WASHINGTON • The position of the earth's magnetic north pole is moving far faster than it has, sending scientists scrambling to put out a new model this week.
The magnetic north is the point at which the planet's magnetic field points vertically down.
The World Magnetic Model is critical to sea and military navigation as well as smartphones. It normally is updated every five years but the schedule has been pushed forward one year "due to unplanned variations in the Arctic region", the US National Centres for Environmental Information said.
The earth's magnetic field is generated mainly by movement of the liquid iron that makes up most of the earth's core, 3,000km below the surface. That movement is what makes the magnetic poles shift, but the cause of the recent acceleration remains a mystery.
Scientists at the US National Oceanic and Atmospheric Administration and British Geological Survey have had to update their model ahead of the late 2019 scheduled deadline.
"It's a very slow movement, but it's very real, and over several decades, it can be several degrees," said geophysicist Arnaud Chulliat. It does not matter much in the most populated areas, but "near the magnetic pole, the change is faster".
The model makes it possible to correct the direction indicated by the compass to find the geographic north, which is fixed.
Since the end of the 19th century the magnetic north has been heading towards Siberia. Since the 1990s, the movement has accelerated across the Arctic Ocean, from about 15km a year to 50-55km a year currently.