Magnetic North Pole Has Drifted A Thousand Miles. But North Pole, Alaska? It's Still At Mile 349 Richardson

 Things Poles Apart that Are Not Political... Not Yet, at Least  There's the geographic North Pole, & the Magnetic North Pole. And t...

 Things Poles Apart that Are Not Political... Not Yet, at Least 

There's the geographic North Pole, & the Magnetic North Pole. And then there's our North Pole – up the Richardson Highway, here in Alaska. (Journal file photo)

I was startled today when I checked on the current position of earth’s North Magnetic Pole, particularly since the last time I checked on it was decades ago.  I was surprised to see that it has moved about a thousand miles since then.  This also raised a question about how that may have affected the position of the Northern Lights.  Turns out these two things are not as directly related as I assumed.  

As a Boy Scout over 60 years ago, I learned that the North Magnetic Pole, the point to which compasses are supposed to point, was not aligned with the geographic North Pole, the northern end of the earth’s rotational axis, the literal top of the world.  That separation meant that from my home in the Washington, DC, area, I had to correct compass readings by about fifteen degrees to the east to point to true North.  This difference, known as magnetic declination, is indicated on US Geological Survey topographic maps by a small angle diagram in each map’s margin, and it can differ substantially from one map to another because of location.  

At that time, 1958 or so, the North Magnetic Pole was just southwest of Bathurst Island in the Canadian Arctic Archipelago.  A family friend, Mike Rose, in Anchorage, Alaska, would have had to correct his compass readings about 30 degrees to the west for true North.  

Since then, the North Magnetic Pole has drifted northward, increasingly more rapidly, passing within 240 miles of the North Pole, then southward toward Siberia.  The current local correction from Washington, while still to the east, has decreased to about 10 degrees, while Anchorage’s has also shifted eastward, some thirty-five degrees.   

In reality, compasses don’t point to the North Magnetic Pole.  Instead, they align with the local lines of the earth’s magnetic field.  Those field lines connect the North and South Magnetic Poles but are also affected by local magnetic anomalies.

The reason the pole is shifting is not completely understood, although more so recently.  It appears to be due to a tug of war between two large magnetic anomalies, one under Canada and the other under Siberia, and changes in their relative strengths over time.  

As to the Northern and Southern Lights, the aurora borealis and aurora australis, they most often occur in two oval rings, of about 25 degrees radius, where the farther out magnetic field lines dip into the upper atmosphere as they converge on their respective poles.  The question is which poles?  In fact, neither the magnetic poles nor the geographic poles, but rather the North and South Geomagnetic Poles.  These are calculated points where the “+” and “-“  poles of the hypothetical bar magnet that lies within the earth and generates its magnetic field touch the surface.  The auroral ovals seem to center more on those poles, which also move, but not nearly as far, as rapidly, or as erratically as the magnetic poles.  During my seventy plus years on earth, the North Geomagnetic Pole has moved maybe 100 miles northward along a line between Qaanaaq, formerly Thule, Greenland, and northern Ellesmere Island, in Nunavut, Canada.  As it turns out, this pole is obliquely approaching Alert, on Ellesmere’s northeast coast, where I spent the summer of 1967 at a weather station.  The Magnetic North Pole at that time lay close to Resolute Bay, on Cornwallis Island, where I stayed temporarily at another weather station on either end of that summer.  During the summer I also flew 500 miles south for a day at Thule Air Force Base, blissfully unaware of the existence of or my proximity to the North Geomagnetic Pole.

As a scout I was curious about what a compass would do if it passed over the North Magnetic Pole, perhaps turn in circles?  I didn’t have the opportunity to test that when in the Arctic, but the magnetic pole is ill defined at the surface, with very weak horizontal field lines at higher magnetic latitudes, so the compass needle would want to point down without a definitive place to point.  Therefore, magnetic compasses are useless in polar regions, where celestial navigation is more reliable if the sun or the heavens are visible and if you have a reliable clock time, which gets problematic at the geographic poles, where time zones converge.

The upshot of all this is that the normal position of the Northern Lights has not shifted significantly over this time, but it still may in the future.  Then there’s the fact that we’re overdue for a magnetic pole reversal, when the + and - direction of earth’s magnetic field flips and those polarities switch places.  These reversals are very common in geologic history, although not necessarily uniform in duration.  The last one occurred 780,000 years ago and the one before that 22,000 years earlier.  A previous one was recently determined to have lasted only 200 years.  That’s years, not thousands or ten of thousands of years.  What would be the effect of a reversal?   That’s a question for another time, maybe days or years from now.   

– By David Mudrick, Country Journal official cartoonist & former Gakona resident


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