POLAR WANDER

POLAR WANDER

Subject: Geography

Context: Global warming and melting glaciers could have redistributed the global water fronts to such an extent that they have redefined the ‘polar wander’ or the drifting of the Earth’s axis, finds a study published in Geophysical Research Letters.

Concept:

• Polar wander is the motion of a pole in relation to some reference frame.
• It can be used, for example, to measure the degree to which Earth’s magnetic poles have been observed to move relative to the Earth’s rotation axis.
• True polar wander represents the shift in the geographical poles relative to Earth’s surface, after accounting for the motion of the tectonic plates.
• This motion is caused by the rearrangement of the mantle and the crust in order to align the maximum inertia with the current rotation axis.
• This is the situation with the lowest kinetic energy for the given, unchanging, angular momentum of the earth, and is attained as kinetic energy is dissipated due to the non-rigidity of the earth.