I have heard on more than one occasion that in the year 2012 the earth’s magnetic poles might switch.
Is this really true? And if they do switch, what will that mean for us? Will it just be that all our compasses be wrong? or is it worse than that?
The 2012 thing comes from crackpots; don’t listen to them. Nevertheless, there is good geophysical evidence that the Earth has reversed its magnetic polarity many times throughout its 4.5 billion year history, with a widely varying frequency. And there is at least some evidence that we may be currently undergoing such a reversal. A complete reversal is expected to take a few hundred years to complete, so I don’t think we have any immediate worry.
The Straight Dope - Are the earth’s magnetic poles shifting?
http://www.straightdope.com/columns/read/2689/are-the-earths-magnetic-poles-shifting
Hey cool there’s a column on it!
Strangely I never thought to search for a column before I asked the question…
The coolest part will be seeing auroae(sp?) all over the world just before the switch.
Assuming we survive the hundreds of years of high-energy cosmic ray bombardment. 
Almost: Aurorae.
The flipping process in the Earth is very similar qualitatively to the reversal that occurs every eleven years in the Sun, causing the solar cycle. In the process of flipping, the field will get much more quadrupolar and octopolar and n-polar, getting messier and messier, before re-aligning into a nice, tidy dipole. The biggest difference between the Sun’s dynamo reversal and the Earth’s is that the fluid responsible for the dipole in the Earth is much more viscous than in the Sun, which results in both a longer interval between flips and a less predictable interval.
So if the poles really did flip, how would it affect human life?
The article says that pole reversals have not historically coincided with mass extinctions. We’ll have lots of disruption in the power grid and with other technological stuff, some species that rely on the Earth’s magnetic field to navigate or breed will be out of luck, but we’ll probably be ok.
the 2012 thing comes from the old Mayan calander that stopped at their equivalent of the year 2012, most likely because whomever made it either ran out of space or thought to himself “this is like 2000 years from now, that’s probably good. Time for some lunch…” or the equivalent thereof (no, I don’t know when the Mayan calender was created, but given they were one of the more ancient mesoamerican civilaztions I just took a guess at it).
As for how life will change… we humans don’t depend on the magnetic field for much of our basic needs, but it will throw a lot of wild life into confusion and there might be some extinctions of, say, fish or turtles that require magnetic senses to find their breeding grounds.
What I got from a previous thread on the matter was that the Mayans pretty much ran out of numbers at that point and just decided to start over every X amount of days (the calender that specifically ends there is the one that doesn’t count by years or months or whatnot, but counts every single day until the end of time/their number line as a new/unique number iirc).
Except for that trifling thing about lethal cosmic ray bombardment. Not getting fried by radiation is a pretty basic need on my list.
It’s not THAT bad; otherwise there would be mass extinctions with every reversal. You’ll probably get an upsurge in things like cancer though, assuming we haven’t cured it by then.
OK, well, not getting cancer is also fairly high on my list.
Is there any likelihood of problems with electronic equipment during such an event? - if all the gadgets and gizmos stop working for a centurey, that might have quite a significant impact to humanity
The magnetosphere isn’t really strong enough to deflect high energy galactic and extra-galactic cosmic radiation. The Earth’s thick atmosphere absorbs and protects against the most hazardous cosmic ray bombardment and daughter products (x-rays, gamma rays, neutrons), and in any case the high energy extra-solar particles are generally too energetic to react with a human body in significant quantities (at least in short term exposure). The Earth’s magnetosphere protects against high fluxes of charged particles emitted during solar flares and coronal mass ejections; a loss of the magnetic field will increase radiation, primarily from interactions between charged solar particles and the upper atmosphere, but it is hardly the case that anything will get fried; it’s just that the amount of background radiation will increase somewhat as charged particles are not deflected by the magnetic field or captured in the Van Allen belts.
Crackpot theories about the end of the world due to polar reversal rarely rise above the level of technical veracity most suitable to Coast to Coast AM. Reversals do occur, but there is no evidence they they have significant, detrimental, long ranging effects on the ecosphere.
Stranger
So I WON’T be turning into the Incredible Hulk?
Bummer