Scientists have detected that the earth’s magnetic field has been significantly weakening over the past six months. Data collated by the European Space Agency (ESA) Swarm satellite array indicates that the field has developed several weak areas over the Western Hemisphere.
Conversely, the field has strengthened in other areas such as the southern Indian Ocean, according to the magnetometers onboard the Swarm satellites.
The magnetic field extends to 370,000 miles (600,000 kilometers) above our planet’s surface, and acts as an invisible shield that acts to protect Earth from lethal blasts of solar radiation. It is thought that the field probably developed shortly after the Earth was formed, and researchers believe that it could have played a signification role in the development of life on the planet.
It exists due to the variations in the metal core at the centre of the Earth, which consists of an iron inner core surrounded by an outer layer of molten metal. Magnetic field lines are created in the outer molten layers when temperature changes combine with the Earth’s rotation to whirl the liquid metal around, forming charged particles The movement of the charged particles through the planet creates a magnetic field as the movement of an electric current through a wire does. The random movements of the boiling metal explain why some areas of the magnetic field strengthen while others weaken, said Florberghagen; fewer currents of magnetically charged particles are released when the movements slow down resulting in a weakness in the surface field. The Swarm array does not just detect signals from the Earth’s magnetic field, but also from its core, mantle, crust and oceans.
“The flow of the liquid outer core almost pulls the magnetic field around with it,” Floberghagen said. “So, a field weakening over the American continent would mean that the flow in the outer core below America is slowing down.”
The reason for the current widespread deterioration in the magnetic field is not yet clear to scientists, but Rune Floberghagen, the ESA’s Swarm mission manager is hopeful that the new satellite data will help determine why it is weakening so rapidly. Floberghagen has suggested that this process is occurring due to an impending polar shift. The Earth’s magnetic poles are known to flip and change direction every few hundred thousand years, meaning that the magnetism at the north pole that drives our compasses would shift to magnetize the south pole.
“Such a flip is not instantaneous, but would take many hundreds if not a few thousand years,” Floberghagen told Live Science. “They have happened many times in the past.”
The last flip happened 780,000 years ago, with the next one originally expected to occur in around 1,500 years, but the frequency is difficult to predict. Scientists know that at one point no polar reversal occurred for 30 million years.
The data originating from Swarm, an array of three separate satellites floating in tandem, suggests that the magnetic field is weakening more quickly than in previous incidents and that the magnetic north is already moving toward Siberia. In the past, it has been estimated that the field typically weakened about 5 percent per century but the new data, which was presented at the Third Swarm Science Meeting in Denmark on June 19, has revealed a progressive weakening of about 5 percent per decade, 10 times faster than expected. If this trend continues, a full polar reversal could happen much sooner than 1,500 years hence.
So what impact could such a polar flip have on the Earth’s inhabitants?
Some people fear that a magnetic switch in the Earth’s poles would result in global cataclysm, causing monumental earthquakes, rapid climate change and species extinctions.In fact, historically the shifts appear to have had little effect, with no available evidence that they caused any type of mass extinction events or resulted in increased radiation damage. In our technologically-evolved existence, scientists believe that the greatest risk would be posed to our power and communication systems, as increased solar storms could damage satellites, cause power outages and interrupt radio communications.
Other, less cataclysmic but nonetheless dangerous effects could affect humans: without protection from the solar bombardment, holes could appear in the atmosphere worsening the already depleted ozone layer, and this would increase the risk of skin cancers. There is also a genuine concern that a weakening and eventual reversal in the field could disorient species that rely on geomagnetism for navigation, such as bees, salmon, turtles, whales, bacteria and pigeons, and scientists are not sure how these creatures could adapt.
The actual timescales involved in the polar shift process are still mostly conjecture, as are the impending effects of this unpredictable event, though the Earth is a very complex system and there is also a possibility that it may never happen at all. It is still hoped that the flip, if it does occur, is still many years in the future, giving researchers time to collate new data and prepare for the eventuality.
In the meantime, scientists hope to make use of the Swarm new data to improve the precision of navigation systems that rely on the magnetic field, such as aircraft instruments. It may also be possible to provide greater accuracy for earthquake predictions as fluctuations in the magnetic field could help identify where continental plates are shifting.