...and here, as far as I am concerned, is the most interesting part:
You see the red line? That's CO2. Carbon Dioxide. And as you'll note, as a rule, CO2 does not rise, followed by temperature; no, what happens is temperature rises,
then CO2 rises, and then temperature falls, followed by CO2 falling.
In other words, CO2
lags temperature, not leads it.
This would be indicated by the blue line (temperature) falling, then the red line (CO2) falling to the right of it, which would be later in time.
You can clearly see this at -375000 years, -325000 years, -240000 years, and -100000 years. For all four major temperature cycles, CO2 lags temperature, not leads it.
These are objective facts - neither side of the AGW controversy can deny them.
Now, it seems to me that there are two ways to read this graph correctly.
The first is that CO2 is a consequence of the warming process, in which case it is not very relevant.
This is primarily indicated by the fact that CO2 increases occur after warming; not the other way around; it is also indicated by the fact that temperature falls sharply while CO2 is still high, which clearly shows that
high levels of CO2 alone cannot account for holding global temperatures up.The other is as the AGW position partially claims, where CO2
drives the range of global temperature.
In that case, the historical record
repeatedly demonstrates that excessive CO2 in the atmosphere leads to rapid global
cooling, at which point the CO2 (perhaps generated by plants and animals which cannot survive in cooler temperatures) eventually falls off.
Historically speaking, the data contradict the direction of the AGW claims. Either AGW is outright invalid (first case), or the risk is actually cooling, not warming (second case.)
What you cannot do, however, is read this graph to support the idea that high CO2 causes warming. This is because it clearly shows that while CO2 remains high, temperatures fall anyway, and
then CO2 drops.
Looking carefully at the graph, something else in the climate was visibly driving temperature far more powerfully than CO2 does; the most likely candidate for this is the evaporation / precipitation cycle (E/P cycle), which accounts for significant heat removal from ground level by the mechanism of dropping cool water and evaporating warm water, then radiating the heat in the evaporated water out into space. Also by the fact that unlike CO2, the E/P cycle is highly dynamic - as temperature rises, the E/P cycle accelerates to move more water in any area where there
is water.
). 
