Talk:Methane

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I have significant misgivings about the CH4 figures given in the table attributed to Houweling et al. (1999).

From reading papers such as

Nature 439, 187-191 (12 January 2006) | doi:10.1038/nature04420 Methane emissions from terrestrial plants under aerobic conditions

Frank Keppler1, John T. G. Hamilton2, Marc Bra1,3 and Thomas Röckmann1,3

This information on CH4 emissions is potentially grossly understated as plant matter is not listed as a source of methane emissions to the atmosphere. The authors reach a conclusion that CH4 emmissions of 62–236 Tg yr-1 for living plants and 1–7 Tg yr-1 for plant litter. The range forliving plants is large but even at the lower end of the range it indicates that there is a significant CH4 contribution from living plants that has not been taken into account in Houweling et al (1999).

Similarly the estimate and comment that livestock contribute 35% of the Anthropogenic Emissions may well be a considerable exaggeration of their contribution. One example from a paper by Johnson KA, Johnson DE. Department of Animal Science, Washington State University, Pullman 99164, USA. 1995 comes to the conclusion that cattle will contribute some 2% of CH4 emssions over the next 50 - 100yrs. The USDA determined some years ago that livestock emmissions in the USA represented some 0.005% of total GHG emmissions. Use the following URL reference to look at their abstract and linked papers.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?itool=abstractplus&db=pubmed&cmd=Retrieve&dopt=abstractplus&list_uids=8567486

Similarly recent research into CO2 natural sequestration within the oceans through remineralisation of CO2 released by life within the oceans has been overestimated by between 20 - 50% representing according to the authors approximately 3Pg/yr of CO2 finding its way into the atmosphere that has not been previously accounted for. If the ratio of CO2 to CH4 of 220:1 is maintained there is potentially another unaccounted for source of natural CH4 emissions.

Monitoring of atmospheric concentrations of CH4 were found to decline during the 1997/98? el nino event and this reduction was assigned to the fact that substantial wetland drying occured during this periond. Later ongoing research has not yet been published as the paper that contained this information was released after the 2002/03 el nino and we are now even further behind having just experienced el nino 2006/07.

--Anechidna1 12:56, 7 May 2007 (UTC)

Contents

[edit] Methane climate history

Could someone do a graphic showing the methane atmospheric climate history - I've read that ice cores can be used for it and have seen some articles related to it, but nothing with a graph showing concentration vs time (other than since the 1970s and such). LetterRip 22:34, 27 October 2007 (UTC)

[edit] methane asphyxiation

"Methane is an asphyxiant and may displace oxygen in a workplace atmosphere" , so it's perfectly safe to breathe methane "on the patio, in the car, or on the boat -- wherever good times are had" as long as it's not at work where employer liability make methane deadly ! ;) (I hope methane is actually heavier than air...)

Well, where else (besides a laboratory, industrial site, etc) would one encounter large enough quantities of methane that could displace oxygen? 130.134.81.16 15:06, 11 July 2007 (UTC)


[edit] I smell Bullshit

A recent article (July 3, 2007) from the associated press blames methane accumulation in a manure *pit* for the asphyxiation deaths of 5 farmers, all related. Last I checked, this stuff is about half the weight of air, that is, it would have near half the lifting power of helium. There's just no reasonable way to imagine it could accumulate in a pit, and even in a covered pit if it asphyxiated anyone it would have had its effects at the opening of the pit rather than at the bottom of the pit, as the AP release said.

Whats really going on here? Some other toxic component of the pit gas perhaps? NOx or H2S increased by the runoff from the cattle feed located nearby?

The story as it changes is found at news.yahoo.com/s/ap/20070704/ap_on_re_us/methane_deaths

Zaphraud 18:07, 4 July 2007 (UTC)

[edit] Check Scientific America

Im not sure if Im doing it correctly, but anyways, check Scientific America February 2007 pages 53 to 57, may help you about methane and global warming and the production of this gas by plants.

[edit] Global warming potential

The GWP of methane is reported as 21, 22 and 29 on various pages - "Methane" and "global warming potential" - is this an inaccuracy or is there some doubt over what the figure actually is? Or is it a variable depending on other factors? --Bug

There are 2 factors here. The first is the timescale which you calculate the GWP for - methane is rremoved from the atmosphere with a lifetime of about 9 years i.e. quicker than CO2 so it becomes relatively less important over longer periods of time. TAR[1] gives 62, 23, 7 for 20 years 100 years and 500 years. The second source of confusion is that there is some uncertainty in the removal rate of methane. It cannot be measured directly but has to be modelled or deduced from other observations. This leads to the uncertainty. I recomend:
  1. A GWP is meaningless without indicating the timescale for which it was calculated
  2. All quoted GWP figures should be sourced.
--NHSavage 08:54, 18 January 2006 (UTC)
Now made necessary changes to the article.--NHSavage 22:39, 18 January 2006 (UTC)


Methane is a greenhouse gas with a global warming potential of 22. What does this sentence mean ? --Taw

Global warming potential is a measure of how much global warming a gas causes, relative to carbon dioxide. Unfortunately I don't understand all the technical details, but I think it means that a given mass of methane causes 22 times as much global warming as the same mass of carbon dioxide. -- SJK

What is measured ? How much warming is caused by the same volume of gase, the same weight of gas or by yearly emmision of gas ? --Taw

The same mass.--NHSavage 22:39, 18 January 2006 (UTC)

I believe it is how much a given mass of the gas warms the earth in a given period, compared to how much the same mass of CO2 warms the earth in the same period, but you'd have to check. -- SJK

If it's a real concept, we need an article: global warming potential.

That article exists. Issue resolved. - SEWilco

It says methane is eight times stronger than carbon dioxide as a greenhouse gas in the first section (Sources of methane) then says it's twenty times stronger in the "Methane on Earth" section....which is it? -- djohnsto77

Question: I'm no chemistry wiz, but it seems to me that if burning 1 methane molecule produces 1 CO2 molecule, then by extension burning one mole (16 g) of CH4 would produce one mole (44 g) of CO2. Isn't this relevant in terms of comparing the GWP of the two? I.e. burning/oxidizing one ton of methane would produce 2.75 tons of CO2. Therefore, if you take the GWP of CH4 to be 23, burning it would reduce the GWP to 2.75 (a factor of 8.4). Likewise, if you take the 500-year view of GWP and take the GWP of methane to be 7 (I'm getting this from the global warming potential page), burning the methane would still reduce it to 2.75 (a factor of 2.5). Can someone who understands chemistry tell me if this is correct? Worth mentioning? --Potosino 02:15, 4 February 2007 (UTC)

[edit] Error in formula

Shouldn't the number of CO2 molecules produced be 1? CH4 + 6O2 => C02 + 4H2O

yup. fixing -- Tarquin 15:45 Jan 22, 2003 (UTC)

The equation is totally unbalanced. fixing. -Smack 06:09 20 Jun 2003 (UTC)


[edit] Source of statistics?

"80% of the world emissions are of human source." What is the source for this, and the other percentages? --SEWilco 20:25, 1 Sep 2003 (UTC)

USDOE says: "Anthropogenic sources are estimated to be 60 percent of total methane emissions" - http://www.eia.doe.gov/oiaf/1605/ggrpt/emission.html They reference: "Intergovernmental Panel on Climate Change, Climate Change 2001: The Scientific Basis (Cambridge, UK: Cambridge University Press, 2001), p. 248"

A huge amount of methane is created from bacteria in padi fields in china and other asian countries 18:35, 11 December 2006 (UTC) [Luppers]

[edit] Methane - Removal of trace amounts from air

I have a question.no

Are there chemicals that can remove trace amounts of methane from air?

Ideally, it should be possible to extract methane from these solvents to work them in a cyclic manner.

Manu Khemani

email: Manu_Khemani@rogers.com

[edit] Methane in planetary science

May I offer a suggestion: One of the most fascinating appearances of methane (especially since the new results of the Huygens probe on Titan) is in the planetary sciences. Some mention would be nice. See http://www.newscientist.com/channel/space/cassini-huygens/dn6910 for an interesting example. Archie Paulson 19:57, 21 Jan 2005 (UTC)

[edit] Prognostications on first day when Titan methane is burned on Earth

Would this be an appropriate forum to speculate on when the first methane harvested from Titan will be burned on Earth?

Probably not here. And it's easier to use agriculture or fissionables to make methane than ship that light stuff. (SEWilco 15:54, 15 Mar 2005 (UTC))

[edit] Origin of methane

The orgins of methane, according to the article, are mostly biotic, but how then interstellular clouds have methane too? Probably there are some natural inorganic processes which lead to methane, please write more about all of this. This is in some sense the simplest C-containing molecule, so the origins are of particular interest. 203.162.3.147 12:31, 13 Mar 2005 (UTC)

Have some suggested phrasing? See also: Abiogenic petroleum origin (SEWilco 15:49, 15 Mar 2005 (UTC))

[edit] Methane's global warming potential

Is methane's global warming potential 21 or 23? I am unsure about this could someone help me?

According to IPCC Third Assessment Report it is 23. This is a complicated calculation as it must account for how quickly emissions are removed from the atmosphere which is a complex process (the second assesment gave the figure of 21 but as this is based on older data the IPCC TAR figure of 23 should be used). Note also that this is the figure for a 100 year period. If you are interested in shorter or long times the number is different.--NHSavage 22:42, 18 January 2006 (UTC)

[edit] the joule thompson inversion temperature of Methane

Can some one tell me what the joule thompson inversion temperature is for methane?

Any help/suggestion/guidance will be highly appreciated.

warm regards Tony

(tone007@rediffmail.com)

[edit] density

Is methane denser or less dense than air? I realize it should be easy to figure this out from the molecular formula and the density of air, but if it's less dense than air (which I think it is) then that's an interesting fact that might be good to add.

Less dense. About 55% the density of air. I added mention of its being lighter than air to the "...on Earth" section. (SEWilco 15:42, 4 October 2005 (UTC))

Thanks!

[edit] Methane as a fuel

Can methane be used as a Substitute for fossil fuels as a major source of vehicle energy? —The preceding unsigned comment was added by STEVE (talk • contribs) 04:52, 7 October 2005 (UTC)

Much of the widely used fuel natural gas is methane. Natural gas is harvested from underground deposits and contains a variety of hydrocarbons and other gases, much of it being methane. (SEWilco 13:24, 7 October 2005 (UTC))

[edit] Methane entry needs a complete overhall

The information on methane and its presentation is not up to the standard of other articles in Wikipedia.

Much of it is simply unintelligible (perhaps written by people who speak English as a second language?). There are many statements that are, at best, misleading, and at worst complete nonsense, eg: "Methane acts on organic rich shales and produces a minor contribution (1-3%) to form petroleum with true biomarkers as hopanoids and others insaturated hydrocarbons (n-alkenes). Methane interacts with peats, forming coal and bearing mercury, nickel, arsenic,cadmium, selenium, vanadium, uranium and other toxic metals."

Someone with a good knowledge of organic geochemistry AND the English language please should rewrite the entire entry. —The preceding unsigned comment was added by 82.83.210.13 (talk • contribs) .

I will post this at Wikipedia talk:WikiProject Chemicals. Physchim62 (talk) 11:22, 20 November 2005 (UTC)

(copied following from Wikipedia talk:WikiProject Chemicals)--NHSavage 23:18, 18 January 2006 (UTC)

I agree. That article is a real mess. However, the article on methane in the German Wikipedia (http://de.wikipedia.org/wiki/Methan) seem to me to be very good (based on my rusty German). That would probably be a good place to start in order to get the English version up to a higher standard. Edgar181 19:05, 21 November 2005 (UTC)


[edit] Proposed revamped structure

I suggest that the first thing to do on this article is a major reorganisation as followa:

  1. Properties
    1. Reactions of methane
  2. Uses of methane
  3. Sources of methane
    1. Units of measurement
  4. Methane in the Earth's Atmosphere
    1. Emissions
      1. Biological emissions
      2. Industrial emissions
    2. Atmospheric chemistry and concentrations
  5. Extraterrestrial Methane
  6. Miscelaneous
    1. Methane in heraldry
  7. See also
  8. References
  9. External links


Any comments?--NHSavage 23:11, 18 January 2006 (UTC) New revision.--NHSavage 19:37, 19 January 2006 (UTC)

I like this suggested organization. A few possible alterations:

  • separate industrial use of methane (as a chemical feedstock) from its use as a fossil fuel into different sections
  • the "Sources of methane" section could focus on introduction of methane into the atmosphere and a separate section on geological sources could focus on natural deposits from which methane is "mined" for industrial and fuel use
  • the section on heraldry is trivia and can be eliminated -- Edgar181 19:55, 19 January 2006 (UTC)
I am now rewriting in the new structure for draft see: my sandbox--NHSavage 17:09, 21 January 2006 (UTC)
Done. The article IMHO has a better structure and some of the worst elements of the old article are gone. It needs a lot more work but these are now more neatly divided up into sub sections. --NHSavage 18:52, 21 January 2006 (UTC)

[edit] Living plant sources

According to [2] it is 10-30%

Although the scientists have some first indications, it is still unclear what processes are responsible for the formation of methane in plants. The researchers from Heidelberg assume that there is an unknown, hidden reaction mechanism, which current knowledge about plants cannot explain - in other words, a new area of research for biochemistry and plant physiology.
In terms of total amount of production worldwide, the scientists' first guesses are between 60 and 240 million tonnes of methane per year. That means that about 10 to 30 percent of present annual methane production comes from plants. The largest portion of that - about two-thirds - originates from tropical areas, because that is where the most biomass is located. The evidence of direct methane emissions from plants also explains the unexpectedly high methane concentrations over tropical forests, measured only recently via satellite by a research group from the University of Heidelberg.
But why would such a seemingly obvious discovery only come about now, 20 years after hundreds of scientists around the globe started investigating the global methane cycle? "Methane could not really be created that way," says Dr. Frank Keppler. "Until now all the textbooks have said that biogenic methane can only be produced in the absence of oxygen. For that simple reason, nobody looked closely at this."--Paleorthid 03:12, 12 January 2006 (UTC)

And according to [3] it is up to 1/3 based on the same source, but not sure how they figured it quite that high.

The world of climate change science and policy has been rocked by the discovery that plants produce up to one-third of the second most important greenhouse gas.
The findings are published in Nature today (12 January) by a team led by Frank Keppler from the Max-Planck Institute in Germany.--Paleorthid 17:20, 12 January 2006 (UTC)

Quote for "up to 1/3" [4]--Paleorthid 05:18, 14 January 2006 (UTC)

Please see the discussion of this on Talk:Global_warming#Methane. I will try and get a recent review of methane sources and put it on here. One paper a) might be wrong b) might have made incorrect assumptions when it scaled up from plant to ecosystem to global emissions. The dust needs to settle a bit (which is not to say this is not good science - it is an excellent example of how the scientific consensus on a subject can be challenged).--NHSavage 08:22, 18 January 2006 (UTC)
Note that I have now added another reference in which the orginal Keppler et al paper is challenged. This is a very contentious issue at present.--NHSavage 18:38, 23 May 2007 (UTC)

[edit] Methane synthesis?

Can methane be synthesized from electricity and, say, H20 and CO2? I mean, I'm interested from a purely scientific viewpoint and also from a global energy viewpoint. In the far future, where electricity might be generated in large amounts from non-hydrocarbon resources (Geothermal, nuclear fission/fusion, solar, wind...), methane might prove to be a better storage medium for energy than hydrogen. So, how would this happen? I'm sure someone knows the specific name for this process. Robotbeat 23:27, 27 January 2006 (UTC)

Nevermind (see Sabatier reaction). Robotbeat 23:36, 27 January 2006 (UTC)

[edit] rice production

how is this a natural and not an anthropogenic source of methane?—The preceding unsigned comment was added by 165.247.83.38 (talk • contribs) .

Becasue that's how the authors of the study classified it. Their study lumps all wetlands together. None of the other studies quoted in IPCC TAR have a complete set of emissions and I wanted a consitent set of numbers so I chose Houweling et al. There are I think more recent sudies but I do not have time to currently chase up the papers. It is not ideal however.--NHSavage 21:29, 19 February 2006 (UTC)

[edit] Figure size

63.114.24.9 reduced the size of the graph showing methane concentrations from 600 to 250 px. I feel that this is too small to see the details of the graph and that this is an important graph for this section. What do other think - should it be big or little? --NHSavage 08:17, 22 February 2006 (UTC)

[edit] Clarification requested

What does "a Global warming potential of 23 over a 100 year period" mean? -- Beland 02:28, 3 March 2006 (UTC)

Added a claification. For more details see Global warming potential.--NHSavage 08:34, 3 March 2006 (UTC)

[edit] Sudden release from methane clathrates

  1. Woudn't the methane burn, thus
    • Producing short term heating leading to catastrophic methane release
    • Producing up to 100 times the current levels of C02 (and a similar amount of H20 raising sea level 10 cm) and consuming 20% of the oxygen in the atmosphere


Assumptions
Mass of atmos 10^21 g 21% 
* 21% oxgygen = 2*10^20 g
* .04% CO2 = 4*10^17 g
Mass of clathrates "ten million million tons" ~ 10^19 g 
The area of the World Ocean is 361 million square kilometers ~ 4*10^14 m^2 = 4*10^18 cm^2
Methane reaction
CH4  + 2(O2)=> 2(H20) + CO2 
16g  + 64g  => 36g    + 44g

Rich Farmbrough 22:58 21 June 2006 (GMT).

Even allowing the unlikely event that all the methane would be released at once, the lower flammability limit of methane in air is around 5%, so if the released methane was 1% of the atmosphere, it would not form a flammable mixture. Shimmin 03:32, 22 June 2006 (UTC)

[edit] Moved here from science ref desk

[edit] WIKI "Methane Gas" article is DANGEROUSLY UN-Scientific & MISLEADING

This is a VERY serious discrepancy in your article about METHANE GAS because:

  1. YOUR ARTICLE SAYS THAT METHANE GAS IS NOT TOXIC -
  2. HOWEVER, THAT SAME ARTICLE SAYS THAT METHANE GAS IS AN ASPHYXIANT.... WHICH CAN CAUSE A PERSON TO NOT BREATH NORMALLY, CAUSE UNCONSCIOUSNESS, BRAIN DAMAGE AND DEATH.
  3. WOULDN'T THAT BE TOXIC TO LIVING ORGANISMS?
  4. Please see excerpts from article below:

Methane is not toxic by any route. ....... Methane is an asphyxiant and may displace oxygen in a workplace atmosphere. Asphyxia may result if the oxygen concentration is reduced to below 18% by displacement. The concentrations at which flammable or explosive mixtures form are much lower than the concentration at which asphyxiation risk is significant. When structures are built on or near landfills, methane off-gas can penetrate the building interior and expose occupants to significant levels of methane. Some buildings have specially engineered recovery systems below their basements, to actively capture such fugitive off-gas and vent it away from the building. An example of this type of system is in the Dakin building, Brisbane, California. [edit] Reactions of methane The reactions with methane are: combustion, hydrogen activation, and halogen reaction.

Asphyxia (from Greek a-, "without" and sphuxis, "pulse, heartbeat") is a condition of severely deficient supply of oxygen to the body that arises from being unable to breathe normally. Asphyxia causes generalized hypoxia, which primarily affects the tissues and organs most sensitive to hypoxia first, such as the brain, hence resulting in cerebral hypoxia. Asphyxia is usually characterized by air hunger but this is not always the case; the urge to breathe is triggered by rising carbon dioxide levels in the blood rather than diminishing oxygen levels. Sometimes there is not enough carbon dioxide to cause air hunger, and victims become hypoxic without knowing it. In any case, the absence of effective remedial action will very rapidly lead to unconsciousness, brain damage and death.[1] The constriction of the arteries and/or veins in the neck, such as in certain types of strangulations, do not cause asphyxia but rather direct cerebral hypoxia. Asphyxiation or suffocation refer to the process of asphyxia, where the body becomes increasingly hypoxic.

Toxicity (from Greek τοξικότητα – poisonousness) is a measure to the degree to which something is toxic or poisonous. The study of poisons is known as toxicology. Toxicity can refer to the effect on a whole organism, such as a human or a bacterium or a plant, or to a substructure, such as the liver. By extension, the word may be metaphorically used to describe toxic effects on larger and more complex groups, such as the family unit or "society at large". In the science of toxicology, the subject of such study is the effect of an external substance or condition and its deleterious effects on living things:organisms, organ systems, individual organs, tissues, cells, subcellular units. A central concept of toxicology is that effects are dose-dependent; even water is toxic to a human in large enough doses, whereas for even a very toxic substance such as snake venom there is a dose for which there is no toxic effect detectable.

Thank you. —Preceding unsigned comment added by 67.113.165.130 (talk) , at WP:RD/S

(5th edit conflict)Please don't overreact like this. Look, it is simple. Methane is not toxic, but if you ONLY breathe methane, than you die. Humans need OXYGEN not METHANE to live. Also, please sign your posts with a —~~~~ — [Mac Davis] (talk)
Thanks for pointing that out. Would you be able to change the article so it was correct?--Light current 16:07, 21 August 2006 (UTC)
A cushion can be non-toxic, but it could be possible to smother someone to death with it. Toxicity has nothing to do with asphyxiation, IMHO. --Kjoonlee 16:08, 21 August 2006 (UTC)
If you want to discuss articles, the best place would be Talk:Methane. --Kjoonlee 16:08, 21 August 2006 (UTC)
Yeah. Good point. Should this post be moved there. I thnik so!--Light current 16:12, 21 August 2006 (UTC)
Toxicity and asphyxiant are different things, methane is not toxic, breathing methane mixed with a sufficient amount of oxygen does not harm anybody significantly, and one can do that for quite a long time. It is an asphyxiant, indeed, but an axphyxiant is not a toxin. As the saying goes, 'drowning: it is not the water that kills, its the lack of air'. I do not see why the document should be changed. --Dirk Beetstra T C 16:49, 21 August 2006 (UTC)
I think what we're talking about here is the difference between a lay and a technical understanding of the word "toxic". I would say that we should link to the article on toxicity here but I see that is already the case. I think the article is pretty clear on the dangers of methane as it is and find it ironic that the person who is accusing it of being "un-scientific" and "misleading" is the one who doesn't know the actual definition of the word toxic. It basically means "poisonous", not "harmful" or "deadly". Big difference there—lots of things are harmful or deadly that are not poisonous (like falling out of a window). --Fastfission 19:38, 21 August 2006 (UTC)
Quick sanity check for our anonymous guest: Is nitrogen toxic? It makes up 70% of the air we breathe, but if you breathe pure nitrogen, you'll suffocate. At the accelerator where I work we use lots of liquid nitrogen, and if you let too much boil off in a confined space you'll start to get light-headed, because it displaces oxygen. —Keenan Pepper 06:11, 22 August 2006 (UTC)
Just wondering .. an atmosphere of 100% oxygen .. would thát be toxic? After all, then you are breathing in a gas which consists for almost 100% out of radicals .. or worse .. a diradical! And liquid oxygen, can't be toxic either, can it .. --Dirk Beetstra T C 06:30, 22 August 2006 (UTC)
No, it's not toxic; read all the discussions above. It would still be deadly, however, because you need carbon dioxide to trigger your breathing reflexes, AFAIK. --Kjoonlee 12:37, 22 August 2006 (UTC)
The early space missions used 100% oxygen atmospheres - until both the U.S. and Russia experienced fires in the cabin. Of course, they weren't talking to each other and had to both have deadly accidents before its use was abandoned. Rmhermen 19:02, 22 August 2006 (UTC)
Yeah, you can definitely breathe pure oxygen as long as the pressure isn't too high (see Oxygen toxicity). That stuff about needing carbon dioxide doesn't make sense, because you produce CO2 all the time. —Keenan Pepper 21:05, 22 August 2006 (UTC)

Water toxicity move to Science ref desk--Light current 20:57, 22 August 2006 (UTC)

The CO2 driven breathing reflex is due to the CO2 concentration in your own body, which generates its own CO2. Thus breathing an atmosphere entirely lacking in CO2 would not be a problem in that regard. I am however puzzled by the statement that if oxygen falls below 18.5%, asphyxia results. The normal concentration of oxygen is 21% (by volume) or 23% (by weight) so this seems a rather small diminution, given that people can survive easily enough at altitudes where the atmospheric pressure is half normal, and I thought that the key issue was that for breathing to keep you alive you need the partial pressure of O2 in the air to be higher than the equilibrium partial pressure over a haemoglobin solution, thus the benefit of breathing pure oxygen at low pressure.

[edit] Methane amu of 16.04 or 16.01? The story so far

The saga to date: from the talk page of 68.42.137.160 (talk · contribs)

A link to the edit I have reverted can be found here: link. If you believe this edit should not have been reverted, please contact me. See this link which confirms original text: 16.04 Paleorthid 14:53, 9 September 2006 (UTC)
Whatever I put on methane was true. For example, 1 hydrogen atom has an atomic mass of 1.00. In methane, there are 4 hydrogen atoms. Carbon has an atomic mass of 12.01. So 4.00 (from 4 hydrogen atoms) + 12.01 (from carbon atom)= 16.01. So methane has an atomic mass of 16.01. —Preceding unsigned comment added by 68.42.137.160 (talk)
Thanks for writing your logic here for the change at methane. it might be better to use the talk page at methane to explain such an edit. Despite what you say. The formula weight for methane = 4 H atoms x 1.008 amu + 1 C atom x 12.01 amu = 16.04 amu David D. (Talk) 19:51, 11 September 2006 (UTC)
No, you got it all wrong. There is no such thing as 1/1000 of an atomic mass. 4 H atoms x 1.00 + 1 C atom (12.01)= 16.01 —Preceding unsigned comment added by 68.42.137.160 (talk)
Do you have a reference for this? David D. (Talk) 20:14, 11 September 2006 (UTC)
Sorry to butt in, but David D is in fact correct. Hydrogen is 1.008 amu. With that in consideration, methane's formula weight would be 16.04 amu. --Nishkid64 19:57, 11 September 2006 (UTC)
No, I am correct. There does not seem to be any logic behind the fact that there would be 1/1000 of an atomic mass. So with that, hydrogen has an atomic mass of 1.00 and therefore, methane has a mass of 16.01 —Preceding unsigned comment added by 68.42.137.160 (talk)
Possibly you are confusing it with the atomic number? David D. (Talk) 20:04, 11 September 2006 (UTC)
An amu is just a unit of mass. That doesn't mean that there is no mass lower than it. Why do you think we have moles and stuff? --Nishkid64 20:08, 11 September 2006 (UTC)

You know what, you're right. I apologize. Despite what I did wrong, I do have a suggestion that will help you. You can round 1.008 to 1.01. Plus, the hydrogen atom has 1 proton and 1 electron. That electron can be worth 1/100 of an atomic mass. So 1 hydrogen atom can have an atomic mass of 1.01. So that means methane can have an atomic mass of 16.05.—Preceding unsigned comment added by 68.42.137.160 (talk)

Thank you for going and researching this yourself. With regard to 16.05, I would assume it is better to going with the value used by chemical index's. I have not checked, but I presume they use 16.04. David D. (Talk) 20:37, 11 September 2006 (UTC)
With all due respect David D., I think that you should agree with me. Anthony P.
Does Merck agree with you? :) David D. (Talk) 20:54, 11 September 2006 (UTC)
What do you mean? —Preceding unsigned comment added by 68.42.137.160 (talk)
The Merck index has an extensive amount of data on a massive number of chemicals. What does the Merck index use for the amu of methane? David D. (Talk) 21:09, 11 September 2006 (UTC)

I don't have the Merck index. It's possible, however unlikely that it says what I said. —Preceding unsigned comment added by 68.42.137.160 (talk)

I am assuming that whom ever set up those chemical infoboxes used a source such as the Merck index. That is why i would favour 16.04 since it is likely to be the accepted value by chemists. Original research with respect to rounding etc. is not encouraged. Wikipedias role is to report what is accepted and published. David D. (Talk) 21:17, 11 September 2006 (UTC)
You might be right David D. However, I still recommend that you try my suggestion. You don't have to, but I would greatly appreciate it if you did go with my suggestion. Maybe some chemists do say that 1 hydrogen atom has an atomic mass of 1.01 and that methane has an atomic mass of 16.05. Anthony P.

I'm sorry for vandalizing. I was just thinking methane had an atomic mass of 16.01, because I was thinking hydrogen had an atomic mass of 1.00. Anthony P.

Thanks for the apology. It means a lot. I must apologize to you for biting a newbie. Not my greatest moment. Welcome to WP, and I hope you have a lot more edits in you. Please use edit summaries for all your edits (like: H has mass=1 therefore methane=16.01), then we all can consider and process smoothly. Please register. If you don't get a welcome mesage in short order, contact me and I'll be happy to welcome you. Also, when you leave a message on someone's talk page, please carefully review your changes for the first dozen edits or so, and make sure you didn't inadvertently blank content in the processs. Cheers! Paleorthid
Paleorthid, I want to let you know that I have changed methane's atomic mass back to 16.01, but I wrote a summary why I did so, just like you told me to. Anthony P.
That edit will never get through. You are adding an inaccurate number. It makes no sense to do a rough calculation to get the number when we have an accuarte number in the chemical indexes. If you really want to try and make your case you will need to discuss this on the methane talk page. David D. (Talk) 20:02, 13 September 2006 (UTC)
The chemical substance pages document the compounds as they exist in real life, which means elements are not isotopically pure. You need to use an average mass for each, weighted by their natural isotopic ratio. That means hydrogen isn't "1H" (mass=1), but "natural hydrogen" at about 1.008. DMacks 20:06, 13 September 2006 (UTC)
Hey, this is business between me and Paleorthid. Don't just barge in. Anthony P.
Wikipedia is a community project. Any editor is welcome to work on any page. Given you have edited a page in which I have an interest and are discussing that edit right here, I am part of this discussion. But regardless, anyone is welcome to join any discussion anywhere on Wikipedia in which they have any interest or useful info. That's how it works. DMacks 20:44, 13 September 2006 (UTC)
Look, I have changed the mass of methane, but I wrote a summary. Wikipedia is saying whenever you do an edit, you must right a summary. Paleorthid also suggested it, and that is what I did. So why are you acting like it's a big deal? Anthony P.
My problem isn't the use of the summary, but rather that your change is factually wrong. DMacks 20:57, 13 September 2006 (UTC)
It is wrong and your edit will be reverted everytime. You really should take this to the methane talk page. Wikipedia works through concensus, have you noticed that at present there are multiple editors reverting your change? There is a strong concensus against your edit. Why don't you start up your own user account at User:Anthony P.? That will be more constructive and then people can help show you the ropes. At present you are in a futile cycle and there are rules about not reverting multiple times in the way you are currently editing. See WP:3RR. David D. (Talk) 21:03, 13 September 2006 (UTC)

After this extensive discussion I think it is clear we are being trolled. Is there an Admin around to deal with this? David D. (Talk) 20:22, 13 September 2006 (UTC)

At best, we have a good-faith editor who is stubbornly failing to learn what we're all trying to teach him and who doesn't understand the WP collective-editorship system. It appears that:
  • 16.04 is the calculated answer when one does not make mathematical mistakes (round-off errors) or mis-understand what atomic mass means in this context
  • 16.04 is what Aldrich lists
  • there's no basis remaining for any other value

So 16.04 it is. DMacks 20:42, 13 September 2006 (UTC)

  • silly discussion see Aldrich with 4*1.0079+12.011 (its all about isotopic distribution) you get to 16.043, please ban the troll V8rik 21:39, 13 September 2006 (UTC)

[edit] Farenheit

In the infobox why would we need farenheit? Do scientists use this? And it does not really help the lay reader since they are not in the range that people can relate too. Personally they seem superfluous and I would be in favour of cutting them out. David D. (Talk) 20:05, 6 January 2007 (UTC)

While I'm at it why is the triple point in bars? Can we stick to SI units? David D. (Talk) 20:06, 6 January 2007 (UTC)

Is methane unhealthy for us?

[edit] Graph

I don't get it, in the "total(%/a)" column it adds up 45+55-97=7.19 ??? 71.161.48.4 04:38, 12 May 2007 (UTC)

That does look weird, and I don't know the actual intent of meaning here. However, I do see that the "7.19" value is marked "ppb/a", a different unit than the "total (%/a)" column header, so perhaps it's not really the cummulative or column-total as you infer. DMacks 06:42, 14 May 2007 (UTC)

[edit] What the shit?

Re: the 'Emissions of methane' section

First of all, the data in the table come from Lelieveld in 1998, not Houweling in 1999. Second, they're the highest measurements available, and do not reflect mean consensus at all. Apparently someone doesn't know how to read table 4.2 [5].

Just because the fields are not aligned doesn't mean you as a human being need to forget how to fucking count.

--76.224.78.226 10:28, 28 July 2007 (UTC)

[edit] Is it "heavier" or "lighter" than "air"???

That's what I came to Wikipedia to find out. It seems like it would naturally rise, and all the beautiful charts don't really answer this one simple question. Where are the scientists who want to help the average guy understand the cool stuff? Can anyone chime in? --Torchpratt 11:53, 14 September 2007 (UTC)

According to the article, "the gas at ambient temperature is lighter than air". 70.110.239.244 12:03, 14 September 2007 (UTC)

[edit] 220 tmes as much CO2 in the atmosphere

The intro section says:

"The total warming effect of CH4 is smaller than that of CO2, since there is approximately 220 times as much CO2 in the Earth's atmosphere as methane.[1]"

That is very misleading, or, actually, it's just wrong. The fact that there is so much less CH4 in the atmosphere means that the same amount of methane will mean a larger percentage-wise increase, so it is actually an indication that it will have a greater relative effect. But it's only an indication, it doesn't really say anything. So I removed that bit.
Instead, it makes more sense to compare the effects of the absolute amounts of CO2 increase (so far) and the potential increase in CH4. The article, however, states that "An unknown, but possibly very large quantity of methane is trapped in this form in ocean sediments." If the total amount is unknown, we can't really say much about this. Or does someone maybe know of a reliable source?
For reference, from the IPCC source:

  • CO2 in the atmosphere has risen from 278 to 365 ppm. Radiative forcing: 1.46 Wm-2
  • CH4 in the atmosphere has risen from 0.7 to 1.745 ppm. Radiative forcing: 0.48 Wm-2

(Note that the IPCC table mixes up ppm and ppb - I 'corrected' that.) I wrote a little alternative text, based on the above. DirkvdM 10:04, 14 October 2007 (UTC)

[edit] Methane in the upper atmosphere after breakdown

At the science ref desk (2007 october 13) someone wrote this:

The short lifetime of methane in the upper atmosphere is only partially comforting. When it breaks down you get CO2 and water vapour. Water vapour (at those altitudes) is another gas that's a stronger greenhouse gas than CO2. The amount of these methane clathrate deposits is estimated to be equal to the total amounts of underground natural gas deposits - so even after the stuff decomposes, it would be like putting 500 years worth of CO2 from fossil fuel usage into the upper atmosphere. SteveBaker 15:35, 14 October 2007 (UTC)

Sounds like a useful addition. Anybody know more about this? DirkvdM 17:49, 14 October 2007 (UTC)

[edit] CH4 to C02 is 72 times

It is written - "The Fourth assessment report has updated this number to include indirect effects and states that the relative impact of CH4 to CO2 averaged over 20 years is 72". Yet the link to the IPCC report is dead - and the IPCC website does not have a completed report. Could this link please be updated to underpin this statement. Thanks —Preceding unsigned comment added by Nainishb (talk • contribs) 18:12, 29 October 2007 (UTC)

I have found the proper link, but for some reason am unable to change it. It should be: http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Print_Ch02.pdf Table 2.14, page 212. Could an expert please correct? Thanks —Preceding unsigned comment added by 86.141.240.133 (talk) 09:06, 7 November 2007 (UTC)

Can someone explain how methane's impact can be 72 times CO2 when change in relative forcing of CO2 = 365-278=93, and change in relative forcing of CH4 = 1.745-0.7=1.045 multiplied by 72 = 75.24... how can we say that CH4 is 1/3 the radiative forcing of CO2? shouldn't it be 81%??? Jacksatan (talk) 21:54, 19 March 2008 (UTC)
I've updated the page, which was garbled. THere was no discrepancy. 72 is the GWP, not the radiative impact William M. Connolley (talk) 23:42, 19 March 2008 (UTC)

[edit] Unconfirmed Jenkem constituent

Side effects from inhaling methane have begun to creep into drug culture, starting with street youth in Africa. See the article on Jenkem for details.

I have removed the above from the health effects section. Jenkem is an unidentfied psychoactive compound created from fermenting sewage. It's inappropriate to assert that methane has an active role in this effect. That is at best a speculative statement. __meco 23:06, 13 November 2007 (UTC)

[edit] Cosmic ray ?

It is said in this part Methane#Removal_processes that "The major removal mechanism of methane from the atmosphere is by reaction with the hydroxyl radical (·OH), which may be produced when a cosmic ray strikes a molecule of water vapor" No, not a cosmic ray, merely ordinary ultraviolet radiation, often symbolized with "hν", as you can find in the Radical (chemistry) entry. I correct the article accordingly.--Environnement2100 (talk) 07:40, 7 December 2007 (UTC)

Not exactly. The UV radiation cleaves ozone, and the resulting oxygen atom reacts with water vapor to produce hydroxyl.[6][7] --Itub (talk) 09:53, 10 December 2007 (UTC)

[edit] Methane is Toxic

Meth is toxic. In the main article it said it isn't. That is not true. It causes dizziness, headaches, and maybe even death. —Preceding unsigned comment added by Kmdancer (talk • contribs)


[edit] Explosivity range

I am not a chemist or scientist, so maybe this explains why the statement, 'As a gas it is flammable only over a narrow range of concentrations (5–15%) in air.' in the section 'Properties' is unclear to me. Does this say that methane is flammable only if it is in a concentration of 5-15%; or is it saying that it must exceed (over) the range of 5-15%? Maybe someone could clarify this in the article.

--Marcos (talk) 15:15, 1 January 2008 (UTC)

I confirm methane is only flammable within the said range of 5-15 %. All gases have a range, so that is why it is (and should be) introduced this way, quite standard.--Environnement2100 (talk) 18:20, 1 January 2008 (UTC)

[edit] Take that profanity off this page

I can't seem to get the F-word off this article.AlexNebraska (talk) 19:06, 20 February 2008 (UTC)

[edit] Extrasolar methane

May be of interest - methane found in another solar system: Talk:Extrasolar_planet#Another_milestone_.3F.--Piotr Konieczny aka Prokonsul Piotrus| talk 19:03, 20 March 2008 (UTC)

Thanks, it seems to be in this article now. -- SEWilco (talk) 04:08, 21 March 2008 (UTC)

[edit] Heat of combustion value

In section 2.1 Fuel, the heat of combustion is given as both 802 kJ/mole and 902 kJ/mole. Which is it? —Preceding unsigned comment added by Redbelly98 (talk • contribs) 01:11, 31 March 2008 (UTC)

Neither; it's about 890 kJ/mol.[8] --Itub (talk) 12:55, 1 April 2008 (UTC)