Magnetic model for navigation is modified by shifting pole

British and American research bodies have given the World Magnetic Model an interim adjustment. The reason is that the magnetic poles are moving faster than expected, with risks to navigation services, among other things.

The US NOAA and the British Geological Survey have released World Magnetic Model v2. This model describes the Earth’s magnetic field and is used as a reference for direction and thus for navigation. NATO and defense ministries, among others, rely on the WMM. In addition, magnetometers from smartphones, ships and aircraft, for example, use the WMM as a reference to correct measurements from magnetic north to true north.

Because the position of the Earth’s magnetic field fluctuates, it is agreed that the World Magnetic Model will be updated every five years. The current model dates from 2015 and should therefore be overhauled in 2020. A year ago, however, the NOAA reported that the existing model for the Arctic region was no longer accurate.

The speed at which the magnetic north pole moves increases. In the 1990s, it had already increased from 15 kilometers per year to 55 kilometers per year, Nature wrote. Around 1900, the magnetic pole was still near the land in northern Canada, but now it is accelerating towards Siberia and is a point close to the geographic north pole in the Arctic Ocean.

Last September, the NOAA and the BGS already released a preliminary version of WMMv2 and the official version was planned to be published on January 15th. However, the US government shutdown in January threw a spanner in the works, and the date was moved to the end of January. After another postponement, the model was released on February 4.

According to researchers, the reason for the accelerated displacement of the magnetic north pole is probably due to currents in the liquid outer core of the earth, which consists largely of nickel and iron. The magnetic field near Canada would be weakened due to strong currents there, causing a field near Siberia to pull the pole towards itself.

Locations of the geomagnetic and magnetic poles. Source: World Data Center for Geomagnetism

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