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North Magnetic Pole Racing Toward Siberia
RogerRoast sends along a backgrounder from Scientific American on the best current theory as to why the north magnetic pole drifts. "The NMP, also known as the dip pole, is the point on Earth where the planet's magnetic field points straight down into the ground. Scottish explorer James Clark Ross first located the NMP in 1831 on the Boothia Peninsula in what is now northern Canada... [T]he NMP drifts from year to year as geophysical processes within Earth change. For more than 150 years after Ross's measurement its movement was gradual, generally less than 15 kilometers per year. But then, in the 1990s, it picked up speed, ... bolting north–northwest into the Arctic Ocean at more than 55 kilometers per year. If it keeps going it could pass the geographic north pole in a decade or so and carry on toward Siberia."
Parent is wrong. Ordnance Survey maps are NOT magnetic north aligned. They are aligned to OS Grid North, which is fixed wrt the UK (but not congruent with True North). Each printed map sheet has a diagram indicating the deviation from grid north of magnetic north at the centre of the sheet at a given epoch. When taking a bearing with a protractor compass, it is necessary to account for the magnetic deviation before following that bearing (in Scotland, magnetic north is currently 2 deg west of grid north).