"Dan Luke" wrote:
BTW, Tony, what about this post from Barrow?

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Regarding the environmentalists' concern over CO2, here are some facts
nobody argues with:
[...]
5. There were 2,400 billion tons of CO2 in the atmosphere in 1950;
3,600 billion tons now, give or take a psi or two--.

6. Human activity currently releases 6 billion tons of CO2 per year.

7. Non-human activity (oceans, trees, Pinatubo, Mauna Loa, etc.)
releases 200 billion tons of CO2 per year--.

Now compare fact #5 with fact #6. Simple division tells you that if
every molecule of human-released CO2 at the current rate of production
stayed in the atmosphere, it would take another 200 years for the
post-1950 change to be matched.

The evidence is clear that something is wrong with the above claims.

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.

(The first person to use isotopic ratios to determine the source of
atmospheric carbon dioxide was Hans Suess as far back as 1955. In
particular, the dilution of C-14 due to fossil fuels is known as the Suess
Effect.)