I'm an atheist, and in some ways I wonder if atheism could improve the world, but I think it really depends on the person. I do the right thing because it's the right thing to do, and I cannot escape the feelings I have when I hurt someone else. I want to see that others are happy. I see that morals are the best way to enjoy one's life and help other life prosper.
Another atheist might say, "There's no god in the sky watching me, I'll do what I want."
Yet theists will follow a similar pattern. Some will be scared into doing the "right" thing. Some will believe that God is love and be inspired to do charitable works because of that. And, some theists, believing that what they do is the will of God, will strap on a bomb and kill 30 people...or thousands, like 9/11.
Belief in God is not necessary for morality.
James