Different Geomagnetic Pole Shifts
Date: Fall 2012
I understand that the magnetic North Pole is thought to be shifting at a much faster speed (at least 3:1) than the magnetic South Pole. Is this because the earth is somewhat ellipsoid and/or because it may be more turbulent at the top due to the molten inner core moving more rapidly than what is happening at a more sluggish bottom, and what effect might this disparate rate of change have on our climate?
Earth's magnetic field has flipped several times during it's time. There was little change noted in the fossil record.
The magnetic field is formed by a geodynamo, the result of convection currents of the molten iron:nickel layer, 4000 miles to the interior. The convection movement generates a current which, by Faraday's law of Induction causes a magnetic field. The notation of North vs South is man derived, the Earth really does not care too much which is which.
The magnetic field is useful in deflecting ionizing particles toward the poles, providing the particles a limited area on Earth. There appears to be little consequence as to which way North or South is directed.
The best advice I can locate indicates little climate change as the result of a magnetic directional change. However, a change in the total magnetic field may be difficult to estimate. These references may help you.
G.A. Glatzmaier and P.H. Roberts, (1995) Phys. Earth Planet. Inter.,"A three-dimensional convective dynamo solution with rotating and finitely conducting inner core and mantle," 91, 63-75.
Peter E. Hughes, Ph.D. Milford, NH
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