Talk:Carbon dioxide

Older discussion (March 2005 and earlier), including a lengthy debate on % increases, is archived here.

Paleo history of CO2

The page currently gives this source for a graph showing CO2 in the distant past: http://www.geocraft.com/WVFossils/PageMill_Images/image277.gif It's schematic, and the temp curve is substantially incorrect. I suggest changing it to Royer et al (2004). http://www.gsajournals.org/gsaonline/?request=get-document&doi=10.1130%2F1052-5173(2004)014%3C4:CAAPDO%3E2.0.CO%3B, Fig 1. I'll do this if no-one objects :) Tom Rees Tomrees 16:24, 23 Jun 2005 (UTC)

What's the deal with subscript notation?

The two ways to format subscripts (and superscripts) render identically in my browser (Opera 7.54). So what is the "best" format: '''CO{{subst:sub|2}}''' CO₂ or '''CO<sub >2</sub >''' CO₂ and why? The former requires fewer keystrokes, although I'm more used to the HTML form. Vsmith 19:33, 16 Apr 2005 (UTC)

The former form {{subst:sub|2}} uses a template and results in identical HTML as ₂ being sent to your browser, hence they would never look any different. Templates live in the template namespace and can be accessed by going to Template:template_name, i.e. Template:sub. The advantage of using templates such a {{stub}} is that it will take whatever text is on the page Template:stub and insert it into all pages including the tag: "{{stub}}". You can also pass parameters to templates to customize them. In the Sub example, the "2" is the parameter being passed to the Template.

Templates can be used in two ways either {{template}} or {{subst:template}}. The subst: in the second form tells the wiki to immediately substitute the entire current text of template into the page (i.e. {{subst:sub|2}} becomes ₂ even in the edit window). The form without the subst: causes the text to inserted only when the page is loaded, i.e. wikipedia looks up the current form of template each time the page is viewed. This has the advantage that changing the text at Template:template can immediately change what is presented in all places it occurs.

The drawback is that looking up {{template}} each time a page is loaded increases server load. For this reason, some people feel that for things like subscripting, which are both pervasive and unlikely to change, that {{subst:sub|2}} should never be used, and only {{subst:sub|2}} or ₂ should be used. After all, each of these produces identical code for the browser. I assume this is why Cburnett replaced the templates. As far as I know, there is no hard and fast policy on this. Dragons flight 22:27, Apr 16, 2005 (UTC)

Thanks! Now will I remember all that? Guess I'd best apply it soon. :-) Vsmith 23:46, 16 Apr 2005 (UTC)

Yes, that's why I did it. There's no real need to force subscripts and superscripts to use a template other than ease of editting (I've actually posed an enhancement that would make it easier by doing 4^^th^^ or 4\\th\\ for superscript and CO^^^2^^^ or CO//2// for subscript) since the sub and sup HTML tags will probably never change in HTML. Using templates for such only serves to increase server load... Cburnett 00:26, Apr 17, 2005 (UTC)

Another solution is Unicode. The superscripts are 0x207x and the subscripts 0x208x, as in CO₂. —BenFrantzDale 13:55, 4 November 2005 (UTC)

CO2-only greenhouse

Is it meaningful to discuss the greenhouse effect of a single atmospheric component, as if that could be divorced from the effects of other atmospheric components? If the IR absorption spectra of, say, CO₂ and water overlap at all, then the effect of adding more carbon dioxide will depend on how much water vapor is already in the air. And even if they don't overlap, then the amount of outgoing radiation absorbed by one component depends on the spectrum of the outgoing radiation, which depends on the temperature of the radiation source, which depends on the strength of the greenhouse effect of all the other components.

It seems to me that there are multiple plausible ways to deconvolute the effects of a multiple-component greenhouse, and so this statistic is ripe with potential to spin the result one way or another.

You are right. While, it is not entirely implausible to define the greenhouse effect of one component (say by asking how much the effect would change by removing all of that component and leaving everything else constant), there are a number of concerns with respect to how one defines that number and people having different ideaologies can reasonably quote different values depending on how they choose to approach the problem. Consequently, any single value is pretty much inherently POV. I am going to remove that recent addition. If the author wants to quote a range of values representative of the NPOV spectrum and add a discussion of the various ways the contribution of CO₂ is defined, then I wouldn't object to that. Dragons flight 17:22, Apr 29, 2005 (UTC)

PS. Please sign your statements on talk pages with 4 tildes ~~~~.

Indonesian peat fires...

The article sez:

with Indonesian peat fires recently releasing 13-40% as much carbon as fossil fuel burning does

This has no source. Nor does it state if this is per year; per all time; fossil fules globally or in indonesia... in short, its coming out unless backed up and explained. William M. Connolley 18:43:22, 2005-09-09 (UTC).

The source is in #Peat fires in peat link above. (SEWilco 20:48, 9 September 2005 (UTC))

Subtle, and not really very helpful. Ive made it rather more explicit. William M. Connolley 21:21:56, 2005-09-09 (UTC).

Merge from dry ice

There was no consensus for the merge here from dry ice. I suggest splitting it out again. Gene Nygaard 22:08, 19 October 2005 (UTC)

Yeah, I agree. I was surprised to see it moved here. There was a comment on the Dry Ice page yesterday... not sure where it went.--Bookandcoffee 17:36, 20 October 2005 (UTC)

Here's the text from Talk:Dry ice (which you can still get to by clicking the "redirected from" link at the top of the page -- I don't know any way to code no-redirect into a wikilink):

I agree we should move the physical properties out to the CO2 article. Dry ice, however, is unique amongst solids in that most people think about it separately from the gas. Thus I think it should stay as a separate article. Samw 23:52, 18 October 2005 (UTC)

That is fine with me. It was the mismatched physical properties that I did not like. Feel free to do whatever you think will improve the article. Bobblewik 18:06, 19 October 2005 (UTC)

Zack 01:58, 21 October 2005 (UTC)

Question

Does anyone know the temperature at which CaCO₃ decomposes to CaO + CO₂ ?

I am asking this in view of venus' atmosphere. 84.160.210.182 20:10, 4 December 2005 (UTC)

• According to our article on calcium carbonate, it is 825 °C, which fits with my vague memory of the value. This is at least 300 °C higher than surface temperatures on Venus. Physchim62 (talk) 10:37, 5 December 2005 (UTC)

So this could not have been the source of CO₂ aon venus. Thank you for the fast answer. 84.160.238.22 20:35, 5 December 2005 (UTC)

PaCO2 Mention?

Considering the biological details included in this article, shouldn't a link to the Blood gas application of partial CO₂ pressure in medicine be included?

• I've added it as a "see also" for the time being, rather than mess around too much with a well written biology section. It is there for next editor to include in the text. Physchim62 (talk) 09:36, 11 December 2005 (UTC)

Carbonic acid from CO2

I need to know the minimum pH that can be obtained by passing CO2 through water a approximately 2bar. Can anyone help me with this one.

Thank you for your time

refrigeration

"Liquid and solid carbon dioxide are important refrigerants, especially in the food industry, where they are employed during the transportation and storage of ice cream and other frozen foods." Dry ice is used for shipping small quantities of frozen items like medical samples or frozen food but I don't think it's used as a refrigerant is it? --Gbleem 03:46, 27 December 2005 (UTC)

I found this : http://www.hepco.co.jp/english/research/develop/result2004/res2004-04.html

Liquid CO2 can be used as a conventional refrigerant in industrial circumstances, where it has the advantages of being cheap and non-toxic. The pressures required (50 bar) mean that it is impractical for domestic use. Physchim62 (talk) 08:40, 7 June 2006 (UTC)

Question about capturing CO2

I'm trying to find out what the methods are for capturing, or seperating CO2. Many coal powerplants are using algae photobioreactor systems to reduce their NOX and CO2 emmisions, but i haven't been able to find out how they seperate the CO2 from the smoke and particulate matter in order to feed it into the algae system.

Also, aside from plants, is there any way to capture/collect/seperate, the ambient CO2 in the air.

Are there any matireals that could be used to absorb CO2, and then later release it.

Aside from pressurizing CO2, is there a convienient way to store it,(perhaps a large tank).

How do submarines deal with the buildup of CO2.

Is there an efficient way of producing C02, (gasification of coal, etc)

If anyone has information about any of these questions, please post it in the CO2 article.

-Daemon

How to measure carbon dioxide

Does anyone know of a way to measure the volume of CO2 when it decomposes from copper carbonate to Copper oxideand carbon dioxide?

organic or inorganic

I was answering questions from my biology book and a question came up, is carbon dioxide organic or inorganic?

There was a paragraph in the book that said, organic compounds are either found or made by living orgainism, all other compounds are inorganic. Some inorganic compounds thats are essential to living organisms include water, minerals ... and carbon dioxide.

So is it organic or inorganic. Or do I just answer it as both organic and inorganic?

High concentrations of CO2 poisonous?

It says that concentrations of more than 5% of CO2 is poisionous, and this is hinted in articles like Apollo 13, but pages like Asphyxia and Limnic eruption just hints that the CO2 is displacing the oxygen. When I see that we usually breathe out 4.5% CO2, and 5% is poisionous, I start to think that our lungs are not capable of getting rid of CO2 if there is too much CO2 in the air ... is that right? tobixen 19:26, 24 May 2006 (UTC)

• The level of carbon dioxide is the main signal used by the body to ensure the correct breathing rate: see air hunger. So yes, excessive levels of CO2 in the air screw up one of the most important control mechanisms in the body, I think that can be defined as "toxic"... Physchim62 (talk) 08:44, 7 June 2006 (UTC)

Is plant biomass in the northern hemisphere really responsible?

The article currently claims:

Because of the greater land area, and therefore greater plant life, in the northern hemisphere as compared to the southern hemisphere, there is an annual fluctuation of about 5 µL/L, peaking in May and reaching a minimum in October at the end of the northern hemisphere growing season, when the quantity of biomass on the planet is greatest.

According to the Phytoplankton article, "Through photosynthesis phytoplankton produce approximately 98% of atmospheric oxygen."

This doesn't seem to add up. Perhaps phytoplankton removing CO2 from the oceans doesn't affect atmospheric CO2 as immediately as land plants do. Perhaps seasons don't effect phytoplankton CO2 consumption as much as they do land plants. Perhaps lots of things that I'm not thinking of contribute to making the "greater land area in the northern hemisphere" statement correct.

My initial reaction however, is that this explanation needs some confirmation.

If you can watch flash, you should view the movie at http://www.daac.ornl.gov/NPP/npp_home.html. This shows the intensity of primary productivity, or carbon fixation, over a multi-year period. You'll see that terrestrial primary productivity can be far more intense, and is far more variable with the seasons, than marine primary productivity.

Honestly, the 98% marine number strikes me as strange, unless it might be based on some confusion between gross and net primary production: maybe phytoplankton do an enormous amount of photosynthesis compared to terrestrial plants, but also consume almost all the resulting oxygen through their respiration. I don't know. Shimmin 22:31, 29 June 2006 (UTC)

% of C02 in atmosphere error ?

I think that the %figure,.035% routinely used for the amount of CO2 in the atmosphere is in error. This figure is routinely seen on websites used by schools and, in fact, everywhere. The bulk of the air is Nitrogen78%, Oxygen21%, and only .9% (nine tenths of 1 % is left for trace gasses, C02 is .035% of the trace gasses only, not of the whole atmosphere, which makes it even less than Xenon. This in turn makes it only .000350% of the whole atmosphere. So, if C02 has increased from,lets say, 350 ppm to 380 ppm in the last 100 years, this is an increase of 30 ppm in 100 years .00003%. If this is not correct I'd appreciate some professional help.Willyger 23:53, 5 July 2006 (UTC)

380 ppm means that it corresponds to 380/1,000,000 times the volume of the total atmosphere, or 0.038%. The figure is correct though 0.035% would be rather out of date. Dragons flight 00:06, 6 July 2006 (UTC)

I concur with the percentage, 380 ppm = 0.000380 fraction = 0.038%. But now I think that the estimate of the mass of C02 is horribly off. The article on earth's atmosphere indicates that the mass of the whole atmosphere is 5,000 trillion tons (5E+15 tons). The current article indicates that the atmosphere is 0.057% CO2 by weight, which would give a C02 mass of 2.85E+12. The article however gives a value of 2.94E+9, a difference of three orders of magnitude! I couldn't source the 2.94E+9 number. Can anybody else? Sethery 04:57, 12 July 2006 (UTC)

Sethery, you are correct. The mass of CO2 in the atmosphere should be 2.9E+12 metric tonnes. For example: http://cdiac.ornl.gov/pns/faq.html gives t 1 ppmv of CO2 = 2.13 Gt of carbon. Thus 380 ppmv = 809E+9 metric tonnes of C. And converting to the mass of CO2, (using 3.664 g CO2/ g C) gives 2.965E+12 metric tonnes of CO2 in the atmosphere. I've modified the article. --B Carey 18:21, 15 July 2006 (UTC)

Available Fraction error?

This article says, "The ratio of the emitted CO2 to the increase in atmospheric CO2 is known as the airborne fraction." Isn't this backwards? For example, "airborne fraction—The fractional amount of carbon dioxide, CO2, that remains in the gas phase relative to a given increase in the total amount of CO2 (atmosphere and ocean combined)," according to the Glossary at the American Meteorological Society, http://amsglossary.allenpress.com/glossary/search?p=1&query=airborne+fraction&submit=Search. Jedwards05 03:43, 11 July 2006 (UTC)

    I originally posed this CO2 % question after seeing  http://anthro.palomar.edu/adapt/atmospheric_gasses.htm
   this lists trace gases as % of the atmosphere (all trace gases put together are .9%) Argon 0.934%, Neon 0.0018%, Helium 0.000524%, Methane 0.0002%, Krypton 0.000114%, Hydrogen 0.0005%, Nitrous Oxide 0.00005%, Xenon 0.0000087%.
  I'm not an academic, but since they don't even list CO2 in this chart, I'm assuming that it is less than Xenon, and as I originally asserted, that would make it 0.0000350%, but it would make it .035% of the .9% of trace gases, no? Willyger Willyger 00:29, 23 July 2006 (UTC)

What?!

Surely the line "The three vibrational modes of carbon dioxide: (a) symmetric, (b) asymmetric stretching; (c) bending. In (a), there is no change in dipole moment, thus interaction with photons is impossible" under the co2 model must be completely wrong. Why would it have an absorption spectrum if it didn't have any interaction with photons??!--Deglr6328 03:53, 21 July 2006 (UTC)

Mode (a) cannot be excited by IR absorption. Modes (b) and (c) do change the molecule's dipole moment, and can be excited by absorbing photons. Shimmin 01:07, 23 July 2006 (UTC)

ppm vs µL/L

These units seem to be interchangable. Should we just stick to one or the other throughout the article?--71.52.169.173 17:10, 23 July 2006 (UTC)

If ppm are to be used, then they should be specified as ppmv, for precision. WMC could state this with far greater certainty than I, but it seems to me that ppmv are the units most frequently used when atmospheric scientists discuss CO2 concentrations in the earth's atmosphere. However, at some point in the past SI zealot Gene Nygaard saw fit to replace all instances of ppmv with µL/L, and no one saw fit to made an edit war out of it, and so it has remained thus to this day. Shimmin 19:03, 23 July 2006 (UTC)