Talk:Greenhouse gas

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/archive_1 Carbon Dioxide - the evil villian that is creating a new industry The information contained in this article seems to be selective. We all know that the use of cars and burning of fossil fuels produced carbon dioxide our most hated green house gas. The question is if carbon dioxide is 1.5 times heavier than air which is a fact as opposed to a theory, how is it rising to the upper atmosphere and keeping heat in ?

Common Mr Gore answer that one, or is this Mr Gore's inconvenient truth. —Preceding unsigned comment added by 124.189.51.232 (talk) 09:26, 15 October 2007 (UTC)

It's good to ask questions. There are answers. (P.S. Check out the phenomenon called weather and the feature of weather called wind.)

That's not quite as ignorant a question as it could be. In the past there have been deaths from people going down into unused wells to work on them, with the death being from the lack of oxygen because of the carbon dioxide that had diffused out of the earth and collected in the well. Just read (somewhere) that simply throwing a couple of buckets of water down the well would stir up the air inside enough to eliminate the problem. Nowadays who among us would even be aware of that potential problem? --Minasbeede 14:10, 15 October 2007 (UTC)

Man made sources

I think this article should include a graph showing the man made sources of green house gases against the natural sources of green house gases.

71.28.213.24 01:26, 26 March 2007 (UTC)

It could, but do not be deceived (and do not deceive others) on this point. The global warming problem is a result of fossil carbon being introduced into the biosphere by man (who mines and burns fossil fuels.) Methane from lakes (and cows) is from existing biosphere carbon. Such methane still matters. In addition the lake methane and (in particular) the cow methane may also be attributed to human activity.

There's a huge contribution to greenhouse gases by the natural decay of plant material. Since that's just biosphere carbon recycling again and again it's not the same as the fossil carbon. (If plants could extract the excess carbon as carbon dioxide from the atmosphere rapidly enough - and if that carbon stayed as plant material - then we'd not have as severe a problem.)

Minasbeede 02:39, 11 April 2007 (UTC)

Percentage increase

What does the percentage increase in the table within the section Increase of greenhouse gases refer to? 85.124.182.40 15:10, 19 August 2005 (UTC)

The 1750 baseline, which isn't given separately (the 1998 level and the change from 1750 are). It might be clearer to have the baseline as well as, or even instead of, the 1750-1998 change. Rd232 18:14, 19 August 2005 (UTC)

Why does the top graph go from right-to-left?

Didn't someone just fix that backward graph somewhere else? --James S. 19:04, 28 December 2005 (UTC)

Why not, the axis is labelled. And the net sink bit comes directly from the red/blue line crossover at abt. 1900. Seems sensible to me, what shenanegans are you referring to in that edit summary? Vsmith 21:29, 28 December 2005 (UTC)

Why are all the other graphs going in the other direction? Is there even a single peer-reviewed scientific journal in the English language which publishes time series graphs from right to left? Dragons flight is certainly capable of producing canonical graphs, and I wonder why the prominently displayed images are the only ones with reversed x-axes.

As for net sink, the system used to be in equilibrium. I'm sure you won't mind if I change that to the corresponding "net source" description of artificial sources. —James S. 00:25, 29 December 2005 (UTC)

The red/blue distinction is between fossil fuel and total change, not natural and artificial. —James S. 00:32, 29 December 2005 (UTC)

Dipole

Someone needs to change the line about dipole moments. The problem is that it should either simply say that they cannot absorb light in the IR region, or get fairly technical to explain why. The solution is to probably reference a page or a stub which goes into why. I will think about writing this, however, if it is to be done, how can the top of the page be changed?

Dipoles goes beyond me - sounds like you should be fixing it! And... go edit your user page Josh! William M. Connolley 17:34, 16 January 2006 (UTC).

Global warming potential (again)

I have come a bit late to the issue of whether GWP should be here or not. I have been trying to improve the GWP page which lead me here. I noticed that the section here was now mainly on lifetimes of GHG so I renamed the section and added a small summary on GWP with a link to that page. I think this now works better. Feel free to disagree though..--NHSavage 21:31, 19 January 2006 (UTC)

I meant to remove all the GWP figures from the section on lifetimes. I have now done this. There is a more complete table of figure on GWP in that article

Role of WV

In a comment to [1], Andrew Lacis wrote some stuff that might be useful here one day, so I'll record it before I forget where I read it:

The first statement of the punching bag quote that the combined effect of terrestrial greenhouse gases is to warm the surface of the Earth by 33 C is basically correct. The second statement that 95% of this warming is produced by water vapor is clearly erroneous. Of the 33 C greenhouse effect, about 10-11 C is due to non-volatile greenhouse gases (i.e., gases that do not precipitate out from the atmosphere for the typical range of atmospheric temperatures). These non-volatile greenhouse gases are CO2, CH4, N2O, ozone, and CFCs. If the Earth's atmosphere were totally devoid of water vapor, these non-volatile GHGs would support a surface temparature 10-11 C warmer than the -18 C equilibrium baseline (which corresponds to no atmospheric greenhouse effect). The rest of the 33 C greenhouse effect is due to feedback effects of water vapor which is a reaction to the radiative forcing due to the non-volatile GHGs and accounts for roughly half of the 33 C greenhouse effect, and clouds which provide roughly 6-7 C. As a crude analogy, the non-volatile greenhouse gases serve as a "skeleton" upon which vater vapor (and cloud) feedbacks can operate. (A horse without a skeleton upon which its muscles can exert their force would be laying sprawled out flat on the ground.) Accordingly, if the non-volatile GHGs (CO2, CH4, N2O, O3, CFCs) were removed from the atmosphere, the atmospheric water vapor and clouds would precipitate from the atmosphere, and the resulting surface temperature would drop to the basline -18 C value. In this over-simplified model, the non-volatile greenhouse gases (CO2, CH4, N2O, O3, CFCs) provide an overall radiative forcing of about 11 C. The volatile component (water vapor and clouds) operate in teh current climate system with an effective multiplicative feedback factor of 3 which multiplies the applied 11 C forcing to generate the total 33 C terrestrial greenhouse effect.

An early discussion of radiative forcing and climate sensitivity is given by Hansen et al. 1984 (Climate sensitivity: Analysis of feedback mechanisms. Geophysical Monograph 29, Maurice Ewing Vol 5, AGU, 130-163). This paper compares the radiative forcings due to doubled CO2 and to a 2% increase in solar irradiance, and provides a quantitative analysis of feedback contributions due to water vapor, cloud, lapse rate, and surface albedo changes. The paper shows that while feedback efficiencies of the different feedback processes can be compared linearly, the feedbacks combine in a non-linear fashion. In the Hansen et al. 1984 paper, the radiative forcing due to doubled CO2 was 1.2-1.3 C, with the overall feedback factor in the 3-4 range to produce a 4 C global equilibrium warming. More recent results (Hansen et al. 2005, Earth's energy imbalance: Confirmation and implications. Science 308, 1431-1435) suggest that the total global feedback effect is in the 2.1-2.3 range giving a 2.7 C global warming for doubled CO2.

Because of overlapping absorption and saturation effects, the greenhouse contributions of individual contributors depend on their atmospheric context. For example, the radiative forcing due to doubled CO2 in the current atmospheric context is about 1.2-1.3 C (with no feedbacks operating). But removal of the current CO2 amount produces a cooling of more than -7 C (with no feedbacks operating). Analytic formulas that describe the amount of radiative forcing due to different concentrations of atmospheric CO2, CH4, N2O, and CFCs can be found in Hansen et al. 1988 (Global climate changes as forecast by GISS three-dimensional model. JGR 93, 9341-9364). Again, the (applied) radiative forcing is provided by changes in the non-volatile GHGs, aerosols, or solar irradiance. Water vapor, clouds, and snow-ice albedo change in response to the applied radiative forcing and account for the overall global feedback factor which acts to magnify the applied forcing to produce the eventual equilibrium change in global surface temperature

70.134.105.203 03:43, 8 June 2006 (UTC)-- This is great! This has cleared up a lot of the global warming issue for me. Any charts for water vapor concentrations for the globe similar to the charts for the other gases? --70.134.105.203 03:43, 8 June 2006 (UTC)

The MOPPIT Sattilite Images

Do these Sattilite images dipict the difference between the seasons, or the increase over a six month period?

E-Mail me an answer at:

donald_johnston@sympatico.ca

Click Me!

Heteronuclear diatomics

The article points out, correctly, that homonuclear diatomic don't absorb in the IR. It doesn't point out that heteronuclear diatomics such as CO or HCl absorb IR. Should it? I don't think they are very important GHG's. William M. Connolley 16:04, 9 March 2006 (UTC)

The logic flow is: O2 and N2 are major atmospheric components (more than 99% of the total), O2 and N2 are homonuclear diatomics, homonuclear diatomics don't absorb in the infrared, therefore O2 and N2, while by far the most significant of the gases in the atmosphere, have no role in greenhouse gas warming. This is mostly in the form of an explanation for why the most abundant atmospheric gases don't contribute to the greenhouse effect. Were CO and HCl to become more prevalent they'd matter more, but they are more reactive than CO2 so even then they'd disappear faster if they weren't being constantly added to the atmosphere. Minasbeede 03:05, 23 April 2007 (UTC)

Not GA yet

This page was nominated on Wikipedia:Good articles/Nominations, but I have not added it to the list, because although the article is generally very good, the intro needs work - it's extremely confusing to quote lots of percentages and then say you can't really quote percentages anyway. Worldtraveller 00:06, 12 March 2006 (UTC)

percentage of greenhouse effect

The major natural greenhouse gases are water vapor and clouds, which causes about 36-95% of the greenhouse effect on Earth (depending on who you ask); carbon dioxide, which causes between 3.6% and 26% (again, depending on who you ask); and ozone, which causes 0-7% (again, depending on the math)(note that it is not really possible to assert that such-and-such a gas causes a certain percentage of the greenhouse effect, because the influences of the various gases are not additive. The higher ends of the ranges quoted are for the gas alone; the lower end, for the gas counting overlaps).

Obviously this needs help. "Depending on who you ask" is not appropriate for an encyclopedia. How one ascribes the greenhouse affect to various gases (and even whether that question makes sense) is going to depend on how one defines the question. We need to either formulate the range of meanings in way that explains where they are coming from and what they mean to the reader or remove them entirely. Dragons flight 20:47, 2 June 2006 (UTC)

Ah, sorry, I reverted that edit as silly before reading your more thoughtful reply William M. Connolley 21:12, 2 June 2006 (UTC)

Actually, the reverted version still has ranges that are not well explained in the text. We need to think about what the reader wants to know when he asks "How important is X to the greenhouse effect?". Dragons flight 21:21, 2 June 2006 (UTC)

Some of the numbers are sourced on greenhouse effect (which has just suffered another of the periodic additions of the 95% nonsense). Sourcing the numbers properly would be good. Answering your question depends a lot on the context; in terms of real life, people asking that question will tend to mean, "is it true wot these people having been telling me, that WV is a more important GHG than CO2"? in which case they need to find the answer, No. William M. Connolley 21:46, 2 June 2006 (UTC)

"No"? I think the answer needs to be more along the lines of "Yes, but..." myself. Dragons flight 21:59, 2 June 2006 (UTC)

Thats where the context comes in. Scientifically, the answer is yes, if by "important" you mean "causes more of the GHE". But in context, important always elides into in-the-human-context, so the answer is No, but... William M. Connolley 22:13, 2 June 2006 (UTC)

70.134.105.203 03:49, 8 June 2006 (UTC)-- As a layperson the large ranges confuse me more than clarify. Unless something more meaning full can be said, the ranges should probably just be removed from the article. The first question that arises when seeing ranges like that is how any useful climate model could be made. I didn’t see anything in the climate model articles that cleared this up. 70.134.105.203

Ah, then you have misunderstood. The ranges are not a problem for the GCMs at all. The ranges essentially come as *output* from the models, not input William M. Connolley 08:52, 8 June 2006 (UTC)

70.134.105.203This would be an excellent clarification to the article, something like “According to climate models the major natural greenhouse gases are water vapor, which causes about 36-70% … “

I was unable to find these numbers on [Global climate model] , [climate model] so I suppose this is the place for the discussion. As I read the article, greenhouse gases were know to absorb (IR) energy from the sun even before climate models, however climate models demonstrate that the cumulative interplay of the anthropogenic increase in these gases do indeed cause an overall increase in global mean temperature. However, as the ranges demonstrate the climate models don’t provide a certainty on the magnitude of the increase. Have I misunderstood? 70.134.105.203 22:52, 8 June 2006 (UTC)

‘water vapor can not be controlled by humans’ ?

I was under the impression that for every molecule of CO2 produced combusting petroleum products, a molecule of H2O is produced, however that no H2O is produced combusting coal. I was also under the impression that petroleum products accounted for about only 25% of combustion derived CO2 and coal most of the rest, however the chart seems to suggest otherwise. May be the chemical formulas would be helpful to the article.

Does Michael Mann mean to say that water vapor can not significantly be controlled by humans? If so, does not that make the “Thus water vapor acts as a positive feedback (but not a runaway feedback) to the forcing provided by human-released greenhouse gases such as CO2.” discussion insignificant also?

The point you are missing is that excess H2O precipitates rapidly. Co2 doesn't William M. Connolley 17:19, 5 June 2006 (UTC)

‘ misleading to cite the role of water vapor as a greenhouse gas ’ ?

In the section about the role of water vapor, I can read:

"It is extremely misleading, however, when scientists cite the role of water vapor as a greenhouse gas," because it can not be controlled by humans

This statement is itself misleading because it intend to change the definition of Greenhouse gas itself. The definition is given at the top of the article and it seems quite clear and unambiguous.

I am worried that such statement is driven more by a political than a scientific agenda. Maybe that some people are interested to diminish the fact that water vapor is the main greenhouse gas.

Equally, a full paragraph is dedicated to the positive feedback between CO2 and water vapor but the fact that Changes in water vapor may also have indirect effects via cloud formation. is rapidly cited without giving us the consequences of an increase of cloud formation. Nageno 10:54, 19 April 2007 (UTC)

You do indeed seem to be more interested in the politics. There are two things that people might be interested in: how large are various greenhouse gases; and what / which gases are driving recent climate change? For the most people, the second question is more interesting, and citing the large amount of WV in this context *is* indeed misleading, which is why people keep doing it William M. Connolley 11:30, 19 April 2007 (UTC)

Thanks a lot for your reply. I do understand that event if WV represents 2% of the atmosphere and CO2 0,0365% does not mean that the effect of WV on the greenhouse effect is 54 times higher. The article clearly states this fact and we can also find information about it in the Greenhouse effect article. To come back to the citation above, I still think it is misleading and should be removed from the article because the definition of a greenhouse gas does not depend on its human origin.

I would also be glad to find more information about the effect of cloud.

If we were only listening to politic, earth would still be flat. Nageno 22:57, 19 April 2007 (UTC)

I recommned listening to scientists not politicians. As to misleading... I repeat my earlier William M. Connolley 09:38, 20 April 2007 (UTC)

The article starts with this definition: Greenhouse gases are components of the atmosphere that contribute to the Greenhouse effect. Then in the section about water vapor we read "It is extremely misleading, however, when scientists cite the role of water vapor as a greenhouse gas," because it can not be controlled by humans. So either we change the definition at the top of the article or we remove the citation. Nageno 10:50, 24 April 2007 (UTC)

I agree, it does seem to be misleading. Water vapor is barely mentioned outside of this paragraph, while it is a key greenhouse gas.--74.229.48.186 16:20, 22 April 2007 (UTC)

CO2 accumulates. CO2 is in the atmosphere at a temperature far above its boiling (sublimation, actually) point. It accumulates. H2O is, usually, in the atmosphere below its boiling point. There are "relative humidity" tables for H2O but there are no "relative carbonic acid (or whatever they'd be called) tables for CO2 because the CO2 isn't going to precipitate out.

Water vapor isn't ignored. The excess carbon dioxide from the burning fossil fuels alters the makeup of the atmosphere. The H2O vapor from combustion very quickly precipitates out as rain, snow, sleet, etc.

H2O is the major greenhouse gas. The global warming problem is a problem that arises from an increase in the average temperature of the earth because of a man-made greenhouse gas. Without the water vapor the earth doubtless would be much cooler, but the issue is not the average temperature of the earth (to which water vapor makes a substantial contribution), the issue is the change in temperature (from CO2.) Get a bunch of some other greenhouse gas into the atmosphere and that other greenhouse gas will be a major contributor to the problem: no claim is made that CO2 is inherently special. Currently the major problem is identified as the annual increase in CO2 because of the huge amounts of fossil fuels (coal, natural gas, petroleum) burned each year (with the amount burned each year increasing.) It's sort of like a budget. Take a balanced budget (with house payments, taxes, insurance, food etc.) exactly matching income and all is fine. Add a $6/day tobacco habit and the budget goes out of balance. The house payment is much larger than the amount spent on tobacco but the tobacco expenditure is the problem. Minasbeede 03:20, 23 April 2007 (UTC)

Really, this article is about greenhouse gas and not global warming. Greenhouse gas is linked to greenhouse effect (see the definition at the top of the article). So, it would be good to find more explanation about the greenhouse effects due to H2O in its different forms (clouds for example). Nageno 10:50, 24 April 2007 (UTC)

Misleading to cite watervapour as greenhouse gas because it can not be controlled by humans? That statement does not belong here. this is an article about greenhouse gases, perhaps that statement should be in the global warming article, or the article about the man-made global warming effect, but most definitely not here. I'm removing it....I can see no possible argument for it being here. Restepc 03:40, 2 June 2007 (UTC)

Greenhouses

I am intrigued by the assertion that the mechanism for greenhouse gas warming is not the one which warms greenhouses.

My understanding of greenhouses is that the glass lets in visible light from the sun. This is then absorbed inside the greenhouse by the contents, which warm up. The contents then emit infra red light - but this is not transmitted back through the glass, which is opaque to IR light, trapping the energy inside the greenhouse and keeping it warm. This is analagous to greenhouse gases - visible light goes in, gets absorbed by the surface and re-emited as IR - but some frequencies of IR are not transmitted back out because they are absorbed by the greenhouse gases and radiated in all directions. Stephen B Streater 18:29, 28 June 2006 (UTC)

Read the greenhouse effect page (and the extensive talk page discussion, poss the archives) William M. Connolley 19:10, 28 June 2006 (UTC)

Thanks. I've added a wikilink in to help the next guy. Stephen B Streater 21:37, 28 June 2006 (UTC)

General cleanup

I've made a number of edits to remove redundant bits of text, clean up some grammatical slips and so on.

I've also changed the description of the greenhouse effect at the top of the page to one that is more accurate scientifically, though maybe too intricate for a general audience. Since this article is about GHGs as such and not the greenhouse effect, I'm sort of inclined to remove this bit altogether and just have a pointer to the main GE article. Raymond Arritt 04:34, 13 August 2006 (UTC)

Hi! I had a part in writing this bit. The most significant thing for me was the discovery outlined in the last sentence: The term is something of a misnomer, as this process is not the primary mechanism that warms greenhouses., so I'd be keener to keep this last sentence than the rest which is, as you point out, explained in its own article; a wikilink could suffice here. Stephen B Streater 17:18, 13 August 2006 (UTC)

Units for radiative forcing

Hi, I'm a bit confused by W/m² as units for radiative forcing - surely there should be a ppm component to this thing as well? Or some such? Clarification is not to be found in radiative forcing, either. Graft 19:13, 24 October 2006 (UTC)

No... the rad forcing is... well, the 1.46 W/m2 for CO2 is for the 87ppm increase over preindustrial. You could perhaps express it as 1.46/87 W/m2/ppm but it wouldn't be that accurate William M. Connolley 19:46, 24 October 2006 (UTC)

Ah. So, there's an observed forcing for the increase that has actually transpired, 1.46 w/m^2 - but is there some theoretical number, here, i.e., the general potential forcing of CO2? Cuz this is how I read that table. To me it says: given equal quantities of CO2 and methane, methane results in far less forcing than CO2 does. But this is probably not what it's saying. It's actually apportioning the amount of observed forcing attributable to various greenhouse gases. Right? So where does one find the former quantities? Graft 19:50, 2 November 2006 (UTC)

1.46 is calculated, not observed. And no, the methane forcing is smaller, but thats in total - per molecule, methane is stronger. Sorry - I though all this was obvious William M. Connolley 20:40, 2 November 2006 (UTC)

Calculated, observed, same difference - my point is, why don't we have a table of per-molecule forcing? Surely this is relevant? As to it being obvious, maybe it should be, but it could clearly be made more so. Graft 16:56, 3 November 2006 (UTC)

To be fair, since the effects are not linear (in fact logarithmic in many cases) and different gases interfere with each other through overlapping absorption bands, it isn't a trivial matter to construct such a table. Really, such a comparison is most sensibly limited to discussing the forcing associated with small changes in gases relative to the modern atmosphere. Dragons flight 23:06, 3 November 2006 (UTC)

The Expert syndrome: Knowing so much that no one else can understand a word you say. Though if there is a good table on the differential impact of various greenhouse gases relative to the modern atmosphere, I'd love to see it. For some reason, climatologists don't seem to think about greenhouse gases in the same way as physicists. Dragons flight 21:07, 2 November 2006 (UTC)

Emissions by Country

The article is quite graph-heavy already, but can anyone find an appropriate place to add this graph (from the Pollution article)?

Historical and projected CO2 emissions by country (1990-2025).
Source: Energy Information Administration.

There seems to be very little in this article (or elsewhere on Wikipedia, unless I've missed it) regarding the differing levels of greenhouse gas emissions between countries, or the differences in growth rates. -84.68.87.155 23:42, 27 October 2006 (UTC)

Go to http://www.eia.doe.gov/emeu/iea/carbon.html for a heap of countries and annual rates of emission.

Hey! How come the countries of Australia and New Zealand got lumped together in the plot?

Australia is downwind of New Zealand's sheep. Kd4ttc 21:47, 8 March 2007 (UTC)

Classroom science experiment?

Can the page suggest or link to a classroom science experiment to test the insulating properties of greenhouse gasses? For example, is there a simple test where the rate of cooling of a beaker of hot water can be measured in a standard atmosphere and then in a carbon dioxide enriched atmosphere? — Preceding unsigned comment added by 128.250.6.243 (talk • contribs) 08:21, 5 November 2006 (UTC)

Hmm... How 'bout two bell jars, two beakers of hot water, two thermometers, a source of CO2 and test. Maybe add manometers and a means of equillizing the pressure of the two bell jars as CO2 is added to one and ... then publish your findings and report back here :-)

Vsmith 14:50, 5 November 2006 (UTC)

Given that the infrared optical depth in the atmosphere is is not huge, I fear you'd need a quite high concentration of CO2 to get a measurable effect on laboratory scales (at least with classroom level equipment). Dragons flight 09:42, 6 November 2006 (UTC)

With appropriate simplifying assumptions, can a basic model be posed to predict the rate of cooling in the two scenarios?

Would a visualisation be possible? Perhaps an infrared camera could be used to observe a bar heater through a partitioned tank that has a standard atmosphere on one side and CO2 on the other.

Right, now to find some scientists that can help out! Would any science teacher and their class of budding scientists be interested in testing the hypothesis that CO2 acts as a greenhouse gas?

repeat the original experiment?

Find the reference to the 1890 experiment. They put a glass tube between a light source (I think they used a mirror reflecting sunlight) and then filled the tube with different gases and measured the temperature.

As a science fair project perhaps two plots of earth (maybe 3 foot by 3 foot) could be covered with a foot-thick frame covered with thin plastic (such as used for dry-cleaner bags), well sealed. One frame could simply contain air, the other carbon dioxide. Leave the frames off during the day and then put the frames over the plots. Measure the temperature periodically. On different nights alternate the frames with the air and the CO2. Tabulate the results.

In other words, the frames are transparent top and bottom. The thin plastic will also absorb infrared radiation but if the frames are identical the difference will be due to the difference between air and CO2.

This isn't a full, perfect CO2 global warming experiment but it's something that can help create understanding. —The preceding unsigned comment was added by Minasbeede (talk • contribs) 16:44, 16 March 2007 (UTC).

Greenhouse Gases - human factor

please go away and read Chapter 3 of IPCC TAR and then come back if you still have any questions.--NHSavage 21:59, 7 November 2006 (UTC)

Just so you know water vapor is just that H2O atomized, it is NOT A GAS! It is Humidity in the atmosphere and NOAA measures it as WATER, not a gas!

However, water vapor still remains the number one contributer to the greenhouse effect. http://www.ncdc.noaa.gov/oa/climate/gases.html#wv

Observational Database

A large observational database of many different atmospheric constituents including greenhouse gases from a host of platforms is available. This was created as part of ESA Envisat and NASA Aura validation. It is of general use. Do you think it should be added to the article text? Dlary 03:16, 4 February 2007 (UTC)

CO2 is a greenhouse gas

It is widely understood that carbon dioxide acts as a greenhouse gas. Out of interest, is there a suitable reference to some fundamental report or study? Chrisnumbers2000 05:48, 7 February 2007 (UTC)

The Arrhenius article is pretty good. Raymond Arritt 05:53, 7 February 2007 (UTC)

The only actual experiment I've found proved that CO2 is a greenhouse gas ONLY if atmospheric pressure increases as well. It was conducted in the 1890's I think, but I haven't been able to relocate it in google. If it really is true that no institution has ever repeated this experiment in such a long time, that makes me... somewhat disappointed in modern science if we can have such a large debate over global warming and CO2 and then nobody has ever ponied up an actual experiment as proof in over a 100 years. How has global atmospheric pressure changed in the past 100 years? Has it increased? Decreased? Stayed the same? 64.126.164.3 04:14, 14 February 2007 (UTC)

Your premise is mistaken. Perhaps you're confusing the partial pressure of CO2 with total atmospheric pressure. Raymond Arritt 04:42, 14 February 2007 (UTC)

I dont remember the specifics because I'm unable to reproduce the search term that brought me to the page with the experiment mentioned. Basically what I remember is that you could have x amount of CO2, and it's ability to be a green house gas increased with y, where y is the total gas stuffed into a container.64.126.164.3 23:43, 14 February 2007 (UTC)

Contrarian references

Please, gentlemen, acknowledge that this is a controversial topic, with well-respected climatologists having very different opinions. Please do not make it an editorial for one POV by deleting references to minority viewpoints. NCdave 17:45, 15 March 2007 (UTC)

BTW, contrarians are by no means nuts. They include some prominent scientists, such as Alabama State Climatologist John Christy, Oregon State Climatologist George Taylor, Colorado State Climatologist William Gray, and many others. NCdave 18:31, 15 March 2007 (UTC)

Fossil Fuel Burning cannot exceed Total Flux, All Sources

This is shown in the top diagram part 2 Carbon Flux. Can somebody fix this? --Nick Green 03:38, 18 March 2007 (UTC)

The lines are correct, but it would be clearer if the legend were labeled as "all sources and sinks". I'll ping Robert and see if he can fix it. Raymond Arritt 03:48, 18 March 2007 (UTC)

Thanks Raymond. Is there any good empirical data on sinks yet?--Nick Green 03:02, 19 March 2007 (UTC)

The TAR chapter is as good a starting point as any though it's a little old by now. The whole carbon sink/sequestration/storage area is moving very fast, both in terms of observations as well as proposals for methods to increase carbon uptake. Raymond Arritt 03:16, 19 March 2007 (UTC)

Thanks again Raymond. Yes the Branson prize might help but we really need to use a mass produced instrumentation approach- we know so little about microbial biomass, for example, and its products- an eGaia Project? Still this is not the place to speculate--Nick Green 14:42, 23 March 2007 (UTC)

New additions to the "Increase of greenhouse gasses" section

This was recently added to the section without any discussion or explanation: Another theory on the cause of CO2 level increases, among other green house gases, is that their increase lags global warming. CO2 levels increase as the global temperature increases. This is partly due to ocean warming. When the ocean warms, it releases CO2. When the ocean cools, it absorbs CO2. When looking at ice core samples from a much broader perspective, we see that CO2 levels increased after the earth began to warm up. Also, in Bruno Wiskel's book "The Emperor's New Climate" (2006), on page 110-112, we see more factors on the release of CO2, among other greenhouse gases, into the atmosphere. Wetlands for instance are the largest producers of methane. As the wetlands warm up, along with the global temperature, their ability to produce methane increases. Some other factors mentioned in Wiskel's book are the release of CO2 from the soil under glaciers, when they melt. As a result, the theory that industrialization has caused global warming could be entirely false.

First, Bruno Wiskel doesn't have an article and the book isn't that well known. A search on Google for "Bruno Wiskel The Emperor's New Climate" returns 11 hits. This section seems very dubious. I'm not saying it is false, but I've never heard anything like this and the person and book cited don't seem that notable. Unless more appropriate citations can be added, I think this section needs to be removed. Ungovernable Force^{Poll: Which religious text should I read?} 05:23, 7 May 2007 (UTC)

I've removed the new section. Since there is zero scientific support for this new idea (at least for the present day) I don't think it belongs William M. Connolley 10:32, 7 May 2007 (UTC)

I don't blame you one bit. Ungovernable Force^{Poll: Which religious text should I read?} 10:38, 7 May 2007 (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.

(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)

The role of water vapor

Why does "The role of water vapor" section keep getting removed by various people? It's very annoying to have to revert edit after edit. Maybe we need to discuss why you don't believe the fact that water vapor is a greenhouse gas.Invasion10 08:56, 17 May 2007 (UTC)

Yes, water vapor is a greenhouse gas

It is necessary to understand the situation and the discussion. When man-made global warming is discussed the topic is, specifically, a change in the average temperature of the earth brought about by the actions of man. That's a change in temperature from what the temperature would be absent the additional greenhouse gas.

Water vapor is the most significant greenhouse gas but water vapor rapidly leaves the atmosphere (snow, rain, hail.) Add a million tons of water vapor to the atmosphere and there very quickly will be a million tons of additional precipitation. Add a million tons of CO2 to the atmosphere and that CO2 will persist for decades, slowly being removed by natural processes. (This isn't a quantitative statement: I don't claim that combustion of fossil fuels, in total, produces equal masses of H2O and CO2. "Million tons" is a phrase used to indicate "a lot.")

Something that also gets too little attention is that a one degree (Celsius) increase in the average temperature of the earth is only a little more than a 0.3% change in temperature. That one degree change can have significant global effects but it's still just a little more than a 0.3% change. It is entirely possible that man's activities can cause a change of that magnitude.

It is false logic to conclude that since water vapor is the most significant greenhouse gas that the effect of added CO2 can be ignored. The global warming issue is not the temperature, it's the change in temperature. The effect of the water vapor appears in the temperature. The added CO2 contributes to an increase in temperature.

Minasbeede 16:30, 18 May 2007 (UTC)

(I removed my intemperate statements about content in article that appeared to be neither factual nor NPOV in nature. What I wrote was also not NPOV.)

Minasbeede 15:27, 1 June 2007 (UTC)

This was added by anon 217.42.21.7 and is now deleted. It's totally wrong, of course, but that doesn't stop it being used as a common skeptic talking point. (Tim Ball even claims that water vapor is left out of the models... sigh.) Raymond Arritt 14:42, 1 June 2007 (UTC)

Would you have a quote for that? We then could address the point head on in the article. — Sebastian 14:45, 1 June 2007 (UTC)

The recent Soden and Held (2006) article diagnoses cloud feedbacks in GCMs (it would be tough to diagnose something that doesn't exist). There's a nice figure that shows magnitudes of the various feedbacks. Or were you thinking of a quote from one of the IPCC reports or another source that says something very direct, along the lines of "All modern general circulation models contain parameterizations for radiative transfer, clouds..."? Raymond Arritt 15:06, 1 June 2007 (UTC)

It doesn't have to be all; the claim that "cloud formation [is] largely ignored in climate models" is easily refuted by a statement like "modern general circulation models, such as ..., model cloud formation". Would you have a link or two that we could use as a reference? — Sebastian 18:25, 1 June 2007 (UTC)

Maybe something like this excerpt from chapter 8 of the WGI report of the AR4: "Cloud parametrizations are based on physical theories that aim to describe the statistics of the cloud field (e.g., the fractional cloudiness or the area-averaged precipitation rate) without describing the individual cloud elements. In an increasing number of climate models, microphysical parametrizations that represent such processes as cloud particle and raindrop formation are used to predict the distributions of liquid and ice clouds. These parametrizations improve the simulation of the present climate, and affect climate sensitivity (Iacobellis et al., 2003)." (reference here; specifically at subsection 8.2.1.3.) I'd still like to find something that explicitly says "all modern GCMs include the effects of clouds", but it's such an obvious point that maybe no one has bothered stating it. Raymond Arritt 19:06, 1 June 2007 (UTC)

(addendum) Maybe "current state-of-the-art climate models include fully interactive clouds" from this source? Raymond Arritt 19:12, 1 June 2007 (UTC)

That's perfect! I'll add that. — Sebastian 22:13, 1 June 2007 (UTC)nooooooooooooooooooooo

Actually, that belongs rather in the article Climate model. I'll write something on its talk page, please follow the discussion there. — Sebastian 22:22, 1 June 2007 (UTC)

Logarithmic relationship between CO2 levels and absorption.

No discussion on greenhouse gas, CO2, water vapor, or otherwise, can be considered accurate or complete without an explanation of Beer's Law as it applies to the absorption of radiation by these gasses. It is not a direct relationship such as "the more gas, the more absorption." It's logarithmic. Each additional increase has less and less effect until you reach saturation. CO2 is already nearing that saturation point, and therefore more of it in the atmoshphere has little effect. You would have to add roughly 10 times as much as current levels over the next 100 years to have the same effect as the last 100, and this is total CO2, not just human emissions. Additionally, the arguement that water vapor "doesn't count" becasue of its short lifespan in the atmosphere is bunk as this only applies to the lifespan of a particular molecule of water vapor. The water cycle is continuous, therefore the overall levels of water vapor, for all intents and purposes, remain the same. As one molecule condenses back into liquid water, another is evaporating and entering the atmosphere. [this unsigned comment was added on 23 May 2007 by 63.237.28.10]
(Don't forget to sign.)

In other words, adding more CO2 to the atmosphere is much like adding another layer of paint to an already almost-opaque surface. It doesn't reduce the amount of transmitted light by very much at the wavelengths that it blocks, because those wavelengths are already mostly blocked anyhow.

The second illustration in the article ("Radiation Transmitted by the Atmosphere") illustrates 63.237.28.10's point pretty well, if you study it: most of the wavelengths blocked by CO2 are already almost 100% blocked.

You are right, 63.237.28.10. This article definitely needs a discussion of Beer's Law. NCdave (talk) 01:52, 16 March 2008 (UTC)

The paint analogy is not useful, for many reasons (not the least of which is that it concerns visible wavelengths rather than thermal IR). The bit about saturation of wavelength bands is a widely-held misconception; see Spencer Weart's review for an excellent educated-layman level discussion.[2] The key sentence there is "The greenhouse effect will in fact operate even if the absorption of radiation were totally saturated in the lower atmosphere." Please read the rest of Weart's article for the full explanation. Raymond Arritt (talk) 02:39, 16 March 2008 (UTC)

Thank you for the interesting link, Raymond. The author is arguing that it matters not only how much of the radiation is absorbed, but at what altitude it is absorbed. He contends that it is the upper atmosphere which matters the most:

"The greenhouse effect will in fact operate even if the absorption of radiation were totally saturated in the lower atmosphere. The planet's temperature is regulated by the thin upper layers where radiation does escape easily into space. Adding more greenhouse gas there will change the balance..."

But that is not describing the greenhouse effect! The greenhouse effect is the blockage of IR radiation from the surface of the earth. The more thoroughly that radiation is blocked in the lower atmosphere, the less of it reaches the upper atmosphere. NCdave (talk) 07:25, 19 March 2008 (UTC)

No, the greenhouse effect is derived from the total ability of the atmosphere to capture and recycle thermal radiation. It is not just the Earth's surface that emits IR. The atmosphere also emits thermal radiation. IR from the lower atmosphere can be captured by greenhouse gases in the upper atmosphere, etc. High levels of greenhouse gases in the lower atmosphere capture IR radiation from the surface and warm the lower atmosphere. In turn the warmed lower atmosphere will emit more IR. Depending on circumstances, this can even lead to more IR radiation reaching the upper atmosphere than if no greenhouse gases were present at all. The logarithmic relationship is largely a consequence of the fact that the atmosphere is not only an absorber but also an emitter of infrared radiation. Dragons flight (talk) 07:48, 19 March 2008 (UTC)

A Response

It's one thing to claim that CO2 is nearing the saturation point and another thing to show it. You've claimed it but have shown no reference to back the claim. Show the data, please, if it exists. Surely the absorption coefficients of CO2 are well enough known that this should be a simple matter.

It's rather unlikely that of all the scientists who warn of the greenhouse gas crisis none are aware of Beer's law. In particular those scientists who do modeling of the effect of an increase in atmospheric CO2 are overwhelmingly likely to do the computations according to Beer's law and not according to a linear mode. Still, over any small range, doesn't a logarithmic curve look approximately linear?

Your explanation of the reason water vapor is not considered a greenhouse gas of concern is far better than one that talks of a short lifespan, although these are or should be different ways of expressing the same thing. the "short lifespan" statement about water vapor implies a comparison with CO2, which has a longer lifespan since there is no mechanism similar to precipitation that quickly removes CO2 from the atmosphere. There, again, it isn't individual molecules that matter (and molecules of water are indistinguishable one from another), it's the total concentration. Burning of fossil fuels is another source of atmospheric CO2. Absent the burning of the fossil fuels there would be more or less of a balance among atmospheric carbon (as CO2), biological carbon, and carbon in dissolved CO2 in the oceans and lakes. The CO2 concentration measurements taken in Hawaii would show the same seasonal variations but would lack the constant upward motion attributed to the increase in atmospheric CO2 from burning fossil fuels.

Minasbeede 03:41, 24 May 2007 (UTC)

FOUR MAJOR QUESTIONS 1)As the temperature of the Atmosphere increases do the oceans absorb some of the heat; water is a very good heat sink, and doesn’t the increasing ocean temperature cause increased evaporation and reduce the oceans ability to trap CO2? 2)How exactly do 308 molecules out of 1,000,000 get warm enough to heat the total number of molecules, there doesn’t seem to be enough mass. Say that CO2 was 1,000 times hotter than the other gasses do to i ts “greenhouse-ness” there would be no thermometer detectable increase in the total temp… maybe a thousandth of a degree? 3)And aren’t the Oceans a huge, HUGE (huge is not adequate to describe the relative size of the Oceans vis-à-vis the Atmosphere) , heat sink removing heat from the atmosphere? 4)So exactly how are the additional 100 parts-per-million of CO2 molecules over 100 years going to increase the temperature of the Earth? Might not the Sun be the cause of the global warming? Might the warming be the cause of the additional CO2 as follows; Warming surface of the Earth releases CO2 from the soil, warming oceans release CO2 from their stores? mefcrf:Mefcrf 07:53, 2 June 2007 (UTC)

A1: Increased water vapor and lessened ability to trap CO₂ are both positive feedback mechanisms for warming. With global warming everything can get warmer, including the oceans.

A2: The issue is energy. Absent the extra CO₂ more of the daily amount of solar energy absorbed by the earth would escape directly to outer space. If more energy is absorbed in the atmosphere the net result is a slowing of the escape of that daily dose. All the energy that the earth absorbs from the sun eventually re-radiates. Most re-radiates the same day. Some of the energy absorbed by the atmospheric CO₂ will re-radiate at the same frequency as the radiation that was absorbed, some will get transferred to other molecules by collisions. The details may be complex. The essential consideration is that energy is conserved. If the energy doesn't make it to outer space in a single step then its escape to outer space is slowed, by definition.

A3: Same as above. If the oceans absorb energy they get warmer. That, too, is part of global warming.

A4: By slowing the escape of solar energy to outer space. Most of the solar energy absorbed each day is radiated into outer space as infrared radiation. The added CO2 in the atmosphere causes a small part of the radiation from the surface to be absorbed in the atmosphere. (Consider other infrared radiation for which there is no atmospheric absorption. It escapes earth in a single shot.) The sun is what makes the earth habitable. The sun is the reason the earth isn't at 4^o Kelvin. If the sun puts out more energy per unit time the earth will be warmed by that. No credible spokesperson claims that the earth's temperature has always been constant and would remain so absent global warming. Added release of CO₂ due to warming is a positive feedback mechanism. Dead plant material rots. IF it's warmer the rotting process is likely to be faster, causing the amount of CO₂ returning to the atmosphere to go up: positive feedback.

A 1° change in the average temperature of the earth is under a 0.4% change in the average temperature of the earth. While that is a small change it has major effects. Those major effects are the reason for the concern. Absent the major effects global warming would be "no big deal."

Minasbeede 15:25, 2 June 2007 (UTC)

One More Time: Exactly how does a 100 parts per million over 100 years cause the kind of warming observed? What model shows this? 68.101.111.61 07:41, 3 June 2007 (UTC)mefcrf

You've been given he answer, even if you haven't understood it. The answer is basic radiative physics plus some feedbacks, or perhaps HadCM3 William M. Connolley 09:22, 3 June 2007 (UTC)

Please see radiative forcing. James S. 15:11, 5 June 2007 (UTC)

Emissions

I see no claim made that all emissions due to burning of fossil fuel remain entirely in the atmosphere. Either the vehicular emissions did or did not grow as was claimed in the removed material. The level of emissions of greenhouse gases from the combustion of fossil fuel is pertinent, is it not? That the growth in atmospheric CO₂ is less than the total emissions over a period of time does not disprove the level of emissions nor reveal the data to be incorrect.

Minasbeede 14:09, 5 June 2007 (UTC)

source of graph

What is the source of the graph "green house gas emissions by source"? Northern Bear 16:36, 5 June 2007 (UTC)

According to [3]:

This figure shows the relative fraction of man-made greenhouse gases coming from each of eight categories of sources, as estimated by the Emission Database for Global Atmospheric Research version 3.2, fast track 2000 project. These values are intended to provide a snapshot of global annual greenhouse gas emissions in the year 2000.

--Kim D. Petersen 17:18, 5 June 2007 (UTC)

Repeated deletions of National Academy of Sciences findings

William M. Connolley has repeatedly[4][5][6] deleted the following section, sourced to a peer-reviewed National Academies of Sciences report:

Underestimation by IPCC

The Intergovernmental Panel on Climate Change (IPCC) underestimated 2000-04 CO₂ emissions by a substantial amount. CO₂ emissions from cars, factories, and power plants grew at an annual rate of 1.1% during the 1990s, but from 2000 to 2004, CO₂ emissions growth rates almost tripled to 3% per year.

Raupach, M.R. et al. (2007) "Global and regional drivers of accelerating CO2 emissions" Proceedings of the National Academy of Sciences

The reasons given in summaries were:

• "rv: as per GW page: releveance is dubious AND atmos CO2 only grew at 2-3/y ppmv in 2000-4"
• "rm - remains of no clear importance - needs to discuss short timeframe & actual CO2 concs)"
• "its not criticism; other reasons as before"

The abstract of the source reads:

"CO2 emissions from fossil-fuel burning and industrial processes have been accelerating at a global scale, with their growth rate increasing from 1.1% y�1 for 1990–1999 to >3% y�1 for 2000– 2004. The emissions growth rate since 2000 was greater than for the most fossil-fuel intensive of the Intergovernmental Panel on Climate Change emissions scenarios developed in the late 1990s. Global emissions growth since 2000 was driven by a cessation or reversal of earlier declining trends in the energy intensity of gross domestic product (GDP) (energy/GDP) and the carbon intensity of energy (emissions/energy), coupled with continuing increases in population and per-capita GDP. Nearly constant or slightly increasing trends in the carbon intensity of energy have been recently observed in both developed and developing regions. No region is decarbonizing its energy supply. The growth rate in emissions is strongest in rapidly developing economies, particularly China. Together, the developing and least-developed economies (forming 80% of the world’s population) accounted for 73% of global emissions growth in 2004 but only 41% of global emissions and only 23% of global cumulative emissions since the mid-18th century. The results have implications for global equity." (emphasis added)

Since this is clearly criticism, I believe that WP:NPOV requires the inclusion of this caveat. I would like to know what other people think. --James S. → talk 07:50, 8 June 2007 (UTC)

First, no it isn't criticism. Its just some findings. Second, your reporting of it is badly biased because you are failing to report on the all-important atmospheric concentrations which actually remain within SRES bounds. Which you know because it was discussed on t:GW William M. Connolley 08:54, 8 June 2007 (UTC)

"Findings" that observations are not in line with IPCC projections are most certainly criticism -- what reason do you have to say that they are not? Even if they weren't, they would still be a different, important, and impeccably sourced point of view, and must be included. Atmospheric concentrations aren't the subject of the report, emissions are. Why are concentrations "all-important"? They may be within SRES predictions at the moment, but if emissions continue to rise as much as have been above IPCC predictions, they will not be for long. --James S. → talk 12:45, 8 June 2007 (UTC)

This is hopeless. Why are concs all-important? For the obvious reason: they provide the radiative forcing. Emissions don't. And you still persist with your own bizarre defns; this is not crit. Now, if you want to add something balanced and sensible in the CO2 emissions section, that would be fine William M. Connolley 12:51, 8 June 2007 (UTC)

The CO2 emissions section is under external links, but I added the PNAS and Science quotes anyway. --James S. → talk 05:06, 11 June 2007 (UTC)

What provides the concentrations? The emissions! I'm looking at a half dozen definitions of the word "criticism" and I can't believe you when you say the Raupach paper isn't a "comment expressing fault" or a "critical comment or judgment" or a "serious examination and judgment of something" -- why you would think that it's not all three of those is unclear to me. --James S. → talk 13:11, 8 June 2007 (UTC)

Concs are measured in the atmos. Its clear that they are pretty well on the IPCC proj's - not way above William M. Connolley 13:29, 8 June 2007 (UTC)

Its clear to me that James and I strongly disagree on this. Based on past experience, I doubt we will come to any understanding so I invite others to express their opinions William M. Connolley 13:29, 8 June 2007 (UTC)

I've mv'd and re-written it into what looks like the most appropriate section William M. Connolley 20:41, 11 June 2007 (UTC)

I'm collecting all the findings of the PNAS paper and will add a balanced representation of them shortly. Bendž|Ť 11:53, 16 June 2007 (UTC)

Alright, I've read the discussion on the global warming page, and Connolley, you're violating WP:OR by giving precedence to your own reading of the graph data over the author's interpretations in text of the research paper. I did notice the discrepancy but let's just report what the scientists find, shall we? All sorts of adjustments have to be made to be able to use data from different sources, but if they conclude one thing from the data it's not our place to say that's incorrect when it has been peer reviewed by the United States National Academy of Sciences. Until another paper points out an error, we'll have to settle for the findings in this one. Bendž|Ť 13:46, 16 June 2007 (UTC)

Water vapour

Is the latest deletion another example of censorship on Wiki? Water vapour does indeed condense when air rises and forms clouds. Clouds reflect sunlight and thus cool the earth. In addition, rain fallng from clouds dissolves CO2 very readily, so s another example of negative feedback. Are you questioning the basic science of my additions? It may not be mentioned in your paper (which I find hard to believe), but surely must be added to the current article, which in its current form is highly misleading. Peterlewis 16:54, 11 July 2007 (UTC)

You can check yourself if its in the paper - here is the full version[7] --Kim D. Petersen 18:11, 11 July 2007 (UTC)

The wikitext (and I assume the paper, but I haven't checked) says that relative humidity stays approximately constant. If that's true then the cloud frequency shouldn't change much, which would mean that the negative feedback you suggest isn't occuring even though there is more total water content. Dragons flight 18:32, 11 July 2007 (UTC)

Precisely; cloud frequency doesn't increase from this, which means no increase in albedo (so no cooling there). We're looking at water vapor as a greenhouse gas, not aerosols, not clouds. Maybe it will rain more in a warmer world, but you'll have to back that up. Bendž|Ť 19:15, 11 July 2007 (UTC)

So increased water vapour content doesn't lead to cloud formation? In the real world (as opposed to the model world) this is what happens as you increase water content in the air. As humid air rises it condenses, or don't the models allow for this obvious fact? Most models appear to predct greater ran , which will wash more CO2 from the air. Simple physics. Peterlewis 20:15, 11 July 2007 (UTC)

It takes more water to make a cloud when the air is hotter. The statement about relative humidity is suggesting that the two effects about cancel out. In other words, the increased difficulty in forming clouds due to higher temperatures is about balanced by the fact that there is more water vapor in the air. And yes, the models do cover this. Also, I think you'll find that appeals to "simple physics" won't get you very far in climate discussions where there are many different issues to consider. References to research findings are much better. Dragons flight 20:26, 11 July 2007 (UTC)

It may well be that "more CO2" is washed from the air (simple physics) but the measurements show that the atmospheric CO2 level is increasing. The measurements indicate that approximately half the CO2 released by the combustion of fossil fuels doesn't stay in the atmosphere. Maybe some that doesn't stay is washed out of the atmosphere by rain, including the postulated extra rain. The warming effect is from the roughly half that isn't washed out or otherwise removed.

If there are more clouds and they're going to be used to argue against global warming due to fossil fuel combustion then it would seem necessary to discuss both the daytime and the nighttime effects of clouds. Day and night clouds have a greenhouse effect. During the day they reflect some sunlight (reducing the solar energy reaching the earth) but that's not the sole effect of clouds. Is there a model study anywhere that indicates what the temperature of the earth (or an earth-like planet) would be if it were 100% covered with clouds 100% of the time? Warmer than the actual earth, or cooler? (I can't even guess whether a permanent light cloud cover or a permanent heavy cloud cover would lead to the greatest warming - or greatest cooling.) Minasbeede 21:10, 11 July 2007 (UTC)

You guys are all missing the point that greenhouse gasses increase the temperature BELOW them, not ABOVE them. You can have a higher temperature and higher WV content in the lower atmosphere, but the temperature in the upper atmosphere is not increased to as great a degree, so it does stand to reason that there will be greater frequency of clouds with a warmer lower ATM and a relatively cooler upper ATM. With greater temperature variation in the z-axis, get ready for some good thunderstorms, folks.

Most models suggest that a permanent cloud deck causes a chilling effect at the surface because the heat at the Earth's surface comes from the Sun (at least, it is orders of magnitude greater than the heat that seeps from below the crust). —Preceding unsigned comment added by 68.80.43.122 (talk) 17:01, 14 February 2008 (UTC)

Logarithmic

Re [8]: FWIW the effect *is* logarithmic: but this (of course) doesn't make additions negligible William M. Connolley 21:05, 31 August 2007 (UTC)

Logarithmic behavior has been mentioned several times above already. I think if the "logarithmic behavior" argument is to be used it has to be used in the context of a complete analysis or model and not merely invoked without exposition. I'm not a climate professional so I won't attempt to deal with this issue but I can see how what is claimed or implied by those who bring up "logarithmic behavior" is different from reality. Minasbeede 21:18, 31 August 2007 (UTC)

Agreed. logarithmic => negligible is one of the stupider septic arguments around. But explaining the dependence would be sensible William M. Connolley 21:38, 31 August 2007 (UTC)

It probably would, but I suspect that the way to do it is within the context of a model, and that alone would take a lot of explaining. What I suspect is that the flaw in the logic is the implicit assumption that the radiation either makes a single pass through the atmosphere or is stopped by a greenhouse gas just once. Can't be so. The energy eventually makes its way to outer space (or we'd all be really hot.) As the greenhouse gas levels increase it would take more hops, on the average, for the blocked component of the radiation to escape, with that causing global warming. But I'm not an atmospheric scientist, I can't provide a reference to any work that describes it, so I won't put it into the article. (I've left out repartitioning of the energy within the atmosphere that would have to occur. That's why I think a model is needed.)

To me global warming is the result in an increase in the average time it takes for solar energy received as solar radiation to escape the earth into outer space. That, too, I have no reference for. The point here is that while global warming can be represented as a very slowly increasing "average temperature" it's really something that happens every day. Which is sort of a "duh" statement, because the greenhouse gases that are the source of the man-made warming are in the entire atmosphere (pretty much, close enough) and have an effect 24/7.Minasbeede 22:22, 31 August 2007 (UTC)

I would suggest that the best article for discussing the logarithmic effects would be the Radiative forcing article. Ben Hocking ^{(talk|contribs)} 22:39, 31 August 2007 (UTC)

Origin of Gases

All greenhouse gases occur naturally except for chlorofluorocarbons, so the article should state the truth and not a half-truth. We should not kid the readers.Peterlewis 21:38, 5 September 2007 (UTC)

So we could say "All greenhouse gases occur naturally except for chlorofluorohydrocarbons" - no, that would be misleading William M. Connolley 22:01, 5 September 2007 (UTC)

I see that sentence as just being introductory: some greenhouse gases occur naturally, some are man-made. I don't see any quantitative indication in the sentence nor any need for such an indication. The sentence sets the stage: there are naturally occurring greenhouse gases, there are man-made greenhouse gases. The article then goes on. The greenhouse gas effect has been understood for about 100 years (even if 100 years ago the means for doing quantitative of effects were inferior to those today.) The sentence could be paired negatives: not all greenhouse gases are natural & not all greenhouse gases are man-made. That's cumbersome, and doesn't say any more than saying some occur naturally and some are man-made. --Minasbeede 00:13, 6 September 2007 (UTC)

The sentence implies a false dichotomy: are CO2, CH4, and N2O natural, or are they man-made? The answer of course is "yes", but as written the sentence obscures that. Raymond Arritt 00:19, 6 September 2007 (UTC)

"Yes" they are both - I can't even figure out your point. The sentence does not identify any greenhouse gas and isn't meant, as far as I can tell, to do anything other than to state that greenhouse gases arise both from natural causes and from human activity. Looked at from a WP perspective, it's fully NPOV (it hardly says anything.) It's (as far as I can see) not a sentence that in any way attempts to apportion greenhouse gas effect according to the source of greenhouse gases, it's just saying some are natural, some are man-made. If the article itself as a whole fails to spell out the origins of greenhouse gases then that's where editing may be needed. --Minasbeede 00:33, 6 September 2007 (UTC)

I'm gonna have a stab at changing it, it certainly can't stay as it is, it's extremely misleading. If you want to change what I've written, do so, hopefully eventually we can get something good...but, do not simply change it back to what it is now, it is currently misleading and that can in no way be preferable to whatever I'm about to write. Restepc 13:13, 30 September 2007 (UTC)

Okay, so I guess I can't change it, wiki lags out whenever I click 'save page'. This is what I came up with

Greenhouse gases are components of the atmosphere that contribute to the greenhouse effect. With the exception of Chlorofluorocarbons, the main sources of all greenhouse gases are natural, but human activity also contributes to some, and is the sole source of Chlorofluorocarbons. Greenhous gases include water vapor, carbon dioxide, methane, nitrous oxide, and ozone.

constructive criticism/edits are welcome, I'm aware it's not exactly poetry, I'd be grateful if someone else who has a better relationship with the wiki-server can change it for this, or their own version of this. Restepc 13:37, 30 September 2007 (UTC)

It seems that there's a desire to communicate a message that most of the greenhouse gases are natural and to press that message into being support for an attitude that since most of the gases are natural there's not any real reason for concern (a denier message.) Perhaps both Wikipedia and the world as a whole could do a better job of distinguishing between the average temperature of the earth and the influence of greenhouse gases on that and the change that is occurring in the average temperature of the earth due to the added man-made greenhouse gases. To make that distinction is fully reasonable. It is quite true that the naturally occurring greenhouse gases have a bigger effect on the temperature. The concern isn't over the temperature, it's over the increase in temperature, and that increase can be attributed to the added greenhouse gases, principally from the combustion of fossil fuel. That is, it's reasonable unless deniers try to confuse people about the difference between the temperature and the change in temperature (which, of course, is exactly one of the deceptions they attempt.) It's useful clarification to show most of the greenhouse gas effect comes from naturally occurring gases. Following that, it's useful to show that the added greenhouse gases are adequate to cause an increase in average temperature that is reason for concern, attention, and action. Ideally, the educated citizen will know pretty well what the major influences on the average temperature of the earth are. Then the educated citizen can understand what's being discussed. The educated citizen will need to know that while most of the greenhouse gas effect is due to naturally occurring gases in the atmosphere and has been so from far before there were any significant man-made greenhouse gases the added greenhouse gases due to the activities of man do have a large enough effect to be of concern. The educated citizen will also need to know that the accelerated rate at which man-made greenhouse gases are being added to the atmosphere presents a serious threat. Make certain that no change to the article serves to mask the reality. --Minasbeede 17:49, 30 September 2007 (UTC)

What the hell are you talking about?

This is a simple paragraph to say where greenhouse gases come from, what is currently in the article is WRONG and should be changed as soon as possible, for something that important to the subject at hand to be wrong is a major problem. It is clear the paragraph cannot stay in its current state, if you do not like my new version feel free to suggest an alternative....all we are trying to do is say where greenhouse gases come from.

Restepc 05:29, 1 October 2007 (UTC)

Well maybe you should carefully and fully describe just how the current paragraph is "misleading." Apparently it doesn't say or imply something you want it to say or imply. That doesn't equate to "misleading."

The paragraph say the gases are components of the atmosphere. That's true.

The paragraph says the gases contribute to the greenhouse effect. That's true.

The paragraph says some greenhouse gases occur naturally. That's true.

The paragraph says others result from human activity. That's true.

The paragraph gives the example of burning fossil fuels such as coal. That's valid.

The paragraph says greenhouse gases include water vapor, carbon dioxide, methane, nitrous oxide, and ozone. That's true.

So how is it misleading? How is the article "WRONG"? What are you talking about?--Minasbeede 14:08, 1 October 2007 (UTC)

Saying some gases come from natural sources and some from human activity gives the impression that gases are either natural or human caused, which is higly misleading. I am amazed you could not see that was my point.

That's what needs changing....another slightly smaller problem is I think there should be an entire section on the sources of greenhouse gases, rather than just giving an example in the intro....and if we are going to give an example it should be the biggest source we use, not burning coal......it is frankly amazing that this article barely mentions natural sources, and appears to be intentionally leaving out the fact that the majority of greenhouse gases come from natural sources. Restepc 17:14, 1 October 2007 (UTC)

Read "Role of WV" above. that seems to cover your concern, at least in part.

As I understand it the gases are either natural or human caused. How is that misleading? What false conclusion might a reader reach from reading that? I still see that paragraph as just being introductory. Greenhouse gases serve to make the earth warmer. Some of the GG in the atmosphere are there naturally, some result from human actions. What's wrong with that? --Minasbeede 17:31, 1 October 2007 (UTC)

Amazed you can't see it....do you mind me asking if English is your first language? In nay case you are the only person in this discussion who doesn't see the problem with it, so I'm changing it, if you have a problem with my new version please say what it is and we can discuss it, but it certainly can't stay as it is.

EDIT: Okay I've changed it now, but decided to say 'but human activity also contributes to many' rather than 'human activity also contributes to some' Restepc 20:52, 1 October 2007 (UTC)

As per MB, your new intro was misleading, so Ive reverted it William M. Connolley 21:10, 1 October 2007 (UTC)

Your edit collided with mine that contained a "hint" that someone should revert. I'll take out my wording now, too. It was good the way it was. --Minasbeede 21:19, 1 October 2007 (UTC)

MB, you said in reply to someone making the same argument I am now "there are naturally occurring greenhouse gases, there are man-made greenhouse gases."

This is wrong....there is ONE manmade greenhouse gas...there are not some gases which are natural and some which are manmade....the vast majority come from both natural sources AND human sources. The article in its current form reads to an uneducated reader as if there are some natural gases (eg watervapour) and some human-caused gases (eg CO2).

This is highly misleading at best and a lie at worst, it can not remain as it is.

William, as I've said if anyone has a problem with my new version I'd like to know what it is, and what they would suggest instead. When I am next on a computer which doesn't lag out when I try to edit wiki, I will make another attempt at re-writing it, if you have a problem with that change as well please either tell me what your concerns are so we can work on a version we all agree on, or change it yourself to something else, please do not revert it to the old misleading version. Restepc 22:17, 1 October 2007 (UTC)

You are reading into that paragraph something that isn't there. Also, it's hard to figure out how "the vast majority come from both natural sources AND human sources" contradicts "there are naturally occurring greenhouse gases, there are man-made greenhouse gases." The two say basically the same thing. --Minasbeede 23:04, 1 October 2007 (UTC)

In my view they say opposite things, the current version appears to suggest that some gases are entirely natural and some gases are entirely man-made, three seperate users mentioned this issue in September, even if you do not see the problem it is obvious that other people can, so it needs to be changed. If you have a problem with what I have suggested please say what it is and we can discuss it, but the article can not stay as it is.

The current version reads "Some greenhouse gases occur naturally in the atmosphere, while others result from human activities"

perhaps you can better see my point if you compare that to the sentence 'Some cars are made in France, while others are made in Germany' Restepc 23:27, 1 October 2007 (UTC)

Given that cars are made in Japan, the United States, Mexico, Canada, Russia, and lots of other places that's a really bad example.

The paragraph could be very explicit, perhaps, and say that "of the greenhouse gas molecules that are in the atmosphere some arose naturally while others were man-made" - but that's cumbersome. Also, except for species that are man-made, once the gas is in the atmosphere there's no way to tell, for gases that could be of either origin, what the origin of a particular molecule is.

The paragraph isn't meant to divide greenhouse gas species (methane, CO₂, etc.) into two mutually exclusive types, it's just meant to indicate that of the greenhouse gases in the atmosphere some arise naturally, some are man-made. It's not a grand, definitive exposition of the sources of greenhouse gases, it's just something that indicates greenhouse gases arise both ways: naturally, and from the activities of man. If three separate users misinterpreted the paragraph then perhaps it can be better written but the solution does not seem to lie in the direction of identifying gases according to whether they're natural, man-made, or both. That's not what the paragraph is meant to do: it's just an introduction. Reciting all the various gases and saying whether they're natural, man-made or both (as they occur in the atmosphere) makes the paragraph cumbersome. --Minasbeede 00:00, 2 October 2007 (UTC)

How about something like

"Greenhouse gases are components of the atmosphere that contribute to the greenhouse effect. The majority of greenhouse gases come mostly from natural sources but are also contributed to by human activity. Greenhouse gases include water vapor, carbon dioxide, methane, nitrous oxide, and ozone."

Or possibly to be more specific this would be better

"Greenhouse gases are components of the atmosphere that contribute to the greenhouse effect. The five most common greenhouse gases come mostly from natural sources but are also contributed to by human activity. Greenhouse gases include water vapor, carbon dioxide, methane, nitrous oxide, and ozone."

Unfortunately I'm not sure if that's entirely correct...I don't know the figures for Ozone.... Restepc 02:06, 2 October 2007 (UTC)

Why do almost all the graphs lie?

Almost all graphs show a significant increase in C02 in the atmosphere. But the graph only goes from 300 something to 400 something. This will give the graph an exponential look, instead of a logaritmic look.

Basicly it makes the graph look more dangorus. —Preceding unsigned comment added by Vifteovn (talk • contribs) 09:31, 14 September 2007 (UTC)

The concern isn't over the total amount of greenhouse gases, the concern is over the increase in greenhouse gases due to human activity. That increase is exponential, is it not? It's not T that is the concern, it's ΔT - and ΔT is mostly driven by Δ(greenhouse gases.) The Δ is positive for both. --Minasbeede 18:15, 30 September 2007 (UTC)

I wouldn't say lie, but they are certainly highly misleading if I had the skills to edit the graphs I would. Restepc 05:48, 1 October 2007 (UTC)

Should the "temperature increase" graph be altered to start at 0° Kelvin (making it much taller)? That would make far more obvious how small a 1° change in average temperature is. The Kelvin temperature scale is the proper scale to use when considering the relative magnitude of the change. It's also the proper scale to use for gases and the proper scale to use when discussing (photon) radiation. --Minasbeede 14:20, 1 October 2007 (UTC)

That's an ad hominem argument MB. —Preceding unsigned comment added by Restepc (talk • contribs) 22:27, 1 October 2007 (UTC)

Whoops, forgot to sign Restepc 22:56, 1 October 2007 (UTC)

Name that hominem. --Minasbeede 22:59, 1 October 2007 (UTC)

eh, too tired to explain....just headed to bed....let's sort out one issue at a time :) Restepc 23:34, 1 October 2007 (UTC)

If the graph has legible labels on the axes, then I don't have a problem with adjusting the ranges graphed to make plain the trends. However, most of the graphs in this article have illegibly tiny axis labels, with the result that the graphs are highly misleading to the casual reader. The effect is to exaggerate the rates of change of whatever is being graphed, and promote a particular POV. That needs to be fixed. NCdave (talk) 22:16, 15 March 2008 (UTC)

I run a fairly high resolution on a small screen, and most of the graphs are visible and readable to me (with the only exceptions being the one for water vapor and the one for global GHG trends - which both compress a lot of data into a rather limited area). Which graphs do you think are "exaggerating the rates"? --Kim D. Petersen (talk) 00:09, 16 March 2008 (UTC)

I use a very good 19" LCD monitor at its natural 1280x1024 resolution, with normal-sized fonts. Viewing the article in Firefox at normal text size, the main article text looks like 10pt. The image captions look like 9pt. Anything smaller than that is hard to read. The absolute lower limit of legibility is about 5pt, and my guess is that many users will not be able to read 5-6pt text at all. Though "fine print" text in the 6-8pt range is legible, with effort, it is so hard to read that many readers won't bother.

The text in the top graph is tiny, but legible. The smallest text is "(All Sources and Sinks)" which is about 5pt.

Most of the key text in the second image (Radiation transmitted by the atmosphere") is just barely legible. The tiniest is "Downgoing Solar Radiation" and "Upgoing Thermal Radiation" at the top, which are about 4pt. It is arguably "legible," but I think only because I already looked at the large version, and know what it says.

The smallest text in the third image (the pie charts) is illegible. It is the text at the very bottom, and it appears to be about 3pt.

The fourth image is the "Equilibrium global mean temperature increase above preindustrial" graph. The text is about 5pt, and just barely legible, if I strain.

The text in the fifth image, with the world map, is about 1-2pt, and completely illegible.

The text in the sixth image also varies from about 2pt to about 5pt. Most of it, including the axis labels, is too tiny to read. If you view the large version, you can see that the Y-axis does not start at zero, which is a problem when the axis labels are illegible.

Most of the text in the seventh image ("Global fossil carbon emissions") is about 5pt in size, and just barely legible, if I strain.

The text in the eighth image, with the world map, is about 1-2pt, and completely illegible.

The five graphs in the ninth image "Global trends in major greenhouse gases to 1/2003," have both captions and axis labels which are 1-2pt in size, and far too tiny to read. All of them have Y-axes which start at above zero, thus exaggerating the trends that they illustrate. These are the worst, and the problem is exacerbated by that fact that these are arguably the most important graphs in the article.

The text in the tenth image, with the world map, is about 1-2pt, and completely illegible.

The text in the eleventh image (maps relating to carbon monoxide) is about 2-4pt, and much of it is illegibly tiny. NCdave (talk) 01:36, 16 March 2008 (UTC)

I think that there being text too small to read in such linked graphs is just something we're going to have to live with, however I do strongly agree with NCdave that the "Global trends in major greenhouse gases to 1/2003," graphs become misleading because of this factor, as it is fairly safe to assume that a casual reader will think the graphs start at 0. Restepc (talk) 10:32, 16 March 2008 (UTC)

Please define what 0 (on the axis) should be.

For CO2 should it be 280ppm (just about the static amount over this interglacial 10K+ years)? Or should it be 180ppm (the lowest amount of CO2 over the last 650K+ years). Or should it be 0ppm (a value that has never been seen on Earth (afaik as long as we've had an atmosphere) - and has no realistic relationship with trends or amounts)? --Kim D. Petersen (talk) 23:55, 16 March 2008 (UTC)

As I said, I think it's fairly safe to assume that a casual reader will assume the graphs start at 0, as in 0ppm....the axis labels are too small to read, so the debate currently isn't really what levels they should be at, but rather what impression a layman is currently going to get of what they start at, which is fairly obviously going to be 0ppm....Restepc (talk) 00:03, 17 March 2008 (UTC)

If a casual reader gets that impression, then he is not interested in the graph. Since a perusal of the graph, and the text would quickly fix that misconception.

What is more important is not to indirectly mislead, by placing an arbitrary 0 on a graph, which has absolutely no relation to the context or concept.

Lets take a (extreme but valid) example. Should a graph of temperature start at 0°F, 0°C or 0°K?

By choosing absolute 0 no matter what we are measuring, you are biasing the graph, by not representing the data correctly in context. NCDave quite correctly observed that its the trends, and its relation to the concept measured that needs to be represented. --Kim D. Petersen (talk) 00:21, 17 March 2008 (UTC)

Not scientifically valid perhaps, but nevertheless it is what the casual reader will assume, and it is for those readers that wikipedia should be written...and I can't see the relevance of your temperature example, why not use what we're actually talking about instead?

Perhaps the best way to solve the problem would be to enlarge the graphs as they appear on the main page.....or replace them with one(s) which can easily be read, as the current situation does indirectly mislead.

Restepc (talk) 00:39, 17 March 2008 (UTC)

In which way is it indirectly misleading. If the graphs are presented correctly according to the concept that they describe - ie. no exaggeration of trends, in a scale that presents them without taking a stand. Then i really can't see what your problem is.

As an example take the first graph (carbon dioxide concentration) - that Y-axis is chosen so that if you wanted to display the CO2 content over the last 10K+ years - it would fit. Choosing another axis (for instance starting at 0ppm) on the other hand would indirectly mislead. --Kim D. Petersen (talk) 22:49, 17 March 2008 (UTC)

I think you misunderstand me, the graphs themselves are fine, or at least acceptable (if I was going to be pedantic I'd suggest minor changes but it's not high on my list)...but only when viewed correctly, I don't object to the scale used currently, I'm simply saying that because they're too small to read, people are extremely likely to assume that they start at 0, which considerably exaggerates the trend, giving people like Vifteon a legitimate reason to accuse the article of 'lying' Restepc (talk) 10:30, 18 March 2008 (UTC)

This entire discussion is weird. The graphs have their axes scaled so that they fit and there isn't loads of white space. This is obvious. If you think the legends are too small, feel free to make them bigger, or source better ones, or whatever William M. Connolley (talk) 23:16, 17 March 2008 (UTC)

In the absence of legible axis labels, zero should be zero. Otherwise the graphs are severely misleading, and exacerbate the POV-bias of the article, by making modest increases appear to be enormous increases.

However, I do not believe that it is necessary for the big versions of the graphs to be identical to the small ones. We could make small ones with illegible axis labels, and the Y-axis starting at zero, which link to the current big versions with legible axis labels, and the Y-axis starting at greater than zero. NCdave (talk) 06:02, 19 March 2008 (UTC)

I don't know what you are talking about. Of the images in this article, only three include graphs with an offset zero, and even though the writing is small, in each case I have no problem telling that they have an offset zero from the small graph. Dragons flight (talk) 06:23, 19 March 2008 (UTC)

Dragons obviously have much better eyesight than middle-aged men. NCdave (talk) 07:49, 19 March 2008 (UTC)

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 [9], 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. [10] 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)

Suggested reformat of article

The article is currently lopsided, and one suggestion about how to fix this is to have a section about natural sources of GHGs.

In the same way that I think that saying what proportion of GHGs are of human origin is by far the most logical thing to have at the start of a human GHG emission section, I think that saying what proportion of GHGs are of natural origin is by far the most logical thing to have in the natural GHGs section.

I may be psychic, I may not, but I am getting the impression that going down that path is a surefire way to get the global warming argument to come together with the neutrality argument and spawn lots of little baby arguments which keep shitting themselves and puking on people.

I suggest, that as the title of the page is 'greenhouse gas' we focus on the gasses. Scrapping the human section and the natural section idea, we simply have an introduction, a quick summary of the greenhouse effect, and then the rest of the article should be about the gases....CO2 having it's own section, methane it's own, water vapour, ozone, CFCs etc

Each section showing the global warming power (I forget the official terms), staying power, the amount in the atmosphere now...trends over human history, trends over a geological timescale (not for CFCs of course), and showing all the sources and sinks for each gas....and whatever else people want to put in.

This would mean that there would be an obvious place for any relevant information, and I strongly suspect it would make discussions about the article go much smoother. It also seems a more logical layout to me.....

Thoughts/comments welcome. Restepc (talk) 20:22, 15 March 2008 (UTC)

I've added sections on CFCs and Methane to illustrate my point, let me know what you think. Restepc (talk) 06:56, 16 March 2008 (UTC)

Further added Nitrous oxide and ozone sections, will leave a CO2 section well alone for the time being. I think the ozone section could do with some work. Restepc (talk) 10:57, 16 March 2008 (UTC)

Pasting in large sections from the methane article is just pointless duplication. You want

Main article: methane

William M. Connolley (talk) 12:19, 16 March 2008 (UTC)

No, it's highly relevant duplication. Would you say that this articles section on the greenhouse effect is pointless because there is already an article on the greenhouse effect?

I am of the opinion that this article should have a section about methane as a greenhouse gas.....I can't imagine that you would disagree with that?

Feel free to edit what I have done if you feel there is something not relevant Restepc (talk) 12:30, 16 March 2008 (UTC)

Holy fucking shit.

I am of the opinion that wikipedia should have information about methane as a GHG. It does. Its in the methane article. That shouldn't be duplicated. What *this* article can usefully do is synthesise and compare amongst the various different gases William M. Connolley (talk) 12:42, 16 March 2008 (UTC)

I feel like I'm banging my head against a wall here, I appreciate you may feel protective over an article you have put so much work in but this is insanity. How do you suggest we get around this?Restepc (talk) 12:44, 16 March 2008 (UTC)

This article in it's current form is far from being neutral (I know you disagree with me on that, but you can at least accept that myself NCdave and plantsurfer are of this opinion, and therefore likely other people are too). I saw this as a simple way to fix that problem, I also don't believe the various different gases can be successfully lumped together, as the state of the article demonstrates. Restepc (talk) 12:51, 16 March 2008 (UTC)

To clarify, I started typing 'I feel like I'm banging.....' as a replacement for 'holy fucking shit' before I saw wills comment 'I am of the opinion that wikipedia should have information about methane as a GHG. It does. Its....'

I remain of the opinion that my additions to the article were an improvement. Restepc (talk) 23:36, 16 March 2008 (UTC)

Canvassing ahoy

[11]. 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 ([12]), 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 it.

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)

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)

See also section

I have trimmed the see also section, I think there are more links that could be cut but have limited myself to removing those which appear to be the most obviously non-relevant in the hope that my edits today won't simply be reverted when kim and will get back...

There were also a couple of links to pages that don't even exist, and one to a page which was obviously a mistaken link, I'm going to put Earths Atmosphere in there, for obvious reasons.

Restepc (talk) 09:53, 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)

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)

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)