In a new study published in Geophysical Research Letters, scientists have looked into the process commonly referred to as polar wandering, which sees the two magnetic poles of Earth drift slightly around the planet's surface.
The perpetual drifting from the planet's well-established axis position is believed to occur due to a combination of factors, including the increasing amount of molten iron under Earth's crust.
Yet, there is more than just that, scientists say, citing man-made factors like climate change.
"Faster ice melting under global warming was the most likely cause of the directional change of the polar drift in the 1990s", explained lead researcher Shanshan Deng from the Chinese Institute of Geographic Sciences and Natural Resources Research.
In the new study, Deng's team analysed the extent of the impact of rising terrestrial water storage (TWS) on the level of magnetic polar wandering, with the two parameters closely monitored in one and the same time lapse.
Relying on data from NASA's Gravity Recovery and Climate Experiment (GRACE) mission and estimates of glacier loss and groundwater pumping from the 1980s, the scientists have come to believe that polar drift, which has picked up in speed and scale tremendously in recent times, occurs primarily due to ice melt.
Aside from magnetic wandering, there has also been a directional change in the planet's position, as its magnetic north pole has been changing from westwards to eastwards. The latter was first detected in the late 20th century.
"The faster ice melting under global warming was the most likely cause of the directional change of the polar drift in the 1990s", the researchers explained in their study, adding that contributing factors could well be "unsustainable consumption of groundwater for irrigation and other anthropogenic activities".
The reason such changes are critical is that they affect the distribution of mass on Earth, making our planet spin differently.
As time passes and the drifting continues, the poles move hundreds of kilometres, although it is invisible and unperceivable by Earth's inhabitants. Yet, the process makes it necessary to introduce changes into the World Magnetic Model, which underlies navigation systems such as GPS.
