The Earth's magnetic field is changing at full speed.

Something strange is happening above the planet: the north magnetic pole is moving so fast that world experts in geomagnetism will be forced to update the magnetic declination model, ahead of schedule. The magnetic declination model must be applied to course calculations on nautical charts to facilitate navigation, not only on ships but also in modern mapping systems such as Google Maps. But let’s not get ahead of ourselves, we break it down.

We already know that magnetic poles are not fully aligned with the geographic poles of Earth and the position of these poles changes slightly with the passage of time. Mainly, this is because of the movements of the liquid materials that make up Earth’s nucleus (molten iron and nickel) which are the originators of our planet’s magnetic field. Currently, the magnetic north pole moves from Canada to Russia at a rate of several tens of kilometers per year.

Due to this movement of the magnetic north pole, it has become precedent for the US National Oceanic and Atmospheric Administration (NOAA) and the British Geological Survey (Edinburgh) to meet every five years to update the World Magnetic Model. 

©  World Data Center for Geomagnetism/Kyoto Univ.

The most recent version of this model was published in 2015, which is meant to be valid for 5 years until the next version is released in 2020. The problem is that the magnetic field is changing so fast that researchers often have to make corrections ahead of time. The last model had a very unfortunate history, soon after it was released in 2016, part of the magnetic field temporarily accelerated in the depths of northern South America and the eastern Pacific Ocean, This change was tracked by satellites such as the European Space Agency’s Swarm mission. 

In early 2018, the alarm went off during their annual verifications when experts realised that the current model was so inaccurate that it exceeded the acceptable limit of navigational errors. Despite this, the appointment to update the magnetic declination model had to be postponed due to the partial closure of the U.S government.


This article was adapted from a version published by Alexandra Witze in Nature 565, 143-144 (2019)

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