The melting of Earth’s polar ice distorts the planet’s crust.
This change in shape is subtle, but occurs hundreds of miles away from the ice sheet. Researchers may be able to monitor shifts and understand how to do so as part of their research. Climate change Affects the sea level.Understanding warpage is also important, as scientists need to be able to correct this seismic motion when measuring other types of geological processes, the study author wrote in the August issue of the journal. Geophysics Research Letter..
Scientists already knew that when the ice disappeared, the underlying crust would change. Imagine lifting your head off a memory foam pillow. When the weight of the head is lifted, the pillow gradually returns to its original position and continues to move after the bed is vacated. The same thing happens when glaciers recede. The underlying crust no longer weighs, but slowly returns. This is called isostatic rebound and is actually very slow. In some high latitudes, the ground is still bouncing from the receding ice sheet at the end of the Last Glacial Period.
But now, the polar regions are losing more and more ice due to climate change. From 2000 to 2010 Antarctica, Greenland and mountain glaciers increased by 60% between 1990 and 2000 compared to ice loss, according to a paper published in 2020. Cryosphere.. This melting affects the shape of the crust, much like ice was lost at the end of the ice age. However, most studies focus on changes in the crust beneath and around the ice sheet. Even when researchers study distant effects, they focus on vertical changes in the shape of the crust. However, the movement of the crust after the loss of ice is three-dimensional and also moves horizontally.
Sophie Coalson, a postdoctoral fellow at the Los Alamos National Laboratory in New Mexico, who studied while attending Harvard University, wanted to investigate the effects of ice loss in the 21st century in 3D on a global scale. Using satellite data collected between 2003 and 2018, she and her colleagues look for small movements in the crust and change those changes with the loss of ice in Antarctica, Greenland, and high-latitude glaciers. I compared it every year.
They found that the horizontal movement of the crust often outweighed the vertical movement (uplift). Movement was highly dependent on the amount of ice lost each year, but in both high and low loss years, most of North America averaged more horizontal movement than vertical movement. Horizontal creep, mostly northward, peaked in 2012 at a maximum of 0.017 inches (0.45 mm). In low-loss years, this movement averaged about 0.004 inches (0.1 mm) across the continent.
In the early 2000s, ice rapidly receded from the Antarctic Peninsula and West Antarctica, but East Antarctica acquired ice. This increase or decrease was eventually averaged in terms of the Earth’s crust, so most of the deformation was confined to a relatively small area of the South Pacific. The Northern Hemisphere was a different story. Ice loss from north latitude in the Northern Hemisphere was associated with an average of 0.015 inches (0.4 mm) of horizontal (mostly northward) movement each year. This included up to 0.01 inch (0.3 mm) movement in Canada and the United States, and up to 0.008 inch (0.2 mm) movement in Europe and Scandinavia.
These numbers may not seem important, but they are summed over time. And this distortion can affect how future ice loss unfolds.
“For example, in some parts of Antarctica, crustal bounces change the slope of the rock beneath the ice sheet, which can affect ice sheet dynamics,” Coleson said. Harvard Gazette.. The steeper the slope, the faster the ice will flow towards the sea.
Originally published in Live Science..
The disappearing ice distorts the earth’s crust
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