Ice Age Magnetic Reversal Was Global Event And Linked With Super Volcano Eruption And Rapid Climate Variability, Says New Research October 17, 2012 in Geology & Climate During the last ice age, around 41,000 years ago, there was a very rapid and complete reversal of the Earth’s geomagnetic field, according to new research. There was already localized evidence of polarity reversals during this time, but with the new research, the theory that it was a global event is now strongly supported. And very interestingly, it is one that nearly coincided with the very fast, short-term climate variability of the last...