As Greenland melts and rises | Polarjournal
With the melting of Greenland’s ice sheets, particularly the glaciers (as seen here at Ilulissat), the island’s bedrock is rising at a particularly high rate. Image: Julia Hager

Within ten years, the ground in Greenland has risen by 20 centimetres in certain places. This is due to the post-glacial rebound caused by the rapid melting of the ice masses covering Greenland. With ground levels rising faster than sea levels, Greenland won’t have to worry about flooding. On the other hand, it will face other challenges.

When a large mass of ice covers a land mass, it compresses the latter under its weight. If the ice melts, the ground, now free of the ice mass, rises. This is post-glacial rebound, a phenomenon also known as isostatic rebound. In itself, the fact that Greenland is rising is nothing special. Since the last Ice Age, which ended about 12 000 years ago, the earth has continued to rise in Greenland and elsewhere.

But the problem here is the speed with which the land mass rises in Greenland. Between 2013 and 2023, the ground rose by 20 centimetres, the equivalent of two metres in a century. These are the findings of a study published in Geophysical Research Letters on January 13. The reason for this uplift is linked to global warming, which is melting ice caps and glaciers at a fast pace. “The land uplift we observe in Greenland these years cannot be solely explained by the natural post-ice age development. Greenland is rising significantly more.”, says Shfaqat Abbas Khan, professor at DTU Space and co-author of the study, in a press release published on February 2 on the DTU Space website.

To arrive at these results, the researchers analyzed data collected by GNET, a network of 61 measuring stations located along the coast of Greenland. The network is owned by the Danish Ministry of Climate, Energy and Utilities’ Data Supply and Infrastructure Agency. The network is operated in cooperation with the DTU.

The GNET infrastructure measures ice melt and land uplift, making it possible to detect bedrock movements down to the millimetre. Map: GNSS – Grønland

In the case of Greenland, the situation is particularly obvious on the coast line. Glaciers are melting faster than the ice cap. This is particularly true of the Sermeq Kujalleq glacier, near the town of Ilulissat, and the Kangerlussuaq glacier in southeast Greenland. The latter has lost a significant mass of ice, retreating 10 km since the beginning of the 20th century.

As the world fears a rise in sea levels due to the melting of the cryosphere, which includes the ice covering Greenland, the island is unlikely to have to worry about flooding. In fact, its soil is rising faster than sea level. However, the island will have to face other kind of problems.

With the emergence of new lands, geographical and maritime maps will have to be revised. Infrastructure and construction projects will also have to take account of this rebound effect: “If, for example, a new port needs to be build, the gradient of the terrain will have to be taken into account,” as Danjal Longfors Berg, PhD student at DTU Space and lead author of the study, recently told the Danish science news outlet Videnskab.dk. “Because it doesn’t help that a fishing boat can no longer dock because the wharf has risen two meters in the last 100 years.”

Link to study: D. Berg, V. R. Barletta, J. Hassan, E. Y. H. Lippert, W. Colgan, M. Bevis, R. Steffen, S. A. Khan, Vertical Land Motion Due To Present-Day Ice Loss From Greenland’s and Canada’s Peripheral Glaciers, Geophysical Research Letters, 2024, https://doi.org/10.1029/2023GL104851

Mirjana Binggeli, PolarJournal

More on the subject

Print Friendly, PDF & Email
error: Content is protected !!
Share This