"He can't agree with himself. Half a billion tonnes, or half a trillion? Hey, a thousand times anything is nothing to a AGWist!"
At which point? Sounds like a pointless nitpick on a slip of the tongue somewhere. Care to address his arguments or just want to nitpick?
"We've had much, much higher levels in past without catastrophe."
Who's "we"? c02 levels haven't been at today's levels since millions of years before homo sapiens existed. Agriculture and complex human society has only been around for roughly 10,000-20,000 years, during which time C02 and temperature have been remarkably stable.
So if you mean "we", the planet, then your point is correct but rather meaningless. If you mean "we" humans, then you're wrong.
