The arguments about global warming which concentrate on the possible lag of
CO2 with respect to glacial recovery, really are irrelevant. The glacial
periods are known to be caused by astronomical cycles, not CO2. The CO2 can
be a factor, but the primary factor is the earth's orbit. The current
situation is that the CO2 has a much higher abundance than would be normal
and this is the most important factor in the climate models.
So those who say that CO2 can not cause warming because it is not well
correlated with glacial periods are off the mark. That is not relevant to
the debate. Any arguments about CO2 have to then be within the
climatological models.
So is there any data which shows an increase in CO2 correlated with greater
warming, which is not connected to the well known cycles that produce
glacial periods? Of course lack of data is not the same as negative data.