In the far north-east of Greenland, ground-based gauges and airborne radars show how much ice the 79°N glacier is losing. According to measurements made by the Alfred Wegener Institute, the thickness of the glacier has decreased by more than 160 meters since 1998. Warm ocean water flowing beneath the glacier tongue melts the ice below.

High temperatures cause lakes to form on the surface, and the water from these lakes flows into the ocean through huge channels in the ice. According to a research team report, one of the channels reached an altitude of 500 meters, while the ice above it was only 190 meters deep. cryosphere.

A rural camp in northeastern Greenland was one of the bases where independent measuring devices with advanced radar technology were deployed on a helicopter in the hard-to-reach part of the 79° north glacier. Polar drone measurement flights and satellite data from the Alfred Wegener Institute, Helmholtz Center for Polar and Marine Research (AWI) were also included in the scientific study now published.

This study examines how global warming affects the stability of a floating ice tongue. This is of great importance for the remaining ice shelves in Greenland and Antarctica; because ice shelf instability often causes ice to flow faster, resulting in further sea level rise.

The first author of the paper is AWI glaciologist Dr. “Since 2016, we have been using autonomous vehicles to make radar measurements on the 79° North Glacier; from these measurements we can determine the rate of melting and thinning,” says Ole Zeising. “We also used aircraft radar data from 1998, 2018 and 2021, which showed changes in ice thickness. We were able to measure that the 79° north glacier has changed significantly in recent years due to the impact of global warming.”

The study shows how the combination of warm ocean flow and atmospheric warming affects the floating ice tongue of the 79°N glacier in northeast Greenland. A group of AWI oceanographers recently published a model study on this topic. The unique set of observational data presented shows that extremely high melt rates occur over a wide area near the transition to the ice sheet.

Additionally, large channels form on the underside of the landside ice, possibly because water from large lakes flows through the glacier ice. Both processes have led to strong thinning of the glacier in recent years.

Due to its extraordinary melting rate, the ice at the tongue of the floating glacier has thinned by 32% since 1998, especially from where the ice contacts the ocean. In addition, a 500-meter-high channel was created at the bottom of the ice, extending towards the land.

Researchers explain these changes by warm ocean currents in the space beneath the floating tongue and the flow of meltwater on the surface as a result of atmospheric heating. An unexpected discovery was that the melting rate has decreased since 2018. One possible reason for this is cold ocean currents.

Professor Dr. who took part in the research. “The fact that this system reacts in such a short time is impressive for systems that are essentially motionless, such as glaciers,” says Angelica Humbert.

“We expect this floating tongue of glacier to break up in the next few to decades,” explains the AWI glaciologist. “We started to study this process in detail to get maximum information about the course of the process. Although there were several similar breaks in the ice shelf, it was only later that we were able to collect data. As a scientific community, we are now in a better position to have established a really good database before the accident.” “We are in position.”