Actually, the chart would seem to indicate that temperature influences CO2 concentrations, not the other way around. So it would seem that higher temperatures allow higher CO2 concentrations. It may also be that higher average temperatures support larger populations of animals and humans, all of which emit more CO2, but the population increase lags behind the temperature increase by a few years. As temperatures cool down, more deaths of the weak and infirm occur, lowering the populations and decreasing the CO2 output.
That definitely supports theorizing that temperature fluctuations drove CO2 concentrations. I've yet to hear a plausible (or even implausible, for that matter) hypothesis explaining ancient increases in CO2 causing temperature increases. Even though Al Gore and Co. would dearly love people to believe it.
At best (from the perspective of a supporter of man-made Global Warming), this chart shows a possible correlation between temperature and CO2, not a causation. And certainly not that CO2 drove temperature change.
I read somewhere that the oceans are the world’s repositories of the largest amounts of CO2. The warmer the oceans get, the more CO2 they release.
It is actually a function of the solubility of CO2 in water.
In the paleoclimate data CO2 increases lag temperature increases by app. 1,000 years.
See The Acquittal of Carbon Dioxide, http://www.rocketscientistsjournal.com/2006/10/co2_acquittal.html#more for a full blown paper on the subject.
Rising CO2 is a result, not a cause of global warming.