OK, very funny, though a bit tired of an observation. Humans are a disease, humans are a plague, yes yes, we've heard it before and we've seen the terrible things we have been doing, and yet I have to point something out here.
Intelligent life, while admittedly is a potential cause of, is actually the first possible defense that this planet's ecosystem has evolved against an extinction level event.
Stopping a super volcano might still be a bit of a stretch at this current time (give it time though), but the whole asteroid thing - intelligent life actually might have a chance, even right now, of stopping another big whack to the planet.
Think about how the shell evolved: might intelligent life be some kind of earth shell? some kind of life shield?
To be clear, I don't ascribe to some magical teleological aspect of the universe, nor some gaia hypotesis: I'm not saying this is WHY we are here or WHY we were made - but hey, shells evolve big and small - why couldn't we, humanity, become life and earths greatest ally?
Sure, we mightn't, but why we shouldn't nor couldn't?