Talk:Greenhouse gas/Archive 3

Misleading statement in intro
Re: "However, an excess of greenhouse gases can raise the temperature of a planet to lethal levels, as on Venus where the 96.5% carbon dioxide (CO2) atmosphere results in surface temperatures of about 467 °C (872 °F)."

The sentence above states that the CO2 in the atmosphere of Venus is responsible for the high temperature. This most certainly is false. Venus can not serve as a reference point in the discussion on the effect of atmospheric CO2 on atmospheric temperatures. blackcloak (talk) 04:50, 1 June 2008 (UTC)


 * This most certainly is false. - is it? William M. Connolley (talk) 18:32, 1 June 2008 (UTC)


 * Remove all the CO2 from the atmosphere of Venus and the temperature would still be lethal (which I'll define as above 100°C). No simulation/calculation necessary. blackcloak (talk) 04:39, 10 June 2008 (UTC)


 * Are you sure? The atmosphere is 96% CO2.  Radiative balance at 0.71 AU with no atmosphere is only 30°C (assuming albedo similar to Earth).  The remaining Venusian atmosphere (mostly N2) would provide some enhancement, but it is unlikely that Venus without CO2 would average above 50 C.  Extremophile bacteria have been observed all the way up to 121 C.  Hence, other factors not withstanding, known organisms could survive the temperature on the surface of Venus if there was no CO2.  Dragons flight (talk) 05:08, 10 June 2008 (UTC)


 * I'm pretty sure you can convince yourself, if you're willing to do (and believe) the calculations. I didn't feel I had to do the calculation, but I'll guide you through a process if you'll do the work and enter it here.  To get started, go to the black body article and compute the temperature of Venus following the procedure shown for the Earth.  Show your assumptions (specifically the Sun's temperature), calculations and results.  Then we'll take the next step if you get the right answer. (Regarding my use of the word believe above, I tend to think your biases will prevent you from accepting the premises and results of this process.  But I'll take you as far as you are willing to go.)  Deal, or no deal?  blackcloak (talk) 07:20, 26 June 2008 (UTC)


 * I already did the calculation and reported my result. If you disagree then you should show your work rather than asking me to walk you through it.  Which, incidentally, I am disinclined to do when you throw around personal attacks.  Dragons flight (talk) 07:43, 26 June 2008 (UTC)


 * I wouldn't have bothered to write if I felt you were close enough to the right answer. I actually don't think you are interested in the right answer at this point.  Suggesting you are biased is not a personal attack, it is a statement of my opinion regarding how open you are to delving into the details of a fairly complicated process, based on what you've written, here and elsewhere.  Obviously I didn't really expect you to take up the challenge.  And accusing me of throwing around personal attacks is a gross exaggeration, and itself a personal attack.  blackcloak (talk) 07:26, 2 July 2008 (UTC)


 * 1366 W/m^2 * (1 AU / 0.71 AU)^2 * ( 1 / 4 ) * ( 0.7 albedo ) = ( 5.67e-8 W/m^2/K^4 ) T^4
 * => T = 302 K = 29 C.
 * I've done the calculation (twice now), you are the one unwilling to provide any math to back up your blind assertions. Dragons flight (talk) 07:40, 2 July 2008 (UTC)


 * If this is going to go anywhere, it looks like we'll have to find a way around WMC. http://en.wikipedia.org/w/index.php?title=Talk:Greenhouse_gas&oldid=234730667 blackcloak (talk) 04:17, 31 August 2008 (UTC)

The main cause of the high surface temperature on Venus is the the massive atmosphere, more than 90 times the Earth's. The lapse rate on both planets is very similar. On Venus the distance to the surface is greater so the temperature is correspondingly greater []--Damorbel (talk) 18:48, 9 October 2008 (UTC)


 * Comparisons to Venus' carbon dioxide don't belong here. Venus has no plate tectonics, no axial tilt, a very long rotational period, no protection against the solar wind blowing away lighter hydrogen, the clouds are made of melted or boiling sulphur, the troposphere is about 65 kilometers high, and the lower 2.5 kilometers of the atmosphere is in supercritical fluid state. One might as well point out that Mars also has over 95% carbon dioxide and never gets above −5 °C.Sln3412 (talk) 21:48, 16 October 2008 (UTC)


 * A massive atmosphere in itself does not cause high surface temperatures. And distance in itself is not related to surface temperature.  Because the atmosphere is highly absorbing across a broad spectrum, an insignificant amount of EM power reaches the surface without being absorbed in, and re-emitted from, the atmosphere.  The nature of the planet's surface is completely irrelevant.  The temperature of the atmosphere is determined solely by the equilibrium established between the incoming solar power and the outgoing "black body " radiated power from the atmosphere.  The solid part of the planet (within the limits of time and thermal conductivity) simply adjusts in temperature to the atmosphere's temperature via normal heat transfer processes. Venus' atmosphere is an oven, with the sun being the source of power. blackcloak (talk) 05:48, 19 October 2008 (UTC)

Blackcloak, surface temperature and pressure are closely related. Look at [Venus], the diagram is not much use, but the table of pressure versus altitude shows a lapse rate comparable with the Earth's. The significant difference is the much higher pressure at the surface of Venus from 90x the weight of gas, thus the temperature is correspondingly higher due to adiabatic compression.--Damorbel (talk) 12:34, 20 October 2008 (UTC)


 * How much of the 25% of the insolation that goes through the 65 KM of troposphere even gets to the bottom 15 KM, and how much of the 96.5% of the atmosphere's carbon dioxide resides in that 33-92 bar bottom 15 KM? What amount of insolation reaches the bottom supercritical fluid 2.5 KM and how does it react?  Even if that is taken into account, there is nothing similar to Earth's atmosphere about that situation.  Sln3412 (talk) 22:24, 22 October 2008 (UTC)


 * Damorbel, I think you're fundamentally wrong because you don't understand that adiabatic heating and cooling are due to CHANGES in pressure (as a function of time). Static pressure can not increase temperature with time (violates conservation of energy).  Increasing the static pressure increases temperature.  Venus does not have an atmosphere that is CHANGING in pressure.  The atmosphere's temperature is for all practical purpose in equilibrium, which means the temperature (profile) is not changing in TIME.  The temperature can still be a function of altitude, while on average NOT changing with time.  Equilibrim means that the amount of energy leaving the planet is equal to the amount of arriving energy (from the sun) absorbed by the atmosphere of the planet.  I stand by my comments. blackcloak (talk) 17:48, 27 October 2008 (UTC)


 * Details aside, greenhouse gases on other planets do not share the same environment nor behave as they do in Earth's atmosphere. --Sln3412 (talk) 19:52, 30 October 2008 (UTC)


 * However you feel about the behavior of greenhouse gases on Venus vs. Earth, they obey the same physical laws. Getting wikipedia participants to be more careful when thinking through the implications of various different physical conditions (such as we know them to be on other planets) is my reason for flagging and correcting errors in understanding of our common physical laws.  blackcloak (talk) 06:19, 31 October 2008 (UTC)


 * The physical laws are the same, the application and results are different. Given Venus' extended high troposphere, sulfur clouds, long rotation and lack of axial tilt, Mars is a much more Earth-like planet.  Ignore the pressure differences between 1, 100 and 9300 kPa.  You still can not compare one planet with 78% nitrogen, 20% oxygen and 1% water vapor to either of the two with 96% carbon dioxide and 3% nitrogen. Sln3412 (talk) 17:35, 31 October 2008 (UTC)


 * While I would disagree with the way you expressed your opinion about comparing one planet's atmosphere to some others, I understand your basic point. My main reason for writing is to express my appreciation of the changes you made in the introduction.  But I do think a further improvement is warranted in the sentence  "Anthropogenic sources of greenhouse gases include modern industrial, transportation, residential, commercial and agricultural processes."  Sources are not processes.  Sources are the result of industrial processes.  As another overall comment, the slight mention of natural causes/sources of greenhouse gases does not convey, right up front, their dominant impact.  Something should be added to provide a more realistic assessment of relative importance, if anthropogenic effects are to be given special consideration in the intro. blackcloak (talk) 03:09, 3 November 2008 (UTC)


 * The intro could be further improved of course. But agricultural processes are one of the anthropogenic sources of greenhouse gases.  Perhaps another word or phrase rather than processes would be better, or something from here http://lwf.ncdc.noaa.gov/oa/climate/gases.html could be integrated into the intro.  The anthropogenic sources are only listing human activities as a subset of the Earth's ecosystem/biosphere.  By available metrics the pre-human levels of greenhouse gases were fairly stable.  It seems unneccessary (at least in the intro) to explain what the "natural" sources are. --Sln3412 (talk) 18:27, 3 November 2008 (UTC)


 * When you've been in and around politics as I have, you learn to read material from the point of view of those who are by nature alarmists, paranoids and fear mongerers. Unbalanced material, especially when it is in a form and place where accuracy and authority are generally accepted, is both detrimental to the individual trying to understand the material and to the reputation of the source of the material. I caution more care.  blackcloak (talk) 19:52, 5 December 2008 (UTC)


 * Hi Blackcloak. On the matter of compression in the atmosphere determining the surface temperature of Venus (or any other gaseous heavenly body) There is a great deal of thermodynamics in what I say. Your argument for "change of pressure" being the cause of adiabatic temperature change is only valid if the gravitational field is left out of the calculation. The usual model is a cylinder with a piston, in this case the pressure is maintained by the walls of the cylinder and changed by the piston. If you ignore gravity the pressure is uniform throughout the contained gas; most piston/cylinder combinations are too small for the mass of the gas to make much difference to the pressure but this doesn't mean it has no effect whatsoever.
 * In reality the gas nearest the source of gravitation (at the "bottom") supports the mass of the rest of the gas in the cylinder, it is thus at a higher pressure, permanently. Thus it is also at a higher temperature than the rest of the gas, permanently. Now the gas attached to Earth and Venus is only there because of gravity, there is no container or piston. The uniform pressure and temperature usually applied to a piston/cylinder combination are inappropriate for an atmosphere. The rise in temperature with pressure in gaseous heavenly bodies can be very great, in stars it raises the temperature so high that fusion of hydrogen occurs, giving stars their phenomenal energy output.--Damorbel (talk) 13:32, 6 January 2009 (UTC)


 * Hi Damorbel. Don't worry, you haven't exceeded my capacity to understand your comments about the thermodynamics involved.  And thanks for taking the time to return to the problem, expressing your understanding of the thermodynamic factors.  I'm not going to quible with your first paragraph, but you are wrong when you say "Thus it is also at a higher temperature than the rest of the gas, permanently."  If you think about it, you know from your daily experience that the temperature at the Earth's surface can change dramatically in a day.  Take the example of desert air in the summer and on cloudless days.  The temperature from the warmest part of the day, say 35C, to the coolest part of the night, say 0C, is about a 10% drop in the absolute temperature in 12 hours.  Now if the sun were to be blocked so no sunlight reaches the Earth, the temperature would continue to lose that 10% every 12 hours, and after about a month, the temperature of the entire atmosphere would fall to the point where all the major gaseous components would condense onto the Earth's surface.  (Because of stored heat in the Earth and oceans, the process might take a bit longer, but still probably less than a year.  There would be water under a surface layer of ice, that would take eons to freeze.)  What you have not revealed by your comments is that you understand that pressure (and temperature) can be functions of altitude, and TIME.  You have to be very careful and distinguish between the two cases.  The piston/cylinder case is one where the time component is key because the compression occurs very quickly compared with the time it takes for equilibration to ambient temperatures.  In the case of the atmosphere, the conditions on a long time average basis are static.  The average atmospheric pressure shows no dramatic changes, so no work is being done on the air to change in time its temperature.  Any temperature changes due to atmospheric pressure changes in time have long dissipated (remember the 12 hour/10% drop scale above).  Finally, you've commented on what happens in stars to support your view.  What is happening there is very different from what happens on a planet.  First the pressure rises so high in the interior of the star that nuclear reactions start to occur which release a tremendous amount of energy.  This energy does not immediately reach the gaseous outer layers, so the interior builds up to very high temperatures.  Via convection the heat move to the "surface" where equilbrium processes allow the star to discharge its thermal energy to space.  (Black body radiation).  As on the Earth, there are no dramatic changes in average pressure as a function of time (of course there will be large changes in pressure as a function of altitude), so there should be no net change in temperature due to the (on average, temporally static) pressure.  The reason the Earth's temperature is a strong function of altitude is the result of thermal energy exchanges processes facilitated by greenhouse gases.  See a little further down in the the discussion under the title "Atmospheric lifetime," my comments dated 29 October 2008. blackcloak (talk) 10:56, 7 January 2009 (UTC)


 * Blackcloak, you correctly identify heat flow arising from the sun (for planets) and heat flow from fusion (in stars) as the source of basic heat energy in the atmospheres of these bodies. All I am doing is pointing out that, where there is a gravitational field (planets; stars) of any significance, then there is an assosciated pressure gradient which gives rise to a temperature gradient in addition to the (uniform) temperature the gas would have in the absence of gravitation. (In the absence of gravitation a container is needed to keep the gas in one place and give it pressure). You point to the variation of temperature over deserts etc., with day and night etc., I could add tropics and poles. The average air temperature in these places is very different; what is not different is the rate of change of temperature with pressure, it is the same over the poles as the tropics, it is largely the same on Venus. Notice I said "rate of change of temperature with pressure", meaning of course change of pressure with altitude. There is a rather confusing concept called lapse rate which describes change of temperatue with altitude. Lapse rate changes with the local temperature (tropics, poles deserts etc.) because the local average temperature differs in these places. The effect of this is the change in the height of the tropopause and as you move from the poles to the equator. To understand the atmosphere properly you must distinguish between temperature change due to different solar input ((deserts, tropics, poles etc.) and pressure (altitude?), both factors are at work simultaneously on a three dimensional planet.  --Damorbel (talk) 21:22, 7 January 2009 (UTC)
 * Damorbel, you use the phrase "rate of change of temperature with pressure" and I use phrases like "pressure is a function of altitude." It is true that temperature varies with altitude like pressure varies with altitude, but that does not mean there is a causal relationship between the two, as you imply.  When I say pressure is a function of altitude, I do mean there is a causal relationship between the two.  Here is how you can know that there is no causal relationship between temperature and altitude:  When you compress air, as in an air compressor, or in a piston/cylinder system, the air heats up.  You dump this air heated air into a compressed air holding tank and can then feel the outside of the tank, which is warm.  If you stop there you would come to the (false) conclusion that a rise in temperature of a gas is DUE to it's increase in pressure.  But, if you come back the next day and feel the pressurized tank, you find that it is at room temperature.  Then you look at the pressure gauge and you see that the pressure is still well above ambient.  The thermal energy was lost to the room, and thermal equilibrium has been established.  The same thing happens in the atmosphere, except the thermal energy is dissipated out into space (via greenhouse gases and IR radiation).  That was the reason for estimating the cooling rate of the atmosphere when there are no driving sources (i.e. the sun).  Now, I can tell that your understanding is so ingrained that you probably are not going to understand what I've said.  My suggestion is that you find a physicist who can take an hour or so to explain a bunch of things to you.  (Don't go to an engineer or a chemist.  They're likely to get it wrong.)  Be prepared to reorganized your knowledge of how the world (of gases) is put together.  I hope that you are not put off by the way I have responded to you.  blackcloak (talk) 03:54, 8 January 2009 (UTC)


 * Blackcloak, your example of air in tank cooling with time does indeed happen but then the conditions of an adiabatic process no longer apply, adiabatic processes are those that exclude change of thermal energy, that is why the temperature/pressure rise/fall as a piston moves in a cylinder is only considered adiabatic if the piston moves quickly (instantaneously). The gas in a cylinder loses (gains) heat through the walls. The atmosphere also loses heat but only by radiation to deep space. If this heat was not replaced by the Sun the atmosphere would cool to about 3K(CMB), in this condition it would be solid and its volume very small. The only reason the atmosphere has any (gaseous) volume at all is the warmth from the Sun. Because of gravity, both pressure and temperature within this volume have a gradient along the direction of gravity. You note the cooling of compressed air in a tank, in your tank the heat is not being continually replaced, in the atmosphere the Sun replaces the heat with day/night and summer/winter variations (to mention a few). The variations do tend to equal out because air heated/cooled in one place changes volume and the resultant change in hydrostatic balance causes heat flow. Describing this flow earned Lars Onsager the Nobel Prize for what are now known as the Onsager reciprocal relations. The difference between your tank analogy and the atmosphere is the absence of (steady) heat flow. Steady heat flow is a condition quite well approximated in the atmosphere and ilustrated by the more or less uniform pressure over the surface. --Damorbel (talk) 10:32, 8 January 2009 (UTC)
 * Damorbel, nothing you say above seems to be wrong, except possibly for the last sentence, depending on interpretation. But even that is so off topic, it's not worth starting up a new train of thought.  There is nothing in your response that hasn't been said before or is particularly relevant.  You missed the point of the tank example- namely the decoupling of pressure and temperature.  But in thinking about your comments and rereading what you've said above, I think I can now present an example that will highlight the difference in understanding that you and I have.  So, I'll propose one last thought experiment before I give up.  Consider a long cylindrical tank, vertically oriented sitting on the Earth's surface.  Let this tank be ten miles high, let it be filled with air, let there be a pressure gauge at the bottom, let the pressure read atmospheric pressure (14.7 lbs per sq in), let the tank be completely enclosed and perfectly insulated and perfectly rigid and have zero thermal conductivity.  And just for grins let's say the initial temperature of the air, from bottom to top, follows some average temperature profile for Earth's atmosphere.  In this thought experiment, there is no mass transport into and out of the cylinder.  There is no possibility of thermal energy, or electromagnetic energy, transfer into or out of the cylinder.  Air is known to have a finite thermal conductivity. The question is what can be said about the temperature profile of the air in the tank after an infinite amount of time.  Specifically, is the temperature of the air constant through the entire volume of the tank, or is there a temperature gradient?  My interpretation of your comments above is that there will be temperature gradient and that such a gradient is due to the Earth's gravitational field.  I claim that the temperature will be perfectly uniform throughout.  A wordy response is not expected or wanted.  Think of this as a multiple choice question:  1) temperature is constant throughout 2) temperature is not constant throughout.  blackcloak (talk) 07:22, 9 January 2009 (UTC)


 * Dead simple, 2). The air at the bottom is compressed by the air at the top, the air at the top is not compressed (much). The air at the top is floating on the air below because it has a lower density (it has expanded and is thus at a lower pressure.) The air at the top has mass and therefore, in a gravitational field, it has the weight (force) to do the compressing. To get the air "up there", work has to be done against gravity (w=mgh), thus the air on top has "mgh" of gravitational energy (imagine 1kg air as 1kg lead at 20.000m height to get an idea of how much energy is involved). The work done to get the air "up there" comes from the expansion of the gas, which cools in consequence, the energy density of the cooled gas remains the same, but it is now split between thermal and gravitational energy. 1kg air at the bottom doesn't have this gravitational energy but it does have the equivalent as heat (to get the extra pressure) so the energy distribution is uniform throughout the column, this is required by the second law of thermodynamics --Damorbel (talk) 11:44, 9 January 2009 (UTC)


 * Thanks for answering. Reminds me of an MIT PhD colleague with whom I had a technical argument.  He never did understand the error of his ways, and was so dismissive about his position that he probably never reconsidered his answer.  And, come to think of it, I remember an EE colleague who described to me an argument he had with a former Dartmouth College EE professor, who, to his (the professor's) credit, after a month of thinking about it, acknowledged his error.  So let's wait a while and see if anybody else has the temerity to answer the question. Any takers?  (Is anyone paying attention?)  blackcloak (talk) 06:02, 10 January 2009 (UTC)


 * Who added the indents? I think one indent per contributor makes it a lot easier to follow a discussion. Blackcloak, there are at least two matters that seem to be at the core of the (mis)understanding, 1) the coupling of pressure and temperature which is standard gas law, dealt with in Wiki here: [adiabatic process] and 2) the effect of gravitation on a volume of gas. This seems to be the real problem and indeed there is not a lot written about it, the best I have found is here by John Baez who is a professor at the University of California Riverside.Could be the guy I am supposed to learn from.  --Damorbel (talk) 11:31, 10 January 2009 (UTC)


 * I added the indents. If you are responding to the material just above your entry, indent.  That way we know exactly what you are responding to.  Providing no/wrong indents makes us look further up to try to figure out the context of your remarks. blackcloak (talk) 05:28, 12 February 2009 (UTC)


 * You found a really good source in John Baez, on a different subject. His notes talk about entropy, a much more difficult subject.  He offers nothing when it comes to our discussion.  blackcloak (talk) 05:28, 12 February 2009 (UTC)


 * It has now been one month and no one other than Damorbel has answered. We can expect this section to disappear into the archives soon.  I guess I should assume no one is reading this stuff.  But if there are readers, certainly no one picked up on the obvious and offered an explanation- that answer 2 allows one to construct a perpetual motion machine, and therefore can not be possible.  All physical processes abide by the Law of Conservation of Energy.  It is a very powerful constraint.  To violate it is perhaps the biggest no-no in physics.  And just to be provocative, it can be used to prove that an infinite God can not exist.  blackcloak (talk) 05:28, 12 February 2009 (UTC)


 * The best example is to simply look at the atmosphere. The troposphere decreases in temperature with height, the stratosphere increases in temperature with height. In the first case, high pressure and high temperature go together, in the other low temperature and high pressure go together. Q Science (talk) 07:15, 12 February 2009 (UTC)


 * The best example of what? Are you actually implying that you think answer 2 is correct?  blackcloak (talk) 08:00, 12 February 2009 (UTC)


 * Seems to me the sentence in question is...dodgy....while kinda accurate, it's also dependant on other factors...a 96.5%CO2 atmosphere on earth, or on pluto...wouldn't have exactly the same effects....you could say that an excess of greenhouse gases could raise the temperature of earth to lethal levels, but that smacks of scaremongering and there's a question over whether it would even be possible in earths situation....possibly a rephrasing (if a source could be found) along the lines of 'a large amount of greenhouse gases could raise the temperatue of the planet by X% of it's temperature without greenhouse gases, which would make earth uninhabitable'.
 * Best bet IMO would be to leave it out. 92.2.124.60 (talk) 16:13, 6 January 2009 (UTC)

I'm not sure how to fix this
re: "It is not possible to state that a certain gas causes a certain percentage of the greenhouse effect, because the influences of the various gases are not additive. (The higher ends of the ranges quoted are for the gas alone; the lower ends, for the gas counting overlaps.)[3][4] "

I'm not sure how to fix this up, since the quote is trying to qualify the foregoing data ranges, but you all might chew on the fact that any average warming has a net amplified effect of introducing more water vapor into the atmosphere, which if the article is correct introduces one hell of a positive feedback factor into the system. If the point made above about only high altitude water vapor being an effective greenhouse gas, then the article is misleading and inaccurate. That's a distinction and clarification which needs multiple cites, imho. Further, IIRC from Science Channel or NatGeo documentaries, hurricanes today are up about 150% in average strength from about two decades ago (perhaps was just one), which isn't showing up yet in gross numbers of higher category hurricane's simply because the scale is logarithmic&mdash;and are further expected to go on gaining relative strength and numbers. Which ties in well with the aforesaid positive feedback. More storms and worse storms.

Another documentary tidbit that caught my attention was the distribution of temperature increase is not uniform, but skewed significantly into the high latitudes... so a few tenths of a degree of mean temperature increase planet wide shows as a significantly higher&mdash;and I'm talking significant orders of magnitude here&mdash;temperatures in the arctic and antarctic regions. IIRC, the (NOAA ?) expert discussing that used a half-degree Fahrenheit increase in global mean temperature translating to nearly 100 times that (43 degrees, iirc) in the arctic average temperatures which he tied into both the observed increases in glacial surface waters, glacier retreats and shrinkages, and glacier advancing speeds.

Lastly, I'd like to reemphasize the points made several times above about heavily weighted verbiage such as "lethal concentrations" vis a vis Venus' atmosphere, et al. Certainly some mention of experts believing Venus is so hot because of the high percentage of atmospheric CO2 is appropriate, but the TONE it creates couched as it is now is patently unacceptable. The point on the preponderance of the article really being focused on Carbon dioxide also needs addressed... particularly in light of the percentage claims of water vapor being a predominate percentage contributor to greenhouse effects. Some better state of balance and coverage, not to say consistency is needed. Best wishes // Fra nkB 08:09, 28 July 2008 (UTC)


 * Water vapor concentrations in the atmosphere rising due to hotter global climate introduce a negative feedback and a positive feedback simultaneously, that have to be considered as two independent effects. H20 molecules re-emit IR radiation, this is true, but clouds are opaque, so they also increase the Albido of the Earth's surface. Hot by night, Cold by day I suppose :P, which of these is dominant integrated over 24 hours is context sensitive, hence your mention of only high altitude water increasing temperatures. —Preceding unsigned comment added by 121.44.161.120 (talk) 15:46, 18 August 2008 (UTC)

Atmospheric lifetime
"It is the net concentration changes of the various greenhouse gases by all sources and sinks that determines atmospheric lifetime, not just the removal processes". Why is this considered for the CO2 but not for the H2O, for which gas it is taken into account the removal time of about 10-12 days? —Preceding unsigned comment added by 189.71.57.224 (talk) 20:02, 6 August 2008 (UTC)
 * It is, actually -- see e.g., Trenberth (1998), Climatic Change, 39, 667-694. Short Brigade Harvester Boris (talk) 18:09, 17 August 2008 (UTC)
 * Be careful with this reference. It is listed as a Viewpoint, which suggests that it is an opinion piece, and has not been peer reviewed.  The text is only available for purchase and not readily available to the average joe.  Here is what you might want to consider.  There are about 30 molecules of H2O in the atmosphere for every molecule of CO2.  A large amount of water moves into the atmosphere (evaporation, hot water vapor emissions) and out (rain) in relatively short periods of time.  Liquid H2O forms readily in the atmosphere and falls because it is denser than air.  The removal of CO2 from the atmosphere occurs through a different process- that of disolving in rain and the surface of the oceans, and at much lower rates, through photosysthesis.  When dissolved in water, it occurs only at the concentration of about 1 molecule of CO2 for every 3000 molecules of H2O.  The reservoir of CO2 in the oceans is about 50 to 100 times larger than the reservoir of CO2 in the atmosphere.  Another key fact to keep in mind is that every carbon atom that oxidizes (combustion or aerobic decomposition) creates a molecule of water, much of that entering the atmosphere along with the CO2. blackcloak (talk) 19:09, 2 September 2008 (UTC)
 * Not true. C+O2 >> CO2, and not a molecule of water anywhere to be seen. Plantsurfer (talk) 19:19, 2 September 2008 (UTC)
 * While you have correctly supplied a balanced chemical equation, the equation does not really apply because such a direct chemical process does not occur in nature between atmospheric oxygen and a pure carbon source. The closest "pure" carbon is underground in the form of diamond, coal (which has lots of H attached) and graphite.  (I know of no biological organism capable of facilitating the oxidation of any form of pure carbon, and using the released energy.)  The Earth has already burned all its naturally available (to the atmosphere) carbon.  If it hadn't our atmosphere's oxygen levels could not be so high. blackcloak (talk) 23:10, 31 December 2009 (UTC)
 * Not true except for long-chain hydrocarbons. Cellulose (general formula ) has its hydrogen in perfect 2:1 balance with oxygen. So wood burning only returns to the atmosphere water that was extracted from it in the first place during photosynthesis. Long chain hydrocarbons on the other hand contain no oxygen, and with general formula H2(CH2)n only a little more than a mole of water is produced on burning for each mole CO2. But for methane that molar ratio becomes 2:1.  And, as I pointed out above, the elemental carbon content of coal of course generates no water on burning. How could it? Now, could you please remind us what the original point of this discussion was, and what exactly all this OR is doing to improve the article? Plantsurfer (talk) 08:33, 29 October 2008 (UTC)


 * You're making some valid points, but missing/ignoring others. When cellulose burns, two important things happen related to greenhouse gases, both of which you failed to recognize.  First approx. one molecule of co2 is formed for every molecule of h2o (6/5 is close enough to 1 for the present purposes), the source of the oxygen, and the original source of the water, since both reservoirs are huge, being irrelevant. Second, the burning sends the h2o into the atmosphere where, as water vapor, it participates as a very significant greenhouse gas.  (The extraction process was at low temperature, the release at high temperature- except where the "burning"/oxidation is by aerobic processes- discussed elsewhere.)  As for your comments about coal/carbon, you might want to read the wikipedia entry on coal.  It implies that the proper way to see coal is as a long-chain hydrocarbon (tho admittedly the hydrogen to carbon ratio is much less than that of liquid long-chain hydrocarbons).  As for the question about the original point, in long chains of discussion there is a great deal of meandering and obfuscation, some of which you're contributing to.  I just respond where I feel points are being made that need correction/context/background and/or an alternative viewpoint.  blackcloak (talk) 20:37, 31 October 2008 (UTC)


 * Yes, true. In a carbon chain there are approximately two hydrogen atoms associated with each carbon atom (oil hydrocarbon, organic molecule).  When the carbon atom is oxidized, the two hydrogen atoms attach to an O atom to form H20.  For carbon alone (even coal has some hydrogen) you're right. Remember most CO2 entering the atmosphere (high 90s in percent) is by natural causes, and is accompanied by the H2O, though much of that H2O is probably traped by soil or water. blackcloak (talk) 02:24, 3 September 2008 (UTC)
 * No, false. Your statement was an absolute (as you noticed yourself). Your last statement forgets that its the flux that matters. The 90% that you talk about, gets sunk into the system again. Its the excess carbon (ie. the carbon that came from outside of the carbon cycle) that remains in the atmosphere. (as opposed to the water). And of course so that we can attribute 100% of the increase in atmospheric CO2 to man. --Kim D. Petersen (talk) 19:45, 27 October 2008 (UTC)
 * So exactly to which of my facts do you object? I don't see where anything I said actually contradicts your statements (my points are about water primarily, yours are about co2)- though I would phrase your points quite differently.  The way I see it, you're comments go way beyond the points I made, and they even enter into the realm of promoting a slanted, biased and personal point of view (and of course that is just my opinion).  As to your points about carbon, it is estimated that we actually don't know where about 30% of the carbon goes, and that unknown sink is some five times the amount of carbon dumped into the atmosphere by man-driven processes.  Until we get a better handle on the sinks we can not say anything definitive about the degree to which the "problem" is attributable to man.  Going back to the point about water put into the atmosphere when carbon chains are "burned," my guess is that there is already so much water vapor in the atmosphere (average of about 1%), without the man-contributed component, that "all" EM radiation in the water vapor absorption bands is essentially fully absorbed.  The argument that water (in particular the man-contributed component) cycles out of the atmosphere so quickly that it can not have a significant impact on warming probably represents a misunderstanding of the nature of absorption when the levels of absorption are nearly complete.  blackcloak (talk) 22:54, 28 October 2008 (UTC)
 * Your absolute statement: "key fact to keep in mind is that every carbon atom that oxidizes (combustion or aerobic decomposition) creates a molecule of water". That was wrong, and you were dodging it in your response. Yes, there is a residual land sink, that we can't pinpoint of about 2-3 GtCy-1. But are you really saying that because we do not know where some of the carbon gets sunk - we can't be certain about emissions? (in your budget - if you are losing money - do you look at your income? :-)
 * Sorry, but I'm right, and I'm not dodging it. So why don't you tell us what happens to the hydrogen after combustion/aerobic decomposition?  I mean if you know something the rest of us don't know, why don't you share your knowledge?  Is this some kind of secret known only to the ordained?  Have you ever taken a course in organic chemistry?  Do you know how to balance a chemical equation?  (If so, here is a trick question:  what are the only two quantities that must be conserved in a chemical equation?  Don't think, just answer.)  As for the 30%, you're reading far too much into my comment.  I'm simply saying you solve the big problems before you solve the little ones.  That's what good engineers do.  I don't know what environmental "scientists" do, but they seem to operate by different rules.  Convince me you can account for the 30% part (sinks) and then I'll start to consider the 5% part (sources).  It's just a matter of priorites.  As for your analogy, if I were to lose 30% in some sort of unaccountable fashion, of course I'd try to figure out where that money was going long before I'd try to figure out how 5% of my income can't be accounted for.  To do anything else would be irresponsible. So forgive me, but it looks to me like your saying this as well. I think you need to be a whole lot clearer.   blackcloak (talk) 04:44, 29 October 2008 (UTC)
 * As for the increase in CO2 being anthropogenic, sorry - but that's as certain as anything can be within science (See other discussions - if anything we are (as Boris says, responsible for >100%)). And finally - its not possible to "max out" absorbsion bands - you just move the altitude of the effective radiating level upwards. (the lower levels emit more to the upper - which then absorbs more). --Kim D. Petersen (talk) 00:28, 29 October 2008 (UTC)
 * I do have plenty to say about your first sentence, but it'll take too long to respond to it now. I'll try to return to this at a later time.  For now, let me address your second sentence. This, too, will take some time, but it is an area where I may be able to move your understanding to a new level.  Here is what happens to upward moving radiative power originating as blackbody radiation at the surface.  To address the point of "maxing out absorption bands" of water, let's first start with the case of radiation leaving the surface at a wavelength in a water vapor absorption band (and not in the absorption band of any other molecular species in the atmosphere) and entering an atmosphere with a very low concentration of water vapor.  Much of the radiation passes through the atmosphere unabsorbed, but some of it is absorbed by water vapor molecules in the column.  In this low-concentration case, and for these wavelenths, the surface emitted (cooling) radiation is not trapped significantly and doesn't add to GW. To complete the case, the absorbed part increases the vibrational energy of some of the water vapor molecules.  The release of the vibrational energy (a certain kind of thermal energy) is a (at least) two part story.  Excited molecules may re-emit the radiation, into 4pi steradians, sending half back towards the surface and half in the direction of outer space.  In either case, reabsorption and re-emission are possible, each step with ever lower likelihood.  But some of the vibrational energy gets transferred via collisions with surrounding air, leaving the original receiving molecule with (usually) less vibrational energy.  Now re-emission is at a longer (usually) wavelength.  And the transferred energy increases the temperature of the surrounding molecules, which will then radiate (eventually) their power at (very long) wavelengths that are unrelated to water vapor absorption bands.  Now in this low concentration case, power at the original wavelength is removed from, and enters the atmosphere, according to Beer's law, which tells us that the outward going power at the original wavelength

drops off as an exponential (assuming the absorbing species concentration remains fixed- which is not the case but can be ignored for now). In the low concentration case, the exponential can be approximated as a linear function and no significant limiting or maxing out occurs. Everything changes in the high concentration case. All the processes described above happen, but they're fully played out at low altitudes. In particular, the exponential profile describing the outward going radiative power as a function of altitude can not be simplified to a (non-maxing out) linear profile. In the high water vapor concentration case, where the original emitting wavelength is in the water vapor absorption band, the outward going radiated power may be for all useful purposes reduced to zero at a low altitude. Re-emission at a lower wavelength is the only remaining process by which the absorbed, now thermal, energy may be lost to space. This is the case where the absorption band is maxed out. So if you add more water vapor to the already high concentration of water vapor, all you do is move the altitude at which the power is "fully" absorbed to a lower altitude. Water vapor above this altitude essentially never "sees" (i.e. does not participate in removing) any outward going radiation at the original emitting wavelength. At this point I suspect I've given you plenty to chew on so I'll stop. blackcloak (talk) 08:47, 29 October 2008 (UTC)

"Remember most CO2 entering the atmosphere... is accompanied by the H2O, though much of that H2O is traped by soil or water". Since this H2O ACCOMPANIES the CO2 and ENTERS the atmosphere, how can it be trapped by soil or water before entering the atmosphere?? Be consistent. Moreover, the CO2 is also trapped by soil and water when it leaves the atmosphere. —Preceding unsigned comment added by 189.71.22.55 (talk) 21:27, 27 October 2008 (UTC)
 * Bacterial decomposition occurs in the soil, and moist soil at that. The co2 is gaseous and while it will be trapped in water, the amount is limited because only a certain level can be achieved.  The water component it generated at ambient temperature and therefore easily incorporated into the water present in the soil. It does not have enough thermal energy to vaporize.  The h2o and co2 are not in anyway tied together, except to the level that co2 dissolves in water.  CO2 won't be trapped in soil (well, dry soil) for any significant length of time.  Co2 dissolved in water may well stay with the water as it enters underground aquifers. BTW you did not quote me exactly; you made a key omission. If I've been inconsistent, it's because I have not taken the time to address relatively tangential aspects of the issues. To repeat, the key point is organic compounds oxidize to roughly equal parts of water and co2.  blackcloak (talk) 22:54, 28 October 2008 (UTC)

Discussion on WHY certain gases have more impact than others.
I'd love to make a request if somebody has the time.

The discussion on why N2 and O2 are NOT greenhouse gases is more informative than the discussion on why CO2, H2O, methane, etc. ARE! The wikipedia article on "Greenhouse effect" has a nice discussion on this topic, but the link is placed fairly out of context, in a sentence about the direction of re-emitted IR energy.

alternatively, I had to click on 'homonuclear diatomic molecule' that was describing chemicals that specifically aren't greenhouse gases just to get a rough explanation of the energy levels associated with translational/rotational/vibrational motion. Then I had to work backwards and assume that a similar process means that greenhouse gases would respond to the wavelengths emitted by the Earth due to its temperature because they have 3 or more atoms in their molecular structure leading to the ability to emit photons via vibrational motion (vs. rotational or translational). Also, the link to "dipole moment" leads to a disambiguation page leading to topics ranging from the distribution of charge within an electron, to the polarity of chemical bonds!

All of this is unacceptable, communicating subtle concepts cannot be so clumsy or open to (mis)interpretation. Notice that the paragraph referencing N2 and O2 refers to concepts only introduced in the article on "Greenhouse effect" and not the current article "Greenhouse Gas".

Another gripe I have with the article is that it mentions that methane is not a significant contributor to greenhouse effect because of its low concentration, but there was no mention that the reason WHY methane has low concentration is because it tends to be less stable than CO2, and breaks down into CO2 after 100 years (off the top of my head). There is currently not enough information given to the reader! should I logically deduce that if CO2 has roughly 2-3x more greenhouse impact than methane but 1/25th the impact per-molecule, then the net release of CO2 into the atmosphere is 50-70 times more than methane released each year?

Also, "It was recognized in the early 20th century that the known major greenhouse gases in the atmosphere caused the earth's temperature to be higher than it would have been without the greenhouse gases." - IMO a link to the article on the "Faint young sun paradox" would be particularly enlightening for those new to the concept of atmospheric insulation.

Unfortunately, I don't have the wiki skills to neaten this up myself. If somebody could follow this up? I assume it's a simple matter for more experienced members of the community.

121.44.161.120 (talk) 15:28, 18 August 2008 (UTC)David Meister - University student, undergrad Physics/Earth Sciences.

edit: my bad, I just found the section on "removal from the atmosphere", so the removal of methane is mentioned, but not until 3 sections after it is mentioned that methane has less effect than CO2. Is this some limitation of the wiki rules in creating articles? or are writers just that disorganized that they can't create a link to something further down in the same article?

121.44.161.120 (talk) 15:35, 18 August 2008 (UTC) David Meister


 * Hi David Meister. Your criticisms of the article are valid, but what you should realise is that this is a work in progress by a bunch of people who don't have too much free time, snd one of the rules of the game is that if you don't like what you see here you don't just criticise it but actively work to improve it. The article, and Wikipedia generally, needs people like you with a critical eye and specialist knowledge of a subject to make an input. Please register and help us! Plantsurfer (talk) 08:58, 31 August 2008 (UTC)


 * Methane lifetime is more like 10y than 100, as you've just found. Its also not insignificant, just samller than CO2. Different molecules radiative properties: having just looked, it seems to me that the discussion of why N2 and O2 aren't, pretty well explains why the others are. The table also shows that CO2 has increased by 100x more than methane, which answers another of your questions, I think. So I think you're complaining that the info is in the wrong order William M. Connolley (talk) 13:46, 31 August 2008 (UTC)


 * The answer is in the heat capacity of diatoms. NO2 and O2 are diatoms, the GHGs are not diatoms. I hope this helps. :) —Will research for food (talk) 19:25, 23 November 2009 (UTC)


 * Clarification: N2 and O2 are Diatomic molecules, diatoms are single celled plants.


 * Also, heat capacity has nothing at all to do with whether a gas emits IR photons. Q Science (talk) 19:46, 23 November 2009 (UTC)


 * While it is not particularly necessary here for this to be understood it is not diatomic molecules that are infrared-inactive (and thus not "greenhouse gases") it is homonuclear diatomic atoms that are infrared inactive, as is stated above.  CO (carbon monoxide) could be a greenhouse gas were it present at significant levels, as could HCl - and any other heteronuclear diatomic molecule that would be a gas at normal temperatures.  Minasbeede (talk) 13:19, 30 April 2010 (UTC)

36%
I have been looking for an alternative source for that figure for a bit, I saw many websites(i.e all of them) giving the 'usual' figures between roughly 60 and roughly 70%, but none I think strong enough to stand up to the rigors I expect certain users would put them through, I realise that this is a very touchy subject for some of you so I'd prefer to find a 'big' source...does the IPCC give out some simple pie-chart type thing for this? I doubt it somehow...

The current 36% figure I reckon does the article no good at all in the eyes of a mildly educated reader, as they're likely to have the same reaction I did when I read it i.e '36%? What bollocks.'....looking at the current source used it appears to be gotten as the result of someone playing with theoretical numbers too much; the nonsense of it can be seen if you examine another result of the juggling on that page...that if water vapour were the only greenhouse effect causing thing in the sky (not even including clouds), the greenhouse effect would be 66% of what it is now....does anyone have a suggestion for a more widely accepted source?92.5.78.172 (talk) 17:10, 5 September 2008 (UTC)


 * Sorry guv you're not making a lot of sense. You don't like the numbers, based on... something; but you have no alternative reliable sources to propose. I guess you could try reading IPCC yourself, though I don't recall seeing it in there William M. Connolley (talk) 20:34, 5 September 2008 (UTC)


 * Off the top of my head, Kiehl and Trenberth (1997, BAMS) is one source. It's right (ah, just a sec...) here. They give figures of 60% for H2O, 26% for CO2, 8% for O3 as clear sky contributions which are in reasonable agreement with the Wikipedia article given accounting for overlap etc. (NB they use the term "radiative forcing" in a different sense from climate change discussions.)  There are other sources out there that probably differ a few percent one way or the other. Basil &quot;Basil&quot; Fawlty (talk) 03:23, 6 September 2008 (UTC)


 * Thanks Basil. I think you misunderstand me William, I 'don't like the number(s) based on' the fact that 36% is completely different to all the figures I've ever seen given for this. I saw many alternative sources (90% of which giving numbers between 60 and 70% with a few outside by a % or 2, and the other 10% giving that 95% figure the skeptics love), but I didn't think any of them would be accepted by, when it comes down to it, you. You are rather well known, even outside wikipedia, for controlling any and all articles into which the message that human beings are causing global warming can be inserted with great zeal. I'm sure you're aware that 60-70% is the more accepted figure, but I'm equally sure that I would not be wrong thinking that you're the one who chose to use the 36-66 figure from that source, and that you have a reason for doing so, therefore I asked if anyone had any 'extra strong' sources, preferably IPCC. I did try searching the IPCC site, but didn't find anything either....
 * I would suggest that not even the author of the article cited now meant that 36% should be taken as a serious answer to the question 'how much of the greenhouse effect is caused by H2O?', and perhaps Basils source would be better. 92.2.214.57 (talk) 18:30, 6 September 2008 (UTC)
 * I'll be glad to discuss radiative forcing and literature references but your personal swipes at William are way out of line. Focus on content and not on personalities, please. Basil &quot;Basil&quot; Fawlty (talk) 20:10, 6 September 2008 (UTC)

Nothing intended as a 'personal swipe' I was merely stating the well known fact that William is the controller of global warming relatied articles, and explaining that I did see alternative sources, but none I felt would be strong enough to meet with his approval to override a source (which I assume) he had previously chosen 92.2.214.57 (talk) 21:15, 6 September 2008 (UTC)


 * Looking at what I wrote I'm hard pressed to see what the 'personal swipe' was, possibly the word zeal carries some undesirable connotations....but either way, if I did offend I apologise. 92.0.46.200 (talk) 02:43, 7 September 2008 (UTC)


 * You don't have to accept Basil's characterization of your comments. I certainly don't.  What you have to understand is that manipulative editors (and no, I am not singling out Basil) bring out the personal attack (I presume a swipe is one small step down from a bonifide passes-the-wiki-test attack.) claim with far too little provocation in order to gain a psychological advantage. Please be aware of the mind games being played.  You are not some grunt to be controlled by power freaks.  Say what you have to say unapologetically, never direct malicious comments at an individual, and point not the finger at the person but at the content/logic of their contributions.  Chances are, you'll generate more heat as you get closer to the truth. blackcloak (talk) 06:39, 9 September 2008 (UTC)


 * Have you considered getting a sidekick with dagger in their name? :)
 * Does anyone object to me replacing the blog (I think it's a blog, looked like one) figures with Basils source? 92.3.162.247 (talk) 15:16, 10 September 2008 (UTC)


 * Yes William M. Connolley (talk) 15:47, 10 September 2008 (UTC)
 * Note that both 36% and 60% are correct, because there are two ways to look at the problem:
 * Start with no greenhouse gases and add water vapor. Compare the LW flux with just water vapor to the LW flux with all greenhouse gases. This gives the 60% figure.
 * Start with all of the greenhouse gases and remove the water vapor. Compare the LW flux with all greenhouse gases except water vapor to the LW flux with all greenhouse gases.  This gives the 36% figure.
 * There are several reasons for the difference, the most obvious being that there is overlap in the absorption spectra of the gases. In other words, in the second approach the other greenhouse gases absorb some of the radiation that would have been absorbed by water vapor so that the apparent effect of water vapor is smaller. The upshot is that we can't say one number is right and the other is wrong. It just depends on how we approach the problem. As our article states: It is not possible to state that a certain gas causes a certain percentage of the greenhouse effect, because the influences of the various gases are not additive. (The higher ends of the ranges quoted are for the gas alone; the lower ends, for the gas counting overlaps.)  Short Brigade Harvester Boris (talk) 16:14, 10 September 2008 (UTC)


 * Thank you Basil and Boris for your replies, apologies for mine being so delayed...real life etc...I can see your point, but I'm far from ecstatic about the way it's being applied. I tend to think that the %ages given for how much of the greenhouse effect that gas accounts for should be referring to the actual situation on earth, rather than theoretical juggling with numbers ones...I'm aware that there is a lot of difficulty giving such figures, hence the vagueness...but as I said previously I have never seen anything like 36% before...everything else I've ever seen has seemed 'happy' to give figures in the 60-70% (or 90+) range...so when I was browsing the article it stood out like a sore thumb. Looking at the source and seeing a not exactly neutral apparent-blog....does not fill me with confidence. I would note that the 36% figure does not, even using the highest figures of every other gas, add up to 100%....perhaps there's some source I'm missing that comes in to account for the gap should water vapour disappear....


 * As wikipedia is mostly meant to reflect what other sources say, I still say it should be changed to the figures that all other sources I've seen give....but failing that, at least get a more reliable looking source...I've had to come to the talk page and have it explained to me and I'm still far from convinced, god knows what other people think....92.2.124.60 (talk) 15:52, 6 January 2009 (UTC)

water vapor and hydrogen fuel cell use
First I should say that I am not a scientist, and most of the technical stuff in the article are unintelligible to me, so any responses need to be really basic. I've actually been waiting since the moon flights for someone to get the idea of using hydrogen fuel cells for cars, but, now that they're apparently the next big thing, I'm getting worried. The article says that water vapor "accounts for the largest percentage of the greenhouse effect", yet asserts that "human activity does not directly affect water vapor concentrations except at local scales (for example, near irrigated fields)." But what happens when millions of hydrogen fuel cell vehicles start adding water vapor to the atmosphere?  Harriet 71.188.232.210 (talk) 16:48, 14 September 2008 (UTC)


 * The short answer is that the extra water will rain back out, and that it's not much water anyway compared to the enormous fluxes in the natural system. (The number of liters in just a day's rainfall are staggering if you work them out.) The long answer is, well, longer... Short Brigade Harvester Boris (talk) 19:10, 14 September 2008 (UTC)

 Thanks Boris; Can you tell me where I can find a long answer understandable to a layman? Since the article mentions local effects, I still envision permanent rain clouds hovering over big cities,(only partially a joke),or stifling humidity at ground level.(Just stand in an alley with a bunch of air conditioners going.) I can still remember coming down from the mountains back in the late sixties, and seeing a smudge of pollution hanging over the road as it snaked across the the desert towards Vegas, (or was it Reno?) Maybe we'll have linear storms.;o). If techno-fixes are still being brought to us by the same outrageously irresponsible mindset that built nuclear power plants, I'm definitely skeptical of easy assurances. These folks thought it was OK to build the plants before figuring out what to do with waste products that will be radioactive for thousands of years longer into the future than all human history. I hope more foresight goes in to the development of hydrogen fuel cells. I suppose the extra water vapor could have a favorable effect, as well: clouds raising the earth's albedo, vapor dimming the sun, or more, and better, water-from-air tech for the dry areas. In any case, I find it hard to believe that the emissions from, not millions, of course, but billions of vehicles, plus probable other power uses, can actually have a negligible effect. Thanks for your patience. ...Harriet 71.188.232.210 (talk) 21:54, 15 September 2008 (UTC)


 * The long answer is, well, unnecessary.... and so is your anxiety about this. The hydrogen for fuel cells will be obtained by splitting natural water (e.g. by electrolysis) into  and . When burned in a fuel cell 2 + >>, returning to the environment only what had already been temporarily removed.  But if you still want to worry about this technology, you might transfer your attention to to the question of how much  is produced to generate the electrical energy required to produce the hydrogen. If that is going to be done primarily with energy derived from fossil fuels the technology will still be contributing to global warming. Plantsurfer (talk) 09:00, 19 October 2008 (UTC)

It is not exaclty correct that the hydrogen used in hydrogen fuel cells will come from water. It is much more likely that the hydrogen will come from fossil fuels, primarily natural gas. You can read the Wiki article here http://en.wikipedia.org/wiki/Hydrogen_production. This is my first time to pst anything on Wiki. —Preceding unsigned comment added by 65.67.110.35 (talk) 21:32, 27 April 2009 (UTC)


 * The anonymous poster is, unfortunately, correct. While, us laypeople expect corporations to do the right thing and use water for H2 fuel cells, oil companies are going to try to hang on, ferociously, and develop tech to extract hydrogen from long chain hydrocarbons--which in effect is a big waste of time and energy rather than just burning gasoline...which is why the process is claimed to be less efficient than burning gasoline. Convenient! —Will research for food (talk) 19:40, 23 November 2009 (UTC)

Atmospheric lifetime, major problem
"However, this ignores the balancing fluxes of CO2 into the atmosphere from the other reservoirs. It is the net concentration changes of the various greenhouse gases by all sources and sinks that determines atmospheric lifetime, not just the removal processes."

The formula given in this section for atmospheric lifetime only has terms that describe outflow (sinks, or removal rates), but the explanation refers to a definition that includes sources (presumably, source rates). This looks like a major problem (ok, maybe it's just an inconsistency based on a misunderstanding) to me. blackcloak (talk) 03:28, 11 November 2008 (UTC)


 * The issue is that the one box model is too simple to be useful for CO2 disturbances. It is largely okay for the other gases listed.  Dragons flight (talk) 04:48, 11 November 2008 (UTC)


 * I devine from your terse comment that the paragraph is really trying to say that the one box model incorrectly predicts a lifetime for CO2, while providing reasonable estimates for other greenhouse gases. This is despite what the author of the cited article has proposed as a means for estimating species lifetimes.  I have to say that physicists would use the sink only definition because it matches their usage of the term lifetime more closely.  Perhaps another term like concentration persistence should be used when both sources and sinks are included in the equation, thereby avoiding confusion over a term that has (may have, if you prefer) a different meaning in another (more rigorous) scientific discipline.  blackcloak (talk) 06:55, 11 November 2008 (UTC)

"It is the net concentration changes of the various greenhouse gases by all sources and sinks that determines atmospheric lifetime, not just the removal processes." Seems on the face of it to be nonsense. Does anyone defend it ? (surely lifetime is according to the formula ie mass / removal rate ?) Rod57 (talk) 05:53, 5 December 2008 (UTC)


 * The statement is correct, though perhaps unclear. The lifetime of an atmospheric anomaly depends of the net removal which is the difference between sources and sinks.  It is especially important for CO2 which has large natural sources and large natural sinks, which almost balance, so that the net removal rate is small even though the fluxes between atmosphere, ocean, and biosphere are large.  Dragons flight (talk) 06:31, 5 December 2008 (UTC)


 * I would disagree to everything and blame the fact that hysteresis is not accounted for in the hydro- and CO2 cycles. Also, my favorite, heat capacities are largely ignored because they aren't a convenient factor.  The hydro-cycle has three phases of matter involved, which means 3 separate heat capacities...meaning 3 different rates of heat flux that are not accounted for. —Will research for food (talk) 19:47, 23 November 2009 (UTC)


 * To what physical quantity are you referring when you say "that hysteresis is not accounted for ..." ? And while you're mentioning perceived problems with the phases of water (I'm guessing it's not handled improperly in the models.), the issues that still seems to be understood very poorly is the impact on EM/thermal power transfer due to the agency of dimers, and probably is not part of most models. blackcloak (talk) 08:47, 25 November 2009 (UTC)
 * You guys should actually read something about how the models work instead of just guessing. Short Brigade Harvester Boris (talk) 18:14, 25 November 2009 (UTC)
 * Since you seem to know something about the subject, what is thought to be the level of error in the radiative transfer calculations due to poor/unchecked models (such as CKD) for water dimers?

Various references:

http://www.sciencemag.org/cgi/content/abstract/300/5628/2078?hits=10&RESULTFORMAT=&FIRSTINDEX=0&maxtoshow=&HITS=10&fulltext=%28water+AND+dimer%29&searchid=1&resourcetype=HWCIT (2003)

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TFN-4T6M85C-2&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=1110430628&_rerunOrigin=google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=c32812112a7112d2e262e009a17e44be (2008)

http://www.sciencedaily.com/releases/2004/02/040225073100.htm (2004)

http://www.agu.org/pubs/crossref/1997/97GL01949.shtml (1997)

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TVR-4PPW79V-1&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=1110440828&_rerunOrigin=google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=1c3ec4c2aae6da449eabfda19e314712 (2008)

http://www.met.reading.ac.uk/caviar/water_continuum.html (2009) "Thus, a deep controversy on the nature of the water vapour continuum still remains unresolved. The atmospheric science community has largely sidestepped this controversy, and has adopted a pragmatic approach. Most radiative transfer codes used in climate modelling, numerical weather prediction and remote sensing use a semi-empirical formulation of the continuum - CKD-model (Clough et al. 1989). This formulation was tuned to available (mostly laboratory) observations in rather limited (far-infrared) spectral regions. The CKD model has served the community extremely well but we lack confidence that its semi-empirical formulation works at wavelength, or in atmospheric conditions, away from those in which it has been tested. This lack of confidence is exacerbated by the recent up-to-date theoretical (Schofield and Kjaergaard, 2003; Daniel et al. 2004; Scribano et al. 2006) and experimental (Vigasin et al. 2000, 2005; Ptashnik et al. 2004, 2005, 2006; Cormier et al. 2005; Paynter et al. 2007) studies that very well correlate and supplement each other, indicating all together the marked water dimer contribution to the water vapour self-continuum in some spectral regions. "


 * To me, the dates and content of these sources suggest we're only able to create heuristic estimates regarding dimers. Doesn't give me a lot of confidence.  The way I figure it, to get to a one degree C error over 300 degrees K means models have to be 99.7% accurate.  blackcloak (talk) 07:04, 26 November 2009 (UTC)

intro as revised by blackcloak, and undone by William M. Connolley
Greenhouse gases are a very small subset of the gaseous constituents of Earth's atmosphere. To a considerable degree, they control the temperature of the atmosphere. At about 1% by volume, water vapor is the most prominent and important of the greenhouse gases. All other greenhouse gases combined make up approximately 0.04% of the atmosphere by volume. Some greenhouse gases are almost entirely from natural sources; others are entirely anthroprogenic. While nitrogen, oxygen and argon are not considered greenhouse gases, they do participate via convection and conduction as a thermal reservoir.

Greenhouse gases are characterized by their ability to absorb and re-emit electromagnetic radiation, particularly in the long wavelength infrared region of the electromagnetic spectrum. The two major sources of electromagnetic energy entering the atmosphere are the sun and the surface of the Earth. Both sources are usually considered to be black body radiators, but at widely different temperatures, and therefore with very different wavelengths associated with their emission peaks. The absorption and re-emission of energy in the atmosphere takes place primarily at low altitudes, and therefore has a strong influence on the temperatures we experience on the surface of the Earth. Clouds and atmospheric dust are significant factors controlling the balance of inward bound (insolation) and outward bound electromagnetic power.

The greenhouse effect[1] is the term used to describe the rise in the atmosphere's temperature due to various competing effects on the flow of electromagnetic energy into and out of the atmosphere. The greenhouse effect is essential to maintaining the temperature of the Earth; without it the planet would be so cold as to be uninhabitable.[2][3]

Natural sources of greenhouse gases are the Earth's ecosystem; anthropogenic sources include industrial, transportation, residential, commercial and agricultural processes. [4]

Venus, Mars and Titan also have atmospheric gases that cause greenhouse effects.

If others finds this a more balanced and accurate way to portray the subject at an introductory level, please state your opinion, make your improvements, and/or otherwise try to override WMC. What he is doing is not funny; it's subverting the very spirit of wikipedia. blackcloak (talk) 01:14, 12 November 2008 (UTC)


 * Blackcloak, posting personal criticism of an editor undermines your case. Your contribution was reverted because it was not an improvement, and I support that revert. If you want reasons for this, here are some examples: For a start, the section opens not with an objective definition, but with a statement that looks like this is going to be POV. Your section is too earth-centred. Greenhouse gases and greenhouse effect are concepts applicable to all planetary atmospheres, as you know. Thirdly, the statement of the identity and origin of earth's greenhouse gases  is a mess, made in two locations, the second specifying a contestable range of sources that omits geological processes, and could be interpreted as equating "earth's ecosystem" with anthropogenic sources. The statement of the process is unclear, includes references to points and concepts which are unnecessary to describe the basic principle and will simply be mystifiying to the uninitiated. The new section is not, in short, either balanced or accurate, is not self-explanatory and is not presented in precise language. The exisitng intro does need to be improved, but let's do it incrementally.  Plantsurfer (talk) 07:56, 12 November 2008 (UTC)


 * Of course I disagree with almost everything you've said. There was no personal criticism, tho it is implied. There is no POV material. The basic structure of the intro was maintained, including the upfront reference to the Earth.  The first paragraph pretty much lays out the "gas" aspect of the topic "greenhouse gas," with an indication of what it is and what it is not.  The original version talks about anthroprogenic components (twice) and yet confuses the matters with non-Earth bodies where there are obviously no such components.  For the typical reader, only the Earth is important anyway.  The original omitted geological processes.  The comment about "earth's ecosystem" makes no sense.  The original talked about both greenhouse gas and the greenhouse effect.  I included that material and clarified some of it.  If you are going to talk about the greenhouse effect at all, you have to understand the movement of EM power up and down the atmosphere, and I made an attempt to indicate how that works.  Certainly it can be improved, but I wasn't about to put that much work into it because I know from far too many experiences that many wiki editors can only see the value of their own work/approach.  As far as incrementally improving the intro, there have been any number of discussion comments about the content and very few attempts to make the improvements.  What you perhaps do not understand is that an hour or two went into rethinking and rewriting the intro.  It came out the way it did for well thought out reasons.  Your, and WMC's, reaction seems to be a knee jerk reaction.  So here is the current version:
 * Greenhouse gases are gaseous constituents of the atmosphere, both natural and anthropogenic, that absorb and emit radiation at specific wavelengths within the spectrum of thermal infrared radiation emitted by the Earth’s surface, the atmosphere itself, and by clouds. This property causes the greenhouse effect.[1] Greenhouse gases are essential to maintaining the temperature of the Earth; without them the planet would be so cold as to be uninhabitable.[2][3] Natural sources are the Earth's ecosystem, and anthropogenic sources include industrial, transportation, residential, commercial and agricultural processes. [4] Venus, Mars and Titan also have atmospheric gases that cause greenhouse effects.
 * And here are the problems with it: 1) talking about the source of the constituents is not needed in a sentence about the constituents, and besides it's included later, 2) the term specific wavelengths is an oversimplified statement of what happens on a macro level, that level of detail being inappropriate for the intro, 3) the by clouds tacked on at the end is not helpful where it is, 4) there is no inclusion of the sun as the major source of energy driving atmospheric heat, 5) exactly what property (absorb and emit are used as verbs) causes the greenhouse effect, and why is the greenhouse effect even mentioned at this point- it assumes knowledge the reader may not have, 6) greenhouse gases do not have the job of maintaining the temperature of the Earth, the temperature is establish as a result of the balance of flow of energy inward and outward, the balance having a greenhouse gas concentration dependence, 7) a long list of anthropogenic sources suggests those are the dominant sources, which they are not, 8) by the way, greenhouse gases don't cause greenhouse effects- the term greenhouse effect is used to describe the end result of energy moving through an atmosphere. No source (sun) means essentially no greenhouse effect.  Greenhouse gases are the acceptors/releasors of energy, i.e. the means (some might use the term vehicle) by which energy is conveyed/transformed.  Perhaps this will give you a better idea why I took on the rewrite and what I considered as I was developing a new version.  blackcloak (talk) 09:41, 12 November 2008 (UTC)

huh????Does anyone other than some weirdo actually get this???I don't! Please explain in a language that people can understand. —Preceding unsigned comment added by 72.65.178.157 (talk) 15:21, 16 November 2008 (UTC)


 * I suppose you would have asked a specific question if you had one. So perhaps it's the process that is unfamiliar.  These should get you started: http://en.wikipedia.org/wiki/Critical_thinking http://en.wikipedia.org/wiki/Critical_reading blackcloak (talk) 08:07, 17 November 2008 (UTC)


 * The poster's point about the article's use of excessively technical language is a very good one, and does not deserve such a contemptuous response. Short Brigade Harvester Boris (talk) 21:28, 5 December 2008 (UTC)


 * The use of the word "article" has a very specific meaning in the wiki context. I suspect I did not read the unsigned comment the way you did.  Either that or you weren't being very careful.  My suggestion to you is to read all relevant material/comments three times (at least one of those times seeking to uncover where interpretation/understanding problems may have arisen) before trying to create a helpful response. blackcloak (talk) 05:22, 7 December 2008 (UTC)


 * Why try and turn an intro on greenhouse gases to something other than an intro on greenhouse gases? Sln3412 (talk) 23:27, 10 December 2008 (UTC)


 * I can just as easily ask why the original contains any discussion of the greenhouse effect. But if I were to answer your question a little more directly, I'd say there would be no point in having an article about greenhouse gases if there were no greenhouse effect.  blackcloak (talk) 09:49, 12 December 2008 (UTC)


 * This article focuses on the gases themselves. It doesn't mean the effect has to be ignored.  The original contains such discussion because the gases cause the effect.  Without greenhouse gases, there would be no greenhouse effect, and vice versa.   That's why the gases are given the name.
 * But to paraphrase you, there's no point in having an article about greenhouse gases that is instead an article about the effect they cause. Nor is the intro the place to get into every point on every topic even slightly related to greenhouse gases. Sln3412 (talk) 22:48, 12 December 2008 (UTC)
 * Thanks for your second paragraph. It tells me you are qualified to be a writer for Glen Beck, and it tells me something about the audience to whom you are trying to appeal. blackcloak (talk) 23:29, 31 December 2009 (UTC)


 * Your earlier 8 points. 1-3 and 5 - The first two sentences of the article are word for word from the IPCC glossary definition of greenhouse gases. 4 - The sun's also the major driver on planets with no atmosphere or no greenhouse gases.  Immaterial.  There is no reason to go into where the thermal IR from the surface, atmosphere and clouds comes from in the intro.  5 - Noted.  Added links to the terms.  6 - "Essential to" maintaining is not "the job of".  Added the word "current" to be more clear.  7 - Mentioning five anthropogenic sources is hardly overwhelming compared to the entire ecosystem.  Especially considering humans are part of the system and therefore anthropogenic but a subset of that system.  8 - The greenhouse effect (change in thermal equilibrium in an atmosphere due to the presence of IR absorbing/emitting gases) certainly is due to greenhouse gases (and clouds). Sln3412 (talk) 23:27, 10 December 2008 (UTC)


 * (1-3,5) The IPCC is a political/governmental organization. It is composed of "experts" (by their own admission), not necessarily scientists (despite what wikipedia says).  They write primarily for mass consumption.  (4) Huh?  (7)The human sources are minor in comparison to the natural sources.  Humans are also responsible for huge greenhouse (carbon) sinks- conveniently forgotten.  And why not add irrigation and cooling towers to the list of anthropogenic greenhouse gas sources.  Why not just include an estimate of the relative contributions from natural(95%) and anthropogenic(5%) sources.  (8) Technically you should say that change in the point of thermal equilbrium is due to change in concentration of absorbing/emitting gases.  But, wherever that thermal equilbrium is, the actual temperature of the atmosphere is determined by the amount of incoming solar power. It has to be that way, because the atmosphere (including the 1% or so that are greenhouse gases), only stores thermal energy (temporarily), and is itself not a net source of thermal power. blackcloak (talk) 09:49, 12 December 2008 (UTC)


 * 1-3,5) Then find a better non-POV and reliable reference with a short glossary definition of what greenhouse gases do and replace it. The IPCC is generally regarded as authoritive in such matters; here is not the place to debate what the IPCC is or isn't.  But as you can see, the first sentence has been edited from a direct repetition of the sentence to "at specific wavelengths within the thermal infrared range."  Along with links to defining electromagnetic radiation absorption and emission, this should quell your dissatisfaction with the IPCC's glossary definition in AR4 being used to open the intro.
 * 4) Are you suggesting people don't know the sun provides all the radiation all the bodies in the solar system get?  That in some way, saying gases absorb heat from the planet needs to be clarified that the surface heated up in the first place because of the sun?


 * Actually, yes. And if you've read the discussion about temperature vs altitude between Damorbel and me, and apparently everyone's failure to recognize a violation of conservation of energy in my thought experiment (should I not include you?), to what other conclusion can I arrive?  Or perhaps you're suggesting that those who contribute to the Discussion section can not be expected to be as knowledgeable as those who go no further than the article itself? blackcloak (talk) 07:57, 10 November 2009 (UTC)


 * 7) Greenhouse gases.  Natural sources are the ecosystem.  The human subset of that ecosystem has sources such as industrial processes.  If you have a reliable non-POV source that 'natural sources without humans' is 1% or 50% or 99%, and 'human sources only' the rest, add it.
 * 8) All good and fine. The greenhouse gases absorb outgoing IR and then emit the energy.  The greenhouse effect is a change in thermal equilibrium in an atmosphere due to the presence of IR absorbing/emitting gases.  That is in no way a claim they are a net (original) source of thermal power.  Look back to 4).  Double the amount of greenhouse gases, or remove them totally.  The amount of incoming solar radiation at the top of the atmosphere is the same.  And you're incorrect.  The actual temperature of a planet's atmosphere is determined by a variety of factors, such as the atmosphere, the planet, the planet's motions through and in space, and incoming solar radiation.  On this one, that includes an atmosphere with greenhouse gases, and humans and their actions. Sln3412 (talk) 22:48, 12 December 2008 (UTC)


 * For all practical purposes, the only source is the Sun and the only sink is outer space. I would guess that all the other sources and sinks basically balance out to a net small (averaged over a year) constant energy (relative to the Sun's contribution), which just contriubtes a net small change in average temperature. To suggest otherwise is just misdirection. blackcloak (talk) 07:57, 10 November 2009 (UTC)


 * "To balance the absorbed incoming [solar] energy, the Earth must, on average, radiate the same amount of energy back to space. Because the Earth is much colder than the Sun, it radiates at much longer wavelengths, primarily in the infrared part of the spectrum (see Figure 1). Much of this thermal radiation emitted by the land and ocean is absorbed by the atmosphere, including clouds, and reradiated back to Earth. This is called the greenhouse effect."AR4 WGI Chapter 1 Page 115 Sln3412 (talk) 23:27, 10 December 2008 (UTC)


 * Let's put on our critical thinking/reading hat and observe what is said and not said in the above quote. Notice the paragraph is about solar energy, or more precisely incident solar electromagnetic power, and about outgoing electromagnetic power. And, although it is not stated explicitly, about black body radiation and the concept of thermal equilibrium.  How precisely and where exactly (other than somewhere in the atmosphere) energy is stored temporarily is not discussed, so the subject of some enabling agent (e.g. a greenhouse gas) is not even mentioned because the nature and source of any enabling agent is IRRELEVANT.  The author has correctly described the greenhouse effect without having to resort to using, or even introducing the subject of, greenhouse gases.  You couldn't have chosen a better quote to make MY point.  Now, in fact, greenhouse gases are an important component of Earth's atmosphere and in Earth's specific case the actual H2O and CO2 content of the atmosphere modulates the electromagnetic power equilibrium, and thereby controls the proportion of incoming solar power that is stored as thermal energy (this affects temperature) in the atmosphere.  blackcloak (talk) 09:49, 12 December 2008 (UTC)


 * You are aware it's from the IPCC, that political/governmental organization composed of "experts", not necessarily scientists, that write primarily for mass consumption?  And the purpose of my quoting it is not to suggest it should be in the intro, much less even in the article.  It's to refute the nonsensical idea that "greenhouse gases don't cause greenhouse effects".


 * I can tell by the way you are arguing your position (repetition without getting very deep into the subject, not responding to specific arguments/points, not challenging the logical progression of an argument, this is not an attack but an observation about your approach) that you need to learn a bit about causality and related ideas. The terms I will be using below can be found in several wiki articles.  I ask you to review these articles with an eye towards developing a better understanding of what is meant by cause and effect, in particular the logical conditions that are placed upon a potential cause in order for it to be considered the basis of an effect:   causality,necessary and sufficient condition.  I think you're trying to say that the presence of greenhouse gases in an atmosphere is a necessary and sufficient condition for a consequent effect called the greenhouse effect, in which there is a change in the thermal equilibrium temperature.  I say this because you never have qualified your statement that one causes the other.  You bind them inextricably.  I say that the presence of greenhouse gases in the atmosphere is a necessary condition for a (greenhouse gas related component to the) change in the thermal equilibrium temperature of an atmosphere.  The presence of greenhouse gases is not a sufficient condition.  Because both the necessary and sufficient aspects are not met, it is illogical to say that greenhouse gases cause the greenhouse effect.  Here is another way to approach this.  Follow the energy (power is the more accurate term, but a less common way to describe this) in a logical progression.  I'll use the path implied by the definition of the greenhouse effect.  Under sunlight, energy (electromagnetic) strikes, and is absorbed by, the earth, that energy heats the surface of the earth (what was EM energy is now thermal energy), the surface consequentially attains a higher temperature, that higher temperature increases the outgoing black body radiation i.e. (predominately long wavelength or infrared electromagnetic) energy flows back towards space (consequently cooling the surface of the earth), some of the infrared radiation is absorbed by molecules (greenhouse gases) capable of accepting infrared EM energy and converting it to thermal energy, the absorbed thermal energy is transferred to nearby, much more massive (non-greenhouse gas) components of the atmosphere, (the greenhouse gas, having given up its thermal energy is rearmed to accept more infrared EM energy,) the temperature of the atmosphere increases and asymptotically approaches a new thermal equilibrium temperature.  At night, the process, again an energy flow process, occurs in pretty much the reverse direction.  So we see by this logical progression, energy is also a necessary condition.  There is no change in thermal equilibrium temperature if there is no energy to drive that process.  No sunlight means no energy, means cooling only, means the thermal equilibrium temperature is essentially zero degrees Kelvin, means no greenhouse effect- no matter what percentage of the atmosphere is greenhouse gases.  Now look back over the energy flow sequence and observe what part is played by the greenhouse gases.  They are an enabler of energy transformation at one particular key point in the process only.  Their concentration governs energy transformation rates only.  One form of energy goes in, another comes out.  No energy is "created" that ultimately can contribute to any change in the thermal equilibrium temperature of an atmosphere.  Back to the necessary and sufficient part.  I claim that we really have two necessary conditions, but I made no argument about what is sufficient.  Here I have to say the definition of the greenhouse effect comes in by specifying the context within which we can make some statement about sufficiency.  The definition of the greenhouse effect contains certain restrictions to the infrared, in effect separating infrared absorbing and emitting components of the atmosphere from the non-infrared-absorbing-and-emitting components. While the definition does not acknowledge thermal energy transfer between the greenhouse gas and non-greenhouse gas components, such transfers are implied because temperature is taken to be a macro observation.  (Of course there are greenhouse-like effects that provide a thermal path for non-greenhouse gases to act like greenhouse gases within Earth's atmosphere, but we'll have to disregard those processes for the purposes of the present discussion.)  So my conclusion is, within the context established by the definition of the greenhouse effect, the two necessary conditions, taken together, form a sufficient condition.  It's kinda convoluted, and long, but that's what it takes to fill in the details behind my argument.  And it points to significant problem with the standard definition of the greenhouse effect because the importance of energy is not sufficiently emphasized.   blackcloak (talk) 05:29, 16 December 2008 (UTC)


 * I am not arguing, I'm sticking to the subject and its context. My position doesn't vary or go deep because I am ignoring the side issues, the details and the points that don't apply.  And I'm only discussing the intro. What is the definition of a greenhouse gas?  A gas that contributes to a greenhouse effect.   A greenhouse effect is a change in the temperature due to a gas that absorbs and emits IR in an atmosphere.   Bodies with no atmosphere, or an atmosphere that can't hold gases that absorb and emit IR, don't have such effects per se.
 * It should have been clear by now that I think you are "ignoring" the "details" that do "apply." Imagine a battery connected to a light bulb via (two) wires.  You observe the bulb light up (analogue of the observable temperature of the atmosphere), and you see the wires as the only thing connected to the bulb.  Do you say the wires are the cause of the bulb lighting up?  I don't, but only because I know that electricity can flow in the wires and that a bulb responds by lighting up when current passes through its filament.  I look for a power source.  And I recognize the wires as the means by which the energy of a power source reaches the bulb.  (And I've already suggested, and you did not refute, the idea that a planetary body with a dead sun would not display the greenhouse effect despite the presence of greenhouse gases.) blackcloak (talk) 06:42, 19 December 2008 (UTC)


 * We're not talking about a solar system with a dead sun. Of course an atmosphere with no power has no effects of any sort, greenhouse or not.
 * As to the metal wires, no, they aren't the cause of the bulb lighting up. (As we know, that would be the electrons interacting with the filament.  The source, a socket, provided originally by a generator, and acting according to the the physics of electomagnetic energy.  However you'd like to phrase the entire process.)  But the wires are the cause of the electricity being transmitted.  Plastic wires or air inside the insulation would not transfer electricity and hence no light.  In somewhat rather like it a way, these gases are the cause of the IR being transformed into heat rather than not transformed, as in an atmosphere without them or one with more argon and so on.
 * Metal reacting to meter long EM and transfering electrons at that same frequency isn't the same as gases absorbing and emitting photons of various frequencies in the mid to far infrared, so the analogy falls apart fairly quickly.  Obviously, the gases aren't the source of the energy, they are the method by which it's converted from the thermal infrared originally provided by the sun.  If transforming thermal IR to heat isn't a cause of warming, I'm at a loss on how to phrase the relationship.  Regardless, the point is that on Earth, Mars, Venus and Titan, as they are, are warmer than they would be if these gases were absent.(Sln3412 (talk) 22:42, 22 December 2008 (UTC)
 * You clearly missed the point of the analogy. blackcloak (talk) 06:17, 4 January 2009 (UTC)


 * The superficial cause/effect is res ipsa loquitur from the definitions. Atmospheres without greenhouse gases have no greenhouse effect, because the (greenhouse) effect is caused by atmospheres with gases that provide those functions.
 * This is a very sloppy way to use words. Effects are not caused by things.  Effects are caused by actions/forces. blackcloak (talk) 06:42, 19 December 2008 (UTC)


 * This doesn't hinge on trying to establish the conditions that must exist for there to be one or more of a sufficient amount of water vapor, carbon dioxide, methane, nitrous oxide, ozone, synthetic gases and the like in an atmosphere, or even trying to describe what is required for an atmosphere in the first place. Nor does it rely upon establishing the physical properties and behaviors of gravity, presure, heat and the like on a given celestial body.  Or explaining the kinetic and chemical properties of nitrogen and oxygen and anything else.  This also isn't a defintion or article about thermal transfer or atmospheres or the behavior of gases in general.
 * The transfer of thermal energy is the root idea. If there is an immediate "cause" for the change in the thermal equilibrium temperature, as the term is used in the description of the greenhouse effect, it is that the atmosphere receives or releases its thermal energy.  The means, or enabling agent, is greenhouse gases.  Not only is "cause" the wrong word, the phrase "the cause" points a finger at one "agent" (for lack of a better term). blackcloak (talk) 06:42, 19 December 2008 (UTC)
 * I believe the root idea moreso is the reason for there being a greenhouse effect. The (greenhouse) effect itself is an overall warming, in this case by hindering (absorbing, transforming, impacting, reacting to) the release of outgoing radiation.   Like the warming in a greenhouse by hindering the process of convection.  Greenhouse gases are so named because they are gases that hinder the release of outgoing radiation, resulting in the behavior of the atmosphere being warmer through a number of processes, starting with the gases thermalizing the IR.    The subject is certainly quite constrained as to scope.  A celestial body that is warmer due to gases reacting to EM at 3-20 micrometers is colder with those gases removed.  Without the gases, there is less thermal energy in the atmosphere.   I don't know how else to phrase it or describe it or explain it.  So I'll quit now.  Sln3412 (talk) 23:44, 22 December 2008 (UTC)
 * You really needn't keep repeating yourself. As I see it the issue is not the underlying physics, the actual nature of the greenhouse effect or anything having to do with the nature of greenhouse gases.  The problem is the specific WORDS (and phrases, and descriptions of how things are (inter)connected) that are used to describe precisely, and in as elementary a way as possible, what is going.  At its most basic level, you and I simply do not share, for starters, a common understanding of the word "cause."  We can not expect to reach any mutually acceptable wording/phrasing when such fundamental differences separate us.  Now, to temper this just a bit, I have been astounded, over my career, on a few occasions by the radically different interpretations (connotations) of words that highly educated (JDs, PhDs to be more specific) individuals can have.  It can be like night and day- both parties left shaking their heads.  And at those levels, there are, in practice, no arbitrators.   blackcloak (talk) 06:17, 4 January 2009 (UTC)
 * If you want more in this article about the presence or absence of transient charge separations, dipole moments, collisionally excited vibrations and the like, I suggest the article on the effect as a starting point to add to the body of the article here. Or add a section in the body on the requirements for an atmosphere to have IR absorbing and emiting gases in it if you're so keen about it. Sln3412 (talk) 22:04, 17 December 2008 (UTC)


 * I'm really only trying to get the intro straight. A lot a readers will stop there, so they should get enough correct information up front to understand the reasons the term is useful. blackcloak (talk) 06:42, 19 December 2008 (UTC)
 * I'm satisfied the intro is correct and descriptive enough to be clear that these gases reacting to thermal IR causes additional warming that wouldn't be there without the gases. Sln3412 (talk) 22:42, 22 December 2008 (UTC)


 * Regardless, you might have had a good point there. Except that the paragraph (an excerpt, only, from the intro, only, to FAQ 1.3 (pages 115 and 116) in AR4 WGI Chapter 1, whose text then goes heavily into greenhouse gases, by the way) is about the greenhouse effect.  It's not about greenhouse gases.  Or in other words, those details on the greenhouse effect aren't germane to a discussion of greenhouse gases.
 * Perhaps you can put on your critical thinking/reading hat and realize an essay on thermodynamics, atmospheric behaviors, the greenhouse effect, human contributions to climate, and the like, doesn't belong in an intro to an article on greenhouse gases. Hence, it was removed.  A clear cause/effect relationship with an established directionality.
 * Your other pertinent points seem to have been addressed. Now on to the rest of the article, and that first graphic.  Sln3412 (talk) 22:48, 12 December 2008 (UTC)
 * You have made quite a number of comments above. I'll respond to them as I find time.  For now, I'll say the intro has improved, but I would like to see further changes, and I want to bring up again the second sentence.  Here are the current first two sentences: /Greenhouse gases are gaseous constituents of the atmosphere that absorb and emit radiation within the thermal infrared range. This property causes the greenhouse effect.[1]/.  The problem I have is that the words "This property" should refer to a previously mentioned "something" (i.e. a noun) that could be identified as a property in order for the sentence to make logical (and easy-to-understand) sense.  To make any sense of it at all, you have to go back and infer a property from the words in a long phrase.  Anyone who reads that second sentence SHOULD be confused, the way it is written.  I'll get to the "causes the greenhouse effect" issue later.  How can we get the content right, if we can't get the structure/logic right? blackcloak (talk) 07:30, 15 December 2008 (UTC)
 * I agree with you about the sentences. Once the original first sentence of the glossary defintion is edited like that, the second sentence needs to be changed.   Something along the lines of "These reactions of the gases to thermal infrared radition are responsible for the greenhouse effect, that is, a change in the planet's thermal equilibrium temperature due to the presence of such gases."
 * At least there's the beginnings of a meeting of the minds. Unfortunately even a basic understanding requires a little more detail.  The "thermal equilibrium temperature" is of the whole atmosphere, not just the 1% or so of greenhouse gases.  The greenhouse gases act like a trickle charger for a huge battery (capacitor if you prefer), and a trickle discharger for the (thermal) energy stored temporarily in that battery (atmosphere).  It is the changing amount of (temporarily) stored thermal energy that moves the equilibrium temperature to some new value. In other words, the non-greenhouse gas components of the atmosphere (o2 and n2) have a huge affect on reducing or moderating the daily excursion of temperature the atmosphere would feel if the o2 and n2 were not present.  It might be correct to say that the "very long term average (over years) thermal equilibrium temperature is shifted slightly (something like 20C out of 260C, and while the temperature change can be slight on an absolute scale, the impact can be great) due to the presence of greenhouse gases in Earth's atmosphere." blackcloak (talk) 21:28, 15 December 2008 (UTC)
 * As far as the cause/effect, if the definition of the greenhouse effect is such that the effect relies upon the presence of such gases, then a new equilibrium depends upon the gases and their behavior. I am unconcerned about how specifically the relationship is explained as long as it's clear, concise, on topic, NPOV, NOR, referenced and such.  No need to argue with me about the defintion of greenhouse gases or effect, or about qualifying or quantifying either. Sln3412 (talk) 20:38, 15 December 2008 (UTC)
 * This article isn't the place to discuss or attempt to explain how to quantify thermal equilibrium at all, much less in an introduction. The effect is the change of equilibrium, the gases make it possible.  The point here is that in two theoretical atmospheres that are exactly the same otherwise, one with such gases is warmer and one without them is colder.   Sln3412 (talk) 20:47, 17 December 2008 (UTC)


 * After reviewing the comments above, I'm prepared to present an alternative intro. Here I'm sticking to just the basics, concentrating on greenhouse gases, but include a second paragraph to show where the term greenhouse effect comes in.
 * //Greenhouse gas(es) is the term used to collectively describe the molecular species in a planetary atmosphere that dominate the acceptance and release of electromagnetic energy in the thermal infrared range, via absorption and emission processes, and the acceptance and release of thermal energy with the atmosphere via heat transfer processes. The concentration, composition and temperature of the greenhouse gas component of an atmosphere, along with the level of incoming solar radiation, governs the rate at which the atmosphere may change its long term average thermal equilibrium temperature.
 * The phenomenon whereby the average thermal equilibrium temperature of a planetary atmosphere is modulated, under the influence of a source of energy (e.g. the Sun), by the energy transfer and transformation properties of greenhouse gases, is called the greenhouse effect.//
 * While a bunch more ideas could be added, the above describes the basics and all that is really needed in an intro. Of course, there would be many links to other articles. blackcloak (talk) 19:00, 16 December 2008 (UTC)
 * This says much the same thing as the present intro except that it is far more verbose and sesquipedalian. (It's also ungrammatical but that's a relatively minor point.) Sorry, but I don't see it as an improvement. Short Brigade Harvester Boris (talk) 21:13, 16 December 2008 (UTC)
 * I agree, not an improvement. (Although verbose and sesquipedalian is a rather wordy and long-wordy way to put it.) The effect is an analogy about an area warmer due to some process, it's not all that difficult to comprehend. That goes in the other article, anyway.  As it stands, the intro is short and to the point. The outline: These gases react to thermal energy.  This is basically the reason for the greenhouse effect.  Without these gases, it would be much colder.  Earth isn't the only planet with such gases and an atmosphere different due to them.  Sln3412 (talk) 20:47, 17 December 2008 (UTC)
 * Greenhouse gases are responsible for heating the atmosphere and for cooling the atmosphere. Increasing the proportion of greenhouse gases in the atmosphere increases both the rate of heating during the day and the rate of cooling during the night. blackcloak (talk) 01:39, 24 February 2009 (UTC)
 * Actually it says a lot more than the present intro. It is no more verbose than it needs to be. (Drop any phrase and you'll lose valuable content.)  Finally, it is grammatically correct, although perhaps it is more complicated grammatically than it should be. (There is one spelling error.) If you think there is a grammatical error, you should point it out so that each of us may have the opportunity to evaluate your capacity for making observations about grammar. blackcloak (talk) 01:39, 24 February 2009 (UTC)

Solar hot carbon
Has anyone heard of solar hot carbon? Is this a real thing? Notable? ChildofMidnight (talk) 03:18, 21 November 2008 (UTC)


 * Never heard of it...but I haven't read all sci-fi yet. —Will research for food (talk) 19:51, 23 November 2009 (UTC)

First graphic
It seems out of place to start an article about greenhouse gases by a chart showing the increase in concentrations of any single gas, even the second most prevalent/highest forcing one. The graphic in the greenhouse effect article seems more appropriate even. But neither is fantastic.

Isn't there a better image on greenhouse gases in general?


 * Moved graphic out of intro, as that industrial age carbon dioxide levels one is not indicative of greenhouse gases themselves or their impact on the climate.  It's in the Natural and anthropogenic section now.  It is probably better off in the Anthropogenic greenhouse gases section, if it's meant to illustrate the change since industrialization started, or maybe Greenhouse gas emisssions.
 * If there's a graphic in the intro section, it should be a graphic showing how the gases work in general or what they do.Sln3412 (talk) 21:11, 15 December 2008 (UTC)

Role of water vapor
I reworded a section for clarity and also to indicate that climate models are based on assumptions. Michael H 34 (talk) 19:04, 2 January 2009 (UTC) Michael H 34


 * Actually you introduced a major factual error, which was to state that water vapor feedback is assumed in climate models. Short Brigade Harvester Boris (talk) 19:17, 2 January 2009 (UTC)


 * "An increasing poleward moisture flux with increasing temperature is explicitly assumed or is implicitly generated in most simple energy balance climate models in which one tries to include the poleward moisture flux (e.g., Nakamura et al. 1994) and has been remarked upon in GCM global warming simulations since the inception of this field (Manabe and Wetherald 1975). It is reassuring but not surprising to find this behavior in the comprehensive AR4 models as well."

I do not agree that what I wrote was a major factual error, but I see your point also. Let's fix it. Michael H 34 (talk) 20:09, 2 January 2009 (UTC) Michael H 34


 * Oh, I see now -- you must have meant things like simple energy balance models or EMICs. I note your latest change, and will tweak it momentarily. Have a look. Short Brigade Harvester Boris (talk) 20:26, 2 January 2009 (UTC)


 * I must be missing something. This positive feedback is assumed in simplified climate models, might be of interest in a page about climate models, but why is it of interest in a page about GHG? William M. Connolley (talk) 20:40, 2 January 2009 (UTC)


 * I'd be quite happy to leave out the discussion of models and simply state that water vapor feedback amplifies the changes caused by long-lived GHG. But if models are mentioned at all then it's important to clarify that WV feedback is not "assumed" in GCMs (as often is incorrectly stated). Short Brigade Harvester Boris (talk) 20:49, 2 January 2009 (UTC)
 * Agreed. I don't think the recent "clarifications" are any improvement; of these two I prefer the former William M. Connolley (talk) 20:56, 2 January 2009 (UTC)

I like the improved version by Short Brigade Harvester Boris. Michael H 34 (talk) 00:43, 3 January 2009 (UTC) Michael H 34

"This and other basic principles indicate that increasing water vapor concentrations in warmer air will amplify the greenhouse effect created by anthropogenic greenhouse gases while maintaining nearly constant relative humidity. Thus water vapor acts as a positive feedback to the forcing provided by greenhouse gases such as CO2."


 * Wouldn't positive feedback be in a closed system where water vapor responds in the same direction as the anthropogenic greenhouse gases and amplifies the greenhouse effect? As described, this doesn't appear to fit the definition.  Sln3412 (talk) 23:05, 9 January 2009 (UTC)

I'd quibble with this section on water vapour:- "The Clausius-Clapeyron relation establishes that air can hold more water vapor per unit volume when it warms. This and other basic principles indicate that any warming associated with the increased concentration of the other greenhouse gases also increases the concentration of water vapor as well."

I understand the basic point you're making but I don't think the Clausius-Clapeyron relation establishes that at all. There is no effective limit to any gas concentration in the air, whether it be nitrogen or water vapour. My understanding was that the concentration of water vapour in warm air is entirely a function of evaporation, not of some inherent property of air to absorb it. Warm air can be arid.

Sorry for the quibble but this paragraph seems to perpetuate the enduring myth that air is some kind of solvent or sponge, with a specific limiting capacity to absorb water vapour. That water vapour condenses at its dewpoint temperature or that clouds form as air containing water vapour cools are unrelated to any property of the air itself. I found these pages useful http://www.ems.psu.edu/~fraser/Bad/BadClouds.html http://www-outreach.phy.cam.ac.uk/camphy/cloudchamber/cloudchamber1_1.htm Boro Nut (talk) 17:59, 7 February 2009 (UTC)


 * Those two websites are very helpful. I consider them required reading for understanding evaporation, condensation, and cloud formation.  The two pages referred to in the first site are also well worth reading.  blackcloak (talk) 08:57, 13 February 2009 (UTC)

On a related issue, it is stated that "This positive feedback does not result in runaway global warming because it is offset by negative feedback, which stabilizes average global temperatures. One primary negative feedback is the effect of temperature on emission of infrared radiation: as the temperature of a body increases, the emitted radiation increases with the fourth power of its absolute temperature." Technically this is a stabilizing nonlinearity and not a feedback. You can't have a net positive feedback at low levels, and end up with a stable system at high levels without the presence of a stabilizing nonlinearity. Clt510 (talk) 19:19, 24 March 2009 (UTC)

Analysis of GHG sources
[Grist] has an article on new compilation and consolidation of sources of GHG's. The full data is presented in a [Google Doc]dinghy (talk) 01:17, 14 January 2009 (UTC)

Intro ref to "IPCC conclusions" removal
An article on greenhouse gases is not the place to super-summarize what the reports comissioned by the IPCC suggest, even if it wasn't WP:OR. Such paragraphs are often interpreted according to key words like this:

"The {IPCC}...concluded that increased greenhouse gases from human activity are causing...global warming..."

As a reminder, "you must cite reliable sources that are directly related to the topic of the article, and that directly support the information as it is presented." The paragraph did neither.

What the reports conclude is that "Changes in the atmospheric abundance of greenhouse gases and aerosols, in solar radiation and in land surface properties alter the energy balance of the climate system." and "The understanding of anthropogenic warming and cooling influences on climate {leads} to very high confidence that the global average net effect of human activities since 1750 has been one of warming."

The rest of the article covers these as appropriate to the context of greenhouse gases. Sln3412 (talk) 17:51, 14 January 2009 (UTC)
 * The current intro ignores the issue of climate change and gives the misleading impression that greenhouse gases are only a source of good outcomes for the planet. The Scientific opinion on climate change and the Intergovernmental Panel on Climate Change in its Fourth Assessment Report reports makes clear that this is almost certainly not the case. I am happy that my wording might not be the best summary, but the intro is currently misleading and ought be fixed. Do you have some suggestions of better wording which would make the intro less misleading? dinghy (talk) 00:18, 15 January 2009 (UTC)


 * It's an intro. To an article about greenhouse gases. That is, gases that react to outgoing infrared radiation.  So I suppose you could say it 'ignores' everything else but that, like the the way models treat clouds, how to bake a cake at high altitude, satellite telemetry calculations, or radiosonde deployment instructions.   As far as being misleading, the intro isn't the place to discuss increased levels of specific types of GHG and what they probably result in, any more than it's a place to detail the nuances how the GHG interact with the atmosphere and each other.   This is not an article on gas flow dynamics > the greenhouse effect > the enhanced/anthropogenic greenhouse effect > climate change/global warming.  Discussions of matters such as climate change attribution and global mean temperatures like in AR4 WG1 SPM pages 10-12 belong in the specific articles this one links to. Sln3412 (talk) 22:15, 15 January 2009 (UTC)


 * The current amount of greenhouse gases in the atmosphere is good for life on earth...and it's beena good thing for the past 2 billion years...so I'm not sure you can call that misleading as such....
 * There used to be a phrase saying that too much would be bad for life, but the wording was problematic and it was removed...the discussion above about greenhouse gases on venus is about that. I don't think the current intro is in any way 'hiding' climate change, this article pretty much beats readers over the head with humans are causing global warming stuff, but possibly some sorta thing about a theoretical excess of greenhouse gases being a bad thing would be appropriate....feel free to try to come up with something appropriate, reading the previous discussion re:venus might help ya understand the problems with getting a good, sourced, phrase....92.6.233.226 (talk) 17:41, 15 January 2009 (UTC)
 * The wording that greenhouse gases are essential to maintaining the current temperature while technically correct misleads by omitting that increased GHG's is forecast to have a devastating effect on 100 million people mainly in Bangladesh and SE asia, and on many island nations. It is therefore, I believe, unacceptable. Similarly, any summary of GHG's which does not mention climate change is excising one of the most prevalent debates of the late 20th and early 21st centuries and is also therefore, I believe, an unacceptable summary. The comparative relevance of Venus having Greenhouse gases is small in my view based on the reporting of greenhouse gases in the media since the Rio Earth Summit (1992) and the degree of international government support for climate change research including the impacts of greenhouse gases since that then. dinghy (talk) 22:37, 17 January 2009 (UTC)
 * The intro is supposed to summarize the article, not related topics like climate change, global warming, repercussions of estimated continued increases of GHG levels, and so on. Especially given the large number of references that already refer to the assessment reports produced by the IPCC, the links to the articles on those subjects all through this article, and the extensive sections on anthropogenic issues in the body of the article.
 * Edited intro to relate specifically to greenhouse gases and related context, with links to pages of specific assessment report materials rather than just the table of contents of a working group report. I also added a paragraph to the section on anthropogenic greenhouse gases regarding projected impacts.  Sln3412 (talk) 21:07, 19 January 2009 (UTC)
 * To be consistent with not dealing with habitability I have removed the reference to not being inhabitable. We should either recognise the science on both sides of habitability (by all species) in the intro, or leave both to be dealt with in the body. dinghy (talk) 11:42, 20 January 2009 (UTC)
 * Rethought and reverted to your version - close enough! but maybe should be clear that GHGs are only one of a number of factors that are essential - distance fomr sun, solar energy etc Cheers!dinghy (talk) 12:12, 20 January 2009 (UTC)