Source: What Is That Whistling Sound
What currently has geophysicists like us abuzz is the realisation that the strength of Earth’s magnetic field has been decreasing for the last 160 years at an alarming rate. This collapse is centred in a huge expanse of the Southern Hemisphere, extending from Zimbabwe to Chile, known as the South Atlantic Anomaly. The magnetic field strength is so weak there that it’s a hazard for satellites that orbit above the region — the field no longer protects them from radiation which interferes with satellite electronics.
Earth’s magnetic field is created by convecting iron in our planet’s liquid outer core. From the wealth of observatory and satellite data that document the magnetic field of recent times, we can model what the field would look like if we had a compass immediately above the Earth’s swirling liquid iron core.
These analyses reveal an astounding feature: There’s a patch of reversed polarity beneath southern Africa at the core-mantle boundary where the liquid iron outer core meets the slightly stiffer part of the Earth’s interior. In this area, the polarity of the field is opposite to the average global magnetic field. If we were able to use a compass deep under southern Africa, we would see that in this unusual patch north actually points south.
This patch is the main culprit creating the South Atlantic Anomaly. In numerical simulations, unusual patches similar to the one beneath southern Africa appear immediately prior to geomagnetic reversals.
The impact of a magnetic pole reversal is unknown on a society so dependent on electronic and electromagnetic devises. Air travel is one area it could potentially affect.