Despite accelerated movement over the past century, the possibility that Earth's modestly fading magnetic field will collapse is remote. But the shift could mean Alaska may no longer see the sky lights known as auroras, which might then be more visible in more southerly areas of Siberia and Europe.
This is all part of something described as a Polar Drift which is a geological phenomenon caused by variations in the flow of molten iron (magma) in the Earth's outer core, resulting in changes in the orientation of Earth's magnetic field, and hence the position of the magnetic north pole.
The magnetic north pole is approximately 965 kilometers from the geographic north pole. The pole drifts considerably each day, and moves about 10 to 40 km per year as a result of this phenomenon.
In early times European navigators believed that compass needles were attracted either to a "magnetic mountain" or "magnetic island" somewhere in the far north, or to the Pole Star. The idea that the Earth acts as a giant magnet was first proposed in 1600 by Sir William Gilbert, a courtier of Queen Elizabeth I. He was also the first to define the North Magnetic Pole as the point where the Earth's magnetic field points vertically downwards. This is the definition used today, though it would take several hundred years before the nature of the Earth's magnetic field was properly understood.
Most scientists would agree, that even today, we know very little about this subject. Scientists have long known that magnetic poles migrate and in rare cases, swap places. Exactly why this happens is a mystery.
"This may be part of a normal oscillation and it will eventually migrate back toward Canada," Joseph Stoner, a paleomagnetist at Oregon State University, said at a recent American Geophysical Union meeting in December.
Previous studies have shown that the strength of the Earth's magnetic shield has decreased 10 percent over the past 150 years. During the same period, the north magnetic pole wandered about 685 miles out into the Arctic, according to a new analysis by Stoner.
The rate of the magnetic pole's movement has increased in the last century compared to fairly steady movement in the previous four centuries. At its current rate the pole could move to Siberia within the next half-century, Stoner said. "It's moving really fast," he said. "We're seeing something that hasn't happened for at least 500 years."
The north magnetic pole was first discovered in 1831 and when it was revisited in 1904, explorers found that the pole had moved 31 miles.
At the same time the South Magnetic Pole is constantly shifting due to changes in the Earth's magnetic field. As of 2005 it was calculated to lie just off the coast of Wilkes Land, Antarctica. That point lies outside the Antarctic Circle. It is moving north west by about 10 to 15 kilometers per year.
The shift is likely a normal oscillation of the Earth's magnetic field, Stoner said, and not the beginning of a flip-flop or “reversal” of the north and south magnetic poles, a phenomenon that last occurred 780,000 years ago.
Such reversals have taken place 400 times in the last 330 million years, according to magnetic clues sealed in rocks around the world. Each reversal takes a thousand years or more to complete.
Lorne McKee, a geomagnetic scientist at Natural Resources Canada, says that Stoner's data fits his own readings.
"The movement of the pole definitely appears to be accelerating," he said.
But Stoner added, "People like to think something special is happening in their lifetimes, but despite the dramatic changes, I don't see any evidence of it…it's probably just a normal wandering of the pole."
But one can’t help but wonder if the movement of the magnetic poles and the variations in the flow of magma in the Earth's outer core isn’t somehow a contributor to global waming and climate change.
In fact scientists have just discovered that magma may be a contributing factor to why Greenland 's ice is melting. They are presently exploring a thin spot in the Earth's crust, which is enabling underground magma to heat the ice. They have found at least one “hotspot” in the northeast corner of Greenland.
The researchers don't yet know how warm the hotspot is. But if it is warm enough to melt the ice above it even a little, it could be lubricating the base of the ice sheet and enabling the ice to slide more rapidly out to sea.
“The behavior of the great ice sheets is an important barometer of global climate change,” said Ralph von Frese, leader of the project and a professor of earth sciences at Ohio State University. “However, to effectively separate and quantify human impacts on climate change, we must understand the natural impacts, too.
“Crustal heat flow is still one of the unknowns — and it's a fairly significant one, according to our preliminary results.”
To measure actual temperatures beneath the ice, scientists must drill boreholes down to the base of the ice sheet a mile or more below the ice surface. The effort and expense make such measurements few and far between, especially in remote areas of northeast Greenland.
For now, the researchers are combining theories of how heat flows through the mantle and crust with the gravity and radar data, to understand how the hotspot is influencing the ice.
“Recent observations indicate that the Greenland Ice Sheet is much more active than we ever believed,” van der Veen said. “There have been rapid changes in outlet glaciers, for example. Such behavior is critically linked to conditions at the ice bed. Geothermal heat is an important factor, but until now, our models have not included spatial variations in heat, such as this hotspot.
Once they finish searching the rest of Greenland for other hotspots, they hope to turn their attention to Antarctica.
I would suspect we will be hearing more about these new scientific discoveries that will always include a question: How much is human activity contributing to these planetary changes?
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Don Elzer writes and comments about travel, current affairs and the natural world. He is the Director of the Wildcraft Forest Ecomuseum and is the editor of The Monster Guide which can be found at www.themonsterguide.com
He can also be reached by email at: treks@uniserve.com
