[Terrapreta] Catalyst: Carbon Bigfoot

[Sean K. Barry]

Hi Duane,

  ----- Original Message ----- 
  From: Duane Pendergast<mailto:still.thinking at computare.org> 
  To: 'Sean K. Barry'<mailto:sean.barry at juno.com> ; 'Kevin Chisholm'<mailto:kchisholm at ca.inter.net> 
  Cc: 'Terrapreta'<mailto:terrapreta at bioenergylists.org> 
  Sent: Sunday, December 09, 2007 9:40 AM
  Subject: RE: [Terrapreta] Catalyst: Carbon Bigfoot


  Sean, Kevin



  Is the use of char and other biomaterial for fuel really carbon neutral if looked at on a macro scale? Probably not!  There seems a tendency to replace forests, with large carbon content - with other crops for fuel with little standing carbon content. Thus the use of char for fuel may turn out to be carbon positive with respect to the atmosphere rather than carbon neutral as simply assumed by most climate change aficionados. Environmental activists are just starting to catch on to that possibility. 



  I'm leery of the move to bio-fuels for that reason and the fact that we humans and other biota need something to eat. Our government (Canada) is putting policy in place to encourage the use of bio-fuels. That policy seems driven by a perceived need to respond to voter's reaction to polls on climate change while soliciting support from farm and bio-fuel interest groups. On the positive side the policy might be a stepping stone to better thought out solutions for greenhouse gas management.   



  Duane

You assume here that charcoal is made only from wood taking down an entire forest and replacing it with an energy crop.  Were that the only way charcoal was made, I would agree.  But, then, don't do things this way and the outcome will be different.  Charcoal can be made from any biomass, even agricultural crop residuals.

No humans eat Miscanthus gigantius or switch grass, do they?

Burning biomass directly or burning the fuels extracted from biomass always results in the same exhaust products - CO2 and H2O.  They are both GHG, but because the carbon came relatively recently from the atmosphere before it was emitted back into it, then it is viewed as "carbon neutral", because is merely recycles atmospheric carbon.  When atmospheric carbon is taken out of the atmosphere and put into a sink of significant permanence (greater than several 100 years?), then it is viewed as a "carbon negative" process.

Fossil carbon has not been in the atmosphere for 300+ million years.  When fossil carbon is reintroduced to the atmosphere, that is a "carbon positive" process. It increases the average carbon concentration (CO2) in the atmosphere.  The average CO2 concentration has risen from 250 ppm (parts per million) to over 380 ppm in just 150 years of intense fossil fuel burning since the dawn of the industrial revolution.

Below is an equation used to compute the change in average global temperature (in degrees Fahrenheit) that's comes with increasing average CO2 concentration in the atmosphere.

  


The 5.35 times natural log of (380/250) is 2.24.   This estimates then that the average global temperature has risen 2.24 degrees F as a result of increased CO2 concentrations that have occurred since the beginning of the industrial revolution (250 ppm => 380 ppm).  There are similar equations for other GHG, like Methane-CH4 and Nitrous oxide-N2O.

Regards,

SKB
-------------- next part --------------
An HTML attachment was scrubbed...
URL: /pipermail/terrapreta_bioenergylists.org/attachments/20071209/9ea60580/attachment.html 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: image/png
Size: 858 bytes
Desc: not available
Url : /pipermail/terrapreta_bioenergylists.org/attachments/20071209/9ea60580/attachment.png