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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

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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 401 to 425 out of 426:

  1. damorbel - My post on basic energy exchanges just demonstrated the principle of energy conservation, which your interpretation of the 2nd law of thermodynamics breaks. The more detailed discussion here simply extends that to the sun/Earth/atmosphere/space case. Gas compression is a red herring; irrelevant to the discussion. Temperatures and energy flows are deeply interrelated - more energy flows out of an object (or gas, or liquid) when it is warmer, less when it's cooler. Climate temperatures are the response and feedback to the total energy flows - net flows (summing all directions) as well as individual flows, such as the sun and atmosphere warming the surface. --- I did a bit of research, damorbel, and you have been pushing these incorrect ideas on the 2nd law of thermodynamics for at least 3 years. Given the number of people who have pointed out your errors without your understanding, I suspect you won't get the idea this time either. I would love to be proven incorrect - but educating you on this topic appears to be a Sisyphean task.
  2. Re #401 KR you wrote:- "My post on basic energy exchanges just demonstrated the principle of energy conservation, which your interpretation of the 2nd law of thermodynamics breaks." 1st Law of thermodynamics "Energy can be neither created nor destroyed. It can only change forms." 2nd Law of themodynamics The second law states that spontaneous natural processes increase entropy overall, or in another formulation that heat can spontaneously flow only from a higher-temperature region to a lower-temperature region, but not the other way around. In this case I agree with the Wiki article (apart from 'heat flowing') on 1st and 2nd laws of thermodynamics. PS you have noticed that I contribute to Wiki. But please be aware I personally am not the subject of this thread and I regard such comments as a waste of time and effort.
  3. 397 damorbel: "Would you like to reccommend some passage?" I'm not sure I understand the question nor, indeed, that I need to. Just though some people (clearly you are not excluded) might like some sources for clearing up some of these basic ideas - let alone the more complex ones! Looks like a good list of texts and comments on that. Hoping some knowledge flows in and some errors flow out :) 401 KR - see 367!
  4. damorbel - The issue with the 1st law of thermodynamics and your formulation is that you are ignoring the energy contribution of cooler objects (such as the atmosphere) to warmer objects (the surface), which increases the total energy in the surface and requires a higher temperature to radiate that energy away. Note that as long as the summed energy goes from warmer to cooler, which is true here, the 2nd law of thermodynamics is intact as well. Your claim that 'cooler objects cannot warm warmer objects' ignores that energy contribution, and hence breaks the 1st law - the energy from the cooler object doesn't just vanish. That means your claim is incorrect. My last comment is upon your intransigent position - you have received a great deal of input on this issue over the last 400 comments here and (looking around a bit) from numerous others over several years. Yet you still seem to think the radiative greenhouse effect violates physics.
  5. Dr Roy Spencer, contrarian and topic of this recent thread, posted an item on his blog last summer titled "Yes, Virginia, Cooler Objects Can Make Warmer Objects Even Warmer Still" and I thought it might be useful for both damorbel and KR et al. For damorbel it shows a contrarian showing "well, I’m going to go ahead and say it: THE PRESENCE OF COOLER OBJECTS CAN, AND DO, CAUSE WARMER OBJECTS TO GET EVEN HOTTER (sic)". For KR, and the rest, I thought it might be fun to read, in the comments, Dr Spencer trying to do your 'job' but without any reinforcements.
    Response: [DB] Please refrain from using all-caps. Thanks!
  6. MichaelM - I pointed damorbel to that article here, several months ago. His reply? "He's wrong." Hence my comments about intransigence.
  7. My apologies, I first directed damorbel that article in November, if not earlier.
  8. KR@406 The "he's wrong" post also shows damorbel doesn't understand that the surface is heated directly by the sun, so the "insulation" explanation is perfectly reasonable.
  9. Dikran - I attempted to address that particular misconception here with spectra, but was ignored.
  10. Re #404 KR you wrote:- "Your claim that 'cooler objects cannot warm warmer objects' ignores that energy contribution, and hence breaks the 1st law - the energy from the cooler object doesn't just vanish. That means your claim is incorrect." So are you saying that, if two equal blocks of metal, No1 at 300K and No2 at 320K were put in thermal contact, No2 would be >320K ?
  11. damorbel - Dynamic equilibrium, with energy flowing through the system, not static equilibrium; you have the wrong system in your example. Take instead a block of metal, heated on one side with 1KW of power, sitting on the other side on a huge block of ice. It will reach some dynamic equilibrium temperature, say 100 degrees. Now put a piece of wood between the block and the ice. The wood will reach a temperature between that of the block and the ice (and in fact will have an internal gradient), but the block (because of the slowed energy loss to the ice) will reach a temperature considerably above 100 degrees. A cooler object (wood) has warmed the warmer object (block) by reducing the energy lost, as that loss is only via the energy difference at the block/wood interface - much smaller than a direct block/ice interface. It has reduced energy loss by its presence, and hence warmed the block. Now substitute sun->1KW heater, Earth surface->metal block, GHG atmosphere->piece of wood, and space at 3K->huge chunk of ice.
  12. To expand on that - the final temperature the block reaches will be that temperature where 1KW of heat is passing through the wood to the ice. That's when the incoming/outgoing energies balance. The wood (by conduction) will pass some heat to the block, the block (by conduction) will pass a great deal more to the wood, 2nd law duly observed. The final substitution in my example is radiation for conduction.
    Response: [Dikran Marsupial] Added a "be"
  13. damorbel, Two questions. 1) Does an object have to be at a specific temperature in order to emit energy? 2) Is an object receiving energy selective to receiving energy only from objects warmer than them?
  14. "I am most interested in what you write but two lines is just a bit too little to give me a proper grasp of your point." An experiment is proposed. You use your understanding of thermodynamics to calculate a result. Result is also calculated by textbook thermodynamics. Results are compared to what actually is observed. If your method fails, then do you concede that your understanding is flawed?
  15. Re #411 you wrote:- "Take instead a block of metal, heated on one side with 1KW of power, sitting on the other side on a huge block of ice. It will reach some dynamic equilibrium temperature, say 100 degrees." But your system has a 1kW heat source on one side (of a block) and you add some insulator (the wood) to the other side. Of course the temperature will rise. The Sun/Earth arrangement has the heat source (the Sun) outside the Earth/atmosphere system. Although your model is set up with the Earth as a heat source this is not the case. My best model is the blanket. A blanket keeps you warm because it stops your body heat escaping, as a result you are warmer than the bedroom. If you die, your body heat stops and your body (now a corpse) cools down to room temperature. If the room temperature increases (because the Sun is making the room hot) the corpse under the blanket will get warmer too because it follows the room temperature. There will be a little delay in the change of the corpse's temperature because of the insulating effect of the blanket and the thermal inertia of the corpse but after a while thermal equilibrium will be restored. It is the same with the Sun/Earth system. The Sun streams out photons with a mean temperature of 5780K. But, because of the inverse square law, the density of (5780K) photons drops with distance (photons do not lose energy with distance - just the number/m^2 changes with distance), so the (average) temperature at a planet is dependent only on the distance from the Sun. Even if the planet reflects most of the Sun's photons (i.e. it has a very high albedo) that will only slow down the rate of heating by the Sun, the planet will just get to its final temperature more slowly (than a black body planet). PS the high albedo slows down the rate of cooling also. PPS the albedo works like a blanket, and just like MFI (Multilayer Foil Insulation).
  16. damorbel@415 wrote: "The Sun/Earth arrangement has the heat source (the Sun) outside the Earth/atmosphere system." what you don't appear to realise is that the atmosphere is largely transparent to the suns visible and ultraviolet radiation, which directly warms the Earths surface not the atmosphere. The atmosphere is warm not because it absorbs a lot of IR radiation from the sun, but from the IR radiated by the surface that has been heated by absorbing SW radiation from the sun and by conduction/convection. Thus the atmosphere is acting as an insulator, insulating the warm surface from the cold of space. This has been pointed out to you at least twice on this thread.
  17. damorbel - The sun is directly analogous to the 1KW heater - as I posted here the solar spectra passes through the atmosphere to the Earth, affected primarily by Raleigh scattering (not GHG's), and warms the surface. The analogy is completely correct, the energy flow is from the Sun to the surface and out to space through the atmosphere. A small amount of sunlight heats the atmosphere directly (your block heater touches part of the piece of wood in the analogy); that changes only in detail, not in essentials. And the atmosphere is a radiative insulator between the Earth and space. The surface of the Earth has an emissivity of ~.97 to .98 in IR, while the effective emissivity of the Earth and atmosphere to space is ~0.612; the insulation. And that insulation makes the planet warmer than it would be without the greenhouse gas atmosphere.
  18. Re #413 you wrote:- "1) Does an object have to be at a specific temperature in order to emit energy?" I am not being pedantic here! Objects do not emit energy, they emit radiation. The radiation they emit depends on the temperature of the body. Energy may or may not be transferred to other bodies even deep space; dependent on their temperature; energy may be transferred to the body in the paragraph above, again dependent on the temperature of bodies in range (deep space included) it all depends on relative temperature. You wrote:- "2)Is an object receiving energy selective to receiving energy only from objects warmer than them?" Does the first answer work here also? To sumarise: all bodies above 0K emit radiation; all bodies absorb radiation regardless of temperature; energy transfer takes place in the direction high temperature to low temperature - always!
  19. Re #416 KR you wrote:- "And the atmosphere is a radiative insulator between the Earth and space." Yes KR that is true. But the atmosphere is also between the Sun and the Earth, just like a blanket with a corpse underneath it is between the (ambient or Sun) heat source. If the Earth was itself a heat source then putting a (partially) reflecting layer round it would, like for a living body, keep the heat in and the temperature would rise. But the same (partially) reflecting layer would keep some of the Sun's radiation out. The temperature of the Earth is thus not changed by the albedo, just the rate of heating and cooling.
  20. damorbel - The vast majority of solar energy (shortwave) passes right through the atmosphere and warms the Earth. As Dikran Marsupial and I have both said, the atmosphere is warmed by the Earth, and hence the heater/block/wood/ice analogy holds, not your warming of a room through a blanket. The atmosphere is basically transparent to SW radiation, emitted by the sun based on it's temperature. The IR radiation emitted by the Earth, on the other hand, is almost completely blocked by the atmosphere. The atmosphere does not block sunlight from the surface, and for the purpose of discussion the sunlight could be coming from underground to warm the surface. To take it back to the analogy - the heater wires could run though the piece of wood, but they don't interact with it. Energy flows from Sun/surface/atmosphere/space, in that order.
  21. #418, Electromagnetic radiation is a form of energy. Trying to dance around words does not help your argument. Here's my point. We agree that all bodies emit and absorb radiation. If a source of a specific temperature emits radiation, what is there to prevent another source of higher temperature to absorb that radiation?
  22. damorbel - We've demonstrated how the atmosphere acts like insulation, to which you've completely agreed except for your objection about sunlight going through the atmosphere. We've then shown you how that isn't an issue with SW radiation, and that the heat goes from sun -> Earth -> atmosphere -> space. In other words, you have agreed that the atmosphere acts as insulation, raising the temperature of the Earth. Not to mention there have been multiple demonstrations the greenhouse effect via line by line integrations, energy balance models, energy conservation, and basic radiative and spectral physics. This includes a couple of simple models you have implemented yourself based on the text here. Since you've agreed with every step of the energy flow discussion here - are you still objecting to the greenhouse effect?
  23. Re 421 RickG you wrote:- "Electromagnetic radiation is a form of energy. Trying to dance around words does not help your argument." Rick, the 2nd law of themodynamics is about the direction energy transfer; radiation is the means of transport, not the transport itself. Radiation is specified by its amplitude, frequency and direction, this is insufficient to measure energy transfer. To find out about how much energy is transferred through a given surface a mathematician would integrate all radiation passing through it over time. What I disagree with is taking the different radiation components passing in one direction and calling that energy transfer. For thermal energy, to qualify as energy change it would need to cause a temperature change derived from the thermal capacity and amount of energy; tthat is the hole in the greenhouse argument. If you examine the GHE argument carefully you will find it claims a temperature rise as consequence of loss of energy, the fact that it is a loss is frequently hidden away with the phrase 'net energy' transfer, as good an example of 'dance around words' as you will find.
  24. Re 422 KR you wrote:- "In other words, you have agreed that the atmosphere acts as insulation, raising the temperature of the Earth." What is it about insulation that will 'raise the temperature' of anything? Sure when you have something with a temperature elevated above its environment, wrapping it in a first layer of insulation will slow down the rate of cooling but it won't increase the temperature. Adding a 2nd layer of insulation will slow down the rate of cooling further and the outer surface of the 1st insulation layer will become warmer but the final temperature will remain the same as the environment. If your 'something with a temperature elevated above its environment' is also a heat source, when you add a second layer of insulation the surface of the 1st layer of insulation will become warmer and the heat source itself might increase in temperature, depending on how it works. This is not very exciting stuff, perfectly normal common experience. I think your problem arises because gas compressed in a gravitational field has a temperature gradient, thus is the source of your so-called greenhouse effect. Now that really is counter intuitive and, since it involves gravitational energy, it isn't generally understood.
  25. Re 420 KR you wrote:- "the atmosphere is warmed by the Earth, and hence the heater/block/wood/ice analogy holds, not your warming of a room through a blanket." In #420 you said it yourself "solar energy (shortwave) passes right through the atmosphere and warms the Earth" If you blocked the Sun off (and you can) the Earth would cool. This is because the Sun is external to the Earth and its atmosphere. If instead the same amount of heat as given to Earth by the Sun was generated inside the planet, then changing the atmosphere, the emissivity etc. would affect the planetary temperature just the same as changing the number of blankets on your bed.

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