Quote:
Originally Posted by moyself
You forgot one thing... this is about 5% of the CO2 only. Since CO2 makes up only about .0360…
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It’s important not to confuse carbon with
, or fraction of gasses by volume with fractions by mass.
A single atom of carbon masses about 12 AMU, while a single molecule of
masses about 12 +16*2 = 44. So a release of
of Carbon (the 1994 value for fossil fuel and cement) equates to about
of
.
The total mass of the Earth’s atmosphere is about
. About .00015 of it,
is carbon. About .00055 of it, then,
, is
.
Regardless of whether carbon or
is measured, the amount added to the atmosphere every year is about 0.29 of the amount in the atmosphere, which is to say that an “average” molecule of [ce]CO2[ce] remains in the atmosphere for about 3.5 years.
The
(1994) to
(present day) of carbon from fossil fuel and cement is roughtly .025 and .036 of the total carbon added to the atmosphere every year.
Sources: wikipedia articles
“Earth’s atmosphere”,
“carbon cycle”, and links from those articles.
The basic problem, I think, with concluding that human-generated carbon emissions are insignificant, is that the other major carbon emitters – vegetation, at about
, and the ocean, at about
, are also significant absorbers – about
for vegetation and
for the ocean. If land vegetation or marine biological and chemical sources increase, not only their emissions, but their absorption, increase. This is not true of the usual human sources.
Looking at their net emission and absorption, vegetation is about
, the oceans about
, and human sources about
.
A serious scientific question about atmospheric carbon quantity is whether natural sources – most promisingly, the ocean – can adapt to absorb the increased emissions from human sources. The scientific consensus is that, without artificial encouragement, it cannot.
So the major scientifically credible approaches to controlling atmospheric carbon consists of:
Some have suggested that if the amount of carbon in the atmosphere is simply allowed to increase with no artificial effort to reduce it, natural sinks such as vegetation and the oceans will increase their rate of absorption to keep the amount at or near the present amount. However, these suggestions have not been supported by experimental evidence, and are contradicted by biological data and experiments that indicate that these sinks require more than just additional
to increase their rate of absorption – basically, they would require more nutrients, which can only be supplied artificially.
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