. Geomagnetic Reference Models Cannot Keep Pace with the North Magnetic Pole

Abstract
Reference geomagnetic field models such as the World Magnetic Model (WMM) and the International Geomagnetic Reference Field (IGRF) are used in a wide range of applications, including aircraft and ship navigation, and are embedded in billions of handheld electronic devices. Because the main magnetic field slowly changes over time, these models are regularly updated, typically every five years. In early 2018, as part of our regular assessment of the WMM, we found that the model error was on track to exceed its specification before the end of the five-year WMM cycle. We investigated this error and tracked it down to the combined effect of a global geomagnetic acceleration pulse occurring in 2016, and a fast-changing magnetic field in the North polar area. A remarkable manifestation of the field variation is the high-speed drift of the North magnetic pole towards Russia. The pole suddenly accelerated in the 1990s, and has been drifting at about 55 km per year since the beginning of the 21st century. An out-of-cycle update of the WMM has been released to bring the model back into specification.