The mass loss of the Greenlandic ice sheet accounts for more than a quarter of global sea level rise. Scientists anxiously observe the increasing impact of climate change on the entire ice sheet.

Greenland’s ice sheet is the second largest mass of ice after the ice sheet of Antarctica. More than 3 km in thickness, it covers almost 82% of the world’s largest island. Credit: Michael Wenger
Greenland’s ice sheet is the second largest mass of ice after the ice sheet of Antarctica. More than 3 km in thickness, it covers almost 82% of the world’s largest island. Credit: Michael Wenger

An ice sheet loses ice by an increase of flow speed of its glaciers which in turn will release more ice into the oceans than are formed in the growth zones. On the other hand, in summer most ice streams melt on the top to such an extent that lakes and rivers are formed and release melt water into the ocean as well. The impact of a warming ocean on these factors is currently assessed by scientists from eight German universities and research centers in the new GROCE project, funded by the German Ministry for Education and Research (BMBF) with 3.5 million Euros and coordinated by the AWI.

Glaciers with a floating tongue are found mainly in the North of Greenland. They lose their mass mainly from above and below. ON the surface, ice melts due to warming air temperatures while on the lower side, the warming oceans affect the glacier bottoms. Graphics: Martin Künsting/Alfred-Wegener-Institut CC-BY 4.0
Glaciers with a floating tongue are found mainly in the North of Greenland. They lose their mass mainly from above and below. ON the surface, ice melts due to warming air temperatures while on the lower side, the warming oceans affect the glacier bottoms. Graphics: Martin Künsting/Alfred-Wegener-Institut CC-BY 4.0

„Together, we have set the goal to understand the complex relationships between ice sheet, earth crust, atmosphere, and ocean. The key to answering our questions relies on the integration of all the excellent competences of observations and modelling connected for the first time within a research group,” says project leader Prof. Dr. Torsten Kanzow, oceanographer at the AWI. To this end, oceanographers, glaciologists and geodesics will conduct coordinated air-, sea-, and land campaigns in the Northeast of Greenland and then analyze their measurements with appropriate computer models. “The results should enable us to integrate the interaction between ice sheet and ocean in a more realistic way into our climate models to better predict changes in sea level and ocean circulation,” says AWI oceanographer Dr. Ursula Schauer.

Nos hip has ever reached this site before: The Polarstern in front of the 79°-North-glacier in the Northeast of Greenland. Credit: Nat Wilson
Nos hip has ever reached this site before: The Polarstern in front of the 79°-North-glacier in the Northeast of Greenland. Credit: Nat Wilson

A core area of the campaign will be the 79°-North-Glacier in the northeast corner of Greenland. It is special amongst all glaciers in Greenland as it had been classified as stable unlike the glaciers along the west and the southern coast of Greenland. However, signs are increasing that this glacier starts to thin out, too. Nonetheless, it still has a 80 km-long ice tongue floating on the surface of the ocean. “For glaciologists like us, it will be extremely fascinating to conduct our research efforts exactly at the point where the glacier loses contact to the sea floor and starts floating. This so-called grounding line plays a crucial role in our ice models because here, the warming ocean as well as the flow characteristics and other physical properties affect the glacier,” explains AWI-glaciologist Dr. Angelika Humbert. “Until now, those two huge systems ice sheet and ocean had been analyzed independently. In the GROCE project glaciologists, geodesics, and oceanographers cooperate to examine the intersection between ice and water together and eventually to find changes which are relevant for our climate and sea level rise. This aspect in itself makes the whole project already very appealing for us,” adds Dr. Ursula Schauer

Source: AWI