"So....what was the CO2 reading 10 years ago, 20,and 30 ago?"
It doesn't matter. Currently, the natural cycles (e.g., sunspot, southern oscillation) dominate ANY effect man has. VEI6 or > volcanic explosions high in sulfur dioxide would really put us in the cooler (> -2C worldwide).
Days of the dinosaurs? Oxygen was 18% of the atmosphere in the age of Dinosaurs. A lot of Oh-2 was tied up in carbon dioxide. Yeah, earth was a warmer place. You would need to burn up essentially most of the coal, oil shale, oil, gas and control absorption of carbon dioxide into the ocean to get you there. It would also help to get rid of Central America so the oceans can help more efficiently distribute heat to help the process along.
Get the feeling this whole manmade global warming thing is a tad premature? Cleaner, renewable energy is the issue. Manmade global warming is BS.
Oh, if you really want to do something about global warming stick a hose up your @$$ and feed it into a condenser to pull the methane stream out of your flatulence. Methane is four-times more effective at trapping IR (heat) in the atmosphere than carbon dioxide. Go chase some dairy and beef cows around and do the same.