North, I was once surprised to learn, is not always north. There’s geographic north, “up” on maps toward the North Pole, and then there’s magnetic north, which is where compass needles point. Right now the two kind of line up, but that isn’t always the case. Earth’s magnetic field — which guides compasses, animals and auroras — likes to wander, and it’s reversed entirely in the past: Magnetic north was in the geographic south.
Some geologists had thought the flips could be fairly quick, possibly even taking place within a single human lifetime. That’s a big deal, since current fluctuations suggest magnetic north might be gearing up for such a major shift soon. And while it may be a smooth ride, we honestly don’t know enough about how Earth reacts to these things to know if we should worry or not. And whatever natural problems arise would pale in comparison ...
