To me, “sustainability” means a situation in which your descendants are able to confront their own problems, rather than the ones you exported to them. If people a hundred years from now are soberly engaged with phenomena we have no nouns and verbs for, I think that’s a victory condition.
On the other hand, if they’re thumbing through 1960s Small World paperbacks and saying “thank goodness we’ve finally managed to pare our lives back exclusively to soybeans and bamboo,” well, that’s not the end of the world, but it’s about as appealing as a future global takeover by the Amish. [From Why We Love Bruce Sterling]