A weak magnetic field would increase the cancer rates as dangerous radiation would more easily get through the weak ionosphere.
There is nothing much anyone could do about this, so it remains wait and see. Time scales are more likely to be thousands of years than decades.
There is a big difference between “disaster” to a geophysicist and a biologist or technologist. While obviously the world has not geologically ended on any of these previous magnetic pole reversals, increases in biological effects like cancer would probably not appear obvious in the fossil record.
The more concerning thing is that if the rate of pole movement has really increased this much in the past century, then a shift could really be imminent. 600 miles seems huge to me for a single century.
Not only might cancer and other health effects be a factor, but our technology could be severely affected. Obviously there is no fossil record of the effects on technology, unless there really have been prior advanced civilizations on Earth. Maybe the Atlanteans couldn’t figure out how to keep their electrical grid working.
Solar flares produce the same effect as a nuclear explosion’s EMP and destroy electrical circuitry. If we enter a period of centuries where solar flares strong enough to do that are common, we will need to shield our electrical grid and devices. Or move to local power generation rather than a grid, and fiber optics or laser based telecom rather than copper land lines and wireless for telecom.
Lead lined baseball caps worn backwards. Hussein is in the vanguard on this.