Magnetic field: Earth vs. Mars

[tagryn]

This gives a good explanation why a weakening of the Earth's magnetic field would be disastrous, seeing as what it did to Mars: basically, the atmosphere of Mars is blown away by the solar wind, since there's no magnetic deflection of the solar wind as we have on Earth. The relative weakness of Mars' magnetosphere is also a major obstacle to terraforming Mars.

So, is this something to worry about. Well, as with much of science...the answer is "maybe". Such weakenings/reversals tend to be long-term processes that will affect none of us living today, assuming it isn't affecting things like global warming and other things which react to solar energy changes.