<p>The terrestrial vegetation makes ca. 500 PgC (i. e. $500 \times 10^{15}$ grams of Carbon) which is rather small compared to the carbon stored in the ocean of ca. 37 000 PgC, see Fig. 6.1 in Ciais et al. 2013 <sup>1</sup>.<br>
Even if we assume that the fossil fuels reserves are the remainders of the Carboniferous period, they only add up to no more than ca. 2 000 PgC. </p>

<p>The terrestrial biosphere only makes use of a very small portion of the total available carbon.</p>

<p><sub>
<sup>1</sup> Ciais, P., C. Sabine, G. Bala, L. Bopp, V. Brovkin, J. Canadell, A. Chhabra, R. DeFries, J. Galloway, M. Heimann, C. Jones, C. Le Quéré, R.B. Myneni, S. Piao and P. Thornton, 2013. <a href="http://www.ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_Chapter06_FINAL.pdf" rel="nofollow">Carbon and Other Biogeochemical Cycles</a>. In T. F. Stocker et al. (Eds): <em>Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change</em>. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. 
</sub></p>

CC BY-SA 3.0
2015-04-17T10:24:35.723Z
@plannapus: Well spotted, I changed that to "terrestrial"
makra
CC BY-SA 3.0
2015-04-16T18:11:25.997Z
2015-04-17T10:23:49.393Z
2015-04-17T10:23:49.393Z
makra
<p>In a nutshell, if we assume that the earth's atmosphere (and water) came largely from comets, then it's simply about asking, what are comets made of - $\ce{H2O}$, $\ce{CO2}$, $\ce{CH4}$, $\ce{NH3}$, other ices, dust.    $\ce{CO2}$ is abundant, it arrived pretty much the same way the water did.    The earth has trapped/absorbed most of it's $\ce{CO2}$.   There used to be a lot more of it in the atmosphere.</p>

CC BY-SA 3.0
2015-04-15T07:19:35.487Z
2015-04-17T08:52:24.320Z
2015-04-17T08:52:24.320Z
userLTK
<p>It is believed that during the Carboniferous period, fungi and bacteria lacked the biochemical means to decompose lignin and release $\ce{CO_2}$ back to the atmosphere. So dying trees carbon became trapped in coal deposits. But whence came all carbon allowing these plants grow?</p>

CC BY-SA 3.0
2015-04-09T12:53:29.203Z
"it is known"? Is there any actual evidence?  I thought it was more speculation that a) appears logical; and b) is then used to help explain the high amount of preserved organic material (ie. coal).
winwaed
CC BY-SA 3.0
2015-04-13T12:02:26.747Z
Maybe change 'known' to 'believed' (besides, that's about as good as it gets in geology :), and offer a reference? It's a reasonable question.
Matt Hall
CC BY-SA 3.0
2015-04-13T13:14:27.867Z
thnks for help. I edited the question.
rnrneverdies
CC BY-SA 3.0
2015-04-13T19:09:18.973Z
Stellar nucleosynthesis is surely the answer to the question as it stands. It might be better to ask how the carbon cycle worked before the advent of bacterial/fungal degradation of lignin? or to think about how long (probably not too long) it took for life to evolve a way to get the carbon out.
Siv
<paleoclimatology><carbon-cycle>
Sources of $\ce{CO_2}$ during Carboniferous period
rnrneverdies
# Sources of $\ce{CO_2}$ during Carboniferous period

(Asked by: username_0 on 2015-04-09)

It is believed that during the Carboniferous period, fungi and bacteria lacked the biochemical means to decompose lignin and release $\ce{CO\_2}$ back to the atmosphere. So dying trees carbon became trapped in coal deposits. But whence came all carbon allowing these plants grow?

**Tags:** paleoclimatology, carbon-cycle

> **Comments:**
> **username_1**: "it is known"? Is there any actual evidence?  I thought it was more speculation that a) appears logical; and b) is then used to help explain the high amount of preserved organic material (ie. coal).  
> **username_2**: Maybe change 'known' to 'believed' (besides, that's about as good as it gets in geology :), and offer a reference? It's a reasonable question.  
> **username_0**: thnks for help. I edited the question.  
> **username_3**: Stellar nucleosynthesis is surely the answer to the question as it stands. It might be better to ask how the carbon cycle worked before the advent of bacterial/fungal degradation of lignin? or to think about how long (probably not too long) it took for life to evolve a way to get the carbon out.  

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## 2 answers

### Answer by username_4 on 2015-04-16. Score: 3 | Accepted answer

The terrestrial vegetation makes ca. 500 PgC (i. e. $500 \times 10^{15}$ grams of Carbon) which is rather small compared to the carbon stored in the ocean of ca. 37 000 PgC, see Fig. 6.1 in Ciais et al. 2013 1.  
Even if we assume that the fossil fuels reserves are the remainders of the Carboniferous period, they only add up to no more than ca. 2 000 PgC.

The terrestrial biosphere only makes use of a very small portion of the total available carbon.

1 Ciais, P., C. Sabine, G. Bala, L. Bopp, V. Brovkin, J. Canadell, A. Chhabra, R. DeFries, J. Galloway, M. Heimann, C. Jones, C. Le Quéré, R.B. Myneni, S. Piao and P. Thornton, 2013. [Carbon and Other Biogeochemical Cycles](http://www.ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_Chapter06_FINAL.pdf). In T. F. Stocker et al. (Eds): *Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change*. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

> **Comments:**
> **username_4**: @plannapus: Well spotted, I changed that to "terrestrial"  

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### Answer by username_5 on 2015-04-15. Score: 1

In a nutshell, if we assume that the earth's atmosphere (and water) came largely from comets, then it's simply about asking, what are comets made of - $\ce{H2O}$, $\ce{CO2}$, $\ce{CH4}$, $\ce{NH3}$, other ices, dust. $\ce{CO2}$ is abundant, it arrived pretty much the same way the water did. The earth has trapped/absorbed most of it's $\ce{CO2}$. There used to be a lot more of it in the atmosphere.


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