Greenland’s peripheral glaciers are retreating rapidly, with recent studies showing a significant acceleration in the 21st century. This highlights the urgent need to address climate change to mitigate its impact on sea levels.
Greenland’s thousands of peripheral glaciers have entered a new and widespread state of rapid retreat, a study involving
The team extended records further back in time by leveraging clues hidden within the landscape. When glaciers grow larger and then retreat, they leave behind a terminal moraine — sediment transported and deposited by a glacier, often in the form of a long ridge. Locating these moraines enabled the researchers to map older glacier extents before pilots took their first flyover photos in the early 1930s. Altogether, this one-of-a-kind data documents changes in the lengths of more than 1,000 of the country’s glaciers from 1890 to 2022. “It’s quite extraordinary that we can now provide long-term records for hundreds of glaciers, finally giving us an opportunity to document Greenland-wide glacier response to climate change over more than a century,” says senior author Yarrow Axford, William Deering Professor of Geological Sciences in Northwestern’s Weinberg College of Arts and Sciences. Using the late 20th-century imagery as a baseline, the team calculated the percentage of length that glaciers have lost over the past 20 years. They found that, on average, glaciers in south Greenland lost 18% of their lengths, while glaciers in other regions lost between 5-10% of their lengths over the past 20 years. The only major possible exception are glaciers in northeast Greenland, where recent increases in snowfall might be slowing retreat. Peripheral glaciers represent only 4% of Greenland’s total ice-covered area but contribute 14% of the island’s current ice loss. “These glaciers, given their comparably smaller size, are the real canaries in the coal mine — they respond very quickly to Arctic warming,” Briner says. “Most projections of future sea level rise demonstrate that humanity still controls the knob. Fast action can stabilize temperature and sea level change after some in-the-pipeline change plays out.”Findings: Significant Glacial Length Loss
Reference: “Greenland-wide accelerated retreat of peripheral glaciers in the twenty-first century” by L. J. Larocca, M. Twining–Ward, Y. Axford, A. D. Schweinsberg, S. H. Larsen, A. Westergaard–Nielsen, G. Luetzenburg, J. P. Briner, K. K. Kjeldsen and A. A. Bjørk, 9 November 2023, Nature Climate Change.
DOI: 10.1038/s41558-023-01855-6
Avriel Schweinsberg, who received her PhD from UB in 2018, is also a co-author on the study.
The study was supported by the National Science Foundation’s (NSF) Geography and Spatial Sciences Program, NSF Polar Programs, the University Corporation for Atmospheric Research’s Cooperative Programs for the Advancement of Earth System Science, and the Villum Foundation.