How a Geomagnetic Reversal Could Kill All Technology

When Chinese scientists created the first compass sometime between 2 B.C. and 1 A.D., they failed to harness the most important application--directionality. Instead, they used it to arrange furniture and buildings according to feng shui, an ancient Chinese custom that oriented objects to be in harmony with the human spirit. Their compasses were simple constructions: small lodestone spoons placed on a bronze square that always would always point in the same direction.

Despite its delayed development, the compass remains one of the simplest and most relied on inventions ever. Its steady aim has pointed north for the last 40,000 years. But recent evidence suggests that compasses may be pointing south sometime soon.

According to the European Space Agency's Swarm satellite array, the Earth's geomagnetic field is weakening 10 times faster than expected. Scientists expect that the geomagnetic field weakens about 5% per century; in fact, it's weakening 5% per decade. This supposedly indicates an impeding geomagnetic reversal. A brief reversal occurred during the last ice age (38,000 B.C.), but the last permanent reversal occurred 780,000 years ago.

Earth's diamagnetism is caused by an inner core of solid iron and outer core of liquid iron. This outer core displays typical convective properties, and in conjunction with Earth's rotation natural rotation, generates a natural magnetic field.

So what are the implications of a geomagnetic reversal, if it will indeed take place in the next 2,000 years?

First, it depends on how quickly the reversal takes place. One hypothesis is that reversals take at least about 1,000 years, as the Earth's mantle, which is a semiconductor, is thought to act as a two-pass filter and regulates how quickly the polarity transition can occur. Recent paleomagnetic evidence suggests that the polarity can shift up to 6° per day. A slow transition from north-to-south, south-to-north could probably be accounted for by modern navigation equipment (GPS seems to be unaffected), but during the reversal magnetic poles may spontaneously appear and disappear, meaning compasses would be useless until the shift is complete.

The magnetic field also shields Earth from harmful high-energy radiation particles and is a major reason why our planet retains an atmosphere, but a shift is not likely to affect either of these functions. It's also difficult to correlate extinction events with polarity reversals, so it doesn't appear that the human race is threatened by a geomagnetic shift, even though it may inspire increased volcanic activity. Animal migrations might be minimally affected, but most animals use a variety of senses and methods to complete annual migrations.

So far so good--the geomagnetic shift has done nothing but make some outdated compasses act funny. But there could be impacts on our infrastructure.

While power grids won't be initially disturbed (as current is induced when a conductor is in relative motion to a magnetic field), there is a good chance that a strong solar storm could knock out electricity feeds around the world. Take for example the March 1989 geomagnetic storm which knocked out power in Quebec. Since the province sits atop the Canadian Shield, surface-level strength of the geomagnetic field is weaker than in other locations. The result is a geomagnetic induced current which flows through any conductive structure: power lines, pipelines, railways, etc. Nearly any connected piece of equipment could be destroyed if the current is sufficient and the magnetic field is weak enough at a particular time.

Scientists are currently monitoring the natural progression of magnetic north across the Canadian arctic-in ten years it could be located in Russia. This migration should help predict when the next geomagnetic reversal occurs. We know that immediate results of a magnetic shift will be minimal. But it could be that with a weakened magnetic field and a solar storm of epic magnitude, the technology of the future will be blasted back to a metaphorical stone-age because of a phenomena our species has never witnessed.