Glacier melt is causing Earth’s crust to warp slightly, say scientists

As ice sheets and glaciers melt across the globe, the Earth’s crust is liberated from the overlying weight and lifts up, say scientists

The melting of ice from glaciers and landmasses such as Greenland and Antarctica is causing the Earth’s crust to warp slightly, a new study suggests.

As ice sheets and glaciers melt across the globe and water is redistributed to global oceans, the Earth’s crust is liberated from the overlying weight and lifts up, said the research published in the journal Geophysical Research Letters last week.

This melting could generate a complex pattern of three-dimensional (3D) motions at the Earth’s surface, even in places over 1,000 kilometres away from the ice loss, according to the scientists behind the study, including Sophie Coulson from Harvard University in the US.

“This 3D surface motion is on average several tenths of a millimetRE per year, and it varies significantly year to year,” the study noted.

In the research, scientists used satellite-derived data on early 21st century ice loss from Greenland, Antarctica, mountain glaciers and ice caps, to predict how the Earth’s crust deforms with changes in its mass.

Between 2003 and 2018, ice melting from Greenland and the Arctic glaciers have “caused the ground to shift horizontally” across much of the Northern Hemisphere, changing by as much as 0.3 millimetres (mm) a year in large parts of Canada and the US, said researchers.

“We show that, rather than only being localised to regions of ice loss, melting of the Greenland Ice Sheet and Arctic glaciers has caused significant horizontal and vertical deformation of the crust that extends over much of the Northern Hemisphere,” the scientists wrote in the study.

The study predicted a crust deformation of 0.05–0.3 mm per year in most parts of Canada and the US, with a deformation of 0.05–0.2 mm per year in Europe, including parts of Fennoscandia, which constitutes Finland, Norway and Sweden.

Climate researchers call for future work to further assess crustal warping due to ice melting to improve both horizontal and vertical measurements made by navigational satellite systems.