Meltdown in Greenland: Glaciers Losing Ground Twice as Fast

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Greenland’s Peripheral Glaciers in Rapid Retreat: 21st Century Loss Rate Doubles Compared to 20th Century

A recent study, involving researchers from the University at Buffalo among others, has unveiled a troubling trend in Greenland. The peripheral glaciers of Greenland, according to satellite and historical aerial data, are retreating at an alarming pace. Comparing the retreat rates of the 21st century to the 20th century, it becomes evident that the rate has doubled, emphasizing the swift response of these glaciers to climate change and the consequential threat of rising sea levels.

Greenland’s numerous peripheral glaciers are now undergoing a widespread and swift retreat, as illuminated by a study in collaboration with the University at Buffalo (UB).

By combining satellite imagery with historical aerial photographs of Greenland’s coastline, a research team led by Northwestern University and the University of Copenhagen has determined that the retreat of these glaciers during the 21st century is occurring at a pace twice as fast as it did in the 20th century.

Jason Briner, a co-author of the study and a professor of geology in the College of Arts and Sciences, emphasizes the significance of these findings: “The results add to growing documentation that glaciers in the Arctic are responding quickly to rising temperatures due to human-induced climate change. This is concerning because their meltwater contributes to global sea level rise.”

The Role of Historical Aerial Photographs

Before Earth-observing satellites were launched in the 1970s, researchers lacked comprehensive insights into how temperature variations affected Greenland’s glaciers. In fact, detailed observational records were thought to be nonexistent. However, a pivotal discovery was made approximately 15 years ago when forgotten aerial photographs of Greenland’s coastline were unearthed in a castle outside Copenhagen.

Laura Larocca, the study’s first author, explains, “Starting in the 1930s, Danish pilots, donned in polar bear-fur suits, embarked on aerial mapping expeditions of Greenland, amassing over 200,000 photos of the island’s coastline. Unintentionally, they also captured the state of Greenland’s peripheral glaciers.”

These images enabled Anders Bjørk, the senior author of the study and an assistant professor at the University of Copenhagen, to begin reconstructing the glaciers’ historical changes.

In previous studies, Bjørk and his collaborators digitized and analyzed photos to examine 361 glaciers in various regions of Greenland. In this new study, the Northwestern-led team expanded on this research by adding records for 821 more glaciers across different regions and extending Bjørk’s records to the present day.

A Comprehensive Glacial Chronicle

As part of this endeavor, the team digitized thousands of paper-copy aerial photographs taken from open-cockpit planes and collected imagery from multiple satellites. The researchers also corrected for terrain distortion and used geo-referencing techniques to accurately position the photos on Earth.

The team further extended the records by uncovering clues within the landscape. When glaciers advance and then recede, they leave behind terminal moraines—sediment transported and deposited by the glacier, often in the form of a long ridge. Identifying these moraines allowed the researchers to map the extents of older glaciers before the initial flyover photos were taken in the early 1930s.

In total, this unique dataset traces changes in the lengths of over 1,000 of Greenland’s glaciers from 1890 to 2022.

Significant Loss in Glacial Length

Using late 20th-century imagery as a baseline, the team calculated the percentage of length that glaciers have lost over the past two decades. They found that, on average, glaciers in southern Greenland have lost 18% of their lengths, while glaciers in other regions have lost between 5-10% of their lengths during the same period. Notably, glaciers in northeast Greenland may be an exception due to recent increases in snowfall potentially slowing their retreat.

Although peripheral glaciers account for just 4% of Greenland’s total ice-covered area, they contribute 14% of the island’s current ice loss. As Jason Briner emphasizes, “These glaciers, despite their relatively smaller size, are early indicators of Arctic warming, responding rapidly. Most projections of future sea level rise indicate that humanity still has the ability to mitigate the consequences with swift action to stabilize temperature and sea level changes.”

For more information on this research, you can refer to the following sources:

• “Greenland Glaciers Melting 5x Faster Than 20 Years Ago”
• “Greenland’s Glacier Retreat Doubled in 20 Years”

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, published on November 9, 2023, in the journal Nature Climate Change. DOI: 10.1038/s41558-023-01855-6.

Additionally, Avriel Schweinsberg, a co-author on the study, received her PhD from UB in 2018. The study received support from 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.

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More about Glacial Retreat

• [Greenland Glaciers Melting 5x Faster Than 20 Years Ago](insert link here)
• [Greenland’s Glacier Retreat Doubled in 20 Years](insert link here)
• [Reference: “Greenland-wide accelerated retreat of peripheral glaciers in the twenty-first century” – Nature Climate Change](insert link here)