How melting polar ice has warped Earth’s crust

Deformation associated with isostatic rebound is occurring in three dimensions, scientists confirmed.

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The melting of Earth’s polar ice is incrementally warping the planet’s crust both vertically and horizontally, according to a new study in the Geophysical Research Letters journal.

Scientists already knew about a process called isostatic rebound, whereby when a glacier melts, the crust below it is released from the weight previously on top of it, and so very gradually rises up, in some cases over thousands of years.

However, the new study, cited by Sci Tech Daily, adds to this concept, noting that the deformation of the crust is actually three-dimensional, and thus includes horizontal movements as well as vertical ones.

The study adds that rather than simply affecting the areas directly below the ice loss, deformation was also found to have global impacts, with Greenland ice sheet and Arctic glacier melting causing deformation that extends over much of the Northern Hemisphere, for instance.

Case studies showing the incremental scale of the deformation include London, which the study says moved, roughly, between 0.04 and almost 0.2 millimeters vertically every year from 2006 to 2010, plus similar distances to the north and east.

The study’s lead author, Sophie Coulson, explained that we should: “Think of a wooden board floating on top of a tub of water. When you push the board down, you would have the water beneath moving down. If you pick it up, you’ll see the water moving vertically to fill that space.”