Thanks Mactombs, that's great info that I was thinking of looking up myself.
I knew the poles commonly (in geological time) reversed themselves, so I wasn't really perturbed by the 2012 prediction - though it's good to know the facts.
Yes, thanks for posting this. It's good to see some down-to-earth info on this subject. But I doubt this will convince "the others" [;)]
Here is a condensed form of some research I did on pole reversal (main sources from Canadian studies and NASA). I find there is a lot of hype about pole reversals / magnetic fields, but most of it also seems to be poorly-informed...
The pole was located for the first time in 1831 by James Ross in the arctic (during which his ship was stuck in the ice for four years). No one returned until 1904 when Roald Amundsen found the pole again; he also found that it had moved at least 50 km since Ross's time. The pole kept moving throughout the 20th century, going north at an average speed of 10 km per year, but recently accelerating to 40 km per year. So far during the last century it has moved 1100 km. At this rate, it will reach Siberia in about 50 years. Compass needles in Africa are drifting about 1 degree per decade. Globally, the magnetic field has weakened 10 percent since the 19th century.
This leads to the issue of complete pole reversals.
According to the magnetism of ancient rocks, pole reversals are unpredictable. Their intervals of occurance average about 700,000 years between them. The last reversal happened 780,000 years ago. There have been over 400 reversals in the last 300 million years. When the poles reverse, however, the magnietic field does not vanish. The magnetic lines of force will become more twisted and tangled, and magnetic poles might pop up in unusual places, but the field will still protect the earth from solar radiation.
Is the current activity unusual? No. The magnetic field is increasing or decreasing all the time. Even if the present trend continues, the poles will not be mid-way through a complete reversal (during which time the magnetic field will be reduced 10% - 25%) for about 1,500 years (with a possibility ranging between 8,000 and 1,000 years). Many researcheers believe that the poles will not reverse at all, but restabilize (as it has many times in the past).
What about the strength of the magnetic field? Is it growing weaker? Yes. But also consider this: the present-day magnetic field is much stronger than normal (8 × 1022 amps × m2), which is twice the million-year average.