IS EARTH’S SHIELD FAILING?
Chaos in Earth’s Interior Could Cause Doomsday Earth’s magnetic field is getting weaker. If it disappears, Earth will be left unprotected against space radiation, and humans will be an endangered species. By means of three satellites, scientists are raci
Between Alaska and Siberia, an underground river is winding from east to west; a river, which is very unlike anything we know from Earth's surface. The fluid is not water, it is liquid iron, which flows at a depth of 3,000 km.
The liquid iron in the 420-km-wide river flows at a speed of up to 5 m/h or 50 km/year. According to scientists from the University of Leeds and the Technical University of Denmark, the speed is increasing. Their data shows that the river is now flowing three times faster than 15 years ago – and faster than in any other place in Earth’s interior. Together with other evidence, the river supports scientists’ suspicion that the core is much more dynamic than previously believed, meaning that Earth’s essential magnetic field is changing fast and that a disastrous pole reversal could be imminent.
EARTH’S SHIELD IS LOSING STRENGTH
The iron river was discovered by the three European Swarm satellites due to variations in the magnetic field, but in the long term, the variations could also be evidence of severe problems for our planet. Scientists know that for the past 2,000 years, the magnetic north pole has been "dancing" around the geographical north pole at a speed of up to 15 km/year. Moreover, the strength of the magnetic field has been reduced by about 10 % since the 1860s, so, scientists are busy trying to understand what produces the field and not least the consequences for mankind, if it is further weakened or disappears completely.
The magnetic field primarily arises due to currents in the exterior, liquid layer of the core. The river of liquid iron, which scientists have just discovered, is a part of the currents and contributes to producing a self-reinforcing dynamo, which is, however, unstable. Geologists have shown that the magnetic field can shut down almost completely and change direction, so instead of pointing north, a
compass would point south. Scientists do not know if we are on our way towards a pole reversal, but they do know that the poles have been reversed several times in Earth’s history – most recently 780,000 years ago. The frequency of pole reversals varies, but on average, they take place every 370,000 years.
A powerful and stable magnetic field is the prerequisite for our civilization. Earth is constantly bombarded with high-energy space particles, which are bent by the magnetic field. Only in the polar regions, where the field lines are more or less vertical, the particles can slip into the upper atmosphere to produce auroras. A weaker magnetic field as a result of pole reversal would mean a weaker space shield, i.e. more particles would slip through the defence to reach Earth’s surface, possibly causing critical computer errors, damaged technology, power supply problems, and not least more cases of severe and fatal diseases.
THE NEANDERTHALS WERE AFFECTED
The cause of pole reversal is not yet known in details. Geologists’ best theory is that at depths of 3,000-5,000 km, local areas occur in which the field is the opposite of the general field. Such an area exists below South Africa, etc. If the areas grow sufficiently large, the general magnetic field is affected, and if so, two scenarios are possible: either the original field reemerges or it is reversed. But in order for areas with reversed magnetic fields to arise, variations in the flow of energy and material in the outer core are required. According to computer simulations of the magnetic field, spontaneous pole reversals cannot occur in a homogenous, symmetrical core. But if the simulations allow for disorder and asymmetry, as exemplified by the river of liquid iron, pole reversals take place over and over again. According to the geological data, a complete pole reversal takes 1,00020,000 years, but the process is not a gradual and smooth one. Instead, the magnetic field is shattered, breaking into many small fields. The consequence of all the small fields is that the world has several magnetic north and south poles at a time. In such a situation, compass navigation is impossible. During a pole reversal, the strength of the magnetic field is reduced by 90+ %. During the centuries or millennia, in which the field is weakest, Earth is subjected to
much more space radiation, and perhaps this has already affected human evolution.
According to French scientists Jean-Pierre Valet and Hélène Valladas, that is the case. In their studies, they focus on a period during the most recent ice age 41,000 years ago, when Europe's Neanderthal population collapsed – at the exact same time as a geomagnetic deviation, during which the magnetic field "prepares" for pole reversal, and the poles might even be briefly reversed, but finally, the magnetic field is reestablished.
That was exactly what happened during the Laschamp event. For about 250 years, the north and south poles changed back and forth, and the strength of the magnetic field was reduced by 95 %, damaging the ozone layer over Europe, so more harmful, cancercausing, ultraviolet radiation from the Sun reached Earth’s surface.
The radiation change is not the complete explanation of the collapse of the Neanderthals, but according to Valet's and Valladas’ theory, the Neanderthals became so weak that they could not handle the pressure of the fast ice age climate change and modern man’s arrival to the continent.
“VERDICT” IN 2034
Knowing this, it is interesting that the present development in Earth’s magnetic field is reminiscent of the early Laschamp event. The field strength is quickly reduced, and the areas of the outer core with reversed magnetization grow. Finally, in a few hundred years, we may experience a period, during which Earth’s space radiation shield will be almost nonexistent.
Italian and Chinese scientists have even fixed a deadline for when we will know if a pole reversal is imminent. If developments in Earth’s core have not been reversed by 2034, a collapse of the magnetic f i eld wi l l be inevitable. So, we should begin to think about how to protect ourselves and our vulnerable technology and power supply, as we would definitely not like to suffer the same fate as the Neanderthals.