We are in that temporary zone for quite some time already, and all we need is 100~200 years more until we can get colonies on other planets. If by some miracle

We are in that temporary zone for quite some time already, and all we need is 100~200 years more until we can get colonies on other planets. If by some miracle human population was reduced to say 1bln it would make space colonies much less likely, and we'll slowly eat out our petri dish without a chance to enlarge it.