Talk:Methane/Archive 1

Alessandro Volta and methane

The wikiarticle about Alessandro Volta credits him with the discovery of methane; the wiki reports that he discovered methane during his studies of chemistry (1775-1776). If it's true, maybe it could be worth mentioning Volta also on the article about methane. — Preceding unsigned comment added by 151.20.46.182 (talk • contribs) 18:06, 21 January 2009 (UTC)

Volta has since been added to this article. -- Beland (talk) 02:42, 21 June 2024 (UTC)

Offsetting methane calthrates and atmospheric presence

Direct absorption of carbon dioxide CO2 and methane CH4 gases from the environment and their conversion into nano solution and nano solnd pressure

(release date 06.01.2010) - REF 40

In this paper, results of processes will be introduced for tH4 gases direct from environment and their conversion into nano materials of here, concurrently within the processes of extraction of these gases in a simple reactor, we have managed to produce energy and oxygen.

http://www.keshefoundation.org/pdfs/CO2_paper.pdf

```` — Preceding unsigned comment added by 71.110.202.44 (talk) 01:57, 29 July 2012 (UTC)

Wikipedia generally needs secondary sources, not so much research papers. -- Beland (talk) 02:43, 21 June 2024 (UTC)

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)

This has since been added to the article. -- Beland (talk) 02:43, 21 June 2024 (UTC)

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)

Methane and Nitrogen are potentially deadly to humans as an asphyxiant. Methane is readily available from community Natural Gas distribution pipelines, though it is now 'flavored' with H2S (Hydrogen Sulfide) to give early warning to potential gas leaks - natural gas is predominantly CH4 (Methane) by percentage. On a side note, the H2S used in the civilian distribution of Natural Gas is extremely low concentration, below 10-PPM...as H2S is extremely offensive to the olfactory senses...it is lethal above 20,000-PPM. REFERENCE MSDS SHEETS for 50-LD on H2S, while Methane MSDS can be read at: (http://www.vngas.com/pdf/g56.pdf)

Methane poisoning can include the effects of: blurred vision, CNS Depression and Rapid Heart Rate, predominantly as a function of asphyxia - though there is no risk of carcinogenic effects. http://www.wrongdiagnosis.com/c/chemical_poisoning_methane/symptoms.htm

Methane is also heavier than air, not lighter than air. (http://www.vngas.com/pdf/g56.pdf - page 3) —Preceding unsigned comment added by 72.147.141.172 (talk) 01:43, 11 July 2010 (UTC)

No, methane is lighter than air. (See various talk entries below.) The linked MSDS has moved, try this one: (http://avogadro.chem.iastate.edu/MSDS/methane.pdf) Toward the end you'll find Section 9: Physical and Chemical Properties. Note the SPECIFIC GRAVITY (Air = 1): 0.554. This means it is about half as heavy as air, and will not pool to form concentrations as heavier-than-air vapors might. DonWW (talk) 16:17, 27 June 2012 (UTC)

The phrasing in the article has since been changed so as not to awkwardly refer to workplaces only. -- Beland (talk) 02:46, 21 June 2024 (UTC)

METHANE DISCHARGES STARTED IN ARCTIC OCEAN

The end of the world was announced but few noticed it. In a story about the dissappearing Ice in the North, was a note about the Alarming start of large scale Methane discharges.

Discharges that parrell those on the Permian/Triassic boundary.

It gives one pause. It may explain the puzzling silence of the heavens in a Universe which seems to always favor the start of life.

The natural evolution of life would never be 100 percent energy efficient on any world.

As life grows and becomes more complex it leaves an increasing mound of leftovers in the ground, inevitably, everytime.

When a form appears that is capable of inter planet communication it simultaneously achieves the ability to harvest and thrive on the leftovers which life has naturally gone through to produce its sentient form.

It is a "freebie" but with a terrible hidden cost that is realized to late. Life celebrates its sudden abundance of energy like a teenager on a motorcycle, and by the time it realizes the score, its too late.

If this be true, and I think it is, the one good thing we should do now is set up a beacon to transmit a warning to the Universe, in hopes that it will last long enough to be caught early enough in the brief 100 years of another world, and that that world will catch it in time, and survive, and progress.

Dan Pride DanPride (talk) 19:51, 28 August 2008 (UTC)

How is methane going to destroy the world? It lasts in the atmosphere for 8 years! hardly a period of time that people will not survive.

No what is the biggest danger in the world is idiots like you who think the end is here unless we all go back to a non industrilised society without oil etc —Preceding unsigned comment added by 121.73.44.28 (talk) 03:32, 28 February 2009 (UTC)

atmospheric methane is overwhelmingly due to oceans releasing it naturally, has nothing to do with with industrialized society 67.70.118.33 (talk) 06:23, 25 December 2022 (UTC)

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) Manure pits can crust over, trapping methane production underneath the crust. When the pit is agitated prior to application to the land, all the entrapped methane is released at once. Yes, H2S can also be a risk, but if the media say it was methane , I suppose it was.50.65.22.103 (talk) 12:14, 9 December 2019 (UTC)

H2S is the risk when working with manure pits not Methane

Source: I’m a farmer Bogman bass (talk) 18:30, 29 January 2020 (UTC)

Manure pits are not mentioned in this Wikipedia article. -- Beland (talk) 02:47, 21 June 2024 (UTC)

Goodland and Anhang analysis

The attribution of livestock's share of GHG simultaneously uses the 20-year GWP and the 100-year GWP for methane, with the former applied only to methane from livestock [page 14 of https://www.worldwatch.org/files/pdf/Livestock%20and%20Climate%20Change.pdf ] The attribution is thus meaningless and has been removed. OnceJolly (talk) 04:21, 15 July 2016 (UTC)

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. — Preceding unsigned comment added by 24.51.239.30 (talk • contribs) 00:14, 19 March 2007 (UTC)

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)

The correct reaction of the combustion of CH4 should be CH4(g) + 2O2(g) -> CO2(g) + 2H2O(l) —Preceding unsigned comment added by Reddyb2 (talk • contribs) 17:45, 2 October 2008 (UTC)

Yup, it was fixed loooong ago (you're responding to a question from 2003:). Article presently says "CH<sub>4</sub>(g) + 2O<sub>2</sub>(g) → CO<sub>2</sub>(g) + 2H<sub>2</sub>O(l) + 890 kJ/mole". DMacks (talk) 17:51, 2 October 2008 (UTC)

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]

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[2] 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

Global warming potential 2

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

This appears to have since been fixed. -- Beland (talk) 03:09, 21 June 2024 (UTC)

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)

Discussion of methane on other solar system bodies, including Titan, has since been added. -- Beland (talk) 03:12, 21 June 2024 (UTC)

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))

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)

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!

The density cited (0.717) sems to be the densit at 273K. The density at 298K is 0.656. (Westy32 (talk) 12:08, 1 April 2010 (UTC))

As a quick fix, I just added temperature to the infobox. Materialscientist (talk) 09:34, 2 April 2010 (UTC)

On 26 Sep 2020 @Mina.farhang: changed density to 0.717 kg/cubic meter at 0C, from 0.717 g/liter. Figure is 0.554 kg/cubic meter in https://www.aqua-calc.com/calculate/volume-to-weight/substance/methane-coma-and-blank-gas I will change to match that source unless someone has better source? Numbersinstitute (talk) 22:08, 29 September 2020 (UTC)

Aqua-calc seems to be a minority view. I found the following sources, and the most reliable seems to be UNFCCC, so I will cite that in the article. I leave the others here, since they do vary, to show the consensus in the field. The last item, NIST is interesting in saying how they calculated their number. It's useless to cite since they don't give temperature or pressure, but the value implies an average temperature of -7C. The table shows units reported by each source, and converted to kg/cubic meter, and converted to 0C (by ratio of degrees K) to show the consistency. Table also shows kg per standard cubic foot (60F, 1atm) as used for US natural gas industry. Numbersinstitute (talk) 20:11, 2 October 2020 (UTC)

Sources for Methane Density

Source	Date	temp K	temp C	temp F	pressure	lb/cu.ft	kg/cu.meter	g/scf	g/L=kg/cu.meter	kg/cu.meter at temp reported	kg/cu.meter at 0C	Link	kg/scf
Aqua calculator	10/1/2020	273	0.0		1 atm	0.0346	0.554			0.554	0.554	https://www.aqua-calc.com/calculate/volume-to-weight/substance/methane-coma-and-blank-gas	0.0148
IPCC, 1996, vol. 3, p. 1.124	6/30/2004	273	0.0				0.7154			0.715	0.715	https://cdm.unfccc.int/methodologies/inputsconsmeth/MGM_methane.pdf	0.0192
MGM via UN FCCC	6/30/2004	273	0.0				0.7157			0.716	0.716	https://cdm.unfccc.int/methodologies/inputsconsmeth/MGM_methane.pdf	0.0192
Matheson Tri-Gas	3/10/2009	273	0.0						0.7170	0.717	0.717	https://www.mathesongas.com/pdfs/msds/MAT14160.pdf	0.0192
Advanced Gas Technologies via U Florida	2/8/2010	273	0.0						0.7170	0.717	0.717	https://rsc.aux.eng.ufl.edu/_files/msds/343.pdf	0.0192
Matheson via Harper College	9/9/2010	273	0.0						0.7170	0.717	0.717	http://dept.harpercollege.edu/chemistry/msds1/Methane%20gas%20Matheson.pdf	0.0192
Gas Innovations (ignore typo@25C)	12/15/2011	273	0.0						0.7170	0.717	0.717	http://gasinnovations.com/literature/MSDS-Sheets/MSDS-METHANE.pdf	0.0192
Matheson	7/10/2020	273	0.0						0.7170	0.717	0.717	https://www.chemadvisor.com/matheson/database/msds/mat14160000800003.pdf	0.0192
MGM via UN FCCC	6/30/2004	288	15.0	59	1.013 bar		0.678			0.678	0.715	https://cdm.unfccc.int/methodologies/inputsconsmeth/MGM_methane.pdf	0.0192
Southern gas Services via U Missouri	7/17/2012	288	15.0		101.3 kPa		0.680			0.680	0.717	http://www.nwmissouri.edu/naturalsciences/sds/m/Methane%20compressed%20gas.pdf	0.0192
EDF	1/30/2012	289		60	1 atm			19.23		0.679	0.718	https://www.pnas.org/highwire/filestream/608631/field_highwire_adjunct_files/0/SD01.xlsx	0.0192
Praxair "Compressed Methane"	10/17/2016	289	15.6		1 atm		0.660			0.660	0.698	https://www.lindeus.com/-/media/corporate/praxairus/documents/sds/methane-ch4-safety-data-sheet-sds-p4618.pdf?la=en&rev=af36e08ee7e3466faac05b3e571e0de8	0.0187
IPCC, 1996, vol. 3, p. 1.124	6/30/2004	293	20.0				0.6666			0.667	0.715	https://cdm.unfccc.int/methodologies/inputsconsmeth/MGM_methane.pdf	0.0192
MGM via UN FCCC	6/30/2004	293	20.0				0.667			0.667	0.716	https://cdm.unfccc.int/methodologies/inputsconsmeth/MGM_methane.pdf	0.0192
Air Products via Iowa State	1/5/2000	294	21.1	70	1 atm	0.042				0.673	0.725	https://web.archive.org/web/20160305021141/http://avogadro.chem.iastate.edu/MSDS/methane.pdf	0.0194
MGM via UN FCCC	6/30/2004	298	25.0				0.656			0.656	0.716	https://cdm.unfccc.int/methodologies/inputsconsmeth/MGM_methane.pdf	0.0192
Airgas	3/13/2019	298	25.0	77		0.0423				0.677	0.739	https://www.airgas.com/msds/001033.pdf	0.0198
NIST US average of 6,811 natural gas samples	7/14/2015					0.0458				0.734		https://www.nist.gov/document/ncwm-2014-annual-report-sp-1193-st-appendix-e-0	0.0000

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))

No because methane is a fossil fuel. Qemist (talk) 22:28, 30 October 2009 (UTC)

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)

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)

Living plant sources

According to [3] 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 [4] 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" [5]--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)

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)

Belated thanks! -- Beland (talk) 01:23, 18 June 2024 (UTC)

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)

Moved here from science ref desk

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 <sup>T C</sup> 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 <sup>T C</sup> 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 CO<sub>2</sub> 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.

If air is displaced purely by CO2 then it can act as an asphyxiant at relatively moderate (5-8% I think) concentrations because it messes up the equillibrium with hemoglobin. If it is displaced by a different gas then you can breathe O2 at much lower percentages. The 19.5% quotation is of I think OSHA health regulations. —Preceding unsigned comment added by 12.232.225.131 (talk) 04:22, 15 July 2010 (UTC)

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)

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

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)

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)

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)

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

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)

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

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)

Unhealthy?

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

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

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)

This has apparently since been removed from the article. -- Beland (talk) 06:28, 21 June 2024 (UTC)

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 [6].

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)

Hey, Wikipedia is written by volunteers; there's no need for swearing. These stats have apparently since been replaced. -- Beland (talk) 06:31, 21 June 2024 (UTC)

Cow farts

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

That's now covered in Methane#Ruminants and Flatulence#Environmental impact. -- Beland (talk) 06:33, 21 June 2024 (UTC)

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)

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)

220 tmes as much CO2 in the atmosphere

The intro section says:

"The total warming effect of CH
<sub>4</sub> is smaller than that of CO
<sub>2</sub>, since there is approximately 220 times as much CO
<sub>2</sub> in the Earth's atmosphere as methane."

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<sup>-2</sup>
• CH4 in the atmosphere has risen from 0.7 to 1.745 ppm. Radiative forcing: 0.48 Wm<sup>-2</sup>

(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)

References

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)

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)

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)

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.[7][8] --Itub (talk) 09:53, 10 December 2007 (UTC)

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)

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)

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)

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)

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)

Since fixed. -- Beland (talk) 07:04, 21 June 2024 (UTC)

Extrasolar methane

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

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

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.[9] --Itub (talk) 12:55, 1 April 2008 (UTC)

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)

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)

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

Sources and Sinks

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)

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

Radicals

• I think there is a problem with uaing their symbol, isn't it? This way $^{\cdot }$ we get a small dot and this way $^{\bullet }$ 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)

This markup has since been converted to use {{chem2}}. -- Beland (talk) 07:04, 21 June 2024 (UTC)

Historical Data

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)

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

Failure of understanding

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)

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)

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)

Bond angle is NOT 109.5 degrees

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)

This seems like the correct way to write such a number given the implied accuracy of significant figures, which applies to all of the physical constants reported. -- Beland (talk) 07:04, 21 June 2024 (UTC)

Electronegativity

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)

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)

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)

5 Dec Chembox revert

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)

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)

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)

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)

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)

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)

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)

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)

Methane in Earth's atmosphere request

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

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

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

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

Melting Point

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)

-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)

Edit war over dinosaurs

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)

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.[10] 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)

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)

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)

Atmospheric Methane

"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)

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)

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)

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)

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)

Why an appendix?

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)

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

Its about to store that Methane Gas

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)

Ozone Depletion and Methane clarity

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)

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)

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

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)

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)

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)

High boiling point

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)

• 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)

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)

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

N<sub>2</sub>, O<sub>2</sub> and CH<sub>4</sub> 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 CH<sub>4</sub> remains at liquid at temperatures where N<sub>2</sub> and O<sub>2</sub> are gases is that methane is more polarisable than dinitrogen or dioxygen.

Ben (talk) 22:26, 22 October 2009 (UTC)

• 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)

Net lifetime

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)

The different estimates are now covered in Atmospheric methane#Mean lifespan. -- Beland (talk) 07:17, 21 June 2024 (UTC)

Methane rocket fuel can be manufactured on Mars

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)

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)

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)

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)

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)

This seems to have since been clarified in the article. -- Beland (talk) 07:20, 21 June 2024 (UTC)

Assessment comment

The comment(s) below were originally left at Talk:Methane/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.

Comment(s)

Press [show] to view →

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)

Last edited at 11:45, 8 May 2007 (UTC). Substituted at 23:46, 29 April 2016 (UTC)

Generation, Occurrence, and AOM sections

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)

New references for the sections: Generation, Occurrence, and AOM

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)

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)

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)

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)

Color

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)

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)

@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)

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.[11] 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)

Chemistry

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

New wetlands sub-section

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)

Methane

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