The Shifting Geographic North Pole: How Climate Change is Redefining Our Planet

The axis of rotation of the earth is not immutable. It naturally oscillates under the effect of internal and external forces, such as the movements of the terrestrial nucleus or climatic variations. But a study published in Geophysical Research Letters by researchers from ETH Zurich and the University of Vienna reveals an unprecedented phenomenon: human activities now modify the position of the Geographic North Pole in a measurable way.

A planet that vacillates

The rotation of the earth around its axis is not rigid. What is called “polar movement” designates the displacement of the axis of terrestrial rotation compared to the surface of the globe. This phenomenon, well documented for more than a century, is influenced by multiple natural factors: convection in the liquid external nucleus, the interactions between the nucleus and the mantle, the ocean and atmospheric tides, or even the pressure exerted by water and ice on the earth's surface. These mechanisms cause a slow and regular tilting of the axis, perceptible on time ladders ranging from a few days to several decades.

But since the beginning of the 20th century, the distribution of terrestrial masses has been increasingly disturbed by human activity. In their study, Mostafa Kiani Shahvandi and Benedikt Soja show that the effects of climate change – and more specifically the so -called barystatic processes, linked to mass redistribution between continents and oceans – now play a major role.

Their projections indicate a displacement of the geographic North Pole up to 27.4 meters by 2100 in the RCP8.5 scenario (high emissions). Even in the more favorable RCP2.6 scenario, this slide reaches 12 meters. The current climate therefore prints a very real signature on the rotation mechanics of our planet.

Fonte des Glaces: a planetary pendulum

The melting of the glacial masses thus literally redraws the balance of the planet. The main factor of the current drift of the North Pole is the accelerated melting of the Greenland ice cap. Located in the northern hemisphere, its mass, when it turns into water and joins the oceans, strongly modifies the distribution of loads on the earth's surface. This redistribution leads to a change in the axis of rotation to the west. The researchers specify that this influence induces an almost symmetrical signature in the components of the polar movement, causing a displacement oriented around 45 ° west longitude.

Antarctica, although less influential than Greenland because of its opposite location, plays a complementary, but more variable role. Under a high emission scenario (RCP8.5), the increased melting of the Amundsen Sea sector – a particularly vulnerable region – induces a drift is towards longitudes less than 30 ° west. This component becomes dominant in polar dynamics as emissions increase, modifying the trajectory of the terrestrial axis.

For their sides, mountain glaciers, although less scope, also exert a significant pressure when they melt. Their contribution manifests itself by a drift of the pole to the east. Added to this is the influence of variations in continental water storage – water tables, dams, irrigation. Their more diffuse role also accentuates imbalance.

Historically, it is the post-glacial ice cream rebound that dominated these movements. Today, according to Kiani Shahvandi, the effects induced by human activities already exceed those left by the major climatic cycles of the past.

Concrete impacts on space technology

What is the problem of a variable geographic north pole? Its movement modifies everything “simply” the even benchmark even on which many spatial technologies are based. The axis of terrestrial rotation serves as the basis for identifying positions in space. It defines the land coordinates (terrestrial reference system) and their correspondence with the celestial coordinates. If this axis moves, even slightly, it gradually falters the geolocation of satellites, the trajectory of interplanetary probes and the orientation of space telescopes.

Spatial agencies like NASA or ESA use precise models of terrestrial rotation – incorporating the polar movement – to predict the position of an orbit object to the nearest a few centimeters. However, if the pole moves faster or in a different direction from that provided, these models become less reliable. The necessary corrections are then more frequent and more complex. Especially for navigation systems on board satellites and spacecraft.

In addition, researchers highlight another consequence: the polar tide phenomenon. This type of tide is generated by moving the rotation axis. It leads to slight variations in sea level. These fluctuations, although of the order of centimeter, can induce deformations of the earth's crust up to 2.8 cm in the regions of average latitude by 2100.

These deformations have side effects on the gravimetric measurements made by satellite (such as Grace or Gocal) and can complicate the monitoring of the level of the oceans or variations in the field of terrestrial severity. Ultimately, this could affect the accuracy of climate observations and the internal structures of the planet.

A magnetic field also in full drift

The magnetic North Pole should not be confused with the Geographic North Pole. The first designates the point on the earth's surface where the magnetic field points vertically downwards. It varies in time, because it depends on the dynamics of the terrestrial external nucleus, composed of fusion metals. The second corresponds to the axis of rotation of the earth, relatively fixed in space. But it remains subject to oscillations, like those mentioned above.

Since its discovery in 1831 in the north of Canada, the North magnetic pole has started a slow, but continuous migration. This trip has accelerated sharply in the 1990s. He went from a speed of 15 km/year to a peak of 55 km/year before recently slowing down, according to Arnaud Chulliat, geophysicist at Noaa and the University of Colorado. Today, he heads for Siberia.

This movement is mapped every five years by the World Magnetic Model (WMM). These data is used in particular by GPS systems, air and military navigation. A regular update is essential to maintain the accuracy of the instruments that rely on the Earth's magnetic field. In the absence of readjustment, navigation errors can become significant.

Illusory stability

The North Pole, whether magnetic or geographic, is therefore not a frozen anchor. The first, linked to the flows of the liquid nucleus, evolves according to internal turbulence. The second, influenced by the distribution of masses on the surface of the planet, now also depends on the climate. “” It's not just a matter of astronomy or geophysics. This is a direct consequence of our collective choices “, Recall researchers to Live science.

The precision of forecasts remains limited. This in particular because of the uncertainties on the evolution of global water consumption, on the melting of Asia glaciers or on underground freshwater stocks. However, the trends are clear. If we do not reduce our programs, the physical landmarks of our planet will continue to slip. And with them, a part of our technological mastery of the world.

Source: Kiani Shahvandi, M., & Soja, B. (2025). “Climate-induced Polar Motion: 1900–2100”. Geophysical Research Letters52, E2024GL113405.