Earth’s north magnetic pole is drifting south toward Siberia at an accelerating rate, according to recent data from the European Space Agency (ESA), which also showed that the dynamic magnetic field that protects the planet from radiation has weakened.
The ESA at a conference in Copenhagen this week presented its first high-resolution results from its three-satellite Swarm mission, which was launched in November 2013 and aimed to investigate changes in Earth’s magnetic field, which acts as a shield against solar and space radiation and moderates the climate.
Measurements taken over the past six months by Swarm satellites confirmed that Earth’s magnetic field is weakening, with dramatic declines over the Western Hemisphere. The field is produced by electrical currents generated deep within the planet’s core, and it constantly changes in strength and orientation.
Over the past two centuries, Earth's magnetic field has weakened by 15 percent, according to scientists. Risks of a weak magnetic field include more deaths from cancer due to increased radiation, electrical grid collapse from severe solar storms, climate change and temporary ozone holes.
The data showed that Earth’s north magnetic pole — different from the geographic North Pole, which marks Earth’s rotational axis — is moving south. Since magnetic north was first located in 1831, it has wandered more than 600 miles.
In recent years, its movement has accelerated, from an average of six miles a year to 25 miles, and scientists predict it could travel from its current position in North America to Asia within a few decades.
Magnetic pole reversals occur on average every 200,000 to 300,000 years, and the magnetic field weakening observed by Swarm could indicate an upcoming pole shift. The last reversal was about 780,000 years ago.
Such shifts usually take thousands of years, but some scientists believe they have found evidence that they happen much more rapidly. In cases of rapid shifts, the reversed polarity was short and temporary.