An ancient African ritual might be the key to research showing that the Earth's magnetic field is rapidly weakening.
Located from Chile to Zimbabwe is the South Atlantic Anomaly, which researchers believe has an extremely magnetic field. With additional radition flowing into the area, electronics could even be disrupted.
In the Limpopo River Valley, in the southern part of Africa, were a group of Bantu people, who lived about 1,000 years ago. They had a ritual of burning clay huts and grain bins during droughts. The goal was to make the rain return.
"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," geophysicist John Tarduno said.
It turns out that they were onto something they wouldn't even know about at the time.
"We found evidence that these anomalies have happened in the past, and this helps us contextualise the current changes in the magnetic field," Tarduno said.
What Do We Do With This Information?
"We're getting stronger evidence that there's something unusual about the core-mantel boundary under Africa that could be having an important impact on the global magnetic field," Tarduno said.
The weakening means that we are more susceptible to solar winds and cosmic radiation. It could even make the Earth's magnetic pole reverse.
Don't freak out, though, because it's happened before.
The remnants of the African clay burning show that there have been similar weakenings of our magnetic field in the past. These include burnt daga (mud) grain bins, hut floors and cattle enclosures.
The research, published in the Geophysical Review Letters, shows that we are in the midst of a "rapid decay, best expressed by a deepening area of low field called the South Atlantic Anomaly."
"But we know little about the history of the SAA, limiting our ability to place current changes within a long‐term context," the research states. "Here we present a new magnetic record from sites of Southern Africa.
"The new record supports our prior inferences that the SAA is just the most recent manifestation of a recurring phenomenon in the core beneath Africa—called flux expulsion—that is having a profound impact on the expression of the geomagnetic field."
There has been a decay over the past two centuries, according to the research.
With more modeling of different scenarios, the researchers believe they can show how long these episodes of magnetic shifts take. But they are mainly focused on this one region, which could reveal more about the entire planet.