The earths magnetic field is decreasing in strength, and some scientists believe that it is in the midst of a reversal. This is not a new occurrence as it happens about every quarter of a million years, though the last one occured about 750 million years ago. The earths magnetic field protects us from solar radiation by concentrating it towards the largely uninhabited poles.
As you can see, this will not be the case when our field is in the midst of the reversal. What do you think will happen? I predict high incidences of cancer for sure. Also, it seems to me that marine mammals that use the field to navigate will beach themselves left and right. Any thoughts?