On Tue, 10 Apr 2007 18:04:42 -0000, Jim Logajan
wrote:

The ratio of carbon isotopes C-12, C-13, and C-14 found in fossil fuels and
the ocean are known and provide tell-tale "signatures". The ratio of those
carbon isotopes in the atmosphere have been measured with respect to time
and the isotopic evidence indicates the increase of carbon dioxide in the
atmosphere is most probably due to the burning of fossil fuels.

Carbon 14 comes into existence when Nitrogen atoms in the atmosphere
get zapped by neutrons from the sun. These Carbon atom isotopes are
incorporated into plant material by photosynthesis. But it breaks down
over time and there is little left over 40K years.

So, Carbon Dioxide from a volcano will have no C14. Carbon Dioxide
from coal and oil which are hundreds of millions of years old will
likewise have negligible amounts. You cannot tell one from the other
by C14 measurements.

CO2 from burning trees or rotting vegetation will have measurable
amounts.

So, please explain how one can tell the difference between coal and
oil and volcanic CO2? The presence of C14 in CO2 can only tell us that
it did NOT come from either, but instead from something more recent.

Don



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