[PeaceBeWithYou]

Hmmmm. They seem to be trying awfully hard to tie CO₂ levels and temperature.

I don't see it. There is no correlation.

[Ernest_at_the_Beach]

I don't see it there either.

[Myrddin]

Milenkovich cycles do a better job of explaining the temperature variations on your graphic. Simple orbital mechanics that are completely independent of human activity.

[AntiGuv]

There is controversy about how the research matches up (or doesn't), since it draws on different data in order to extrapolate climactic conditions of the past. In particular, that middle Mesozoic temperature is in dispute, because low latitude data from the Tropics suggest cooling (as shown by the graph) whereas high latitude data from nearer the Poles suggest warming. Also, temperature trends must be discerned from what is ultimately local data, whereas carbon dioxide levels can be determined from what is thought to be global data.

More importantly, this graph shows fluctuations of atmospheric CO2 in the hundreds and thousands of parts per million. Human activity is thought to increase CO2 annually at a rate merely 2 parts per million above what it would be otherwise. There is no real comparison. Meanwhile, there is also no serious dispute that carbon dioxide acts as a 'greenhouse gas' but it is hardly the only factor in determining the global climate. The far more important factor would seem to be tectonics and long-range variations in solar output IMHO.

[AntiGuv]

"climactic" should be climatic.. I always screw that up!

[VOA]

Reminds me of the overlaid bar graphs of annual rainfall and El Nino activity,
as published by The Los Angeles Times last year.
I couldn't see any substantive correlation.
Neither could my younger, smarter cousin...an electrical engineer P.E. that
is still making $$$ running a small Internet database shop.

But I do admit that the NOAA/meterologists did nail the El Nino of 1997-8 (I think
that was the year) pretty well.