The biggest issue during pole reversal will be increased exposure to solar radiation. With the magnetic poles currently near the North / South geographic poles, the magnetic field directs solar radiation towards N/S geographic poles. This is what 'feeds' the Aurora's. This is also what protects our equatorial and mid-latitudes from solar radiation. During a reversal the magnetic field strength will weaken and the direction will become variable (hence the increasing fluctuation of magnetic variation). This means that our equatorial and mid-latitude regions (where most of us live) will be more exposed to solar radiation. The significance of this is unknown and subject to debate.