North and South is a Geographical term, referring to the two poles of the earth's rotational axis. In layman's terms, the North is to the left when facing in the direction of the Earth's rotation, and South is to the right. The magnetic poles have simply been named in their relation to the geographical poles. Should the polarity reverse all that needs to be changed is the naming convention, from that moment onwards the former magnetic South becomes North and vica versa, and everything is back to normal.