[andrewas]

Pole shift can happen. AFAIK theres no way to predict it.

I dont know enough about it to say what damage would be done though. Monitor colours would go all weird, magnetic navigation would become impossible, minor effects like that. Nothing that would cause us to be totally screwed that I can see.

And if you think magnetics is a miracle, what about gravity? Or radio. Invisible things that cannot be seen, but have a massive effect on our lives.