The erratic movements of the North Pole resulted from the liquid-iron that the outer core of the Earth is made of, which is also known as the core field. There are some other factors that influence these movements such as the electric currents created by the flow of seawater, and the magnetic minerals in the crust and upper mantle, but compared to those from the core field they are not as big, according to the World Magnetic Model’s report from 2015.
The core field has never been seen, but we can play a visualization game: imagine a bar magnet which is located in the Earth’s center who also has to poles, the south and the north. Seventy percent of the intensity of the magnetic field that the Earth has is what the magnet represents, according to an emeritus professor of Earth and space sciences at the University of Washington, Ronald Merrill, who was not involved in the research mentioned above. In reality, instead of the bar magnet, there are electric currents in the core of the earth which create the magnetic field.
The so-called bar magnet’s intensity is decreasing over time, every 100 years with an additional 7 percent, as mentioned by Merrill to Live Science. The bar magnet also has movement, so he noted that right now it is tilted toward Canada at slightly less than 10 degrees.
The remained 25 percent of the magnetic field comes from another one which can be visualized as bar magnets that move around, according to Merrill. To make it more understandable, the giant central bar magnet loses power, and the other magnetic fields influence the magnetic field of the Earth more intensely. According to Merrill, this is what causes the field to move towards Siberia.