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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 1176 to 1200 out of 1393:

  1. @1171 muoncounter Fluke is a little rich for my budget. But my instrument reads lower than 30C. Is it accurate at that temperature? I don't know, never sent it out. Maybe all I can say is that my instrument reads at the bottom of it's scale. Still mighty cold. If you want to know what your IR thermometer sees fabricate a tube that gives a D-S ratio appropriate for your instrument. Then look through it. I will reiterate, an IR thermometer doesn't care where the photons come from or how far they travel. If you point it at the clear sky it will see the clear sky. Then it is a matter of it integrating the radiant energy in it's window. If my instrument sees a preponderance of gas at -55F or your Fluke sees a preponderance of gas at -30C it is still far colder than the air in the troposphere intervening. And it is very likely that a simple instrument like this sees a fairly narrow radiation band avoiding the CO2 and H2O absorption bands although the fact that it sees clouds suggests that the water band is included in it's range.
  2. "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." No. Wrong, and wrong again. Lowering the temperature of the moisture? And you comment about "GH effect" being a misnomer? How do you lower the temperature of a characteristic of the air? Please. Hail happens when turbulence carries large droplets above the freezing level in cumulonimbus clouds. Above the freezing level, it becomes ice, goes back down where it gathers another layer of liquid water, and up again, where that new layer freezes and so on. In very violent clouds, this cycle can be repeated so many times as to create hailstones the size of a grapefruit, which I personally witnessed in Fort-Worth in 1995. It can also be violent enough to make these stones "pop out" of the cloud and land many miles away, over an area where the storm seems distant enough that you'd be safe, sometimes even on an area overlaid by clear skies. If one finds an intact hailstone and slices it, the layers can sometimes be visible. Clouds do not happen only when air is lifted up and cools down, they form when air temperature is brought to the dew point, whatever the mechanism, and there are many. Contrails are caused by addition of moisture, saturating air that would otherwise not see the formation of clouds because it is too dry. Over the past few nights, where I live there were clear skies and the formation of low altitude clouds, sometimes going all the way to the ground (that's called fog), caused by radiation cooling. These clouds persisted through the rest of the night, and well into the morning; they were composed of water droplets, even though temperature fell below freezing. Cloud formation by addition of moisture is also common over large bodies of water in the fall, when the water remains warm enough to evaporate in cold, dry air. The possible combinations for cloud formations are in fact endless and can be very localized. I am not keeping my instrument rating current around here because the MEAs (google it) are high enough to be above freezing during most of the months when IFR conditions prevail. As a result, I would encounter icing (most likely rime ice, you can google that too) throughout all this time and would need an aircraft approved for flight into known icing conditions, and these are usually too expensive for amateur type of operations. These icing conditions happen precisely because clouds formed of liquid water droplets exist at temperatures below freezing. Then there is also supercooled water, you can google that too. Quite an interesting phenomenon. Although it is unusual, it does happen and will give you an instant coating totalling several hundred pounds to upward of a ton, depending what you're flying. "the fact that it sees clouds suggests that the water band is included in it's range." Isn't the water band for water vapor? Can you share your source for the specific range of IR emission for amospheric liquid water? Isn't it rather that these liquid water clouds only relfect radiation, a totally different process that your instrument can not discriminate? Methinks, you're talking about things that you have no true expertise about and that G&T have you fooled with their wordplay, because that's all their paper really is. Whatever.
  3. Oh dear. Sorry DB. Bit of brain fade today.
  4. "You can argue whether it is opaque or just largely opaque. But the Box experiment proves it is not totally opaque to IR." Just exactly what is the difference between "not totally" and "largely"? Sorry but that is just poor rethoric,especially from soneone accusing others to put words in his mouth. About this: "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." No, that's what not what the table says at all. It says that 45.2% of "Sunlight" (from the table's caption) received is within a certain range of wave length, 44.8% in another range and 10% in yet another. Not all wave lengths carry the same amount of energy, so the total amount of energy depends on how much of the spectrum is at what frequency and how much energy that frequency carries. Higher frequency photons are more energetic. If we were receiving 50% IR and 50% UV, guess which 50% would carry the most energy? Another indication of your lack of comprehension in these matters. By the way, is that repartition in table 8 at the top of atmoshere or at the surface? Do you understand why that matters? Do you know what the repartition is at the surface? If any difference exists, what does the difference tell us? I find it suprising that you could interpret G&T's table 8 as a distribution of energy. They don't suggest that themselves, despite their remark that the frequency (wave length) repartition is often overlooked. That remark itself is misleading; what matters in consideration of an atmospheric GH effect is the amount of solar radiation that reaches the surface, of which only a small portion is IR, precisely because of the fact that the atmosphere is largely opaque to IR, so most of the solar IR does not reach the surface. Which begs the question: why is there so much IR to be measured by instruments at the surface? Surely there has to be some work done by scientists to study this, don't you think? Have you looked for it? What is out there? On another note, the instrument to measure IR radiation is a pyrgeometer, different from an IR thermometer. The only thing you are demonstrating with your measurements is that there is indeed no violation of the 2nd law in the atmosphere. Quite a different thing than measuring how much downwelling IR radiation reaches the surface and what the overall energy balance is across the entire spectrum. The question is, when you use your instrument in the way you described, what exactly are you measuring? What physical quantity is represented by these numbers? How does that measurement contradict the existence of downwelling IR radiation from the atmosphere to the surface (as measured by a pyrgeometer)? Your way of approaching science is very much reminiscent of the people on WUWT who could not understand the phase diagram of CO2 and had to partially recreate the diagram before they could finally grasp that carbonic snow was not going to happen on Earth. The fact that you find in yourself the authority to attempt to pontificate on these subjects is truly srange. Nonsense on top of confusion, endless play on words, mangled semantics used as a basis for rethorical argument, it does not get better as time goes by. The more this thread goes on, the more it reveals about D-K effect, rather than atmospheric radiative physics. G&T knew exactly what the public out there is like, so they knew what they were doing and they should be ashamed for doing so much harm. To prove what? That they could play with words? that atmospheric scientists should be more careful with their language?Sheesh.
  5. TOP - I am perfectly capable of reading what G&T said. Are you capable of seeing what is wrong with that statement?
  6. TOP @1172: I retain the numbering of topics from my post 1167: Point 1) I refer you to the global energy balance by Trenberth et al, 2009: Upward IR radiation from the surface is 390 W/m^2. Upward IR radiation from the surface at the TOA is 40 W/m^2. Ergo, approximately 90% of all IR radiation from the surface is absorbed by the atmosphere. If you had a block of quartz which only let through 10% of the light shone into it, I am sure you would say it was "largely opaque". Why you are so determined to apply a different standard to atmospheres is beyond me. Point 2) The incoming solar energy is an irrelevant point. There is clearly less energy being radiated at some bands than at others in the IR spectrum. It follows that in those other bands, they must radiate at a higher intensity than they otherwise would have, and ergo the source of the radiation must be warmer. However, as noted in the diagram above, incoming, unreflected solar radiation is 239 W/m^2. Point 4) I am not going to try an reform the linguistic conventions of an entire language just because fake skeptics attempt to use those conventions to deceive people. Furthermore, I have seen how fake skeptics treat those who do try to reform the language. They take claims saying "greenhouse effect" is an inaccurate term and misquote them as claims that there is no greenhouse effect, ie, that the surface is not warmed by the presence of CO2 in the atmosphere. Everybody can understand that rubber ducks and tin cans are no longer made out of rubber or tin (respectively) but that the name persists. Everybody (almost) can understand that the ancient Greek theory of the four humours is false, and are not confused by people saying they are in "good humour", or that somebody has a phlegmatic personality. Likewise, everybody willing to think can understand that the warming of the surface by CO2 in the atmosphere is called the "greenhouse effects" due to a historical misunderstanding, but that that is consequently its name. They further understand that people trying to argue against a scientifically demonstrated physical effect based on coincidences of linguistic accident are intent on deceiving. Are you in that latter category? And if not, why are you making this an issue?
  7. So we're supposed to be willing to overthrow a well-known scientific principle on the basis of one hotly-disputed paper and a backyard experiment. If valid, from such discoveries come Nobel Prizes. The details of that experiment: - A measuring device costing less than $82 (current amazon.com price for a Fluke 62). - "Is it accurate at that temperature? I don't know, never sent it out." - "it is very likely that a simple instrument like this sees a fairly narrow radiation band avoiding the CO2 and H2O absorption bands" -- my IR thermometer has a quoted spectral response of 6.5 to 18 microns, which the figure below shows is not 'narrow band.' - the quoted range of such sensors is 6 feet or less -- works fine for checking AC/heating duct air temp. But if this is a credible experiment, tickets to Stockholm are in order. However, I wonder why NASA goes to all this trouble and expense designing and calibrating real narrow band (centered around 10.8 and 12 microns) IR sensors for satellites. Why not just put up a few hundred dollars worth of retail models? Oh, I forgot, they just do all this to boost their funding. Right.
  8. I'll add to what TC and Muon just said and make one bold statement: the measurements you obtain, considering how your instrument works, are entirely consistent with everything known of atmospheric radiative physics. They do not contradict the GH effect at all. In fact, knowing all the applicable local conditions at the time of measurement, they could be predicted from the physics. I'll leave it to you figure out why and how. You write here with the pretention to demonstrate that current understanding of atmospheric radiative physics is deeply flawed, there is then no doubt that you have the abilities to do that work. Then, you can explain exactly where the flaws are in the process used for the prediction.
  9. TOP - I would like to point out that every 'objection' you have raised has been discussed ad nauseum, and shown incorrect, in the previous thousand comments. G&T is a horrible paper, incredibly flawed, and the various "2nd Law of Thermodyamics" objections to the radiative greenhouse effect are simply not valid. At this point I consider the very fact that someone raises such objections to be a clear indicator that the proponent (a) lacks a sufficient education in physics, and (b) will grab onto anything that might even plausibly provide an objection to the science, regardless of validity. It's not (IMO) a promising sign. Please - read the Opening Post (OP), read through the thread a bit, go look at examinations of this topic such as the excellent work at Science of Doom (who has multiple threads on this topic). I think you might find a deeper understanding of this topic worthwhile.
  10. KR: Having followed the multiple, lengthy exchanges between TOP and you and other SkS authors, I am firmly convinced that TOP's sole purpose is to litter this comment thread with excerpts from the G&T paper. In my opinion, this behavior ought to be against SkS Comment Policy. If it were my call, I would ban TOP from posting on SkS and delete all of his comments.
  11. John Hartz @1185, I do not think merely presenting a view, however flawed, should be grounds for banning or deletion of posts. Continuous and repetitive presentation of the same point again and again should be grounds for deletion of further repetitions as of topic, but I do not believe TOP has reached that point, yet.
  12. @1171 Moderator I viewed the BBC experiment. Thanks for the notes. Among other problems: 1. Lights repositioned between 1:14 and 1:18 so that the CO2 light is more direct. 2. No control over the positioning of the lights. 3. The left bottle had .04% by volume CO2 while the right bottle probably had 90% by volume CO2 proving that CO2 absorbs more IR than air if the experiment actually represented equal impingement of IR on the bottles. All this would prove is that CO2 absorbs IR which nobody is disputing or perhaps that it takes an almost pure CO2 atmosphere to raise the temperature a few degrees. 4. The right bottle had an object behind it that may have reflected energy back into the bottle. 5. There was no control, no Design of Experiment and no statistically relevant reduction of data. This was just a snake oil presentation. This experiment simply proves, if anything, that CO2 absorbs IR, it has nothing to do with explaining why greenhouses warm in the sun. (-snip-).
    Response:

    [DB] Moderation complaints snipped.

  13. @1186 Tom Curtis Thank you Tom. I am trying real hard to make a reasoned point in a tough forum.
  14. TOP@1187 "There was no control, no Design of Experiment and no statistically relevant reduction of data. This was just a snake oil presentation." Are you serious? This was not a graduate thesis, this was a 6th grade level science demonstration. If you really want to *prove* that it is fabricated nonsense perform the experiment yourself. It should not take more than an hour start to finish and you probably have everything you need in our kitchen. Please post a youtube link when you are done. I eagerly await your results.
  15. @1185 John Hartz This is a discussion about G&T. Their paper is long and I saw little specific discussion of the points that they made that could be traced to specific parts of that paper. So I quote it. Frankly I don't think that a lot of the discussion on this whole thread has attempted to address G&T. And even when quoting G&T the discussion seemed to diverge from the topic of the post rather rapidly. I will say that I haven't found much of anything in the respondents to my comments here that convince me of the error of G&T's ways. I learn a lot but I see a lot of regurgitation of information found in other papers and books. Most of it just comes down on me for word choice or "rhetoric". Guess I'll have to take remedial English or writing. But then this is a blog and I would expect to be cut some slack on form and style like I cut slack for others. And if banning me is the only way to win the argument that speaks loads for the argument. G&T have made some headway. In 1184 KR uses the term "radiative greenhouse effect" which to me is acceptable in place of the "convective greenhouse effect" which is what happens in real greenhouses. And I will note that G&T wanted to use the term "atmosphere effect" in place of "greenhouse effect" when talking about warming the atmosphere by radiation.
  16. 1189 pbjamm Read my response. I don't have a problem with the science. CO2 does absorb IR. Look at muon's graphs and many others posted here. Those are actual measurements taken with expensive instruments. I do have a problem with calling it proof of the "radiative greenhouse effect" as applied to real greenhouses when real greenhouses don't typically have a 90% CO2 atmosphere. Perhaps that experiment should be called the "absorptive greenhouse effect". Mr. Wizard did a much better job of controlling his 6th grade experiments in the '60s.
  17. TOP@1191: I do have a problem with calling it proof of the "radiative greenhouse effect" as applied to real greenhouses when real greenhouses don't typically have a 90% CO2 atmosphere ======= Is this a purely semantic argument that 'greenhouse effect' is an inaccurate description? At this point I am not clear what you are arguing for or against.
  18. TOP - as has been said before, great hunks of G&T are telling us what everyone knows full well but possibly they and definitely you, seem to think contradicts how we understand atmospheric physics to work. The skeptic point to take down in their paper was their idea that 2nd law is being violated. It is not. Muon has pointed you at the spectral observations from both top and looking up. Both agree with model calculations which could not be valid if G&T were right. There is no observational evidence to contradict the GHE and a very great deal to validate it. Now, have you figured out what was wrong with the G&T statement I quoted earlier?
  19. Wow, almost 1200 comments in and we have consensus: It shouldn't be called the greenhouse effect because 'real greenhouses don't work that way.' In what way do these pedantics change the physical science involved - or the outcome? TOP#1187: Very insightful critiques. Now do the same with your 'I measured the temp of the stratosphere with my handheld IR thermometer experiment.'
  20. @1192 pbjamm It isn't semantics. The good BBC professor purported to demonstrate the "radiative greenhouse effect" by comparing temperatures in a) a bottle filled with air (0.04% CO2) and b) a bottle filled with CO2. The experiment did not demonstrate what was purported even a little. Nor did it invalidate Wood's experiment in 1909. You have read G&T haven't you? They have a big problem with the term "greenhouse effect", if for no other reason than it is not well defined, at least for a mathematical physicist's purposes and it is not an "effect". There are 14 subsections in their paper that find flaws in published definitions of the term in, I would hope, respected literature on AGW. G&T are arguing the "semantics" because without defining terms, what exactly is being discussed? What I say is of little consequence. And just a note of style, if you quote, put it in quotes or indent. As everyone knows, I am easily confused.
  21. TOP - we have no problem with idea that greenhouse effect is badly named. Its just not news. This in no way invalidates the fact the atmospheric greenhouse gases warm the planets. That IS the only point of substance for climate. SoD assumed G&T just skipped 100 years of literature; I think it more likely that they were trying to sow seeds of doubt about GHE with that long preamble. Looks like it worked. Are you arguing that IPCC science doesnt understand GHE. (eg as described here). Or that Ramanathan and Coakley 1978 (the basis for current calculations) have got it wrong?
  22. TOP, You still have not answered the question "How can an IR-opaque atmosphere possibly lead to global cooling?" I only ask again (for the third time) because I think that this may be at the heart of at least some of your problems. If you believe this, then there is something seriously wrong with your understanding of the physics involved. Please explain yourself.
  23. @1163, 1193 scadenp Well, I thought I did in 1174, but Philippe in 1179 pointed out that I incorrectly used the term energy for "Sunlight". It just all depends on what Blambda means when integrated as in equation 30 on page 22. It could just be power (energy per unit time) integrated over a portion of the spectrum. [I am being a bit imprecise here. You can look up Blambda elsewhere.] That table in G&T is referring to the black body radiation of the sun before it passes through the atmosphere. So of course the gases in the atmosphere are going to take their "cut" of the radiant energy on the way down. Wood demonstrated, however, that a significant and measurable portion of IR does in fact reach the ground. But muon's charts support this finding. Just out of pure curiosity, how does RGHE deal with the warming of CO2 from the sunlight? And why does muon's graph show such a low temperature in the CO2 notch looking down from above if there is so much radiant energy available to heat it? I have a thought on that but I am wondering what your opinion is.
  24. @1197 Sphaerica I think I just answered part of that in 1198. In the Wood (1909) experiment, there was a small discrepancy in how fast the two boxes heated. The box with the IR transparent cover heated faster. So I jumped to the conclusion that if that was so, and if placing an IR opaque filter in front of the box caused the temperature rise to drop, then the same would be true if the atmosphere were IR opaque (which it isn't, see muon's charts.)
  25. I genuinely have no idea what any of this has to do with violations of the 2nd Law of Thermodynamics.

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