Will the sea rise by 20 cm or 3 metres by 2100? This is obviously an interesting question to answer. Predicting the sea level in 75 years requires precise calculations and correct models of the melting of the ice from, e.g., Greenland. To do so, researchers need valid data—and photos, too. All of this can be obtained by space technology.
For almost 20 years, this is exactly what Professor Shfaqat Abbas Khan from DTU Space has used in connection with the numerous research articles published by him and his colleagues on the melting of the Greenland ice sheet. On several occasions, the researchers have gained new knowledge about the extent of ice melting, the speed at which it occurs, the acceleration of the melting, and the changes in the landscape that it causes.
How much of this knowledge would have seen the light of day without space technology?
"Nothing," is the short answer from Shfaqat Abbas Khan.
"We are deeply dependent on space technology to be able to observe changes in ice, water, and land," the professor elaborates.
GPS monitoring of mountains
In 2023, Shfaqat Abbas Khan was appointed to head up the Center for Ice-Sheet and Sea-Level Predictions (CISP), which—with a grant of DKK 37 million from the Novo Nordisk Foundation—brings together researchers from the Geological Survey of Denmark and Greenland, the University of Copenhagen, and the American Dartmouth College.
Until 2029, the researchers will use many different space observations to study the melting of ice, not only in Greenland, but across the globe, i.e. also the melting from both poles and mountain glaciers. With this knowledge, the researchers will develop new models that predict sea level rise.
A core technology in Shfaqat Abbas Khan and his colleagues' research into the melting of the Greenland ice sheet has for many years been the GNET network, which consists of 61 GPS stations located along Greenland's coasts. GNET is owned by the Danish Agency for Climate Data under the Danish Ministry of Climate, Energy and Utilities.
The GPS stations use signals from GPS satellites, and the stations' location on the Greenlandic mountains makes it possible to monitor changes in the height of the mountains with a precision of as little as 1/10 millimetre.
This has led to studies that have shown how much the Greenlandic mountains rise, which is interesting to follow, because when the ice sheet on top melts, the pressure on the mountains is relieved, and they thus rise. At the beginning of 2024, new results showed that—in some places—there was a rise of up to 20 cm over the ten-year period 2013-2023.
