Andrew Gabriel wrote:

That's the easiest thing of all to explain. The largest
resoviour of mobile CO2 is the sea. When you warm the sea,
the solubility of CO2 reduces raising the partial pressure
in the sea, which forces CO2 out into the atmosphere to
maintain equilibrium. When the sea cools, the reverse
happens. You would absolutely expect the CO2 levels to
correlate with temperature. More recently with more
accurate dating, there's some evidence that the CO2 level
correlation lags the temperature changes by some hundreds
of years, which also ties up with how long the sea is
expected to take to warm and cool under the influence of
atmospheric temperature changes. This would also point to
the CO2 level change being an effect of temperature change,
and not the cause.

I think this is one area where the media in general let everybody down.
In their attempts to make the subject easy to understand they tend to
give the impression that there is a straight causal relationship between
CO2 and temp. The reality is as you point out, a much more complex
closed loop system, with phase shifts, and feedback effects and delays
in both directions. So CO2 change can be a result of temperature change,
at the same time as being a re-enforcing influence on it.

--
Cheers,

John.

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