I’ve been avoiding this story (Magnetic polar shifts cause massive global super storms) for awhile, hoping it would simply die, but people keep asking me about it, and I see it appearing on other blogs, so I suppose I’ll have to address it. Mainly what I want to do is present facts about it and let readers make up their own minds.
There has been a lot of worry and hype on this subject. Part of it is fueled by the silly “2012″ thing. Some it has been fueled by people who had been primed for “space storms” in solar cycle 24, such as in this Fox News video:
Many people still haven’t got the memo that solar cycle 24 is now forecast by NASA (after a number of forecast reductions) to be about as quiet as the Dalton Minimum, with a peak sunspot count of 59 in their latest forecast. They hear that the protective Earth’s magnetic field may flip/deplete from one source, remember the hype over the upcoming solar cycle, and worry that we are going to get toasted. I assure you, we will, when the sun turns into a red giant a couple billion years from now, but let’s not worry about that.
In the meantime, yes, at some point the Earth’s magnetic field will flip. Compasses will point south instead of North. According to the best science we have this happens frequently on Earth (in the scale of geologic time). And, as we know, the sun’s magnetic field appears to reverse its polarity on the advent of each new solar cycle, about every 11 years. The sun doesn’t wink out or get stormy when this happens, nor can we as humans detect any earthly change when this occurs. It’s essentially imperceptible to us.
As for earth, it’s magnetic field also flips, but not nearly as often. About every 200,000-250,000 years. The last one occurred 780,000 years ago, so the period is not constant. This is to be expected in a chaotic system. Below, see the magnetic record timeline as derived from rocks:
More on the magnetic timeline here. Looking at the long term record, magnetic field reversals are rather common. So, as far as Earth goes, it is “business as usual”. It probably would say: “Nothing to see here, move along.” if asked. I’ll point out that life continued through all of this. And, as far as I know, no scientist has linked extinctions to reversals. The Wikipedia article has this to say:
Because the magnetic field has never been observed to reverse by humans with instrumentation, and the mechanism of field generation is not well understood, it is difficult to say what the characteristics of the magnetic field might be leading up to such a reversal.
Some speculate that a greatly diminished magnetic field during a reversal period will expose the surface of the Earth to a substantial and potentially damaging increase in cosmic radiation. However, Homo erectus and their ancestors certainly survived many previous reversals, though they did not depend on computer systems that could be damaged by large coronal mass ejections.
There is no uncontested evidence that a magnetic field reversal has ever caused any biological extinctions. A possible explanation is that the solar wind may induce a sufficient magnetic field in the Earth’s ionosphere to shield the surface from energetic particles even in the absence of the Earth’s normal magnetic field. Another possible explanation is that magnetic field actually does not vanish completely, with many poles forming chaotically in different places during reversal, until it stabilizes again.
There’s a NASA story on the wandering magnetic North pole from 2003 that is instructive, I’m repeating part of it below:
Scientists have long known that the magnetic pole moves. James Ross located the pole for the first time in 1831 after an exhausting arctic journey during which his ship got stuck in the ice for four years. No one returned until the next century. In 1904, Roald Amundsen found the pole again and discovered that it had moved–at least 50 km since the days of Ross.
The pole kept going during the 20th century, north at an average speed of 10 km per year, lately accelerating “to 40 km per year,” says Newitt. At this rate it will exit North America and reach Siberia in a few decades.
Keeping track of the north magnetic pole is Newitt’s job. “We usually go out and check its location once every few years,” he says. “We’ll have to make more trips now that it is moving so quickly.”
Earth’s magnetic field is changing in other ways, too: Compass needles in Africa, for instance, are drifting about 1 degree per decade. And globally the magnetic field has weakened 10% since the 19th century. When this was mentioned by researchers at a recent meeting of the American Geophysical Union, many newspapers carried the story. A typical headline: “Is Earth’s magnetic field collapsing?”
Probably not. As remarkable as these changes sound, “they’re mild compared to what Earth’s magnetic field has done in the past,” says University of California professor Gary Glatzmaier.
Sometimes the field completely flips. The north and the south poles swap places. Such reversals, recorded in the magnetism of ancient rocks, are unpredictable. They come at irregular intervals averaging about 300,000 years; the last one was 780,000 years ago. Are we overdue for another? No one knows.
Left: Magnetic stripes around mid-ocean ridges reveal the history of Earth’s magnetic field for millions of years. The study of Earth’s past magnetism is called paleomagnetism. Image credit: USGS. [more]
According to Glatzmaier, the ongoing 10% decline doesn’t mean that a reversal is imminent. “The field is increasing or decreasing all the time,” he says. “We know this from studies of the paleomagnetic record.” Earth’s present-day magnetic field is, in fact, much stronger than normal. The dipole moment, a measure of the intensity of the magnetic field, is now 8 × 1022 amps × m2. That’s twice the million-year average of 4× 1022 amps × m2.
To understand what’s happening, says Glatzmaier, we have to take a trip … to the center of the Earth where the magnetic field is produced.
At the heart of our planet lies a solid iron ball, about as hot as the surface of the sun. Researchers call it “the inner core.” It’s really a world within a world. The inner core is 70% as wide as the moon. It spins at its own rate, as much as 0.2° of longitude per year faster than the Earth above it, and it has its own ocean: a very deep layer of liquid iron known as “the outer core.”
Earth’s magnetic field comes from this ocean of iron, which is an electrically conducting fluid in constant motion. Sitting atop the hot inner core, the liquid outer core seethes and roils like water in a pan on a hot stove. The outer core also has “hurricanes”–whirlpools powered by the Coriolis forces of Earth’s rotation. These complex motions generate our planet’s magnetism through a process called the dynamo effect.
Using the equations of magnetohydrodynamics, a branch of physics dealing with conducting fluids and magnetic fields, Glatzmaier and colleague Paul Roberts have created a supercomputer model of Earth’s interior. Their software heats the inner core, stirs the metallic ocean above it, then calculates the resulting magnetic field. They run their code for hundreds of thousands of simulated years and watch what happens.
What they see mimics the real Earth: The magnetic field waxes and wanes, poles drift and, occasionally, flip. Change is normal, they’ve learned. And no wonder. The source of the field, the outer core, is itself seething, swirling, turbulent. “It’s chaotic down there,” notes Glatzmaier. The changes we detect on our planet’s surface are a sign of that inner chaos.
They’ve also learned what happens during a magnetic flip. Reversals take a few thousand years to complete, and during that time–contrary to popular belief–the magnetic field does not vanish. “It just gets more complicated,” says Glatzmaier. Magnetic lines of force near Earth’s surface become twisted and tangled, and magnetic poles pop up in unaccustomed places. A south magnetic pole might emerge over Africa, for instance, or a north pole over Tahiti. Weird. But it’s still a planetary magnetic field, and it still protects us from space radiation and solar storms.
Above: Supercomputer models of Earth’s magnetic field. On the left is a normal dipolar magnetic field, typical of the long years between polarity reversals. On the right is the sort of complicated magnetic field Earth has during the upheaval of a reversal. [more]
They didn’t seem very worried about it at NASA then. They were more worried about solar cycle 24 producing a lot of solar flares at the time, which would disrupt a lot of our new technology.
When a big CME heads toward earth, it can cause havoc, whether our magnetic field is strong or not. For example, in 1859, long before our worries about Earth’s magnetic field started, there was the Carrington event:
At 11:18 AM on the cloudless morning of Thursday, September 1, 1859, 33-year-old Richard Carrington—widely acknowledged to be one of England’s foremost solar astronomers—was in his well-appointed private observatory. Just as usual on every sunny day, his telescope was projecting an 11-inch-wide image of the sun on a screen, and Carrington skillfully drew the sunspots he saw.
Right: Sunspots sketched by Richard Carrington on Sept. 1, 1859. Copyright: Royal Astronomical Society: more.
On that morning, he was capturing the likeness of an enormous group of sunspots. Suddenly, before his eyes, two brilliant beads of blinding white light appeared over the sunspots, intensified rapidly, and became kidney-shaped. Realizing that he was witnessing something unprecedented and “being somewhat flurried by the surprise,” Carrington later wrote, “I hastily ran to call someone to witness the exhibition with me. On returning within 60 seconds, I was mortified to find that it was already much changed and enfeebled.” He and his witness watched the white spots contract to mere pinpoints and disappear.
It was 11:23 AM. Only five minutes had passed.
Just before dawn the next day, skies all over planet Earth erupted in red, green, and purple auroras so brilliant that newspapers could be read as easily as in daylight. Indeed, stunning auroras pulsated even at near tropical latitudes over Cuba, the Bahamas, Jamaica, El Salvador, and Hawaii.
Even more disconcerting, telegraph systems worldwide went haywire. Spark discharges shocked telegraph operators and set the telegraph paper on fire. Even when telegraphers disconnected the batteries powering the lines, aurora-induced electric currents in the wires still allowed messages to be transmitted.
“What Carrington saw was a white-light solar flare—a magnetic explosion on the sun,” explains David Hathaway, solar physics team lead at NASA’s Marshall Space Flight Center in Huntsville, Alabama.
Notice, no mention in any of the historical reports of superstorm style bad weather, just unusual low latitude auroras and wacky telegraphs. Such an event will happen again in Earth’s history, we can be sure of it. From Wiki: “Ice cores contain thin nitrate-rich layers that can be used to reconstruct a history of past events before reliable observations. These show evidence that events of this magnitude — as measured by high-energy proton radiation, not geomagnetic effect — occur approximately once per 500 years, with events at least one-fifth as large occurring several times per century. Less severe storms have occurred in 1921 and 1960, when widespread radio disruption was reported”
Sure, it would be worse today if Earth’s magnetic field was weaker, but comparatively, the terrestrial magnetic field is a wimp and get’s pushed around by the sun anyway:
Now compare that story to what our buddy
Caca Kaku has been saying:
But for now, the reality of solar cycle 24 is far less worrisome:
Adding to some of the media hype worry, the north magnetic pole is on the move. In fact, as Luboš Motl has recently pointed out, it has been accelerating in its movement. According to this 2009 NatGeo story, it is now on the move by about 40 miles per year towards Siberia:
There was the recent story about runways at Tampa International Airport having to be renumbered because the compass heading has changed. It also added to the worry and hype about the Earth’s magnetic field. Well, it is a story that is likely to be repeated in the years to come, as the pole drifts even more. At some point the FAA may just decide it isn’t worth trying to keep up with, and make runway numbers reflect GPS headings (based on true north) instead.
And that’s not the only effect. Soon, many USHCN and GHCN ASOS station in the USA will be out of alignment with magnetic north. Yes that’s right, they are aligned perpendicular to magnetic north, like this US Historical Climate Network climate monitoring station in Minneapolis, MN:
There’s of course the possibility that a weaker magnetic field might provide for some increased thunderstorm development, such as this linkage between Forbush decreases and thunderstorm electricity, but there doesn’t appear to be any strong linkage to synoptic scale storm formation that we know of. The issue of the sun modulating cosmic ray passage to Earth which is a different issue altogether.
Now compare what has been presented above to the article in Helium that everyone is concerned about:
On the heels of the lashing the British Isles sustained, monster storms began to pummel North America. The latest superstorm—as of this writing—is a monster over the U.S. that stretched across 2,000 miles affecting more than 150 million people.
Yet even as that storm wreaked havoc across the Western, Southern, Midwestern and Northeastern states, another superstorm broke out in the Pacific and closed in on Australia.
The southern continent had already dealt with the disaster of historic superstorm flooding from rains that dropped as much as several feet in a matter of hours. Tens of thousands of homes were damaged or destroyed. After the deluge bull sharks were spotted swimming between houses in what was once the quiet town of Goodna.
Shocked authorities now numbly concede that some of the water may never dissipate and have wearily resigned themselves to the possibility that region will now contain a small inland sea.
But then only a handful of weeks later another superstorm—the mega-monster cyclone Yasi—struck northeastern Australia. The damage it left in its wake is being called by rescue workers a war zone.
Do you recognize the writing style? Let’s look at a similar example.
We have recently been told that these storms were caused by “man-made global warming”, let’s listen to Al Gore:
As it turns out, the scientific community has been addressing this particular question for some time now and they say that increased heavy snowfalls are completely consistent with what they have been predicting as a consequence of man-made global warming:
“In fact, scientists have been warning for at least two decades that global warming could make snowstorms more severe. Snow has two simple ingredients: cold and moisture. Warmer air collects moisture like a sponge until it hits a patch of cold air. When temperatures dip below freezing, a lot of moisture creates a lot of snow.”
“A rise in global temperature can create all sorts of havoc, ranging from hotter dry spells to colder winters, along with increasingly violent storms, flooding, forest fires and loss of endangered species.”
There’s a catastrophe prediction on every street corner it seems:
Me, I’m not worried about the magnetic field flipping any more than I am about the sun turning into a red giant. It’s out of my hands. The best you can do is to adopt the old Boy Scout motto: Be prepared.
For what, I’m not sure, so I don’t worry too much. Nature so far has allowed life to go along on this planet, mostly unabated for millions of years. Sure, we could get squished like a bug tomorrow by an asteroid, but can we do anything about that if we know today?
Bobby McFerrin had it right: