Apocalypse Now: Scientists Predict the Earth is About to Swap Magnetic Poles

The Earth is protected from harmful cosmic radiation by a magnetic field, which deflects charged particles away from the planet. However, this force is not constant. In the entire history of the planet, there have been at least several hundred reversals of the magnetic field, when the north and south magnetic poles switched places.

During the reversal of the poles, the magnetic field changes shape and weakens. During this period, it may drop to ten percent of its original strength and simultaneously form more than two poles, even on the equator. On average, magnetic field reversals occur once in a million years, but the interval between them isn't permanent.

Besides full geomagnetic reversals, there have been partial reversals in Earth's history, when the magnetic poles moved to lower latitudes, until crossing the equator and then returning back. The last full reversal, the so-called Brunhes-Matuyama phenomenon happened about 780,000 years ago. A temporary reversal, the Laschamp event, occurred 41,000 years ago and lasted less than a thousand years, the scientists wrote.

During the reversals, changes in the magnetic field weaken the protection of the planet and raise the level of radiation. If a geomagnetic reversal occurred today, it would increase risks for near-Earth satellites, aircraft and ground-based electrical infrastructure. Geomagnetic storms arising from a harsh increase of solar activity give scientists an opportunity to assess the threats that the planet could face in the event of a sharp weakening of its magnetic field.

In 2003, the so-called Halloween solar storm caused blackouts of electric networks in Sweden and necessitated changes in air travel routes that helped to avoid temporary communication failures and reduce radiation risks for the satellites and ground systems. But this storm is considered to be negligible in comparison with the Carrington event, the geomagnetic storm of 1859, when the Northern lights occurred even around the Caribbean islands, the geophysicists stated.

Meanwhile, the impact that a major storm can produce to a modern electronic infrastructure is still unclear. The definite economic damage from blackouts of power, heating, air conditioning, GPS and the Internet would be quite significant: using approximate calculations, it is estimated to at least 40 billion dollars per day.

The direct effect which a reversal of the magnetic field would produce on living beings and humans is also difficult to predict: modern man hasn't faced such an event in the history of his existence. Some studies try to link geomagnetic reversals and volcanic activity with mass extinctions; however, Mound and Livermore note that there is no noticeable activation of volcanism yet. So it's most likely that humanity will only have to deal with electromagnetic exposure.

It is known that many species of animals have some form of magnetoreception, which allows them to feel the change in the magnetic field of the Earth. The animals use this feature for navigation during long migrations, but it is unclear what impact the geomagnetic reversals would exactly have on these species. It is only known that the ancient people managed to survive the Laschamp event, and other forms of life on the planet faced complete geomagnetic reversals hundreds of times.

Two factors — the remoteness of the Brunhes-Matuyama event and the observed weakening of the Earth's geomagnetic field by about five percent in a century — allow the scientists to cautiously assume that the reversal may occur within the next two thousand years. The exact timing is difficult to predict.

After having lived thousands of years on Earth, people still know little about it. The scientists have only approximate information on the composition and structure of the Earth's core, which generates the magnetic field. Just recently, in laboratory experiments simulating conditions within the Earth, Japanese scientists established that its third major component is silicon. It makes up approximately five percent of the mass of the Earth's core; the rest is iron (85 percent) and nickel (10 percent).

The effect the magnetic field has on the planet presents the largest geophysical problem. It isn't fully known how the planet maintains its own magnetosphere. Scientists have only one theory that offers an explanation: geodynamo. According to this theory, there is a metallic core with a hard shell and liquid center in the center of the planet. Due to the decay of radioactive elements,  heat is generated, which leads to the formation of the convective flow of a conducting fluid. These currents generate  the magnetic field of the planet.

Although the geodynamo theory has no alternatives, it prompts some questions. According to classical magneto-hydrodynamics, the dynamo effect should fade, and the core of the planet should cool down and harden. There is no exact understanding of the mechanisms by which the Earth supports the self-generation of the dynamo effect, together with the observed features of the magnetic field, geomagnetic anomalies, migration and the reversal of the poles.

As noted by Mound and Livermore, the recent discovery of a jet-stream within the core shows the growing possibilities of science in the study of the dynamics of the planet's interior processes. The Jet-stream was formed in the liquid outer core of the Earth in an area under the North Pole. The width of the object at the moment is 420 kilometers. It reached such dimensions starting from 2000, and every year increases up to 40 kilometers in width.

Geophysicists believe that the jet-stream which was discovered is one of the objects that create a magnetic field of the Earth. In combination with numerical methods and laboratory experiments, this and other discoveries, according to experts, should greatly accelerate progress in geophysics. Scientists will soon be able to predict the behavior of the Earth's core, Mound and Livermore noted.