Talk:Greenhouse gas

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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.

(Don't forget to sign.)

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 degree 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)