Spaceflight

This argument assumes that space travel and colonization as well as developing sustainable livelihood on Earth are mutually exclusive, but it could be argued that they are symbiotic. Living in space pushes our abilities to be completely sustainable, from energy conservation to complete resources recycling. Not only does being in space require us to better utilize our resources, but it also allows for easier access to resources that are burried deep within our planet. On Earth, we cause great environmental disturbances to acquire rare earth metals while many asteroids have them at or very near the surface. There's also a developing industry of zero-g (micro G) manufacturing that is much more efficient for composite materials and medicines. There's also the Overview Effect on a majority of people that go into space that mentally changes their view on both the planet and humanity.