  The wandering of Earth's north magnetic pole, the location where the magnetic
field points vertically downwards, has long been a topic of scientific
fascination. Since the first in-situ measurements in 1831 of its location in
the Canadian arctic, the pole has drifted inexorably towards Siberia,
accelerating between 1990 and 2005 from its historic speed of 0-15 km/yr to its
present speed of 50-60 km/yr. In late October 2017 the north magnetic pole
crossed the international date line, passing within 390 km of the geographic
pole, and is now moving southwards. Here we show that over the last two decades
the position of the north magnetic pole has been largely determined by two
large-scale lobes of negative magnetic flux on the core-mantle-boundary under
Canada and Siberia. Localised modelling shows that elongation of the Canadian
lobe, likely caused by an alteration in the pattern of core-flow between 1970
and 1999, significantly weakened its signature on Earth's surface causing the
pole to accelerate towards Siberia. A range of simple models that capture this
process indicate that over the next decade the north magnetic pole will
continue on its current trajectory travelling a further 390-660 km towards
Siberia.
