News of the approaching magnetic pole reversal might have been greatly exaggerated. At least this is the opinion of an international team of researchers, who compared the current state of our planet’s magnetic field to similar occurrences in the recent geological past, where the field weakened and then recovered.
The idea that the poles might be getting ready to reverse has several substantial pieces of evidence. In the last 200 years Earth’s magnetic field has become weaker, and a weak zone – the South Atlantic Anomaly, which stretches from Chile to Zimbabwe – has become larger. The team looked at two important geomagnetic events, one dating back to about 41,000 years ago and the other 34,000 years ago.
Both events are not pole reversals but geomagnetic excursions, where the field come close to reversing but then goes back to its original structure. Studying the data from these two events, the researchers found no evidence that what is going on on Earth right now is an early stage of either geomagnetic reversal or excursion. The study is published in the Proceedings of the National Academy of Science.
The team also compared current analysis with rocks from a slightly earlier period, centered at 49,000 and at 46,000 years ago. The magnetic field from those times is quite similar to what it is like today and the team even found something akin to the South Atlantic Anomaly in both time periods. Neither periods experienced a reversal.
“There has been speculation that we are about to experience a magnetic polar reversal or excursion. However, by studying the two most recent excursion events, we show that neither bear resemblance to current changes in the geomagnetic field and therefore it is probably unlikely that such an event is about to happen,” co-author Professor Richard Holme, from the University of Liverpool, said in a statement.
“Our research suggests instead that the current weakened field will recover without such an extreme event, and therefore is unlikely to reverse.”
Geomagnetic reversal doesn’t occur at regular intervals. They occur between 100,000 and 1 million years and the magnetic field takes between 1,000 and 10,000 years to flip, although it might be faster. The last time a complete reversal happened was 780,000 years ago and scientists think it might have been unusually fast, it could even have happened within a human lifetime.