Atheism, a dangerous idea?

I've seen it mentioned several times that a Christians morals can be debated based on what is written in the bible. Personally I'd much prefer (and feel much safer) if a persons morals were debated based on the effects they have on the people around them rather than what is written in a book. Morals should never be divorced from people, they should be based on them. They're not something to be leared like a times table, they're meant to be learned by living them and understanding the consequences of different actions (and I'd imagine that's how most peoples morals are formed). But then that's just my personal opinion