Talk:Greenhouse effect/Archive 3

Inconsistent

The figure showing scattering losses and absorption is very low resolution and does not show absorptions and windows in the mid-IR. Anyone have a better figure??

CO2 lifetimes

158.169.131.14 wrote:

NOT correct. The lifetime of CO2 is in the order of FIVE years, not hundreds. If you don't believe me, look at http://www.icsu-scope.org/downloadpubs/scope13/chapter01.html. This gives some figures. The atmospheric reservoir of CO2 is now about 750 Gigatonnes. Photosynthesis uses some 100 Gigatonnes/year (both land and marine plants). Exchange with the ocean comes to another 100 Gigatonnes/year. Lifetime is the reservoir size divided by turnover rate. Work it out yourself)

First of all 158.169.131.14 it woud be a good idea to get yourself an account. Second, to put comments like that in the talk page (here) not the article.

Secondly, your calculation of the lifetime is too simplistic. What is of interest is the lifetime of a CO2 anomalty in the atmosphere, not the individual CO2 molecules. See Greenhouse_gas; http://www.grida.no/climate/ipcc_tar/wg1/016.htm. IPCC tar says the lifetime is "5-200" years (FWIW sar says 50-200) and no single lifetime can be determined. It refers you to ch 3 for the details but they are elusive...

==: Please, IMHO, the lifetime of CO2 or any other atmospheric gas is not relevant to describing the greenhouse effect, nor is the precise quantitative measure of any energy transport method. These issues should be discussed somewhere else ... say for example news on global warming or in Atmosphere Chemistry. We should stick to known science and refrain from speculations in areas that are obviously still basic research. Tanuki

First Paragraph

How about: "The greenhouse effect, discovered by Joseph Fourier in 1824 and first investigated quantitatively by Svante Arrhenius in 1896, is the process in which the emission of infrared radiation by an atmosphere warms a planet's surface." When do I get my brownie points?

Millenddoug

Greenhouse effects is a compilated subject to understand. The whole cycle/process is very confusing. I hope staring at the computer page will help me understand. With confidence, Tino

Heat Transfer

The question of re-radition (or not) is not particularly important to an article describing the Greenhouse Effect. The right question to put is "Does the Greenhouse Effect require the transfer of thermal energy aka heat from the troposphere to the surface? And must this occur with sufficient intensity to raise the surface temperatue by 33C?" This transfer, should it be required, requires the extraction of heat energy from tropospheric gas at -19C, which would cool it further, and transferring it to a gas on the surface generally agreed to be at 14C or thereabouts; all this without any external work being done!--Damorbel (talk) 20:52, 8 October 2008 (UTC)

You are aware, I hope, that the whole system runs on solar power. I'm not sure what you mean by "without external work being done," but do keep in mind that there's an incident power of 1.3 kW/m2 driving the entire system. The whole system-- incident heating, greenhouse effect, convection, radiation--all comes from that incident energy falling downhill.

You ask "Does the Greenhouse Effect require the transfer of thermal energy aka heat from the troposphere to the surface?" If, by "transfer of thermal energy" you actually mean "transfer of net thermal energy, then the answer is no: energy flows both directions, but (by the Stefan-Boltzmann law) more energy flows from the surface to the upper atmosphere than flows from the upper atmosphere to the surface, so the net transfer of energy is from the surface upward. However, subtracting the downward flow from the upward flow means that the net flow upward from the surface is less than it would be with no atmosphere, and so the surface temperature has to be slightly hotter compensate, and to stay in thermal equilibrium. This is the greenhouse effect.

Clear? Geoffrey.landis (talk) 21:26, 8 October 2008 (UTC)

Having participated in the thermal design design of Earth orbiting satellites I am quite well aware of many matters connected with heat transfer. And you?

I've taught it. Geoffrey.landis (talk) 13:49, 9 October 2008 (UTC)

You say "If, by "transfer of thermal energy" you actually mean "transfer of net thermal energy, then the answer is no: energy flows both directions". Heat transfer is by nature "net", there is no other kind.

Photons move both directions, upward and downward. Net heat transfer is the difference between the energy carried by the two. If, as you say, you wish to define net heat transfer at the only kind of heat transfer (which you can do if you like to define it that way), then the answer to your question is "NO". The net heat transfer is from ground to atmosphere, not vice versa. The greenhouse effect reduces the net heat transfer upward, but does not make it go the other way. --GL

When a system is in thermal equilibrium there are no thermal transfer processes taking place, no temperature differences, no heat transfer, this is the basic science of heat and also common experience.

Should the Sun heat the troposphere, making it warmer than the Earth's surface, heat would be transferred by radiation from CO2, H2O etc. to the surface, this radiation would tend to cool the troposphere because it would remove thermal energy from it; the surface would tend to become warmer.

When the Sun heats the surface it becomes warmer than the troposphere thus heat transfers from the surface to the troposphere, this tends to cool the surface. But the lapse rate, more or less constant over the global surface, ensures that it is always warmer than the troposphere above. Where then is the mechanism that is supposedly warming the surface by 33C? There is nothing coming from the troposphere to the surface that is going to raise the surface temperature!

If the troposphere is at some temperature greater than 0K, it is going to radiate energy according to the Stefan-Boltzmann equation, P= epsilon sigma T^4 A. If you do thermal design of spacecraft, surely you are aware of this; this is the fundamental equation of heat transfer in vacuum. --GL

There is no interpretation of the redundant term "net" that is going to do this!--Damorbel (talk) 06:25, 9 October 2008 (UTC)

Oh dear, not this again. We can try the very very simple explanation, and see if it helps: "the earths surface receives radiation from two sources: the sun, and the atmosphere. It is therefore warmer than if it received radiation from the sun alone". Happy now? William M. Connolley (talk) 07:15, 9 October 2008 (UTC)

At night, the surface of the Earth cools much faster than the atmosphere. After an hour or so, the lower troposphere is warmer than the surface. The resulting radiation keeps the minimum nightly temperature higher than what would result without an atmosphere. This is easy to demonstrate by observing that clear nights are colder than overcast nights because clouds keeps the surface from cooling as fast. (They block the IR windows.) Q Science (talk) 15:41, 9 October 2008 (UTC)

"Oh dear, not this again". Who is claiming that there is no radiation from the troposphere? (I suggest "troposphere", it is more precise.) The whole of my contribution was about heat transfer, the predictions of the Greenhouse Effect are about temperature rise. It is the nature of the heat transfer that governs the rise or fall of temperature. Heat may or may not be transferred by EM radiation, the temperatures of the sources of EM radiation govern the transfer, the mere presence of EM radiation is insufficient to cause heat transfer.

If the Greenhouse Effect is confusing EM radiation with heat transfer then it is indeed necessary to look at "this again".--Damorbel (talk) 09:28, 9 October 2008 (UTC)

EM radiation, by which I assume you mean thermal infrared, is indeed a significant mechanism of heat transfer; and it's the one that's key in understanding the greenhouse effect.

"Darmorbal" wrote: "There is nothing coming from the troposphere to the surface that is going to raise the surface temperature!"

If the troposphere is at some temperature greater than 0K, it is going to radiate energy according to the Stefan-Boltzmann equation, P= epsilon sigma T^4 A. That's the law of physics; everything radiates. The troposphere too; no exceptions. If you do thermal design of spacecraft, surely you are aware of this; this is the fundamental equation of heat rejection in spacecraft. The analysis of the greenhouse effect consists of simply taking careful account of each of the mechanisms of heat transfer upward and downward.

All I can suggest is, do the thermal analysis before you continue. In fact, you can treat this as a spacecraft thermal transfer problem. Start by considering a thermal box in vacuum. Assume that it has an heat dissipation load of, say, 200 watts/m2. Assuming that this load is dissipated entirely by radiation, and let's assume an emissivity (epsilon) of, say, 0.65. What is the equilibrium temperature of the surface? OK, once you've calculated that, suppose that the thermal engineer decides that this is too low, and wants to increase the temperature by putting a single layer of MLI material around it. Assume that this MLI has an absorptivity (in the infrared) of 0.1, emissivity of 0.1, reflectivity 0.85, transparency 0.05. What is the surface temperature now?

Once you've come up with those two answers (equilibrium temperature with no MLI, equilibrium temperature with one layer of MLI material) we can move on and look at the case of planetary atmospheres. If, as you say, you've done spacecraft thermal transfer analyses, this one will be very easy. Feel free to use the Matlab thermal transfer module or even NASTRAN if you've got it (although it's hardly worth firing up NASTRAN for such a simple problem), but keep in mind that you need to make sure that the code you run includes emissivity, reflectivity, and also transparency for the MLI. Geoffrey.landis (talk) 14:12, 9 October 2008 (UTC)

Your equation P= epsilon sigma T^4 is that giving the power into a void at OK. To get the heat transferred between two surfaces you should account for the temperature of the sink also. You do this by taking the difference of the 4th power of both temperatures (T_a⁴ - T_b⁴). It is put better here: [1] where you can play about with some figures to convince yourself. --Damorbel (talk) 15:09, 9 October 2008 (UTC)

You taught thermal transfer and you used P= epsilon sigma T^4 as heat transfer? Did you mention that this only gives the heat transfer into 0K? For a real thermal analysis you need to replace T^4 with (T_a⁴ - T_b⁴).

As I said earlier, infrared travels both directions. When you say " you need to replace T^4 with (T_a⁴ - T_b⁴)", what you are saying here is that you need to account for the absorbed infrared flux as well as the emitted flux, so since the atmosphere is radiating downward a flux proportional to its temperature to the fourth power, you have to subtract a term for the downward flux.

Exactly. We're saying the same thing, two different ways. You're on the right track here.

So: can you solve the simple thermal equilibrium problem I posed earlier? Go ahead and solve it using an engineering simplification if you like, that's fine. Matlab may help. Once you solve the case of a simple single-layer insulation, you are halfway there to solving the greenhouse effect for a semitransparent atmosphere. I encourage you: do the numbers. There is no better way to understand the physics than to work through the problems, with numbers. Geoffrey.landis (talk) 03:03, 10 October 2008 (UTC)

What do you mean "Photons move both directions, upward and downward."? Do you feel that an analysis with photons will show that the cold troposphere is warming the Earth's hotter surface somehow? This is absurd! Did your students not pull you to bits about this? --Damorbel (talk) 15:59, 9 October 2008 (UTC)

You wrote (at least I presume it was you; it isn't signed properly) "The greenhouse effect reduces the net heat transfer upward, but does not make it go the other way. --GL" Would you care to describe just how you see the "Greenhouse Effect" actually reducing the net heat transfer upward? I have such difficulty accepting that a cold surface can make a net transfer heat by radiation to a warm surface in order to raise its temperature by 33⁰C. The IPCC claims this to be due to "backradiation" [2] , is there a conflict here? --Damorbel (talk) 16:43, 9 October 2008 (UTC)

Can we please take talk to the physics of the greenhouse effect off this talk page? This isn't an atmospheric physics class. - von Atmoz (talk) 17:18, 9 October 2008 (UTC)

Greenhouse effect isn't physics! I know for some it is just politics now but the logic Atmoz's suggestion there would be no place for the whole article. Do you have a reason for dumping the physics discussion, Atmoz? --Damorbel (talk) 17:28, 9 October 2008 (UTC)

WP:NOTFORUM and WP:SOAP come to mind. - Atmoz (talk) 17:36, 9 October 2008 (UTC)

Point taken. This is a controversial matter with manifest technical contradictions. I have attempted to place a section listing a small number; this section lasted a few minutes. Is there a Wiki policy on this? I understand that controversial matters in Wiki should have some place for sound objections, my objective for the moment is to check the matter out in order to be as constructive as possible, I have no taste for edit wars and so forth.--Damorbel (talk) 18:12, 9 October 2008 (UTC)

I have attempted to place a section listing a small number; this section lasted a few minutes. Don't know what you mean. Can you point to the diff please? the predictions of the Greenhouse Effect are about temperature rise - not really; we're mostly talking about steady state here William M. Connolley (talk) 07:51, 10 October 2008 (UTC)

The section I contributed (and its deletion!) it to be seen here [[3]] 8 minutes, even though discussed beforehand. Error - "a small number of deficiencies;

William, a "temperature rise" is also a rise when it is above the equilibrium. Being a knowledgeable authority on Greenhouse matters you will know that the alleged rise has been occuring with time also, but with a short perpective this appears as a "steady state".--Damorbel (talk) 08:52, 10 October 2008 (UTC)

Oh right, well your addition was obviously unacceptable. Lets try getting the time-dependent confusion out of the way: in the real world, things do vary with time, and the GHE effect varies as concnetrations of GHG's change. But we can forget all about that for a moment while we discuss the basics, specifcally your objection The greenhouse effect is described in this article as “ the process in which the emission of infrared radiation by the atmosphere warms a planet's surface”. Such a process would breach the second law of thermodynamics. So: we can consider the steady state. I wrote above: the earths surface receives radiation from two sources: the sun, and the atmosphere. It is therefore warmer than if it received radiation from the sun alone. Do you have any problem with that, in the time-independent case of an idealised non-rotating planet with only radiative transport? William M. Connolley (talk) 09:44, 10 October 2008 (UTC)

Mr. Connolley, you wrote (09:44, 10 October 2008) "time-independent case of an idealised non-rotating planet with only radiative transport? "Idealised non-rotating planet? with only radiative transport?" What is this? Yet another Greenhouse effect? Do try again, I know you can do better.--Damorbel (talk) 11:37, 10 October 2008 (UTC)

It seems like a better idea to study the idealised version first, and agree on that. Maths is below, also here, do let us know how you get on William M. Connolley (talk) 12:07, 10 October 2008 (UTC)

Geoffrey wrote (14:12, 9 October 2008) "In fact, you can treat this as a spacecraft thermal transfer problem" Not remotely, it is an planetary problem of multiple heat transfer processes in an atmosphere (gas in a gravitational field). The matters you mention are irrelevant to the defects I have identified. The Greenhouse Effect claims radiation from the troposphere raises the surface temperature above its equilibrium. I object to this because it requires a heat transfer process never previously observed. I invite you to substantiate the claimed warming effect in the light of my objection. You may of course agree with me, and let a note of my objection be put in the article.--Damorbel (talk) 08:28, 10 October 2008 (UTC)

It can be treated, in simplified form, as a very basic problem indeed. See the maths, which I provided here. Do you disagree with any of that? With your background you will have no trouble understanding it and pointing out any problems William M. Connolley (talk) 11:21, 10 October 2008 (UTC)

Checked your maths, provided here. Actally I looked in the archives [[4]] to find the full background. Your maths is good but it is the wrong physics. Heat flows according to the energy of the photons, i.e. the temp., not the intensity (W/m²) basics are here at hyperphysics. From this you should be sure you get the full meaning of the (T_a⁴ - T_b⁴) term. The explanation you gave in the archives just adds the intensities (W/m²) e.g. "the radiaton downwards at the sfc is S1 + erU^4" and "The radiation up is rT^4; hence rT^4=S1+erU^4 " But the heat transfer is zero unless T⁴ and U⁴ are different, this is what the hyperphysicslink is all about. I have been pushing the temperature hard because GH effect article does not pay attention to it. The argument is the same as that used by a certain Mr. A Einstein when explaining the Photo Electric Effect It is also the basis of the Second Law of Thermodynamics. --Damorbel (talk) 15:01, 10 October 2008 (UTC)

At night, the atmosphere is warmer than the surface. You are trying to use a static analysis and are ignoring the fact that the Earth turns. Q Science (talk) 17:57, 10 October 2008 (UTC)

Q: I certainly am, for these purposes, as a simplification. D: OK, good, we are onto the maths. I'm afraid its not clear to me exactly where you think the (simplified) physics is in error. You accept that (a) the downward radiation at the sfc is S1+erU^4; and that the upwards radiation at the sfc is (b) rT^4. Therefore, in my world, in equilibrium we must have the two terms being equal. You say "But the heat transfer is zero unless T⁴ and U⁴ are different" and refer me off somewhere else. I don't know what you disagree with. Once you have accepted (a) and (b) I don't see what you can do. Please write down what you believe to be the radiation balance of the sfc, in that situation. And if you use titles, get them right: E wasn't a Mr, of course William M. Connolley (talk) 22:28, 11 October 2008 (UTC)

The GHE article [[5]] claims:- "The surface temperature will rise until it generates thermal radiation equivalent to the sum of the incoming solar and infrared radiation" Because the so-called GHGs radiating in the troposphere are at a lower temperature than the surface, this warming claimed for the GH effect is contrary to Einsteins analysis of the Photoelectric Effect and the Second Law of Thermodynamics. The PE effect and 2nd Law both state very clearly that the lower temperature (thus lower energy) radiation cannot increase the temperature (energy) of material already at a higher temperature. To clarify the PE effect. Einstein noted that, however many (many = power) photons struck a surface, no electrons would be ejected unless the individual impacting photons had higher energy than surface (i.e. came from a hotter source). If you don't know about this you should get a course in quantum mechanics [[6]] In your calculations you bundle radiation from the Sun and the Troposphere without taking account of the different temperture of the sources (downward radiation at the sfc is S1+erU^4) S1 is radiation from a source @5780K, U is radiation from a source @254K S1 has no problem warming the surface to 288K but the Troposphere cannot warm the surface to 288K because it is only @254K, you should not really need QMech. to understand this.

A lot of words, but no substance. Once again: I've written down my surface radiation balance, from which my conclusions follow. I've asked you to write down yours, and you haven't. Please do (and for bonus points, also calculate your predicted surface temperature in terms of the given quantities) William M. Connolley (talk) 20:41, 12 October 2008 (UTC)

Ah, I think I see you mistake. Never mind, we can thrash it out later, for now just write down your sfc radiation budget and we'll take it from there William M. Connolley (talk) 21:38, 12 October 2008 (UTC)

By the way, Einstein did this work in 1905, almost certainly before he got his PhD since he submitted his thesis in April. [7] I think he published his PE paper [8] in March 1905, so it was perhaps Herr Einstein, not Mr. --Damorbel (talk) 18:09, 12 October 2008 (UTC)

Yes, if you're going to weasel out of not using Dr/Prof, you need to use Herr. In no way is Mr appropriate William M. Connolley (talk) 20:41, 12 October 2008 (UTC)

Radiate vs. reradiate again

The radiate/reradiate discussion seems to have dies down, but I present the following in case of a flareup. In the spring 2003 edition of the The Wilson Quarterly, V. Ramanathan and Tim P. Barnett describe the greenhouse effect as:

Atmospheric gases, such as water vapor and carbon dioxide, absorb infrared energy emitted by the planet's surface that would otherwise escape to space. These gases also emit infrared energy into space, but because the surface of the planet is, on average, much warmer than the atmosphere, the eventual result is a net trapping of infrared energy within the atmosphere. (Atmospheric gases absorb some incoming solar radiation as well, but this has only a negligible impact.) This reduction of the outgoing infrared energy by atmospheric gases is what we call the greenhouse effect.

Their description is very similar to the wording that is currently used in the lead and the basic mechanism section [9].- Atmoz (talk) 14:00, 11 October 2008 (UTC)

Ramanathan & Barnett make the same mistake as the Wiki article, even claiming an equivalence between the downward radiation/m² and that of a 250W lamp! No account at all is taken of the difference of temperatures, 254K for the Troposphere and 2700K for a tungsten lamp. As noted above, there can be no surface warming effect from radiation originating in the Troposphere on account of its lower temperature.--Damorbel (talk) 18:44, 12 October 2008 (UTC)

I suspect Ramanathan knows radiative transfer and its implications better than >99.999999% of Wikipedia editors. But if you're convinced he doesn't even understand basic principles such as this, you would be doing him a favor by emailing him with an explanation of how he's managed to get everything wrong for the past 40 years. Short Brigade Harvester Boris (talk) 20:08, 12 October 2008 (UTC)

I am not here to cite authorities. If you wish to believe that a cold surface can raise a surface already warmer to an even higher temperature by radiation then that is your belief, but it there is no experimental evidence for this. For more than 100 years this zany has only been found in the domain of perpetual motion, it will take a lot more than the GH hypothesis to displace one of the most solid laws in science. http://en.wikipedia.org/wiki/Second_law_of_thermodynamics#Quotes Good luck, but don't count on it!

Another thought, since there so much confidence in your guru. Have there ever been measurments to show this kind of heat transfer taking place? I mean, everything I have read on AGW seems to be based on this "back radiative heat transfer mechanism" and similar propositions such as the Earth emits as a black body. This latter is equally impossible. Most of the Earth's heat is emitted by CO2 and H2O vapour which are about as far from the black body model as you can get. --Damorbel (talk) 21:25, 12 October 2008 (UTC)

You've been raising this same tired issue for over a year now, and convinced no one. Has it not occured to you that perhaps you are the one who is misunderstanding thermodynamics? There is no conflict between the second law and the greenhouse effect. The only conflict that exists is the one you have invented in your head by misunderstanding the implications of the second law. Dragons flight (talk) 22:13, 12 October 2008 (UTC)

Dragons flight, may I have relevant details of what you object to in my contribution, then we can compare them? For the moment you seem to be hiding them! Do you have anything to say about the surface being warmed by the troposphere? Let us hear it! And be so kind as to give the version of 2nd Law of thernodynamics that you use (there are a number).--Damorbel (talk) 07:57, 13 October 2008 (UTC)

Raval, A. and V. Ramanathan (1989), Observational determination of the greenhouse effect, Nature, 342, 758 - 761, doi:10.1038/342758a0 - Atmoz (talk) 02:11, 13 October 2008 (UTC)

Atmoz, do you have full access to your link? I can't get a copy. Does it explain the warming process, or just the radiation balance?. If Ramanathan can show that there is a surface temperature rise due to radiation from the colder troposphere it would revolutionise science.

Further note for Dragonsflight. If the cold troposphere were shown to warm the hotter surface the whole of physics would be revolutionised! If you could show this you would become v. famous, you would wipe Einstein off the face of science! Is this what you mean by a tired issue . The fact that you don't recognise the importance of the issue would suggest that you haven't actually studied thermodynamics. --Damorbel (talk) 08:19, 13 October 2008 (UTC)

The cold troposphere was known to contribute heat to the warm surface in the 19th century (Arrhenius 1896 [10], and probably others). Hardly revolutionary. As to my objecions, you already have them in the previous times you have raised this nonsense. The second law deals with the systemwide transfer of energy. In a thermodynamically coupled system the net transfer of heat is always from warm to cold (in the absense of applied work). However, the internal transfers of energy can and do consist of both an upward and a downward flow and it is only the net transfer that is constrained by the second law. You repeatedly have said their can be no downward flow at all. This is simply wrong, and you have never given any justification for it other than repeating your tired interpretations of what you mistakenly believe the second law means. Dragons flight (talk) 15:01, 13 October 2008 (UTC)

For the surface to be warmed by radiation there has to be a net transfer of energy away from the troposphere to the surface. If the troposphere is colder than the surface, how does it happen? --Damorbel (talk) 19:53, 13 October 2008 (UTC)

No, the point of the greenhouse effect is that surface is warmer than if there was no atmosphere. The downward radiation from the troposphere partially offsets the radiation that the surface will emit regardless. It is still a net transfer from warm to cold, but the warm body disspiates heat less rapidly than if the atmosphere didn't exist and the Earth was simply radiating directly into space. Since the sun is ultimately pumping heat into the system, the ability to dissipate heat less rapidly due to the atmosphere has the effect of causing the Earth to reach a higher steady state temperature. Dragons flight (talk) 20:02, 13 October 2008 (UTC)

You suggest "the warm body disspiates heat less rapidly than if the atmosphere didn't exist" I think you are close to the real reason why the Earth is at 288K and not 254K. The argument for 254K is made here [[11]] but it has a serious defect, clear in the first line where it says "planet with the power emitted by a blackbody of temperature T". But the Earth is far from being a blackbody, it is covered with water, clouds and CO2, it reflects quite a lot of radiation (albedo) and has a very irregular spectrum [[12]] in the infrared, nothing "black" at all. The fault is in this formula $T=\left({\frac {L(1-A)}{16\pi \sigma D^{2}}}\right)^{\tfrac {1}{4}}$ the term (1-A) is equal to the absorptivity of a material "α" that is not perfectly black (the non absorbed radiation is the albedo). Kirchhoff's law states that, for a body in thermal equilibrium, the absorptivity equals the emissivity, (α=$\epsilon$). So the term (1-A) should be replaced by α/$\epsilon$=1 since a planet can only receive and lose heat by radiation. The equilibrium temperature is thus about (279+3)=282K (3K cosmic background). Thus by taking the correct emissivity there is no need postulate the questionable Greenhouse Effect to account for a massive 33K rise in surface temperature above a (supposed) equlibrium of 254K.

I already have a copy of your reference to Arrhenius 1896 [13], it isn't very clear that he describes the GHE as it is now understood, particularly the 254K equilibrium temperature. What seems to me the important mistake is not using Kirchhoff's law as his point of departure, i.e. the same mistake as the GHE. --Damorbel (talk) 08:39, 14 October 2008 (UTC)

So your argument here is because replacing 1-A with 1 gives 277 K instead of 255 K that ignoring the Earth's albedo is the natural way to explain our temperature of 288 K, and hence we should ignore all those details like the absoprtivity and reflectivity of the atmosphere and any notion of a greenhouse effect? Kirchoff's Law only implies that appropriately averaged over wavelength absorptance and emissivity must be equal, there is no requirement that they both equal 1. Dragons flight (talk) 09:17, 14 October 2008 (UTC)

"no requirement that they both equal 1." That is correct, it is only the ratio is also equal to 1, otherwise there would be a net heat inflow which could never escape and the temperature would always reach that of the source; however far away. No net outflow either because the temperature would then drop to that of the sink, 3K.

Any symmetrical object, even a glass or metal ball, illuminated by a star will stabilise at the equilibrium temperature of the given distance. The temperature distribution in the object may be such that only a small part is actually at this equilibrium temperature but that is another matter. For example, the atmosphere affects the surface temperature because gravity gives it a natural temperature gradient, the lapse rate. Because of this the average surface temperature is above the equilibrium. Venus has a much hotter surface because its atmosphere is 90 times more massive.

Kirchhoff's law is quite consistent with EM theory which states that all radiation absorption and emission comes from accelerating charges. For a planet it is the same accelerating charges that absorb and emit, there are no others!--Damorbel (talk) 11:41, 14 October 2008 (UTC)

$1-A\approx \alpha \approx 0.7$. Albedo is directly a measure of the reflectivity of sunlight and hence 1-A is directly related to the absorptivity of sunlight. You don't get to ignore the fact that 30% of sunlight is reflected back into space just because it would be more convenient in making your numbers work out. So the above gives 255 K. Dragons flight (talk) 16:28, 14 October 2008 (UTC)

That is OK if you can show that Earth radiates like a black body. But you know that most of the radiation comes from CO2 and H2O which only radiate in bands which mean its "coloured". A black body is the most efficient radiator possible, it is so efficient because it radiates in all bands with its characteristic shape. Gases aren't like a blackbody because there are gaps in their emission spectrum where no energy can pass, that why they are less efficient than a blackbody. A less efficient radiator will have to get to a higher temperature than a blackbody to get the same heat out. You remarked yourself "ability to dissipate heat less rapidly due to the atmosphere has the effect of causing the Earth to reach a higher steady state temperature". Well that is true, it is to a great extent because the atmosphere is a less efficient radiator than a supposed blackbody than the Earth, it is why the Earth is at a higher temperature than a black body emitter.--Damorbel (talk) 19:41, 14 October 2008 (UTC)

And now you are so close to describing the greenhouse effect... --Stephan Schulz (talk) 11:51, 18 October 2008 (UTC)

So close indeed but without GHGs. The full implication of Kirchhoff's law means that the equilibrium temperature is independent of the albedo, completely at variance with most versions of the GH Effect.--Damorbel (talk) 19:06, 19 October 2008 (UTC)

Question - Does Kirchhoff's law of thermal radiation apply to gases that also get heat from conduction? It seems that, in that case, the gas can radiate more heat than absorbed from radiation alone. Q Science (talk) 00:37, 20 October 2008 (UTC)

Yes, it can get a little confusing but Kirchoff's law still applies. Note that Kirchoff's law deals with emissivity, i.e., emission of radiation in proportion to that of a black body emitting at the same wavelength, and not emission. Same emissivity (per Kirchoff) but higher temperature = more total emission. Short Brigade Harvester Boris (talk) 01:19, 20 October 2008 (UTC)

Thanks Q Science (talk) 02:29, 20 October 2008 (UTC)

"get heat from conduction?" Kirchhoff's law of thermal radiation is for matter in Local Thermal equilibrium, i.e. no other heat source or sink, the condition closely reproduced in an orbiting planet--Damorbel (talk) 16:33, 1 November 2008 (UTC)

Re:

Gases aren't like a blackbody because there are gaps in their emission spectrum where no energy can pass, that why they are less efficient than a blackbody. A less efficient radiator will have to get to a higher temperature than a blackbody to get the same heat out.

I believe this comment in the talk above is an incorrect view of what is going on in greenhouse effect. The SURFACE of Earth is hotter, but the gases higher in the atmosphere --that absorbed heat from the earth-- are at lower pressure and hence temperature; the lower temperature they are radiating at is what makes them a less efficient radiator. I'm looking at sources now, to clarify this detail in the article (there is some mention of temperature differences, but it could be sharpened).ToolmakerSteve (talk) 09:16, 3 November 2008 (UTC)

Hi Damorbel. I've read quite a lot of this discussion, and don't pretend to understand most of the maths (I'm a biologist, we're generally not too strong on that stuff!). However, I do think I can see where you're coming from and would like to try an analogy to see if it helps.

As far as i can tell, the following is the crux of your argument - 'there can be no surface warming effect from radiation originating in the Troposphere on account of its lower temperature'. Now my understanding is that this comes from the net transfer of heat always being from hotter to colder (forgive the layman's terminology!).

This sounds to me a little like diffusion - which you probably know is the net movement of molecules from a region of higher concentration to a region of lower concentration by random molecular motion. However, while the NET movement is to the region of lower concentration, there are some molecules which do just the opposite (the motion is random!). The very fact that diffusion is the 'net' movement implies there is motion in more than one direction.

Hmm...not quite as clear as it was in my head (and not being a physicist there migh be something i don't know about that makes this analogy nonsense), but hopefully it will help. ````

It is actually simpler than that. In the morning the ground is colder than the atmosphere a few hundred feet above. (See Lapse Rate - Plot and Definitions, drag the zoom controls in the lower panel to see the morning temperature inversion.) Thus, every night heat follows from the atmosphere to the ground. This keeps the ground from getting as cold as it would without the atmosphere and results in an increase in the average surface temperature. The confusion results from applying static equations to a dynamic problem. Q Science (talk) 21:15, 13 November 2008 (UTC)

I like he explanations of the Lapse rate and the analogy of diffusion. These should be mentioned on these pages Greenhouse effect and Earth's energy budget.Veteran0101 (talk) 03:33, 10 December 2008 (UTC)

Thermal equilibrium vs steady state

The very first sentence in this article is wrong because it confuses thermal equilibrium with steady state. In thermal equilibrium there is no greenhouse effect, because that would be a violation of 2.law of thermodynamics and Kirchhoff law. This also seems to be a source of confusion for many people who discuss on this page. If Earth received certain amount of energy from the Sun and radiated this energy back to Sun, that would be thermal equilibrium; if it receives some energy from Sun and radiates this energy into [colder] space, so that its temperature stays constant, it is known as steady state.213.220.211.183 (talk) 10:45, 20 January 2009 (UTC)

Not sure what was supposed to be in thermal equilibrium but steady state makes more sense there. I've changed it.
—Apis (talk) 13:08, 20 January 2009 (UTC)

New Image

To begin with the solar radiation isn't 343 W/m² it's closer to 1370 W/m². And the new image describes all the heat flows as radiation, which isn't right either if I understand things correctly (latent heat, convection, etc)?. What was wrong with the old image?
—Apis (talk) 01:33, 24 January 2009 (UTC)

It is actually describing the net incoming radiation and outgoing. I removed it to prevent flaws with people who look at this image. It also describes it as "solar" and "infrared" which is in simple terms to describe the radiations rather than getting scientifically with "thermal". That is why I placed the old image in a more convenient place where it gets advanced and placed the simple version in the overview. ZooFari 02:23, 24 January 2009 (UTC)

343 = 1370/4. But I prefer the old image. -Atmoz (talk) 02:33, 24 January 2009 (UTC)

(ec)I'm sorry I didn't notice you had responded here & made changes to the picture. There are still problems though. Where are these figures coming from? they are inconsistent with the old picture. I'd expect the incoming radiation to be about 1370*0.7/4= 240 W/m² (albedo/reflected sunlight)... and the text isn't all that clear: "half the incoming solar radiation is absorbed by earth's surface", however there is no indication why (e.g. some absorbed by atmosphere, some reflected).

There is no reason to call it radiation when it's not exclusively that, you could call it heat or energy etc. I don't think the concept of radiation is any easier than heat or energy.
—Apis (talk) 02:49, 24 January 2009 (UTC)

Yes, I realized that afterwards. Well, I get where the numbers are coming from now, but I think the old picture was clearer and has more information.
—Apis (talk) 03:07, 24 January 2009 (UTC)

Well, if you suggest that the first image is clearer, I'll move the new image down to the descriptions and replace the old one in the overview. Sounds okay? Also, do you suggest I should use the term "energy", "heat" or "thermal"?ZooFari 03:10, 24 January 2009 (UTC)

Na, maybe just me that was tired and more used to the old one which is still there so I guess it doesn't matter. Could just say that the earth heats the atmosphere perhaps :S. Anyway I'm sorry for the confusion.
—Apis (talk) 15:24, 24 January 2009 (UTC)

Feedbacks section

I was halfway through improving the feedback section and my edit got reverted. I'd been asked to improve this section as a result of discussion on runaway climate change. Please could we discuss this issue here if it's likely to be controversial.79.65.143.193 (talk) 15:50, 6 February 2009 (UTC)

Sorry, my mistake. There have been a number of anonymous vandalizations of the article. I just saw an anonymous IP making large changes and misread the diff as a deletion, not an addition. Still, looking at it closer, I don't think this belongs here. It does not deal with the greenhouse effect per se, but rather with second-order and indirect effects. There is a see-main, a short summary of the material there is more than enough for the general article on the greenhouse effect. --Stephan Schulz (talk) 16:10, 6 February 2009 (UTC)

The main art is marked for deletion and as a result I've been asked to make changed to this article. Any chance you could revert the deletion and then hack my text about a bit?Andrewjlockley (talk) 16:15, 6 February 2009 (UTC)

Looking at Wikipedia:Articles for deletion/Runaway climate change, it's in no way certain that that article will be deleted (and if it is, the material is not lost, but still in the DB, and I or any admin can userfy it for you). I also find the material delete here to be severely unorganized, weasely ("some scientists", "many scientists") including indirect feedbacks (which really have nothing to do with the greenhouse effect), jumping back-and-forth, and using sources of limited quality and/or out of context. Some statements are unsourced entirely. This really looks like WP:SYN to me. Sorry. --Stephan Schulz (talk) 16:32, 6 February 2009 (UTC)

OK shall I have another go at it then?Andrewjlockley (talk) 17:04, 6 February 2009 (UTC)

I'd been asked to improve this section as a result of discussion on runaway climate change - dunno who said that but please don't treat it as blanket permission to change here. Whatn you've added, and S reverted, is unacceptable for the same reasons as RAC is unacceptable: Scientists, including James Hansen suggest that anthropogenic global warming may induce runaway climate change - this is not an accurate summary of current scientific viewpoint (how can it be, we don't know what RAC is). It would have to say something like "A small minority say...". The risk of this effect has led many scientists to suggest geoengineering. - again, unacceptable: geoeng is still a minority idea. Once started, runaway climate change will continue until the feedback loop is interrupted. For example, an ice-albedo feedback can only continue until all the ice has melted - this is nonsense. the expression runaway climate change is more commonly used in mass media than in scientific literature - (a) you shouldn't have to say that here. That should be in the RAC article (b) its only true in the sense of being a null set joke William M. Connolley (talk) 20:27, 6 February 2009 (UTC)

Hence my suggestion to re-work the insertionAndrewjlockley (talk) 13:34, 7 February 2009 (UTC)

"archiving"

I have "archived" (i.e. deleted) a whole pile of discussion, on the grounds that it has become clear that it was merely endless debate with no improvements to the article suggested or in prospect. Put it on your talk page, take it to usenet, but don't put it here. Whinge elsewhere William M. Connolley (talk) 21:26, 11 March 2009 (UTC)

I've done it again William M. Connolley (talk) 20:19, 12 March 2009 (UTC)

Yes, you have. Please undo what you have done.--Damorbel (talk) 20:12, 19 March 2009 (UTC)

Real greenhouses

"Various materials at times imply incorrectly that they do, or do not make a distinction between the warming effect and the mechanisms involved." Doesn't this mean that all this conversation is about subjective thoughts of the various sources on the internet?

This is how greenhouse works: "Why is greenhouse warmer than the surrounding? It uses sun energy to heat up and keeps the received heat inside. To be effective, it slows down all known thermal transfer mechanics; thermal convection, thermal radiation and thermal conduction. Adjusting the greenhouse temperature is made by adjusting the thermal convection; when all windows are closed, convection is fully blocked. Opening windows increases the thermal lost by convection and cools down the greenhouse. It is estimated that the major heat trapping is achieved by preventing convection; however, if either conduction or radiation is not prevented at all, the greenhouse will cool down to almost the same temperature than the environment. Therm "Greenhouse effect" is somehow misleading; blocking thermal convection is more important than blocking thermal radiation so actual greenhouse effect is playing smaller role in greenhouse. The effectiveness of blocking thermal conduction and thermal radiation is depending on the materials used to build up the greenhouse. Trapping thermal radiation is more valuable in environments where atmosphere moisture is low and night temperatures are also low. Big difference in environment and greenhouse temperatures increases the radiation loss greatly, especially if the heat can radiate directly to the space due to low natural greenhouse effect. Slowing down thermal conduction (insulating material) is more important when greenhouse is in windy environment and wind cools the walls quickly." —Preceding unsigned comment added by 213.216.225.18 (talk) 12:16, 15 December 2009 (UTC)

"This can be demonstrated by opening a small window near the roof of a greenhouse: the temperature will drop considerably"

That example does not demonstrate that a greenhouse functions by reducing convection, rather it demonstrates that if you let hot air out of a greenhouse, it will be replaced with cooler air from the outside. To prove that the greenhouse effect is due primarily to convection, one would keep the windows closed and run a fan inside a greenhouse, which would be and example of forced convection. Convection is the physical transportation of energy from one place to another. Convection will not occur unless there is a temperature difference between two locations. Once that energy is transported, it is either radiated or conducted away from there -- as it must in order to maintain the temperature difference that created the convection to begin with. Only if there is no temperature difference in a greenhouse will there be no convection (as can be the case for small greenhouses, but not large ones).

The article itself refers to the technical description of the greenhouse. In this article the choice of the material is based on retaining the
infrared radiation in the greenhouse. All long wave IR radiation (the heat) will be kept inside the greenhouse. 120.28.8.19 (talk) 16:03, 10 October 2009 (UTC)

Even if convection were suppressed inside a greenhouse (which would be desirable in order to reduce heat loss), the mechanism for radiation and conduction are not affected, and convection outside a greenhouse will cool it down every bit as much as convection inside a greenhouse. If the real greenhouse effect were due solely to suppressed convection, many tin roof half-round aircraft hangars should also exhibit the greenhouse effect, yet they do not.

It has also been demonstrated experimentally (Wood, 1909) that a 'greenhouse' with a cover of rock salt heats up an enclosure similarly to one with a glass cover

This information did not come from a peer-reviewed scientific journal, where the outcome has been replicated by anyone else in the scientific community. It is an example of an opinion and hearsay and therefore should be taken out of the article.

 That is not the point. Empirical data is convincing enough. The explanation for the rise of temperature is wrong, but I don't know if this
 information is in the article itself. It is only said that the temperature will rise according to the article. 120.28.8.19 (talk) 16:03, 10 October 2009 (UTC) 

"Greenhouses thus work primarily by preventing convection; the atmospheric greenhouse effect however reduces radiation loss, not convection"

If the atmospheric greenhouse effect operates differently from a real greenhouse, then it is not actually a greenhouse effect, but something else -- what is that "something else", i.e. -- if the "greenhouse effect" has only one meaning, then they are not operating differently, they are operating the same. If the "greenhouse effect" has more than one definition, that other definition was not conveyed.

Since the Earth exists in the vacuum of space, it cannot lose heat via convection or conduction, so it can only loose heat by radiation. If the atmospheric greenhouse effect "reduces radiation loss", that would imply that the Earth is not in steady state

The actual greenhouse effect is due to re-radiation of objects (or gases) as explained in numerous sites such as:

Planetary Radiation Budget and the 1-Layer Greenhouse Effect http://hope.simons-rock.edu/~geshel/physci134/1layer/1layer.html

Understanding the Greenhouse Effect http://www.ldeo.columbia.edu/~kushnir/MPA-ENVP/Climate/lectures/energy/Greenhouse_Effect.html

On the Phenomenon of Atmospheric Backradiation http://www.geocities.com/atmosco2/backrad.htm

Here is a quote from the above referenced (internet, not peer reviewed) article:

////"Fig. 1 reminds us that the temperature in the troposphere decreases with increasing height, and may also call to mind the Second Law of Thermodynamics (in Clausius’ formulation): “Warmth can never pass from a colder to a warmer body unless another related change occurs at the same time” (cf. Baehr, [11]), or more simply “Warmth can never spontaneously pass from a body of low temperature to a body of higher temperature” (see Schmidt, [12]). The Law may raise doubts about how “atmospheric backradiation” can work. In fact, properly considered, it already suggests that “atmospheric backradiation” is a mirage."//// The author of the internet page does not understand thermodynamics and radiative transfer. The imbedded quotations are gross oversimplifications, the kind of thing that is taught in grade school. Actually, to a scientific mind, they're idiotic. The term 'warmth,' besides having no scientific meaning, is meant to indicate the relative amount of thermal heat as measured by a temperature difference. Warmth has no relation to power or radiation in this context, power and radiation having scientific meanings. To understand back radiation, you have to understand various scientific terms: power, as in radiated power, thermal energy, thermal conductivity (zero in a vacuum), radiative power transfer (can occur in a vacuum), temperature (where differences in temperature drives thermal energy from one place to another place within matter where the thermal conductivity is non-zero, i.e. sufficiently large given the time scale of interest). Once you understand how these various properties interact, the concept of back radiation is quite easy to grasp. You just have to be careful, clear, and avoid completely terms that are not well defined. And you have to follow the long version of the laws (esp. in thermodynamics), the one that have all the contraints to be met, and those constraints are sometimes expressed in a single word- which of course can not be ignored or misinterpreted. I'll stop here until I get some feedback that shows interest in approaching the subject with the required level of rigor. blackcloak (talk) 08:18, 26 June 2009 (UTC)

• The above comment is a resort to the logical fallacy of ad hominem. We can dismiss an article because we think it isn't peer reviewed, but we cannot dismiss an article if it is constructed using scientifically accepted principles of reasoning. There are excellent bibliographic references at the end of the article for the claims made, and those would need to be discredited as well, in order to discredit the entire article -- and that has yet to be done. The peer reviewed journal, SCIENCE, is "Internet reviewed", so being being "Internet reviewed" does not prove something has not been peer reviewed or cannot be peer reviewed -- in fact, we are peer reviewing Heinz Thieme's article as we speak. See http://en.wikipedia.org/wiki/Peer_review. Furthermore, it is not enough to claim that the author does not understand thermodynamics and radiative transfer, you need to prove it. Mere say so is not enough and is another example of ad hominem. The above comment finally ends with a challenge that "I know all there is to know about this [supposedly] extremely complicated topic but I am not going to share my knowledge [even though that is why we are here] unless you act and think like I tell you to" -- to which Albert Einstein would reply that, “If you can't explain it simply, you don't understand it well enough”. Obviously that challenge was a dodge and evade for giving us any actual facts or simple explanations. I don't play that game, so if we eliminate all the ad hominem from the above comment, what is left of the argument above? Nothing, so let me add something to demonstrate just how simple the concept of backradiation is, and therefore how well I understand it. Presume the glass used in a Greenhouse is transparent to shortwave radiation and opaque to longwave radiation. Any radiation absorbed by the glass will be re-emitted in all directions equally, therefore 50% of the radiation absorbed by glass will be re-emitted back into the Greenhouse. If 100% of the Sun's predominantly shortwave radiation is absorbed and the re-emitted as infrared radiation by objects in a Greenhouse, the glass will absorb and re-radiate 50% of that energy back into the Greenhouse. So now the total energy received by the objects inside the Greenhouse will be 150% that of the Sun alone. Now 50% of that 50% will be absorbed and re-emitted back into the Greenhouse, and so on and so forth until the limit of this geometrical series is reached, at which point the total sum of energy in the Greenhouse will be 200% that of the Sun alone. This is what is called the Greenhouse effect by way of backradiation. —Preceding unsigned comment added by HY1802D (talk • contribs) 19:25, 30 June 2009 (UTC)

So? Go on. Finish your thought. Please. Do you see confirmation or contradiction? Don't make us guess. You know how to be direct, but can you be both complete and consistent? That is the question. (Sorry, poetic license.) blackcloak (talk) 02:24, 1 July 2009 (UTC)

• Tell me which word(s) didn't you understand in any of my comments and I will see if it is possible to help you answer your question. —Preceding unsigned comment added by HY1802D (talk • contribs) 20:43, 1 July 2009 (UTC)

Did I say I had a problem with any of your words? Rest assured I understood every one of your words. It's your sequences of words, while strung together in gramatically correct fashion, that don't seem to lead to a clearly stated, logical, unambiguous conclusion. For instance, are you saying that one may infer that the 200% number means that conservation of energy is violated and therefore your (counter) example forces us to conclude that back radiation can not be the correct (dominate) explanation for the greenhouse effect? There are a bunch of other points in your discussion that should be challenged, but, before I attempt to show you where you've made mistakes, I want to understand precisely where you are trying to take us with your reasoning. blackcloak (talk) 08:25, 2 July 2009 (UTC)

One of the many points I made is that just because the temperature of greenhouse will drop "considerably" when opening a small window near the roof of the greenhouse, does not prove that a greenhouse heats up due to lack of convection, as the Wikipedia article still incorrectly points out. No, to prove that assertion would require keeping the window closed and putting fans inside the greenhouse to see if the temperature would drop considerably -- as it must if the greenhouses-work-by-suppressing-convection "theory" were true. But of course the blind faith assertion that the greenhouse effect is due to a lack of convection isn't true at all, as evidenced by actual greenhouses in which convection is encouraged. A simple Google search for "greenhouse circulation fans" will reveal an overwhelming number of examples of actual greenhouses with circulation fans in them. Seeing as convection is a low volume phenomenon, the high volume circulation fans should completely destroy the greenhouse effect, but they don't. Is that simple enough for you, or do you need a still simpler explanation -- I can draw pictures for you if necessary (HY1802D (talk) 01:19, 2 August 2009 (UTC))

I need a more coherent, not simpler, explanation. But just to set the record straight, let's figure out what your understanding is of the phrase "greenhouses-work-by-suppressing-convection." Is it your understanding that the phrase refers 1) to convection of air inside the greenhouse (i.e. outside air is not relevant), or 2) to preventing convective flow between air inside the greenhouse and the air outside the greenhouse? Please answer by telling us if you believe the phrase refers to number 1 or number 2. You don't have to say anything more, except if neither description matches your understanding. Your record of responding to questions directly is very poor. This makes you look like your modus operandi is evasion, which suggests that you have ulterior motives for participating in this forum. blackcloak (talk) 19:24, 6 August 2009 (UTC)

This explanation is very consistent with what the rest of the scientific community has always claimed about the greenhouse effect, and it is the same explanation given for a real greenhouse, as is for the atmospheric greenhouse effect. Furthermore, if you look at the radiation budget for the Earth, convection only accounts for 7% of that budget, whereas the rest is accounted for by other things such as the greenhouse gases. —Preceding unsigned comment added by HY1802D (talk • contribs) 22:02, 10 June 2009 (UTC)

"This mechanism is fundamentally different from that of an actual greenhouse, which works by isolating warm air inside the structure so that heat is not lost by convection." , needs a reference of convection based heat-loss on the earth unless only the surface temperatures are meant... Does the nightside of the earth lose molecules and atoms more than the dayside, what is the difference? True the convection rises water vapor which then rains but does this happen in the planetary level?? True the energy of the vaporization takes temporarily cools the nearby surface temperatures. 85.156.31.132 (talk) 07:04, 20 June 2009 (UTC)

• Suppressed convection is not the principle by which the greenhouse effect works -- neither in greenhouses nor for the Earth's Radiation Budget. Visit the links I posted above and read the proper explanation of the greenhouse effect as given there. —Preceding unsigned comment added by HY1802D (talk • contribs) 01:14, 2 August 2009 (UTC)

Ok, so after all this discussion, why does the article continue to insist in the lede that "This mechanism is fundamentally different from that of an actual greenhouse, which works by isolating warm air inside the structure so that heat is not lost by convection." Quite apart from the many objections to this claim raised above, the Wikipedia article Solar greenhouse itself cites as the two main mechanisms of a solar greenhouse "1. Thermodynamically isolate the system to stop convection and conduction from equalizing the inside temperature with the outside temperature. 2. Provide a covering with a controlled difference between the transparency in the solar radiation band (280 nm to 2500 nm wavelengths) and the terrestrial thermal radiation band (5000 nm to 35000 nm), for the purpose of either raising or lowering the temperature inside the greenhouse." With regard to the latter it says "A greenhouse covering which is more transparent to the solar radiation band and less transparent to the thermal radiation band will result in a temperature higher than the surrounding environment, and a greenhouse covering which is more reflective of solar radiation and more transparent to thermal radiation will lower the temperature relative to the surrounding environment.[1]"

Conservatives needing an outlet for their pet theories of how greenhouses "really work" have Conservapedia at their disposal for such misinformation; please use it, it is an excellent way of avoiding Wikipedia articles that flatly contradict each other. The Conservapedia article on greenhouses claims that "The heat comes from sunlight's infrared spectrum, which is used in the heat lamps that keep McDonald's french fries warm." This raises the interesting question, if thermal radiation (the kind McDonald's uses) comes from sunlight, what happens to the solar radiation (280 nm to 2500 nm) constituting over 98% of the heating energy of the Sun even before it reaches Earth? And how does this thermal radiation get through the atmosphere, which is opaque to thermal radiation but transparent to solar radiation? The truth of the matter is that the earth is heated essentially entirely by solar radiation defined as radiation from 280 to 2500 nm. The sort of thermal radiation used by McDonald's, which is at a wavelength an order of magnitude longer than solar radiation, is a really tiny component of sunlight's spectrum that contributes essentially nothing to the warmth of the Earth! No wonder conservatives are so muddle-headed about science when they run around repeating made-up science factoids like that to each other. --Vaughan Pratt (talk) 02:50, 7 November 2009 (UTC)

Meanwhile I put more thought into this and concluded, to my embarrassment, that those of us for whom it was obvious that so much far infrared (FIR) radiation was blocked by glass are basing their reasoning on the assumption that the alternative escape routes for the FIR, namely convection and conduction, are only a feeble replacement for the radiation path, whence there must be a nontrivial build-up of heat. It occurred to me last night that this model was wrong, and that at FIR wavelengths, here 5-80 microns, glass itself is a black-body radiator, just like a black glass stove top, as well as a sufficiently good conductor for the radiation blocking action to be almost irrelevant, at least for glass of conventional thickness if not inch-thick glass.

What I now believe really happens is that, when warmed by the Sun, the interior radiates FIR radiation at say 55 C (the temperature Wood measured for his 1909 experiment) that fills the greenhouse uniformly while being blocked from radiating to the outside by the glass, which is completely opaque at those long wavelengths. The inside surface of the glass is immediately raised to the identical 55 C, with no assistance needed whatsoever from convection. (That's one very hot greenhouse, feasible on a hot day but too hot for most plants, so you'd take cooling measures if it did get that hot.) The heat on the inside surface then propagates by conduction to the outside in its own sweet time while crossing a temperature differential across the glass of around one degree C. On the outside it reverts to black-body FIR at 54 C, from where some 70% of it is radiated away and the remaining 30% is convected away. Global warming does not work that way because although the FIR-blocking action of the CO₂-bearing atmosphere is analogous to that of glass if not as strong, it has nothing like glass's significant thermal conductivity to compensate for that blocking action. More details at Talk:Solar greenhouse#Making_sense_of_Wood.27s_experiment. --Vaughan Pratt (talk) 00:54, 18 November 2009 (UTC)

I can see you're attempting to reason this through. But I'm sorry, statements like "alternative escape routes for the FIR, namely convection and conduction" just don't make physical sense. It might help for you to read a good introductory textbook that explains energy transfer processes in the atmosphere and near Earth's surface. Wallace and Hobbs is a good start if you know calculus. Short Brigade Harvester Boris (talk) 01:37, 18 November 2009 (UTC)

Ray, if you prefer we can switch to WP:CIVIL-speak, just give the word. Meanwhile, your objection is the physics counterpart of complaining that the assignment x=n is badly typed because x is a float while n is an int, which is to say you're complaining because I didn't cast it as x=(float)n. I'd assumed it would be obvious to a reader with a basic understanding of heat that radiant energy (whether coherent or blackbody) incident on an opaque thermally conducting plate would heat the plate, i.e. be coerced to an incoherent form of thermal energy, be conducted through the plate (by exciting its molecules), and emerge from the other side as black-body radiation. That the coherence of the outgoing radiation is necessarily that of the incoming radiation if and only if the plate is optically transparent at that wavelength might have to be postponed to a later module on heat. Other related situations call for other such coercions.

I must say you had me mystified about Wallace and Hobbs until it occurred to me that perhaps you'd forgotten that this section's heading is "Real greenhouses." Or do W&H say something that would contradict the one sentence I wrote on this page that had anything to with the atmosphere?

When academics like you and me can get bogged down like this on square one of heat, imagine what the general public has to wrestle with. --Vaughan Pratt (talk) 04:39, 19 November 2009 (UTC)

Talking about wrestling, I continued to wrestle with why Wood's 1909 experiment should have turned out that way, and finally decided the question couldn't be answered without trying to duplicate Wood's experiment. This being WP:OR by me, any conclusions that might eventually be drawn here aren't suitable for the article, but they do raise the interesting question of why so much credence has been given to so little experimental evidence bearing on whether trapped infrared radiation plays a significant role. --Vaughan Pratt (talk) 10:26, 29 November 2009 (UTC)

Why remove so much?

Boris, that is about half the article. I understand if you then link to the information elsewhere, but you didn't provide a link. What's up? Q Science (talk) 04:18, 7 July 2009 (UTC)

It was just an unreadable mess -- not literally unreadable in the sense of not being parseable as English, but redundant and confusing. It was too convoluted for the layman and yet not meaty enough for an expert. I think the "basic explanation" is enough for this article and then we can go on to discuss anthropogenic effects, greenhouse effects on other planets, comparison to real (agricultural) greenhouses, and so on.

Arguably there is room for a more detailed explanation but I considered the material beyond repairing in the usual incremental way -- better to blow it up and start from a clean slate. Short Brigade Harvester Boris (talk) 04:44, 7 July 2009 (UTC)

It is like the cheshire cat, soon there will only be a smile(y)!--Damorbel (talk) 05:41, 8 July 2009 (UTC)

Pure greenhouse effect not mentioned

Although the article (properly) says that absent the greenhouse effect, Earth's temperature would be around -17 deg C, it nowhere mentions that without the extensive climatic heat-dumping mechanisms of convection, evaporation, condensation, precipitation, and atmospheric circulation generally, the greenhouse effect would produce a temperature of around 70 deg C. Why not? -- Craig Goodrich 68.58.2.165 (talk) 19:43, 2 October 2009 (UTC)

Well, I suspect because this is an article on the greenhouse effect, and not on atmospheric dynamics, general circulation, and general climate. Also, do you have a reliable source for that claim? 70°C where? I suspect there are a number of simplifying assumptions in any calculation coming to that result... --Stephan Schulz (talk) 21:10, 2 October 2009 (UTC)

Do I understand you correctly Stephan, the Greenhouse Effect can be described without reference to "atmospheric dynamics, general circulation, and general climate"? I would agree that predicting a mean temperature of 70°C might prove a tad difficult but surely not much more challenging than the already massive 33°C increase generally attributed to the GHE.--Damorbel (talk) 19:22, 10 November 2009 (UTC)

The GHE can indeed be usefully described wihtout ref to atmos dynamics. However, does anyone have a clue what CG means by "...would produce a temperature of around 70 deg C", and a ref for it? William M. Connolley (talk) 21:07, 10 November 2009 (UTC)

I have struggled without success to find any explanation (or a ref.) for the GHE with the answer "+33°C" increase due to GHE radiation"; lots of assertions, hypotheses, probabilities etc. but no maths.

CG's "70 deg C" is just over double the highly improbable 33°C of the GHE when just a °C or so change is enough to start a hurricane, so why must he have a ref. for it? --Damorbel (talk) 21:41, 10 November 2009 (UTC)

We know, from repeated discussions, that you either don't understand or intentionally reject the widely accepted and fairly basic physics of the greenhouse effect. I'm not giving it another try. If he wants it in the article he needs to have a ref per WP:V. --Stephan Schulz (talk) 21:55, 10 November 2009 (UTC)

If you've struggled without success, you haven't looked too hard. Try http://en.wikipedia.org/w/index.php?title=Climate_model&oldid=24670575, the "Zero-dimensional models" (unfortunately some bozo has broken the current version) William M. Connolley (talk) 23:02, 10 November 2009 (UTC)

Thanks for the link. The relevants errors in this "explanation" are to be found in this quotation from your link:-

"It is possible to obtain a very simple model of the radiative equilibrium of the Earth by writing

$(1-a)S\pi r^{2}=4\pi r^{2}sT^{4}$

where

• the left hand side represents the incoming energy from the Sun
• the right hand side represents the outgoing energy from the Earth, calculated from the Stefan-Boltzmann law assuming a constant radiative temperature, T, that is to be found,

and

• S is the Solar constant - the incoming solar radiation per unit area - about 1367 Wm^-2* a is the Earth's average albedo, approximately 0.37 to 0.39
• r is Earth's radius - approximately 6.371×10⁶m
• π is well known, approximately 3.14159
• s is the Stefan-Boltzmann constant - approximately 5.67×10^-8 JK^-4m^-2s^-1

The constant πr² can be factored out, giving

$(1-a)S=4sT^{4}$"

Like all the other Greenhouse effect science your explanation is based on a false assumption... <snip - WMC> --Damorbel (talk) 12:51, 11 November 2009 (UTC)

The above is best read while listening to "Overture to a Holiday in Berlin" by the Mothers of Invention. Short Brigade Harvester Boris (talk) 13:15, 11 November 2009 (UTC)

DAM, we've read all that stuff before. Please don't repeat yourself. I posted that link on the off chance you hadn't seen it William M. Connolley (talk) 14:00, 11 November 2009 (UTC)

Yes William I hadn't seen your link but why delete my contribution? If it is as bad as you seem to think it will be ignored from its own (lack) of merit, but it isn't for you to judge that, do be so kind as to sustain the idea that the Earth radiates as a black body to support your formula $(1-a)S=4sT^{4}$. Otherwise you are just deleting a good contribution without reason, that's vandalism according to WIKI practice, don't you think?--Damorbel (talk) 15:47, 11 November 2009 (UTC)

I went through a long discussion on Damorbel's talk that hasn't received a reply, but I think that I have a really short version. The primary issue from what I remember is that Damorbel said there shouldn't be a frequency-dependence on albedo/emissivity. However, things have different colors, which is a clear indication that absorption and emission have a frequency-dependence. Awickert (talk) 19:13, 12 November 2009 (UTC)

Awickert, thanks for your comment but discussion of the weaknesses in the Greenhouse effect article become too difficult when serious contributions are removed [14] by editors who do not approve of/agree with them.--Damorbel (talk) 11:56, 16 November 2009 (UTC)

I did see that section; I don't have time to discuss anyway as (1) this is not my area of expertise so it takes extra effort on my part, and (2) I am very busy at the moment and for the forseeable future (the coming month). If at some point you would like to discuss, my talk is open, but I may not have time for a concerted discussion for some time, Awickert (talk) 01:44, 18 November 2009 (UTC)

Actually, when I originally posted the question above, the "70 C" figure was simply a remembered number from my Jr High School Earth Science course, ca. 1958 -- the greenhouse effect was well-understood and taught at the time, long before politicians got ahold of it. Given what is known about atmospheric composition, molecular spectra, radiation etc. I should think any of the prominent modelers should be able to give the theoretical magnitude of the effect off the top of their heads -- since all of this was equally well-known in the 1950s.

The most recent reference I find is in Dr Spencer's book Climate Confusion, pp 53ff, where he quotes the figure 140 deg F (=60 C), so either I may have misremembered or assumptions about average humidity (to which this estimate would be very sensitive) have changed.

In any case, it would appear that climatic processes (convection, hydrology, ...) serve to reduce the greenhouse effect by on the order of half, which is not particularly surprising since all weather is essentially moving heat and moisture from point A to point B. This would seem to indicate that climate feedbacks are strongly negative and stabilizing, rather than positive as Hansen's Venus-based models suppose. -- Craig Goodrich 68.224.132.157 (talk) 21:07, 22 December 2009 (UTC)

reducing radiation loss

"the atmospheric greenhouse effect however reduces radiation loss, not convection"

How does the greenhouse effect reduce radiation loss? The way I see it, it increase incident radiation (from the atmosphere), not reduce outgoing radiation. (Or am I missing something?) The atmosphere doesn't really reduce radiation loss from the earth as a whole either, since at "steady state" the energy lost will equal energy absorbed from the sun, which should be independent of the greenhouse effect (but affected by e.g. albedo). Saying the greenhouse effect "reduces radiation loss" might lead some to think of a reflective atmosphere. Although that might be the true in terms of clouds etc. it has little to do with the greenhouse effect directly.

There's a whole section explaining how the greenhouse effect works so reducing it into a potentially confusing one-liner feels unnecessary to me.
—Apis (talk) 07:33, 16 November 2009 (UTC)

Confused: are you saying you don't understand it, or are you exemplifying how this sentence could lead one to misunderstanding? I'll provide a useful response once I figure that out, Awickert (talk) 08:55, 16 November 2009 (UTC)

Hmm, I think it's an over simplification that is ambiguous and could lead to misunderstanding. And since the rest of the article does a good job at describing the greenhouse effect I feel it adds little information to the article.
—Apis (talk) 10:53, 16 November 2009 (UTC)

I mean, if you look at the illustration: [15], where is radiation loss reduction? That seems like a bad explanation. Heat from the surface (radiation, convection, latent heat) (and a little from the sun) is transferred to the atmosphere, the atmosphere gets warmer and because of it's temperature and emissivity it will radiate. some of that radiation is directed towards the surface of the earth, keeping it at a higher steady state temperature than it would have if it received only radiation from the sun.
—Apis (talk) 13:24, 16 November 2009 (UTC)

Apis' interpretation -- that the GHE is a second source of radiation, rather than a reduction of loss -- best reflects the physics of the atmosphere. See especially his second paragraph above. Short Brigade Harvester Boris (talk) 13:54, 16 November 2009 (UTC)

We know the Earth's surface is at 288K, warmer than deep space (2.75K). Taking the tropopause to be 250K and examining Apis' diagram [16], it does seem strange that there is only 195Wm² going to a place with a temperature 247^o colder and 324Wm² going from the Tropo. (250K) to a surface that is actually 38^o warmer than the tropo. and heating it (the surface) from 271K to 288K, i.e.17^o!--Damorbel (talk) 16:42, 16 November 2009 (UTC)

We know that you do not understand the difference between net heat flow and gross heat flow in open systems. No need to demonstrate this over and over again. --Stephan Schulz (talk) 22:22, 16 November 2009 (UTC)

"We know that you do not understand" yes Stephan of course you know that, the only problem is that this bit of physics is a pure Greenhouse effect invention, what is needed is a reliable source from showing how this is supported by thermodynamics. The idea that energy can be moved spontaneously against a temperature gradient is pure fantasy and against common experience. The idea is similar to that other Greenhouse effect fantasy - the Earth radiates in the infrared "like a black body", it's not so much that it's wrong, it cannot be shown to happen!--Damorbel (talk) 08:46, 17 November 2009 (UTC)

Pure invention? Fantasy? Well, it may be of interest for you to know that the whole theory of the Greenhouse effect and accompanying global warming is supported by both the American Physical Society [17] and the American Institute of Physics [18]. And, I reckon them folks got a pretty good handle on this whole physics thing.--CurtisSwain (talk) 10:41, 17 November 2009 (UTC)

Thank you Curtis for your contribution, it illustrate my argument perfectly. The links to the APS and AIP contain nothing to support the AGW/CO₂ hypothesis. The exposition I made above challenges the "institutional opininion" with a thoughtful analysis based on well established physics, it uses a a freely available diagram that illustrates a common explanation of the case for AGW. If you read what I have to say carefully you will see that the "common explanation for AGW" is in fact full of holes and does not make the slightest case for any warming effect by the so-called greenhouse gases. I t is a shame that most of my contribution has been edited or deleted, I can well understand that you think I don't know what I am talking about.

It is vitaly important that the weaknesses of any "catastrophy" scenario, have a mention in any encyclopedia if it is to retain its general credibility.

Your reliance on the publications of respectable institutions for making a scientific case baffles me completely. Such reliance would leave us with the idea that the Earth is flat, that the Sun revolves round the Earth and many more wacky ideas. It is fundamental to good science that conventional ideas, particularly those put forward by large institutions, are questioned rigorously.--Damorbel (talk) 07:17, 18 November 2009 (UTC)

Yes. In the scientific press. Wiki is not here to do science William M. Connolley (talk) 22:35, 29 November 2009 (UTC)

"Wiki is not here to do science". Wiki is a resource that should direct its users to good science. It is also guides users on current intellectual matters, as such it is important that the weaknesses in the "Greenhouse effect" are made clear where they conflict with established physics. William, it seems that you believe a planet can simultaneously have an albedo and behave like a black body, a mathematical construction saying that incident light (or EM energy) is not reflected by a black body. The formula you use (and many with the same idea) is the mathematical representation of your belief. Now the Greenhouse effect article is centred on this belief; so it is quite appropriate in an encyclopedia article to make reference to this weakness. The fact that the belief is shared by many is no reason to eliminate reference to perfectly good science that questions the credibility of the Greenhouse effect concept. The idea that respectable institutions such as American Physical Society and American Institute of Physics have published statements supporting the concept is not a scientific argument that should convince you or anybody else. I asked you for substantiation of the connection between the black body model and the greenhouse effect and all you offer are statements made by respectable institutions, is that your idea of science? I had no idea that this kind of "stuff" was the basis of the Greenhouse effect, I think it is time to take a closer look at a concept that relies on free energy and perpetual motion machines because, if you were familiar with thermodynamics, you would soon realise that this is the unfortunate path your argument follows! --Damorbel (talk) 11:05, 24 December 2009 (UTC)

If your interpretation of physics differs from that off all major National Academies of Science, a whole lot of other scientific bodies, and the vast majority of published literature from textbooks via reference works to current scientific articles, there are two possibilities. Either they are all wrong, or we see a single case of Dunning–Kruger effect. --Stephan Schulz (talk) 09:32, 25 December 2009 (UTC)

Erm, Stephan, didn't you notice what I said? "The links to the APS and AIP contain nothing to support the AGW/CO₂ hypothesis". I have the impression that you take the words of these institutions as defining the rightness of the science. They are then, in your eyes, the guarantors of the "truth". Have you any scientific training? Is this what your teachers told you? Do you teach? Do you reccommend this as a method of disseminating knowledge and making progress? You seem to have a rather desperate wish that "No questions be asked of your belief", is this not what the Dunning–Kruger effect is all about? I only asked for a reliable source for the inconsistencies in Apis' diagram [19] and what I get is the Media and Government Relations Division of the IPL, I think something better is needed.

Perhaps you have not noticed that self-important scientists and their institutions have a long history of suppressing good science, e.g. Humphry Davy. --Damorbel (talk) 08:38, 30 December 2009 (UTC)

What is the Greenhouse Effect and how does it act on the Earth?

(essay removed)

I've removed the rather lengthy unsourced essay. This page is for discussion of the article.

The essay was previously removed from the article, it is again an essay, no references provided and duplicative of existing content. It's in the history for those interested. Vsmith (talk) 13:40, 30 December 2009 (UTC)

REPLY: This is a geology article that explain clearly and simply what is the Greenhouse effect. There isn’t duplicative or existing content but a simple and complete information about Greenhouse Effect. Now I sign it and I post it below for discussion:

"The Greenhouse effect is the capacity of the atmosphere to retain more or less heat. The Greenhouse effect isn’t always the same. In fact, a more humid atmosphere (with higher content of water vapor) trap more heat than less humid atmosphere; an atmosphere that contains more carbon dioxide or methane, retains more heat than the atmosphere with less content of these gases. When we speak about an increase or decrease of the Greenhouse effect, we refers to the increase or decrease of atmosphere capacity to retain heat: it is obvious that if the atmosphere is able to trap more heat there will be a temperature increase, if the atmosphere is able to trap less heat there will be a temperature decrease.

However, the Greenhouse effect shouldn’t be confused with the simple increase or decrease of the temperature. It isn’t certain that an increase or decrease of the Earth temperature is due to the Greenhouse effect variation: for example when in the past the Sun delivered to Earth more energy, it cause a temperature increase but without necessarily a Greenhouse effect’s change. In this case the atmosphere’s capacity to retain heat didn’t change and the temperature increase is only due to more energy from the Sun, that is came into the Earth's climate system.

Many factors contribute to increase or decrease the Greenhouse effect. Some are internal to the atmosphere (rain, movement of air masses, clouds, water vapor content, carbon dioxide, methane, ...), the others are external (seas’evaporation, carbon dioxide exchange between sea and atmosphere, vegetable and animal’s respiration, bacterial action in the soils, volcanic emissions, ...).

In situation of ideal thermal equilibrium (more energy is absorbed and more is returned), all these factors take part together, some increase the Greenhouse effect, some decrease: the variations cancel each other, keeping the system in a thermal equilibrium. However, the climate system always live in a greater or lesser alteration of its thermal equilibrium: more or less local rain and clouds, high and low pressure fields, evaporation, ... are all phenomena which constantly change the Greenhouse effect on more or less wide area. However in a global view, all these changes cancel each other and keep constant the capacity to retain heat.

The increase or decrease of Greenhouse effect is the tendency, of all these factors without exceptions, to find a balance between them towards a situation of higher or lower temperature. The Greenhouse effect is a rebalancing component of the climate, acting on local area, it is continuously changed on more or less wide area, but it gives a global equilibrium. Just the thermal global equilibrium cancels the changes in local area and the compensations of changes in local area (some positive, others negative) are able to keep a global equilibrium.

The greenhouse effect avoid the Earth system enters into a thermal disequilibrium. When a factor tends to increase the Greenhouse effect, the climate system reacts with cooling effects. When the Greenhouse effect tends to decrease we’ll have heating effects: changing a parameter that unbalance the climate system (solar radiation, evaporation, rain and clouds, activities of plants, animal or bacterial, volcanic activity, greenhouse gas content, ...) the system reacts rebalancing the climate change as locally (faster) as globally (more slowly). If a factor increases the Greenhouse effect (higher content of water vapor or Carbon dioxide, ...), the system will change developing elements that balance the climate system (increase of atmospheric perturbation that release water vapor in the air, greater plant’s development that uses water and carbon dioxide, ...).

The factors that influence the Greenhouse effect are many (some still not well known) and they act differently. Some are narrow phenomena (rainfall, evaporation, wind, clouds, ...). Others have a grater global effect (high or low pressure fields, the movements of air masses, changes in the atmospheric global contents of water vapor, carbon dioxide or methane, ocean currents , ...). some causing changes in short-term (hours, days, weeks) and other in long-term (years, decades, centuries, ...):

1. The evaporation’s increase causes a heating effect: the atmosphere becomes more humid (it increase the water vapor content) and the more humid atmosphere retains more heat;
2. the rainfall increase causes a cooling effect: the atmosphere becomes less humid (losing water vapor) and retains less heat.
3. The cloudiness increasing has a double effect: mainly have a cooling effect by isolating the surface from sun’s rays ( less radiation comes to the earth's surface from the sun, less heat comes into the Earth), in other cases has a heating effect blocking heat radiation from the atmosphere (like a cork).
4. The high and low pressure fields set the movements of warmer or colder air (more or less humid) and they act directly and quickly on the capacity to retain more or less heat from the atmosphere.
5. Movements of air masses, cyclones, ... are strongly connected to what has been said about the rain, clouds, and fields of high or low pressure.
6. Ocean currents play a very important role to rebalance the climate system, same to the air masses movements in the atmosphere.
7. The atmospheric variation of water vapor, carbon dioxide and methane, cause more long-term temperature change and they are balanced by the Greenhouse effect because it’s strongly associated with seas variations and biology variations, such as:
   1. Carbon dioxide plant respiration (the more carbon dioxide = the more plant respiration)
   2. the interchange between atmosphere and oceans of water vapor or carbon dioxide (the more heat = the more interchange of water vapor or carbon dioxide between atmosphere and oceans; but the more water vapor there is in the atmosphere and the more rainfall en clouds we have)
   3. the interchange of methane between land and atmosphere caused by bacteria (the more heat we have the more methane is released into the atmosphere)." —Preceding unsigned comment added by Chicco3 (talk • contribs) 10:45, 30 December 2009 (UTC) --Chicco3 (talk) 12:26, 31 December 2009 (UTC)

MeSSAGE: If there isn't any problem can I add this geology article ? —Preceding unsigned comment added by Chicco3 (talk • contribs) 17:32, 8 January 2010 (UTC)

Sotty, but there are many problems. Parts are wrong, parts are confusing, and parts don't belong here. Do you have a source for this article? --Stephan Schulz (talk) 18:40, 8 January 2010 (UTC)

REPLY: This is my geology italian article (based in many books of geology "Geologia ambientale", "Clima e natura",...") if there are language wrongs or confusing parts, please correct them. Thanks —Preceding unsigned comment added by Chicco3 (talk • contribs) 10:35, 9 January 2010 (UTC)

Rv: why

I removed the assertion that the GHE is natural [20]. Clearly, the reason we're all intersted is because it is at least in part not natural William M. Connolley (talk) 14:04, 7 February 2010 (UTC)

A natural process that has been "corrupted" by supernatural powers. --- sorry, couldn't resist (the ***** made me do it). Vsmith (talk) 14:54, 7 February 2010 (UTC)

As the natural bit has been re-instated, I'll chime in in support. It is a natural process. The part some of us are "interested in" is covered quite well in the section Enhanced greenhouse effect. Vsmith (talk) 18:36, 8 February 2010 (UTC)

I think it has gone again now. We're back to the status quo ante - say neither - which seems best to me William M. Connolley (talk) 22:10, 8 February 2010 (UTC)

Yeah Nigelj's edit was good. Don't really need to emphasize the natural bit, although that's what some want. Why isn't this article on the probation list? Vsmith (talk) 22:40, 8 February 2010 (UTC)

It seems to me the natural part is adequately covered in the section about black body radiation that explains how much colder it would be without the GHE. JPatterson (talk) 19:26, 9 February 2010 (UTC)

Well, this one is largely about science so we haven't bothered eedit war over it :-) William M. Connolley (talk) 22:55, 8 February 2010 (UTC)

Aren't most about the science? Anyway, added the probation note as our "natural" friend has been warned about it. Vsmith (talk) 02:55, 9 February 2010 (UTC)

Hi, There was some confusion about the term "natural": the heating of earth's surface is part natural and part human, and maybe the increase of Greenhouse effect is not natural,... but the greenhouse effect is obviusly only natural. I added the term "natural" to make this clear. Chicco3 (talk) 20:55, 10 February 2010 (UTC)

Greenhouse gases section

I would like to see a sentence explaining the ranges. Do these represent different estimates or some sort of functional dependence on some other parameter? In other words, is C02's effect somewhere between 9% and 26% because we don't know exactly or does it vary between that range dependent on other factors? JPatterson (talk) 23:37, 8 February 2010 (UTC)

I just noticed this comment, so I apologise for the late response and hope it's still useful. The issue is a semantic one -- since there is overlap between CO2 and other greenhouse gases, it's difficult to define the exact contribution. If you remove everything but CO2, you still get about 26% of the greenhouse effect. If you only remove CO2, it drops by about 9%. StuartH (talk) 03:17, 20 March 2010 (UTC)

'Basic mechanism' edit

I reverted the edit by Nigelj because he has made no attempt to justify it. His edit is confused and unhelpful. If User:Nigelj wants to edit someone elses work let User:Nigelj start here with an explanation of what is needed.--Damorbel (talk) 19:30, 10 February 2010 (UTC)

Hi Damorbel. Which part of my edit do you disagree with? I don't believe it can be all of it because it has so many aspects. I have already tried to explain some WP policies and guidelines to you on my talk page so we won't go into it all again here. Just to say that from what I see, your contribution to that section was quite small, so even if you feel that you own those phrases, you should have no problem with my changes outside of that sentence. Am I right? (I'm still guessing what the actual problem is here) --Nigelj (talk) 20:36, 10 February 2010 (UTC)

Nigelj, in the context of your changes, both Earth and Sun are proper names that should be capitalized. Damorbel, you should at least restore the spelling and grammar fixes that Nigelj made. Q Science (talk) 21:28, 10 February 2010 (UTC)

I made the simple fixes. However, this section still needs work. Q Science (talk) 21:46, 10 February 2010 (UTC)

Only in US English are they, and at the moment the article is an inconsistent mix of the two ( both legitimate) conventions. Also is 'Idealized greenhouse model' a proper noun too? And why is that now linked twice in adjacent paragraphs? --Nigelj (talk) 21:50, 10 February 2010 (UTC)

Well, these articles are "typically" in US English. I left the alternate spelling of "vapor" when it was in paper titles. I left Idealized greenhouse model capitalized because it is an article title, but that may not be a valid reason. Typically, I would capitalize all 3 words in this case, but that is the style "I" follow and not from some standard. I have no problem with multiple links in large articles, but I agree that adjacent paragraphs is too frequent. Please don't read my changes as the only ones I agree with, but as the ones the must be made. Q Science (talk) 00:20, 11 February 2010 (UTC)

Thermal radiation from gases produces an omnidirectional field, this should be clear in the article. I improved WMC's revision which implied that radiation from GHS was only downwards. Any picture of the Earth in the infrared will show the GHGs glowing brightly, i.e. they are the principle way the Earth is cooled. This should be made clear in the article, your editing eliminated this .--Damorbel (talk) 21:44, 10 February 2010 (UTC)

You're going to have to be more specific as to article wording I'm afraid. I'm perfectly aware of the physics of what you're saying and I clarified it elsewhere in the article yesterday too, despite JPat breaking that bit again today. As to your reversion, which part of "a layer of atmosphere with greenhouses gases will absorb heat being radiated upwards from lower layers, and re-radiate it in all directions, both upwards and downwards" (my words) is worse than "a layer of atmosphere with greenhouses gases will radiate heat in all directions, both upwards and downwards" (your words)? In the next sentence I made it even clearer by saying "In order to achieve thermal equilibrium, this results in a warmer surface below, in order still to radiate enough heat back out into deep space from the upper layers". I don't see how you can be finding fault with the physics of that. Please explain, in terms of article wording (not a new or separate explanation of things I'm sure we both understand.) --Nigelj (talk) 22:01, 10 February 2010 (UTC)

Nigel, the problem with your physics is that a gas like CO2 absorbs heat from a warmer source (2nd Law) e.g. the Earth's surface, and tranfers some of the heat by radiation to a cooler sink. The cooler sink may be deep space or an adjacent layer, normally higher up. Let us agree on the physics first and then sort out the wording later, OK? I will check the article to see if it is not necessary to mention the fundamental mechanism at this point. --Damorbel (talk) 10:21, 11 February 2010 (UTC)

'My' physics is the same as 'your' physics, as far as I can see. None of what you mention here was in this sentence in the article, nor was it altered by my edit. How long is this going to take? We still have other problems in this section that you reverted for no reason, and that Q Science has only partially fixed. It doesn't really matter (it's only a Wikipedia article after all), but this seems to be getting a bit laborious now over very little. --Nigelj (talk) 12:34, 11 February 2010 (UTC)

If you both agree on the my/your physics, then, since you're both wrong, you both need to step aside so those who understand the process make the wording changes. Specifically, molecules of CO2, or any greenhouse gas that can accept EM power from the IR field they are bathed, will accept energy quanta (then transferring- or perhaps not- the energy to neighboring N2 and O2), provided the molecules are in a state that allows the corresponding energy transfers, no matter where the IR radiation originated (above or below, in altitude, the receiving level) and no matter what the relative temperatures are. That is is the heating up process. The cooling down side of the process also occurs when the steps are reversed. The relative rates determine the direction of temperature change. This explanation does not violate any law of physics. It may be an "inconvenient truth" to some, and an "incomprehensible truth" to others. blackcloak (talk) 05:59, 2 March 2010 (UTC)

Have you checked the Idealized greenhouse model? The link appears in the pargraph. It is very poor, weird statements like "much cooler and so radiates heat back away from itself at much longer wavelengths," I'll accept the current version of the Greenhouse effect for the present but with this idealized greenhouse model the picture is just becoming blurred, there is no reason to have an extra like the Idealized Greenhouse model.--Damorbel (talk) 21:34, 11 February 2010 (UTC)

So, what is the state of this discussion now? I intend to tidy up that section again soon. Blackcloak, I can assure you that there is no need to go into quantum mechanics to explain the greenhouse effect at this level, nor to bring in conduction between CO2, N2 and O2 within the atmosphere.

I didn't use the term quantum mechanics. If "at this level" is your true motivation, then let's just say up front that this is an oversimplified explanation of a complicated subject and has been deliberately watered down so a 12 year old can understand most of it. As for conduction, where is 99% of the retained atmospheric heat (all sources) stored? If you can answer that question correctly, how did it get there, and how does it leave? But I do understand your point- why would anyone ever choose to read through a whole lot of extraneous material just to understand a simple concept. blackcloak (talk) 22:23, 11 March 2010 (UTC)

Damorbel, I have read it and made some contributions there as well. Now, on the subject of specific article wording suggestions, you have both been utterly mute, so I will list the reasons why I intend to make each change, then make it unless you can come up with better specific wording. Please have a look at WP:TPG to see why that preamble points are important.

I'm talking about the two paragraphs that make up the section 'Basic mechanism'

1. Capitalisation and linking I understand that some people are American and so will insist on capitalising sun and earth whatever happens, so I will give up on that. 'Idealized greenhouse model', however does not need capitalising when it appears mid-sentence and it only needs wikilinking the first time it appears in this section.

   Actually, the Wikipedia style guide specifically says that Sun and Earth should be capitalized. Q Science (talk) 06:10, 11 March 2010 (UTC)

2. Water becomes less I propose to replace "largely because the atmosphere is drier and water vapor - an important greenhouse gas - becomes less" with "largely because the atmosphere is drier there and water vapor is an important greenhouse gas". This is clearer without the parenthetic form and without repeating a synonym for 'drier'.

   Is the word "concentration" too complicated for you to consider? blackcloak (talk) 22:23, 11 March 2010 (UTC)

3. Presentation becomes reasonable I want to replace "the presentation of the Idealized greenhouse model becomes more reasonable" with "the description given by the idealized greenhouse model becomes more realistic". This is because the words I propose mean what we are trying to say, but the words presentation and reasonable are slightly the wrong ones IMHO.
4. Absorb then re-radiate I want to clarify "a layer of atmosphere with greenhouses gases will radiate heat in all directions, both upwards and downwards" by adding something about having to absorb the heat first before re-radiating it: "a layer of atmosphere with greenhouses gases will absorb heat, mostly being radiated upwards from lower layers, and re-radiate it in all directions both upwards and downwards".

   "a layer" does not absorb heat, the greenhouse gases do. How about, for part of this, just say- The greenhouse gas component of the atmosphere at any altitude absorbs heat energy arriving from all directions, and re-radiates heat energy in all directions. And then add something like- Any change in temperature at any one point in the atmosphere due to the inflow and outflow of heat energy is proportional to the net change in the heat energy at that point. "all directions" and "updownwards and downwards" is kinda redundunt (sorry, couldn't resist). And what do you mean by absorbing before re-radiating. This is not correct. The physics does not say this, and any author who does is just another source, even if properly referenced, of hogwash. That situation can only occur at absolute zero. blackcloak (talk) 22:23, 11 March 2010 (UTC)

   This of course assumes that convection, evaporation, and rain do not exits. It also ignores the fact that clear nights are colder than cloudy nights. Q Science (talk) 06:03, 11 March 2010 (UTC)

   I included the words "due to the inflow and outflow of heat energy" for these reasons, and used N's simplified way of referring to electromagnetic IR radiation. I chose not to instigate a confrontation over proper technical terminology. Afterall N has made it clear that there is no place in this article for terms like quantum mechanics. blackcloak (talk) 08:26, 12 March 2010 (UTC)

5. Deep space at 2.7 K There is no need to mention the temperature of deep space in the next phrase - the greenhouse effect would work in the same fashion whatever its value. Therefore I want to change "thereby warming the surface and simultaneously cooling the atmosphere by transmitting heat to deep space at 2.7K" to "In order to achieve thermal equilibrium, this results in a warmer surface below, while radiating enough heat back out into deep space from the upper layers." It is the point where the warming is actually explained: the amount of greenhouse warming is calculated by setting total heat lost equal to total heat received, and saying that whatever had to be radiated upwards from the greenhouse layers to achieve that was also radiated downwards and so is added to the radiation received at the surface. Leaving that out and replacing it with a diversion about 2.7 K was a missed opportunity.
6. Increasing the concentration presently "increases the amount of radiation, and thereby warms the surface more". I suggest "increases the amount of absorption and re-radiation, and thereby leads to a still warmer surface". This reinforces the point made above, that the greenhouse layers are in thermal equilibrium, absorbing and re-radiating heat.

   "thereby leads to" is a nonsequitur. Beyond that it's wrong. At night it leads to a cooler surface. You have to put in the words like, net power or energy movement and averaging over very long time periods in order qualify words like equilibrium. In point of fact, the atmosphere is never at thermal equilibrium. That term can only be used to describe a long time average. blackcloak (talk) 22:23, 11 March 2010 (UTC)

Now, while you preview these changes, remember that I have made all these changes before and that Damorbel reverted all of them, accusing me of "destroying an edit of mine in the process. You made no contribution in the talk pages on this, any particular reason. Wikipedia contributors should always respect and explain, you have done neither. I think respect and explain is an excellent policy, do you?" on my Talk page.

I am happy to work with suggestions for even better improvements than the ones I have proposed here, but I am not going to discuss every aspect of thermodynamics with all-comers. If you have a better wording suggestion, please make it here, and nothing else. I want to get on; this set of edits is only part of the story as we have no mention of higher and lower frequency IR radiation in here yet, and I believe that is important enough for inclusion too, after these fixes are in place. --Nigelj (talk) 21:09, 10 March 2010 (UTC)

I don't care about the caps but your version is clearly better. The stuff about 2.7 K is distracting, and other bits were wrong William M. Connolley (talk) 22:23, 10 March 2010 (UTC)

Saying that the "concentration" of CO2 is increasing is technically correct. However, it is the "mixing ratio" that has increased from 300 ppm to 380 ppm, not the "concentration" (moles per liter). The concentration changes with height, as the pressure goes down so does the concentration. However, the CO2 mixing ratio does not change with height until above 84km. Q Science (talk) 09:01, 12 March 2010 (UTC)

You are correct within the limited scope of your usage of the term "concentration". Check out the sections titled "Qualitative definition" and "Mass versus volume". Note the STP default definition. Also note that Wikipedia seems to define "mixing ratio" only in the context of water vapor. One of the ways pseudoscience develops is by the non-standard usage of terms. blackcloak (talk) 22:06, 12 March 2010 (UTC)

'Basic mechanism' edit /2

What a mess has been made of this description! It is now mumbling and incoherent. What on earth does "Within the region where radiative effects are important the description given by the idealized greenhouse model becomes realistic" mean? Important - what - in social circles? And is there anything clear about "this results in a warmer surface below, in order still to radiate enough heat back out into deep space from the upper layers. Increasing the concentration of the gases increases the amount of absorption and re-radiation, and thereby leads to a still warmer surface.[7]"? If this is the best explanation that Greenhouse effect apologists can manage? It is little wonder that the general public are increasingly doubtful about the whole matter. I don't think you guys have a clue what you are talking about.

Some time ago I pointed out that the radiation field from greenhouse gases is omnidirectional, this doesn't appear any more, no discussion, no explanation, no wonder there is nothing but meaningless twaddle here.--Damorbel (talk) 20:39, 19 March 2010 (UTC)

I second that. The "Basic mechanism" section is terrible and pretty much incomprehensible. The picture is also not good. IMO the article should be flagged by an administrator until this is fixed. 140.160.160.52 (talk) —Preceding undated comment added 00:30, 22 March 2010 (UTC).

Explanation of numbers on File:Greenhouse_Effect.svg

(I was about to pose this question in the talk page for the image, but there were indications that that's not the wisest place to do so.) In that file's page's text, it explains the 235 W/m², and gives some other ratios and such. Could someone explain here or elsewhere where the rest of the numbers in the diagram come from? I see that 67 (radiation received by the earth) + 168 (radiation received by the atmosphere) = 235 (radiation delivered by the sun). 40 (lost by the earth, bypassing air) + 452 (radiated back to the air) = 492 ("Heat and energy in the atmosphere") = 324 (retaken by the earth) + 195 (released into space) - 27 (what?). And what's the number "Greenhouse gas absorption: 350" for?

Evidently, at least one of these numbers is incorrect, right? Is the Greenhouse gas value worth mentioning (how are greenhouse gases different from any other gases that keep heat in earth's system)? What's the significance of that value of 350? It seems out of place to me. What am I missing here? —Preceding unsigned comment added by D. F. Schmidt (talk • contribs) 16:54, 14 March 2010 (UTC)

You've got 67 and 168 the wrong way round, but that doesn't matter. For the Earths sfc, from those numbers, 452+40 = 492 and 168+324 = 492 so that all fits. 324+195 = 519 = *atmos* loss. Atmos gain = 67+452 = 519, so that balances too. Solution: you've balanced the wrong numbers William M. Connolley (talk) 22:25, 14 March 2010 (UTC)

The "452 (radiated back to the air)" is actually

• 24 thermals (basically a guess, used to balance the equations)
• 78 evaporation
• 350 surface radiation - assumed to be absorbed by greenhouse gases. However, perhaps 50% is actually absorbed by clouds.

Earth's Annual Global Mean Energy Budget, Kiehl and Trenberth (1997), Bull. Amer. Meteor. Soc., 78, 197-208. Q Science (talk) 05:25, 20 March 2010 (UTC)

Important Omission

Williams rework does not include the important fact that GHGs emit in all directions. --Damorbel (talk) 15:36, 5 February 2010 (UTC)

Isn't that obvious? You get it from the idealised model page, anyway William M. Connolley (talk) 20:40, 5 February 2010 (UTC)

"Isn't that obvious?" Clearly not, without it the uninformed reader might easily take the assertion that "a layer of atmosphere with greenhouses gases will radiate heat downwards" meant that downwards was the only direction of radiation. --Damorbel (talk) 15:27, 7 February 2010 (UTC)

Feel free to add "up and" (being a layer it can't sideways, of course) William M. Connolley (talk) 17:14, 7 February 2010 (UTC)

"Feel free to add "up and"" Er, thanks for the advice WMC but it is my contribution. The way it is written makes it clearer than your suggestion, thank you.--Damorbel (talk) 10:31, 8 February 2010 (UTC)

Pardon my ignorance, but please explain why being a layer precludes it from radiating sideways. If you put a wrought-iron frying pan on the stove to cook pancakes, the handle also gets hot, not just the part of the pan immediately above the burner. Why should this be any different? D. F. Schmidt (talk) 16:06, 14 March 2010 (UTC)

The atmosphere is not far from being spherically symmetrical with no large temperature gradients in the East/West axis so little heat tranfer in this direction. There is a larger temperature gradient from the equator to the poles (35K-70K over 10^4km?) so some transfer here. At the top of the homosphere (85km thick) there is the mesopause, here the temperature is about 190K so the temperature gradient is in the region of 1K/km, about 1000 times greater than that from the equator to the poles.--Damorbel (talk) 19:55, 19 March 2010 (UTC)

Then "up and down but not sideways" is a horrible way to convey that meaning. "North and south but not east and west" is more meaningful and representative of what you mean. D. F. Schmidt (talk) 04:40, 23 March 2010 (UTC)

Scratch that. I misread. D. F. Schmidt (talk) 04:43, 23 March 2010 (UTC)

Major Error in Comparison of Earth without atmosphere and Earth with Atmosphere

There is a glaring and obvious error in second paragraph. To support the idea that the earth would be -18 or -19 degrees Celsius, the contributor claims that "Earth's surface reflects about 28% of incoming sunlight," referencing the "Introduction to atmospheric chemistry" text. The problem with that citation is that the 28% value includes clouds [which reflect the lion's share of that number]. The Earth's surface albedo is much less [4% is a standard figure]. Without an atmosphere, there would be no clouds...so this becomes a false comparison. —Preceding unsigned comment added by 76.104.101.94 (talk) 18:44, 19 March 2010 (UTC)

There is room for improvement there, I might have a go at it now, but the earth "without a greenhouse effect" is what is actually mentioned, and is a fair comparison. You're right about the surface and clouds, though. StuartH (talk) 03:10, 20 March 2010 (UTC)

Is my edit satisfactory? You're right that it's not all the surface, so just saying the "Earth reflects" is accurate. StuartH (talk) 03:19, 20 March 2010 (UTC)

The problem here is that the "5 degree" value is arrived at by considering the Earth as a radiative blackbody, and then a number is simply fiddled with in an effort to accommodate the clouds, but that is not the same thing as "the Earth without the greenhouse effect." For example, the "Earth without the greenhouse effect" would still lose energy through heat flux and convection, would be shielded by both clouds AND the atmosphere, etc. In other words, the formula from which the 5 degree value is obtained is not a formula that really matches the fantasy condition of starting with Earth and simply removing "The greenhouse effect." In fact the oft-quoted "-18" and "-19" degree values are contrived and have no real meaning. They ask people to pretend gases are their in one capacity and not another. If there were no greenhouse effect, it would mean no water vapor in the atmosphere [other wise you are talking about a fanciful universe where water vapor does not act like water vapor], and if there is no water vapor in the atmosphere, no clouds can exist. It's just a meaningless statement to say what would happen "without the greenhouse effect." It is far more meaningful to say what the Earth would be like "without an atmosphere."

To put a fine point on this, take a look at one of the sources for that statistic: http://eesc.columbia.edu/courses/ees/climate/lectures/radiation/ . If you scroll down to where they get their value [-18], the actually say: "We have added a subscript e to the temperature to emphasize that this would be the temperature at the surface of the planet if it had no atmosphere." But this has no basis in reality because they obtain their value for the effective temperature [-18 degrees] by plugging in the albedo due to clouds. Obviously considering the earth "without an atmosphere" would mean not having clouds. This -18 number is a mix-and-match statistic with no meaning.

If the earth truly had no atmosphere, it would be more like -50 degrees C [the mean temperature of the Moon], but this would not be its BLACKBODY temperature...which brings up another major problem any of this: you cannot use the blackbody temperature as a proxy for "mean temperature" for a planet that has no atmosphere. Due to the T^4 dependency on radiation, the mean temperature is very different from the blackbody temperature. [In the case of a planet about as far away from the Sun as the Earth is, that difference is about 50K !] —Preceding unsigned comment added by 76.104.101.94 (talk) 06:54, 24 March 2010 (UTC)

Sorry to pile on...but I realized a more clear problem here. Without "the greenhouse effect" [i.e. gases in our atmosphere absorbing radiative energy], we would probably not have clouds at all, even if there were enough water vapor in the atmosphere to sustain oceans, etc. Without the greenhouse effect, the atmosphere would, of course, be completely different (and much, much colder). This is another reason why it makes no sense to use the Earth's "Albedo with Clouds" in a description of what the temperature would be like without the greenhouse effect. You are instantiating a parameter from one model into the other when the changes in the model would affect the parameter itself.76.104.101.94 (talk) 19:07, 24 March 2010 (UTC)

The numbers are relevant and useful as an introduction to the greenhouse effect, but it's important they be presented as accurately as possible. It should not be understood as an earth "without an atmosphere" or "without greenhouse gases", which is why it is stated as "without a greenhouse effect", but it does ignore cloud and ice albedo feedbacks. The talk page is about improving the article, after all, so if you have a better phrasing for the numbers presented, it will be given due consideration. Perhaps a name other than "mean temperature" for the -19 degree calculation, or a calculation of the effective blackbody temperature of the surface (e.g. a mean temperature with a T^4 weighting or something similar) for a more valid comparison with the full blackbody temperature would be appropriate. On the other hand, with the earth's much greater rate of rotation and the heat capacity and heat redistribution capability of the oceans, I don't think the moon is a better "no greenhouse" model. StuartH (talk) 11:59, 30 March 2010 (UTC)

Maximizing Solar Heat Gain

beginning

This article on the greenhouse effects makes the claim that there are two greenhouse effects: one inside a building called a greenhouse and one outside the building called a greenhouse in a place called an atmosphere. For that claim to stand, we have to assume that all literature on the atmospheric greenhouse effect has resorted to a misnomer by calling it a greenhouse effect, since they are supposedly not the same thing. I would like to see evidence of this implied global mistake, as well as some proof showing that the definition of the greenhouse effect is not under dispute. If this cannot be demonstrated, then it is an assertion and should be called out as such or edited out.

Regarding the claim that the greenhouse effect inside a building is due to a lack of convection, this is not based on the design of actual greenhouse buildings. Many greenhouse buildings are deliberately designed for forced or natural convection[2,3]. Recommended air flow for the inside of a professionally built, commercially available greenhouse building is about 1 m/s [1]. This airflow is designed to regulate temperature and humidity, therefore the airflow can occur in the form of outside air ventilation, and/or inside-only air distribution[4].

In light of these facts, a redefinition of the greenhouse effect is in order, but redefining the greenhouse effect for buildings being due to "a lack of or the minimization of convection" instead of "no convection" or "suppressed convection" will now create a new problem since the exact rate of flow at which point the greenhouse disappears or goes away has never been defined and agreed upon in scientific literature. Also, in order for convection to be suppressed, the distance between the glass/plastic panels and the ground would have to be less than two inches, as has been demonstrated for convection cells in double-glass window panels[5].

No single experiment is ever valid unless it has been reproduced by others using the same prescribed techniques, but that is exactly what the Wood's experiment is -- a single experiment that has never been reproduced. As if that wasn't enough, there is a huge problem with the Wood's experiment, namely that it does not attempt to reproduce the conditions inside of an actual greenhouse, such as high humidity and natural or forced convection. What Wood attempted to reproduce was an oven, not a greenhouse. The Wood's experiment is clearly not a scientifically valid experiment and cannot be used to support any claim.

When designing buildings, architects attempt to minimize solar heat gain. This is the opposite of the greenhouse effect, which is to optimize or maximize solar heat gain. Any definition of the greenhouse effect should include the concept of solar heat gain. For maximum solar heat gain, you would want to keep natural convection rates high during the heating cycle -- not suppress them[6]. Only at night would you want to suppress convection in order to keep temperatures and humidity high.

[1] http://www.ces.ncsu.edu/depts/hort/greenhouse_veg/topics/gtp_pages/relhumidity.html

[2] http://cat.inist.fr/?aModele=afficheN&cpsidt=14372166. This also explains why a typical greenhouse has a sloped instead of a flat ceiling, e.g. -- to encourage convection, not suppress it.

[3] http://www.greenhouses-etc.net/ghse-fw/grnhouse_construction.htm. Here we see vents supplied with a greenhouse to deliberately induce convection, yet it does not destroy the greenhouse effect.

[4] http://www.docstoc.com/docs/20542896/Greenhouse-Heating-and-Ventilation-Systems

[5] http://en.wikipedia.org/wiki/Insulated_glazing

[6] http://www.emt-india.net/ECBC/EnergyEfficiencyinHospitals_4Mar2009/Tips/GlazingDesignandSelectionGuide.pdf

HY1802D (talk) 02:00, 20 March 2010 (UTC)

The comparison between the so-called greenhouse effect and a real greenhouse is entirely spurious. The 'Greenhouse effect' explanation tries to make connection between a popular way of keeping a relatively small volume warm and a supposed global warming effect caused by the fact that some gases (the so called Greenhouse gases) absorb and emit radiation by thermal interactions (collisions, vibrations and rotations). Greenhouses are warmed and cooled by this mechanism also but the air inside them (when the windows are closed) does not take part in the general circulation of the atmosphere which, to a considerable extent, is driven by convection thus the heat from sunlight arriving during daylight hours is kept local (trapped?) by the glass walls. Yes, convection is important for heat distribution inside a real greenhouse, also it is important for keeping the world outside the greenhouse reasonably cool in sunlit conditions, it is in this sense that real greenhouses suppress convection.

The Greenhouse effect that is supposed to have climate changing properties is said to arise from the fact that the GHGs are warmed by absorbing radiation in the infrared; it is then said that they tranfer heat back to the surface because GHGs also radiate in the infrared. This latter assertion is completely at variance with the second law of thermodynamics because the surface, globally speaking, is always warmer than the atmosphere and heat transfer is always from warmer places to cooler.

Further, most explanations of the greenhouse effect show a higher level of radiation [21] from the GHGs to the surface that to outer space, this is at variation with the known characteristics of radiation from gases which is omnidirectional. What is worse, in the same diagram [22] GHGs are shown emitting levels of radiation that could only be achieved by a blackbody, this attribution of blackbody properties to a low density gas is quite absurd. --Damorbel (talk) 08:15, 20 March 2010 (UTC)

While you may disagree with the numbers in the chart, do you at least agree that they are consistent? Outflow into space equals inflow from space (the sun). Inflow to the atmosphere equals outflow from the atmosphere. Inflow to the surface equals outflow from the surface. Do you believe that they have to be consistent, or are you willing to tolerate an inbalance? If you believe they are consistent (and should be) but the numbers are wrong, tell us which one/s is/are wrong, guess or choose a reasonable amount, and then tell us how you balance the net flows. Until you provide us with a cogent alternative, there's no way any knowledgeable person will ever take you seriously. As for me, I think the chart is probably fairly accurate and we can safely use it as a good starting point. Elsewhere I notice you are now using the term "globally speaking" in a sense that might be implying NET heat flow (EM radiation, IR in the present case) always moves energy from a warmer body to a cooler body (statistically, anyway). If this is the case, you are right. If this is not the case, you continue to suffer from the delusion that incessant repetition will ultimately lead to the acceptance of garbage ideas. Followers of Lyndon LaRouche believe this kind of thing. blackcloak (talk) 09:13, 20 March 2010 (UTC)

Blackloack, no anount of radiation, blackbody or vibrating gaseous molecules can transfer any heat or thermal energy from a first body to a second that has a higher temperature, the heat always goes from the body with the higher temperature to one with a lower temperature, if you don't understand that all the rest of your physics is a waste of time and you would be extremely injury prone in a kitchen.

History is packed with nutty inventors who have claimed this, you will find a good article about the sincere but illinformed people who pushed this idea here [23]. All explanations of the greenhouse effect are fully signed up to this (relatively) new way of challenging the second law of thermodynamics. You guys are a nice bunch of dreamers but your efforts to explain climate variability is quite contrary to any experimental or theoretical physics. You really should look at these matters as a question of thermodynamics. Or perhaps you think thermodynamics doesn't apply in climatology, just like the guys at EAU/CRU think they don't have to justify their statistical conclusions when contribuing to IPCC ARs.

By the way, why do I have to explain the second law of thermodynamics to you, surely I am not the first? --Damorbel (talk) 12:10, 20 March 2010 (UTC)

Try this. It partially explains why cloudy nights are warmer than clear nights.

E = s (Ta⁴ - Tb⁴)

The net heat flow is from warm to cold, but the rate of heat loss is reduced because cold air is a lot warmer than absolute zero. In order for the number of watts returned to the surface to be higher than the number emitted to space, it must be assumed that the atmosphere is IR opaque, that a warm lower layer is radiating toward the Earth, and that a cold upper layer is emitting toward space.

By the way, a blackbody at 15°C emits 390 W/m2. Since 324 is about 83% of 390, it appears that 324 W/m2 is about correct for an atmosphere at 15°C, which then implies that the emission is from the lower 100 meters of the basically opaque atmosphere. Q Science (talk) 14:49, 20 March 2010 (UTC)

So the greenhouse effect may be caused by clouds, not so much by CO2 then? The clear/cloudy night effect indeed arises from the absorption/reflection characteristics of clouds but aren't you are getting into Svensmark cosmic ray territory here, isn't this rather unusual for you?

What do you mean "the number of watts returned"? Watts are joules per second and in your case they are apparently heating a surface that is warmer than the place the Watts are coming from. Real CRU stuff this, if the facts don't fit the theory, change the facts. Do please keep things simple, do produce an explanation without the cool atmosphere making the surface hotter than the atmosphere itself. (Hint, try the effects of gravity and adiabatic heating, or is that not allowed in "climatology"?)--Damorbel (talk) 17:03, 20 March 2010 (UTC)

What on earth does any of this have to do with cosmic rays? Yes, clouds are a part of the greenhouse effect (although they change the earth's albedo as well, so it's a little complicated), so is water vapour, so is methane, so is ozone, so are CFCs. This is explicitly mentioned in the article, and this article in particular doesn't pretend that the greenhouse effect is due to one thing and one thing alone.

I think it's worth considering that even if it is clouds responsible for the greenhouse effect, they are still violating your imaginary second law of thermodynamics. While you acquaint yourself with the actual theory, I suggest you also review the Dunning–Kruger effect to ensure you haven't become a victim of that as well. The suggestion that every physicist in the world has missed the fact that the entire field of climatology violates one of the most fundamental physical laws is ludicrous. StuartH (talk) 20:36, 20 March 2010 (UTC)

Well, actually you are the first one to describe the second law of thermodynamics in such a special way, i.e. applying it to EM radiation moving in a unidirectional way (warm to cool), while refusing to use the concept of a net flow. I notice you chose not to address any of the numbers in the chart. I notice that your link to perpetual motion is indeed curious since your response to my challenge some time back led to the creation of a perpetual motion machine. As for your use of the term "body" I'll initiate another play-dumb game. When you used the term "body" did you mean a large mass (in particular large enough that common ways of measuring temperature can be used)? Do you also apply the term to single atoms/molecules? (Do you see the beginnings of the trap?) And, yes, I fixed your indents, again. blackcloak (talk) 19:50, 20 March 2010 (UTC)

Blackcloak. You say "actually you are the first one to describe the second law of thermodynamics in such a special way" Heat is transferred with radiation from hotter to cooler by the same law, even the GH Effect seems to recognise this. Haven't you just written something rather foolish? --Damorbel (talk) 13:32, 21 March 2010 (UTC)

I guess we have to revert to basics. Do you believe in the concept of negative numbers? Assuming you answer yes, do you believe that if you add a negative number to a positive number that the result of the summation is a number that is less than the positive number? If I get the correct answer the these two questions, I'll know I can move on to a discussion of "net" flow. blackcloak (talk) 04:16, 22 March 2010 (UTC)

There's a good post on that flawed second law of thermodynamics here: [24]. You are arguing using an imaginary law of thermodynamics that physicists do not use. You clearly do not understand the laws of thermodynamics, so it would be a good idea to check that page out. StuartH (talk) 20:01, 20 March 2010 (UTC)

StuartH "What on earth does any of this have to do with cosmic rays?" I suggest you wise up on Svensmark's work. For clouds to form from water vapour cloud condensation nuclei are required, Svensmark's hypothesis is that these arise from cosmic rays [25] thus the presence of clouds (with or without precipitation) is related to the level of cosmic rays passing through the atmosphere. Clouds certainly influence heat transfer in the atmosphere by absorption and and emission but they also reflect radiation which CO2 does not. Reflected radiation, with the reflector configured suitably, can lead to its trapping or exclusion, this is how a vacuum flask works. This trapping effect is one way that "warm cloudy nights" can be explained. Also, by absorbing the Sun's radiation, clouds suppress convection at ground level, transferring it to the cloud top.

StuartH "There's a good post on that flawed second law of thermodynamics here: [26]."The 2nd Law deals only with temperature difference and energy transfer, the energy transfer showing up only as a change in temperature. To quote your link "My boring thermodynamics books and I have long since had a parting of the ways" Where the author goes wrong (as does the greenhouse effect article, see this diagram [27]) is assigning Watts i.e. energy, to a radiation field; how ever many watts are in the radiation field there is no "net" (i.e. heat) energy transfer by the radiation field unless there is also a temperature difference. A red hot mass of iron is generating radiation from every atom but heat is transferred only from high temperature parts to low temperature parts. Now for iron, as a solid, heat is tranferred by vibrations as well as radiation. In a gas heat is trasnsferred by atomic (or molecular) collisions, see kinetic theory as well as radiation for the so called GH gases, there is nothing special about this but it does explain why some gases glow in the infrared when hot and others don't e.g. helium, argon etc. (N.B. these gases do glow when ionised, this does not happen at the Earth's atmospheric temperatures.)--Damorbel (talk) 13:32, 21 March 2010 (UTC)

You're still not conveying a clear understanding of thermodynamics at all. Firstly, Svensmark's speculative hypothesis about the origins of clouds is irrelevant to the question of whether or not clouds violate the second law of thermodynamics. "It's reflection" isn't an answer either, you cannot violate the second law using reflection, and a vacuum flask at no point allows the net flow of heat from cooler to warmer. It inhibits the rate of flow from warm to cool, exactly how the greenhouse effect works.

The diagram doesn't just include the transfer of heat through radiation, it includes all heat flows between the surface and the atmosphere. To demonstrate a violation of the second law, you need to demonstrate where there is a net flow of heat from a cooler body to a warmer body. There are four bodies of interest here -- the sun's surface, the earth's surface, the atmosphere and free space. Every possible combination of these involves a flow of heat from warmer to cooler. It is also assumed in the simplified explanation that the earth's surface is in balance, and so is the atmosphere -- that is, heat in equals heat out and there is no warming over time. Because the greenhouse effect is changing and the planet is warming, this isn't actually true, but it's still a useful explanation. So where is the net flow of heat from cooler to warmer? StuartH (talk) 16:46, 21 March 2010 (UTC)

StuartH "It inhibits the rate of flow from warm to cool, exactly how the greenhouse effect works." Read the Greenhouse effect article carefully, the effect attributed to CO2 is that "it radiates to the surface warming it" look at the diagram [28] and read what it says at http://en.wikipedia.org/wiki/Greenhouse_effect#Basic_mechanism. The basic mechanism is about as clear as mud but it is supposed to be radiation from CO2, H2O etc. that raises the temperature of the surface by 33K above its equilibrium temperature of 255K. "So where is the net flow of heat from cooler to warmer?" Good question, but the surface will only have its temperature raised above the equilibrium by radiation from CO2 if there is a a net inflow of energy and that cannot come from the co\d troposphere for the reasons I gave. --Damorbel (talk) 14:13, 22 March 2010 (UTC)

Yes, that is how greenhouse gases inhibit the flow of heat from the surface to free space -- by absorbing some of the radiation and reradiating it to the surface. If it's clear as mud to you and you have a suggestion to improve it, voice that suggestion by all means, that is what the talk page is supposed to be about after all. If you're unsure how the surface of the earth can heat up, take another look at the graph. The surface gets 168 W/m² from the sun, 324 W/m² from the atmosphere, loses 452 W/m² to the atmosphere, and loses 40 W/m² to empty space. Energy in equals energy out. If you enhance the greenhouse effect, less radiation escapes into free space and more is returned to the surface. The surface will then heat up until radiative balance is restored. The net flow between the surface and the atmosphere remains positive, and at no point violates the second law. The surface is warming because the flow from the sun remains the same while the net flow into the atmosphere goes down. StuartH (talk) 23:39, 22 March 2010 (UTC)

break 1

Doesn't "net flow into the atmosphere goes down" mean that the atmosphere will get cooler? Q Science (talk) 04:44, 23 March 2010 (UTC)

Not if the atmosphere is also radiating less heat out into free space. In fact, the atmosphere warms because the net flow out into free space falls by more than the net flow into the atmosphere from the surface. StuartH (talk) 05:23, 23 March 2010 (UTC)

So, if you increase the number of emitters, then the amount of radiation to space decreases? Also, when the atmosphere's temperature increases, the radiation to space decreases? Q Science (talk) 07:05, 23 March 2010 (UTC)

I'm not quite sure what you mean here... when you say "increase the number of emitters" do you mean increase it from just the surface to the surface + the atmosphere? It's not a case of adding independent emitters. What's happening is that adding greenhouse gases absorbs radiation that would otherwise make it through the atmosphere unimpeded. Some of it gets re-radiated to the surface, some of it gets re-radiated out into space (but less effectively because the atmosphere is cooler than the surface). When you say "when the atmosphere's temperature increases, the radiation to space decreases", I think you're looking at it backwards. The greenhouse effect traps heat and decreases the loss of heat from the atmosphere through radiation. That warms the atmosphere (and surface, indirectly)... so that is the link between falling radiation to space and a heating of the atmosphere. But as the surface and atmosphere warm, they in turn emit more radiation and eventually a warmer equilibrium is reached. I hope some of this is making sense... StuartH (talk) 09:47, 23 March 2010 (UTC)

(outdent) I think we disagree on the following

The greenhouse effect traps heat and decreases the loss of heat from the atmosphere through radiation.

It should say

The greenhouse effect traps heat and decreases the loss of heat from the surface directly to space through radiation.

In fact, the theory specifically says that the radiation from the surface will increase if CO2 is increased, but that a smaller amount will be able to reach space. Q Science (talk) 06:06, 26 March 2010 (UTC)

Ah, good point. I should probably have said "The surface is warming because the flow from the sun remains the same while the total net flow from the surface decreases". On the other hand, only 40 W/m² escapes directly into space, with most of it actually radiated from the atmosphere. The greenhouse effect doesn't just apply to the surface, but to radiation from the lower, warmer atmosphere. So I think both are actually correct -- loss from the atmosphere to space and loss from the surface to space both go down, but I'm not 100% sure of what happens to the net flow from the surface to the atmosphere now. It definitely remains positive, but whether it increases or decreases depends on whether reradiation down to the surface exceeds the absorption of surface radiation that would otherwise make it straight out into space. This is drifting a little from my area of expertise, maybe a real climatologist could clarify. I'm guessing it depends on the absorption spectrum and the current concentration of greenhouse gases. StuartH (talk) 08:30, 26 March 2010 (UTC)

The amount of energy from the Earth to space can not change, it must be equal to the amount received from the Sun. Therefore, it is not possible for the amount released from the surface AND the amount released from the atmosphere to both decrease unless the albedo increases. Since warming causes ice to melt, it is generally thought that the albedo will decrease. Q Science (talk) 15:56, 26 March 2010 (UTC)

You're talking about the equilibrium, I've been talking about the change before equilibrium is reached. Initially, heat loss from the earth goes down, until the earth warms and the heat loss eventually matches the heat gain from the sun. At equilibrium, a stronger greenhouse effect certainly implies a decrease in radiation directly from the surface and a corresponding increase from the atmosphere, but if you take "the amount of energy from the Earth to space cannot change" too far, it would be impossible for the greenhouse effect to warm the earth. The amount of energy radiated out into space can decrease, but that warms the earth until it increases back to the equilibrium position. StuartH (talk) 23:10, 26 March 2010 (UTC)

Don't use the word trap because the idea of releasing the heat is not included. If you insist on using trap then also, for each time trap is used, also use release. Heat moves into the atmosphere during the day and out of the atmosphere during the night. I prefer the words "temporarily retain" to describe the process. An equilibrium point is somewhere between the minimum and maximum points in the diurnal retained heat profile. We use this magic equilibrium point (estimate) for the purpose of computing long term thermal balance numbers. Long term, energy in equals energy out (except for the small amount that might be attributed to global warming, say .05 degrees per year, and a variation well in the noise of temperature estimates in any given year). Short term (hours), the is no equilibrium, and energy in from the Sun does not equal energy out (IR out into space, plus reflected sunlight). blackcloak (talk) 20:15, 26 March 2010 (UTC)

True, I guess some care does need to be taken with the terminology used. "Trap" is a simplification that isn't entirely accurate. StuartH (talk) 23:10, 26 March 2010 (UTC)

outdent and break

Think of a laser pointer. It does not matter what you point it at, the number of photons per second remains the same. When you point it at the Sun, the number of photons is the same as when you point it at a wall. Blackbodies (and greenhouse gases) are the same, they emit a certain amount of energy (as photons) depending on their temperature. It does not matter if nearby objects are hotter or colder, the emitted watts per square meter are the same. This is how a cold atmosphere is able to help heat a warmer body. In the case of the atmosphere, energy from a 270K atmosphere raises the temperature of the Earth by about 33K. Notice, the atmosphere does not heat the surface to 288K, but it adds 33K to the temperature produced by the Sun. Q Science (talk) 16:53, 21 March 2010 (UTC)

I have to disagree. A laser is not a black body, it is monochromatic, it output doesn't conform to a blackbody spectrum. The amplitude of its output (at its characteristic frequency) could be that of any number of blackbody temperatures. But a blackbody emits energy on a vast number of frequencies, to be a true black body the spectrum must be the same as that defined by the Planck formula, the Planck spectrum. Even so the laser will transmit energy to a hot body if the irradiation from the laser has a greater amplitude than the amplitude of the blackbody spectrum at that wavelength (and vice-versa), it is just that the word temperature has lost its meaning.

With the last few words of your entry, you're starting to get closer. EM radiation interacts with individual atoms/molecules, therefore affecting the energy of a picoscopic, local volume. The concept of temperature at such a microscopic level becomes hard to define. I could attempt to provide one, but it would be quite a diversion from the thread of this discussion. It is easier to restrict oneself to a macroscopic definition of temperature, and perhaps further restrict any discussion of temperature change to relatively large changes in a (macroscopic) body's temperature like 0.000001 degrees- i.e. the change in temerature of say a cubic mm of water after absorbing say 10^10 IR photons (guessing on orders of magnitude). blackcloak (talk) 04:33, 22 March 2010 (UTC)

If you consider two adjacent blackbodies (or two blackbodies with their images focussed on each other by a lens) the temperatures are not added, don't you think that would be absurd? They just exchange energy according to the temperature difference, that is how heat works.--84.196.128.194 (talk) 22:09, 21 March 2010 (UTC)

If a laser bothers you, then consider a flash light. (Hot wires are blackbodies.) It really does not matter. The point is that anything that emits photons will do so and it does not matter if the photons are traveling toward a dark or bright object or to a hot or cold object. Q Science (talk) 01:24, 22 March 2010 (UTC)

Q Science, a laser should bother you for the reason I give i.e the spectrum of a laser has nothing to do with blackbody radiation and thus temperature which is at the heart of the GHE hypothesis.

Take your flashlight, let us say the filament is at 2700K, to avoid getting your fingers burnt you focus its image on the Sun at 5780K but don't forget that simultaneously you have also focused the Sun's image on the filament, melting point 3695K, what happens?.--Damorbel (talk) 08:08, 22 March 2010 (UTC)

Because of 1/R², the effective temperature of the sun at the top of the atmosphere is only 120°C (394°K), somewhat less at the surface. So, the filament is much hotter than the Sun. The reason it is dimmer has to do with the total number of photons emitted which is dependent on temperature AND the surface area. However, your focusing argument is good. There are solar furnaces where an array of mirrors focus the Sun to a small spot, reaching temperatures above 3,500°C. These work because IR radiation is additive which, it turns out, is also why cold Greenhouse gases are able to heat the surface. To paraphrase a bit, the equilibrium temperature of an object is based on the sum of the radiation from all available sources. You can prove that this is true by starting a fire with a magnifying glass. Q Science (talk) 17:09, 22 March 2010 (UTC)

"total number of photons emitted which is dependent on temperature" No Q Science, the number of photons is not dependent on the temperature it is the energy of the photons that is dependent on the temperature, see Wien's displacement law, that is why I inserted a lens, the maximum temperature that can be achieved in a focused image of an incandescent source depends only on the source temperature. The number total number of photons coming from a source depends on the number of emitting particles, which may indeed be related to the area. --Damorbel (talk) 21:18, 22 March 2010 (UTC)

This distinction between number an energy of photons is the reason why the climatological energy balance diagrams with Watts per square metre all over the place are really not up to the job of describing the themal behaviour of the planetary atmosphere. For heat transfer it is neccessary to know the energy of the photons because 1W/m^2 may comprise a large number of low energy photons (from a low temperature source) or a fewer number of higher energy photons (from a source with a higher temperature). --Damorbel (talk) 21:18, 22 March 2010 (UTC)

When you increase the temperature of a blackbody, the color changes (Wien's displacement law) and it gets brighter (number of photons increases, see the first image in Blackbody). Q Science (talk) 04:58, 23 March 2010 (UTC)

Photons are emitted by particles, one at a time. The hotter the particles the higher the photon energy, basic quantum theory. The energy of the photons is the product of the characteristic frequency and Planck's constant E=hv.

This description of an oversimplified understanding fails to express the true nature of, ahem, nature. The temperature of a "particle" determines an associated bb curve, the peak of the emission (power vs. wavelength) curve occurring at a wavelength that depends on that temperature. A large portion (depending on where you set thresholds) of the emitted radiation is well above (longer in wavelength) the "peak wavelength" and some is well below the "peak wavelength." Bringing E=hv into the discussion is a red herring since the equation gets at temperature indirectly through energy. This is classic misdirection, one of Damorbel's favorite passtimes. If he wanted to make his point based on physics, he would provide a basic equation that expresses a functional dependence of emitted photon frequency on "particle" (presumably, macroscopic) temperature. And, taking a bit of a stretch here, I'll assert such an equation does not exist. blackcloak (talk) 16:54, 23 March 2010 (UTC)

Blackcloak, I don't think your contribution adds anything to my necessarily simplified explanation of why photon energy plays a vital roll not only in quantum interactions but in heat transfer also. After all, Planck's law of thermal radiation was the first accurate description of what was later described as quantum mechanics.--Damorbel (talk) 19:52, 23 March 2010 (UTC)

What morsel survives contempt when seeming wisdom defiles logic? blackcloak (talk) 07:30, 24 March 2010 (UTC)

I have tried to get the concept of low energy and high energy photons accross. Try looking at it this way, it is exactly the same as with matter; matter contains energy proportional to its temperature, a large amount of matter at a low temperature may very well contain exactly the same energy as a smaller amount at a higher temperature, the important fact being the higher temperature material may burn your fingers whereas the larger, cooler mass won't.--Damorbel (talk) 08:26, 23 March 2010 (UTC)

I think the number of photons is pretty much irrelevant, but the simplified diagram is just representing the heat flux between the surface, sun, atmosphere and free space. In this context it doesn't matter how much energy each photon has -- i.e. what the wavelength of the photons is, it's a straight heat balance diagram. Obviously the diagram isn't going to describe every aspect of the climate completely, but it doesn't attempt to. If you have what you believe to be a better diagram, suggest it for inclusion. StuartH (talk) 05:47, 23 March 2010 (UTC)

"what you believe to be a better diagram" You cannot consider heat flow without accounting for temperature differences (very basic science!) no tempperature difference no - heat flow. The whole concept of the heat flow diagrms showing W/m^2 in the Greehouse effect is mistaken. It may be difficult to accept but when you think about it temperature difference is what drives heat flow, the very idea that heat (that is heat energy) can flow somehow from the colder tropsphere to the warmer surface, causing warming of the surface, is a classic misunderstanding of thermodynamics --Damorbel (talk) 08:26, 23 March 2010 (UTC)

There is no net flow from the cool atmosphere to the warm surface. You have the numbers from the graph, and it would be trivial to demonstrate a violation of the second law if it were there. If you have no further interest in improving the article or understanding the basic physics, I have no further interest in continuing this discussion. I can only suggest that you consider how unlikely it is that the entire field of climatology violates one of the most fundamental physical laws, while every physicist in the world allows them to do so. If it's between you being wrong and every physicist and climatologist in the world being wrong... maybe it's you. StuartH (talk) 09:24, 23 March 2010 (UTC)

No one is saying what you're attributing to others. Here is what they are saying, using your words and terms: ..heat can flow from a cooler body to a warmer body, causing the warmer body to cool more slowly than it would were it not for the presence of the cooler body. I know that may sound unnecessarily complicated to you, but that fairly describes the complexity required to explain nature. blackcloak (talk) 01:23, 24 March 2010 (UTC)

Blackcloak "..heat can flow from a cooler body to a warmer body, causing the warmer body to cool more slowly" this not what the GHE claims, what you describe here is conduction of heat which is a diffusion process governed by the heat equation. Your remark "to cool more slowly" indicates your line of thinking since the diffusion equation governs changes of heat distribution with time. I recommend the heat conduction article since it emphasises the distinction between heat conduction, convection and radiation.--Damorbel (talk) 09:11, 24 March 2010 (UTC)

No. I was using your words and terms to describe the effect of net energy flow via em radiation, the very case (I thought) you (thought you) were describing. blackcloak (talk) 18:51, 24 March 2010 (UTC)

"There is no net flow from the cool atmosphere to the warm surface." I agree. But the GHE article maintains that the surface is heated 33K above the equilibrium temperature by radiation from GH gases, how does this happen? --Damorbel (talk) 09:34, 23 March 2010 (UTC)

The article does a reasonable job of explaining this. Without a greenhouse effect, the earth would equilibrate at a lower temperature because it can radiate the sun's 235 W/m² directly into space. With a greenhouse effect, equilibrium is reached at a higher temperature because much of the heat radiated from the surface stays in the atmosphere/surface system. It warms up until emitted radiation rises enough to compensate. StuartH (talk) 10:21, 23 March 2010 (UTC)

StuartH "The article does a reasonable job of explaining this". Since the effect of carbon dioxide is said to be that the surface is warmed by radiation from CO2 in the troposphere, it is very difficult to ignore the fact that the surface of the Earth is always warmer than the troposphere above, thus the explanation ignores the basic facts of heat transfer, I fail completely to see how this does "a reasonable job."--Damorbel (talk) 19:52, 23 March 2010 (UTC)

It is fundamental for thermal equilibrium that the planet radiate away all 235 W/m² that it has absorbed. Because of the greenhouse effect, the only way the top of the atmosphere can radiate this much is if, beneath it, there is an even higher temperature providing enough net inflow into the bottom of the atmosphere that the atmosphere can radiate a lot of that back down again and still have enough heat left to put 235 W/m² back out upwards into space. When a person sleeps under a blanket, the blanket is colder than their body, but still keeps them warmer than if it wasn't there. The difference then is that the unchangeable fact is that the person's body will have to lose, I dunno, 300 W all night and no one cares what escapes the blanket, so the equilibrium is caused by a different thing, but still it's warmer under the blanket. Wouldn't a better place for these questions be Wikipedia:Reference desk, as they must be helping people understand the physics, but they are not helping to improve this article per WP:TPG. --Nigelj (talk) 10:35, 23 March 2010 (UTC)

Nigelj, are you seriously comparing the Earth's atmosphere to a blanket?. One tends to think you are joking, funny for today. Wikipedia suffers quite a lot from such contributions, they waste space and are only sometimes funny. There is nothing in the GHE article to suggest a blanket. --Damorbel (talk) 15:25, 23 March 2010 (UTC)

I think you need to have a look at WP:TPG and decide in which way you would like to help improve this article, then make your suggestions here if you have any. Then have a look at WP:NPA and bear in mind that this article and this talk page are under article probation. All of this is explained at the top of this page. --Nigelj (talk) 16:12, 23 March 2010 (UTC)

I suggest that you should first explain the blanket idea here if it is to be included in the article. I would very much like to have a clear idea what particular charateristics of a blanket are to be considered relevant to an atmosphere? Also, are there any limitations in the analogy? That is to say are some features of a blanket to be excluded from the atmosphere as a blanket model? --Damorbel (talk) 16:29, 23 March 2010 (UTC)

My answer to your question above was given in the spirit of Wikipedia:Reference desk, but any further such questions should, as I said, be directed there. Well-sourced suggestions to improve this article are, of course, welcome here. Thank you for your interest. --Nigelj (talk) 16:49, 23 March 2010 (UTC)

Nigelj, I think I understand from this that you consider explanations involving the atmosphere behaving like a blanket are not appropriate in an article about the Greenhouse effect.--Damorbel (talk) 19:52, 23 March 2010 (UTC)

It is time to close this. Wikipedia is not a general forum for discussion (even about the topic of the article). Damorbel if you have griefs about the greenhouse effect and the laws of thermodynamics then you can take it to the Wikipedia:Reference desk. So far you have only been a time-sink. I'm sorry to have to inform you, that your interpretation is wrong - and we are not here to correct you. --Kim D. Petersen (talk) 20:31, 23 March 2010 (UTC)

I'm starting to agree. I made a good faith attempt to correct a clear misunderstanding of another contributor while maintaining a sliver of hope that the discussion could improve the article. Explanations for Damorbel's misunderstanding have been presented by more knowledgeable people, and Damorbel either willingly ignores those explanations or lacks the capacity to understand them. I have no further interest in contributing to this discussion without the possibility of improving the article. StuartH (talk) 21:23, 23 March 2010 (UTC)

Ah! KimDabelsteinPetersen, "I'm sorry to have to inform you, that your interpretation is wrong - and we are not here to correct you." So kind, your clear explanation of the physics and a firm decision!--Damorbel (talk) 21:51, 23 March 2010 (UTC)

This matter has been explained to you, again and again, over years, at all levels between expert and kindergarten. Either you are incapable of getting it, or you are a troll. Please stop wasting our time. Thanks. --Stephan Schulz (talk) 07:59, 24 March 2010 (UTC)

Stephan, you write 'This matter has been explained to you, again and again'. I understand from this you are citing the arguments of others, not your own. This suggests you are unable to make the case yourself for CO2 warming the surface by as described in the GHE article. Now the article claims that CO2 (and other GHGs) in the atmosphere are transfering heat to the surface by radiation and warming said surface by 33C above its equlibrium temperature; this is also the position of the IPCC. The argument is deeply flawed in that atmospheric CO2 is always colder than the surface; what actually happens is the heat flows from the surface towards the GHGs, i.e. the direct opposite of the claim. The relevant science of heat transfer is called (thermodynamics) has been established for many years. One of its most tested laws is the 2nd law which says it is impossible for heat to flow from a cold body to a hotter one, it always flows in the other direction, warming the colder, never the hotter; as happens in common experience.

Now it may well be that you are able to make the case for surface warming by tropospheric gases, personally I cannot wait to read it because, should it be a good one, the world of physics would have to be rebuilt from its very foundations--Damorbel (talk) 19:07, 24 March 2010 (UTC)

Apparently your memory is failing. I explained this stuff to you ages ago, for about an eternity. Unfortunately, you have learned nothing from it. George Santayana had something appropriate to say about this... --Stephan Schulz (talk) 22:16, 25 March 2010 (UTC)

OK, skip the reference desk. Write direct to the IPCC, tell them they got it wrong, then come back here with the new reference when they publish their correction based on your research. Until then there's nothing we can do for you here. --Nigelj (talk) 20:51, 24 March 2010 (UTC)

Nigelj, "Write direct to the IPCC, tell them they got it wrong". Poor IPCC! Yet again? What with Pachauri's melting glaciers and Mann's straight hockey stick, surely there is enough to ensure its oblivion.--Damorbel (talk) 22:07, 25 March 2010 (UTC)

If you actually read 2nd lawyou'd know that it is not impossible for heat to move from a cooler particle to a warmer particle. Experiments have confirmed that this can occur. You'd also know that the law is intended to apply only to macroscopic systems. An emitting molecule and an absorbing molecule do not constitute a macroscopic system. And, you might even note that radiative heat transfer is not even discussed. In fairness to us, at the very least, your arguments should not be contradicted by your own sources. blackcloak (talk) 02:12, 25 March 2010 (UTC)

Blackcloak, "Experiments have confirmed..." I think this statement deserves at least two links, and not to a refrigerator... please!--Damorbel (talk) 21:52, 25 March 2010 (UTC)

I respectfully decline your request for what should be obvious reasons. blackcloak (talk) 07:20, 2 April 2010 (UTC)

Rule 5, to the fifth power, five times every five days for five years. Short Brigade Harvester Boris (talk) 01:32, 27 March 2010 (UTC)

Proof?

There is disputed proof on the Greenhouse effect existing. Carbon is a natural element of planetary life, on top of that the Greenhouse effect has shown significant water level rise before the 20th ce. I have two maps of India, one map is 600 years old. The shoreline in the old map shows that most of the google earth villages and cities around the shoreline right now was underwater. I also study geology so I was able to simulate a map of the ice age where most of the continent, through drift analysis, was underwater 80,000 years ago. The continent of India looked much like a sharp narrow tooth. So to say water is receding or climbing due to climate change is a lie. It can recede and it can expand because of a minute geological shift, or when plates move quickly over a given time by planetary impact (this happens when most life is extinct). When the earth turns everything moves quickly. The state of life is then returned to savagery which later through time does chain reactions of the environment occur. The water or enormous current then decides which land sinks and which doesnt. Eg sea level rise. The melting of the iceage's glaciers was proof of this fundamental law of sea levels rising and still is occuring today through natural process. The lowering of sea levels can be because of geogical shifts and occurs naturally in low level seas or old ocean areas. The idea about marketing is interesting. It holds fundamental laws to some shoreline areas to be true, albeit the facts are not verifiable. Eg over time Mars will die like any planet, its carbonated gas will be on the planet's surface like the dead life of organisms is in the oil of our planet. It will collect over a large period of time. --64.9.241.30 (talk) 00:45, 30 March 2010 (UTC)

...and your suggestion for improving this article is...?--CurtisSwain (talk) 11:53, 2 April 2010 (UTC)

Proposed rewrite of The distinction between the greenhouse effect and real greenhouses

This section is kind of rambling and redundant. I propose parring it down to

While there are some similarities between the atmospheric "greenhouse effect" and the heating mechanism of the structure from which the name is derived there are important distinctions as well. A greenhouse heats its enclosed space primarily by the prevention of convection cooling. Because a greenhouse is transparent to sunlight, solar energy passes through the enclosure unimpeded and warms the ground inside. The ground in turn warms the enclosed air which continues to heat because unlike the warm air near the surface outside, the trapped air is prevented from rising and pulling in cooler air behind it.

The climatic greenhouse effect is similar in that, like the greenhouse, our atmosphere passes sunlight nearly unimpeded. Both also limit the rate of thermal energy flowing out of the system. The heat trapping mechanisms, however, are very different. The atmosphere, which like a glass enclosure, is transparent to sunlight but it is not transparent to the energy being radiated back up from the earth's surface. Some of this radiant energy is reabsorbed by greenhouse gases and is prevented from escaping into space. This reabsorbed energy keeps the planet warmer, much the way a blanket warms us by preventing our body heat from escaping.

This is a layperson's explanation of the essential difference. I may have boiled it down to much. Comments?JPatterson (talk) 22:40, 3 February 2010 (UTC)

For a greenhouse to be warm, it have to prevent *all* means of heat transmission. That includes convection, conduction *and* radiation. If any of them is not prevented at all, the greenhouse will cool down to the environment temperature. —Preceding unsigned comment added by 213.216.225.18 (talk) 18:38, 6 April 2010 (UTC)

Major rework

Prompted somewhat by the above, I've done a major re-work of several sections of the article which are now (I contend) more accurate as well as shorter, at least in some cases William M. Connolley (talk) 21:45, 4 February 2010 (UTC)

Looks good, other than the link to perhaps the worst definition of sensible heat I have ever laid eyes on :>). Thanks for the effort. Sorry mine fell short.JPatterson (talk) 21:51, 4 February 2010 (UTC)

You're right. I didn't get past the first sentence without going "argh" William M. Connolley (talk) 22:34, 4 February 2010 (UTC)

...so I fixed it William M. Connolley (talk) 23:50, 4 February 2010 (UTC)

Is this correct?"

"In the case of the greenhouse effect the rate of radiation from the Earth to space is limited by the greenhouse". The implication here seems to be that eventually all E->S radiation escapes but that it just takes longer than would be the case sans GHG. I.e. from the ideal model:

The infrared flux density out of the top of the atmosphere:

$F\uparrow =\epsilon \sigma T_{a}^{4}+(1-\epsilon )\sigma T_{s}^{4}$

$F\uparrow$ has units $Wm^{-2}$ so I assume $\sigma T_{s}^{4}$ is the "radiation from earth to space" above. Seems to me the only way $F\uparrow =\sigma T_{s}^{4}$ is if $\epsilon =0$

Is it the rate that is limited or the magnitude? JPatterson (talk) 00:53, 6 February 2010 (UTC)

I have a fun suggestion for you. I'll hold off answering for a while. Get a few of the oh-so-knowledgeable sceptics (you know, the ones so expert on climate science) to try their hand at answering William M. Connolley (talk) 08:35, 6 February 2010 (UTC)

"the ones so expert on climate science". WMC it's much more of a physics question, doncha think? --Damorbel (talk) 11:20, 6 February 2010 (UTC)

No hints I'm afraid. Please put your answer up William M. Connolley (talk) 13:26, 6 February 2010 (UTC)

I noodled through it on my commute home last night. If the outbound radiation suddenly dropped to zero the temperature would not drop instantly but rather decay in some sort of exponential fashion. So there is a time constant involved and it is in fact the rate of energy loss that is being decreased by the GE. I now imagine the atmosphere is rather like a large water tank, with the outbound radiative energy represented by water filling the tank at the top, and the space-bound energy represented by a hole in the bottom. The GHGs make the hole smaller which increases the time the tank would take to empty if the valve were shut off at the top.

Still you've introduced time (rate) into the picture while all of the diagrams show static processes. It would make the article more accessible I think if we could illustrate this time flow of energy somehow.

JPatterson (talk) 17:51, 6 February 2010 (UTC)

It appears that you have assumed that the only way that heat gets into the atmosphere is via radiation. However, convection is also important. As a result, in a cloud free sky, greenhouse gases will always emit more heat than they absorb. Also, when water vapor condenses to form clouds, some of that energy is released to space, increasing the outgoing radiation beyond the equation you presented above. In addition, the clouds themselves emit as blackbodies, adding yet another term to the equation. If the amount of heat from convection and condensation is greater than the amount released by clouds, then the greenhouse gases will still release more heat than they absorb. In that case, adding more greenhouse gases should increase the size of "the hole" by allowing the atmosphere to release energy faster. (At least, that is my understanding.) Q Science (talk) 09:45, 8 February 2010 (UTC)

Q science you make some very weird statements "greenhouse gases will always emit more heat than they absorb" and "when water vapor condenses to form clouds, some of that energy is released to space" etc. etc. Frankly I cannot see how this sort of stuff is going to improve the article. --Damorbel (talk) 10:38, 8 February 2010 (UTC)

Let's assume that greenhouse gases absorb 80 W/m2 via IR radiation. Let's also assume that the atmosphere absorbs 20 W/m2 via conduction/convection (called sensible heat). In this case, the atmosphere now contains an increase of 100 W/m2 of heat. Since the temperature of the atmosphere does not change (in this scenario), the greenhouse gases must release 100 W/m2, 20 W/m2 more than what they absorbed via the same mechanism. Q Science (talk) 19:14, 9 February 2010 (UTC)

I wasn't assuming anything, just trying to get straight in my own mind whether of not GHGs reduce the rate of radiative energy flowing into space (as the article states) or its magnitude. Nor DB, was I proposing my tank analogy be placed in the article. Although I think it has some merit in helping to visualize the effect of GHG on thermal equilibrium (e.g. as the water level rises, pressure at the bottom increases, increasing the amount of outbound flow. When the outbound flow = the inbound flow, the water level (representing temperature) stabilizes. If the hole is made smaller, a new equilibrium is reached at a higher level), but I doubt one could find an RS that backs this up. JPatterson (talk) 14:21, 8 February 2010 (UTC)

Since WMC did not respond to my challenge some time back, I won't respond to his. I do know the answer (after suitably cleaning up the poorly formed question). Those who have read my comments, primarily at the Greenhouse Gas discussion page, and understood what they read, should have no difficulty answering the above question. Here are three observations/guesses about responses. 1) Damorbel won't respond because he knows from experience that he'll get it mostly wrong. 2) WMC will get it mostly right, but his response will be so terse that it will not satisfy the discriminating reader. I think he does this because he likes to leave himself plenty of wiggle room. 3) JP's model doesn't work, in one key respect, in the limit, so he's so lost he may not even believe the correct answer. blackcloak (talk) 07:16, 2 March 2010 (UTC)

Not keen

On [29]. Calling outer space a thermal reservoir isn't right William M. Connolley (talk) 16:48, 14 April 2010 (UTC)

Good point, I've rephrased it slightly. The caption is getting a bit long anyway... StuartH (talk) 06:20, 15 April 2010 (UTC)

Your edit amounts to a reversion, my new version correcting earlier problems. One is the improper use of the word between. I think we should wait for an explanation of what the problem is, not just where it is. blackcloak —Preceding unsigned comment added by 67.87.73.86 (talk) 06:36, 15 April 2010 (UTC)

Feel free to consider it a reversion. If you have a problem with the word between, I'm not seeing it, but I'm happy to adjust it further. But I agree that "reservoir" is incorrect. Space does not satisfy any definition of "reservoir" that I'm aware of. It's not "storing" the energy, by radiating it out into free space, free space is acting as a sink. StuartH (talk) 06:58, 15 April 2010 (UTC)

Reservoirs both receive and release energy/matter. We know 3 degree outer space is the source of long wavelength radio waves, and so is also a source, technically. But more to the point, the structural changes in the sentence led to greater clarity by alerting the reader to the general class of the bodies before identifying them individually. In principle, this should lead to more rapid understanding. As for the word between, that only applies to two "agents." We say "between the two of us we did ..." We say "among the three of us, we concluded ..." etc. This is basic English, as taught to those of my generation (and older). Now you may think this is a minor point, and for most people you would be correct. Just bear in mind that there will be those who pick up on this error immediately and think poorly of the writer. Will continue to sign off as blackcloak even though SineBot is going to have a conniption. blackcloak

Even if it both receives and releases energy, I don't think the storage implied by "reservoir" is a good fit. Either way, we don't need to call it anything, and the caption works fine just presenting the three "sources/sinks/reservoirs" without giving them a collective name. And "those who pick up on this error immediately and think poorly of the writer" will be conveying a lack of understanding of the language. From Merriam Webster: "There is a persistent but unfounded notion that between can be used only of two items and that among must be used for more than two", "it is especially appropriate to denote a one-to-one relationship, regardless of the number of items", and "Among is more appropriate where the emphasis is on distribution rather than individual relationships". "Between" is a better fit here given the individual relationships illustrated in the figure. StuartH (talk) 08:14, 15 April 2010 (UTC)

Interesting response. Actually the idea of storage is exactly what is needed. Remember, energy is conserved. When it is moved from one place to another, it is removed from storage in one place, and it is stored in a new place. As for the comment about "between" vs. "among," my comment still stands because the distinction is one that is commonly made (as you confirm), the reader (me, for example), isn't likely to go (I haven't) to a dictionary to decide the issue. It's too ingrained. You may feel that your reader doesn't understand appropriate use of the language, but, perhaps, a writer should be thinking just as much about what his reader might think about the writer. And I have a second observation on this issue. Just trying to understand the distinction being made in the quoted dictionary entry takes a little time. The way I read it, "among" is the more appropriate use, according to the quoted definition, because there are no one-to-one relationships; a reduction in transfer rates from a to b is exactly matched by an increase to c. Or, more or less equivalently, you can not talk about transfer rates from a to b without talking about (or at least implicity acknowledging) transfer rates from c to a. It would be like saying, in a conversation among three individuals, at a point when person a is talking to person b, that c does not overhear a, and that c does not integrate an understanding of what was said by a to b in c's later contributions to the conversation. blackcloak

Actually the idea of storage is exactly what is needed except that space can not store energy. True, space is both a source and a sink, but energy radiated from the Earth will not return. Note that reservoirs get hotter (or undergo some other change) when they store heat. However, because space does not have a temperature, adding more heat to it can not raise its temperature, and, therefore, it can not be a reservoir. Q Science (talk) 07:27, 17 April 2010 (UTC)

I can see that you have little if any formal training in (college level or above)physics. Radiation from all directions of space does indeed reach the surface of the Earth. Indeed, space does have a "temperature;" it's about three degrees Kelvin. An obvious source of radiation reaching Earth after leaving Earth (or the Sun, for that matter) is the moon. Certainly power from sources not originating from the Sun are miniscule compared to the Sun, but they are not zero. Note that the volume of space affected by radiation emitted from the Earth is really huge, so any temperature rise due to that radiation will be immeasurably small. Besides, absorption must occur before there would be a temperature rise. The portion of radiation passing through a volume won't add to the (matter based) thermal energy component of total energy in the volume, but it is a second component of the total energy in the volume. In all cases, energy must be conserved. Your limited understanding of the underlying science led you to a conclusion that is inherently incompatible with conservation of energy. blackcloak (talk) 08:56, 17 April 2010 (UTC)

That radiation is coming from the edge of the universe which had a temperature of many thousands of degrees kelvin. It only appears to be cold because of the red shift. And besides, radiation is not temperature. The space around our galaxy is not creating the 2.5K microwave background because that space has no temperature (which is not the same as having a temperature of zero). The radiation from the earth may return in 30 billion years (round trip to the edge of the universe), but will never be returned by being reemitted by some local reservoir. (Yes, I know about the moon, but that is a rock and not "space".) Q Science (talk) 21:22, 17 April 2010 (UTC)

You're not communicating clearly enough. If you're objecting to something I wrote, then state where I made an error in your estimation. The key idea is conservation of energy (mentioned twice). The most challenging thing I wrote to you involved this principle, and you totally ignored it. I'm not used to this tangential form of "communicating." Let me just say that energy entering a reservoir does not remember where it came from and will not (necessarily) return to its source at some later time. blackcloak (talk) 08:25, 18 April 2010 (UTC)

Without matter, there is no temperature. Since there is no matter (substance) to space, it has no temperature. Therefore, it can not store and return heat. Therefore, space can not be a reservoir. My objection is to your use of the word "reservoir". Think of light (another form of electromagnetic radiation). Is space a "light" reservoir? What would a "light" reservoir look like? How would it store "light"? How would it emit the stored "light"? Q Science (talk) 19:01, 18 April 2010 (UTC)

On temperature and "no matter," see outer space. Note caption's gray section includes everything outside Earth's atmosphere, which of course presents plenty of opportunites for absorption, eventually. blackcloak (talk) 07:18, 27 April 2010 (UTC)

Comments like that really don't help your cause. Incident radiation to Earth from space is negligible; Fourier was wrong. So talking of outer space as a reservoir is confusing langauge William M. Connolley (talk) 19:52, 17 April 2010 (UTC)

I work from the assumption that everything I do here (content-wise) is a lost cause. I think there's a song about people who see the (in this case, local) world from that perspective. From someone who has spent a few hours around a car's engine, I suggest you google the term "vacuum reservoir." "Confusing language" is always going to be in the eye of the beholder. blackcloak (talk) 08:25, 18 April 2010 (UTC)

There wasn't really anything wrong with the caption to begin with, and your edit added a whole range of issues. It made it needlessly long, applied grammatical rules that don't exist, and introduced a misleading and incorrect term "reservoir". There's no need to take it personally and question the training of other contributors. From someone who does have formal training in "college level or above" physics, that remark was unwarranted. The source of energy in the figure is the sun, and "thermal reservoir" is a bad analogy given its heat comes from nuclear fusion, not stored thermal energy. CMB is not only a ridiculously negligible source, it's also a poor example of a "thermal reservoir" given its origins shortly after the Big Bang as the universe eventually became largely transparent. Thermal radiation from the earth is unlikely to be absorbed within the Hubble volume (yes, the moon will absorb a tiny, tiny proportion of that, but it will end up radiating almost all of it out into deep space anyway) given the transparency of the universe, making "thermal reservoir" a bad analogy again. Collectively designating the sun and the rest of the universe to be a "thermal reservoir" is just a bad fit. The heat in and heat out has little to do with each other, and certainly nothing to do with storing heat energy. StuartH (talk) 00:39, 18 April 2010 (UTC)

So why do you think I would bother to change the caption if (I thought) there is nothing wrong with it? Do you believe I'm actually trying to make things worse than they already are? If you see it as a bad analogy, fine. Offer a better analogy or term. That would be the positve way to approach this; you chose another approach. I'm not married to "thermal reservoir" as stated elsewhere. The purpose for introducing the term was to help direct the reader to the gray, blue and brown sections of the diagram and introduce the idea that, from a high level perspective, the simplified model of the system has three major components, namely one above the atmosphere, the atmosphere and the "surface" of the Earth. The rates shown represent long term energy transfer rates among the three major components of the system. Regarding your assertion of a grammatical error, I don't see it and do not believe there is one. Are we talking about a UK/US English difference? As for your last sentence, it's more proper to say energy in and energy out. Other than that I can not figure out what the point of the sentence is. I think of heat energy as absorbed (by matter, kinetic) energy which contributes to temperature rise. I think of energy content (in a volume) as kinetic energy plus radiation energy plus the "inherent" energy equivalent of (including excited energy state) matter (it is somewhat more complicated than this, but for present purposes, I can live with this simplified view). blackcloak (talk) 08:25, 18 April 2010 (UTC)

Okay, you're not married to "thermal reservoir", no-one else is supporting it, so we can consider that issue closed. Can we assume the assumption of good faith here? Of course I don't believe you're changing the caption to deliberately "make things worse". But the edit introduced problems that weren't there originally, and your belief that there was something wrong to begin with isn't shared by others. I don't think we need an analogy or a collective name for the "components" of the system, but William's inclusion of the terms "source" and "sink" might help clarify things, and has the added bonus of not being inaccurate and misleading. I think there is probably room for slight expansion of the article itself, and perhaps part of your edit could end up there, but I also don't think a figure caption is the right place for excessive detail. And to clarify my point about grammar, I don't think your edit was ungrammatical, but it attempted to correct a grammatical error which didn't exist (the "can't use between for more than two" non-rule). StuartH (talk) 12:12, 18 April 2010 (UTC)

Since you're responding to the issues much better than the others, I'll direct my comments to you. I expect to make several separated replies addressing various points. On reflection, it does not look like "thermal reservoir" is close enough to the truth to pass muster with those who have responded, and in minor ways they're correct. The word "thermal" (even though "thermal energy" is implied) is just too close the idea of a temperature (change) component. Let me then suggest "energy reservoir" as a more appropriate term. The three elements of the diagram are the Earth and its surface, with the surface being the energetically important part, the Earth's atmosphere, and everything else, referred to as "outer space." In WMC's recent wording change, the outer space part is divided into two parts: the Sun and the rest of outer space. Just as the Sun serves as an insignificant sink, the rest of outer space serves as an insignificant source. Nonetheless, energy must be balanced, so the "rest of outer space" (or "outer space" in the earlier version) must sink just as much as the Earth/atmosphere combination sources (first order approximation), and in turn the Earth/atmosphere must sink just as much as the Sun sources the Earth/atmosphere. Conservation of energy requires this. It doesn't matter if the mechanisms by which "the rest of outer space" accepts/retains the supplied energy are left undefined (and yes, I do regard the source of (okay, most of) QS's comments as one large bucket of red herrings) since the entire volume within which the energy is "contained" is included within the definition of the space. blackcloak (talk) 07:55, 19 April 2010 (UTC)

Now to respond to a second point. While WMC's recent change to the caption is something of an improvement, the second sentence has a serious problem, and it's one that I would have expected you to find if you are really reading things as carefully as you would like us to assume you are. (Go ahead and get your dander up if you have to.) It says "The ability of the atmosphere to capture and recycle energy emitted by the Earth surface is the defining characteristic of the greenhouse effect." As my various comments on conservation of energy have carefully explained, the energy in/out relationship holds for both the surface and the atmosphere (long term average, first order approx, etc.). The present version does not recognize the surface for what it is, rather it treats the two in markedly different ways. The sentence should read "The ability of the atmosphere and the surface to exchange continuously a portion of their retained thermal energy is a defining characteristic of the greenhouse effect." Now I have little doubt that you'll find something to complain about in this wording, but any fixes should not alter significantly the general idea. blackcloak (talk) 07:58, 20 April 2010 (UTC)

Responding now to a third point, the diagram is an island unto itself. Essentially it is a self-contained body of information. None of the numerical details contained within the diagram are discussed in the article. There are no references in the article's text to the diagram. Further the size is too small to read most of the text in the diagram. Why is it there? Or if you prefer, why is it seemingly part of the introduction? Perhaps it should be part of its own section (title, "Energy pathways of the Greenhouse effect"?), with the explanatory information provided by the section's text. Or perhaps it should be removed entirely. Or as another option, replaced with a simpler version- one containing no numbers, but with arrow widths proportional to energy flow rates. Personally I think it is a useful diagram and should be included because it offers a visual way to illustrate the general features, with a little detail, of the greenhouse effect. If an expanded version were to be used, the disproportionate size of an expanded caption would appear less obvious, but a new section would provide a place for an expanded description. Since WMC, QS and you have all mentioned similiar changes/additions, perhaps we can come to some consensus as to direction. blackcloak (talk) 17:48, 20 April 2010 (UTC)

Sorry for not having responded sooner, I've been rather busy in the last few days. If I find the time, I'll address your first two points, but I can tell you now that I agree with your point about the diagram being somewhat of an island and I guess it was what I was getting at when I said the caption was getting too long and that much of the explanation is better off in the body. I'm of the general belief that a figure should be as self-explanatory as possible (I think the current figure satisfies this) and that captions should be as limited as possible. In terms of the figure, if it's important enough to go in the article, it's important enough to address the context in the article itself rather than the caption. Moving in that direction would improve the article. StuartH (talk) 04:21, 22 April 2010 (UTC)

As my final entry on subjects raised in your comments, I want to concentrate on your assertion that my "belief that there was something wrong to begin with isn't shared by others." Of course "others" don't see something wrong, because, had they, improvements would have been introduced long ago. When you use this kind of logic to squash another's attempts to highlight areas of deficiency, you make one or more assumptions. First, you may be assuming that those examining the material with an eye towards improving it have sufficient skill and initiative to identify and correct problems. Second, you may be assuming that enough time has passed that all reasonable improvements have been made, and, accordingly, the threshold for considering changes must of necessity be set higher than it might otherwise be set. Third, you may be assuming editors read (after having read and re-read the material umpteen times) are going to see, miraculously, some problem they have completely missed in the past. Fourth, you may be assuming that those who have valuable insight into improving the quality of these articles are going to bother to make their observations known when the atmosphere for introducing changes is so toxic. Most people just don't enjoy banging their head against the wall, even when they're right. It's easier to just give up, recognizing that the net effect of free-for-all editing is reversion to the mean, and by that I don't mean POV, I mean the quality of the product. blackcloak (talk) 04:29, 23 April 2010 (UTC)

Quick clarification here... my justification for saying that no-one shares your belief that there was something wrong to begin with isn't that no-one noticed anything before, it's that having presented your argument, no-one agrees with it. Your grammatical argument is demonstrably wrong, and the original caption was a reasonable simplification. The article itself is a better place for more detail. Edits are supposed to be about building a consensus, something you do not have. StuartH (talk) 08:38, 23 April 2010 (UTC)

I have no difficulty understanding why "no-one agrees with it." For me, this is not unfamiliar territory. My direct comments should be sufficient to provide the basis of my reasoning and understanding. You keep harping on my "grammatical argument." I refuted your assertion using the definition you supplied. What more can I do? Besides, it's not a grammatical problem, it's one of semantics. Kinda low on the totem pole, don't you think? I urge you to be more careful in your use of the English language. Imprecise language is the bane of an encyclopedia (no, I don't have a reference). As for the original caption, it would have been a reasonable simplification had the diagram itself been a lot simpler. And I do agree, the detail belongs in the article itself. Of course, then, there would be space for more detail than I provided in my expanded caption. I can think of more than a few things I left out of the expanded caption that could now be put in. As for your point about consensus, my view is that improvements don't get made, in this environment, after starting an orderly discussion of a new issue on this page. Rather, changes (whether or not they're improvements might be debatable) are made in reaction to an impulse function applied directly to (a particular part of) the article. That forces the issue. We're in the middle of that process. blackcloak (talk) 05:54, 24 April 2010 (UTC)

blackcloak here. Having logon/pw problems that probably will mean a change in my id. Very disturbing how little fault tolerance is built into this system. Anyway, I'm not married to the use of the words "thermal reservoir." I considered "thermal sources/sinks" but rejected it as overly complex for the context. "thermal reservoir" is not that bad, in my opinion. "outer space" has lots of 3 degree Kelvin volume (finite temperature and finite density, mostly a sink) and occasional high temperature hot spots (stars, sources). Certainly isn't homogeneous, but like more common thermal reservoirs, energy moves in and out of it. Of course, you haven't explained why you think the term isn't right. I might be barking up the wrong tree. blackcloak

On reflection, I think the original is simpler and better. We can't explain the full thing in a caption; so I've reverted it. BC's original edit said it fixed various problems but I don't know what this probs are William M. Connolley (talk) 08:47, 15 April 2010 (UTC)

I'm neither surprised by this action, nor by the failure to understand the problems, of course. I tried, breaking my personal rule about not editing articles. blackcloak

Well, please try (succinctly) to explain the problems with the existing version. Better still, explain the *first* problem only William M. Connolley (talk) 19:52, 17 April 2010 (UTC)

I'll not respond directly to this request, as I've tried this approach in the past and it just makes for more work, and it won't change the outcome. I will try another approach. My version of the caption is designed to assist the reader in understanding the diagram by answering the following questions in what I consider the proper order. 1) What does the reader need to know (not explained in the diagram itself) about the diagram (including visual clues) and the material covered in order to understand the general nature of what is being represented? (e.g. my training tells me incident radiation from the Sun is 1400 watts per meter squared- my caption provides a clue, the original does not) 2) To avoid a time consuming process of carefully analyzing the numbers in the diagram, what helpful assistance can be given to the reader where there are constraints, and implications associated with those constraints, built into the numbers contained within the diagram? 3) As an introductory illustration in an article, what can be said, in very general terms, that will help the reader focus on the key elements of the diagram. 4) What relationships not explained in the diagram are key to helping the reader understand something about important elements of the article? 5) Can some conclusory statement be made that ties the diagram's content to the subject of the article. blackcloak (talk) 08:25, 18 April 2010 (UTC)

A better approach would be to create an article specifically to discuss that image. It is an important image, both because of what it represents and because of its place in the IPCC documents. Unfortunately, such an article would not be allowed under the current rules because 1) it would be based primarily on primary sources and would 2) contain a significant amount of OR. For instance, in the original paper, it is very clear that some of the numbers are measured, some are based on proxies, some are based on theory, and the sensible heat value is simply what was needed to make the rest of the number balance. It is also clear that there is significant uncertainty about the amount of solar energy absorbed by the atmosphere and at what altitude it is absorbed. Q Science (talk) 19:15, 18 April 2010 (UTC)

Sounds like a plausible idea. I wouldn't worry about the rules too much, no-one cares that much except for controversial articles. Just look at, say, picking a totally random example, septic tank - loads of stuff, hardly any refs. No-one minds William M. Connolley (talk) 20:30, 18 April 2010 (UTC)