A minority opinion, held by such figures as Richard A. Muller, is that geomagnetic excursions are not spontaneous processes but rather triggered by external events which directly disrupt the flow in the Earth's core.
Supporters of this theory hold that any of these events lead to a large scale disruption of the dynamo, effectively turning off the geomagnetic field for a period of time necessary for it to recover.
[citation needed] Richard A. Muller and Donald E. Morris suggest some geomagnetic reversals may be caused by very large impact events and following rapid climate change.
If the sea-level change is sufficiently large (>10 meters) and rapid (within a few hundred years), the velocity shear in the liquid core disrupts the convective cells that drive the Earth's dynamo.
Due to the weakening of the magnetic field, particularly during the transition period, more radiation would reach the Earth's surface, increasing production of beryllium 10 and levels of carbon 14.
The major hazard to modern society is likely to be similar to that of geomagnetic storms, where satellites and power supplies may be damaged, and compass navigation would also be affected.
[8] Recent analysis of the geomagnetic reversal frequency, oxygen isotope record, and tectonic plate subduction rate, which are indicators of the changes in the heat flux at the core mantle boundary, climate and plate tectonic activity, shows that all these changes indicate similar rhythms on million years' timescale in the Cenozoic Era occurring with the common fundamental periodicity of ~13 Myr during most of the time.