What the **** do the magnetic poles have to do with UV radiation. The earth isn't surrounded by a magnetic field, it's surrounded by something called the ozone field (WHICH BLOCKS UV RADIATION), and the earth itself is the magnet.
Actually the earth is surrounded by a magnetic field. Which also helps deflect and break down Electromagnetic Radiation. Hence we get pretty things like the northern/southern lights. Which is radiation hitting the magnetic field around the earth.
If there was a polar shift, it could take the form of a physical one or a purely magnetic one.
If the shift was physical the entire molten core will slide around underneath the crust causing massive fissures/earthquakes/volcanoes etc. Then with the hole changing of the poles, would stop all electrical production as the field is reversed.