Magnetic reversal 42,000 years ago triggered climate change 

Aussie researchers have analysed the radiocarbon record from ancient trees in New Zealand that were alive when the magnetic poles flipped. https://www.dailymail.co.uk/sciencetech/article-9277659/Magnetic-reversal-42-000-years-ago-triggered-climate-change.html?ns_mchannel=rss&ns_campaign=1490&ito=1490