Talk:Greenhouse gas/Archive 2

This is an archive of past discussions about Greenhouse gas. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page.

Archive 1

Archive 2

Archive 3

Archive 4

Archive 5

Parts Per Million

On a similar notice, the table that shows the parts per bilion of various greenhouse gasses has CO₂ listed as Parts Per Million, while all the other gasses are listed in Parts Per Billion. Seemingly intentional, this gives CO₂ the apperance of being 1000 times as present as it really is. It is also bad practice in tables generally, so it should be fixed. 81.167.52.18 (talk) 13:00, 4 February 2008 (UTC)

No, it gives the appearence of CO2 being 1000 times smaller than it is. CO2 is usually reported in ppm & methane in ppb William M. Connolley (talk) 19:26, 4 February 2008 (UTC)

Units for Concentrations and emissions

I'd really like some way of relating the emissions to the concentrations, like a worked out conversion or at least the mass of the atmosphere as 5.1e18kg from Earth's atmosphere. I realize the dynamics of the system are contentious, but for back of the envelope calculations for someone not up on this domain, mixing ppmv and megatonnes of emissions in the same discussion without providing some means of converting between the two is awkward and frustrating. Showing that CO2 at 383ppmv is 383e-6*44/29*5.15e18=2.99e15kg of CO2 and so on for the various gasses would really help. Also this non-SI mega-Tonne unit also seems like climate jargon for 10^9kg or teragram. Using global-scale non-SI units is awkward. Increasing from 0.3% to 0.383% CO2 might seem insignificant, but a 6.4e14kg increase over the last 50 years (also about 100 times China's 2006 emissions) in CO2 in our air demands explanation. (With the non-SI units, chemistry, and moles, I'm still not sure if I have my math right: These global-scale non-SI units suck.) Drf5n 03:33, 30 September 2007 (UTC)

Bear in mind that not all emissions stay in the atmos (about 50% do). And remember to distinguish emissions in tonnes of CO2 and C. But adding a conv factor could be useful William M. Connolley 09:47, 30 September 2007 (UTC)

Using the article's 6200 megatonnes (6.2Pg?) of CO2 for China seemed compatible with ppmv CO2. 50% of emissions staying in the atmos is interesting, is it the 48% in the article or something like the difference between the carbon flux lines in the 2nd graph? But for the back of the envelope calculation, it seems like the anthropogenic CO2 of a couple (4 at 50% retention) Chinas worth of industry over the last 50 years is within an order of magnitude of the 648Pg increase in CO2 we've seen. To me, this seems like clear evidence that a statement from a relative that "anthropogenic CO2 is MINOR" is wrong, easily quantifiable, and something that this article should be able to answer. The section Greenhouse_gas#Anthropogenic_greenhouse_gases seems a bit wishy-washy with the discussion of percentages of percentages, and would be a lot clearer to me with some of the actual values the percentages are based upon. Maybe I'm a fussy engineer-statistician, but I dislike Pie charts for the standard reasons and parts of this article read like one. Drf5n 03:20, 1 October 2007 (UTC)

Start with the air pressure at sea level times the area of the earth. That gives the mass of the atmosphere (they did that in the 18th century: it's not a recent realization.) The atmosphere is essentially 80% N₂ (MW 28) and 20% O₂. From that you can compute an average molecular weight and from that the volume of the atmosphere at STP. Then it's easy to compute what 1 ppm of CO₂ amounts to in mass and also to compute the mass of carbon in that 1 ppm. --Minasbeede 18:25, 30 September 2007 (UTC)

Earth's atmosphere has a lot of that and comes up with the 5.1480e18 kg of gas at about 28.97 molecular weight vs 44 for Carbon dioxide, and that's what I was trying to do above to get the 383ppmv ~ 2.99 Exagrams of CO2. Is my calculation right? or am I missing something else? Drf5n 03:20, 1 October 2007 (UTC)

Well, if I'm doing it right, the numbers I was looking for are:

R (programming language) code:

df<-data.frame(name=c('CO2','Methane','NO2','CFC11','CFC12','HCFC'),
 mw=c(44.0095,16.0425,44.0128,137.37,120.91,86.47),
 frac=c(383e-6,1745e-9,314e-9,268e-12,533e-12,69e-12),
 gwp=c(1,62,296,NA,10600,1700) )
df$Tg    <- df$frac *df$mw /28.97*5.1480e18*1000/1e12
df$equiv <- df$Tg   * df$gwp
df
     name       mw      frac   gwp           Tg       equiv
1     CO2  44.0095 3.830e-04     1 2.995265e+06 2995264.998
2 Methane  16.0425 1.745e-06    62 4.974593e+03  308424.743
3     NO2  44.0128 3.140e-07   296 2.455832e+03  726926.331
4   CFC11 137.3700 2.680e-10    NA 6.542093e+00          NA
5   CFC12 120.9100 5.330e-10 10600 1.145195e+01  121390.678
6    HCFC  86.4700 6.900e-11  1700 1.060241e+00    1802.410

Does one need to find some outside reference for these numbers, or are conversions OK editing? Drf5n 20:55, 2 October 2007 (UTC)

Human effects

Maybe I missed it, but I can't find a clear answer in the article to the question: How much would global warming decrease if all human contributions of greenhouse gasses were stopped? I see the statement that "emissions from industry, transportation and agriculture are very likely the main cause of recently observed global warming." Okay, but how much do they affect global warming? — Loadmaster 18:19, 1 October 2007 (UTC)

In the short term, global temperatures would actually continue to rise for a little while until thermal equilibrium with the current greenhouse gases is achieved. After that, it would most likely return to the historical pattern of temperature swings, but that's just my guess. Ben Hocking ^{(talk|contribs)} 18:36, 1 October 2007 (UTC)

"Uninhabitable"

"The natural component of the greenhouse effect is necessary for life to exist on Earth."

This needs a verifiable source. I don't object to it (although "for life to exist" is extreme) but it needs to be sourced. If the source doesn't support "for life to exist" then the language needs to be pared back to what the source does support. Even with a sub-freezing mean temperature it could be relatively comfortable near the equator and life could exist. --Minasbeede 12:26, 9 October 2007 (UTC)

Probably not true: sans GHE there would be far more ice, more reflected sunlight, and hence even less warmth. The calculation doesn't really work, of course, because it has to asssume an albedo that would undoubtedly change. But yes, it could do with a source William M. Connolley 16:36, 9 October 2007 (UTC)

My impression was that there was life even on a fairly young Earth when there were multiple sources of heat besides the GHGs. Ben Hocking ^{(talk|contribs)} 16:56, 9 October 2007 (UTC)

Added a ref and changed "for life to exist" to wording on habitability. Maybe viruses or prokaryotes or something like that could exist under such conditions, though that's not really my area. Raymond Arritt 16:57, 9 October 2007 (UTC)

Maybe even mammals and humans, but not as close to the poles as now. Idle speculation is worse than OR so we needn't pursue that line of thought very far. "Habitability" is a much better concept and surely more correct, and the major point remains. (Can't get to the Science Mag article. Wait, maybe I can if I log in through the university library.) --Minasbeede 17:53, 9 October 2007 (UTC)

Could, did. Seems like this is the pertinent sentence: "Planet Earth is habitable because of its location relative to the sun and because of the natural greenhouse effect of its atmosphere." --Minasbeede 18:10, 9 October 2007 (UTC)

I changed this section in my edit of the sources, to say that the 'natural component' is neccesary seemed a bit silly, as the 'natural component' could easily be either too little or too much for the Earth to be habitable, see venus. Restepc 21:42, 15 October 2007 (UTC)

Mars

Mars has an atmosphere of 95% Carbon Dioxide. Why is Mars so cold? —Preceding unsigned comment added by Whariwharangi (talk • contribs) 05:01, 25 November 2007 (UTC)

Mars is fairly warm. It reaches close to 25 C (ca. 75 F) near the mid-latitudes during a Mars day. Wedjj (talk) 07:35, 10 December 2007 (UTC)

Well, though the C02 concentration in Mars's atmosphere is higher, there's less less of it: it is a lot thinner than earth's atmosphere -- only about 59% of earth's.

More importantly, Mars is 53% further away from the sun, so (by the inverse-square law) sunlight is less than half as intense (~0.43) by the time it reaches Mars, compared with Earth. NCdave (talk) 21:05, 4 February 2008 (UTC)

POV biased

I've added (kinda, if someone could sort out the 'multiple issues' part that would be great) a POV tag to the page, as this page is meant to be about the greenhouse gasses but focuses almost entirely on human contributions to the greenhouse effect.

I'm not sure exactly what sort of bias wikipedia would normally label this as, but I'm sure anyone reading the article can see my point. Restepc (talk) 20:23, 11 March 2008 (UTC)

I took the tag out, because I disagree with it. If you think there is stuff missing, you're welcome to add it. It contains a lot about anthro GHG, because thats what people are interested in William M. Connolley (talk) 22:48, 11 March 2008 (UTC)

What people are interested in is irrelevant. If you don't want me to put the tag back up I'd appreciate you providing some reason I shouldn't Restepc (talk) 23:07, 11 March 2008 (UTC)

Make some effort to improve it. If your brilliant innovations are constantly reverted, then tag it. But if you can't be bothered to try to improve it, find something else to do William M. Connolley (talk) 23:18, 11 March 2008 (UTC)

Okay, I take that point...been planning on working on it for ages just haven't had time, see what I can do when I get a while.

On thing I'd really like help with is the graphs, I find it ludicrus that with all the graphs and charts on it, the article doesn't have one showing the sources of greenhouse gasses (well, it has several showing the manmade sources, but none showing all sources), but I have absolutely no ability to make one. Restepc (talk) 23:24, 11 March 2008 (UTC)

I've started to make relatively minor changes, if you have issue with any of them I'd appreciate talking about them here first rather than just reverting. Restepc (talk) 19:37, 12 March 2008 (UTC)

Apart from removing WV residence time, I have no problem. Asking people not to revert your changes is a waste of time, though, and unreasonable William M. Connolley (talk) 22:03, 12 March 2008 (UTC)

Oh, and the graphs. Natural sources are pretty well in balance (of course). So graphing the natural (net) sources wouldn't be interesting William M. Connolley (talk) 22:20, 12 March 2008 (UTC)

"Natural sources are pretty well in balance (of course)." I'm afraid that's highly inaccurate. The problem I had with the residence time section was the phrase 'very long time' when talking about geological timescales especially that's extremely vague....hang on I'll try another edit.Restepc (talk) 23:22, 12 March 2008 (UTC)

I'm curious, do you have a source that shows that the natural sources of GHGs are imbalanced? I'm by no means an expert on the topic, but I usually hear about how crops, trees, etc. "fix" an amount of carbon rather than actually store or give it off. My understanding is that the best a plant can do is store some carbon deep in the soil, but if the soil is disturbed (naturally or otherwise), much of that storage is lost. More carbon isn't generated through the life of a plant, though, hence why it's called a cycle. Our use of carbon isn't so much a cycle, though, since we're releasing stored carbon (fossil fuel) that would otherwise stay stored. Jason Patton (talk) 01:27, 13 March 2008 (UTC)

Look at the 'Carbon flux' graph at the top of the article. Restepc (talk) 01:29, 13 March 2008 (UTC)

Ahh, yeah, the ocean sink actually drives down the total carbon flux below our contribution. Forgot about that. So if the ocean were plotted, it would actually go negative on that graph. I still think WMC is right if we're talking vegetation, though. It wouldn't be significantly more or less than the zero throughout the carbon flux time series unless we were to look at rather short time scales. Jason Patton (talk) 08:24, 13 March 2008 (UTC)

It depends on how you regard the fluxes. Pre-industrial natural fluxes were in balance. The oceans are removing some of the anthro CO2 (about 50% of the 50%), as are others (land biota I think for the other 50% of the 50%). I still don't see what you want to put on your graphs. You could add the ocean sinks, but they aren't sources, err, they are sinks William M. Connolley (talk) 21:47, 13 March 2008 (UTC)

Jason, I had not intended to use words or phrases that are considered weasely, I'd be happy to hear what phrase you would use instead to say that this is an area that scientists aren't really sure on? Restepc (talk) 01:37, 13 March 2008 (UTC)

That's fine, I'm just being a bit nit-picky :) Really, "a very long time," "are thought to," and even "many" aren't good dictionary-style terms. What makes it tough is that some GHGs have long residence times, some are only on the order of a few years, and some are highly variable. In the case of water vapor, it's even important to specify what layer of the atmosphere is being discussed. Removing the first paragraph in that section may actually be the best solution because it's hard to hit on everything without a thorough explanation of what a gas's residence time depends on (like in the bulleted list). Jason Patton (talk) 08:36, 13 March 2008 (UTC)

The intro that said that anthro emissions were around 2%, is while correct, misleading - so i've cut it until we can get a section on the carbon cycle. I suggest a summary section of that article (really should've been here already). --Kim D. Petersen (talk) 09:59, 13 March 2008 (UTC)

The not-really-very-mysterious absence from the article of these figures was one of the 'proofs' I was going to use of its bias had I not chose the fix-it-myself option. The sentence in question is accurate, accepted by all as accurate, well sourced, highly relevant to the article, especially to that section of the article, I feel that I phrased it with perfect neutrality and I can think of no more sensible opening sentence on a section entitled "Anthropogenic greenhouse gases" than a sentence concerning how much greenhouse gas is anthropogenic.

I'm putting it back in, if you think it could be phrased in a more neutral way feel free to rephrase it and we can discuss that, if you think it should not be the opening sentence of that section (and can think of a better one, what's there now is terrible) feel free to move it to where you see fit and we can discuss that, but please do not simply remove this pertinent, factual, well sourced information. Restepc (talk) 17:10, 13 March 2008 (UTC)

Without a description of sources and sinks (ie. flux) and the Carbon cycle it is misleading. This information has its place in this article - but it has to be balanced. You response seems to indicate that you want to put a POV on the article - instead of trying to move towards NPOV. The 2% anthro emission per anno is an imbalance, and therefore accumulates in the atmosphere. The imbalance part - and the accumulation, as well as an explanation of sinks are essential to understanding the 2% figure. For instance as proposed as a summary of Carbon cycle, and possibly the Suess effect. --Kim D. Petersen (talk) 20:28, 13 March 2008 (UTC)

Kim is correct. The correct comparison is not that anthro sources are 2% of natural sources, but that anthro sources-minus-sinks are X% of natural sources-minus-sinks. That should be obvious, if what you care about is the changes in concentration (the complication of course is that the rise in CO2 due to anthro sources has increased the "natural" sinks, but that can be left aside for now). Anthro sinks are ~0. Natural sinks are ~ natural sources. So the correct comparison is between anthro sources and ~0. So the main interest in natural sources/sinks is how they are changing in response to the anthro perturbations. I'm curious: do you (a) not know this or (b) not believe it? William M. Connolley (talk) 21:47, 13 March 2008 (UTC)

It's not that I don't believe it, it's that I know for a fact that it's complete rubbish. Your argument rests upon natural sources and natural sinks being 'balanced', which is utter nonsense.

"Natural sinks are ~ natural sources."

This is absolutely untrue

Natural levels of Co2 (that seems to be the figure you guys are complaining about) varies all the time, and temperature also quite often varies naturally, they've both been changing up and down for billions of years before there were any humans: there is no mystical balance of nature that humans are upsetting.

Please leave aside the global warming debate as I would like to, for that way madness lies.

Try to look at this simple statement objectively: We have a lengthy article on greenhouse gases, that strongly gives the impression that humans are responsible for the majority of greenhouse gas emissions.

You and I know that that impression is inaccurate, wrong, misleading...whatever you want to call it, so it has to change.

You are refusing, in an article about greenhouse gases, to have accurate information on the sources of greenhouse gases, because you fear it would damage your viewpoint on a related subjects credibility. How you can possibly argue that that is not POV bias astounds me.

This article should say where greenhouse gases come from, it is information of fundamental importance to the article, to refuse to include it is absolute insanity.

I am putting it back in, and I repeat: If you want to rephrase it, do and we'll discuss that, if you want to move it, do and we'll discuss that, but removing accurate information because it does not support your viewpoint is unacceptable, and if it happens again I'll put the NPOV tag back up. Restepc (talk) 03:33, 14 March 2008 (UTC)

You have to represent the data accurately. Do natural sources emit lots of GHGs? Yep. Do they contribute to the accumulation of GHGs in the atmosphere over time? No. They also absorb roughly the same amount as they emit. That's why it's a cycle. However, this cycle is confined to natural sources since anthropogenic sources only emit GHGs, not absorb them. That is the main cause of the accumulation (not emission, not adsorption) of GHGs in the atmosphere over the last 150 years. To represent the scale of anthropogenic emissions next to other sources without this underlying background of a natural cycle that absorbs what is emitted is not NPOV. Jason Patton (talk) 06:18, 14 March 2008 (UTC)

As I have already said, there is no magical balance of nature, if Yellowstone were to suddenly go off some other natural phenomenon would not suddenly leap up to absorb the emissions. There is no higher power making sure the natural sources and natural sinks balance: all the available data shows that they don't and haven't balanced. Sometimes the available sinks are greater than the sources, and the level of CO2 falls, sometimes the sources are greater than available sinks and the amount of CO2 rises. Both of these situations have existed without human sources within the past 50,000 years. Currently sources are greater than sinks by a very small amount, and CO2 is slowly increasing. If you add up all the human sources, you find that it comes to 2% of total source emissions, and that if humans weren't emitting this 2% then CO2 levels would probably not be rising.

Therefore you can say that humanity is very probably causing CO2 to rise, and further that this rise could be a very bad thing and cause all sorts of catastrophes. None of which is any argument whatsoever for this article giving the impression (as it currently does) that humans are responsible for considerably more than 2% of emissions.

The article currently gives a grossly inaccurate impression of the facts, therefore I dispute its neutrality.

I'll discuss the format I think the article should take (a subject on which I suspect Kim and I may have common ground) some other time, but for now I'll mention a few things from the wikipedia guides on how to deal with POV disputes.

"In general, you should not remove the NPOV dispute tag merely because you personally feel the article complies with NPOV."

"While each fact mentioned in the article might be presented fairly, the very selection (and omission) of facts can make an article biased."

"When you find a passage in an article biased or inaccurate, improve it if you can. If that is not possible, and you disagree completely with a point of view expressed in an article, think twice before simply deleting it. Rather, balance it with your side of the story."

Restepc (talk) 18:52, 14 March 2008 (UTC)

I'd go through and reword the article to make clear the difference between emissions and accumulations and add how different natural equilibrium levels have been reached in the past, but I will be out of town for the next week. Please feel free to go ahead and make these sorts of clarifications; the article needs them. I still stand by that flat out stating that human emissions are 2% of total emissions without any context is not NPOV because the reader will have no background in which to interpret that data.

"While each fact mentioned in the article might be presented fairly, the very selection (and omission) of facts can make an article biased." Jason Patton (talk) 20:41, 14 March 2008 (UTC)

Oh dear. I strongly suspect that talking here is not going to do any good, I suppose its worth trying. In pre-industrial times, natural sources ~balanced sinks. YOu can tell that, because GHG's were stable at ~280 ppmv for ~10,000 years. Since then, human emissions have caused the level of CO2 to rise to ~380. You do accept that humans are responsible for this increase, don't you? If you don't, you're lost, and we may as well give up William M. Connolley (talk) 21:05, 14 March 2008 (UTC)

If you read what I wrote you may have noticed the sentence "If you add up all the human sources, you find that it comes to 2% of total source emissions, and that if humans weren't emitting this 2% then CO2 levels would probably not be rising."

Please do not remove the POV tag again, it even says on the tag itself 'please do not remove this tag'. Restepc (talk) 21:15, 14 March 2008 (UTC)

I've removed the tag. Please do not use tagging as a way to try to force your POV. That is not the way that the tag should be used, and especially not when there is an active discussion on the subject. Now you seem to be the odd man out for your specific way of wanting to show things, but i have as yet not seen anyone who doesn't agree that the information should be presented in the article - it just has to be presented in a balanced way, so that it doesn't mislead. Try reading the quote on POV again that both you and Jason focused on. --Kim D. Petersen (talk) 21:32, 14 March 2008 (UTC)

"probably" isn't good enough. Have a look at, e.g., http://www.globalwarmingart.com/wiki/Image:Carbon_Dioxide_400kyr_Rev_png (its on wiki somewhere too). The sentence you quote shows how fundamentally you're confused. What matters for changes in GHG levels is not sources, but sources-minus-sinks William M. Connolley (talk) 21:34, 14 March 2008 (UTC)

~~I'm putting the tag back up,~~ as I said earlier when I get chance to explain how I think this article should look you may find you agree with me.

Please read http://en.wikipedia.org/wiki/Wikipedia:NPOV_dispute

You should not remove a POV tag simply because you disagree with it. The only reason you should remove the tag is if there is not a dispute about the neutrality of the page, and as there clearly is as I am disputing it, the tag should remain. Restepc (talk) 21:41, 14 March 2008 (UTC)

Tags are text. Don't teach your grandmother to suck eggs. You need to understand the difference between sources and sources-minus-sinks William M. Connolley (talk) 21:53, 14 March 2008 (UTC)

That difference is irrelevant to the POV tag, the POV tag is to show that there is a dispute over the neutrality of an article.

Do you agree that there is a dispute over the neutrality of the article?

If yes, please put the tag back, if no please note that I am disputing the neutrality of the article. Restepc (talk) 21:58, 14 March 2008 (UTC)

If it were possible to dispute neutrality based on the opinion of one disgruntled editor not being able to edit the page the way they wanted, many controversial pages would be constantly tagged - global warming and evolution most obviously. Now, back to sources-minus-sinks William M. Connolley (talk) 22:04, 14 March 2008 (UTC)

Except that I clearly stated that I viewed the page as POV biased before the disagreement about this particular edit, and that it is far more than this singular edit which makes me think it is POV biased. Restepc (talk) 22:09, 14 March 2008 (UTC)

Yes yes, you've made it clear you don't like the page. But you've failed to substantiate your dislike with any science, so we don't think your tag is justified William M. Connolley (talk) 22:34, 14 March 2008 (UTC)

One of the reasons I think this article is not neutral is because it gives undue weight to human sources over natural. I originally looked up this article ages and ages ago to find out what proportion of ghg emissions was from human sources and what proportion is from natural sources, this information being absent is one example of the bias of the page. I feel that a layman reading this article would come away with the impression that human sources accounted for considerably more ghg emissions than they actually do.

Basically I object to the fact that virtually the entire article talks about human emissions and natural sources are not mentioned. Restepc (talk) 22:56, 14 March 2008 (UTC)

Inasmuch as it is indisputable that the neutrality of this article is disputed, I have restored the neutrality-disputed tag. William & Kim, the justification of the tag is the fact that some users dispute the neutrality of the article. You needn't agree with them to admit that the neutrality is, indeed, disputed. Please leave the tag alone until the dispute is resolved. NCdave (talk) 05:36, 15 March 2008 (UTC)

And i've removed it again. I suggest that you read a bit more than part of a section, since your reinsertion comment ("The neutrality of this article is indisputably disputed, so please do not remove the tag until the dispute is settled."), and this one, indicates that you haven't understood WP:NPOV. Under your understanding, all controversial articles (and many more) would constantly be marked POV, since there would always be a dispute.

Now if you have some input to the discussion of this particular case, then please make it. Because so far, there seems to be a consensus that Restpc's edits is pushing the article towards POV and not away from POV. --Kim D. Petersen (talk) 11:00, 15 March 2008 (UTC)

Two friends agreeing with each other that an article they have written is neutral does not make a consensus. Of all the ways I imagined this going I never in a million years thought this would happen, this is really really really stupid. Can you not simply admit that I am disputing the neutrality of this article so maybe we can work on improving it?

Restepc (talk) 17:48, 15 March 2008 (UTC)

Kim & Wm, please stop removing the neutrality-disputed tag, since you know that the neutrality of this article is disputed. Please read WP:NPOV. According to Wikipedia policy, the tag should be removed after the dispute is resolved. NCdave (talk) 21:40, 15 March 2008 (UTC)

The tag is not supposed to be used in this way, please read 2 first paragraphs in Wikipedia:NPOV dispute. I'll quote from it: Simply being of the opinion that a page is not neutral is not sufficient to justify the addition of the tag. Tags should be added as a last resort..

It is not to be used as a marker of content disputes (which is currently the case). --Kim D. Petersen (talk) 00:05, 16 March 2008 (UTC)

Also, please see my comment under Why do almost all the graphs lie? NCdave (talk) 22:22, 15 March 2008 (UTC)

Airborne fraction

I'm rather puzzled by what is supposed to be wrong with the airborne fraction concept [1], other than "does not compute" William M. Connolley (talk) 22:30, 14 March 2008 (UTC)

I suspect plantsurfer does not find that section particularly clear.

Perhaps simply shortening it to 'A related concept is airborne fraction, being the amount of an emitted gas which remains in the atmosphere' would be a bit clearer, but to be honest I'm not sure about it at all, the concept of airborne fraction isn't amazingly well known (doesn't have its own wiki page for example), and the % that was given on the article (50%) is not universally accepted anyway. Maybe it should just be left out. Restepc (talk) 22:43, 14 March 2008 (UTC)

The definition of airborne fraction was obscure, and needs to be clarified. In particular, it was meaningless without a statement of the time after emission. HS Keshgi (2004) "Evasion of CO2 injected into the ocean in the context of CO2 stabilization." Energy 29, 1479-1486, defines it as follows: "The airborne fraction is defined as the fraction of the emission that adds to the atmospheric concentration. The airborne fraction for atmospheric release is 1 at the time of emission and declines as CO2 is dissolved in ocean-surface waters, mixed into the deep ocean and partially neutralized by dissolution of CaCO3 sediments. The airborne fraction for deep-ocean injection begins at 0 and does not rise significantly for at least 100 years." It is clear from this, and one of the key reasons for my revert, that a statement of airborne fraction that is not explicit about the time since emission is meaningless. A better-understood concept would be half-life, perhaps, but I don't have a fundamental objection to the use of the airborne fraction concept, provided it is properly defined. A citation would also help.Plantsurfer (talk) 23:22, 14 March 2008 (UTC)

Jolly good, then lets clarify it. No, its not meaningless without a timescale, and is commonly used without one; e.g. [2] William M. Connolley (talk) 18:18, 15 March 2008 (UTC)

Excellent citeable ref., good work. But it really is not true that the definition is independent of time. There is a time-frame of a year. The definition they use amounts to the fraction of the annual emission that remains in the atmosphere, i.e. that is not removed by sinks in that year.Plantsurfer (talk) 19:29, 15 March 2008 (UTC)

Perhaps I am mistaken, but I would suggest that the pdf you provided does in fact have a timescale. It appears to be defining the annual AF of human emissions as the % amount of the increase in CO2 in the atmosphere over one year is of human emissions over that year.

While this seems to me to be an slightly incorrect usage of the term airborne fraction (as in reality the increase in atmospheric CO2 wouldn't be entirely man made particles but would be roughly 98% natural particles (that had had 'their' part of a sink usurped by human CO2)), it is relatively clear if you read it that they are using a timescale of one year (well, sort of, like I say I'm not confident they're using the concept correctly).

I suggest that if AF is to be included in the article, we use the definition/source plantsurfer used to explain it. HS Keshgi (2004) "Evasion of CO2 injected into the ocean in the context of CO2 stabilization." Energy 29, 1479-1486, defines it as follows: "The airborne fraction is defined as the fraction of the emission that adds to the atmospheric concentration. The airborne fraction for atmospheric release is 1 at the time of emission and declines as CO2 is dissolved in ocean-surface waters, mixed into the deep ocean and partially neutralized by dissolution of CaCO3 sediments. The airborne fraction for deep-ocean injection begins at 0 and does not rise significantly for at least 100 years."

Although I would suggest that we change 1 to 100% and 0 to 0% for the benefit of the 'average man on the street', if this would be an acceptable interpretation of the source. Restepc (talk) 19:12, 15 March 2008 (UTC)

Restepc, you seem to be eager to get around the fact (and sorry it is), that human emissions, is the cause for the ~35% increase in atmospheric CO2 (and quite abit more for the other GHG's). And that is POV - and has no place here.

The reason that the sources are talking only about anthropogenic emissions, is that the nett emissions from nature is negative (sources-sinks). That is the scientific assessment. Stating anything other is undue weight to a fringe belief, that isn't reflected in the scientific literature. Sorry. --Kim D. Petersen (talk) 21:15, 15 March 2008 (UTC)

So, let me get this right, up to the Industrial revolution CO2 emissions from nature were eliminated by the sinks? That implies there was no detectable pre-industrial CO2 concentration? Clearly false, since we are here discussing it today.Plantsurfer (talk) 21:32, 15 March 2008 (UTC)

My statements imply no such thing - to imply that i should have claimed that natural sources and sinks couldn't vary. Before preindustrial time (on smaller than geological timescales), sources where roughly equal to sinks. Variations in GHG's (pre-ind) where caused by either T inc/dec, or by volcanic eruptions. The preindustrial equilibrium was around ~280±20ppm. for interglacials, and 180±20ppm for glacial periods. --Kim D. Petersen (talk) 21:45, 15 March 2008 (UTC)

Kim I am well aware that all the evidence strongly suggests that human emissions are causing CO2 levels to rise, I have said as much several times, and have never either said anything else or suggested including anything else in the article. Please do not put words into my mouth and can we actually talk about improving this article. Restepc (talk) 21:33, 15 March 2008 (UTC)

Natural Greenhouse gases

A section with this title is required in the main article to provide balance and context, and to make it clear that greenhouse gases are not merely anthropogenic waste, but a natural phenomoenon as well. The biosphere is completely dependent on the existence of greenhouse gases, and has been influencing their concentrations constantly for more than two billion years. The article at present contains no clear statements of the relative amounts of anthropogenic and natural emissions of greenhouse gas emissions and their sinks. There is an excellent balance sheet on the Methane page which could be referenced, but the Carbon dioxide page lacks a clear statement of sources and sinks. I suggest we should try to find this information and incorporate it. There is also no summary of the relative magnitude of greenhouse gas concentrations today compared with those of the past, when both methane and CO2 concentrations were sometimes very much higher than they are today. This information is required for context, and for comparison with the magnitudes of the anthropogenic emissions we are currently producing.Plantsurfer (talk) 11:01, 15 March 2008 (UTC)

There is indirect evidence of CO2 having been higher in the past, though not recently: Image:Carbon Dioxide 400kyr.png; Image:Phanerozoic Carbon Dioxide.png. I'm not aware of evidence for methane having been higher, though William M. Connolley (talk) 14:30, 15 March 2008 (UTC)

Suggest you read Methane clathrate, Paleocene-Eocene Thermal Maximum and Permian-Triassic extinction event and references therein, and then take a look at the evidence for atmospheric composition during the Precambrian.Plantsurfer (talk) 15:23, 15 March 2008 (UTC)

Theres quite a bit there. Perhaps you could point out the bit where it says methane levels were...? William M. Connolley (talk) 15:43, 15 March 2008 (UTC)

As far as I am aware, there is no measurement technique for determining atmospheric methane beyond the availability of ice cores. Dragons flight (talk) 16:54, 15 March 2008 (UTC)

Plantsurfer may I request a comment from you on the current POV tag debate? Restepc (talk) 17:52, 15 March 2008 (UTC)

As you can see, I tend to agree with you that the article lacks an adequate statement of the importance of natural emissions and their historical record. But I don't like the POV template, and you can see from the reaction it has provoked that others dislike it as well. The way forward is to contribute good, constructive, high-quality edits to the article in an atmosphere of good faith and consensus.Plantsurfer (talk) 19:43, 15 March 2008 (UTC)

Thankyou for your input, however I will point out that that is quite plainly not what has been agreed as wikipedia policy Restepc (talk) 20:22, 15 March 2008 (UTC)

I've added "present CO2 levels are 380 ppmv, approximately 100 ppmv higher than they were in pre-industrial times" - does that help? William M. Connolley (talk) 22:31, 15 March 2008 (UTC)

Unless you have a very strange definition of the word help, then no. Restepc (talk) 22:50, 15 March 2008 (UTC)

But I thought you wanted to see what proportion of the current GHG levels were natural and anthropogenic? That tells you: CO2 is currently 100/380 anthro. Methane, of course, would be more William M. Connolley (talk) 23:14, 15 March 2008 (UTC)

Canvassing ahoy

[3]. MastCell ^Talk 21:50, 15 March 2008 (UTC)

I was active here long before that. NCdave (talk) 22:28, 15 March 2008 (UTC)

Following the suggestions on the dispute resolution page I asked three people for their input, one person who has been previously active on this page(Ncdave), one person who has come along as this dispute is in progress (plantsurfer) and one other person who has no history (that I am aware) of any edits in global warming or related matters who has yet to respond.

I have never exchanged any communications with any of these people before this dispute, and was contacting them following the advice I found on the dispute resolution page. If you have any objection with this method I suggest you take it up with those people who wrote the dispute resolution page, as I was under the impression that this would be the appropriate way to go forward.

Restepc (talk) 22:41, 15 March 2008 (UTC)

You hit 3 reverts and then went to a user who agrees with your position and said, "Boy, the article needs a tag but I've hit my revert limit." That's actually not part of the dispute resolution pathway. Yes, nearly 24 hours later you messaged a second editor ([4]), but requesting others to pick up the banner for you once you hit 3 reverts is widely, and correctly, seen as gaming the system. MastCell ^Talk 04:52, 16 March 2008 (UTC)

I apologise if I have in any way broken any rules, I was acting in what I considered was the correct way at the time.

After consulting the wikipedia page on dispute resolution, I decided to get another opinion and scrolled up on this talk page until I saw a user who wasn't already involved in discussion, I specifically said that I was not asking him to re-add the tag, I was just frustrated beyond belief at the situation which so blatantly went against wikipedia policy on the POV tag as I understand it and the fact that I was the one being threatened with breaking the rules in this situation.

I had no way of knowing NCDave would agree with me, I have never ever had any sort of contact with him before leaving that note on his talk page, I did however assume that he would agree with the basic fact that the POV tag should not be removed from a page until the POV dispute has been resolved, because unless my reading comprehension is at a considerably lower level than I have been lead to believe that is quite clearly wikipedia consensus on the matter.

When NCDave did agree with me and that was still not enough to stop them removing the tag I asked plantsurfer, who also agrees that the page is unbalanced but did not put the tag back up because he does not agree with the policy of tagging articles, this was still not enough so I asked Scuro, who I also have never had any sort of communication with and who I believe has never contributed to any environmental articles and can safely be considered a complete outsider.

As he has not yet responded I would be very grateful if you would give your impartial opinion on their actions in repeatedly removing the tag despite the fact that 3 separate users have now said that the page is not balanced, and despite the fact that the wikipedia page on POV tags says

"In any NPOV dispute, there will be some people who think the article complies with NPOV, and some people who disagree. In general, you should not remove the NPOV dispute tag merely because you personally feel the article complies with NPOV. Rather, the tag should be removed only when there is a consensus among the editors that the NPOV disputes have indeed been resolved.

Sometimes people have edit wars over the NPOV dispute tag, or have an extended debate about whether there is a NPOV dispute or not. In general, if you find yourself having an ongoing dispute about whether a dispute exists, there's a good chance one does, and you should therefore leave the NPOV tag up until there is a consensus that it should be removed." ?

Restepc (talk) 06:10, 16 March 2008 (UTC)

The role of water vapor

This section currently says:

...an increase in atmospheric temperature caused by the greenhouse effect due to anthropogenic gases will in turn lead to an increase in the water vapor content of the troposphere, with approximately constant relative humidity. The increased water vapor in turn leads to an increase in the greenhouse effect and thus a further increase in temperature; the increase in temperature leads to still further increase in atmospheric water vapor; and the feedback cycle continues until equilibrium is reached."

That description is obviously wrong. The positive-feedback cycle described cannot reach equilibrium. To reach equilibrium, negative feedback is necessary. (BTW, I have a degree in Systems Science.) NCdave (talk) 22:03, 15 March 2008 (UTC)

Errr... this may just be a terminology problem. Its like this, but with simplified numbers: T goes up 1 oC, increasing WV by X. This in turn increases T by 0.5 oC. An increase of 0.5 oC increases WV by X/2. This increases T by 0.25. Which increases WV by X/4. I'm sure you can see that this converges. You're welcome to find some negative feedback in there if you like. In the real world, of course, it all happens together rather than in discrete steps William M. Connolley (talk) 22:28, 15 March 2008 (UTC)

Okay, I see. Yes, the description needs to be tweaked. Are there references for actual numbers? NCdave (talk) 22:41, 15 March 2008 (UTC)

It'll be in IPCC; most things are William M. Connolley (talk) 22:49, 15 March 2008 (UTC)

Obviously, net negative feedback components exceed the positive. Otherwise, the temperature would go up without limit.

The most fundamental negative feedback component is simply that radiated heat goes up with temperature.

Water is complex. On one hand, as temperature goes up increased H2O vapor contributes to the greenhouse effect by blocking the escape of some IR radiation (positive feedback). Likewise, decreased snow cover decreases surface albedo and increases the absorption of solar radiation (also positive). But, on the other hand, as temperature goes up so does cloud cover, which increases albedo and reduces absorption of solar radiation during daytime (negative feedback) but decreases the escape of radiation at night (smaller positive feedback). What's more, all these effects very greatly with temperature, and thus with latitude, altitude, and season, making quantification even more challenging.

It may well be that, at current temperatures, the net contribution of water is a positive feedback component, but to state this we need numbers and reliable sources. If we can find them, it should be possible to say that something along the lines of, "most experts believe that the net effect of water evaporization is to magnify temperature shifts by between 10% and 50%," or something like that (I just made up the numbers). If you can find such numbers, please share them.

The current wording is alarmist and misleading, gives no clue to the actual magnitude of the net effect, and (as far as I can see) is unsupported by the cited sources. NCdave (talk) 07:04, 19 March 2008 (UTC)

As temperature goes up so does cloud cover. Do you have a source for that? Raymond Arritt (talk) 19:28, 19 March 2008 (UTC)

Sure, see below. NCdave (talk) 15:23, 24 March 2008 (UTC)

Dave is right. The sentence " ... feedback cycle continues until equilibrium is reached" makes no sense. William is bluffing about the IPCC. Where is this explained in the IPCC William? Also it's worth noting that the 36% - 66% figure comes from an unreliable blog that William wrote for until recently. Is there a more reliable source? Paul Matthews (talk) 18:39, 19 March 2008 (UTC)

Yep - of course he is bluffing... AR4 chapter 3 subsection 3.4.2 is not about the water vapour feedback - and neither does chapter 8 subsection 8.6.3 mention anything about how its modelled either. Its all an illusion, and WMC is hallucinating ;-) --Kim D. Petersen (talk) 19:11, 19 March 2008 (UTC)

RC is correctly accepted as an RS by wiki. Follow the link and you'll find the numbers from R, 1978, if you prefer those; they are much the same. Or follow your wacko septic friends to produce nonsense numbers, if you must, just don't put them in wiki (did someone say clearlight?) William M. Connolley (talk) 23:56, 19 March 2008 (UTC)

Will, as you have recently warned me about civil behaviour you may want to reconsider some of the things you say. I imagine that if you ever did want to make a complaint about someone your case would be considerably weakened by your own insult throwing.

Paul, as I understand it the blog in question is (albeit somewhat controversially) accepted by wikipedia as a source and can be used..... although personally I'd suggest using alternatives where possible to avoid such accusations. Restepc (talk) 18:57, 20 March 2008 (UTC)

Q: Raymond asked:

As temperature goes up so does cloud cover. Do you have a source for that?

A: I've read it in many places, Raymond. Here's one that Google turned up:

Temperature—Cloud Cover—Radiation Feedbacks

Feedbacks between temperature, cloud cover and radiation are potentially important agents of climate change. However, they are not well understood and research in this area is active.

It is thought that if climate warms, evaporation will also increase, in turn increasing cloud cover. Because clouds have high albedo, more cloud cover will increase the earth's albedo and reduce the amount of solar radiation absorbed at the surface. Clouds should therefore inhibit further rises in temperature. This temperature—cloud cover—radiation feedback is negative as the initial temperature change is dampened.

However, cloud cover also acts as a blanket to inhibit loss of longwave radiation from the earth's atmosphere. By this process, an increase in temperature leading to an increase in cloud cover could lead to a further increase in temperature – a positive feedback.

Knowing which process dominates is a complex issue. Cloud type plays a strong role, as do cloud water content and particle size. Another factor is whether the cloud albedo is higher or lower than that of the surface. Research indicates that the effect of this feedback in the Arctic may be different than in other latitudes. Except in summer, arctic clouds seem to have a warming effect. This is because the blanket effect of clouds tends to dominate over reductions in shortwave radiation to the surface caused by the high cloud albedo.[5]

Does that help? NCdave (talk) 15:23, 24 March 2008 (UTC)

Not really. For one, it isn't clear whether he's talking specifically about the arctic (where such a feedback is more plausible) or the global atmosphere (where it is less plausible). For two, he doesn't cite a reference for the statement. Raymond Arritt (talk) 15:39, 24 March 2008 (UTC)

It seems clear enough to me. The topic of the article is arctic warming. It says, "Research indicates that the effect of this feedback in the Arctic may be different than in other latitudes. Except in summer, arctic clouds seem to have a warming effect." Different from warming means cooling.

In the Arctic winter, there is little incident solar radiation, so the higher albedo caused by increased cloud cover has little effect on it. In general, increased could cover decreases daytime temperatures, and thereby (to a lesser extent) decreases overall average temperatures, but in the Arctic winter there is no daytime to be affected.

The source is given as NSIDC at U. Colorado[6].

A google search finds lots of references to this effect. Here's another.[7] NCdave (talk) 16:24, 24 March 2008 and 15:55, 25 March 2008 (UTC)

anthropogenic components of various GHGs

Kim, you deleted this from the article:

"Approximately 2% of Carbon Dioxide emissions, one third of Nitrous Oxide, and 60% of Methane are from human activity.<ref>http://www.ec.gc.ca/pdb/ghg/about/gases_e.cfm</ref>"

Your edit summary was:

"rv misleading, to the point of pushing a POV. I thought this was about NPOV?"

I don't think your deletion or your harsh edit summary was justified.

I do think that there is a minor problem with the sentence that you deleted. A careful reading of the Canadian government reference that you deleted shows that the 2% figure for CO2 is the percentage of emissions which are anthropogenic in origin, but the 60% figure for Methane and the "one third" figure for N2O are for atmospheric concentration levels, rather than emission rates. The sentence you deleted is not actually wrong, but it could easily be misread to mean that all three figures were about emission rates. So, some clarification would be helpful. But simply blanking the whole thing, including the reference, is not the right solution. NCdave (talk) 23:06, 15 March 2008 (UTC)

This comes round fairly frequently, indeed its all above now. The point of interest is source-sink, not just source. You could read the discussion there, or I suppose I could paste it in again here... William M. Connolley (talk) 23:16, 15 March 2008 (UTC)

"There" = where? NCdave (talk) 23:27, 15 March 2008 (UTC)

See the discussion under Talk:Greenhouse gas#POV biased. Where the revert reasons where specifically addressed. --Kim D. Petersen (talk) 23:44, 15 March 2008 (UTC)

I added a brief discussion of natural vs anthro sources and sinks for CO2. Maybe I'll do CH4 and N2O later. Raymond Arritt (talk) 00:54, 16 March 2008 (UTC)

Thank-you Raymond, a vast improvement. Restepc (talk) 01:34, 16 March 2008 (UTC)

Where are we now?

Where are we now? It would seem that some comparison of natural vs anthro GHGs would be desirable. How about a section; "natural and anthro GHGs", mostly consisting of a table like IPCC list of greenhouse gases, only up to date, to show the proportion of the various gases that is natural/anthro? William M. Connolley (talk) 19:47, 17 March 2008 (UTC)

Sounds good. You're the specialist, so best if you start it.Plantsurfer (talk) 22:21, 17 March 2008 (UTC)

I'm not so sure....a section contrasting natural and anthro GHGs could be useful, but currently we already have a section focusing entirely on anthro, perhaps making that section into the proposed section would be an idea....

The problem is that way I see it, if we keep a seperate section on anthro GHGs then we're going to need a seperate section on natural GHGs, which I feel is just setting the article up to become a further extension of the global warming controversy.

A possible alternative approach that occurs to me would be to use timescales, one section about GHGs over the lifespan of the earth (which I think would be appropriate no matter what), one about the last few hundred thousand years showing the iceage pattern, one about the last 10,000 years and one about the last....400 (or 500, 350..whatever).

The last 10k years section would essentially be an explanation of the current and recent past natural GHG levels, sources, sinks etc, with the most recent 400 showing the effect human behaviour is having on that system and containing the most up to date data. In other words the last two sections (10k and 400) would perform the role of the natural vs anthro GHG section being suggested.

Your thoughts? Restepc (talk) 10:59, 18 March 2008 (UTC)

I would be interested to see what some of your proposed new sections look like, but I suggest for the time being that you add in the new material without upsetting the existing structure. Also, please make these unique contributions, and don't simply copy in material already on other pages.Plantsurfer (talk) 11:17, 18 March 2008 (UTC)

Seeing what they look like probably isn't going to be a great advert if I'm going to be the one making them, they'll certainly be completely lacking in graphs, but I'll see what I can do...probably go for the 'over earths history' section as something completely uncontroversial....

~~Now that I think about it, when I've worked on other pages I've used the talk page to draft works in progress, will probably do the same here.~~ Restepc (talk) 11:32, 18 March 2008 (UTC)

After observing more closely the editing of this article, and reasearching past conduct of those editors in control of it, I've decided that any attempt to introduce neutrality would be extremely unlikely to succeed, and would if anything lead me to being driven off wikipedia. Therefore I'm abandoning this article until a time when I feel the powers that be here are more impartial, and will be spending my time working on other areas in need Restepc (talk) 06:27, 11 April 2008 (UTC)

That's ridiculous, and a great shame. It is a pity you didn't put as much energy into editing the article as you did into editing the talk page. How will anyone know what the balancing POV you keep talking about is unless you present it in the article. Plantsurfer (talk) 08:05, 11 April 2008 (UTC)

Anthro gases are doing more exciting things; there is more to say about them. In comparison, the natural ones haven't done a lot in 10 kyr William M. Connolley (talk) 22:40, 18 March 2008 (UTC)

Indeed, but I think the article should say what the current (or currentish) natural situation is, because the focus purely on human GHGs makes the article non-neutral....to clarify, the 10k section wouldn't be about natural variations, as there haven't really been any (or not that I know of, I'm mainly thinking about CO2 atm), but would give an explanation of the pre-industrial situation, with the natural sources and sinks etc. I think approaching the section as a 'last 10k years' section rather than a 'natural GHGs' section makes sense on two levels, firstly it would fit in with the sections on GHGs over the earths lifetime and over the past few hundred thousand years, and secondly if we set it up as a 'natural GHGs section' and have the last section being set up as a human GHGs section I think it would be a situation likely to atract the global warming debate to this article, which I think is something to be avoided. Restepc (talk) 10:33, 19 March 2008 (UTC)

Removal from the Atmosphere, and all that gas

Having tried to fix Airborne fraction (I hope) my eye is unavoidably drawn to the following, a little way below: "Two scales can be used to describe the effect of different gases in the atmosphere. The first, the atmospheric lifetime, describes how long it takes to restore the system to equilibrium following a small increase in the concentration of the gas in the atmosphere. Individual molecules may interchange with other reservoirs such as soil, the oceans, and biological systems, but the mean lifetime refers to the decaying away of the excess. It is sometimes erroneously claimed that the atmospheric lifetime of CO2 is only a few years because that is the average time for any CO2 molecule to stay in the atmosphere before being removed by mixing into the ocean, uptake by photosynthesis, or other processes. 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."

Are we happy with that? Does this concept of atmospheric lifetime have any significance that Airborne fraction lacks, apart from the undoubted poetry of the meanderings of individual molecules? If so, please explain.Plantsurfer (talk) 17:18, 18 March 2008 (UTC)

AF and lifetime are very different. The distinction between the molecules and the concentration is also important William M. Connolley (talk) 22:38, 18 March 2008 (UTC)

Atmospheric lifetime I think should stay in the article, but I'd like a bit of clarification of it, for example what is meant by equilibrium...and the CO2 argument is a bit strange as well, is the atmospheric lifetime of a GHG how long it lasts in the atmosphere (which is the definition which would make sense to me), or is atmospheric lifetime how long the distortion caused by a specific emission unusual to longer term trends lasts?

Possibly (and this is just me making a guess) Atmospheric lifetime of CO2 is just a few years, and the unclear sentence is a result of someone trying to explain that even though the specific molecules of an unusual CO2 emission only last a few years, the effect that unusual emission has on atmospheric concentrations lasts longer because it has kinda a mexican wave effect on the absorbtion of 'normal' emissions... Restepc (talk) 10:25, 19 March 2008 (UTC)

Atmospheric lifetime is refering to the timescale required for the atmosphere to recover following a perturbation, i.e. your second concept. In the case of CO2, the residence time of individual molecules in the atmosphere is much shorter than the atmospheric lifetime of the perturbation. Dragons flight (talk) 16:35, 19 March 2008 (UTC)

Thanks, that's much clearer....now to figure out how to say that in the article itself....'kinda a mexican wave effect' probably isn't very scientific. Restepc (talk) 23:51, 19 March 2008 (UTC)

Can I put the POV tag back up yet?

Ya know, now that the two sections explaining how humans are causing GHG levels to rise above natural levels and the section explaining that human released GHGs are responsible for rises in the levels of water vapour and the section featuring useful technical stuff but nevertheless for some completely unknown reason still illustrated with diagrams of how humans are releasing GHGs and causing levels to rise above natural levels.....have been helpfully balanced out by the addition of yet a third section explaining how humans are causing GHG levels to rise above natural levels....

Restepc (talk) 03:27, 21 March 2008 (UTC)

I seriously think that would be unhelpful, and urge you not to do it. We are gradually making progress. What is this POV tag going to achieve except to stand as a nagging criticism of the contributions made to date? William has started a natural emissions section. What is needed now is contributions to it. Why don't you contribute to it?Plantsurfer (talk) 09:04, 21 March 2008 (UTC)

I believe the POV tag is supposed to serve as a warning that the page is unbalanced, or there is dispute about whether or not it's balanced, going by youroutlook it shouldn't be used ever...which is perhaps your opinion I suppose which I can understand, although I strongly disagree with it. When I get the time I intend to begin to create an alternative set of sections to the current sections 4 and 5, and now 3 as well. I'll make them on the talk page and swap them only when it becomes totally clear that they are preferable, because it is clear that any piecemeal edits I make will be reverted.Restepc (talk) 14:21, 21 March 2008 (UTC)

I'm not clear what you want (other than something like an unqualified "natural fluxes of co2 are much larger than human fluxes", which you're not going to get). The new section compares natural and anthro fluxes, just as you said you wanted. Maybe some material from other sections could be moved into it. Try, cautiously William M. Connolley (talk) 09:59, 21 March 2008 (UTC)

I am finding it seriously difficult to assume good faith on your part Will, if you can't understand what I want after what I just said then I'd best not finish this sentence Restepc (talk) 14:13, 21 March 2008 (UTC)

Is it your view that human activity is not causing GHG concentrations to rise above their natural values, and therefore the article is POV? If you can cite some papers backing up this assertion, let's discuss. Raymond Arritt (talk) 15:31, 21 March 2008 (UTC)

Well, GHGs have been 'naturally' much higher than they are now, but I know that's not what you're talking about, and no what you're thinking of is not my view. Restepc —Preceding unsigned comment added by 92.0.53.66 (talk) 16:07, 21 March 2008 (UTC)

The {{POV}} tag does need to be restored to the article, in my opinion. Here's one of the reasons. NCdave (talk) 15:29, 24 March 2008 (UTC)

That's a very long discussion that ranges over several different topics. Can you be more specific? Raymond Arritt (talk) 15:40, 24 March 2008 (UTC)

Sure. The problem is that the "role of water vapor" section's "...current wording is alarmist and misleading, gives no clue to the actual magnitude of the net effect, and (as far as I can see) is unsupported by the cited sources.." The current (bad) wording of the article says:

"water vapor acts as a positive feedback to the forcing provided by human-released greenhouse gases,"

That is not clearly true, and it certainly is not well-supported by current research. Water vapor actually has both positive and negative feedback effects, and whether the net effect is positive or negative is not known:

"Currently it is not known whether the total effect of these changes [water vapor / cloud feedback effects] will be a negative or positive feedback" ... "Depending on whether and how cloud cover changes, the cloud feedback could almost halve or almost double the warming."[8]

That problem, alone, IMO, is sufficient to justify both neutrality and accuracy warnings.

Another problem justifying the {{POV}} tag is the graphs with illegibly tiny Y-axis labels, that do not start at zero.[9][10] NCdave (talk) 16:26, 25 March 2008 (UTC)

I've restored the neutrality-disputed ({{POV}}) tag. It really needs an accuracy warning, too. NCdave (talk) 16:31, 25 March 2008 (UTC)

(ec) OK, I see. We need better referencing. There's no doubt whatsoever that the water vapor feedback is positive both in terms of observations and basic principles. I'll add some references to the observational studies, which I think most people will consider more convincing than the modeling ones. The bit about the axis labels seems like an awfully trivial point, but speaking as an old guy who wears reading glasses I agree the graph should be fixed. Raymond Arritt (talk) 16:35, 25 March 2008 (UTC)

Actually, there is plenty of doubt that water vapor/cloud feedback is positive. I've given two reliable sources for that fact, do you need more?

There are also multiple editors here who believe this article is not balanced. That, alone, is sufficient to justify the "neutrality disputed" tag. We don't need consensus to add the neutrality-disputed tag, we need consensus to remove the neutrality-disputed tag. There is no doubt that the neutrality of this article is disputed, and there is no consensus for removing the tag.

Regarding observational data, note that the Argo buoys have shown no increase in ocean temperatures since the buoys were deployed (starting in 2000). In fact, they've shown a slight cooling trend. Now, that trend might not continue, but there've been enough buoys out there to have solid ocean temperature data for more than five years, and CO2 levels have been going up steadily the whole time. NCdave (talk) 17:01, 25 March 2008 (UTC)

Regarding your sources: (1) The NSIDC talks about clouds, not water vapor. Furthermore, it discusses the Arctic, and not the globe. Mark this one "reliable, but not relevant to the question at hand." (2) Perry Samson's lecture notes obviously are old (they reference the first IPCC report from 1990), and while he's a very smart guy, the notes aren't peer reviewed. Finally, please don't mix up clouds and water vapor like this guy tends to do. They should be discussed separately. Raymond Arritt (talk) 17:43, 25 March 2008 (UTC)

It should also be mentioned that Samson's notes also states that the WV feedback is positive:

lower tropospheric water vapor content

And then he goes into the cloud feedback, where he very specifically doesn't say whether there would be more clouds - or even if its a positive or negative feedback. (and that it would vary according to latitude). --Kim D. Petersen (talk) 18:16, 25 March 2008 (UTC)

Kim, you are right that there is uncertainty about the cloud cover extent, as well as its effects: some observational data casts doubt on the common assumption that increased surface (esp. ocean) temperatures will lead to increased clouds. Nevertheless, water vapor and clouds are very closely coupled, and need to be discussed together.

Raymond, as I noted, the NSIDC paper is about the Arctic, but it draws contrasts with the rest of the globe. Samson's page was last revised in 2005, according to archive.org, but that appears to have been just a formatting change; I think it dates from ~2003. But that's still not all that old, really.

Regarding the uncertainty about the feedback effects of water vapor & clouds, here are a few more sources. I'll start with RC, which says:

"Consistent with previous studies, clouds were found to provide the largest source of uncertainty in current models. For the most sensitive models, cloud feedback is positive and comparable in strength to the combined “water vapor plus lapse rate” feedback. For the least sensitive models, cloud feedback is close to neutral."

but also:

"studies that use the "cloud radiative forcing" calculation have reported a more negatively skewed 'cloud feedback' then[sic] seen here."[11]

Here are some recent lecture notes/slides from Joel Norris (Scripts & UCSD), for a paper currently under construction:[12] Some quotes:

"water vapor feedback is positive (probably)"

"low-level cloud -> cools the earth"

"high-level cloud -> warms the earth"

"sign of albedo cloud cover feedback is uncertain"

"sign of LW cloud cover feedback is uncertain"

"general theories do not exist for quantifying most individual climate feedbacks"

"competing climate processes cannot be distinguished using observations"

"models did not even agree on whether the net cloud feedback was positive or negative"

"the uncertainty range for projected global warming has not narrowed since 30 years ago"

With which of those statements do you folks disagree?

Here are a couple of other interesting sources.[13][14]

The bottom line is that even though most current models assume a net positive feedback effect for water vapor & clouds, the truth is that there is a great deal of uncertainty about that. NCdave (talk) 18:53, 25 March 2008 (UTC)

NCdave - Clouds are not water vapor. Clouds are condensed water vapor (ie. real water in droplets). Try making a distiction. --Kim D. Petersen (talk) 19:46, 25 March 2008 (UTC)

We have one section in the article that (inaccurately) discusses both forms of atmospheric water: humidity and clouds. The caption is "the role of water vapor," but I agree that that is not the best title. We should probably just drop the word "vapor." Clouds are made from (not of) water vapor. NCdave (talk) 13:52, 26 March 2008 (UTC)

I've changed the section caption to say "atmospheric water" rather than "water vapor." NCdave (talk) 13:57, 26 March 2008 (UTC)

And i've reverted, and cut the offensive 5 words that you apparently feel where NPOV (since they mention clouds in models). Is the section now satisfactory? --Kim D. Petersen (talk) 14:57, 26 March 2008 (UTC)

The article is about greenhouse gases. Discussing the role of clouds in the energy budget is beyond the scope the article, just like discussion of aerosols is beyond its scope. The argument over cloud feedbacks is irrelevant here. Jason Patton (talk) 15:53, 26 March 2008 (UTC)

Also, do you disagree with any of Joel Norris' statements that I quoted above? NCdave (talk) 13:52, 26 March 2008 (UTC)

Is there another wikipedia article on the greenhouse effect of clouds? If not perhaps this article should be modified to include them....if there is then a small note saying that clouds are not gaseous and therefore not a grenhouse gas and linking to it should suffice.

Although I agree with some of NCdaves points, my (main, there are other smaller problems too) argument on the neutrality of this article is that it has decended into a piece of pro-man-made-global-warming propaganda. For example the way it says 'humans are causing the levels of greenhouse gases to rise' over and over and over and over and over....I know it's probably true (I dispute anyone being 100% certain about it: always be willing to admit the possibility that you could be dead wrong), but that is no argument to have this article just keep going on about humans producing greenhouse gases and not give any other useful information about greenhouse gases. Restepc (talk) 17:06, 26 March 2008 (UTC)

Okay I've found http://en.wikipedia.org/wiki/Cloud_forcing

I suggest linking that article from the water vapour section (or at least explaining why clouds aren't mentioned there and putting it in see also) would be appropriate, I won't do it myself as Will has told be not to make bold edits on this page. Restepc (talk) 17:10, 26 March 2008 (UTC)

I disagree with this. Clouds aren't a greenhouse gas, which is after all the topic and title of the present article. People already have enough confusion between water vapor and clouds without us adding to it by mentioning clouds in the greenhouse gas article. Raymond Arritt (talk) 17:17, 26 March 2008 (UTC)

(edit conflict)Why should we explain that clouds aren't mentioned? Clouds aren't greenhouse gases. (which is what this article is about). And its linked in the box at the bottom. (or should be if not). --Kim D. Petersen (talk) 17:18, 26 March 2008 (UTC)

There's not a single molecule of water in a cloud that doesn't condense from water vapor. Clouds are what water vapor makes, and thus one of the main mechanisms through which water vapor affects warming and cooling.

The climate feedback from water vapor comes from multiple mechanisms, one of which is by feeding moisture to clouds. The "role of water vapor" is to create clouds. To discuss only how water vapor blocks the escape of IR (a positive feedback), and not how it creates clouds (quite possibly a negative feedback), is to bias the article to a particular POV.

Inasmuch as nobody is disputing the accuracy of Joel Norris' statements that I quoted above, I don't see how anyone can dispute the POV bias of this section's current text, since it does not reflect that uncertainty. A balanced article would corectly reflect the high level of uncertainty that exists about these mechanisms, rather than stating as fact things that experts say are just "probably" so or "uncertain," and rather than describing a positive feedback loop that is just plain wrong. NCdave (talk) 18:44, 26 March 2008 (UTC)

Clearly we disagree. Suggest you file a content RfC for wider input. Raymond Arritt (talk) 18:55, 26 March 2008 (UTC)

This is an article about greenhouse gases not about Radiative forcing or other factors impacting the Greenhouse effect. We also do not talk about Ocean acidification here - another rather important side-effect. We also don't go into how aerosols also cause Global dimming or how CO2 generation mechanism's also generate soot particles etc. etc.

Your question about Joel Norris' comments is a red-herring, i didn't comment on it - since it has no place here. This is not a generic discussion forum.

If you really think us that wrong - then i suggest you take RA's proposal, and start up an RfC. --Kim D. Petersen (talk) 19:06, 26 March 2008 (UTC)

"This is an article about greenhouse gases not about Radiative forcing or other factors impacting the Greenhouse effect. We also do not talk about Ocean acidification here - another rather important side-effect. We also don't go into how aerosols also cause Global dimming or how CO2 generation mechanism's also generate soot particles etc. etc."

I couldn't agree more with this sentiment, I very much agree that this article should stay strictly on the subject of greenhouse gases, however the fact remains that there is a lot of confusion among the general public between water vapour and clouds, and indeed they are closely linked to each other, and I think the article should explain that when it says water vapour, that doesn't include clouds, and it should at the very least have a link to the relative article on the effects of clouds Restepc (talk) 19:15, 26 March 2008 (UTC)

There is a link to it (in the navigation box at the bottom) as well as one to Ocean acidification, Aerosols etc etc. A lot of effects here are interlinked - and we deal with the subject by divide and conquer. --Kim D. Petersen (talk) 19:37, 26 March 2008 (UTC)

Ah so there is, I hadn't looked all the way down there, but I still think it needs explaining in the water vapour section, we know that clouds aren't a greenhouse gas, but the average guy on the street thinks water vapour=clouds Restepc (talk) 19:52, 26 March 2008 (UTC)

I'm going to try to fix this section, including a link to the Cloud forcing article. NCdave (talk) 19:24, 26 March 2008 (UTC)

Kim, you reverted me without comment, ao I've unreverted it. Please, if you have concerns, let's discuss them here. Okay?

For the convenience of other editors, here's it is:

The role of water vapor

Water vapor is a naturally occurring greenhouse gas and accounts for the largest percentage of the greenhouse effect, between 36% and 66% ^[1]. Water vapor concentrations fluctuate regionally, but human activity does not directly affect water vapor concentrations except at local scales (for example, near irrigated fields).

Current climate models assume that an increase in atmospheric temperature will in turn lead to an increase in the water vapor content of the troposphere (with approximately constant relative humidity), thereby amplifying the greenhouse effect of human-released greenhouse gases such as CO₂.^[2]

However, water vapor also feeds moisture to clouds, with climatic consequences that are not well understood. Clouds are the largest area of uncertainty in current climate models. It is not known whether clouds contribute negative or positive feedback to temperature changes. Depending on which models are correct, cloud feedback could almost halve or almost double the warming from other causes.^[3]^{[improper synthesis?]}

The beginning is unchanged from Kim's version. The 2nd paragraph is pruned down from her version; I replaced the problematic feedback loop description with the simple statement that increased water vapor from increased temperature is thought to amplify the greenhouse effect of human-released GHGs. The 3rd paragraph notes that water vapor feeds clouds, notes the uncertainty of climatic effects, and links to the Cloud forcing article. Would anyone care to discuss these changes, please? 20:11, 26 March 2008 (UTC)

I think most people have already expressed their opinion. Clouds are not greenhouse gases - and have their own article - its also not in any way or form clear if the total amount of water-vapor increases clouds - so its even a rather far-fetched connection. There are lots of other indirect factors that GHG's cause - these are also not discussed since this isn't the place. Both clouds and models have their own articles. Take it there.

These pages are not for general discussions on climate change. There are other forums for that. --Kim D. Petersen (talk) 20:26, 26 March 2008 (UTC)

I've marked the section above with improper synthesis - since you are implying that increased water vapor, will increase the amount of clouds, and by context it indirectly states that models also make this assumption. This is not supported by any of your sources. (nor by the IPCC 4AR, or observations (iirc)). --Kim D. Petersen (talk) 20:33, 26 March 2008 (UTC)

Perhaps

"Current climate models show that an increase in atmospheric temperature will in turn lead to an increase in the water vapor content of the troposphere, with approximately constant relative humidity. The increased water vapor in turn leads to an increase in the greenhouse effect and thus a further increase in temperature; the increase in temperature leads to still further increase in atmospheric water vapor; and the feedback cycle continues until equilibrium is reached. Thus water vapor acts as a positive feedback to the forcing provided by other greenhouse gases.

Clouds are made from water vapour, but not of water vapour, and therefore the effects of clouds are considered seperate from the effects of water vapour, see Cloud forcing" Restepc (talk) 21:00, 26 March 2008 (UTC)

Kim, you've done four reverts[15][16][17][18] today, in violation of WP:3RR, the last of them immediately after being warned that you had already made three. All for were full reverts, done by clicking on "undo," and none were reverting clear vandalism.

Yes - you've now mentioned this (3RR) 4 times. Once in revert comment - once on my talk - once on you're own talk - and finally here. And my response is the same: 1 of the reverts was a reversion of vandalism (which doesn't count). If you feel that you want to press this - then take it to WP:AN/3 instead of harping on about it. Start addressing the edits/discussion - not the editor. I find this rather annoying. If i did something wrong - then i'm willing to face the consequences - but frankly i don't think i did. --Kim D. Petersen (talk) 21:44, 26 March 2008 (UTC)

Also, I do not understand how you can think that mentioning water vapor's role in creating clouds is off-topic for a section entitled "the role of water vapor." Do you question the fact that the water of which clouds are composed comes from atmospheric water vapor?

This is neither an article about Water vapor nor an article about Cloud forcing - what we are supposed to cover - is water vapors role as a greenhouse gas. Clouds are not part of that. --Kim D. Petersen (talk) 21:47, 26 March 2008 (UTC)

Also, what do you think is synthesis? Only you have expressed such a concern. The conclusion that "cloud feedback could almost halve or almost double the warming" is directly from Samson, whom I quoted above saying, ""Currently it is not known whether the total effect of these changes will be a negative or positive feedback" ... "Depending on whether and how cloud cover changes, the cloud feedback could almost halve or almost double the warming." That is certainly not synthesis.

You said, "This is not supported by any of your sources." I can only assume that you overlooked it, though I quoted it here.

Also, I'd like to know why you reverted the second paragraph? Nobody has expressed any concerns about that. NCdave (talk) 21:25, 26 March 2008 (UTC)

I've explained why its a synthesis. Clouds (fewer or more) are not a feedback of increased water vapor content. You are implying that this is the case - and also that models consider it so. That aside - you are also not faithfully reflecting what Samson's article is saying. Clouds belong in their own article - not here. --Kim D. Petersen (talk) 21:42, 26 March 2008 (UTC)

Kim, here's another quote from one of the sources I cited above: "It is thought that if climate warms, evaporation will also increase, in turn increasing cloud cover."[19][20] Does that address your concern? NCdave (talk) 22:12, 26 March 2008 (UTC)

Which both address the Arctic - and not the globe. RA has already pointed this out to you. (did you forget?). I've just scanned IPCC chapter 8 for information on this - and such an effect is not described (for either models nor observations). --Kim D. Petersen (talk) 22:18, 26 March 2008 (UTC)

Restepc, I think we're all agreed on the first paragraph (Kim's wording).

Your last paragraph seems like a reasonable compromise, to me, too. It doesn't say nearly as much as I think it should, but what it does say is correct. I can accept it. (Kim, will you accept it?)

But the middle paragraph still has that problematic runaway feedback description. That's just plain wrong. How about this?

Water vapor is a naturally occurring greenhouse gas and accounts for the largest percentage of the greenhouse effect, between 36% and 66%.^[4] Water vapor concentrations fluctuate regionally, but human activity does not directly affect water vapor concentrations except at local scales (for example, near irrigated fields).

Current climate models assume that an increase in atmospheric temperature will in turn lead to an increase in the water vapor content of the troposphere (with approximately constant relative humidity), thereby amplifying the greenhouse effect of human-released greenhouse gases such as CO₂.^[5]

Clouds are made from water vapor, but not of water vapor, and therefore the effects of clouds are considered separately from the effects of water vapor, see Cloud forcing."

That's not what I would write, but it is enormously better than the current section.

There's also a certain attractive "political" balance to it: the first paragraph is Kim's, the second is mine, and the last is yours -- very much in the spirit of compromise. :-) NCdave (talk) 21:59, 26 March 2008 (UTC)

In the second paragraph, "assume" is incorrect ("predict" would be better). The third paragraph is terribly awkward; perhaps "Clouds are composed of liquid or frozen water, and therefore the effects of clouds are physically different from the effects of water vapor. See Cloud forcing." Raymond Arritt (talk) 22:05, 26 March 2008 (UTC)

Both of those changes are acceptable to me, Raymond. NCdave (talk) 22:14, 26 March 2008 (UTC)

I'd agree with Daves version including Rays suggested edits, with one exception.

where it currently says "thereby amplifying the greenhouse effect of human-released greenhouse gases such as CO₂" I would prefer "thereby amplifying the greenhouse effect of other greenhouse gas emissions", as it is misleading to suggest that the effect would somehow apply to molecules of CO2 that came from human sources, but not to molecules of CO2 that came from natural sources Restepc (talk) 22:18, 26 March 2008 (UTC)

Seems reasonable to me. --Kim D. Petersen (talk) 22:27, 26 March 2008 (UTC)

Me too. NCdave (talk) 22:43, 26 March 2008 (UTC)

I've just made the changes to the article. Thank you, everyone, for working together on this! NCdave (talk) 22:51, 26 March 2008 (UTC)

In the end all we really accomplished was removing an intuitive explanation of how the positive feedback process works. So we reached an agreement, but the article is worse. Raymond Arritt (talk) 22:56, 26 March 2008 (UTC)

Yep. Not to start the debate up again though - but shouldn't we change the "models" part to a mention that the Clausius-Clapeyron relation says that WV content should increase 7% for each 1°C of warming? That is after all the reason that the models predict this. (if i'm not mistaken) --Kim D. Petersen (talk) 23:12, 26 March 2008 (UTC)

Yeah, the CC eqn is what I had in mind in my earlier comment about "basic principles." At least we got rid of the utterly wrong "assume." I never know how much technical detail to go into when responding to these comments (or when editing articles). Maybe I'll try to think of a way to phrase it that's accurate yet still understandable to someone who hasn't learned about Gibbs free energy... Raymond Arritt (talk) 00:38, 27 March 2008 (UTC)

Kim, it is reasonable to add such information, but I think it is the Goff-Gratch equation or Arden Buck Equation to which we should refer. NCdave (talk) 08:10, 27 March 2008 (UTC)

Raymond, we removed a wrong explanation of the feedback process, we made the prose tighter and cleaner, and we added a link to some very closely-related information about clouds. Also, we managed to work together, for a change, which is an excellent precedent. The section is not all I think it should be, but at least it is now accurate, which it wasn't before. All in all, a good bit of work accomplished. NCdave (talk) 08:10, 27 March 2008 (UTC)

No. The Clausius-Clapeyron equation is basic physics. The Goff-Gratsch and Buck equations are simply two among many empirical fits to data and provide no insight into how the world works. (In fact I'm amazed that something as trivial as the Buck equation has its own article.) There's no more reason to cite those than Teten's equation or Lowe's polynomials or Bolton's equations or any of the other empirical fits. I disagree with you on all your other points, but will defer to your superior understanding of the physics involved. Raymond Arritt (talk) 14:01, 27 March 2008 (UTC)

Strictly speaking, referencing CC alone is insufficient. CC tells you about the change in the maximum water vapor content an air mass can support as a function of temperature. Since most air masses are undersaturated with respect to water vapor, you still need dynamical models to tell you how changes in the maximum humidity before precipitation will impact the average humidity. Dragons flight (talk) 23:30, 27 March 2008 (UTC)

Water Vapour

The old version 'prefered' by Will, Kim, and Ray reads

"Water vapor is a naturally occurring greenhouse gas and accounts for the largest percentage of the greenhouse effect, between 36% and 66% [12]. Water vapor concentrations fluctuate regionally, but human activity does not directly affect water vapor concentrations except at local scales (for example, near irrigated fields).

Current state-of-the-art climate models show that an increase in atmospheric temperature caused by the greenhouse effect due to anthropogenic gases will in turn lead to an increase in the water vapor content of the troposphere, with approximately constant relative humidity. The increased water vapor in turn leads to an increase in the greenhouse effect and thus a further increase in temperature; the increase in temperature leads to still further increase in atmospheric water vapor; and the feedback cycle continues until equilibrium is reached. Thus water vapor acts as a positive feedback to the forcing provided by human-released greenhouse gases such as CO2.[13]"

The modified version we agreed upon last night but now suddenly is out of favour

"Water vapor is a naturally occurring greenhouse gas and accounts for the largest percentage of the greenhouse effect, between 36% and 66%.^[6] Water vapor concentrations fluctuate regionally, but human activity does not directly affect water vapor concentrations except at local scales (for example, near irrigated fields).

Current climate models predict that an increase in atmospheric temperature will in turn lead to an increase in the water vapor content of the troposphere (with approximately constant relative humidity), thereby amplifying the greenhouse effect of other greenhouse gas emissions.^[7]

Clouds are composed of liquid or frozen water, and therefore the effects of clouds are physically different from the effects of water vapor. See Cloud forcing."

My proposed new version (always feel free to correct my poor grammar)

"Water vapor is a naturally occurring greenhouse gas and accounts for the largest percentage of the greenhouse effect, between 36% and 66% [12]. Water vapor concentrations fluctuate regionally, but human activity does not directly affect water vapor concentrations except at local scales (for example, near irrigated fields).

An increase in atmospheric temperature caused by the greenhouse effect will in turn lead to an increase in the water vapor content of the troposphere, with approximately constant relative humidity. The increased water vapor in turn leads to an increase in the greenhouse effect and thus a further increase in temperature; the increase in temperature leads to still further increase in atmospheric water vapor; and the feedback cycle continues until equilibrium is reached. Thus water vapor acts as a positive feedback to the forcing provided other greenhouse gases.[13]

Clouds are composed of liquid or frozen water, and therefore the effects of clouds are physically different from the effects of water vapor. See Cloud forcing."

Points of contention, numbered for ease of discussion:

1) The disambig of cloud forcing.....I really can't see the problem with this, it appears an open and shut case.....although we know that water vapour and clouds aren't the same thing, many people who erad this article won't. Does anyone actually have an objection to that last paragraph and if so what on earth is it?

2) saying man-made gases a lot.....this relates to my problem with the whole article, as I said last night it is misleading to suggest that water vapour acts as a positive feedback just to man made CO2 molecules, but not to naturally formed ones....

3) climate models Show/assume/predict....I think assume is obviously out as it sounds very POV against climate models, and I don't think we should have 'show' as that is a claim that climate models are infalliable.....Ray suggested predict, which I think is perfect.

Again, the objection to "assume" is not that it's POV, but that it's wrong. Models don't assume this. Raymond Arritt (talk) 23:04, 27 March 2008 (UTC)

4) Whether or not to include the more detailed explanation of feedback, although the modified version of last night didn't....I think I'm right in saying that everyone now agrees that it should be included....right?

There are a few other small things I personally have a problem with as well, but I'll leave them for another time......Restepc (talk) 22:35, 27 March 2008 (UTC)

1. I've already stated earlier, that i don't see what clouds have to do in this article. There are lots of things that people reading this article may not know. Thats why we have the nav-box at the bottom.

2. "man-made" is not used a single time. On the other hand "human released" is mentioned once - and since we know that the increase in other gases indeed is because of human release - its appropriate.

3. As mentioned earlier - models show this because of physics, more precisely the Clausius-Clayperon relation. We would calculate this even if there were no models to guide us, 1°C => ~7% more water vapor. Its not a question of "infallible" models - or even "fallible" ones, personally i don't think it needs a mention of models at all.

4. Yep. (except NCdave i presume).

--Kim D. Petersen (talk) 22:54, 27 March 2008 (UTC)

4, agreed, 3....now that I think about it removing the sentence about models entirely sounds like a great option. 2...that's kinda splitting hairs, I'm sure you knew what I meant, and no it is not appropriate, it gives the incorrect impression that water vapour only acts as a feedback to anthroGHGs.

1...yes we've discussed this before, and I think I'm struggling to get my point across to you.....clouds aren't a part of this article:that is my point. There are a lot of things that people don't know about (including the existence of a nav box at the bottom in many cases), and the whole purpose of this article is to inform them about greenhouse gases, which I think includes telling them that clouds aren't one. My point rests on three basic things: most people think that water vapour=clouds, the article currently doesn't tell them otherwise, therefore most people will think the water vapour section is talking about clouds. Restepc (talk) 23:14, 27 March 2008 (UTC)

Dragons edit looks good to me: if the cloud disambig is added Restepc (talk) 23:29, 27 March 2008 (UTC)

Could we get a third opinion on cloud disambig? Restepc (talk) 18:11, 4 April 2008 (UTC)

Wikiproject Earth

Hello i have recently proposed the Wikiproject Earth. This Wikiproject`s scope includes this article. This wikiproject will overview the continents, oceans, atsmophere and global warming Please Voice your opinion by clicking anywhere on this comment except for my name. --Iwilleditu ^Talk :)^{Contributions} —Preceding comment was added at 15:37, 30 March 2008 (UTC)

cattle

Can anyone tell me why this

"Atmospheric scientist Ralph Cicerone, a chancellor at the University of California, Irvine indicates "Methane is the second-most-important greenhouse gas in the atmosphere now. The population of beef cattle and dairy cattle has grown so much that methane from cows now is big. This is not a trivial issue." ^[8]. Approximately 5% of the methane is released via flatulence, whereas the other 95% is released via eructation. Vaccines are under development to reduce the amount introduced via eructation. ^[9]"

was reverted out with no apparent discussion? What's the objection to it? Restepc (talk) 18:10, 4 April 2008 (UTC)

Yes, Two successive edits were reverted without explanation. Why? Plantsurfer (talk) 18:46, 4 April 2008 (UTC)

Do the obvious and look up the user in question. BTW, its better to put in a link to a diff than to quote. If you want to sponsor the text, put it in William M. Connolley (talk) 10:19, 5 April 2008 (UTC)

I have restored the deleted contribution on methane by Victim of Changes. It has its faults, in particular it is not in the most encyclopaedic form, so modification may be required, but please don't simply rub it out without justification. Plantsurfer (talk) 10:56, 5 April 2008 (UTC)

Its a shame that you've chosen to sponsor this text, because its poor. That the source title is "Bovine Belching Called Udderly Serious Gas Problem" might be taken as a bit of a hint. That it comes from "mycattle.com" might also be a bit of a hint that this is not unbiased. If you want to provide some basic text as to where the current sources of methane are, then a quick look at - guess where? yes thats right - methane - will provide some more useful info William M. Connolley (talk) 14:59, 5 April 2008 (UTC)

I think we need a new tag for articles like this: "This article reflects the dominant mainstream view of the subject, and my word but do some people hate that". Guy (Help!) 21:37, 11 April 2008 (UTC)

Victim of Changes

On further investigation I find that Victim of Changes is a now-blocked sockpuppet of indefinitely blocked user Scibaby. Plantsurfer (talk) 11:24, 5 April 2008 (UTC)

Apparently, Glare_of_the_Midnight_Sun is another one, and he's now blocked, and his contribution was insta-reverted. However, I think his contribution is worth another look:

Research by NASA climate scientist James Hansen indicates the 0.75° rise in average global temperatures over the last 100 years has been driven mainly by greenhouse gases other than carbon dioxide.^[10]

I realize that Hansen is not the most popular fellow around here, but this appears to be well-sourced, solid research. I don't know that the place where Glare put it was the best location, but surely it belongs somewhere in the article. NCdave (talk) 16:10, 15 April 2008 (UTC)

In proper form, possibly. But not in the misleading way that Scibaby/whoever always presents it. Raymond Arritt (talk) 16:14, 15 April 2008 (UTC)

Human methane emissions

I estimate methane emissions in human fart at about 1.7 M tonnes per annum allowing a comparatively modest ~1 litre output per person per day (more in bean-eating areas). Given that methane is 23 times more potent as greenhouse gas than CO
₂, the anal afterburner is probably an invention waiting to happen. Thought you might like to share this. Have a nice day! Plantsurfer (talk) 10:53, 6 April 2008 (UTC)

Abundance / power

I'm not sure this [21] helps, or is even correct William M. Connolley (talk) 19:55, 28 April 2008 (UTC)

The original wording was better; e.g., "powerful" is an odd adjective to use here. The bulleted list is awkward. Raymond Arritt (talk) 20:00, 28 April 2008 (UTC)

Once again, the debate is quashed.

I find it quite disconcerting that, depite claims of scientific merit, any edits to this article that question the human role in global warming are consistently deleted, while statements claiming scientific fact even while a scientific discord exists, are left in without question. Is this the way to come to an educated conclusion on any topic? —The preceding unsigned comment was added by 63.237.28.3 (talk) 19:09, 15 May 2007 (UTC).

It was removed (it would seem) because it was an example of false logic. The global warming issue centers on the very real, observed, and obvious increase in release of CO₂ into the atmosphere by the combustion of fossil fuels and the consequent increase in atmospheric CO₂. At best the removed material shows evidence that there is a positive feedback mechanism that magnifies the effect of any warming from any cause. The logical approach would be to evaluate the positive feedback effect on the warming caused by the added atmospheric CO₂. The illogical approach is to misuse the data to support claims that the CO₂ released from the combustion of fossil fuels has no effect. If you want "educated conclusion" more power to you. What was removed wasn't that.

I have no idea what was removed or kept. I do know that using false data like temperature measurements at Airports is not real though observed. The increase in CO2 in the atmosphere is not obviously man made. You want it to be to make your case stick. The logical approach is not to make an incorrect assumption and then force everyone else to believe. The logical approach is to use scientific reasoning to make an argument not 'entry deletion' which is so prevalent. (Jarl87 (talk) 20:55, 2 May 2008 (UTC))

(The comment below applies to the text above.) Minasbeede 15:38, 1 June 2007 (UTC)

No, it's not. Invasion10 08:56, 17 May 2007 (UTC)

Automatic archiving

I added automatic archiving to this page? there was a lot of old discussions lying around, not being useful. I hope no one mind?
– Apis (talk) 16:28, 15 May 2008 (UTC)

Increase rate graph

[Retitled section for accuracy; was "Rate increase graph" New Image Uploader 929 (talk) 03:20, 30 May 2008 (UTC)]

I made a graph for the "Long term trends" section but I'm not allowed to upload it yet. New Image Uploader 929 (talk) 18:28, 13 May 2008 (UTC)

I took out your new text [22]. Sorry. I'd like to see a better source... also it doesn't seem very consistent with the graph at the top or with Image:Major_greenhouse_gas_trends.png. Also these are not rates - fractions - but absolute increments. There ought to be a good source discussing this that you could quote, though William M. Connolley (talk) 19:39, 13 May 2008 (UTC)

What is a better source for this data than the NOAA Mauna Loa observatory? I am adding Dr. Tans' paper cited at the end of the web page. If you look at 1998 on Image:Major greenhouse gas trends.png, you will see that the red line is steepest in 1998, just like the delta is largest in 1998 on my plot. The data are both increases in the proportion (fraction) of air, and rates of change, because they are the year-to-year deltas. If that is not correct, please tell me why. I hope you like the new version. New Image Uploader 929 (talk) 02:02, 15 May 2008 (UTC)

Is this is your own conclusion from the data? If that's the case there should probably be a better reference (something more explicit)? Also, that graph is that taken from the NOAA webpage? that could be copyright violation, although I know very little about how that works.
— Apis (talk) 16:35, 15 May 2008 (UTC)

From the graph in the image the rate looks pretty constant to me (1980-2004)? Although if you look at the image at the top of the page there is a definite change in the curve around 1950. Anyway, maybe thats why I'm a bit confused.
— Apis (talk) 22:05, 15 May 2008 (UTC)

I added the image to the right. It does not look constant to me. It looks consistent with an exponential increase, but since true exponentials can not exist in a proportion domain, it is probably a logistic curve with a non-unity maximum, I hope. New Image Uploader 929 (talk) 00:35, 30 May 2008 (UTC)

Would it be advisable to overlay a linear regression line? New Image Uploader 929 (talk) 03:09, 30 May 2008 (UTC)

Better not fit to a second order model; it looks like a return to 0ppm in about 2040. Wouldn't want to present any inconvenient projections, now would we? blackcloak (talk) 05:02, 7 June 2008 (UTC)

Subjective and incorrect

'However, an excess of greenhouse gases can raise the temperature of a planet to lethal levels,'

Historically, and scientifically notated, CO2 levels ALWAYS follow global warming and have never been a cause of it. Methane is >20x more potent than CO2 and there is billions of tons of it frozen under the sea. Occasionally this belches to the surface. Also, during the Dinosaur era, CO2 was something like 4-10x the levels of today and yet the global average temp was estimated to be ~4 DegC higher.

'as on Venus where the 96.5% carbon dioxide (CO2) atmosphere results in surface temperatures of about 467 °C (872 °F)'

Totally irrelevant - there are so many other factors involved here. 2nd planet closest to the Sun with an atmosphere 92 times that of Earth. The pressure alone may well account for a considerable amount of temperature. In fact, using the "Combined Gas Law" [23] the temperature (unless my calculations are very wrong and based on Earth's temp 15 degC (ICAO Standard Temp) and volume of 1) it's temperature based on pressure alone should be ~1380 degC - let alone it's proximity to the Sun. Wawny (talk) 23:27, 3 June 2008 (UTC)

Do you have any reliable sources (scientific) for these claims?
—Apis (talk) 01:35, 4 June 2008 (UTC)

Clearly you don't know how to apply gas laws to this situation. Indeed, you can not because temperature equilibrium (black body radiation) has been achieved. You've probably calculated some temperature based on an instantaneous change in pressure, ignoring heat sources and radiative cooling. Here are some relevant considerations. Venus has no significant magnetic field so charged particulates bombard the atmosphere. These may contribute significantly to the energy received by the atmosphere, along with its molecular dissociative properties. This factor in not normally considered because the flux entering earth's atmosphere does not include a charged particle component. An atmosphere 92x earth's pressure means pressure broadened absorption. The 5% non CO2 content (partial pressure) is still 5x more than the earth's pressure, so that component alone might absorb something like (1-.7^5)/(1-.7)=2.8 times the incoming solar power of the earth. Multiply that by 2 because Venus receives approx 2x the power density of the earth and the result is almost 6x the solar power absorbed by earth is absorbed by the atmosphere of Venus- just due to the 5% non CO2 component. The CO2 is 18 times more important, at least in the absorption bands of CO2. Result is essentially no light any where near an absorption band of CO2 is going to make it to the surface. It is fairly safe to say that much of the surface temperature of Venus is due to solar radiation cooking the atmosphere, which in turn heats the surface. My guess is that only a few degrees of surface temperature can be attributable to thermal energy reaching the surface from heat deep within the planet. 92 times 14.7psi on earth means 1350 pounds of atmospheric stuff above every square inch of the surface of Venus. On earth, this would be like the pressure conditions experienced at a depth of 2800 feet below the sea surface level. (All quick back of the envelope calculations, so errors may have crept in.) blackcloak (talk) 06:16, 5 June 2008 (UTC)

As I recall, Venus's albedo is higher than Earths, so the solar in is about the same as Earth, even though its closer to the sun. The energy in charged particles is likely trivial compared to viz. You can't do radiative-xfer on the back of an envelope William M. Connolley (talk) 06:49, 5 June 2008 (UTC)

The "solar in" is still 2x (measured in watts per meter squared) that of earth. What leaves, and from where, (the albedo component, something I did not discuss) is another story. In equilibrium, total power in is equal to total power out (assuming we can neglect any heat contribution originating from within the planet). Since Venus has such an incredibly dense atmosphere, we can pretty easily conclude that only an insignificant amount of incoming solar radiation passes through the atmosphere and reaches the surface without scattering or absorption followed by black body re-emission. Actually "you" can do radiative xfer calculations on the back of an envelope. I just did. Perhaps you can't. But then you are free to do the more precise calculations and present your results- and if they look reasonable, I'll accept them. Not a problem. blackcloak (talk) 05:40, 6 June 2008 (UTC)

Venus

I'm happy with a brief mention of the pressure [24] though I don't think long details are appropriate of insolation, albedo, etc William M. Connolley (talk) 10:28, 29 June 2008 (UTC)

Greenhouse effect dependent on location?

Someone removed "The effect of a gas also depends on its location. For example, ozone is a greenhouse gas only in the upper troposphere." Is that not correct, then? I thought it was. And the same for water vapour, if I remember correctly. DirkvdM (talk) 10:39, 1 July 2008 (UTC)

This Page is Confused

Sorry, I can't remember my pw right now, so I'm doing this anon. This entry is Greenhouse Gas, but most of it is not about greenhouse gases, but about increased levels of CO2. Either the entry needs to more generally discuss all greenhouse gases and leave out the measured change in CO2 over time, or it needs to be retitled to reflect its focus on the measured increase of CO2 and how this contributes to global warming. —Preceding unsigned comment added by 170.202.222.1 (talk) 22:49, 1 July 2008 (UTC)

Citations?

I wish the charts and graphs all had proper citations. I am highly skeptical of the accuracy of the data represented in some of them. I am also astounded at the general lack of citations (or "references") provided in this article. Healthylaw (talk) 01:21, 12 July 2008 (UTC)

You need to click on the image to get the detailed description and reference info. Dragons flight (talk) 03:52, 12 July 2008 (UTC)

PHEV

Someone is adding "[citation needed]" to the PHEV intro, about "may cause global warming." Wasn't that decided already? 76.235.158.200 (talk) 11:01, 13 July 2008 (UTC)

Unfortunate bias here

I am very disappointed to find such a slanted article here (for example, using Venus as a relative comparison to Earth, and suggesting its high CO2 levels as the cause of its high temperature). The section of 'Natural' greenhouse production is yet another glaring case of bias. I mean, is the wikipedia community actually saying that the natural emissions of CO2 into the atmostphere are negligible?? ALL rotting biological material and ALL living creature's excrement emit methane, a much more potent greenhouse gas. From reading the section on natural greenhouse gas production, one is left with the impression that it is a negligible influence. A very disappointing article.

Let me second that emotion. POV is clearly biased toward current "consensus" that human activity is driving alleged global warming. Folks, this is a theory which is already beginning to show some wear-and-tear. It is not the last word on climate, its uses and abuses. Captqrunch (talk) 15:30, 23 July 2008 (UTC)

CO2 and greenhouse gases

Can someone explain to me how CO2, which weighs 1.5 times more than air, gets sustained in the upper atmosphere? Thanks. Captqrunch (talk) 15:34, 23 July 2008 (UTC)

By convective mixing and diffusion. Air is just constantly on the move, and it just doesn't

get the chance to settle out. Even in a compressed air cylinder you don't get the CO2 forming a layer at the bottom. Plantsurfer (talk) 16:14, 23 July 2008 (UTC)

More specifically, gases cannot unmix by molecular weight because the molecular mean free path -- roughly, the distance between molecules -- is much smaller than the scale of bulk motions in the troposphere and stratosphere. Only in the far upper atmosphere (above 80 km or so) does the mean free path become long enough that gases stratify by molecular weight. Short Brigade Harvester Boris (talk) 05:08, 9 August 2008 (UTC)

Black Balloons

Recent climate change articles from Australia refer to black balloons as an analogy for 1 tonne of carbon offsets or emissions. Has this been inserted into any articles on Wikipedia, or is it a relevant term to be adding to Wikipedia as it’s a regional term only? http://www.abc.net.au/news/stories/2009/08/07/2649513.htm Amckern (talk) 02:27, 7 June 2010 (UTC)

^ realclimate.org. Water vapour: feedback or forcing?.
^ Held, Isaac M.; Soden, Brian J. (2006), "Robust Responses of the Hydrological Cycle to Global Warming" (PDF), Journal of Climate, 19 (21): 5686–5699, doi:10.1175/JCLI3990, retrieved 2007-07-11 {{citation}}: Cite has empty unknown parameter: |1= (help)
^ Feedback Mechanisms in Climate, Perry Sampson, Associate Chair and Professor Department of Atmospheric, Oceanic and Space Sciences, University of Michigan (lecture notes)
^ realclimate.org. Water vapour: feedback or forcing?.
^ Held, Isaac M.; Soden, Brian J. (2006), "Robust Responses of the Hydrological Cycle to Global Warming" (PDF), Journal of Climate, 19 (21): 5686–5699, doi:10.1175/JCLI3990, retrieved 2007-07-11 {{citation}}: Cite has empty unknown parameter: |1= (help)
^ realclimate.org. Water vapour: feedback or forcing?.
^ Held, Isaac M.; Soden, Brian J. (2006), "Robust Responses of the Hydrological Cycle to Global Warming" (PDF), Journal of Climate, 19 (21): 5686–5699, doi:10.1175/JCLI3990, retrieved 2007-07-11 {{citation}}: Cite has empty unknown parameter: |1= (help)
^ http://www.mycattle.com/health/dsp_health_article.cfm?storyid=10045
^ http://www.newscientist.com/article.ns?id=dn6431
^ http://www.pnas.org/cgi/content/full/97/18/9875

[1] realclimate.org. Water vapour: feedback or forcing?.

[2] Held, Isaac M.; Soden, Brian J. (2006), "Robust Responses of the Hydrological Cycle to Global Warming" (PDF), Journal of Climate, 19 (21): 5686–5699, doi:10.1175/JCLI3990, retrieved 2007-07-11 {{citation}}: Cite has empty unknown parameter: |1= (help)

[3] Feedback Mechanisms in Climate, Perry Sampson, Associate Chair and Professor Department of Atmospheric, Oceanic and Space Sciences, University of Michigan (lecture notes)

[4] realclimate.org. Water vapour: feedback or forcing?.

[5] Held, Isaac M.; Soden, Brian J. (2006), "Robust Responses of the Hydrological Cycle to Global Warming" (PDF), Journal of Climate, 19 (21): 5686–5699, doi:10.1175/JCLI3990, retrieved 2007-07-11 {{citation}}: Cite has empty unknown parameter: |1= (help)

[6] realclimate.org. Water vapour: feedback or forcing?.

[7] Held, Isaac M.; Soden, Brian J. (2006), "Robust Responses of the Hydrological Cycle to Global Warming" (PDF), Journal of Climate, 19 (21): 5686–5699, doi:10.1175/JCLI3990, retrieved 2007-07-11 {{citation}}: Cite has empty unknown parameter: |1= (help)

[8] ttp://www.mycattle.com/health/dsp_health_article.cfm?storyid=10045

[9] ttp://www.newscientist.com/article.ns?id=dn6431

[10] ttp://www.pnas.org/cgi/content/full/97/18/9875

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