He explains in great detail the whys of paleomagnetism, the importance of earth's magnetic field, the event itself and more recent history. His diagram speaks to me as I was in the Canadian High Arctic in 1986, when the North Pole was amidst us and we used solar compasses instead.
|Earth’s N magnetic pole|
But most arresting was his diagram from NASA that doubles up on mine from Los Almos is my original posting, adding the situation during magnetic reversal.
|Supercomputer model of Earth’s magnetic field|
The consequences mentioned are not for the faint of heart. I said originally that current extremes in weather may relate to increased Chandler Wobble evidenced by earthquakes found inside continents where they're the least expected. Euan Mearns points to the changed geomagnetism then, which reduces our protection from solar flares and its consequences for satellites and power grids citing the Carrington event 150 yrs ago. I myself follow spaceweather.com and there are many resources for the looking.
I think that convincing Climate Change Deniers is a bit like Constatinople clerics arguing how many angles dance on a pinhead while Turkish invaders were at the gate (Wikipedia)... while today our world is gone wild.