The Earth’s magnetic field is a powerful force—surrounding our planet and protecting life from harmful solar radiation by deflecting charged particles away. But this field is continuously changing and our history holds evidence of at least several hundred global magnetic reversals, where north and south magnetic poles trade places. So what, exactly, will happen to life on Earth of the swap happens again? According to The Conversation, the magnetic field won’t be zero during the reversal but will take a more complex, weaker form. In fact, it could fall to 10 percent of its present-day strength and create magnetic poles at the equator. This alteration will also weaken the field’s shielding effect, allowing heightened levels of radiation on the Earth’s surface. Today, this would increase the risk for satellites, aviation, and ground-based electrical infrastructure. We would also experience the equivalent of geomagnetic storms, like the one that took place in 2003.
More than a dozen years ago, this Halloween storm caused local electricity grid blackouts in Sweden, forced the rerouting of flights to avoid communication blackout and radiation risk, and interfered with satellites. Caused by the interaction of large eruptions of solar energy and our magnetic field, the impact of a major storm on today’s electronic infrastructure is still unknown. We can assume, however, that significant time without electricity, GPS or the internet would have a major impact. Economically, alone, is could cost us tens of billions of dollars a day.
We cannot definitively predict what would happen to our species during this time, though past reversals have been linked to mass extinctions. Many animal species have some form of magneto-reception that enables them to sense the Earth’s magnetic field for long-distance navigation during migration.
So when will this next ‘flip’ occur?
According to The Conversation, geomagnetic reversals occur a few times every million years, on average—though the interval between reversals is irregular. Complicating the issue are temporary and incomplete reversals, in which the magnetic poles move away from the geographic poles before returning back to their original locations. The last full reversal, Brunhes-Matuyama, occurred 780,000 years ago; the last temporary reversal, the Laschamp event, occurred 41,000 years ago and lasted less than 1,000 years.
Essentially, we are “overdue” for a full reversal. That, combined with the fact that the Earth’s field is decreasing at a rate of 5 percent per century, has led to suggestions that the field could reverse within the next 2,000 years.
Theoretically, the Earth’s magnetic field is generated within the core of our planet—a movement like the atmosphere, governed by the laws of physics—that we should be able to track. The difficulties of predicting the behavior of our earth’s “inner atmosphere” are great—just think of how often we incorrectly predict the weather. Still, a global network of ground-based observatories and satellites are actively measuring how the magnetic field is changing, giving us insight into how the core is moving.
What do you think? Could we survive a magnetic field flip?