Ice Melt is Causing the Earth’s Crust to Rebound

Recent research has found that the magnitude of ice melt is causing the Earth’s crust to move as a result of the weight lost. 

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In case you missed it, we lost about 28 trillion tons of ice between 1994 and 2017, and it is now melting at a rate of 1.2 trillion tons a year. 

That’s more than the weight of all living things on earth. Each year. In fact, it’s enough that the Earth’s crust is moving, both vertically and horizontally as a result. 

This is a phenomenon known as post-glacial or crustal rebound, where land masses free of the huge weight of ice sheets are pushed back up by the viscoelastic mantle that underlies them. 

These movements have been considered over glaciated areas in the past, but Sophie Coulson and her team at Harvard University computed and mapped post-glacial rebound’s more far-reaching effects. According to their results, ice melting from Greenland and Arctic glaciers caused the ground to shift horizontally across much of the Northern Hemisphere, up to 3cm per decade in Europe, Canada and the US.

Source: Coulson et al. (2021).

The color coding indicates vertical rather than horizontal motion, which you can see has been distinctly stronger around Greenland. Though the rate of vertical motion is quite low (~1 cm per decade), we are speaking of masses beyond human understanding; a tectonic plate’s weight is of the order of 40 sextillion kilograms. 

The fact that there has been enough ice melt to make the earth’s crust move should give us a better appreciation of how much ice we are losing due to climate change.

This article was written by Owen Mulhern. Cover photo by jesse orrico on Unsplash.

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