[Terrapreta] Fwd: Fwd: Global Carbon Cycle

[Sean K. Barry]

Hi Kevin, et. al.

Kevin wrote:
This is a very simplistic attempt to explain some of the factors 
influencing CO2 in the atmosphere.

Kevin, that view is too simplistic.  You should not equate the biosphere and the atmosphere.  Harvesting trees may not remove any carbon from the biosphere; it just kind of moves it around within in it.  But, harvesting trees definitely will put more carbon into the atmosphere, than was there before.  Even if new trees are allowed to grow in after, the original trees have been removed, the carbon from the original trees (especially if it is a large mature stand of trees), will not be taken up by the new growth for perhaps hundreds of years.

Too much green house gases in the atmosphere is the problem behind global warming (not carbon in the biosphere).  The cause for the increase in atmospheric GHG is now being primarily viewed as due to the introduction of the GHG into the atmosphere by human activity.

8: Cow belches and termite farts don't matter either, in that they 
simply took carbon from the biosphere, and then gave it back later.

This is another example of too simplistic of an assertion.  Sugar, corn, wheat, sawdust; all pig, and/or termite food are not GHG gases.  They are not in the atmosphere causing global warming.  It is true, too, that most of them probably contain carbon and all are in the biosphere.  But, when a cow or a termite "farts", the animal/insect releases methane (CH4) into the atmosphere, which is a highly potent GHG.  You are right, that there was no net change in the amount of carbon in the biosphere.  But that it not the point, is it?
The methane released into the atmosphere is causing the global warming, not the carbon in the pig or termite food.

3: Slower "recycling" of carbon that is temporarily sequestered in 
trees, or in construction materials, will tend to lower CO2 in the 
atmosphere, until such time as it is all returned within the Biosphere 
as a lifeform.

At such a time that carbon from construction materials is all returned within the Biosphere, will this always increase the amount of CO2 in the atmosphere?  I do know the answer to this question.   Do you?

Regards,

SKB


  ----- Original Message ----- 
  From: Kevin Chisholm<mailto:kchisholm at ca.inter.net> 
  To: lou gold<mailto:lou.gold at gmail.com> 
  Cc: Terrapreta at bioenergylists.org<mailto:Terrapreta at bioenergylists.org> 
  Sent: Wednesday, June 06, 2007 12:56 AM
  Subject: Re: [Terrapreta] Fwd: Fwd: Global Carbon Cycle


  Dear Lou

  This is a very simplistic attempt to explain some of the factors 
  influencing CO2 in the atmosphere.

  Consider a "box" that represents the Biosphere. All Carbon in the 
  Biosphere is involved with a "life process"... trees, algae, grass, 
  animals, plants, etc. The carbon content in this biosphere box is in 
  equilibrium, neither increasing nor decreasing.

  Consider what happens when 1 unit of "fossil carbon" is added to the 
  biosphere box as CO2. There will be an initial increase in the 
  atmosphere. If there was space to grow, adequate sun, water and 
  nutrients, and if the upper limiting value for CO2 was not exceeded, 
  then it would be incorporated into plants, and other bio-forms. The 
  atmosphere would then come to an equilibrium.

  If you wreck a portion of the biosphere (cutting trees, killing animals, 
  clearing land, etc, the system will return to the same equilibrium state 
  that existed before the disruption. Total carbon in the biosphere would 
  be the same, because none more was added, and none was removed. The only 
  way to lower the carbon in the biosphere to get it back to its original 
  level is to remove carbon from the biosphere. This can be done by 
  converting some of the biomass in the biosphere into a weight of carbon 
  equal to the weight of fossil carbon originally added.

  So, to fit your query into the above framework...

  1: It doesn't matter if trees are harvested, and allowed to decompose, 
  in that no carbon is removed from the biosphere. There would be a short 
  term increase as the tree rotted, but no long term net gain or net loss.

  2: It doesn't matter if a portion of the trees are burned... the release 
  is faster, but there is no net change in Carbon content.

  3: Similarly, if the wood is used in construction, it is temporarily 
  removed from the biosphere, but over the long term, it will be returned.

  4: Similarly, with soil that is denuded of its organics... a short term 
  spike of CO2 release, but no long term change.

  5: If the land is built upon, it reduces the effective working space of 
  the Biosphere, and the CO2 in the atmosphere will tend to rise, unless 
  the plants can take up more CO2. However, there was no net change in 
  biosphere carbon content.

  6: If the land was allowed to return to forest, then the system would 
  return to its original state.

  7: If the land is converted to pasture, atmosphere carbon content would 
  increase because there would be only a fraction of one year's growth 
  sequestered as biomass.

  8: Cow belches and termite farts don't matter either, in that they 
  simply took carbon from the biosphere, and then gave it back later.

  Thus, we see:
  1: Carbon in the biosphere increases only when new carbon is added to 
  the biosphere. (Fossil fuels, semi-fossil carbon such as peat bogs and 
  methane hydrate, etc)

  2: Carbon in the biosphere is only decreased when carbon is removed from 
  the biosphere. (Charcoal buried as terra preta, compressed CO2 stored in 
    wells or caverns, etc)

  3: Slower "recycling" of carbon that is temporarily sequestered in 
  trees, or in construction materials, will tend to lower CO2 in the 
  atmosphere, until such time as it is all returned within the Biosphere 
  as a lifeform.

  The bottom line is that if some people buy carbon credits and burn 
  fossil fuels, there will be an increase in the carbon level of the 
  Biosphere unless an equivalent amount of carbon was removed from the 
  biosphere. Real carbon removal, not just "paper credits." The only way 
  to maintain current levels of carbon in the biosphere is to remove a 
  weight of carbon equivalent to that which was added as fossil fuel. The 
  best that the present Carbon Trading system can do is maintain the 
  present excessive levels of C in the biosphere. However, with Global 
  Warming being evidenced as it is now, the present Carbon Trading system 
  is institutionalizing a state of "much too little, far too late."

  I hope that the above has some "elements of clarification".

  Best wishes,

  Kevin

  lou gold wrote:
  > Hello Again,
  > 
  > I have to admit that I haven't understood all aspects of these system so
  > please let me off the hook of defending them all. I want to focus on just
  > one:
  > 
  >>
  >>
  >> Consider a "mature" forest. By definition, a "mature" forest has 0
  >> Annual Increment... there is no net gain or loss of biomass... the
  >> forest mass lost by dying trees is made up for by new growth from
  >> younger trees. If the trees are cut and used for building, then the
  >> carbon content of the wood is sequestered in a building, and new space
  >> is freed up for growth of new trees to take Carbon out of the
  >> atmosphere. A mature forest does nothing to alleviate the Greenhouse
  >> Effect, and as far as I can see, saving Mature Forests is a blatant
  >> Carbon Credit Scam.
  > 
  > 
  > It works this way. 20% of Brazil's carbon emissions is smoke from
  > deforestation. Then there is the added emissions of whatever is released
  > from the denuded soil. Then there is whatever is  burned for fuel. Then
  > there is the life-cycle releases as products become wastes. The point is
  > that the natural carbon sink retains its carbon much longer and in decay
  > slowly contributes to ecosystem functions such as creating habitat,
  > filtering water and building new soil. Indeed the quickly growing young
  > plantation draws down CO2 much faster, but it is nowhere near the pace of
  > the release in deforestation.
  > 
  > There are two processes we want to reward. 1) Slow the release into the
  > atmosphere of carbon from wherever it is "sunk" and 2) retrieve from the
  > atmosphere into new sinks in many forms (like terra preta). The thought is
  > that it will take public policies to incentivize these processes.
  > 


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