[Terrapreta] One Tonne of charcoal = X?? amount of sequestered GHGs

[joe ferguson]

See inline question below (in *bold.* )

Sean K. Barry wrote:
> Hi Michael,
>  
> You ask, "Can any one who is clever at sums, tell me how much GHG is 
> sequestered per tonne of Charcoal?"
>  
> You have got to know, that I am going to try and answer that. 
>  
> I've think I've read from the work of Dr. Michael Antal, Jr., from the 
> University of Hawaii, that charcoal can be up to 93-95% pure carbon in 
> the charcoal and maybe only as much as 80some%, the rest being carbon 
> containing volatile matter (but, which can apparently be decomposed by 
> soil microorganisms over time) and/or ash.
>  
> So, conservatively a metric ton of charcoal (dominated by 80% pure 
> carbon), probably then amounts to ~800 kg of carbon.  The most 
> prevalent carbon containing gas, which enters the atmosphere from 
> anthropogenic sources, is, I think, carbon dioxide (CO2).  The sum 
> 12+16+16 = the atomic weight of one carbon plus two oxygen atoms (or 
> the weight of a mole number of CO2 molecules, measured in grams).  
> This is 44 grams per mole, 12 parts carbon, and 32 parts oxygen.  So, 
> 800 kg of pure carbon is equivalent to ~2933 (= 800*44/12) kilograms 
> of CO2 gas in the atmosphere.
>  
> The IPCC, the Kyoto Protocol, and others always talk about "carbon 
> equivalent" amounts, though.  The oft quoted 6Gt per year from 
> anthropogenic sources means 6 billion tons of just the weight of 
> carbon atoms put into the atmosphere.  Those atoms are parts of a 
> larger weight (like *44/12) of molecular gaseous molecules that 
> contain carbon (CO2, CH4, etc).
>  
> Additionally, some very potent GHG do not even contain one single atom 
> of carbon (e.g. nitrous oxide (N2O), for instance).  It still is 
> measured in what are called "carbon equivalents".  The number of 
> molecules in a volume of nitrous oxide (N2O) gas has an effect on the 
> atmosphere, which is equivalent to that from a volume of gas 
> containing 296 times the same number of carbon containing molecules.
*Can anyone refer me to the durations these other GHGs stay in the 
atmosphere?  that is, their half-lives.  We know that the CO2 stays 
until it is removed by some specific mechanisms.  But some of the NOx 
SOx, etc, GHGs are removed by photo-activated reaction, washing out in 
the acid rain, etc.*
>  
> I hope this helps.
>  
> SKB
> ------------------------------------------------------------------------
>
> _______________________________________________
> Terrapreta mailing list
> Terrapreta at bioenergylists.org
> http://tech.groups.yahoo.com/group/biochar/
>   

-------------- next part --------------
An HTML attachment was scrubbed...
URL: /pipermail/terrapreta_bioenergylists.org/attachments/20070602/2c395500/attachment.html