Atheist or faithful, it is incumbent on all of us to celebrate humanity and seek to fulfill the promise of our species, dosed with humility and gratitude.
Obsessing about the evils wrought by mankind, our various failings, and positing a dreary future for all is has some value in that it keeps us all aware of the problems. But suggesting that there is no hope is a waste of time. If you truly believe the worst and cannot convince yourself of the best, my only advice would be to dig a hole, line it with concrete, fill it with food, water and comic books, and await Ragnarok.
But really, we’d rather you join us. We’ve got a world to fix, after all.