Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more.
CNN
—
If you are using your smartphone to navigate, your system just got a crucial update. Scientists have released a new model tracking the position of the magnetic north pole, revealing that the pole is now closer to Siberia than it was five years ago and is continuing to drift toward Russia.
Unlike the geographic North Pole, which marks a fixed location, the magnetic north pole’s position is determined by Earth’s magnetic field, which is in constant motion. Over the past few decades, magnetic north’s movement has been unprecedented — it dramatically sped up, then in a more recent twist rapidly slowed — though scientists can’t explain the underlying cause behind the magnetic field’s unusual behavior.
Global positioning systems, including those used by planes and ships, find magnetic north using the World Magnetic Model, as it was named in 1990. Developed by the British Geological Survey and the National Oceanic and Atmospheric Administration, this model notes the established position of magnetic north and predicts future drift based on the trajectory of the past few years. To preserve the accuracy of GPS measurements, every five years researchers revise the WMM, resetting the official position of magnetic north and introducing new predictions for the next five years of drifting.
“The more you wait to update the model, the larger the error becomes,” said Dr. Arnaud Chulliat, a senior research scientist at the University of Colorado, Boulder, and the NOAA National Centers for Environmental Information. “The way the model is built, our forecast is mostly an extrapolation given our current knowledge of the Earth’s magnetic field.”
The scientists released two models on December 17: the standard WMM, with a spatial resolution of approximately 2,051 miles (3,300 kilometers) at the equator, and the first high-resolution model, with spatial resolution of about 186 miles (300 kilometers) at the equator. While anyone can use the more powerful high-resolution model, most GPS hardware used by the general public incorporates the standard WMM and isn’t equipped to handle the other — and many users won’t benefit from the upgrade, said Dr. William Brown, a geophysicist and geomagnetism researcher with the British Geological Survey, in an email.
“Major airlines will upgrade the navigation software across their entire fleets of aircraft to load in the new model, and militaries in NATO will need to upgrade software in a huge number of complex navigation systems across all kinds of equipment,” Brown told CNN. But for most people, the switch isn’t necessary.
“Think of it like upgrading your smartphone — you don’t necessarily want to buy a new phone just to upgrade an app to a new version that is more powerful,” he said.
Changing to the new model should be a seamless transition for GPS users; with the update, scientists verified the accuracy of the previous model’s predictions about where magnetic north would end up by 2025, Chulliat said.
“The forecast was very good,” he said. “And so the new model confirmed that we were not very far off.”
But why are all these updates necessary, and why doesn’t magnetic north stay in one place?
At the top of the world in the middle of the Arctic Ocean lies the geographic North Pole, the point where all the lines of longitude that curve around Earth from top to bottom converge in the north.
Marking the North Pole is challenging, as it’s covered by moving sea ice, but its geographic location, also known as the true North Pole, is fixed.
By comparison, the magnetic north pole is the northernmost convergence point in Earth’s magnetic field, also known as the magnetosphere. Generated by the churning molten metals in Earth’s core, the magnetosphere shields the planet from harmful solar radiation and keeps solar winds from stripping away Earth’s atmosphere.
Because the convective sloshing at Earth’s core never stops, the magnetosphere is never static. As a result, its northernmost point is always on the move.
British explorer Sir James Clark Ross discovered the magnetic north pole in 1831 in northern Canada, approximately 1,000 miles (1,609 kilometers) south of the true North Pole. We now know that every day, magnetic north traces an elliptical path of about 75 miles (120 kilometers).
Since its discovery, magnetic north has drifted away from Canada and toward Russia. By the 1940s, magnetic north had moved northwest from its 1831 position by about 250 miles (400 kilometers). In 1948, it reached Prince Wales Island, and by 2000 it had departed Canadian shores.
“It has typically moved about 10 km (6.2 miles) per year or less over the last 400 years,” Brown said.
However, the latest WMM update follows a period of highly unusual activity for the magnetic north pole. In 1990, its northern drift accelerated, increasing from 9.3 miles (15 kilometers) per year to 34.2 miles (55 kilometers) per year, Chulliat said. The shift “was unprecedented as far as the records we have,” he added.
Around 2015, the drift slowed to about 21.7 miles (35 kilometers) per year. The rapid deceleration was also unprecedented, Chulliat said. By 2019, the fluctuations had deviated so far from the prior model that scientists updated the WMM a year early.
Scientists expect that the drift toward Russia will continue to slow, though there is some uncertainty about how long the slowdown will persist and if it will continue at its current pace, according to Brown.
“It could change (its) rate, or even speed up again,” Brown said. “We will continue to monitor the field and to assess the performance of the WMM, but we do not anticipate needing to release a new model before the planned update in 2030.”
Earth’s magnetic field has behaved even more dramatically in the past, with the magnetosphere weakening so much that its polarity reversed. This flips the magnetic north and south poles, and the change can last for tens of thousands of years. Scientists have estimated that this polar flip, which can take thousands of years to complete, happens about once every million years, though the time between flips has varied greatly — from 5,000 years to as much as 50 million years. The signs that precede such flips are also not well understood, making them difficult to predict, Brown said. The last big flip was about 750,000 to 780,000 years ago.
During a polar flip, animals that migrate using the magnetic field to find their way, such as whales, butterflies, sea turtles and many species of migratory birds, could be affected. A flip would disrupt radio communication and scramble navigation systems. Orbiting satellites would be at risk, as a weakened magnetic field would offer less protection against space weather.
While life on Earth has weathered multiple magnetic reversals over more than 100 million years, “we’ve never experienced a reversal when modern technology was present,” Brown said.
“It would certainly be an interesting time for engineers to adapt our technology to, but hopefully one they’d have a slow, centuries-long build up to, rather than any sudden change.”
Mindy Weisberger is a science writer and media producer whose work has appeared in Live Science, Scientific American and How It Works magazine.