Long ago, Uncle Arctic and Aunt Arctica were married, and the world was warm all over. They eventually had irreconcilable disagreements, however, and therefore had to go their separate ways and be great distances from each other --- so far apart, in fact, that they actually retreated to opposite sides of the Earth, and so that's why it's now so cold in those areas.

A:dude, Anatidaephobia is the coolest phobia ever!
B:quack!