Question

Is there any scientific data that shows the earths magnetic poles are shifting faster over the past decades? When was the last magnetic polar shift on earth? If we think it happens in approximately 1 million year cycles, would that not be the pertinent question? If the earths magnetic poles shifted significantly or reversed, does anyone know for certain what the effects would be on the surface of the earth?

The magnetic poles are always shifting slightly, in response to both internal variations in the Earth's dynamo and to changes in the Earth's magnetosphere that are triggered by the Sun. There is no indication that these magnetic variations have increased recently. Wikipedia has good articles on Earth's magnetic field and on geomagnetic reversals. These reversals are not periodic; sometimes in the past the magnetic polarity has been constant for tens of millions of years, other times there have been reversals as often as 100,000 years. The last such event, called the Brunhes-Matuyama reversal, occurred about 780,000 years ago. Thus we have never witnessed a field reversal, but we don't expect many effects on the surface, although obviously the structure of the Earth's magnetosphere would change greatly during the transition.
David Morrison
NAI Senior Scientist
July 14, 2008