Poles Are Shifting, Earth's Protective Magnetic Shield Could Be Disrupted

The Poles Are Shifting, the Magnetic Field Is Flipping and This Will Get Really Nasty

Strange Sounds

The shield that protects the Earth from solar radiation is under attack from within.

We can’t prevent it, but we ought to prepare.

One day in 1905, the French geophysicist Bernard Brunhes brought back to his lab some rocks he’d unearthed from a freshly cut road near the village of Pont Farin.

When he analyzed their magnetic properties, he was astonished at what they showed: Millions of years ago, the Earth’s magnetic poles had been on the opposite sides of the planet. North was south and south was north. The discovery spoke of planetary anarchy. Scientists had no way to explain it.

Today, we know that the poles have changed places hundreds of times, most recently 780,000 years ago.

Sometimes, the poles try to reverse positions but then snap back into place, in what is called an excursion. The last time was about 40,000 years ago.

We also know that when they flip next time, the consequences for the electrical and electronic infrastructure that runs modern civilization will be dire. The question is when that will happen.

In the past few decades, geophysicists have tried to answer that question through satellite imagery and math. They have figured out how to peer deep inside the Earth, to the edge of the molten, metallic core where the magnetic field is continually being generated. It turns out that the dipole — the orderly two-pole magnetic field our compasses respond to — is under attack from within.

The north magnetic pole is on the run, a sign of enhanced turbulence and unpredictability. A cabal in the Southern Hemisphere has already gained the upper hand over about a fifth of the Earth’s surface. A revolution is shaping up.

If these magnetic blocs gain enough strength and weaken the dipole even more, they will force the north and south poles to switch places as they strive to regain supremacy.

Scientists can’t say for sure that is happening now — the dipole could beat back the interlopers. But they can say that the phenomenon is intensifying and that they can’t rule out the possibility that a reversal is beginning.

The Earth’s magnetic field protects our planet from dangerous solar and cosmic rays, like a giant shield. As the poles switch places (or try to), that shield is weakened; scientists estimate that it could waste away to as little as a tenth of its usual force.

That radiation isn’t hitting the surface yet. But at some point, when the magnetic field has dwindled enough, it could be a different story. Daniel Baker, director of the Laboratory for Atmospheric and Space Physics at the University of Colorado, Boulder, one of the world’s experts on how cosmic radiation affects the Earth, fears that parts of the planet will become uninhabitable during a reversal.

The dangers: devastating streams of particles from the sun, galactic cosmic rays, and enhanced ultraviolet B rays from a radiation-damaged ozone layer, to name just a few of the invisible forces that could harm or kill living creatures.