The magnetic north pole—the one that we rely on to calibrate compasses and complex navigation systems—has always been a little squirrely. Driven by the unpredictable swirls and flows in the Earth’s iron core, the magnetic pole had been drifting around northern Canada for hundreds of years. But in the last 150 years or so, the magnetic pole began darting toward Siberia.
Because of that, NOAA and British Geological Survey—which update the World Magnetic Model (WMM) every five years to aid in navigation—for the first time ever issued an emergency update to the model on Monday, reports Alexandra Witze at Nature News & Comment.
Scientists first learned about the unpredictable movements of the Earth’s magnetic north pole 400 years ago, when English mathematician Henry Gellibrand calculated that it had moved hundreds of miles closer to the geographic north pole over the course of 50 years, reports Shannon Hall at The New York Times. For centuries, it wandered around northern Canada’s Arctic Archipelago. But in 1860, it began making a straight-line journey across the Arctic Ocean and toward Siberia, traveling about 1,500 miles and crossing the international date line in 2017.
While for most of the 20th century it moved about six miles per year, in the 1980s it began speeding up, reaching about 35 miles per year by 2000. In 2015, when the last WMM was released, it had slowed to 30 miles per year, and the WMM release that year was based on the presumption that it would continue slowing. But since then, the pole has picked up the pace again, putting the WMM so out of whack that an update was warranted.
Last year, officials realized that the model would become so inaccurate, it could cause problems with military and ocean navigation and even impact air traffic control. Maya Wei-Haas at National Geographic notes that people using civilian navigation probably have not have noticed any problems. But those traveling north of 55 degrees latitude, including airliners, would have. The premature update incorporates the last three years of data and should improve things until the official five-year year WMM update is released at the end of 2019.
So what’s going on with the pole, and should we be worried? Witze reports for Nature that this is one global problem that humans aren’t responsible for. The magnetic field is generated by molten iron and nickel surrounding the Earth’s solid, iron core. As that liquid metal swirls and spins, it generates electric currents and the magnetic field that surrounds the planet. But that churning core is unpredictable, changing the spot where the magnetic field lines return into the Earth, aka magnetic north, a moving target. Researchers hypothesize that the recent wandering of the pole might be linked to a high-speed jet of liquid iron, which they believe is currently active deep under Canada, that is weakening the magnetic field in that area. Another strong patch of magnetic field in Siberia may be stepping in and tugging the pole eastward.
“The location of the north magnetic pole appears to be governed by two large-scale patches of magnetic field, one beneath Canada and one beneath Siberia,” Phil Livermore, a geomagnetist at the University of Leeds said at the American Geophysical Union Annual Meeting reports Witze. “The Siberian patch is winning the competition.”
As long as researchers can keep track of the peripatetic magnetic pole, however, there’s nothing to worry about. “It’s not the fact that the pole is moving that is a problem, it’s the fact that it’s accelerating at this rate,” William Brown, geophysicist at the British Geological Survey tells Hall at The New York Times. “The more acceleration or deceleration there is, the harder to predict where the thing is going to be.”
Eventually, Earth’s magnetic north and south pole will wander extremely far afield—throughout time the planet’s poles have periodically flipped, and we are geologically due for it to happen again, and Hall reports that some researchers believe our wandering pole may be a precursor to this, though others disagree. But don't worry. The flip will likely take thousands of years, giving humanity ample time to prepare for the day when our compasses start pointing the wrong direction.