So much ice is melting that the earth's crust is in motion

So much ice is melting that the earth's crust is in motion
So much ice is melting that the earth's crust is in motion

Melting ice in Greenland and Antarctica contributes to the lateral sliding of the earth's crust, even in places more than 1000 kilometers away. Between 2003 and 2018, the melting of ice in Greenland and the Arctic glaciers led to horizontal land displacement over much of the Northern Hemisphere.

As the frozen burden of the continents dissipates, the earth is warping - not only in the immediate vicinity of glaciers, but also in distant places.

The loss of melting ice from landmasses such as Greenland and Antarctica causes slight distortion of the earth's crust, even at locations more than 1000 kilometers from the site of ice loss.

Melting ice is removing mass from the Earth's continents. Freeing itself from the weight, the ground, which was once covered with ice, rises upward. This vertical response has been studied well enough, but Sophie Coulson of Harvard University in Cambridge, Massachusetts and her colleagues wanted to analyze how the earth shifts horizontally.

(a) Predicted mean rates of crustal deformation caused by ice loss from the Greenland Ice Sheet over the period 2003-2018 (Smith et al., 2020). (b) Predicted crustal deformation rates in North America and Europe during the years of relatively high (2012) and low (2006) mass loss of the Greenland Ice Sheet. Annual spatial ice mass loss is determined based on the analysis of GRACE gravity data. Vertical movements are shown with a red-blue color scale, and tangential movements are shown as vectors with arrows. Tangential movements in the vicinity of Greenland are excluded to emphasize the far-field response.

They collected satellite data on ice loss in Greenland, Antarctica, mountain glaciers and ice caps and combined it with a model of how the earth's crust responds to mass changes.

Between 2003 and 2018, melting ice from Greenland and Arctic glaciers caused horizontal ground displacement in much of the Northern Hemisphere, with 0.3 millimeters per year in most of Canada and the United States. In some areas, even far from the melting ice, horizontal movement was greater than vertical.

Geophys. Res. Lett. (2021)

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