[no_more_death]

Well, currently birth rates are declining not because people have too little, but because they have too much. We only want as many children as we can have without degrading our quality of living or theirs. E.g., a typical family cannot have more than two children because they cannot afford to have the same quality of housing and give the child the same quality of education. Plus, having children gets in the way of people doing what they want to do.

The level of inefficiency and unused territory in the world is mindboggling. I think the national park system ties up one-third of land in the US -- land that's absolutely unused. If worst comes to worst, I'm guessing we will start cutting into that resource little by little. It would take many, many decades or centuries to exhaust all of that.