Geomagnetic South Atlantic Anomaly and global sea level rise: A direct connection?

We highlight the existence of an intriguing and to date unreported relationship between the surface area of the South Atlantic Anomaly (SAA) of the geomagnetic field and the current trend in global sea level rise. These two geophysical variables have been growing coherently during the last three centuries, thus strongly suggesting a causal relationship supported by some statistical tests. The monotonic increase of the SAA surface area since 1600 may have been associated with an increased inflow of radiation energy through the inner Van Allen belt with a consequent warming of the Earth's atmosphere and finally global sea level rise. An alternative suggestive and original explanation is also offered, in which pressure changes at the core–mantle boundary cause surface deformations and relative sea level variations. Although we cannot establish a clear connection between SAA dynamics and global warming, the strong correlation between the former and global sea level supports the idea that global warming may be at least partly controlled by deep Earth processes triggering geomagnetic phenomena, such as the South Atlantic Anomaly, on a century time scale.

► We compare South Atlantic Anomaly (SAA) surface and sea level in the last 300 years. ► SAA and sea level show a strong correlation supported by statistical tests. ► Increasing the SAA surface may have increased the inflow of radiation energy. ► The radiation energy may have warmed the atmosphere causing the sea level change. ► Alternatively magnetic field and sea level changes may have a common internal cause.