Reply #23: "Replace" is a strange word to use in this context.

[Silent3]

Atheism isn't a replacement for religion, it's just a lack of it. To get really technical about it, atheism is just a lack of belief in deities. It's at least conceivable (I'm not aware of any real-life examples) for an atheist to believe in a godless variety of supernaturalism and to build a religion around that.

That said, I have a hard time imagining the kind of cultural shift it would take to turn atheists into a world majority. The most atheist country in the world right now (according to the stats in the OP) is Sweden at 64%, but no other country mentioned goes over 50%. Even if the pattern we see -- that increased education, safety, health and economic security generally lead to less religion -- is a pattern that would generally hold true, I wouldn't feel confident in predicting that all of those things will only increase in the future.