New research shows the most significant weakening is happening under Africa which has been dubbed the ‘South Atlantic Anomaly’ (SAA).
As well as giving us our north and south poles, the magnetic field blankets the Earth, protecting it from solar winds and cosmic radiation.
The forcefield has weakened significantly over the past 160 years and scientists now suggest it could be in the process of flipping.
Such a change would be a switch in magnetic polarity and would see compasses point south rather than north.
Scientists believe such an occurrence has actually happened several times in the history of our planet, transpiring roughly every 200,000 to 300,000 years.
Approximately 40,000 years ago, the field is said to have attempted to switch before snapping back into place.
The SAA, which stretches all the way from Zimbabwe to Chile, is now of particular interest to scientists because it has weakened dramatically over the last 160 years.
The field is now so weak that it is expected be hazardous for satellites to enter the region.
It’s thought the SAA’ might be an omen of an impending pole reversal but very little hard data on reversals currently exists.
A new study from the University of Rochester, published in Geophysical Research Letters, has attempted to delve deeper into the worrying phenomenon.
The researchers gathered data from sites in southern Africa and compiled a record of Earth’s magnetic field strength over many centuries.
They used ancient African clay remnants dating back to the early and late Iron Ages to study past magnetic fields using “archaeomagnetism.”
One of the lead researchers, John Tarduno, explained: “When you burn clay at very high temperatures, you actually stabilise the magnetic minerals, and when they cool from these very high temperatures, they lock in a record of the earth’s magnetic field.”
They discovered that the magnetic field in the region has fluctuated several times, leading them to believe that the SAA is the most recent display of a recurring phenomenon in Earth’s core.
Mr Tarduno said: “We’re getting stronger evidence that there’s something unusual about the core-mantle boundary under Africa that could be having an important impact on the global magnetic field.”
Lead author Vincent Hare added that their data does not necessarily predict a complete pole reversal: “We now know this unusual behaviour has occurred at least a couple of times before the past 160 years, and is part of a bigger long-term pattern.
“However, it’s simply too early to say for certain whether this behaviour will lead to a full pole reversal.”
In an article for The Conversation, University of Leeds geophysicists Phil Livermore and Jon Mound wrote: “Were pole reversal to happen today, the increase in charged particles reaching the Earth would result in increased risks for satellites, aviation and ground-based electrical infrastructure.”
Live Science previously reported that charged solar particles could punch holes in Earth’s atmosphere akin to the ozone hole above Antarctica.