The "hockey stick" chart is one of the central features of the Global WarmingTM theory. It alleges that global atmospheric temperatures have sharply increased in recent years as a result of increased atmospheric CO2.
This article reveals just one of the problems with that graph. The same computer program was shown to produce the characteristic "hockey stick" shaped output regardless of what data was input! It's essentially worthless.
I caught that after I posted. The fact is, CO2 is, chemically, a "greenhouse gas" BUT-not nearly as potent of one as the enviroweenies would have us believe. I've read plenty of articles about the potential terraforming of Mars. In those articles, they mention increasing Martian CO2 by amounts a hundredfold of what Earth has that would increase temperatures 10 degrees or so. So a 50 PPM increase on Earth isn't going to make any discernable difference at all.