We are also overdue for a Geomagnetic reversal. The field strength can drops 20 times during such periods. "a brief complete reversal 41,000 years ago, which l

We are also overdue for a Geomagnetic reversal. The field strength can drops 20 times during such periods. "a brief complete reversal 41,000 years ago, which led to the magnetic field strength dropping to an estimated 5% of normal during the reversal." https://en.wikipedia.org/wiki/Geomagnetic_reversal https://en.wikipedia.org/wiki/Geomagnetic_reversal