by Amy S.
Scientists understand that Earth’s magnetic field has flipped its polarity many times over the millennia. In other words, if you were alive about 800,000 years ago, and facing what we call north with a magnetic compass in your hand, the needle would point to ‘south.’ This is because a magnetic compass is calibrated based on Earth’s poles. The N-S markings of a compass would be 180 degrees wrong if the polarity of today’s magnetic field were reversed. Many doomsday theorists have tried to take this natural geological occurrence and suggest it could lead to Earth’s destruction. But would there be any dramatic effects? The answer, from the geologic and fossil records we have from hundreds of past magnetic polarity reversals, seems to be ‘no.’
Reversals are the rule, not the exception. Earth has settled in the last 20 million years into a pattern of a pole reversal about every 200,000 to 300,000 years, although it has been more than twice that long since the last reversal. A reversal happens over hundreds or thousands of years, and it is not exactly a clean back flip. Magnetic fields morph and push and pull at one another, with multiple poles emerging at odd latitudes throughout the process. Scientists estimate reversals have happened at least hundreds of times over the past three billion years. And while reversals have happened more frequently in “recent” years, when dinosaurs walked Earth a reversal was more likely to happen only about every one million years.
Sediment cores taken from deep ocean floors can tell scientists about magnetic polarity shifts, providing a direct link between magnetic field activity and the fossil record. The Earth’s magnetic field determines the magnetization of lava as it is laid down on the ocean floor on either side of the Mid-Atlantic Rift where the North American and European continental plates are spreading apart. As the lava solidifies, it creates a record of the orientation of past magnetic fields much like a tape recorder records sound. The last time that Earth’s poles flipped in a major reversal was about 780,000 years ago, in what scientists call the Brunhes-Matuyama reversal. The fossil record shows no drastic changes in plant or animal life. Deep ocean sediment cores from this period also indicate no changes in glacial activity, based on the amount of oxygen isotopes in the cores. This is also proof that a polarity reversal would not affect the rotation axis of Earth, as the planet’s rotation axis tilt has a significant effect on climate and glaciation and any change would be evident in the glacial record.
Earth’s polarity is not a constant. Unlike a classic bar magnet, or the decorative magnets on your refrigerator, the matter governing Earth’s magnetic field moves around. Geophysicists are pretty sure that the reason Earth has a magnetic field is because its solid iron core is surrounded by a fluid ocean of hot, liquid metal. This process can also be modeled with supercomputers. Ours is, without hyperbole, a dynamic planet. The flow of liquid iron in Earth’s core creates electric currents, which in turn create the magnetic field. So while parts of Earth’s outer core are too deep for scientists to measure directly, we can infer movement in the core by observing changes in the magnetic field. The magnetic north pole has been creeping northward – by more than 600 miles (1,100 km) – since the early 19th century, when explorers first located it precisely. It is moving faster now, actually, as scientists estimate the pole is migrating northward about 40 miles per year, as opposed to about 10 miles per year in the early 20th century.
Another doomsday hypothesis about a geomagnetic flip plays up fears about incoming solar activity. This suggestion mistakenly assumes that a pole reversal would momentarily leave Earth without the magnetic field that protects us from solar flares and coronal mass ejections from the sun. But, while Earth’s magnetic field can indeed weaken and strengthen over time, there is no indication that it has ever disappeared completely. A weaker field would certainly lead to a small increase in solar radiation on Earth – as well as a beautiful display of aurora at lower latitudes – but nothing deadly. Moreover, even with a weakened magnetic field, Earth’s thick atmosphere also offers protection against the sun’s incoming particles.
The science shows that magnetic pole reversal is – in terms of geologic time scales – a common occurrence that happens gradually over millennia. While the conditions that cause polarity reversals are not entirely predictable – the north pole’s movement could subtly change direction, for instance – there is nothing in the millions of years of geologic record to suggest that any of the 2012 doomsday scenarios connected to a pole reversal should be taken seriously.
There’s a renewed interest right now in Earth’s magnetic poles – specifically, whether or not they’re about to flip, and what may happen. The consequences of this seemingly rapid geomagnetic backflip may sound a little ominous, but don’t worry: we’re not sure when the next reversal will happen, and even when it does, the risks aren’t likely to be as scary as you may think.
Let’s start with the basics.
As Earth’s liquid, iron-rich outer core gradually cools, it sloshes around through colossal convection currents, which are also somewhat warped by Earth’s own rotation. Thanks to a quirk of physics known as the dynamo theory, this generates a powerful magnetic field, with a north and south end.
Although 99 percent of the magnetic energy remains within the core, the slithers that escape extend into space, and spends most of its time deflecting potentially deadly, atmosphere-stripping solar wind.
Right now, the magnetic north pole is exactly where you suspect it is; the same goes for the magnetic south pole. Both represent locales in which the planet’s magnetic field is vertical, and at which point your compass needle tries to point upwards.
Throughout geological time, these magnetic poles have switched sides – a phenomenon known as a “geomagnetic reversal”. Although there are several hypotheses that attempt to explain this, geophysicists are still a little unsure as to why it happens. It’s clearly something to do with turbulence and chaos within the metallic outer core, but the specifics haven’t been nailed down yet.
This is bad news for anyone who enjoys life without radiation sickness.
The Earth’s magnetic field is a barrier which shields us from a lot of harmful solar radiation, attracting cosmic rays towards our planet’s poles so that they shoot harmlessly past us without doing too much damage. If the field were to become weak enough during this transitional period, more radiation would bake the planet than we’re typically used to, which could ultimately render large parts of the Earth uninhabitable for a long time to come.
What’s more, our technology won’t fare too well once the magnetic field begins to weaken—orbital satellites in particular will suffer from solar buffeting without the convenient protection that’s currently provided by the Earth’s magnetic field. Down on the planet itself, things could get hectic too—solar flares would do more damage than normal, overloading power grids, causing computers to fail, and generally running amok.
This wouldn’t be a small global problem that would pass harmlessly afterwards. Because it takes hundreds of years for the planet’s poles to stabilize, entire generations of humans would be constantly affected, unable to use the technology that has become, and will continue to become, such a large part of our lives.
The greatest threat that this poses to humans is via the sun. With a weak magnetic field, we would be far more exposed to CMEs (Coronal Mass ejections), in which flaming hot materials from the Sun are thrown into space at high speeds (around 5,000,000mph), often in the direction of Earth. These would easily create temporary punctures in our ozone layer, causing massive exposure to UV rays. Some scientists predict that skin cancer rates would skyrocket.
Or, nothing happens…
There are some who are quite sure that people would feel absolutely nothing if the poles were to flip. Whilst sleeping, eating our lunch or working out at the gym, the magnetic poles of our planet could reverse, and we’d be none the wiser.
Those who go by this theory often believe that it will be technology that suffers in such a huge magnetic event. We’ve seen before that solar storms can cause huge malfunctions on satellites, interfere with communications, and cause blackouts. The best, and most recent example of this was the 2003 ‘Halloween Storm’ which caused blackouts across Sweden, it was a logistical nightmare for aviation and caused two NASA satellites to temporarily fail.
If humanity wants to continue to survive indefinitely, we’re going to need to come up with some inventive solutions to this problem while we don’t have plenty of time to organize ourselves.
The Coming Blackout Epidemic
The lights may go out sooner than you think.
Every year, millions of people around the world experience major electricity blackouts, but the country that has endured more blackouts than any other industrialized nation is the United States. Over the last decade, the number of power failures affecting over 50,000 Americans has more than doubled, according to federal data.
The looming power failure epidemic
The paper published this September in Routledge’s Journal of Urban Technology points out that 50 major power outages have afflicted 26 countries in the last decade alone, driven by rapid population growth in concentrated urban areas and a rampant “addiction” to high-consumption lifestyles dependent on electric appliances.
Extreme weather and climate change
According to a little-known report last year to the Executive Office of the President by the Council of Economic Advisers and Department of Energy, between 2012 and 2018 the US saw 679 blackouts due to extreme weather events, costing on average $18-33 billion a year. In 2018 alone, the US suffered eleven “billion-dollar” weather disasters.
“The number of outages caused by severe weather is expected to rise as climate change increases the frequency and intensity of hurricanes, blizzards, floods and other extreme weather events,” the report found.
The growing prevalence of extreme weather including droughts due to climate change could also significantly undermine coal, gas and nuclear production, all of which require large inputs of water, to spin and cool turbines in thermal power plants.
The amount of fresh water consumed for world energy production could double in the next 25 years according to the International Energy Agency (IEA). In that fossil fuel-centric scenario, over 50 percent of demand would come from coal-fired power plants, 30 percent from biofuel production, and 10 percent from oil and natural gas production.
Surveying the impacts of past blackouts in the US, China, Canada, Italy, Africa, and many other regions, they show that blackouts can lead to state-rationing of electricity, massive economic losses, the breakdown of manufacturing, food supply shortages, degradation of water purification and waste facilities, and increases in crime rates and civil unrest. Yet they are not fatalistic about the inevitability of such an increasingly dark future.
“There is a possibility of mitigating, but not eliminating, the risk with improved technology,” said Hugh Byrd. Major investments in self-healing ‘smart grids’ and ‘smart metering’ “can assist in reducing demand by providing feedback to users,” but some technologies can also create new risks like “cyber-espionage of the control systems of generators and distributors.”
Growth of global electricity production, is undergoing “a marked slowdown in many industrialized countries of the west,” due to “increasingly high prices of energy that are squeezing demand. Now, the question is: would that lead to blackouts? In short, I think not—not in the short run, at least… Right now, the industrial sector of several western countries is rapidly contracting and the result is reduced consumption. So, right now, as long as things evolve slowly, I would say that I don’t see a blackout danger anywhere in Europe. We should see a gradual reduction of consumption as people become poorer and poorer, and less and less able to afford to pay the electricity bill.”
So whether we face a future of increasing blackouts or declining consumption, the climbing costs of keeping the lights on means more of us might be switching off. But clearly that doesn’t need to be the final verdict: increasing investments in installing smart grids now could prepare us for increased electricity demand in the future.
Hopefully before another major solar event happens, we might at least have the ability to anticipate it. To, at least, mitigate damages, people could be informed of the exact time and nature of the event, lessening panic and chaos. They could also be instructed to stay off the roads, airlines could be entirely shut down, and protective structures could be created/used (or there might be ways for people to maximize safety at home). While these actions wouldn’t ensure safety, being informed would be the key to recovering from the event. NASA is also aware of the potential problems, and is actively researching solutions. The agency says:
[Space weather] is a problem the same way hurricanes are a problem. One can protect oneself with advance information and proper precautions. During a hurricane watch, a homeowner can stay put … or he can seal up the house, turn off the electronics and get out of the way. Similarly, scientists at NASA and NOAA give warnings to electric companies, spacecraft operators and airline pilots before a CME comes to Earth so that these groups can take proper precautions.
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