World Magnetic Model (WMM) is the standard model for navigation, attitude, and heading referencing systems that use the geomagnetic field.
- New version of model is updated every five years to address changes in Earth’s magnetic field.
- It is produced by the United States’ National Geospatial-Intelligence Agency (NGA) and the United Kingdom’s Defence Geographic Centre (DGC).
Shift in Earth’s Magnetic North Pole
- Magnetic North is where the Earth’s magnetic field lines enter Earth in the North while Geographic North is where lines of longitude (meridians) converge in the north.
- Earth rotates on the geographic north and south poles.
- Since Earth’s Magnetic North Pole was first discovered in 1831 by explorer James Clark Ross, it has gradually shifted.
- Over past century, its movement from Canada toward Siberia (Russia) has accelerated reaching a peak of 31 miles annually by 2000s but rate of movement has slowed in last five years.
- Positions of Earth’s Magnetic North and South Poles gradually change due to variations in Earth’s magnetic field over time.
- Magnetic declination – the angle between magnetic North and Geographic North – at a given location also changes over time.
- Sometimes, Magnetic Poles also undergo Pole Reversal i.e. swapping of magnetic north and south poles.
- According to Paleomagnetic records, Earth’s magnetic poles have reversed 183 times in the last 83 million years.
- Potential Implications: Errors in navigation systems, impact on migratory species, risks from solar storms to satellites and power grids etc.