A mysterious anomaly is causing the Earth’s magnetic field to weaken, between South America and Africa, and scientists don't know why.
Data collected by the European Space Agency (ESA) and published in May 2020 [1] notes that the affected area, known as the South Atlantic Anomaly, has seen the magnetic force weaken by nearly 9 per cent over the last 200 years. Previously, researchers estimated the field was weakening about 5 percent per century, but the new data revealed the field is actually weakening at 5 percent per decade, or 10 times faster than thought. Hundreds of times in Earth’s history, our magnetic field has reversed, switching north and south, in a planetary flip-flop.
As such, rather than a full polar flip occurring in about 2,000 years, as was predicted, the new data suggest it could happen much sooner [the last one took place over 780,000 years ago].
Still, there is no evidence that a weakened magnetic field would result in a doomsday for Earth. During past polarity flips, there were no mass extinctions, or evidence of radiation damage. Researchers think power grids and communication systems would be most at risk.
While the Earth's magnetic field protects humans from solar radiation, the most significant effects of the weakening magnetic field are limited to technical malfunctions, on board satellites and space crafts.
The biggest weak spots in the magnetic field, which extends 370,000 miles (600,000 kilometers) above the planet's surface, have sprung up over the Western Hemisphere, while the field has strengthened over areas like the southern Indian Ocean, according to the magnetometers onboard the Swarm satellites [three separate satellites floating in tandem].
The World Magnetic Model is a modern successor to magnetic field mapping efforts, dating back to 1701, when Edmond Halley first published a magnetic chart. Today’s WMM is developed in a partnership between NOAA’s National Centers for Environmental Information (NCEI) and the British Geological Survey (BGS) and is a joint product of the U.S. National Geospatial-Intelligence Agency (NGA) and the U.K.’s Defence Geographic Centre. Monitoring the magnetic field and maintaining the WMM to support all these applications is a continuous effort for these agencies and one that occasionally poses unexpected and timely challenges.
The latest update, WMM2020, was released in December 2019, and is valid until 31 December 2024.
➥ https://repository.library.noaa.gov/view/noaa/24390
World Magnetic Model Out-of-Cycle Release
➥ https://www.ncei.noaa.gov/news/world...-cycle-release
➥ https://www.ngdc.noaa.gov/geomag/WMM/