This is due to plate tectonics and movements in bedrock caused by the melting of large ice sheets above and the release of pressure on the subsurface. new paper published in Journal of Geophysical Research: Solid Earth. The pressure is easing both because large amounts of ice have melted in Greenland in recent years and because the bedrock is still affected by the huge masses of ice that have melted since the peak of the last ice age about 20,000 years ago. As a result, the entire island has shifted northwestward by about 2 cm per year over the past 20 years.
Horizontal land motion is observed by 58 GNET stations in Greenland. Image credit: Longfors Berg etc.., doi: 10.1029/2024JB030847.
“Overall this means Greenland is getting a little smaller, but that could change in the future due to the accelerating melting we're seeing now,” said Dr. Danyal Longfors Berg, a researcher at the Technical University of Denmark and NASA's Jet Propulsion Laboratory.
“The geophysical processes influencing the shape of Greenland are pulled in different directions.”
“The ice that has melted in recent decades has pushed Greenland outward and caused uplift, so the area has actually gotten larger over this period.”
“At the same time, we see movement in the opposite direction, where Greenland is rising and shrinking due to prehistoric changes in ice masses associated with the last ice age and its end.”
This is the first time that horizontal movements have been described in such detail.
“We have created a model that shows movements over a very long period of time, from about 26,000 years ago to the present,” said Dr Longfors Berg.
“At the same time, we have used very precise measurements from the last 20 years, which we use to analyze current movements.”
“This means we can now measure movements very accurately.”
The new measurements are based on data collected by 58 GNSS (GPS) stations located around Greenland.
These stations measure Greenland's general position, changes in rock height, and how the island is compressed and stretched.
“There have never been such precise measurements of how the situation in Greenland is changing before,” said Dr Longfors Berg.
“Greenland was thought to be primarily being stretched due to dynamics caused by melting ice in recent years.”
“But to our surprise, we also found large areas where Greenland is being pulled in or compressed by the movements.”
A new study provides useful information about what happens when climate change hits the Arctic at an accelerating rate, as it has in recent years.
“It is important to understand the movement of land,” said Dr. Longfors Berg.
“They are of course interesting for the geosciences. But they are also crucial for geodesy and navigation, since even fixed landmarks in Greenland are slowly shifting.”
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D. Longfors Berg etc.. 2025. Estimation and attribution of horizontal land motion measured by the Greenland GNSS network. JGR: Solid Earth 130(9):e2024JB030847; doi: 10.1029/2024JB030847
