Science & Technology

Melting polar ice that moves the earth itself, not just the surface of the sea

The melting of polar ice not only changes the level of our oceans, but also the earth itself. The newly created PhD Sophie Coulson and her colleagues explained in a recent treatise in Geophysical Research Letters that melting ice in Greenland, Antarctica and the Arctic Archipelago distorts the crust beneath these land masses. .. This impact can measure hundreds of miles, and in some cases thousands of miles. To that place.

“Scientists have done a lot of work right under ice beds and glaciers,” said Coulson, who worked in the Department of Earth and Planetary Sciences and received a PhD from the Graduate School of Arts and Sciences in May. “So they knew it defined the area where glaciers exist, but they were unaware that it was global.”

By analyzing satellite data on Melt from 2003 to 2018 and studying changes in the Earth’s crust, Coulson and her colleagues were able to measure the horizontal movement of the crust. Their study, highlighted in Nature, found that in some places the crust was moving more horizontally than it was lifted. In addition to its amazing range of reach, Nature Brief pointed out that this study provides a potentially new way to monitor changes in modern ice mass.

To understand how melting ice affects what lies beneath it, Coulson suggested imagining the system on a small scale. Push down on the board and the water below will move down. When you pick it up, you can see that the water moves vertically and fills the space. “

These movements affect continuous melting. “For example, in some parts of Antarctica, crustal bounces can change the slope of the bedrock beneath the ice sheet, which can affect ice dynamics,” Frank’s Jerry Mitrovica study. Coulson, who worked in the room, said. B. Baird Junior Science Professor.

The current melting is only the latest movements that researchers are observing. “The Arctic Circle is an interesting region, because there are not only modern ice sheets, but also permanent signals from the last glacial period,” Coulson explained. The ice sheet covered what is now Northern Europe and Scandinavia during the Pleistocene era. This ice age began about 2.6 million years ago and lasted about 11,000 years ago. “The Earth is actually still bouncing off the melting of its ice.”

“On modern timescales, we think of the Earth as a rubber band-like elastic structure, but on thousands of years of timescales, the Earth acts like a very slow-moving fluid,” Coulson said. Explained how these new effects overlap with the old reverberation. “The ice age process takes so long to run that we can still see the results today.”

The impact of this move is widespread. “Understanding all the factors that cause crustal movement is very important for various problems in earth science. For example, accurate observation of crustal movements and seismic activity is generated by the loss of modern ice sheets. We need to be able to separate this movement that has been done, “she said.

Coalson continues his research as a postdoc, director of the Los Alamos National Laboratory in New Mexico, as part of a climate group working on future predictions of ice sheets and ocean dynamics.

Glenn Antony Milne, a professor of global environmental science at the University of Ottawa, explained that understanding the extent of this movement would reveal all research on the planet’s crust. “Sophie’s research is important because it was the first to show that recent mass losses of ice sheets and glaciers cause 3D motion of the Earth. [solid] A surface that is larger and more spatially expansive than previously identified, “he said. “You can also look for this signal in regional and large global navigation satellite system datasets to, in principle, improve constraints on ice mass variation and / or distribution of solid Earth’s structure.”

Melting polar ice that moves the earth itself, not just the surface of the sea Melting polar ice that moves the earth itself, not just the surface of the sea

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