may or may not come as a surprise to you to learn that the Earth's
geographic north pole and its magnetic north pole aren't in exactly
the same place. In 2007, the two poles were about 800 kilometers
apart. Now located in the Arctic Ocean just north of Canada,
the north magnetic pole is moving northwest toward Siberia
by about 50 kilometers each year. The south magnetic pole is
moving too, but at a much more leisurely 5 kilometers per year.
These movements are a result of irregularities in the flow
of the molten iron and lighter metals in the Earth's outer
core. Eddies and swirling currents in the outer core lead to
movement over time of the magnetic poles on the Earth's surface.
the past few decades, stronger eddies and currents in the outer
core actually have weakened the Earth's magnetic field. If the
field's overall strength keeps weakening, it will reach zero
in a few hundred years. It is not clear if this recent weakening
trend is a routine variation that will reverse or whether it
will lead to a full-blown reversal of the Earth's magnetic field—something
that happens on the order of every 250,000 years (but that number
is misleading because there is a great deal of variability in
the amount of time that passes between reversals).
Sid. 2007. North by Northwest. Science News, vol.
172, p. 392-394.
source: Acute accent, http://acuteaccent.com/geographic-north-pole-and-north-magnetic-pole/)
dots denote the pole's movement since 1831. Blue dots are direct surface observations and red dots are from models
using satellite data. The green dots indicate the pole's future
location, if its current rate and direction of motion continue.