Fleeing earth isn’t the answer anytime in the next 500 years. It might be an answer for ultra billionaires who have the money to create a biosphere, but not for most of us. The answer is to gradually reduce population and transition to an economy in which each and every one of us several billion souls consumes substantially less. What I fear, though, is that the elites will see this as conflicting with their personal interests and double down on an economy that is ever reliant on production and consumption. Their solution will be to radically reduce the population of those who stand in their way.
No, that’s the strawman answer Republicans create to make us afraid of a future so bad that we refuse to even consider changing our current system. The actual solution is to continue to develop technologically in order to produce more efficiently with less harmful impact, and to ensure that the gains from this increased productivity are shared more equitably among all parts of society.
This kind of ridiculous panic about the human population reminds me of the (fantastic in most other ways) Asimov novel, The Caves of Steel, where Earth’s population has grown so much that the only way to sustain it is by feeding everyone yeast grown in vats, and the atmosphere is so poisoned that all humans live beneath domes. The Earth’s population, the unimaginably large mass of human lives that brought our ecosystem to its heel in such a dramatic way? 8 billion.
Not even for the billionaires. We don’t even know how to create a functioning biosphere that could sustain us. And if we did, it would still be easier to create one here.
Any damage we manage to do to this planet is massively unlikely to leave it in a state as inhospitable to human life as the already-existing state of any other planetary or lunar body we might conceivably get to. The only possible exception to that wouldn’t be us; it would be a meteorite strike so massive that it either split Earth apart or turned it molten.
There are good reasons to explore space, and maybe even to start human colonies elsewhere. But ‘we’re screwing this place up so we need to be able to go somewhere else’ isn’t one of them.
I’m not familiar with anything. There are some efforts, though, to make the harvested biomass economical - or at least less of a loss - to remove. But ultimately, someone’s going to have to go in and remove it.