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Talk:Methane: Difference between revisions

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Archives

Archive 1

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)[reply]

@Potosino: Yes, burning methane into carbon dioxide reduces the resulting greenhouse effect compared to simply releasing it into the atmosphere. This is why some green projects include capturing methane from sewage treatment plants or dairy farms and burning it to power the facility. The difference is mentioned on Global warming potential#Values; I added a note to this article. -- Beland (talk) 02:57, 21 June 2024 (UTC)[reply]

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

09:59, 7 October 2003‎ 24.192.17.162 

— Preceding unsigned comment added by 24.192.17.162 (talk • contribs) 09:59, 7 October 2003 (UTC)[reply]

I'm sure it's not the most energy-efficient way to get methane, but it would be worthwhile to add some mention of methane capture technologies to this article. Example sources:

• Removing methane from the atmosphere
• Capturing methane from the air would slow global warming. Can it be done?
• Practical constraints on atmospheric methane removal

-- Beland (talk) 06:17, 21 June 2024 (UTC)[reply]

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))

This interesting question is still unanswered. -- Beland (talk) 03:19, 21 June 2024 (UTC)[reply]

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) — Preceding unsigned comment added by 212.72.21.122 (talk • contribs) 05:52, 28 August 2005 (UTC)[reply]

That sort of information is available from this NIST site, but it appears to depend on temperature and pressure, so isn't particularly suitable for inclusion in this article. -- Beland (talk) 06:23, 21 June 2024 (UTC)[reply]

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)[reply]

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

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)[reply]

Rice production is now listed under "Biological" sources. -- Beland (talk) 06:24, 21 June 2024 (UTC)[reply]

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)[reply]

Readers can click through to see the full-size version; 600px is a pretty big default. -- Beland (talk) 06:25, 21 June 2024 (UTC)[reply]

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)[reply]

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)[reply]

Is methane unhealthy for us? — Preceding unsigned comment added by 24.211.54.192 (talk • contribs) 18:12, 7 February 2007 (UTC)[reply]

This is now covered in the article. -- Beland (talk) 06:28, 21 June 2024 (UTC)[reply]

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)[reply]

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)[reply]

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 [2].

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)[reply]

Why has noone mentioned cows farting? —Preceding unsigned comment added by 78.80.16.57 (talk) 13:30, 10 December 2008 (UTC)[reply]

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)[reply]

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

Air is mostly made of diatomic nitrogen (N2) and diatomic oxygen (O2). Methane is CH4. The mass of an N2 molecula is about 28 amu; the mass of O2 is about 32 amu; the mass of CH4 is about 16 amu. So, methane is "lighter than air". As for example of a gas which is "heavier than air" (hence, it can accumulate on the bottom of a pit effectively displacing air), CO2 has an atomic mass of 44. —Preceding unsigned comment added by 151.20.41.46 (talk) 12:27, 31 May 2009 (UTC)[reply]

The intro section says:

"The total warming effect of CH
₄ is smaller than that of CO
₂, since there is approximately 220 times as much CO
₂ 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)[reply]

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)[reply]

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

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

Not exactly. The UV radiation cleaves ozone, and the resulting oxygen atom reacts with water vapor to produce hydroxyl.[3][4] --Itub (talk) 09:53, 10 December 2007 (UTC)[reply]

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)

Only in strong doses, by that logic oxygen is toxic —Preceding unsigned comment added by 121.73.44.28 (talk) 09:55, 25 February 2009 (UTC)[reply]

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)[reply]

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)[reply]

Methane is explosive between 5-15% concentration in the presence of oxygen, not flammable.<http://www.engineeringtoolbox.com/explosive-concentration-limits-d_423.html> Editors please up date main article this is dangerous. Ecogreg2009 (talk) 22:36, 16 February 2009 (UTC)[reply]

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

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)[reply]

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

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)[reply]

Neither; it's about 890 kJ/mol.[5] --Itub (talk) 12:55, 1 April 2008 (UTC)[reply]

I would post this in the difluoromethane section, but there isn't any discussion there so I'd never get my question answered. It has a chance here.

I burned some difluoromethane (canned air keyboard cleaner), and the product smelled just like hydrochloric acid. Could the combustion of CF2H2 perhaps form CO2 and HF? I would imagine that HF has a similar odor to HCl, both being halogen acids. —Preceding unsigned comment added by 214.13.149.10 (talk) 15:13, 2 July 2008 (UTC)[reply]

There is an error in the heat of combustion of methane - the quoted value is 809 kJ mol^{-1} - the 9 and the 0 are reversed. —Preceding unsigned comment added by 81.96.174.16 (talk) 20:48, 17 September 2008 (UTC)[reply]

Done. --Itub (talk) 08:49, 18 September 2008 (UTC)[reply]

Can I suggest the following changes.

a) the title Sources be changed to Sources and Sinks

b) the following paragraph be entered at the beginning of the section:

The balance between sources and sinks is not yet fully understood. The IPCC working group 1 stated in chapter 2 of the fourth assessment report that there are "large uncertainties in the current bottom-up estimates of components of the global source" and the balance between sources and sinks is not yet well known. The most important sink in the methane cycle is the hydroxyl radical, which is produced photochemically in the atmosphere. The production of this radical is not understood and has a large affect on atmospheric concentrations. This uncertainty is exemplified by observations that have shown between the year 2000 and 2006 increases in atmospheric concentration of methane ceased without reduction in anthropogenic sources, showing that methane accounting does not accurately predict methane observations.

(taken from IPCC AR4 WG1 CH2 pg 142)

c) a more up to date estimate of sources and sinks be found. As has been stated in point (b) this is an evolving space. I concede that the discovery of methane from living plants needs time for the dust to settle before it is added to the table but surely anthropogenic sources have changed in the last 10 years?

Thanks —Preceding unsigned comment added by 202.50.184.138 (talk) 03:30, 19 February 2009 (UTC)[reply]

I like that theme, but it needs to be properly referenced.Andrewjlockley (talk) 23:19, 17 March 2009 (UTC)[reply]

They MAY produce a higher output in humans, however humans are not Rumenants so direct methane output from humans is not comparable. Bogman bass (talk) 18:26, 29 January 2020 (UTC)[reply]

Why does methane have a higher boiling point than oxygen or nitrogen, even though it is not polar and half as massive? This is not even mentioned in the article. —Preceding unsigned comment added by 85.232.196.151 (talk) 12:22, 21 August 2009 (UTC)[reply]

• I'm not sure if this is a reason, but although methane has total dipole moment=0, its C-H bonds do have a small polarity (about 3%). N-N and O-O bonds in their molecules are totaly neutral. Perhaps this fact plays a role...

--Vchorozopoulos (talk) 20:32, 22 October 2009 (UTC)[reply]

As both (di)oxygen and nitrogen have a double bond and p-orbitals, you may suppose their outer surface is slightly more electronegative than the s-based methane, hence more repulsion. If you start into this kind of info, the article is going to be very interesting, but very long.--Environnement2100 (talk) 22:29, 22 October 2009 (UTC)[reply]

Except dioxygen does not have a double bond in its ground state. DMacks (talk) 02:00, 23 October 2009 (UTC)[reply]

N₂, O₂ and CH₄ are all non-polar molecules. The only forces holding these molecules together and keeping them liquid are London dispersion forces. These forces are stronger between molecules that are more polarizable - so the reason that CH₄ remains at liquid at temperatures where N₂ and O₂ are gases is that methane is more polarisable than dinitrogen or dioxygen.

Ben (talk) 22:26, 22 October 2009 (UTC)[reply]

• I think the article is a needed that kind of info and not only. It doesn't matter if it'll become large. Someone may need or simply want it. That's why we are here: To provide any correct info we have and explain everything if possible.

--Vchorozopoulos (talk) 22:34, 28 October 2009 (UTC)[reply]

Vegans and vegetarians argue that we need to stop breeding cows and stop eating all meat because meat production is killing the planet. This is based on the claim that methane is 20 times worse than CO2 (GWP of 22). Though they ignore the shorter life span of CH4 against CO2. Methane sources listed across different articles seem to be wetlands, padi fields, tropical area, rubbish dumps, volcanoes, the sea (ocean sediments), peat bogs, coal mines, ponds, rivers, any rotting vegetation and grass eating animals - cows, buffalos and sheep. Am I right that foods such as greens and pulses cause a higher methane output in humans? Whereas, protein based foods (meat) don’t. If so, surely a vegetarian diet is worse for the environment?---- —Preceding unsigned comment added by Chrstoff (talk • contribs) 22:35, 12 September 2009 (UTC)[reply]

• I think there is a problem with uaing their symbol, isn't it? This way ${\displaystyle ^{\cdot }}$ we get a small dot and this way ${\displaystyle ^{\bullet }}$ a large one. Ia there a normal one?
• Anyway in this article the dot appears too low. Why you don't use the ^ to put higher?

--Vchorozopoulos (talk) 02:10, 22 October 2009 (UTC)[reply]

If Methane was not discovered until 1776, how do we have data for its concentration in the atmosphere from 26 years earlier? —Preceding unsigned comment added by 118.236.177.222 (talk) 10:53, 9 December 2009 (UTC)[reply]

Air from 1750 was trapped in ice and analyzed much later. Materialscientist (talk) 11:08, 9 December 2009 (UTC)[reply]

People of the IPCC tell complete nonsense.

The abundance of methane in the Earth's atmosphere in 1998 was 1745 parts per billion, up from 700 ppb in 1750. Methane can trap about 20 times the heat of CO2. In the same time period, CO2 increased from 278 to 365 parts per million.

That means: CO2 rised by 365 - 278 = 87 ppm, while methane by 1.745 - 0.7 = 1.045 ppm. The IPCC people say, that the same mass of methane makes 25 times the effekt of carbon dioxide, but one molecule methane has only about one third of the mass. There are about 87 times less molecules methane and hence about 250 times less mass. Even if, one ton of methane would be 25 times more dangerous than one ton of carbon dioxide, still the effect would be not more than 10 percent compared to CO2. --RainbowB (talk) 20:24, 23 January 2010 (UTC)[reply]

If you have questions (and clearly you do) about a topic that (clearly) you don't understand well, it is a good idea not to assume that all the people that do understand it are fools who have made crass errors that even Joe Public can spot.

So, there are lots of things wrong with what you've said. The easy bit is that these concentrations are in ppmv, the v standing for volume, not mass (hope I've got that right or I'll look silly). Another part is that you can't claim radiative forcing in isolation, since they overlap. Another part is that methane decays to CO2 and stratospheric water. The harder bit is that radiative forcing is not proportional to concentration. There are, roughly, 3 regimes, going from linear to (I think) sqrt to logarithmic as concentration increases. CO2 is in the linear range. I forget for methane, but it might be linear William M. Connolley (talk) 21:21, 23 January 2010 (UTC)[reply]

Due to Avogadro's law one ppm, ppmv to be precise, means one molecule of one million. The atomic weight of methane is 16 compared to 44 of CO2. --RainbowB (talk) 22:04, 23 January 2010 (UTC)[reply]

The carbon bond angle in methane is only approximately 109.5 degrees. The exact angle can be calculated using simple trigonometry, and is in fact 180 - arccos(1/3), or 109.47122... —Preceding unsigned comment added by Wissnergross (talk • contribs) 14:58, 10 August 2010 (UTC)[reply]

Can someone go ahead and add the electronegativity of Methane? I know that it is 0.35. Thanks! :D Infinity Warrior Dazing off into the cosmic paradise... 19:21, 20 November 2011 (UTC)[reply]

Do you have a source for this value? We need a specific citation (bibliographic entry) to verify this information. DMacks (talk) 19:40, 20 November 2011 (UTC)[reply]

Other than the electronegativity of both Hydrogen (2.20) and Carbon (2.55), and a few Yahoo! Answers, plus the math on how to solve for electronegativity on Wikihow, not entirely. I can post a link to all the sources, but compiled into one, I can't seem to find outside of Yahoo! Answers. — Preceding unsigned comment added by Infinity Warrior (talk • contribs) 22:40, 20 November 2011 (UTC)[reply]

The recent revert gave an insufficient explanation other than "conformity". Before reverting again, please explain this "conformity", so I may refer to it in future edits. –Temporal User (Talk) 11:34, 7 December 2011 (UTC)[reply]

There is a usual method of entering and displaying data in the chembox, the items that I reverted did not make an apparent improvent by contrasting the usual method. Plasmic Physics (talk) 06:09, 8 December 2011 (UTC)[reply]

In addition, it was decided by the Chemistry Project that unless particularly notable, no value outside of STP be included in the chembox, and in the case that such a value is indeed notable, it must be discussed first. Otherwise, if the value under STP is not available, then an appropriate value is chosen closest to STP conditions. Plasmic Physics (talk) 06:19, 8 December 2011 (UTC)[reply]

Could you please refer me to documentation/discussion of the "usual" method of chembox data entry?

The original value for density was not at STP, and I couldn't find STP values with my available sources. So I provided two that were close. –Temporal User (Talk) 08:07, 8 December 2011 (UTC)[reply]

There is no documented usual method, as it is not set in stone. It is simply a fluid collection of guidelines approved and supported by the Chemistry Project, to indroduce a form of consistance.

Why is there a need for a second value, if the first value is at STP?

Why do see a reason to not use the BoilingPtKL/H and MeltingPtKL/H fields? Plasmic Physics (talk) 09:52, 8 December 2011 (UTC)[reply]

If there are no centralized guidelines, there should at least be documented discussions on the specific aspects of the chembox we're discussing. Could you please refer me to those?

The first value is not at STP (i.e. 100 kPa). Although it's close at 1 atm, the distinction should be noted.

If you had read my comment you deleted, when the template was using boilingptk, it truncated the negative sign from the number of the F temperature, so the F temperature appeared as a positive temperature on a second line. –Temporal User (Talk) 00:59, 10 December 2011 (UTC)[reply]

No such acception is made anywhere else when truncation occurs, and is unnessecary. Distinction is moot, as the value of 1 atm has one significant figure, when converted into kPa, as result of 100 kPa is obtained also with one significant figure; unless the pressure in atmospheres is given with at least three significant figures, there is no point in making a distinction. It would be difficult to track down the exact discussion surrounding this topic, as it is hidden is months' worth of archived deliberation. Plasmic Physics (talk) 01:45, 10 December 2011 (UTC)[reply]

Would it be accurate to say that you no longer have an interest in argueing your case? If so I will revert at the end of 24 hours. Plasmic Physics (talk) 02:17, 31 December 2011 (UTC)[reply]

Is there an article related to Methane in Earth's atmosphere?99.181.143.133 (talk) 08:29, 1 January 2012 (UTC)[reply]

The closest I've seen is Atmospheric chemistry. 99.181.132.130 (talk) 05:34, 22 January 2012 (UTC)[reply]

That article is weak on the topic, as is Atmosphere of Earth. 99.19.44.50 (talk) 00:32, 3 February 2012 (UTC)[reply]

See Atmospheric methane. 99.181.131.248 (talk) 06:04, 19 March 2012 (UTC)[reply]

In the section http://en.wikipedia.org/wiki/Methane#Fuel the fourth sentence in the paragraph, i.e. the statement: "In many cities, methane is piped into homes for domestic heating and cooking purposes" is incomplete/inaccurate/insufficient. It implies that residential methane piping is restricted to cities. In fact, many large suburban areas also feature piped 'natural gas'. Also, the implication disregards piped CH4 for industrial and commercial uses. — Preceding unsigned comment added by 74.67.225.15 (talk) 12:01, 25 January 2012 (UTC)[reply]

I think the value given here (-187C) may be wrong. Many other sources (even including Wikipedia's Alkane page) give a melting point of -183C, considerably higher than the -187C given here. the Open Melting Point Data Explorer shows values between -182C and -183C, and writes off the single -187 measurement (Streng, 1971) as an outlier. — Preceding unsigned comment added by 121.98.141.28 (talk) 02:01, 8 February 2012 (UTC)[reply]

-182.47 C according to Lide, D. R., ed. (2005). CRC Handbook of Chemistry and Physics (86th ed.). Boca Raton (FL): CRC Press. ISBN 0-8493-0486-5.. Corrected, thanks. Materialscientist (talk) 02:04, 8 February 2012 (UTC)[reply]

There seems to be an edit war today over the insertion by 99.109.126.63 of claims that dinosaur flatulence may have caused global warming in the past. The edit summaries this week include 3 accusations by another editor that 99.109.126.63 has lied about source article content in the past. I think it would be more appropriate to say that s/he has been mistaken in the past. Also, even if an editor has been mistaken in the past, new evidence by the same editor should at least be considered in most cases.

While I have not followed the entire thread, the latest source given by 99.109.126.63 is an article in the London Daily Telegraph, which is free-access (now at least) and does seem at first reading to justify the description given by 99.109.126.63. Perhaps it would be better to prefix the sentence with "According to the Daily Telegraph, ...", rather than exclude the source entirely.

Also the Daily Telegraph does provide the journal title and author names, which enabled me to find the original article on Google in about 3 minutes here. This is open access also and can be included as a second source in the article. (I would keep the Telegraph article as first source since it is easier to read.) Dirac66 (talk) 15:31, 8 May 2012 (UTC)[reply]

Various other secondary and tertiary sources seem to be reporting on the reporting as well, and some are especially critical of the "causes global warming" lay-language analysis in the earlier secondary reports. For example, Pharyngula (blog) raised concerns of Conservative/anti-global-warming spin.[6] Definitely important to have a diversity of secondary sources here, or at least not overstating the case (avoiding loaded language from a single secondary source that is not known for its own neutrality). DMacks (talk) 15:43, 8 May 2012 (UTC)[reply]

Yes, I agree it would be best to have a balanced (NPOV) presentation with a diversity of secondary sources. For such a controversial topic, this is certainly preferable to just deleting the one that presents the questionable view. Dirac66 (talk) 16:11, 8 May 2012 (UTC)[reply]

It shouldn't be in the article. Its too new, and untested, and speculative (in its connection to GW) William M. Connolley (talk) 17:02, 8 May 2012 (UTC)[reply]

"In 2010, methane levels in the Arctic were measured at 1850 nmol/mol, a level over twice as high as at any time in the previous 400,000 years."

It's an inflammatory exaggeration. 1850 nmol/mol is not "twice as high" as the level in 2008, and 2008 is included in the previous 400,000 years. If you want to claim that 1850 nmol/mol is twice as high as the level at some other time, pick the latest year in which that is true and cite that. 68.109.89.36 (talk)musant —Preceding undated comment added 14:26, 8 August 2012 (UTC)[reply]

I have moved this new section to the end of the talk page. Would it be more accurate to say "a level over twice as high than at any time in the 400,000 years previous to 1750"? I do agree with William M. Connolley (in an edit summary today) that "doubled over the past 400,000 years" is misleading, because it incorrectly suggests a gradual increase over 400,000 years. Dirac66 (talk) 15:13, 8 August 2012 (UTC)[reply]

Something like "pre-1750" or "prior to the industrial revolution" would be accurate, I think. "pre-industrial" might be better - we're not trying to give an accurate date, just an indication that we've more than doubled the conc. File:Vostok 420ky 4curves insolation.jpg shows that pre-industrial max was lt 800 William M. Connolley (talk) 16:05, 8 August 2012 (UTC)[reply]

OK, I have changed it to "prior to the industrial revolution". "Pre-industrial" would be more concise but doesn't make a very good sentence. And perhaps the Vostok 420ky figure should also be included as a source. Dirac66 (talk) 16:21, 8 August 2012 (UTC)[reply]

The indexes cited from IPCC AR5 are not consistent, the index for GWP₁₀₀ is is 86x CO₂ which is one that includes short term feedbacks, which more typically used than without short term feedbacks, but the GWP₂₀ number is without STFs i.e. 28 to be consistent should be 34x CO₂. Also the 20% of anthropogenic warming including short term feedbacks (the warming caused by 'downstream' decay products stratospheric water vapour (2.6%), ground level ozone (9.1%) &CO₂ (0.7%)) is more like 37%, and not including is 21%. This needs to be fixed by someone. — Preceding unsigned comment added by WideEyedPupil (talk • contribs) 02:33, 1 September 2019 (UTC)[reply]

Why is the section on Extraterrestrial methane placed in an Appendix after the References, and with its own separate list of References? This means that the first list of references breaks up the article, so that some readers may miss the extraterrestrial section. Most Wikipedia articles place the sections sequentially, without reference lists in the middle.

The only reason I can see is that this appendix is poorly written and reads more like a list than like an article. But the solution for that is to rewrite the section properly, not to separate it from the rest of the article.

I suggest we rewrite the Appendix as a regular section of the article, and place a single list of references at the end. Unless others think that what is outside the planet must be outside the article :-)). Dirac66 (talk) 19:16, 29 September 2012 (UTC)[reply]

I see that this has been fixed today. Thank you, Lchappell. Dirac66 (talk) 21:21, 12 November 2012 (UTC)[reply]

we are producing methane gas mixture by Pyrolysis of the rubber scrap, is that possible we can store that gas and reuse it for further heating the boiler or can we directly use it into a gas generator. — Preceding unsigned comment added by 106.206.84.93 (talk) 13:31, 13 March 2013 (UTC)[reply]

Does anybody know who first:

1. Identified methane?
2. Identified its composition?
3. Named methane? And why?
4. Identified each of methane's various sources (natural gas, biological...)?
5. Liquefied methane?
6. Synthesized methane?
7. Produced methane in industrial quantities?
8. Put methane to industrial use?

Thanks! Lockesdonkey (talk) 18:55, 11 May 2013 (UTC)[reply]

In the "Atmospheric methane" section there are two statements of "net lifetime" in the atmosphere:

"It has a net lifetime of about 10 years" "a net lifetime of 8.4 years"

Which is it? Granted, 8.4 is approximately 10 but why use two different values? Can anyone clarify, and make these consistent? — Preceding unsigned comment added by 68.145.215.129 (talk) 03:14, 29 November 2013 (UTC)[reply]

In the section on liquid methane rocket fuel there is a statement about NASA's Curiosity rover not finding any methane in the atmosphere of Mars. This statement is misleading because NASA is looking for methane on Mars as a possible biosignature of life, not as a source of fuel. Methane can be produced on Mars using carbon dioxide from the atmosphere and a small amount of hydrogen that is either brought to Mars or extracted from water sources found on Mars. The misleading statement cites an article at: http://www.nasa.gov/mission_pages/msl/news/msl20130919.html It should be noted that if you search the article neither the word "rocket" or the word "fuel" are present anywhere. Furthermore, Wikipedia's entry on methane already contains a section on extraterrestrial methane that covers Mars extensively. That section covers the fact that Curiosity found less than 5ppb of methane in the atmosphere and gives four different citations of that fact. The misleading statement adds no information to the methane article and could be detrimental to readers' understanding of Mars exploration. Why do people keep undoing my removal of this statement? — Preceding unsigned comment added by Scott247 (talk • contribs) 18:30, 2 July 2014 (UTC)[reply]

The context in the previous few sentences clearly talks about harvesting already-present methane for fuel purposes, and evidence that it does not seem to exist (in sufficient amount) is a pretty good counterpoint to that idea. Data don't care why you were originally making the measurements. The statement could be modified to include those details ("NASA's whatever-probe, looking for the methane signature of life, found only 5 ppb[that-cite], which is well below the whatever-amount that would be viable for harvesting as fuel[some-other-cite]."). Your proposal for manufacturing methane from other present materials is a different idea...one that could also be stated, with cites supporting both the process and the availability of sufficient starting materials. DMacks (talk) 19:12, 2 July 2014 (UTC)[reply]

Yes, the previous few sentences talk about harvesting. Then a misleading statement follows which cites an article that does NOT talk about harvesting. This isn't about the data, this is about intention. The citation and data do not provide evidence that anyone intended to harvest methane on Mars. It's like stating that humans need water to live and then citing a study that found the oceans are undrinkable because they contain salt. The positioning of the statement carries the implication that people were planning to drink ocean water. Scott247 (talk) 19:41, 2 July 2014 (UTC)[reply]

To carry your analogy further, would a sentence like "the existing oceans, containing the vast majority of the water present, are undrinkable because they are salty, but fresh water is available from other sources" be reasonable? It seems like it addresses both ideas: if the topic is specifically fresh (drinkable) water, it's notable that the most obvious source of "water" is not of this type but that we do have a niche for survival via alternate sources. DMacks (talk) 19:53, 2 July 2014 (UTC)[reply]

I'm not trying to add statements to the article, I'm trying to remove one that's poorly positioned. There are equivalent statements in the Extraterrestrial methane section of the article and an explanation of methane production is already given in the Production section of the article. Are you suggesting that I should be elaborating on a redundant statement? Scott247 (talk) 20:43, 2 July 2014 (UTC)[reply]

This article contains a one-sentence paragraph asserting that methane depletes ozone. I would encourage comments on whether it should be changed. This appears to have been part of the article for a long time.

Methane also affects the degradation of the ozone layer.

It does not appear to be manifestly correct and not directly supported in the references given. (It is almost true as written but needs a couple of sentences to be more understandable.) I hesitate to edit this as I am not an atmospheric chemist though I do believe I understand the chemistry/physics. My reasoning is as follows.

First, this is the second paragraph of the section on Atmospheric methane, referencing the main article Atmospheric methane. In the Atmospheric methane article, I find no references to ozone depletion and only one occurrence of the word ozone. The assertion therefore does not seem to be derived from the current version of the parent article.

Second, a reference is provided to an article "Ozon," on an archived website page. Ozon – wpływ na życie człowieka, Ozonowanie/Ewa Sroka, Group: Freony i inne związki, Reakcje rozkładu ozonu. ozonowanie.com This is not in my native language but reviewing what I can deduce from the archived version gives no connection between methane and ozone. Perhaps a native speaker/reader could deduce more.

Third, another reference is provided to a reputable and readable web source. Fahey, D.W. (2002) Twenty Questions And Answers About The Ozone Layer , UNEP, pp. 12, 34, 38 On page 12 of the above reference is the only relevant assertion that methane reactions form "water vapor and reactive hydrogen" which are relevant to the "balance of stratospheric ozone." Methane is described as one of two examples of "Other gases" of importance with nitrous oxide being the second.

The statement in Fahey reference above means that the sentence in question is not actually wrong, but even the Fahey reference says the impact of methane (on the indicated pages 34 and 38) is not significant. More precisely, the chemistry of ozone is overwhelmingly influenced by halogen containing compounds and the importance of methane is a result of its contribution to global warming.

OK, I know this is getting long, but a more informative statement might be that atmospheric methane has a minor role in the chemistry of the ozone layer, but the ozone layer is significantly influenced by atmospheric temperature in the polar regions and thus methane's role in global warming is potentially very important to the ozone hole. The Fahey reference makes this clear.

It seems then that the main point is perhaps that climate change/global warming may seriously damage the ozone layer and that concept does not really come across in the sentence in the current form.

If someone (maybe me) changes this article, then it may have consequences for related articles. Ozone layer Ozone depletion Ozone depletion and climate change Atmospheric methane The main articles on Climate change and Global warming are also relevant but perhaps this issue of methane and the ozone layer are too technical for these Wikipedia entries. Thanks for any feedback. Mike (talk) 20:40, 13 December 2015 (UTC)[reply]

I agree. I've chopped out that bit, and some more. Of that bit: it seems sufficiently marginal that it doesn't belong here. It might belong in Atmospheric methane, perhaps. Of the other bits chopped: there's a main article, Atmospheric methane, so we shouldn't repeat much here William M. Connolley (talk) 20:54, 13 December 2015 (UTC)[reply]

• Related science Wetter Upper Atmosphere May Delay Global Ozone Recovery (2001) or et al 2013 prokaryotes (talk) 21:07, 13 December 2015 (UTC)[reply]

Please don't bloat this page. There's an entire article about atmospheric methane. The ozone stuff belongs there, perhaps, but not here William M. Connolley (talk) 21:56, 13 December 2015 (UTC)[reply]

You also removed a study on Antarctica's methane, and reverted now back to a version which also removed my other edits. If you remove something, move the content to the correct article, if you revert, only revert so that you do not remove other contributions. I leave it now to other editors to revert your brutal remove every single edit revisions. Moved the ozone layer stuff for you to the AM page.prokaryotes (talk) 05:57, 14 December 2015 (UTC)[reply]

Yes, I removed the also marginal Antarctica stuff. For the reasons I gave. You should have realised you were re-adding material to the wrong page, because I'd already explained that William M. Connolley (talk) 08:15, 14 December 2015 (UTC)[reply]

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47 citations support the discussion of methane on other planets etc. Although well intentioned, that number of references is undue weight. I plan to trim that list to a few citations. We also do not need to enumerate every non-terrestrial source of this stuff.--Smokefoot (talk) 14:42, 25 March 2018 (UTC)[reply]

The section on Mars starting at "Methane has been proposed as a possible rocket propellant..." discusses generating Methane on Mars for rocket fuel. Unfortunately, it neglects to mention Oxygen, also needed for the fuel, unless you come up with a different oxidant. (We're not on earth anymore!) From what I've seen, oxidizer tanks on liquid fuel rockets tend to be larger than for the fuel, so I'd guess that generating the oxidizer on mars would be a bigger problem. OsamaBinLogin (talk) 01:42, 16 March 2024 (UTC)[reply]

The "Generation" section gives an incomplete and confusing description of the geologic production of methane in addition to a very short biological route explanation, which could be expanded. The "Occurrence" section includes information on clathrate hydrates, and is largely based on a news article discussing a newly discovered source of methane in the Arctic and the section doesn't address the other prevalent sources. Finally, there's a one sentence description of AOM, which could be expanded and moved to the biological route subsection under generation; the biological route subsection could then be split into methanogenesis and methanotrophy. I plan update these sections for my wikipedia project. --Ajohnson439 (talk) 04:08, 16 February 2019 (UTC)[reply]

The VESPR diagram on the fact sheet seems to be misleading — as a tetrahedral represented in the manner it is currently would seem to indicate that here is a difference in angle between the four hydrogens (more specificly, the "top" hydrogen with the rest) whereas, realistically, they exhibit uniformally 190º angle. See this image (0 lone pair and steric number 4) for an example of how one may represent it. --jemoka (talk) 9:41, 14 October 2019 (PST)

In no particular order:

Thiel, Volker (2018), Wilkes, Heinz, ed., "Methane carbon cycling in the past: insights from hydrocarbon and lipid biomarkers", Hydrocarbons, Oils and Lipids: Diversity, Origin, Chemistry and Fate, Handbook of Hydrocarbon and Lipid Microbiology, Springer International Publishing, pp. 1–30, doi:10.1007/978-3-319-54529-5_6-1, ISBN 9783319545295, https://doi.org/10.1007/978-3-319-54529-5_6-1.

Reeburgh, William S. (2007). “Oceanic methane biogeochemistry”. Chemical Reviews. 107 (2): 486-513. https://doi.org/10.1021/cr050362v.

Etiope, Giuseppe; Lollar, Barbara Sherwood (2013). "Abiotic methane on Earth". Reviews of Geophysics. 51 (2): 276-99. http://dx.doi.org/10.1002/rog.20011.

Whiticar, M. J. (1999). “Carbon and hydrogen isotope systematics of bacterial formation and oxidation of methane". Chemical Geology. 161: 291-314. https://doi.org/10.1016/S0009-2541(99)00092-3.

Serrano-Silva, N.; Sarria-Guzmán, Y.; Dendooven, L.; Luna-Guido, M. (2014). “Methanogenesis and methanotrophy in soil: a review”. Pedosphere. 24: 291-307. http://dx.doi.org/10.1016/S1002-0160(14)60016-3.

Sirohi, S. K.; Pandey, N.; Singh, B.; Puniya, A. K. (2010). “Rumen methanogens: a review”. Indian J Microbiol. 50 (3): 253-262. https://doi.org/10.1007/s12088-010-0061-6.

Knittel, K.; Wegener, G.; Boetius, A. (2019), McGenity, Terry J., ed., “Anaerobic Methane Oxidizers”, Microbial Communities Utilizing Hydrocarbons and Lipids: Members, Metagenomics and Ecophysiology, Handbook of Hydrocarbon and Lipid Microbiology, Springer International Publishing, pp. 1-21. https://doi.org/10.1007/978-3-319-60063-5_7-1.

Bohrmann, Gerhard; Torres, Marta E. (2006), Schulz, Horst D.; Zabel, Matthias, eds., “Gas Hydrates in Marine Sediments”, Marine Geochemistry, Springer Berlin Heidelberg, pp. 481-512, https://doi.org/10.1007/3-540-32144-6_14.

Dean, J. F.et al.(2018). “Methane feedbacks to the global climate system in a warmer world”. Reviews of Geophysics. 56: 207-250. https://doi.org/10.1002/2017RG000559.

Moore, T. A. (2012). “Coalbed methane: A review”. International Journal of Coal Geology. 101: 36-81, http://dx.doi.org/10.1016/j.coal.2012.05.011.

--Ajohnson439 (talk) 22:53, 22 February 2019 (UTC)[reply]

Superb references. Thank you for your good taste. It might be worthwhile using these references in subsidiary articles, which might be in greater need of your help. Another action that I sometimes take when armed with strong secondary and tertiary references is that I replace primary references, often en masse, unless they are of historic significance. You do the readers a favor by upgrading references vs just putting more on the heap. When in doubt or if worried about removal of references, you can put the removals on the (this) talk page.--Smokefoot (talk) 23:41, 22 February 2019 (UTC)[reply]

Thank you for the nice comments and advice, Smokefoot. I've added 10 refs only (for the required minimum for a PhD level Biogeochem course project). There may be superfluous references for a couple of sentences. I tried to choose appropriate refs, but am still unsure how the public is supposed to be able to access scientific journal articles that are not open access. Do we typically want to avoid these types of articles? Your help in minimizing refs at this point would be great. Ajohnson439 (talk) 14:57, 11 April 2019 (UTC)[reply]

Re I "am still unsure how the public is supposed to be able to access scientific journal articles that are not open access." That is an important question. Several answers: (1) the most authoritative references are the best, regardless of accessibility since we are aiming for trust/reliability, (2) some scholars can access them, (3) slowly but surely journals are becoming more accessible, ((4) not many readers actually want to read them anyway!). --Smokefoot (talk) 22:42, 11 April 2019 (UTC)[reply]

The figure in sub section Atmospheric methane seems to be inconsistent with this statement in the same sub section:

"From 2015 to 2019 sharp rises in levels of atmospheric methane have been recorded."

The rate of increase seems to have been roughly constant since 2007.

--Mortense (talk) 13:32, 26 July 2019 (UTC)[reply]

Wouldn't methane be a 1 on this scale? Similar to Propene?

Normally stable, but can become unstable at elevated temperatures and pressures (e.g. propene)

If methane is colorless, then why does the Uranus article say, "Methane has prominent absorption bands in the visible and near-infrared (IR), making Uranus aquamarine or cyan in colour"? Is it colored only when it's a liquid, as in the clouds of Uranus? Eric Kvaalen (talk) 10:53, 4 September 2021 (UTC)[reply]

This article indicates an absorption for methane at 619 nm, which is in the visible range. Note that it has incredibly low oscillator strength, in both the gas phase and the liquid phase. That would be an orange-red absorption, which would correspond to a visual appearance of the complementary color of aquamarine or cyan. For our purposes on Earth, where we are either dealing with low density gases or small (relatively speaking) path lengths of liquids, the low oscillator strength makes these transitions, for all practical purposes, not visible. However, when dealing with the scale of clouds on a planetary atmosphere, the path length becomes much larger, probably in the tens or hundreds of kilometers. Per the Beer–Lambert law, that huge a path length change can make a huge difference in what is, practically speaking, observable. The fact is that most compounds, barring fun quantum or symmetry effects causing transitions to become forbidden, do have absorption bands in the visible range. If those transitions are genuinely forbidden, then there will be zero oscillator strength, and no observed color. Often, though, "formally forbidden" transitions do actually show up, just with fairly weak oscillator strengths. This can happen for a lot of reasons, such as pressure effects. If you have a high pressure situation, with molecules regularly hitting each other, the slight amount of molecular deformations from those collisions will slightly change the geometry, and therefore deviate from the symmetry that caused a transition to be forbidden, thus giving a weak absorption spectrum. The article I've posted here doesn't indicate much increase in oscillator strength due to the liquid phase, so I'd say the bigger effects are higher concentration due to the condensed phase and much longer path length, both of which will give a higher absorptivity due to the Beer-Lambert law. --OuroborosCobra (talk) 17:25, 4 September 2021 (UTC)[reply]

@OuroborosCobra: Thanks for the reply, which I only saw now since you didn't ping me. I can't access that article, but the title talks about the "vibrational overtone spectrum". Sounds like the absorption band at 619 nm is at around twice the frequency of one of the vibrations that cause absorption in the infrared. Or maybe thrice. I didn't know about that, but I see that Wikipedia has an article explainin' it (Overtone band). I came across an article that contains reflectivity spectra for Uranus and Neptune (Figure 1 of Hazy blue worlds: A holistic aerosol model for Uranus and Neptune, including Dark Spots), though I don't understand what the abscissa "I/F" means. You can see the absorption at 619 nm. From the text it seems that all the absorption bands one sees in Figure 1 are from methane. It talks about "k-tables" but I don't know what those are. It sounds like these absorption bands are not due to high pressure. So we can say that methane is slightly blue, but you need a long path length to see this. Eric Kvaalen (talk) 21:07, 12 February 2022 (UTC)[reply]

P.S. OuroborosCobra, I found what I/F means. "I" is intensity of radiation in a certain direction (like towards us), and "F" is the flux of incident radiation divided by π.[7] A surface that reflects equally in all directions and reflects all the radiation will have I/F equal to 1 in all directions. I and F may be functions of wavelength, in which case they're per unit wavelength or frequency. Eric Kvaalen (talk) 19:09, 14 February 2022 (UTC)[reply]

What is it 2405:201:AC01:3026:ED7B:46B:D2B4:C586 (talk) 16:30, 11 December 2022 (UTC)[reply]

I've added a short sub-section, "Wetlands" to Generation > Biological routes and added an image from the Global Methane Budget. These edits were made in collaboration with Drs Terhi Ruitta and Caroline Signori-Müller who have expertise in peatlands, as part of the WiR at the GSI. TatjanaClimate (talk) 11:14, 23 August 2023 (UTC)[reply]

carbon atom bonded to four hydrogen atoms). It is a group-14 hydride 49.145.161.229 (talk) 03:40, 26 April 2024 (UTC)[reply]