By Penelope Gardner
Medill Reports, Dec. 13, 2023
An expansive glacier sits on the southeastern side of Greenland, leading from the Greenland ice sheet into the Sermilik Fjord. Almost four miles wide, its length typically ebbs and flows in size each season, but this past summer, Helheim Glacier lost one and a half miles (2.4 kilometers) of ice in a massive calving event.
Sierra Melton, a Ph.D. candidate at Pennsylvania State University, is tracking the accelerating melt of the Helheim Glacier due to global warming. Typically she relies on satellite photos to provide insight into changes in the glacier’s dimensions, but she visited the glacier in July in the days following the calving.
“2.4 kilometers for just one retreat in just one morning,” Melton said. “I have never seen it of this scale before.”
Glaciers grounded on land but losing ice into the ocean add to sea level rise, which impacts island and coastal communities globally. Melton and her advisors Richard Alley, Sridhar Anandakrishnan and Byron Parizek have been studying Helheim Glacier for the past several years to target the pace of melting and sea level rise. This research can also be applied to Antarctica’s ice sheet.
“Understanding how an ice shelf or ice tongue breaks off, and then how that remaining ice cliff behaves is something that, if a good representation of that can be put into the sea level or the ice sheet models, that would help with projections of sea level rise,” Melton said.
Melton and Anandakrishnan went to Greenland in July to place seismic sensors on Helheim to gather more information about what happens before the ice breaks off or calving occurs.
“It’s a fantastic laboratory to see what might happen to Antarctica in the future,” Alley said. Scientists know Antarctica’s average temperatures are rising faster than in other areas of Earth, in a dramatic feedback loop between warming, ice melt and sea level rise.
They arrived on July 4, and sometime between their arrival in Greenland and when they approached the glacier by helicopter on July 5, the 1.5 miles of ice detached from the glacier.
“In lots of cases, an ice shelf breaking off would be very worrisome,” Melton said. “Helheim has done similar things before. I’ve been looking at it in satellite imagery for many years, and it’s common for it to advance into the fjord during the winter, and then a retreat similar to this happens.”
Melton speculated that this massive retreat was due to a greater advance into the fjord than what typically occurs. Global warming due to climate change is a contributing factor.
Because Helheim is so similar to the glaciers at the termination of the Antarctic ice sheet, this is a big learning experience for researchers.
“If this happens in Antarctica, it really could drive a lot of sea level rise,” Alley said.
According to U.N. reports, seas will rise between three and 12 inches by 2030. This will affect equatorial regions and coastal communities the most, with increased flooding and higher tides.
And the levels could accelerate
Education about climate change is important. Children at a local school in Greenland crafted drawings of icebergs that Melton and her colleagues placed on icebergs in the fjord along with GPS transmitters so that students could track and “race” the icebergs that had their drawings, creating an engaging way for children to learn about global warming.
Melton reported her findings at the annual Comer Climate Conference in Southern Wisconsin this fall. The conference draws interdisciplinary scientists from across the world who are piecing together climate impacts that show the urgency of addressing climate change.
Photo at top: Helheim Glacier leads from the Greenland ice sheet into the Sermilik Fjord. (Sierra Melton)
