Mars?

[Aoi Magi]

I am guessing the reason for settling in a different world would be BECAUSE we would have eradicated most of our species by that point and also destroyed most of our solar system.

I dunno - it would seem to me if we had eradicated most of our species (I assume you mean most of H. sapiens), it would take a lot of pressure off the resources we need to live, *and* that we'd have more pressing concerns than getting off of this rock.

I would think that overpopulation would be a huge motivator to find more space. (Though we still have a large number of problems to solve, not the least of which is actually getting there. Then there's the fact that we don't have anywhere to go *to* yet.)

Think of The 100 or Wall-E type scenario, humanity soon will have the capability to sustain life in outer space and colonize other planets (by soon, I don't mean our lifetimes but that of our grandchildren perhaps), but overpopulation or not, the only way we would get our lazy asses off of this rock is if it became totally inhabitable, be it by nature's fury or our stupidity or both. Because other than the survival of the species I don't see any other motivators strong enough to actually lead us away from this rock.