Hah, ran across this chart; currently, carbon dioxide consists of .038% of Earth's atmosphere-- and man's contribution in the entirety of his time on the planet is 14%, of that .038%.

At its peak, carbon dioxide was almost 9% of the atmosphere: that's 237 times the present level-- and no Venus-style run-away "greenhouse effect" took place, as evidenced by the fact that we're here now.

Bozo O'Rourke, Commie Bernie and his motley pals tell us that if we obliterate the world's economy and plunge the very least fortunate of us into desperate, crushing poverty, the black line on that graph will basically only go up one fifty-fifth of a pixel, versus one fiftieth.

Meanwhile they had tens of thousands of hysterical kids engaging in truancy from school, over... nothing.

And all of this is assuming that carbon dioxide isn't a trailing indicator of temperature levels, caused by variations in the sun's activity. It's also not taking into account the role of water vapor: even the "one fiftieth of a pixel" estimations assume that water vapor is a multiplier-- which is unconfirmed.