Earth’s north magnetic pole is on move again

Check your compass again – Earth’s north magnetic pole is moving toward Siberia.

Since at least the early 19th century, Earth’s north magnetic pole has been situated in the Canadian Arctic and slowly moving north and east. But now, after a recent acceleration, it is closer to Siberia than to Canada, according to analyses by international groups of scientists.

The shift will prompt airplane operators, mariners, drilling companies and global trade industries to update their navigation systems. Updates will also improve the accuracy of technology from GPS-enabled phones to nuclear submarines.

“The current behaviour of magnetic north is something that we have never observed before,” William Brown, a global geomagnetic field modeler at the British Geological Survey, said in a statement.

Why magnetic north is moving

The magnetic north pole is different from the geographic North Pole. The geographic North Pole (or “true north”) is where Earth’s axis meets its surface and is a fixed point on the globe. The magnetic north pole, where compass needles point, is about 1,200 miles south and is where geomagnetic field lines are vertical.

Earth’s magnetic north is not static. Like an anchorless buoy pushed by ocean waves, the magnetic field is constantly on the move as liquid iron sloshes around in the planet’s outer core. The movement of the molten, electrically conductive iron gives rise to our planet’s magnetic field.

“The (core’s) fluid itself flows as easily as water does on the surface,” said Ciaran Beggan, a geophysicist at the British Geological Survey. “It both generates the magnetic field and drags it with it as well.”

The location of the magnetic north pole was first discovered in 1831 by Arctic explorer James Clark Ross. On an expedition, he mapped and explored Boothia Peninsula in Nunavut, in the Canadian Arctic. There he found the spot where his compass dipped almost vertically – indicating the magnetic north pole, also known as the magnetic dip pole. The magnetic pole was last visited in person in 2007 by a Canadian team of researchers.

Every five years, scientists at the British Geological Survey, the U.S. National Oceanic and Atmospheric Administration and other agencies release an updated World Magnetic Model of Earth’s magnetic field, along with forecasts for the north pole into the short-term future. NOAA said the model is the standard one used for aircraft satellite navigation, attitude, and heading referencing systems that use the geomagnetic field.

Scientists from 19 international institutions release a complementary magnetic model called the International Geomagnetic Reference Field (IGRF), which is also updated every five years. The model is intended for scientific research but can also be used like the World Magnetic Model, said Beggan, who coordinated the release of the IGRF.

The models take in observations from satellites that continuously measure Earth’s magnetic field, as well as from ground observatories worldwide. Using the models, Beggan said, scientists can determine where the magnetic north pole has moved.

Since the 1830s, the magnetic pole has traveled about 1,500 miles north and eastward in the Northern Hemisphere. In the 2000s, the movement accelerated to as fast as 50 kilometers per year. In the past five years, it decelerated to 35 kilometers per year.

No one knows why, but Beggan said it’s probably linked to some pockets of the magnetic field getting stronger and others weakening.

He said the overall strength of the Earth’s magnetic field has been decreasing over the past couple hundred years, but it doesn’t decrease uniformly.

For instance, the field is getting weaker in Canada but stronger around Siberia.

“That pulls the magnetic pole towards Siberia,” Beggan said. “The underlying physical reason for that? We’re not quite sure. It might have to do with the way the fluid-flow under the north pole is changing.”

Why it’s important to know pole’s location

Most people probably won’t notice major differences on their compasses. Changes are one-tenth to one-quarter of a degree per year in most places around the world, and our compasses are accurate to only about a degree.

But many industries rely on highly accurate magnetic field maps for navigation. Companies update navigation systems in satellites, aircraft and smartphone apps that may operate in areas where GPS doesn’t work as well – such as northerly routes or geographic poles.

The location of the magnetic pole is also important in underground operations such as excavations, archaeology measurements, or exploration for oil and gas. To drill underground, industries rely on magnetometers that use the magnetic field to give directions.

“Although it seems a bit arcane, it has lots of practical applications,” Beggan said. “You do need to kind of make sure that the maps are accurate in order to ensure that error doesn’t accumulate over time.”

Since the 1600s, when reliable calculations for magnetic north began, it has not been found over Siberia – although Beggan said it probably reached Siberia at some point in Earth’s history. At its current trajectory, it is likely to approach Siberia in the next decade.

Alternatively, the motion could abruptly stop and reverse to Canada, he said. That’s just part of the uncertainty when you’re making predictions based on activity 3,000 miles away in Earth’s core.

While the magnetic north pole is on the move, the south magnetic pole is comparatively static. It’s moving northward, but at only about five to 10 kilometers per year, with hardly any movement in the past few hundred years.

While both poles are pulled by the movement in the core, the influence is not symmetric. The magnetic field is moving and flowing differently in the Northern Hemisphere than the Southern Hemisphere “for reasons we’re not sure,” Beggan said.

Then there’s the odd trend of the magnetic field overall, which has weakened about 9 percent on average over the past 200 years. Some speculate that this could presage a flip of the north and south magnetic poles, but scientists say there’s no evidence that any pole reversal is imminent – plus, it would take place over hundreds to thousands of years.

So we’re safe, for now.