This is all monumentally complicated question, which (in line with my Existential/Nihillist/Camus-like-Absurdity beliefs) in my own view has a fairly simple answer. I wrote this a while ago, thusly:
"Human intelligence is self-defeating. Because of the nature of our 'intelligence, our special kind of 'self-awareness' and curiosity, and our drive to explore, ask questions that don't have answers, over-populate, the selfish gene, morality (for our own ends), is destined to self-destruct. Human intelligence is unable to stop it's downward spiral into self-destruction, because of it's very nature. The human race is a rapidly multiplying tumor on the planet. People may point to art. beauty, love, acts of complete sacrifice, but even these (if they too do not contribute to the final downfall, which they probably do) pale into insignificance to the descruction we are causing to ourselves and everything around us. And all of this in a staggeringly small scale of time. Even if we managed to populate every planet in the universe, there would be a limit to our expansion. Unless we come to some kind of 'enlightenment' that is at the moment beyond us, we are ultimately doomed But, as Camus said, the absudity of this state of affairs does not mean that we should all kill ourselves or go and live in a cave. We should just accept this life and all it's suffering, and do the best we can for ourselves and others, in the time we have."