Originally Posted by
tyrion
Humans can't live sustainably on a space station, and there is a practical limit to population growth on Earth.
Yes, it is fascinating to consider what makes Earth in its natural form sustainable and how changing various parameters alters the feedback cycles that keep it stable.
In general, whenever you reduce resource use/waste by replacing a less efficient technology with a more efficient one, you make the Earth a little more sustainable by preventing waste from spiraling out of control.
Paved infrastructure and development has that potential of spiraling out of control because we don't reforest land after developing it into automotive sprawl. We just keep expanding and developing more land.
So switching to passenger rail, away from driving and flying, would reduce the amount of land and fuel/CO2 wasted on transportation; though buses would also be better than driving and flying.
It's not quite as efficient as putting humans in space stations and totally protecting the natural biosphere from them that way, but as you said that technology is a long way off.
There, now the space station tangent has been brought back around to the topic of the thread, high speed rail.