People keep trying to come up with reasons that we should worry about the magnetic field collapsing or reversing, but honestly I think it's fine. Whatever minor problems it causes will be made up for by the mid-latitude auroras.
Over the last couple of months, Earth's magnetic fields have been shifting rapidly. Although the magnetic fields do move regularly, the current shift has been unexpected and unprecedented. As many location systems are reliant on the magnetic fields to function, the accuracy of such tools is being shifted beyond the maximum acceptable error. The scientists are therefore updating these tools in order to prevent ships from running aground, similarly to 2029: Disaster Movie.
Locational and navigational systems use the magnetic field, combined with a model of field behavior, to do fancy math and pop out data. Because of the rapid shifts, a new model was scheduled to be created; however, the model has been considerably delayed by the US government shutdown.
As shifts occur, the error of geopositional data will increase until a new model is released. The effect is especially pronounced as you move toward the poles.
Cueball is saying that because of the currently published magnetic declination data being slightly incorrect, his schooners (old merchant sailing ships) may go off-course and crash on shoals. This is to illustrate how magnetic pole shift doesn't actually affect many people's daily lives. Modern ships' navigation systems do not rely on magnetic pole location – in contrast to old vessels which mostly used a compass. However, airplanes do use compasses readings in determining runway numbers. Thus, northern countries have started to use the Geographic North Pole to determine runway numbers, which could otherwise need recalibration on occasion, as would all the not-necessarily magnetic flightdeck compasses.
Since the movement is only about two-fifths of a degree, it wouldn't cause much disruption for Cueball or require him to adjust anything about his lifestyle, but since the speed of the change has been steadily increasing over the past few years, it may mean we are heading for a geomagnetic reversal in the next few decades, something very exciting indeed. During a magnetic reversal, the poles wouldn't just switch places; several different poles would form and interact chaotically, and it's likely that one of them would end up close enough to where Randall lives to cause auroras to become more common at some point during the transition.
In the title text, Randall mentions that there are reasons people could be concerned, but says that they would be more than made up for by newly being able to experience mid-latitude auroras. Since auroras occur between 10° and 20° from the magnetic poles, the migration of the poles to middle latitudes would cause the auroras to occur there as well; since more people live at middle latitudes than in the Arctic and Antarctic Circles, and since auroras are considered aesthetically attractive,[citation needed] the psychological benefits of the drifting poles might more than make up for the technical difficulties it causes.