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Earth's Magnetic Field Weakens 10 Percent
caryw writes "Interesting story from the AP. 'The strength of the Earth's magnetic field has decreased 10 percent over the past 150 years, raising the remote possibility that it may collapse and later reverse, flipping the planet's poles for the first time in nearly a million years, scientists said Thursday. At that rate of decline, the field could vanish altogether in 1,500 to 2,000 years, said Jeremy Bloxham of Harvard University. Hundreds of years could pass before a flip-flopped field returned to where it was 780,000 years ago. But scientists at a meeting of the American Geophysical Union cautioned that scenario is an unlikely one. "The chances are it will not," Bloxham said. "Reversals are a rare event."'"
I didn't think it was too "alarmist" as towards the end they talk about the only major negative effects of a weakened magnetic field and eventual switch is a slight increase in cancer (compared with all the cancer in the world as we know it today.) It also presented the possibility of having more than 2 poles, and a positive effect of the was having the auroras being visible all over the Earth. I showed this in my Earth Science classes this weeek, as we just started talking about how magnetic reversals are recorded in igneous rock, and is one of the pieces of evidence for sea floor spreading and plate tectonic theory.