[abefortas]

You're right. That's what I meant by evolutionary suicide, and my argument (well, it's not really mine) relies on all six assumptions, more or less.

Although:

Colonizing space and colonizing space to the point where you don't need to worry about earth's carrying capacity are two quite different things. Energy and minerals might be obtainable from space somewhat soon. But we can't eat rocks or sunlight.

I don't claim population growth will be sustained into the indefinite future. I claim that it will be sustained until it stops, and that how it will stop is a question of serious concern.

As I see it there are several possibilities: 1.Population growth continues apace and, due to reproductive time lag, there are suddenly far too many people on the earth. This has a quite catastrophic domino effect and an appalling number of people, maybe 100%, die. 2.Population slows and then stops, but people's lifestyles get more and more decadent and far too many resources are transformed into far too much waste. Something, or many things, run out and disaster ensues. 3.Both population growth and resource consumption naturally find some sustainable level. Maybe that would be somewhere below where it is now. Maybe someone would invent something fabulous, say a glass elevator like in Charlie and the Great Glass elevator, and there is room for lots more consumption and lots more people.

Obviously, I prefer the third option. Maybe it will be that. I'm just sufficiently unsure to be worried about it.