One of the 200,000 images gathered by Danish pilots (from open-cockpit planes) of Greenlands coastline. Credit: Danish National Archives
Sped up Retreat in the 21st Century
Although glaciers in Greenland have experienced retreat throughout the last century, the rate of their retreat has actually rapidly accelerated over the last 20 years. According to the multiyear collective effort between the United States and Denmark, the rate of glacial retreat throughout the 21st century is two times as quick as retreat during the 20th century. And, regardless of the variety of climates and topographical attributes across Greenland, the findings are ubiquitous, even among Earths northernmost glaciers.
The findings highlight the areas level of sensitivity to increasing temperature levels due to human-caused environment modification.
The research study was just recently released in the journal Nature Climate Change.
An aerial image of Greenlands shoreline from the archives. To build how Greenlands peripheral glaciers have actually altered over the years, researchers digitized thousands of paper-copy aerial pictures drawn from open-cockpit aircrafts and gathered images from several satellites. Credit: Laura Larocca
” Our research study puts the current retreat of peripheral glaciers throughout Greenlands varied climate zones into a century-long point of view and recommends that their rate of retreat in the 21st century is mainly extraordinary on a century timescale,” stated Laura Larocca, the research studys first author. “The just major possible exception are glaciers in northeast Greenland, where it looks like recent boosts in snowfall may be slowing retreat.”
Value of Slowing Global Warming
The research study discovers that climate modification discusses the accelerated glacier retreat and that glaciers throughout Greenland respond rapidly to altering temperatures. This highlights the significance of slowing international warming.
” Our activities over the next couple of decades will greatly affect these glaciers. Every bit of temperature boost actually matters,” Larocca said.
An aerial photo of Greenlands coastline from the Danish National Archives. To construct how Greenlands peripheral glaciers have actually changed over the years, scientists digitized countless paper-copy aerial photographs taken from open-cockpit aircrafts and collected imagery from multiple satellites. Credit: Laura Larocca
Distinct Data Collection Methodology
” This work is based upon huge analyses of satellite imagery and digitization of countless historic aerial photos– some taken throughout early mapping explorations of Greenland from open-cockpit aircrafts,” said Northwesterns Yarrow Axford, a senior author on the study. “Those old images extend the dataset back prior to the satellite period, when widespread observations of the cryosphere are uncommon. Its quite amazing that we can now offer long-lasting records for hundreds of glaciers, lastly providing us an opportunity to record Greenland-wide glacier response to environment modification over more than a century.”
When the research study started, Larocca was a Ph.D. prospect in Axfords laboratory. She will join Arizona State Universitys School of Ocean Futures as an assistant teacher in January 2024.
An aerial image of Greenlands coastline from the Danish National Archives. To construct how Greenlands peripheral glaciers have actually changed over the years, scientists digitized thousands of paper-copy aerial photographs drawn from open-cockpit aircrafts and gathered images from several satellites. Credit: Laura Larocca
Concentrate On Peripheral Glaciers
While climate changes results on Greenland are well studied, most researchers focus on the Greenland Ice Sheet, which covers approximately 80% of the country. Variations in Greenlands peripheral glaciers– the smaller ice masses distinct from the ice sheet that dot the countrys coastline– are commonly undocumented, in part due to an absence of observational information.
Prior to the launch of Earth-observing satellites in the 1970s, researchers did not have a complete understanding of how temperature changes affected Greenlands glaciers. Now housed within the Danish National Archives, the images made it possible for study senior author Anders Bjørk, an assistant professor at the University of Copenhagen, to begin constructing the glaciers history.
” Starting in the 1930s, Danish pilots dressed in polar bear-fur fits set out on aerial mapping projects of Greenland and wound up collecting over 200,000 pictures of the islands coastline,” Larocca stated. “They likewise inadvertently recorded the state of Greenlands peripheral glaciers.”
Photo of Greenland, taken during a field research trip by Northwestern University scientists. Credit: Laura Larocca
Comprehensive Effort in Data Processing
In previous studies, Bjørk and his collaborators digitized and analyzed pictures to study 361 glaciers in the southeast, northwest, and northeast areas of Greenland. In the brand-new study, Larocca, Axford, and their group included records for 821 more glaciers in the south, north, and west areas and extended Bjørks records to the present day.
As a part of this effort, the team digitized thousands of paper-copy aerial photos taken from open-cockpit airplanes and gathered imagery from multiple satellites. The scientists also removed surface distortion and used geo-referencing strategies to position the images at the right locations on Earth.
” There actually arent any automated procedures to digitize all these images,” said Larocca, who started the project in 2018. “A job like this takes a lot of people and a lot of manual work to digitize and scan all these analog air photos. We had to do a lot of preprocessing work before making our measurements.”
Picture of contemporary Greenland, taken during a field research study journey by Northwestern University scientists. Credit: Laura Larocca
Historical Clues and Recent Findings
Larocca, Axford, and their group likewise extended records even more back in time by leveraging hints concealed within the landscape. When glaciers grow larger and after that retreat, they leave a terminal moraine (sediment carried and deposited by a glacier, often in the type of a long ridge). Locating these moraines enabled the scientists to map older glacier extents before pilots took their very first flyover photos in the early 1930s.
Using the late 20th-century images as a baseline, Larocca, Axford, and their team also computed the portion of length that glaciers have actually lost over the previous 20 years. They found that, typically, glaciers in south Greenland lost 18% of their lengths, while glaciers in other regions lost between 5-10% of their lengths over the previous 20 years.
Broader Implications of Melting Glaciers
As global temperature levels increase, it has ended up being more vital than ever to much better understand how these melting glaciers will affect rising water level and trusted sources of fresh water.
” Peripheral glaciers only represent about 4% of Greenlands total ice-covered area, however they contribute 14% of the islands existing ice loss– a disproportionately big portion,” Larocca stated. “If you look globally at all glaciers that are distinct from the Greenland and Antarctic Ice Sheet, they have actually contributed approximately 21% of observed sea level rise over the last 2 years.
For more on this research, see Greenland Glaciers Melting 5x Faster Than 20 Years Ago.
Recommendation: “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.
The research study was supported by the National Science Foundations (NSF) Geography and Spatial Sciences Program, NSF Polar Programs, the University Corporation for Atmospheric Researchs Cooperative Programs for the Advancement of Earth System Science and the Villum Foundation.
Brand-new study documents how Greenlands peripheral glaciers have changed from 1890 to 2022
Using satellite images and a special archive of historic aerial pictures, scientists put together the most complete image of Greenlands removed glaciers to date
Researchers discovered glacier retreat accelerated dramatically in the 21st century
Glaciers in Greenland have experienced retreat throughout the last century, the rate of their retreat has actually rapidly sped up over the last two years. To build how Greenlands peripheral glaciers have changed over the years, scientists digitized thousands of paper-copy aerial pictures taken from open-cockpit aircrafts and gathered imagery from multiple satellites. To build how Greenlands peripheral glaciers have altered over the years, scientists digitized thousands of paper-copy aerial photos taken from open-cockpit aircrafts and collected imagery from multiple satellites. Its rather remarkable that we can now provide long-lasting records for hundreds of glaciers, finally offering us a chance to record Greenland-wide glacier response to environment change over more than a century.”
When glaciers grow larger and then retreat, they leave behind a terminal moraine (sediment transferred and deposited by a glacier, typically in the form of a long ridge).
A collective research study has actually found that Greenlands peripheral glaciers are pulling away at an extraordinary rate, with the retreat in the 21st century being twice as quick as in the 20th century. This rapid modification, linked to climate change, was exposed through a combination of satellite and historic aerial imagery.
The new findings are ubiquitous, even among Earths northernmost glaciers.
One of the 200,000 images gathered by Danish pilots (from open-cockpit planes) of Greenlands coastline. Credit: Danish National Archives
Widespread and Rapid Retreat of Greenlands Glaciers
Greenlands thousands of peripheral glaciers have actually gotten in a widespread and brand-new state of fast retreat, a Northwestern University and University of Copenhagen study has actually discovered.
To piece together the magnitude of glacier retreat, the research team integrated satellite images with historical aerial photos of Greenlands shoreline, which is dotted with countless glaciers that are different from the islands massive central ice sheet. With these distinctive data, the researchers documented modifications in the lengths of more than 1,000 of the countrys glaciers over the previous 130 years.
