David Christian had an interesting talk with a Big History view of the universe. He had the long view of the universe, life on earth, humanity and human civilization. His point was that the collective intelligence of humanity can be used to make a civilization with a smaller environmental footprint while still making everyone happy.
I note that when two aspects of his talk are combined, that the dinosaurs were killed by an asteroid and humanity needs to have a longer view. 100 years ago we were just developing airplane technology, but within 80 years there was extensive global travel on 10,000 planes moving 100 million people per year. The same shift will be happening for space travel. There has been a lag in the development of true space capabilities, but those capabilities are coming. There are several possiblities for spaceplanes.
True industrialization of space will enable large scale migration. The solar system has one million times the resources of the earth and billions of times the energy. Bigger and bolder solutions are possible. If humanity remains exclusively on the earth then we are just as vulnerable as the dinosaurs regardless of how light and sustainable the footprint is. True space capability is needed for humanity to transcend current problems. I would argue that many of the problems of powerful technological weapons and biosphere impacts are because humanity has outgrown the earth and only needs to have part of its footprint here.