> If we run out of land, we take the sea. If we run out of sea, we take space. And so on. This answer precludes the very real possibility that the necessary te

> If we run out of land, we take the sea. If we run out of sea, we take space. And so on. This answer precludes the very real possibility that the necessary technology advances to "take the sea" or "go into space" don't come in time to be useful. Any plan that includes "things that haven't been invented yet" isn't a real plan, it's wishful thinking.