Have you looked at this data?
I was not impressed with the rather coarse graph "adapted from [the] IPCC" showing GHG concentration and temperature correlation over the last 200,000 years. The US Global Change Research Program has this interesting graphic (click on graph for larger version) based on Vostok ice core data, which reveals much more detail. Unless I am reading it incorrectly, it suggests that over the last 420,000 years, temperatures changes have generally preceded major CO2 changes. Look closely at the peaks and troughs in the first and second plot lines - sometimes the lag is very slight, but it is there. CO2/GHG seem to have been the effect, not the cause, of temperature changes overall in the past.