system
Given the following post, respond as if you're commenting on Reddit:
human
How much damage would a sudden reversal of the magnetic poles do?

My (somewhat paranoid) sister says that the 2012 apocalypse will happen when the solar system lines up with the galactic core and reverse Earth's magnetic poles. I was wondering how much damage a sudden reversal of the poles would do.
gpt
Polar reversals are not really sudden the way most people would think of them. They happen over the course of anywhere from 1,000 to 10,000 years, so they just seem instantaneous on a geological time scale. It is actually quite possible that one is occurring now, as the poles have moved a fairly significant distance (about 10 miles) in the last few years, and it looks like they may be accelerating. So basically the chances of a sudden magnetic reversal on dec. 21 is essentially nil.

With that being said, as to the damage a reversal would do: very little. There have been thousands of pole reversals in earth's history, and none seems to have caused much of a problem to the life around at the time. There was some speculation that the P/T boundary was partially caused by a magnetic reversal, but that idea has pretty much been scrapped.