<p>The 'natural causes' of global methane emissions are, as you indicate, mostly of biological origin. To some extent it depends upon what you regard as 'natural'. There are many and differing estimates of global methane generation, of which I list a summary below. Those in bold you may regard as abiological. Values are in Mega-tonnes per year released to the atmosphere:</p>

<p>Wetlands 217</p>

<p>Fossil Fuels 96</p>

<p>Ruminants 89</p>

<p>Landfill 75</p>

<p><strong>Geological sources 54</strong></p>

<p>Freshwater 40</p>

<p>Biofuels 38</p>

<p>Rice growing 36</p>

<p><strong>Oceans - DMS  20</strong></p>

<p>Termites 11</p>

<p><strong>Wildfires 10</strong></p>

<p>It's a moot point as to whether degradation of dimethyl sulphide (DMS) is biological or not. </p>

CC BY-SA 3.0
2017-01-03T02:41:38.387Z
Do you have the source?
f.thorpe
CC BY-SA 3.0
2017-01-04T07:31:15.100Z
I can't remember the issue but I jotted the above numbers down from an article in New Scientist, a year or two ago.
Gordon Stanger
CC BY-SA 3.0
2017-01-09T19:38:51.500Z
You emphasized  "oceans" but not "freshwater"?
Spencer
CC BY-SA 3.0
2017-01-03T01:50:14.020Z
2017-01-03T01:50:14.020Z
Gordon Stanger
<p>Yes </p>

<p>It is one of most common compounds in the universe. </p>

<p><a href="https://en.wikipedia.org/wiki/Methane#Extraterrestrial_methane" rel="nofollow noreferrer">https://en.wikipedia.org/wiki/Methane#Extraterrestrial_methane</a></p>

<p>Which period of the early earth do you want to know about? the earliest atmosphere likely had less methane than now. <a href="http://science.sciencemag.org/content/308/5724/1014" rel="nofollow noreferrer">http://science.sciencemag.org/content/308/5724/1014</a>
But once life evolved methane rose.
<a href="http://www.minersoc.org/pages/Archive-MM/Volume_62A/62a-2-751.pdf" rel="nofollow noreferrer">http://www.minersoc.org/pages/Archive-MM/Volume_62A/62a-2-751.pdf</a></p>

CC BY-SA 3.0
2016-12-19T15:45:00.000Z
2016-12-19T15:45:00.000Z
John
<p>Natural gas is mostly made of methane ($\ce{CH4}$). Methane can be produced as a result of microbes eating organic matter. But can it also be naturally formed without any assistance from organic matter?  Perhaps in conditions such as those found on the early Earth?</p>

CC BY-SA 3.0
2016-02-02T00:28:32.087Z
Gasoline is not 'mostly made of methane'. You might have some more informed questions after doing [some reading](https://en.wikipedia.org/wiki/Methane#Biological_routes).
Matt Hall
CC BY-SA 3.0
2016-02-02T01:34:07.643Z
Maybe you're thinking of natural gas. Gasoline, containing things like isooctane, butane, and 3-ethyltoluene, is a much more complex hydrocarbon than methane, which is the most simple of them.
BillDOe
CC BY-SA 3.0
2016-02-04T10:19:53.617Z
<http://study.com/academy/lesson/what-is-methane-reactions-formula-quiz.html>
user5434678
CC BY-SA 3.0
2016-12-19T03:00:34.393Z
It is the most common combination of the first and fourth most common elements in universe. And one of the most common compounds in the universe. I know of dozens of ways of making methane abiotically. You really might want to refine your question.
John
CC BY-SA 3.0
2016-12-19T04:45:34.647Z
So your fundamental answer is yes, and then add a little background to it.  Perhaps discuss some that may potentially be considerable sources currently or in likely previous Earth environments, maybe 1 or 2 interesting or funny, and I'd think you'd have a great answer to satisfy this question
JeopardyTempest
CC BY-SA 3.0
2016-12-19T13:34:52.500Z
Yes. Listen to [Astronomycast Ep. 341 - The Search for Life on Mars](http://www.astronomycast.com/2016/12/ep-431-life-on-mars/)
Jan Doggen
<geochemistry><biogeochemistry><petroleum><methane>
What are the natural causes for methane formation?
Marijn 
# What are the natural causes for methane formation?

(Asked by: username_0 on 2016-02-01)

Natural gas is mostly made of methane ($\ce{CH4}$). Methane can be produced as a result of microbes eating organic matter. But can it also be naturally formed without any assistance from organic matter? Perhaps in conditions such as those found on the early Earth?

**Tags:** geochemistry, biogeochemistry, petroleum, methane

> **Comments:**
> **username_1**: Gasoline is not 'mostly made of methane'. You might have some more informed questions after doing [some reading](https://en.wikipedia.org/wiki/Methane#Biological_routes).  
> **username_2**: Maybe you're thinking of natural gas. Gasoline, containing things like isooctane, butane, and 3-ethyltoluene, is a much more complex hydrocarbon than methane, which is the most simple of them.  
> **username_3**: <http://study.com/academy/lesson/what-is-methane-reactions-formula-quiz.html>  
> **username_4**: It is the most common combination of the first and fourth most common elements in universe. And one of the most common compounds in the universe. I know of dozens of ways of making methane abiotically. You really might want to refine your question.  
> **username_5**: So your fundamental answer is yes, and then add a little background to it.  Perhaps discuss some that may potentially be considerable sources currently or in likely previous Earth environments, maybe 1 or 2 interesting or funny, and I'd think you'd have a great answer to satisfy this question  
> **username_6**: Yes. Listen to [Astronomycast Ep. 341 - The Search for Life on Mars](http://www.astronomycast.com/2016/12/ep-431-life-on-mars/)  

---

## 2 answers

### Answer by username_7 on 2017-01-03. Score: 2

The 'natural causes' of global methane emissions are, as you indicate, mostly of biological origin. To some extent it depends upon what you regard as 'natural'. There are many and differing estimates of global methane generation, of which I list a summary below. Those in bold you may regard as abiological. Values are in Mega-tonnes per year released to the atmosphere:

Wetlands 217

Fossil Fuels 96

Ruminants 89

Landfill 75

**Geological sources 54**

Freshwater 40

Biofuels 38

Rice growing 36

**Oceans - DMS 20**

Termites 11

**Wildfires 10**

It's a moot point as to whether degradation of dimethyl sulphide (DMS) is biological or not.

> **Comments:**
> **username_8**: Do you have the source?  
> **username_7**: I can't remember the issue but I jotted the above numbers down from an article in New Scientist, a year or two ago.  
> **username_9**: You emphasized  "oceans" but not "freshwater"?  

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### Answer by username_4 on 2016-12-19. Score: 1

Yes

It is one of most common compounds in the universe.

<https://en.wikipedia.org/wiki/Methane#Extraterrestrial_methane>

Which period of the early earth do you want to know about? the earliest atmosphere likely had less methane than now. <http://science.sciencemag.org/content/308/5724/1014>
But once life evolved methane rose.
<http://www.minersoc.org/pages/Archive-MM/Volume_62A/62a-2-751.pdf>


---

