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The Role of Geomagnetic Field Intensity in Late Quaternary Evolution of Humans and Large Mammals. Kinda dry and upper division, but to make a long story short, climate changed and changed life with it when the magnetic field was found to be swapping poles due to cosmic rays thru ozone holes and cloud cover induced ice ages apparently. "episodes of Late Quaternary extinction of mammalian megafauna occurred close to the Laschamp and Blake magnetic excursions..."

https://agupubs.onlinelibrary.wiley.com ... 18RG000629

An observation of the prior observations. The whole series is a must see if you want motivation to enjoy life more now. Eyes open, no fear.

Then Cosmic Rays effects happen.

This ones To Do List starts at 58:35