[Terrapreta] Catalyst: Carbon Bigfoot

[Chuck Yokota]

Hi Sean,

 

We agree on the math about the amounts of charcoal to sequestrate
carbon, except that I (silly American) slipped into using acres when I
meant hectares.  My focus was that the farmer would see good
productivity gains from the first 5 or 10 tons per hectare, but not
enough additional productivity gains from putting on more charcoal to
justify the cost.  Additional sequestration would depend on some form of
carbon credits.

 

One small quibble:  The total surface of the earth, land and ocean, is
510 million square kilometers.  The land area is 149 million square
kilometers (14.9 billion hectares).

 

Chuck

 

________________________________

From: Sean K. Barry [mailto:sean.barry at juno.com] 
Sent: Monday, December 10, 2007 2:55 PM
To: Terrapreta; Chuck Yokota
Subject: Re: [Terrapreta] Catalyst: Carbon Bigfoot

 

Hi Chuck,

 

Check you math?

 

Global average CO2 concentrations have risen to 380 ppm now, in 2007,
versus 250 ppm in 1850.  The ecology of the Earth, by itself, cycles 120
billion tons of carbon (~440 giga-tons of CO2) into and out of the
atmosphere every year.  Humans add 6 billion tons of carbon to the
atmosphere every year, primarily from burning fossil fuels.

 

It is not the goal of GHG reductions to bring the ~3 trillion (3000
billion) tons of CO2 down to zero tons of CO2 immediately.  Rather, to
reduce CO2 concentrations to pre-industrial levels would only require
going from ~3 trillion tons of CO2 down to (250/380) * 3 = ~2 trillion
tons of CO2.  Hence, only removing ~1 trillion tons of CO2, which is
equivalent to (12/(12+16+16))*1E9 = 272 billion tons of carbon.

 

Since charcoal is 90-95% pure carbon, then 272 billion tons of carbon is
approximately 300 billion tons of charcoal.  Since you claim that there
are 5 billion hectares of arable land, then it seems to me that the
desired reduction in atmospheric carbon could be achieved by putting 10
tons/hectare of 5 billion hectares of land, for 6 consecutive years.
Additionally, the same could be accomplished by putting 50 tons of
charcoal per hectare onto only 300 million hectares of land for 20
years.

 

The entire land surface of the Earth is ~510 million square km (or ~51
billion hectares).  If some of the land other than the 10% arable land
were used as a place to sequester charcoal carbon into soil, then we
might be able to do the necessary sequestration sooner and EXPAND the
amount of arable land at the same time (i.e. making Terra Preta soil
from degraded soil, reclaiming it, and making deserts bloom, if you
will).

 

If you (or anyone else on this list) find any error in my calculations
here, then please let me know and we can discuss it.  Please bear in
mind that I am accepting your numbers, Chuck, of 3000 billion tons of
CO2 in the atmosphere now and 5 billion hectares of arable land.

 

Regards,

 

Sean K. Barry
Principal Engineer/Owner
Troposphere Energy, LLC
11170 142nd St. N.
Stillwater, MN 55082-4797
(651)-285-0904 (Work/Cell)
(651)-351-0711 (Home/Fax)

sean.barry at juno.com

	----- Original Message ----- 

	From: Chuck Yokota <mailto:cyokota at innovativeenergyinc.com>  

	To: Terrapreta <mailto:terrapreta at bioenergylists.org>  

	Sent: Monday, December 10, 2007 1:28 PM

	Subject: Re: [Terrapreta] Catalyst: Carbon Bigfoot

	 

	
	The Earth's atmosphere holds roughly 800 billion tons of carbon
in 3000
	billion tons of carbon dioxide.  Field experiments mentioned on
the list
	use 5 to 10 tons of char per hectare.  There are 5 billion
hectares of
	agricultural land in the world.  If every farmer applied 10 tons
of char
	per hectare, that would take 50 billion tons out of the carbon
cycle.
	This would still leave carbon dioxide levels far above
pre-industrial
	levels.  Farmers would need to apply more than 50 tons per acre
to bring
	carbon dioxide levels back to pre-industrial levels.  I would
expect
	that the agricultural value of more char would hit an economic
limit of
	diminishing returns long before it reached that point.  We are
not in
	danger of depleting the Earth's atmosphere of carbon dioxide.
	
	Kevin wrote:
	
	Dear Lou
	
	lou gold wrote:
	> Hi Duane,
	>
	> del...
	> The only thing that I question is your assertion that we must
continue
	
	> to generate CO2 in order to feed the plants. It seems to me
that there
	
	> is a huge reservoir already available. Do you know of any
studies or 
	> models that might suggest when CO2 will "peak" and require
replacement
	
	> inputs, perhaps from fossil fuels?
	The Greenhouse Industry has done alot of work, and research
papers, on 
	the benefits and economics of CO2 to greenhouse atmospheres in
teh 
	winter, when greenhouse ventilation is low. The plant canopy
strips the 
	CO2 from teh closed atmosphere very quickly. Commonly propane or
natural
	
	gas is burned, with products of combustion vented into teh
growing 
	space, to enrich CO2 to enhance plant growth.
	
	A Google search for "greenhouse CO2 Enrichment" gives 21 hits;
with no 
	quotes, you get about 340,000 hits.
	
	Best wishes,
	
	Kevin
	
	
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