|Quoting BHXFAOTIPYYC (Reply 6):|
I never knew this... but how does it change? North is still north, and everything else is still in it's relative position
It is a little confusing, if you followed magnetic north on a compass you wouldn't actually end up at the north pole, just somewhere nearby, and where you end up would change over time, but only slightly.
What may of happened recently is that Earth's magnetic field has moved by half of 1 degree but if that turns a runway heading from 244.5 degrees to 245.0 degrees then it will redesignate its runway from 24 to 25. Obviously this will only affect very few airports as a change from, say 240.5 to 241.0 degrees will not change the designation 24.
What is even more alarming is every so many hundred thousand years or so the magnetic poles flip over, meaning a compass would point South!