energy radiated from the surface of the earth and oceans, resulting in a warming of the atmosphere? Does CO2 play a major role in this process? If not, what are your specific objections? What published science (as opposed to vague references to individual interpretations of the 2nd Law) can you cite to support your objections?
  21. damorbel, you wrote: "If the ambient is above above 37C then you have problems because you cannot switch your metabolism off (well you can, but the problem is to switch it back on again) and, in the absence of any action to change the situation your body temperature may well rise to heatstroke levels." Of cause that is true in principle. But to my knowledge other actions take place as the body will shed water to increase the heat transport and in consequence the dehydration will lead faster to terminal conditions then the rising temperature. Anyway, I think this will be my last post here, The kind of reasoning here seems to give me headaches. I just happen to live in one world of which I assume it exists and is real. I have to confess that assuming an other world to exist and being real as well seems already too much for me. Switching between this two worlds seemingly according to which one fits the argument better makes it even worse. Let me jut explain these two worlds which I will just name here and there. Here matter absorbs radiation only at certain frequencies and is either transparent or reflects or scatters the rest due to its chemical composition. Here matter emits radiation at certain frequencies (producing something called colour at the visible range) again due to its chemical composition. Here I can feel the warmth of direct sunlight though that should be dwarfed by the earth's surface radiation not to mention back-radiation. Here temperature differences cause winds to blow, currents to flow, water to evaporate and in essence everything needed to sustain life or even to allow for its development. There all matter absorbs all incoming radiation which means that it acts effectively as a black-body. Consequently it also emits radiation where the according black-body spectrum, which only depends on the temperature of the black-body, determinates wavelength range and intensities. There temperature differences are the result of imbalanced energy flows which are caused by black-bodies emitting energy depending on the temperature of the black-body which again is caused by imbalanced energy flows etc. etc. ad infinitum. There is a world not only hard to understand but even harder to accept as real.
  22. h-j-m: Given: (1) that the atmospheric greenhouse effect is well-documented, empirically, as discussed on this website, other websites, and in the peer-reviewed literature; and (2) that the consequences of enhancing this greenhouse effect via anthropogenic emissions of greenhouse gasses - that is to say, global warming - also has a plentitude of empirical evidence to support it, as described on this website, other websites, and in the peer-reviewed literature; It would seem to me that there is not much question as to which of the below alternatives is more likely: - that all this empirical evidence (global cryosphere mass balance decline, sea level rise, changing migration patterns, pest prevalence in increasingly higher latitudes, temperature anomalies, &c &c &c) isn't really pointing to global warming via the atmospheric greenhouse effect - that you and damorbel have managed to misunderstand thermodynamics
  23. Re #121 h-j-m wrote:- "But to my knowledge other actions take place " A feature of this kind of discussion is the tendency not to see the bigger picture. My vision of man sized vacuum flasks was rather far fetched and any working version would probably stop any of your "other actions" so effectively that the death of the person inside would not be long delayed, thus illustrating the bodies return to equilibrium with the ambient temperature! I enjoy your contributions, you can express yourself on thermodynamics without difficulty. The trouble is few of your readers are able to appreciate what you are saying. For my part I try to explain, if I am not understood I try to work out why, because I would like to better explain these matters, especially for non experts. This is a serious ambition because there is a limited future in just talking to experts. There are plenty who will never accept that the AGW hypothesis does not hold together but others, who are genuinely interested, need to be supported by well crafted explanations, that is what I am trying to do here!
  24. Re #122 Composer99 wrote:- "the atmospheric greenhouse effect is well-documented, empirically " This thread is about inconsistencies in the well documented explanations of the greenhouse effect.
    Response: [Daniel Bailey] Just to be clear, you mean supposed "inconsistencies", with you being the supposer.
  25. Re #120 muoncounter, you wrote:- "Yes, I am sure Clausius had exactly refrigerators and heat pumps in mind." Clausius was not an ignoramus, he was almost certainly aware of refrigerators since a patent for a refrigerator was granted to Jacob Perkins in 1834, when Clausius was 12. you wrote:- "Do you accept the idea that greenhouse gases absorb infrared energy radiated from the surface of the earth and oceans, resulting in a warming of the atmosphere?" Perhaps 20% of atmospheric energy gets there by radiative transfer, of which CO2 accounts for perhaps 7%, another 20% by convection from the warm surface and 60% is due to water evaporating. In contrast about 80% leaves the Earth by radiation from atmospheric gases, of which 25% is due to CO2 and the remaining 20% by direct radiation from the surface. OK? Most of these figure come from the well known diagram of of K Trenberth, (I am having difficulty with the link - here's hoping!) they are the credible part of his diagram. The 'back radiation' idea is misconceived and certainly does not change the temperature distribution. Since the presence of H2O and CO2 etc. whose weak effects cannot distort the heat distribution, a distribution which is determined by much more powerful gravitational and cosine effects, exactly how the how the Sun's energy is absorbed is not of the first relevance. It is curious to note that Svensmark's cloud hypothesis has far greater traction than the GHG one. The death knell of the GHG hypothesis really is the effect of gravity on the atmosphere. The troposphere has a vertical temperature gradient which is a uniform 6.5K/km from the equator to the poles. This corresponds to the change of gravitational potential energy with height, it leaves no room for any radiative GH effect; it can even account for the rather strange temperature profile of the Stratosphere.

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