Reuters/Nikola Solic Earth's magnetic poles flipped 42,000 years ago, which may have triggered a global climate crisis, a new study found. The resulting changes in temperatures and radiation levels may have killed off many large mammals. The event may have ultimately contributed to the extinction of Neanderthals. Earth saw a lot of commotion when its magnetic poles flipped 42,000 years ago. Scientists have known about the flip since the late 1960s. Earth's magnetic poles aren't static — they're generated by electric currents from the planet's liquid outer core, which is constantly in motion. As of late, Earth's magnetic North pole has wandered considerably on a path toward northern Russia.