Remember when you were a student pilot prepping for the cross-country flights with a sectional chart, using your plotter to calculate the true course to the destination? Then using magnetic variation (east is least, west is best) to get magnetic course. GPS navigation and all our apps have changed that, but the basics remain.
You might have missed how much the magnetic variation is changing. What makes the basics interesting is that the magnetic poles have recently been moving faster. For most of the period going back to 1832, the movement of the magnetic north pole has drifted along at about 15 kilometers per year. But since the mid-1990s it has accelerated to 55 kilometers per year. Additionally, the magnetic field strength has been decreasing. According to the European Space Agency (ESA), the magnetic field has lost nearly nine per cent of its strength on a global average in the last 200 years. The field strength decrease in the South Atlantic is even more, causing this area to be labeled the South Atlantic Anomaly.
