Re: [asa] CO2 content

Burgy wrote:

> Attached is a chart showing CO2 content over time.
>
> The claim is that this shows rising CO2 is not a problem.
>
> What is the rebuttal to this claim?

One of the papers I heard at the AAAS meeting in Boston a few months ago
presented the latest update of this particular issue. One of the puzzles was
the apparent time shift between that huge shift in CO2 level and a global
temperature shift that was offset by a few million years. These authors
showed the difficulty in measuring CO2 for this time period--they usually
use proxies that infer CO2 content of the oceans and then from that infer
atmospheric concentrations. They claimed that they did a much more rigorous
analysis that for the first time took into account the latitude-dependence
oceanic coupling with the atmosphere, or something like that. They claim
that the major discrepancies between the CO2 shift and the global
temperature shift were largely resolved.

The other point they made is that the CO2 relationship to global temperature
is complex. Warmer temperatures can cause an increase in CO2 and vice versa.
Both effects are seen in paleoclimatology, apparently. That's why it's
necessary to dig deeper and figure out what the causes are for any
particular era.

For our current phase, the C13/C12 ratio clearly shows that the rise in CO2
is due to combustion of fossil fuels. The consequence of increasing
temperature is not only seen in models, but can be seen in paleoclimatology
where global temperatures and CO2 levels are well correlated, including the
shift at around 51mya.

Randy

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Received on Sun Aug 24 08:15:52 2008