Talk:Greenhouse effect

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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

greenhouse effect

you should add more detail about what it is and a more recent news on the greenhouse effect — Preceding unsigned comment added by 67.83.135.189 (talk • contribs • WHOIS)

I have been searching to find more references for this article. I found many sites which were based on this article (eg. http://www.newworldencyclopedia.org/entry/Greenhouse_effect). This article appears to be well written but lack references. Juding from it's acceptance and reproductions on the internet most of it appears to be quite sound. I still have had a difficult time finding references to back it up.Veteran0101 (talk) 20:52, 3 September 2008 (UTC)

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

Clarification needed re effect vs greenhouse operation

From my reading, there is a lot of confusion out there because actual greenhouses do not in principle or practice actually employ the real greenhouse effect re reradiation of infrared. A one sentence clarification to this effect in the first para would be helpful imho. Otherwise it takes a lot of reading to get this important point. (Assuming I am not myself just as confused) —The preceding unsigned comment was added by 167.191.250.81 (talk) 18:45, August 20, 2007 (UTC)

Talk:Greenhouse effect confined to history?

The only place to find the Talk:Greenhouse effect since 18 June 2008 is in history. For some reason the Talk:Greenhouse since 18 June 2008 has been disappeared. Curiously enough the last item (at present) is dated 18:45, August 20, 2007 (UTC). I suspect an over enthusiastic archiving attempt. Can we please have items since 1/1/2008 back?--Damorbel (talk) 16:15, 18 August 2008 (UTC)

There hasn't been any talk since June 18... (except for some vandalism that was reverted). So i'm not sure what you are talking about. --Kim D. Petersen (talk) 16:34, 18 August 2008 (UTC)

And this stuff [[1]]--Damorbel (talk) 16:45, 18 August 2008 (UTC)

There is nothing there. Take a look at the history since June 18:

1. (cur) (last) 19:34, 18 August 2008 Damorbel (Talk | contribs) (5,814 bytes (→Talk:Greenhouse effect confined to history?) (undo)
2. (cur) (last) 17:53, 18 August 2008 Damorbel (Talk | contribs) (5,039 bytes) (→Talk:Greenhouse effect confined to history?) (undo)
3. (cur) (last) 17:45, 18 August 2008 Damorbel (Talk | contribs) (4,714 bytes) (→Talk:Greenhouse effect confined to history?) (undo)
4. (cur) (last) 17:34, 18 August 2008 KimDabelsteinPetersen (Talk | contribs) (4,528 bytes) (→Talk:Greenhouse effect confined to history?: what are you talking about?) (undo)
5. (cur) (last) 17:15, 18 August 2008 Damorbel (Talk | contribs) (4,272 bytes) (→Talk:Greenhouse effect confined to history?: new section) (undo)
6. (cur) (last) 16:11, 23 July 2008 Captqrunch (Talk | contribs) (43,506 bytes) (→oceans have warmed 50 percent faster over the last 40 years than previously thought) (undo)
7. (cur) (last) 16:10, 23 July 2008 Captqrunch (Talk | contribs) (43,716 bytes) (undo)
8. (cur) (last) 14:18, 7 July 2008 Landon1980 (Talk | contribs) (66,268 bytes) (rv v) (undo)
9. (cur) (last) 14:17, 7 July 2008 160.79.240.164 (Talk) (104 bytes) (←​ Replaced content with ' pat smell ov piss and luvs nush so much ... i hate him with a passion..... laura sweeney poo'ed herself') (undo)
10. (cur) (last) 00:08, 30 June 2008 Jason Patton (Talk | contribs) m (66,268 bytes) (Reverted to revision 220247366 by William M. Connolley. (TW)) (undo)
11. (cur) (last) 22:48, 29 June 2008 SineBot (Talk | contribs) m (66,689 bytes) (Signing comment by 189.71.49.42 - "") (undo)
12. (cur) (last) 22:46, 29 June 2008 189.71.49.42 (Talk) (66,440 bytes) (undo)

I've remove the archiving bots edits - and the large scale edit that you just made. Which edits do you think is missing? --Kim D. Petersen (talk) 17:37, 27 August 2008 (UTC)

That edit #10 removes the vandalism/unrelated talk in #11+#12. #8 removes #9 (same reason). CaptCrunch removed his own edit in #7 with edit #6. What exactly do you think is missing? --Kim D. Petersen (talk) 17:41, 27 August 2008 (UTC)

On pages with automatic archiving this message is posted "NOTE: Before requesting automatic archiving on an article's talk page or a Wikipedia forum, please establish a consensus that archiving is really needed there." What does it mean?--Damorbel (talk) 16:53, 18 August 2008 (UTC)

Kim D. Petersen, don't you find it slightly embarassing that the last contribution to this red hot topic of Greenhouse Effect has a year gap in the discussion? Or perhaps you share the conviction of many that the time for discussion on these is over? I mean people who visit this article for the first, or possibly more times, might believe that a whole year has gone without anybody taking an interest in it. There are many who wish to see dicussion ended on Man Made Global Warming, Greenhouse Effect etc., so I suggest that a large notice be placed here to draw the visitors attention that all disscussion has been hidden away in the archives, just to avoid giving a false impression.--Damorbel (talk) 18:34, 18 August 2008 (UTC)

The greenhouse effect is not a "red hot topic", Global warming may be. And i think you should take a look at WP:TALK for your discussions on the other subjects. Wikipedia is not a discussion forum. --Kim D. Petersen (talk) 17:37, 27 August 2008 (UTC)

What do you mean it is not red hot? Only for those who think the discussion is over. If you think the discussion is over then the polite thing to do is retire and stop interfering.

The article puports to be describing real physical effects. It is quite reasonable to drawn attention to fundamental weaknesses in the science. Perpetual motion proposals are justly criticised because they breach either the first law of thermodynamics or the second law of thermodynamics, this article describes such a system and similar criticism of the greenhouse effect has a place in a responsible encyclopedia. If that, as the article states, radiation from the cold troposphere can raise the temperature of a surface that is already warmer than the troposphere, it is a weird POV that is strictly your own. If you do not cannot accept the basic physics of this criticism then I suggest you consider your position as an editor. This criticism does not deny climate change or global warming, it merely draws attention to an obvious weakness in the explanation that is clearly incorrect.

I suggest an alternative approach would be to replace the unfortunate passages with some better physics, but stop the meddling with the talk archives, this can only be seen as an attempt to hinder the Wiki process. I have only made one small observation about the shakey physics of the article, do you imagine that is the only one? --Damorbel (talk) 21:15, 27 August 2008 (UTC)

I'm sorry - but this talk-page is not the place to teach or learn physics. (please see: WP:TALK) Your misunderstanding about thermodynamics has been pointed out to you before - and is at this point bordering on tendentious. Can you find a single text-book that supplies your argument specifically about the greenhouse effect - no you can't - because you fail to understand that its the net energy transfer that matters. --Kim D. Petersen (talk) 21:32, 27 August 2008 (UTC)

To cite the article "But the temperature of the atmosphere generally decreases with height above the surface, at a rate of roughly 6.5 °C per kilometer on average, until one reaches the stratosphere 10-15 km above the surface." There is an upwards negative temperature gradient, it gets colder with altitude, the article states "Atmospheric radiation is emitted to all sides, including downward to the Earth’s surface. Thus greenhouse gases trap heat within the surface-troposphere system." this is a very strange assertion that needs a non GH effect reference to support it, are you able to provide one? There is no doubt that heat goes from the warm surface to the cold troposphere, perhaps a good reference will make it absolutely clear. There is no way that this has to be in the context of GH effect, to demand one is merely a ruse to keep the article in possession of a limited group of people who wish to restrict the article to their POV, quite contrary to Wiki policy.

By the way what do you mean by "its the net energy transfer that matters"? The energy the article is talking about is heat, the means of transfer is radiation, all I am doing is pointing the error in direction, no big deal.

I repeat, please change the archiving policy to allow six months of discussion, as it was before May 2008--Damorbel (talk) 07:29, 28 August 2008 (UTC)

Greenhouse gasses

This section contradicts the article Black body. The article Black body states that a black body radiates based on its temperature. This section says that the greenhouse gases in the atmosphere radiate and that non greenhouse gases cannot radiate in the infrared. Veteran0101 (talk) 03:16, 29 August 2008 (UTC)

From blackbody: a black body is an object that absorbs all light that falls on it. The atmospheric gases simply don't fit that definition. Vsmith (talk) 03:29, 29 August 2008 (UTC)

Vsmith, Is Fraser crazy? The Sun Emits black body radiation. What makes the Earth's atmoshere different from the Sun's photoshere? This image: this graphic Shows the black body radiation for 5525K(Sun) and 210-310K (Earth). This section contradicts the image. Non-Greenhouse gases emit blackbody radiation according to their temperature.

http://www.ems.psu.edu/~fraser/Bad/BadFAQ/BadGreenhouseFAQ.html

But, the Earth’s atmosphere does act like the Sun (or at least that part of it we see and which sends us energy). Both the Earth’s atmosphere and the Sun’s photosphere (the part that sends us energy) emit radiation for the same basic reason. Although their temperatures differ, they are both emitting (what is nearly) Blackbody radiation because of those temperatures. And while the photosphere is hotter, our atmosphere occupies a much larger fraction of our sky so we get more energy from the latter.

http://www.ems.psu.edu/~fraser/Bad/BadGreenhouse.html

Does the atmosphere reradiate?

One often hears the claim that the atmosphere absorbs radiation emitted by the Earth (correct) and then reradiates it back to Earth (false). The atmosphere radiates because it has a finite temperature, not because it received radiation. When the atmosphere emits radiation, it is not the same radiation (which ceased to exist upon being absorbed) as it received. The radiation absorbed and that emitted do not even have the same spectrum and certainly are not made up of the same photons. The term reradiate is a nonsense term which should never be used to explain anything. Veteran0101 (talk) 23:32, 29 August 2008 (UTC)

Yeah, he's crazy, but I'm crazier :-)

I wasn't arguing with him at all. What is a major source of the temperature of the troposphere? Could it be the IR radiation from earth's surface - seems likely. The IR is absorbed by greenhouse gases and becomes (fleetingly perhaps) stored energy. O2 and N2 just let this IR zip on by. GG's emit IR giving the tropsphere a temperature to measure. Without the GG's - what would the temperature of the atmosphere be? Kinda low maybe cuz O2 & N2 don't give a shit 'bout IR. What would be the blackbody temperature of a GG-less atmosphere? Do non-GGs radiate IR? Hmm, maybe so, if they are the right temperature (hadn't thought that thru before), but - how do they get to that blackbody IR radiating temperature?...

Your contradict tag was seen as a rather gross simplification considering the content it was slapped on (it also overlapped the image quite messily). Yes, the troposphere can be viewed simplistically as a black body, but the goodies are in the details. ... and on and 0n ... Whatever, cheers, Vsmith (talk) 02:02, 30 August 2008 (UTC)

Vsmith, what really gets me about the article is that is states that the non-GG just sit by and contribute nothing. In fact they receive energy from the GG's and because of their temperature DO emit IR. The section clearly states that non-GG cannot absorb or emit IR. This is only 1/2 true.

My understanding, and correct me if I am wrong, is that the GG's capture the IR just like water captures Mircrowaves in a microwave oven. Once the energy is captured the GG's quickly pass this energy on to the surrounding atmosphere. The surrounding atmosphere GG's and non-GG's as always will emit Black Body radiation depending directly on temperature. The GG's capture the IR and the entire atmosphere emits Black Body radiation depending on temperature.

What browser are you using? At no time, that I can see anyway, has the tag been in front of any image on this page.Veteran0101 (talk) 03:13, 30 August 2008 (UTC)

I shifted the tag up to avoid overlap at 800x600 res. Wasn't a browser problem rather a resolution thing. Also removed the additional reference to talk page.

Not sure 'bout the microwave analogy, there's a significant change in wavelength... but maybe so. The image shows a neat blue "blackbody curve" draped over specific frequency spikes, if as stated, O2 and N2 don't absorb at those λs how can they emit them? But, whether or not the whole atmosphere is a blackbody radiator in the IR is rather irrelevant to the detailed discussion of the physical chemistry of the greenhouse gases involved and seems a minor terminology distraction. But, maybe I'm just blind or full of **it. :-) Vsmith (talk) 13:41, 30 August 2008 (UTC)

Thank you. I will remember the trick. The shift does eliminate the problem. It is however browser dependent. I can increase text size and recreate the effect in opera but not firefox. The text size and browser that I normally use does not have a problem with it.Veteran0101 (talk) 17:55, 30 August 2008 (UTC)

There is a confusion being made here. Blackbody radiation is (approximately) the radiation of molecular interaction. Take any material and get it hot and the constituent molecules will bounce off of their neighbors. Since any accelerating charge will emit electromagnetic radiation (e.g. Brehmstralung), the collisions between atoms (which cause local acceleration of their charged constituents) also creates the emission of small amounts of radiation (in the process essentially converting some of the molecules' kinetic energy to radiation). The frequency and violence of those atomic collisions depends on temperature. For gases, liquids, and some solids, the emission spectrum for atomic interactions is approximately continuous and gives rise to a blackbody shape.

By contrast, atoms and molecules can also absorb and emit light based on electronic transitions within the atom or molecule itself (and molecules can also change vibrational or rotational state). Those transitions are quantized and occur independently of the collisions between a molecule and its nearest neighbors. Greenhouse gases have internal transitions that allow them to efficiently absorb infrared radiation, whereas oxygen and nitrogen do not. As Veteran says, the energy captured by these electronic transitions is often (though not always) subsequently transfered to other molecules by collision, and thus energy captured by greenhouse gases ultimately contributes warmth to the whole atmosphere. However the result of that warmth is that both greenhouse gases and non-greenhouse gases engage in atomic collisions that give rise to blackbody emission.

Incidentally the blackbody process also implies that non-greenhouse gases can absorb some infrared radiation, i.e. by running the process in reverse. If a photon arrives during the collision between two molecules it can sometimes be converted into molecular kinetic energy. However, because that is a three phase interaction (i.e. two molecules + photon must be interacting), the rate of reaction is much lower than absorption of infrared by greenhouse gases which is a two phase interaction (i.e. one molecule of greenhouse gas + photon). In practice, the rate of the three phase reaction is neglible in discussion of the greenhouse effect. Dragons flight (talk) 15:52, 30 August 2008 (UTC)

Thank you Dragons flight. I will re-write the article to make it more accurate. I appreciate your input.Veteran0101 (talk) 17:55, 30 August 2008 (UTC)

Dragons flight, I am curious about your statement above " Since any accelerating charge will emit electromagnetic radiation (e.g. Brehmstralung), the collisions between atoms (which cause local acceleration of their charged constituents) also creates the emission of small amounts of radiation (in the process essentially converting some of the molecules' kinetic energy to radiation)" Are you considering that diatomic molecules also emit/absorb in the infrared? I understanding is that the associated energy levels for diatomic molecules are much lower than for molecules such as CO2 that have substantial charge separation. Further, monatomic gases must produce even less radiation since they have closed shells without any possibility of a dipole.

The common diatomic gases O2 & N2 are transparent even when liquid, I would like to see evidence of what radiation they absorb/emit, let alone blackbody. The often made assertion that all materials emit blackbody radiation is quite incorrect, the whole point of Planck's blackbody spectrum is that charge bound to a nucleus does not emit thermal radiation because its energy is quantized, so, if there is no charge free to accelerate indepedently, there can be no radiation.

I think it is not helpful to introduce Bremsstrahlung as an illustration for charge acceleration in connection with the kinetics of molecules, the proper use of the term is for the encounter of free charged particles (protons, ions etc.), free meaning the energy of the incoming particle has no characteristic value e.g. it is not quantised, thus Bremsstrahlung has a continuous spectrum. --Damorbel (talk) 09:28, 11 September 2008 (UTC)

Damorbel, do you understand the two type of spectra and how they are created?

1. - Line - Created by interactions within atoms/molecules. This is why GHG's absorb and emit in the infrared spectrum.
2. - Continuous - Created by interactions between molecules/atoms. Temperature directly determines the frequency and energy of absorption/emisson. Even non GHG's will absorb/emit dependent solely dependent on temperature. Any substance(even diatomic gasses) will emit/absorb infrared radiation when at the right temperature. Stefan–Boltzmann_law Veteran0101 (talk) 01:38, 21 September 2008 (UTC)

Nice of you react Stefan-Boltzman. Since all radiation comes from accelerating charge I would be most interested to know which charge is accelerating and where in the spectrum it radiates. --Damorbel (talk) 20:35, 21 September 2008 (UTC)

Sorry. It seem neither of us understand what the other is talking about. What is your question? Matter when heated or cooled displays two types of spectra, continuous or line. The line spectrum comes from interactions within the atom/molecule. The continuous spectrum comes the interaction with other atoms/molecules. Veteran0101 (talk) 02:09, 22 September 2008 (UTC)

Veteran, if you do not understand that EM radiation comes only from accelerating charge you will get into difficulties with photons and matter. Line spectra arise where the density of atoms and molecules is low, the photons interact with individual molecules and, because the motions are fairly simple, the spectrum is in lines. As the density increases the atoms/molecules interact with each other and, whatever charge they possess is accelerated by, in the case of gasses, collisions that cause the molecules to accelerate relative to each other. In general adjacent atoms/molecules cause the line spectra of isolated atoms etc. to broaden. Solids are even more complex, for example polished metals hardly reflect or absorb at all because the photons encounter the free electrons that make metals conductors. These electrons are not bound to atoms of metal and do not move with them, therefore they neither emit nor absorb EM energy, it is reflected. What actually happens is that residual oxidation or other noneconducting contamination radiate according to their individual, none metallic, characteristics. The two cases you refer to are part of the more general description of photons and matter, you will perhaps recognise that line spectra and continuous spectra seldom come from matter that is in one state only. --Damorbel (talk) 21:00, 22 September 2008 (UTC)

Damorbel, your explaination is not at odds with what I have just said. Basicly what you are saying is that at low densities line spectra predominate and at high densities continuous spectra predominate. What are you getting at? Diatomic and monatic matter can and do radiate in the infrared, if they are at the proper temperature. Point me to your sources so that I may better understand where you are comming from. Veteran0101 (talk) 02:51, 23 September 2008 (UTC)

The matter I raised was from Dragons flight's contribution above, your intervention didn't address the matter as far as I could see. Dragons flight refers to black body radiation from any material including non GHGs, I questioned this, I still do.--Damorbel (talk) 06:13, 23 September 2008 (UTC)

Research the Explainations of Black body radiation. Dragons Flight is quite correct. Any matter heated to approx 300K will emit continuous spectra in the infrared range. Check out this site http://www.spectralcalc.com/blackbody_calculator/blackbody.php . you will find it interesting. Veteran0101 (talk) 11:21, 23 September 2008 (UTC)

Veteran, you are very wide of the mark, the question is about the radiation characteristics of different materials, gases, solids, liquids etc. You do not appear to be aware of the substantial differences for example your link is utterely irrelevant since it treats emissivity as a parameter to be inserted. I have the impression that this subject is fairly new to you. Since the original question was to Dragons Flight who appears to be unable to answer it, perhaps you should allow the matter to rest there.--Damorbel (talk) 20:20, 23 September 2008 (UTC)

I've removed the tag. There is no contradiction, as the above indicates William M. Connolley (talk) 20:35, 30 August 2008 (UTC)

I've removed:

Although these gasses do not react with infrared radiation at the atomic or molecular level, their absolute temperature does cause the atmosphere to emit Black Body, which at room temperature is infrared radiation

which is arguably technically accurate but its far too misleading. "react with IR" is wrong; "interact" would be OK. As I understand it, the only way they cause the atmos to emit IR is by transferring energy through molecular collision. In this sense, all they are doing is increasing the heat capacity of the atmos. The atmos isn't a black body; there is no need to try to reconcile it with one William M. Connolley (talk) 14:15, 31 August 2008 (UTC)

++++

Thank you Connolley, Dragons flight and Vsmith. I have learned more about greenhouse gasses and the greenhouse effect. This article still needs a lot of work. Do you have any ideas of what I could work on here? I would like to document the processes often quoted in the curent ```Climate Change``` discussions. Thank you all for your time. Veteran0101 (talk) 23:24, 31 August 2008 (UTC)

Reradiate

I reverted the term "reradiate."

I am aware of the fact that some people don't like this term, but the term is accepted and completely well understood in the physics community. There is no ambiguity.

I'm sorry that somebody with a website thinks that the term "reradiate" is a nonsense term, but they're wrong. Geoffrey.landis (talk) 18:48, 29 September 2008 (UTC)

A more substantive problem is that a significant part of the heating of the atmosphere is from non-radiative processes, namely sensible and latent heat flux from the surface. How can the atmosphere "re"radiate energy that it didn't absorb radiatively to begin with? I know the term is used in popular explanations of the greenhouse effect, but it still bothers me that we are perpetuating a misconception. Short Brigade Harvester Boris (talk) 19:41, 29 September 2008 (UTC)

Agree with Boris. What this somebody with a website stuff? William M. Connolley (talk) 20:12, 29 September 2008 (UTC)

"Short Brigade Harvester Boris" wrote: "I know the term is used in popular explanations of the greenhouse effect,"

Let me suggest that, in fact, the term is used in popular and technical explanations of the greenhouse effect and radiative heat transfer.

William M. Connolley wrote: "What this somebody with a website stuff?"

The only citation I can see that anybody have given for deleting the term "re-radiate" or "re-emit" seems to be a website. Can you give me any actual Referenceable sources suggesting that the term shouldn't be used?

Geoffrey.landis (talk) 20:35, 29 September 2008 (UTC)

Errrm, so whats your sooper-source for including the term? And what was the site used for removal? William M. Connolley (talk) 20:51, 29 September 2008 (UTC)

What, do I understand that you're reverting to delete the term without having any actual refererence to provide a reason why you're deleting it, so now you're asking me to provide one to you? Try searching Google (google search for the term "reradiate"), which will give you, for example, the definition from Merriam-Webster: "to radiate again or anew; especially : to emit (energy) in the form of radiation after absorbing incident radiation " or the definition from the American Heritage dictionary: "To emit (absorbed radiation) anew: "Different organic materials in the soil reradiate the sun's heat at different rates" Lori Oliwenstein." or the definition from the Brittanica Student encyclopedia.

Or, for that matter, try a google search for the term reradiation. Geoffrey.landis (talk) 21:06, 29 September 2008 (UTC)

You prove Boris point without introspection. Note key: to emit (energy) in the form of radiation after absorbing incident radiation put into powerful bold. Repeat Boris point A more substantive problem is that a significant part of the heating of the atmosphere is from non-radiative processes, namely sensible and latent heat flux from the surface. How can the atmosphere "re"radiate energy that it didn't absorb radiatively to begin with William M. Connolley (talk) 21:25, 29 September 2008 (UTC)

This article is about the greenhouse effect. It's not about ""non-radiative processes" nor about "sensible and latent heat flux emitted from the surface" (I'm not even sure what he thinks he means by that--how do you "emit" a latent heat flux? If it's latent, by definition, it's not "emitted".) The greenhouse effect is about radiative heat transfer, and therefore radiative heat transfer is what I'm discussing. If this were an article about convective heat transfer in the atmosphere, your comment would make sense. Geoffrey.landis (talk) 22:14, 29 September 2008 (UTC)

Yes, this article is about GHE. Which is inextricably linked to energy xfer through Earth atmosphere. Which happen through many process: radiative only one such. Latent heat also very important; not to neglect. Physicist often over-simplify view of Earth atmosphere but this not correct. Restriction of discussion to only radiative phenomena not possible or permissible William M. Connolley (talk) 22:18, 29 September 2008 (UTC)

Please re-read what I wrote. I never wrote "sensible and latent heat flux emitted from the surface" so I'd appreciate your not putting quote marks around something I did not write. Much less following that up by berating me for writing the thing I did not write ('how do you "emit" a latent heat flux?'). Short Brigade Harvester Boris (talk) 00:29, 30 September 2008 (UTC)

We seem to be having some difficulty communcating. This article is about the greenhouse effect, and the text I had inserted was text defining the greenhouse effect. The greenhouse effect is an effect where atmospheric gasses absorb infrared and then reradiate.

It is true that other means of transferring energy to molecules in the atmosphere also cause them to emit infrared radiation. However, in the section under discussion I was defining the greenhouse effect, not "many processes". Geoffrey.landis (talk) 02:23, 30 September 2008 (UTC)

The greenhouse effect is created by the transfer of energy through the atmosphere in all forms. The leading terms in those energy transfers are radiative processes, but it is incorrect to believe that the greenhouse effect is defined only by absorption and reradiation. Some texts incorrectly describe the greenhouse effect that way, but you have to also include non-radiative energy transfers to have a complete and quantitatively correct understanding of the greenhouse effect. Dragons flight (talk) 02:31, 30 September 2008 (UTC)

Citation, please. Geoffrey.landis (talk) 02:55, 30 September 2008 (UTC)

Google "radiative-convective equilibrium" and take your pick. The classic Manabe and Wetherald paper is good as always, and specifically notes the problems with pure radiative equilibrium (as would result from the simple absorb-and-(re)radiate mechanism). Short Brigade Harvester Boris (talk) 03:14, 30 September 2008 (UTC)

We continue to have a difficulty in communication here. I am specifically talking about the definition of the word "greenhouse effect". You seem to be talking about atmospheric thermal models in general. Yes, of course I am aware that the greenhouse effect is not the only thing that needs to be considered in making an accurate model of heat transfer in the atmosphere. I'm not discussing that here because I'm not discussing heat transfer in the atmosphere in general. I had written a sentence defining the greenhouse effect, which is an effect of infrared absorption. If you believe that the definition of the greenhouse effect does not involve infrared absorption, please give a citation stating this.Geoffrey.landis (talk) 03:41, 30 September 2008 (UTC)

For the second time, I ask that you read what I actually have written. I never said "the definition of the greenhouse effect does not involve infrared absorption." Short Brigade Harvester Boris (talk) 03:46, 30 September 2008 (UTC)

Boris, the conversation here incorporates many people, not just you. If you want me to disentangle precisely what I was responding to, in the context: I attempted to define the greenhouse effect. You deleted the term "reradiate" from the definition I wrote with the comment "not "re-radiate", please -- they absorb, and they radiate". You, along with William M. Connolley, mentioned that the radiated energy could have been originally be transfered in other forms. I challenged this, stating that although energy in general is transfered in many forms, the greenhouse effect is specifically about infrared absorption and reradiation. Dragons flight stated "The greenhouse effect is created by the transfer of energy through the atmosphere in all forms." I asked for a citation for that statement, and stated again that the greenhouse effect refers to the absorption of infrared in the atmosphere, a radiative effect, and does not refer to "transfer of energy through the atmosphere in all forms". You jumped in with a citation stating that understanding all forms of energy transfer is neceessary for accurate thermal models of the atmosphere. This is what I'm responding to: the citation you gave in response to the question I asked in response to the statement Dragons flight gave in response to the statement I made that the greenhouse effect involved infrared absorption and reradiation.

I'm getting annoyed with the tabbing here, so I'm going to de-tab and try to start the conversation, in an attempt to get back to the topic. I am trying to stay to a very narrow topic. I'm not trying to discuss every possible form of energy transfer in the atmosphere. I am simply trying to write a definition of the term "greenhouse effect" that is clear and concise. Geoffrey.landis (talk)

Specifically in the context of writing a simple, one sentence definition of what the greenhouse effect is, could you explain clearly what the objection to the use of the word "reradiate" is (in defining the greenhouse effect --I am not explaining heat transfer in the atmosphere in general)? The original comment to justify the deletion of the word reradiate was: "not "re-radiate", please -- they absorb, and they radiate." I have listed the dictionary definitions of the word reradiate, from Merriam-Webster and the American Heritage dictionary. The word seems accurate. It is commonly used in physics. It is commonly used in explanations of the greenhouse effect. Can you give, perhaps, a citation as to why it shouldn't be used on Wikipedia? Geoffrey.landis (talk) 12:58, 30 September 2008 (UTC)

This link was provided above, which I consider a more reliable source than a dictionary.[2] - Atmoz (talk) 13:35, 1 October 2008 (UTC)

I'm getting to the point where I can do little than just repeat myself. Here's what I wrote earlier: The only citation I can see that anybody have given for deleting the term "re-radiate" or "re-emit" seems to be a website. Can you give me any actual referenceable sources suggesting that the term shouldn't be used?

For comparison, I just added three references-- to textbooks from reputable presses-- citing the use of the word "reradiate" in definitions of the greenhouse effect, and I also footnoted three dictionary definitions. The fact that I limited the references to three is merely because I thought three would suffice; it would certainly be possible to add thirty. If you consider the personal site of the Frasers "more reliable than a dictionary," you should re-read Wikipedia:Verifiability#Self-published_sources.

Unless you can cite a source other than a personal opinion website, I see no reason to not use the term, since it is concise, clear, and accurate. Geoffrey.landis (talk) 13:54, 1 October 2008 (UTC)

I disagree. The term is neither clear, concise, nor accurate, as evidenced by this talk page and the footnote on the article. [3] - Atmoz (talk) 16:42, 1 October 2008 (UTC)

Indeed. But I too can't see much to do other than repeat self. It is worth noting that the term reradiate can be confusing. The photons reradiated are not the same as the photons that were previously absorbed, and may be at different frequencies. is *wrong* (as is the use of the word re-radiate): the energy represented by the photons may not have come from photons at all. But we've said this already William M. Connolley (talk) 18:48, 1 October 2008 (UTC)

Correct that we've said it all before. I've cited sources. You? Geoffrey.landis (talk) 19:05, 1 October 2008 (UTC)

Sources for the definition of "reradiate" don't address the dispute. We aren't bothered by the definition of reradiation, but rather we are bothered by your description of the role that reradiation plays in the greenhouse effect. We have been trying to explain to you that reradiation is only a partial source of the atmosphere's thermal radiation. Hence, it is an erroneous oversimplification to explain the atmospheric thermal emissions contributing to the greenhouse effect solely in terms of reradiation. Consensus here is clearly against you right now; please stop re-adding this material. Dragons flight (talk) 19:28, 1 October 2008 (UTC)

As far as I can tell, the claim that the term "reradiate" is inaccurate is WP:OR, in that there have been no citations adduced to support this view (except for the Fraser website, which I would consider to be opinion, not science, and which adduces a different argument, which is that the term is "nonsense") Geoffrey.landis (talk) 19:59, 1 October 2008 (UTC)

The MedCom ArbComm used "the Frazier website" as a RS.[4] Also from that ruling, it appears you may use the term "reradiate", but only as a metaphor. Your addition does not make clear that the term "reradiate" is being used as a metaphor, and not a physical process. - Atmoz (talk) 20:38, 1 October 2008 (UTC)

Well spotted. Though that was from ArbComm, a higher court William M. Connolley (talk) 20:42, 1 October 2008 (UTC)

The term "reradiate" is not a metaphor. Geoffrey.landis (talk) 20:59, 1 October 2008 (UTC)

Are 4 sources really necessary after this sentence? Thus, greenhouse gases trap heat within the surface-troposphere system. - Atmoz (talk) 03:37, 3 October 2008 (UTC)

It is not clear that four references are sufficient. There is apparently some dispute over the actual definition of what the greenhouse effect is, and references seem to be needed.

On the other hand, I notice six inline citations plus five end-references stating that the "greenhouse effect" in the atmosphere is not the same mechanism as the mechanism of physical greenhouses (this information is repeated in three different places in the article); it's possible that these eleven references might be condensed to fewer. Geoffrey.landis (talk) 13:45, 3 October 2008 (UTC)

The debris of a long-settled edit war. Could probably be pared down now William M. Connolley (talk) 19:14, 3 October 2008 (UTC)

No, long settled [5]. Don't get your war mixed with the old one William M. Connolley (talk) 21:30, 3 October 2008 (UTC)

Ah, I see, you were replying to the second comment, not the first. OK; I deleted my comment; feel free, if you like, to delete your comment as well as this one. Geoffrey.landis (talk) 22:12, 3 October 2008 (UTC)

"The Green House effect" is a phrase that refers to the fact that the Earth's average surface temperature is 14C instead of -18C (or there abouts). Basically, the atmosphere stores heat during the day (using several mechanisms) and then keeps the surface temperature higher at night via IR radiation. The phrase "Green House effect" has nothing to do with how heat gets into the atmosphere, it applies only to the increase in average surface temperature because the Earth has an atmosphere. Approximately 25% of the heat in the atmosphere is from non-IR processes (convection and evaporation). Q Science (talk) 18:52, 30 September 2008 (UTC)

Discussing Reradiation

I had stopped editing the article while waiting to see if the informal request for mediation is going to do any good.

This is a long post-- sorry. It seems that the short discussions of reradiate haven't been useful, so maybe a longer analysis, which tries to address the terminology and analyze the physics may help. I'm putting it in a new section, so I can put in some section headings and try to organize my thinking, but this is in effect a continuation of the previous discussion Geoffrey.landis (talk) 18:35, 5 October 2008 (UTC)

Why is reradiation important?

The problem is that the revised version, deleting the term "reradiate," has also deleted any kind of causality from the explanation of the term "greenhouse effect". The current text says that Greenhouse gases effectively absorb thermal infrared radiation emitted by the Earth’s surface, by the atmosphere itself, and by clouds. They also radiate thermal infrared in all directions." But there's no connection between the first statement-- greenhouse gasses absorb-- and the second-- greenhouse gasses radiate. They are as disconncted as my saying "I play the trumpet, and also read science fiction." Here's a question: if absorption weren't disconnected to emission, why would the absorption of upward infrared have any effect on the ground temperature? The temperature of a body doesn't depend on what happens to the outgoing energy after it's radiated; it's the downwelling radiation that matters. If the absorbed radiation isn't reradiated downward, it has no relevance to heating the planet; reradiation is the only reason that the absorption of upward radiation is relevant.

So, at the very best, I'd say that the current rewrite is bad because it has lost an important causal connection. Geoffrey.landis (talk) 18:35, 5 October 2008 (UTC)

Causality can be included without the term "reradiate", see [6].

Also, there was something of a mistake in that section, which you repeat here. Most of the energy absorbed by greenhouse gases is transferred to other molecules via collision prior to the emission of thermal radiation. Hence it is the atmosphere that radiates in all directions, not just the greenhouse gases. This gets at another reason that "reradiates" is a problematic description of the process since the absorbers are a smaller class than the "radiaters". Dragons flight (talk) 19:19, 5 October 2008 (UTC)

Is physics simplifying? Is that good or bad?

To some extent, this seems to be a fundamental difference in approach between physicist's way of viewing the world and a computer modeler's. The heart of this problem is captured by an offhand statement by Connolley: "Physicist often over-simplify view of Earth atmosphere but this not correct."

That's it right there. What physicists call "simplifying," the computer modelers call "oversimplifying."

The physics approach would be to analyze the problem of heat transfer in the atmosphere by breaking it down into the elementary mechanisms and try to understand and name these mechanisms. The computer modeling approach, on the other hand, is apparently that it's irrelevant to break the problem down into elementary parts; it's all a single complicated system, and a computer model has no need to separate out the various mechanisms from one another; it's just one model, and can be as complicated as you like.

Is simplifying correct? Well, yes. Saying, as Connolley does, that you cannot break the problem into parts and you have to define the greenhouse effect as the entirety of heat transfer in the atmosphere is not useful toward understanding. Although all the energy transfer processes are of course linked, the radiative transfer is the part of the process described by the label "the greenhouse effect". Geoffrey.landis (talk) 18:35, 5 October 2008 (UTC)

I am a physicist. I agree with Connolley that your description is too simple. And no, the greenhouse effect is not just the radiative processes. The greenhouse effect refers to the entire set of processes in the earth-atmosphere system that lead to an increased surface temperature above what would be expected if the Earth and sun were simply in radiative equilibrium with no atmosphere. A large portion of that is attributable to the absorption by greenhouse gases, but that is not the whole story. You can discuss the parts of the energy transfer, including radiation, latent heat, convention, etc., but the term "greenhouse effect" refers to the whole process of recycling energy and not just one of the parts. Its not simply a matter of fostering understanding, it is a matter of being correct versus being wrong. Dragons flight (talk) 19:29, 5 October 2008 (UTC)

From listening to you, I'm beginning to think that the modern world is attempting to redefine the greenhouse effect to be "any mechanism by which an atmosphere increases the temperature of a planet above the blackbody thermal equilibrium". Which would be a pity, since by removing mechanism from the definition, the definition becomes mostly useless-- a statement like "a planetary atmosphere increases the surface temperature of a planet due to the greenhouse effect," would thus becomes a tautology. I don't think that this less useful definition has quite yet taken over, though. By the way, let me note that by the definition you cite, the third paragraph of this article ("The greenhouse effect is only one of many factors which affect the temperature of the Earth. Other positive and negative feedbacks dampen or amplify the greenhouse effect.") no longer makes any sense-- you have defined the greenhouse effect as everything that increases the planet's temperature, so there can't be "other" effects. Geoffrey.landis (talk) 03:30, 7 October 2008 (UTC)

Just as an aside, your (GL) statement above displays a surprising lack of familiarity with how atmospheric modeling (or geophysical modeling in general) actually works. "Break(ing) the problem down into elementary parts" is precisely what we do. Short Brigade Harvester Boris (talk) 19:44, 5 October 2008 (UTC)

Is the term "reradiate" nonsense science?

From the commentary, I can disentangle two proposed reasons to delete the term. First, there was a link to a personal opinion website named "badgreenhouse" that expresss an opinion that the term is "nonsense science." However, this is silly. I spent some time debunking this statement, linking to definitions and to widespread use of the term in physics to show that it definitely is not nonsense, before discovering that (although they linked to the website) in fact nobody commenting here was actually advocating the belief that the term is nonsense, and so addressing the misconception expresed on that site is irrelevant to the conversation. So I will assume, since nobody is asserting this, that addressing the claims of the badgreenhouse website is not relevant to the further discussion Geoffrey.landis (talk) 18:35, 5 October 2008 (UTC)

Is thermal transport by latent heat part of the greenhouse effect?

The only real physics in the discussion so far is essentially encapsulated by "Short Brigade Harvester Boris" in the statement "a significant part of the heating of the atmosphere is from non-radiative processes, namely sensible and latent heat flux from the surface."

This is true, but it is not relevant. The true part is that heat is indeed transferred in the atmosphere by non-radiative processes. The irrelevant part is that these non-radiative processes are not known as "the greenhouse effect", unless you chose to define the greenhouse effect as "the sum total of any and all heat transfer processes in the atmosphere."

This is not a useful definition. The greenhouse effect is the part of the heat transfer that is mediated by absorption and reradiation of infrared radiation by atmospheric gasses-- that is, greenhouse gasses-- it is not the entirety of atmospheric thermal transport. This is not to say that there are no other mechanisms of thermal transport, but only to say that these other mechanisms are not part of the definition of the greenhouse effect. On the other hand, latent heat is a critical factor in the understanding of other parts of atmospheric circulation-- it is a large part of what drives atmospheric motion. So it's not the case that you can ignore it in thinking about the atmosphere- it's merely the case that it's defined otherwise than as a part of the definition of the greenhouse effect.

Short Brigade Harvester Boris does not actually talk about why he thinks that latent heat flux in the atmosphere should be considered greenhouse effect, but let's take that as an example and a chance to examine the physics. Here is the cycle by which latent heat is radiated as infrared:

• (1) Water at the surface of the earth evaporates, in the process absorbing thermal energy and storing it in the form of latent heat, resulting in evaporative cooling of the surface,
• (2) the water vapor rises into higher levels of the atmosphere, carried by convective motion.
• (3) the water vapor condenses into either liquid or solid form, releasing latent heat in the process,
• (4) the droplets or crystals transfer this thermal energy to the atmosphere
• (5) the atmosphere radiates in the infrared; half the radiation is upward, half downward

Look at the image - 62% is down, 38% is up. This is related to the fact that the atmosphere is warmer near the surface and suggests that the atmosphere is nearly opaque at those frequencies. Q Science (talk) 22:06, 5 October 2008 (UTC)

• (6) (some of) the downward portion is absorbed by the ground.

This leads to the question: which, if any, of these processes can be described as "greenhouse effect"? The suggested choice would have to be (5) plus (6).

There are several problems with calling this "greenhouse effect".

One problem is simply the definition. It's not true that any and all mechanisms of heat transfer in the atmosphere is the greenhouse effect.

The second problem is a little more specific; it's that this whole cycle does not actually increase the temperature of the Earth. Step six, the absorption of the radiated energy by the ground, is simply returning (some of) the energy that was originally moved upward by evaporative cooling. The net effect is that the efficiency of thermal transport by latent heat motion followed by radiation has to incorporate the fact that, when the heat is eventually converted into sensible form and radiated, only half of the radiation is released upward. (But, as noted later, that's true regardless of the presence or absence of greenhouse gasses).

The cycle described takes water in condensed form, evaporates it, moves it upward, recondenses it, and then the condensed water radiates. The evaporation and recondensation is actually irrelevant; the net effect is simply that the condensed water is moved upward to radiate from a higher altitude. But in terms of the physics of radiation, there's no difference between condensed water radiating across four pi sterradians, half of which is upward, and condensed water radiating across two pi sterradians-- either way, it's two pi upward. If it weren't for absorption and reemission in the atmosphere, it would make no difference if it were radiating from the surface.

The one difference, of course, is that (due to the partial infrared opacity of the atmosphere) the water radiating from a higher altitude radiates more efficiently. So if the motion of thermal energy in the form latent heat is to be considered at all, it is not adding to the greenhouse effect, but subtracting from it. The motion of energy in the form of latent heat has moved the radiating water above some portion of the greenhouse gasses, and thus it can radiate through less optical depth to space.

So, yes, it's an effect that has to be modeled in understanding atmospheric thermal transport, but no, it's not the greenhouse effect.

A third way of asking the question "is this release of latent heat the greenhouse effect?" is to ask "is the amount of greenhouse gasses in the atmosphere relevant to the retention of this thermal energy?" (This requires an assumption that the term "the greenhouse effect" is defined as "an effect that is related in some way to the concentration of greenhouse gasses in the atmosphere." I'll take to be a given here.) So, does the concentration of greenhouses in the atmosphere change the effective thermal radiation by motion of latent heat? Well, no. If there's a net flux of energy in the form of latent heat Q-dot upward, all of that energy goes somewhere. It's either radiated, or transformed into sensible heat and radiated, but eventually it's all radiated, which occurs regardless of the concentration of greenhouse gasses. The net flux converted to infrared radiation is Q-dot upward regardless of greenhouse gas concentration.

(*A couple of footnotes here: The droplets/crystals themselves also directly radiate in the infrared; only a portion of the infrared radiation of the expressed heat is from energy transferred to greenhouse gasses, since water in either liquid or crystal form is actually a reasonably high-emissivity radiator. Also, some of the infrared radiation originated by the latent heat is neither radiated to space nor absorbed by the ground, but absorbed by greenhouse gasses in the atmosphere and reradiated; this part can be described as greenhouse effect; but it also can be described with the term reradiate.)

Boris goes on to ask, "How can the atmosphere "re"radiate energy that it didn't absorb radiatively to begin with?"

Certainly the atmosphere can radiate energy that it didn't absorb radiatively to begin with. I don't think anyone has ever said it can't. But that's not the greenhouse effect. The greenhouse effect is defined by absorbing and reradiating infrared. Geoffrey.landis (talk) 18:35, 5 October 2008 (UTC)

See my comment two sections up. The greenhouse effect is the system of recycling energy that causes an elevated surface temperature. I believe your definition that limits it to the absorption and emission of radiation is simply wrong. Compare to the effect of wearing heavy clothes. We might term this the "overcoat effect". The overcoat effect keeps us warm by limiting conduction and convection, and trapping radiation. In general some of these processes are more important than others in keeping us warm, but we wouldn't want to say that the overcoat effect should be identified with just one of these processes. In the same way, the greenhouse effect is a set of processes that allow the Earth's surface to retain heat, and it would be misleading to identify it with just one heat transfer process. Dragons flight (talk) 19:43, 5 October 2008 (UTC)

On reflection, I think you are right about part of what you say above. If you could magically turn off non-radiative heat transport, then the Earth's surface would be warmer. In other words the negative impact of non-radiative energy flux from the surface exceeds the extra downward thermal radiation it creates by warming the atmosphere. (Ignoring the issue that evaporation is necessary for maintaining the greenhouse gas water vapor.) However, even so, I continue to disagree with your definition of the greenhouse effect. The radiation from the atmosphere is still a result of the totality of processes affecting the temperature of all the atmosphere's consitutients, and not simply reradiation from the limited portion of the atmosphere that consists of greenhouse gases. To suggest otherwise continues to mischaracterize the origin of the radiation that warms the Earth surface. Dragons flight (talk) 22:37, 5 October 2008 (UTC)

A proposed semi-compromise text

Here is my proposed revised text. I think personally that this has gone too far from "oversimplifying" to "overcomplexifying," but at least one commenter has stated that it's not accurate if non-infrared heat transfer is not mentioned, so this is my draft rewrite to incorporate that comment:

Greenhouse gases effectively absorb thermal infrared radiation emitted by the Earth’s surface, by the atmosphere itself, and by clouds; and reradiate this energy in the form thermal infrared in all directions, including downward to the Earth’s surface, thus heating the surface. (Not all thermal emission is reradiation of absorbed infrared; other mechanisms, including flux of latent and sensible heat via convective motion, also convey heat to atmospheric gasses, which is eventually radiated in the form of infrared. For complete modeling of the greenhouse effect, all heat transfer mechanisms, not just radiative heat transfer, must be accounted for). Geoffrey.landis (talk) 18:35, 5 October 2008 (UTC)

The revision that dragons flight made (19:13, 5 October 2008) does put causation back into the description. I won't say it's perfect, but it is clear and readable. Since several of the (later) references include quotes, it doesn't seem out of place to add a direct quote from the IIPCC FAQ "What it the greenhouse effect" to the second citation; this echoes the deleted wording that I originally used, but perhaps if it's a direct quote, and in a citation footnote rather than in the body, it might be acceptable to the people arguing that the word is taboo to use here. This edit, if acceptable, will suffice for my minimum criteria for an acceptable article. Geoffrey.landis (talk) 03:46, 7 October 2008 (UTC)

First paragraph

The first sentence claims that

The Greenhouse effect refers to the change in the thermal equilibrium temperature

which is defined as

Thermal equilibrium is when a system's macroscopic thermal observables have ceased to change with time.

Since the actual temperature changes, perhaps it should say average temperature instead. Another approach might be to simply use the more correct January 2008 version of the first sentence.

The greenhouse effect is the process in which the emission of infrared radiation by the atmosphere warms a planet's surface.

There are additional problems with the current version of this paragraph. Q Science (talk) 17:16, 1 October 2008 (UTC)

I'm happy with the old version William M. Connolley (talk) 15:41, 6 October 2008 (UTC)

Truth and Lies

There are many ideas about the Greenhouse effect, however most is incorrect asuptions and speculation made by scientists that pay no attention to the REAL facts. most of these scientists are the exact same that made the false "global cooling" theory 30 years ago. If anyone could see through all the mindless conjurings of these scientists, they would see that this climate change is a natural process of heating and cooling between ice ages. what today's environmentalists are doing with the projected heating and climate change is taking about 3 points and making a straight line. I for one think this is unacceptable. There is actually substantial scientific evidence through lab studies that CO2 improves the natural life functions of many kinds of organisms, improving the environment. The light of truth here must shine free and bright, cutting back the shadows and lies that fill our world. Firemonkey09 (talk) 00:17, 8 October 2008 (UTC)

Thanks for your comment. Talk pages are for discussing changes to the article, not for sharing personal opinions. WP:TALK has some useful guidance about talk page use. Assuming your comment is suggesting changes to this article:

• Your argument seems to be against global warming, and not the greenhouse effect. Opposition to global warming is outlined in detail at Global warming controversy and Politics of global warming. There seems little point in changing this article to duplicate these other articles here.
• Wikipedia articles require sourcing. If you're proposing changes to this (or any other article) you will need to find reliable referenced material to back your proposed amendments. It's not about the truth, its about verifiability.

At present you haven't made a case for any changes as you haven't provided any sources. If you wish to do so, be my guest as minority views on an article subject have a place in proportion to their importance and verifiability. Some guidelines on inclusion of minority views can be found here and here. Euryalus (talk) 00:32, 8 October 2008 (UTC)

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? 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.

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