Is the Magnetic Field of the Earth Weakening?

History channel ran tons of Nostradamus, particularly the end of the world in 2012. They also ran documentaries about things like the magnetic field of the earth weakening. A lot of new age literature wrote about this happening because astrology is a big thing in their sort of circles. The sun rises and falls by different constellations in the sky as it moves through these constellation that rises and falls over the year.