from what i hear and understand this is bound to happen, one day someone will take a compass and will find north pole needle pointing to the place where south pole is today... unfortunately there are bound to be specific eras while this south-north exchange takes place, in which the magnetosphere of the earth will be considerably weaker than it is today and that meaning along with the human aided corrosion of the earth, this planet will really be a life threating place. how do you think humanity will take this catastrophy when it befalls upon us?