Melting polar ice caps move Earth from within, triggering movement

As the leaders of the free world gather in Glasgow, Scotland this month, they will have a great challenge to ensure the survival of the planet as global warming and climate change trigger extreme events across the world. One of these events is observed at the top and bottom of the planet, where ice caps deform the earth’s crust.

A new study shows how the continued melting of the polar ice caps causes a subtle change in the shape of the planet thousands of miles away from the melting of the ice caps. As the ice caps melt, the overall pressure on the surface is reduced, forcing it to move.

The new study published in Geophysical Research Letters states that as ice caps and glaciers melt and water is redistributed across the world’s oceans, the earth’s crust is deformed, generating a complex pattern of 3D motions on the earth’s surface. “This 3D surface motion averages several tenths of a millimeter per year, and it varies considerably from year to year,” the researchers said in the article.


The researchers analyzed satellite data from melting ice from 2003 to 2018 and studied the corresponding changes in the earth’s crust to measure the horizontal displacement of the crust. They observed that while in some places the crust moved slowly, it was more of a horizontal movement than a vertical uplift. Researchers believe that this movement and continued melting of the ice caps alters the slope of the bedrock below.

“The Arctic is an interesting region because, in addition to modern ice caps, we also have a lasting signal from the last ice age. The Earth is actually still bouncing after the ice melts. On recent timescales, we think of the Earth as an elastic structure, like a rubber band, whereas on timescales of thousands of years, the Earth rather acts like a very slow fluid, ”said Sophie Coulson. , postdoctoral researcher at Los Alamos. The New Mexico National Laboratory that conducted the research at Harvard University told the Harvard Gazette.

An image of the layers of the Earth. (Photo: Getty)

The article’s researchers said that they use satellite-derived constraints on the early 21st century ice balance of Greenland and Antarctica ice caps, and a global database of mountain glaciers and ice caps, to predict how the crust has changed. has been distorted over the past two decades.

The crust forms the outermost shell on Earth with a depth of up to 40 kilometers below the surface. According to the National Geographic Society, the crust is made up of solid rocks and minerals and the layers of the Earth constantly interact with each other, and the crust and the upper mantle are part of a single geological unit called the lithosphere. .


Researchers analyzed that ice mass loss has increased dramatically since the turn of the century with ground ice loss from the Antarctic ice sheet, Greenland ice sheet and mountain glaciers increasing by 60%. in the 2010s compared to the previous decade.

“The impacts of ice mass loss on the Earth system are global in scope,” the researchers said, adding that this results in significant geographic variability on a global scale in sea level change.

Studying this motion is not only essential for accurately predicting tectonic motions and earthquakes. The researchers said that in order to accurately observe tectonic movements and seismic activity, we must be able to separate this movement generated by the mass loss of modern ice.

“Scientists have done a lot of work directly under ice caps and glaciers. So they knew that would define the region where the glaciers are, but they didn’t realize it was on a global scale, ”Colson told the Harvard Gazette.

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