[permaculture] Global Carbon Budget and the "trees as lungs" metaphor

robscott at freeshell.org robscott at freeshell.org
Fri Oct 21 02:42:18 EDT 2005

These numbers are multiplied by 10^15 grams for the total Carbon on Earth. 
That is, you multiply the numbers below times 1,000,000,000,000,000 to get 
the number of grams of carbon on earth in each sink and annual flux rates.

major carbon "sinks"
oceans				38,000
soils				1,500
atmosphere			750
terrestrial plants		560

carbon "fluxes" (per year)
sequestration by plants		+120
respired by plants		-60
respired by soils		-60

into oceans			+92
out of oceans			-90

increase in atmosphere		+3.2
fossil fuel emissions		-6
destruction of vegetation	-0.9

Fossil fuel emissions, destruction of vegetation add 6.9 every year.
The ocean and the atmosphere take back 5.2.
The remaining 1.7 is unaccounted for, in what has been termed "the missing 
Carbon sink".

Genest, I don't have a global O budget in front of me but I'm pretty sure 
most of the Oxygen on the planet is in water (H20) and soil (SiO). Do with 
that what you will. You can say the trees "exhale" O2 and so do the oceans 
and the soils. They also sequester it. The crucial distinction is whether 
the two balance each other. The Ocean may "breathe" more O2 than trees, 
but it is within the tree "breathing" that we have reason to suspect an 

Source: "Biogeochemistry: An Analysis of Global Change" 2nd Ed. by W.H. 
Schlesinger, 1997. (a classic text on the science of global biogeochemical 

Rob Scott
Urbana, IL

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