Much as I'd like to think humans-in-space in large numbers will become a reality any time soon, I don't see it happening in the kind of time frame it offsets the dangerous growth curve we're on.

The cost to keep one human alive in space is logistically incredibly expensive. It'll get cheaper the more infrastructure we put up there, sure, and eventually we may see space-based colonies become self-sufficient. But I don't see it happening any time soon.

Meanwhile, current projections suggest that ~2050, human population is going to get very hard to maintain. Even if we could get 100,000 people living in space by then it would be a drop in the ocean.