RE: Number of carbon atoms in the Earth's biomass

From: Amara D. Angelica (amara@kurzweilai.net)
Date: Sun Jul 13 2003 - 02:46:48 MDT

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    Hal, Spike, and Jeff: thanks. Here are the calculations confirming your
    number. If anyone sees an error in these numbers, please let me know.

    Average atomic weight of carbon (adjusting for isotope ratios): 12.011

    Moles of carbon in biomass: 829 x 10^15 grams/12.011 = 69 x 10^15 mols

    69 x 10^15 x 6.02 x 10^23 atoms (Avogadro's number) = 4.15 x 10^40
    carbon atoms.

    However, the report also states: " FAO-UNESCO values indicate that the
    amount of soil organic carbon in the world is about 3000 x 10^15 g," so
    I'm confused.

    > -----Original Message-----
    > From: owner-extropians@extropy.org
    > [mailto:owner-extropians@extropy.org] On Behalf Of Hal Finney
    > Sent: Friday, July 11, 2003 11:17 AM
    > To: extropians@extropy.org
    > Subject: RE: Number of carbon atoms in the Earth's biomass
    >
    >
    > Amara Angelica writes:
    > > Does anyone have data on the total number of carbon atoms
    > currently in
    > > the Earth's biomass and the rate of depletion?
    >
    > I googled a good web page,
    > http://www.icsu-scope.org/downloadpubs/scope13/chapter06.html.
    >
    > Some possibly surprising facts:
    >
    > 99% of the biomass is in plants, not animals or
    > microorganisms. 99% of the plant biomass is in land plants,
    > not ocean plants.
    >
    > The total biomass is 829 x 10^15 grams of Carbon. If my
    > calculations are correct this is about 4 x 10^40 Carbon
    > atoms. Of this the largest portion is in tropical rain
    > forests, about 40%.
    >
    > Although the web page above has enormous detail about
    > forestry operations, it is a little hard to pull out a
    > summary number. Section 6.3.1 gives a 1977 estimate that the
    > rate of deforestation is about 1.1 x 10^15 g/year, with
    > reforestation at about 0.3 x 10^15 g/year, for a net loss of
    > 0.8 x 10^15 g/year.
    >
    > It's not clear if this is the same "grams of Carbon" used
    > elsewhere in the report (versions "grams of wood") but
    > assuming it is, that corresponds to a loss of about 0.1% per
    > year, or 4 x 10^37 Carbon atoms per year, which would also be
    > about 10^30 Carbon atoms lost to biomass per second.
    >
    > All these numbers are very rough estimates.
    >
    > Hal Finney
    >
    >

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