Earth’s north magnetic pole has been drifting so fast in recent decades that scientists say that past estimates are no longer accurate enough for precise navigation. On Monday, they released an update of where magnetic north really was, nearly a year ahead of schedule.
The magnetic north pole is moving about 34 miles (55 kilometres) a year. It crossed the international date line in 2017, and is leaving the Canadian Arctic on its way to Siberia.
The constant shift is a problem for compasses in smartphones and some consumer electronics. Planes and ships also rely on magnetic north, usually as backup navigation, said University of Colorado geophysicist Arnaud Chulliat, lead author of the newly issued World Magnetic Model. GPS is not affected because it is satellite-based.
The US military uses magnetic north for navigation and parachute drops and airport runway names are based on their direction in relation to magnetic north. Their names change when the poles are moved. For example, the airport in Fairbanks, Alaska, renamed a runway 1L-19R to 2L-20R in 2009.
The US National Oceanic and Atmospheric Administration and UK tend to update the location of the magnetic north pole every five years, but this update came early because of the pole’s faster movement. The movement of the magnetic north pole “is pretty fast”, Chulliat said.
Since 1831 when it was first measured in the Canadian Arctic it has moved about 1,400 miles (2,300 kilometres) toward Siberia. Since 2000, its speed jumped from about 9mph (15km/h) to 34mph (55km/h).
The reason is turbulence in Earth’s liquid outer core. There is a hot liquid ocean of iron and nickel in the planet’s core where the motion generates an electric field, said University of Maryland geophysicist Daniel Lathrop, who wasn’t part of the team monitoring the magnetic north pole.
“It has changes akin to weather,” Lathrop said. “We might just call it magnetic weather.”
The magnetic south pole is moving far slower than the north.