As Earth's magnetic field varies over time, the positions of the North and South Magnetic Poles gradually change. Magnetic declination—the angle between magnetic North and true North—at a given location also changes over time. Our Historical Magnetic Declination Map Viewer displays locations of the geomagnetic poles and historical declination lines calculated for the years 1590–2020.
Earth's Magnetic History
Sir James Clark Ross first discovered the North Magnetic Pole in northern Canada in 1831. Since 1831, the pole has been moving across the Canadian Arctic towards Russia. We’ve calculated the movement of both the North and South Magnetic Poles from 1590 to 2020 using two models: gufm1 and IGRF. Gufm1 incorporates thousands of magnetic observations taken by mariners engaged in merchant and naval shipping. The IGRF is the product of a collaborative effort between magnetic field modelers and the institutes involved in collecting and disseminating magnetic field data from satellites and from observatories and surveys around the world. A recent survey by a Canadian–French international collaboration determined that the Pole is moving approximately north-northwest at 55 km per year.
Plates and Polarity: Synchronicity
Earth’s magnetic field has been slowly changing throughout its existence. When the tectonic plates form along the oceanic ridges, the magnetic field that exists is “frozen” into the rock as they cool below about 700°C. The slowly moving plates act as a kind of tape recorder leaving information about the strength and direction of past magnetic fields. By sampling these rocks and using radiometric dating techniques, it has been possible to reconstruct the history of the Earth's magnetic field for roughly the last 160 million years. If one “plays the tape backwards,” the record shows Earth’s magnetic field strengthening, weakening, and often changing polarity.
We’ve created an animation showing changes in declination location and the “wandering” of the North Magnetic Pole over the last 50 years. Watch how the isogonic lines converge at the Pole. View historic data back to 1590 with our Map Viewer.