44. Strange anomaly The South Atlantic Anomaly is an area of weak magnetic field stretching from South America to southern
Africa, captured here by the European Space Agency’s Swarm satellite constellation. The anomaly has been growing and
intensifying over the last 200 years, which could mean that a reversal of the Earth’s magnetic field is on its way. To see if that
might happen, geophysicists have been examining archaeological artefacts to try to decipher how our magnetic history has
changed over the previous 3000 years. (Courtesy: Division of Geomagnetism, DTU Space)
45. The Earth’s magnetic field a The Earth’s magnetic field acts like a giant bar magnet, with the field lines
encircling the planet and protecting it from the solar wind. (Courtesy: Shutterstock/Milagli) b The direction of the
magnetic field at any given point on the Earth’s surface is defined by the declination – the angle on a horizontal
plane between magnetic north and the North Pole. This angle varies across the Earth’s surface and changes
over time, making it of interest to those involved in “archaeomagnetism”
46.
47.
48.
49.
50.
51.
52.
53.
54.
55.
56.
57.
58. Climate change has shifted Earth's POLES: Faster ice
melting under global warming is causing the magnetic north
and south poles to drift around the surface of our planet
59.
60. 1990s turning point: Melting
of glaciers in Alaska,
Greenland, the Southern
Andes, Antarctica, the
Caucasus and the Middle
East accelerated in the mid-
90s, becoming the main
driver pushing Earth’s poles
into a sudden and rapid drift
toward 26°E at a rate of 3.28
millimetres (0.129 inches)
per year. Colour intensity on
the map shows where
changes in water stored on
land (mostly as ice) had the
strongest effect on the
movement of the poles from
April 2004 to June 2020.
Inset graphs plot the change
in glacier mass (black) and
the calculated change in
water on land (blue) in the
regions of largest influence
