Earth's Magnetic Field
© NASA Goddard – CC BY 2.0
We've reported on Earth's magnetic field before, including studies claiming that the planet's poles may reverse at any time and studies saying that Earth is probably not headed for a polar reversal at all. At the heart of these studies is the undeniable, millennia-old weakening trend in the planet's magnetic field, which, depending on your point of view, is either a temporary phenomenon that will eventually reverse itself (as it has in the past), or the harbinger of a cataclysmic breakdown of the Earth's entire magnetic shield and a subsequent flip of the magnetic poles.

The most recent study from the EDIFICE project, a geophysical research initiative based in France, claims we're headed for a cataclysm. According to Dr. Nicolas Thouveny, one of the principal investigators for EDIFICE: "The geomagnetic field has been decaying for the last 3,000 years. If it continues to fall down at this rate, in less than one millennium we will be in a critical (period)."

By "critical period," Thouveny means a point where the Earth can no longer protect itself from solar radiation, which can damage not only the multibillion-dollar satellite ecosystem that makes modern digital life possible, but put humans (and astronauts in orbit) at risk. After weakening to critical levels, the magnetic poles will flip, which is actually less dangerous than it is in the movies. "The decrease in geomagnetic field is much more important and dramatic than the reversal," Dr. Thouveny says. "It is very important to understand if the present field will decay to zero in the next century, because we will have to prepare."

One of the most troubling phenomenon associated with the Earth's weakening magnetic field is the South Atlantic Anomaly, an area over the Atlantic Ocean where the field is about three times weaker than it is at the poles. Satellites passing over the Anomaly have already experienced damage from solar radiation, and it may be a preview of what's to come.