The Earth’s magnetic field is behaving strangely, and no one is quite sure why. It has been known that the Earth’s magnetic pole moves over time since James Clark Ross’ measurements in the Canadian Arctic in 1831, but recently the field has shifted faster than expected — so fast, in fact, that it threatens to mess with navigation systems around the world.
The movement of the Earth’s magnetic field is described by the World Magnetic Model, which is used by navigation systems of all kinds from the GPS on your phone to the complex navigation systems used by ships at sea. The most recent version of the model was released in 2015 and should have been satisfactory until its scheduled update in 2020, however, the magnetic field has moved so quickly that an update is required sooner than that.
During a check of the model in early 2018, researchers at the National Oceanic and Atmospheric Administration (NOAA) and the British Geological Survey in Edinburgh found that the errors were severe enough to be over the threshold for acceptable navigation errors. “The error is increasing all the time,” Arnaud Chulliat, a geomagnetist at NOAA, said in Nature.
Scientists believe that the shifting magnetic field is due to liquid iron within the planet’s core moving around. There was a particularly strong geomagnetic pulse in 2016, where the magnetic field temporarily accelerated under South America. This unexpected development came just after the last update of the model in 2015, so was not accounted for in the model.
In addition, the movement of the magnetic pole has exacerbated the problem, as the error in the magnetic field model is amplified in regions where the field changes quickly like the North Pole. “The fact that the pole is going fast makes this region more prone to large errors,” Chulliat explained.
And now the US government shutdown will prevent the model from being updated on time. The model was scheduled to be updated on January 15 in response to the data collected last year, but this has had to be delayed because of the shutdown. NOAA hopes to release the newest version of the model on January 30, but this is “only a tentative release date” which relies on the shutdown coming to an end, Chulliat told Motherboard.
