There will be lots of wars in the future because of the spreading atheism. Militant atheists (for example: Mao, Stalin) are known to be the most blood thirsty savages ever seen. The more atheists there will be, the more war and chaos they will bring with them.
If you say Stalin and Mao, first thing comes at my mind is communism, not atheism. So I think you missed a point here, there were many brutal wars fought in the name of religion, and Mao and Stalin's wars was not one of them.