Tuesday, February 05, 2019

The magnetic north pole is on the move - should we care?

I have already reported that the Earth's north and south poles are in the process of swapping over, as they do from time to time. But I was nevertheless shocked to learn about the speed of development of another magnetic pole phenomenon.

The magnetic north pole is in the move, and it is moving much faster than it used to. Due to turbulence in the Earth's liquid iron/nickel outer core (which spins at a different rate than the surface, and is subject to all sorts of dynamo effects and convection currents), the northern magnetic pole is moving north at about 55 km a year, headed out of the Canadian Arctic and towards Russian Siberia. Currently, by sheer coincidence, it is hovering quite close to the geographical north pole, deep in the Arctic Ocean. It has moved nearly 2,300 km since it was first identified in 1831, which is quite extraordinary.

It is also moving much faster than it used to: in the last 30 years, it has gone from moving at just 5-10 km per year, to the current 50-60 km per year. Furthermore, it used to move in a much more random fashion, whereas in recent decades it has kept up a steady trajectory towards the northwest. The World Magnetic Model, the main agency that keeps and publishes official records on the magnetic north pole, and funded by the US and UK military, used to issue updates every five years; now, they are having to do it more often.

Now, you might not think this is a big deal - we don't have to reprint all our maps or anything like that, and the geographical north pole is right where it always was - but cellphones, car GPS systems, some consumer electronics, airplanes, ships, and the military all make regular use of the magnetic north pole. Oh, and compasses if anyone still uses those. 

Apparently, for technical reaons that escape me, below a latitude of about 55°N - which is where most people live - the difference are not huge as yet, but for people navigating in the far north, it is beginning to become a major issue. It is also potentially going to have an effect on migratory birds, many of which use the magnetic north to navigate.

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