Jonah, count me with the group that sees three hundred million as a thoroughly miserable milestone. Malthus may have underestimated human ingenuity (he wasn’t a fortune-teller), but it’s no less a mistake to overestimate it either. It’s also worth noting that while we can support a global population far larger than anything imaginable a century ago, you don’t have to be a fanatical environmentalist (believe me, I’m not) to believe that it has come at a pretty high cost.