A team of researchers, including an expert from Swansea University, has achieved a significant milestone by mapping the sub-glacial terrain beneath Antarctica’s most at-risk glacier. This groundbreaking study of Thwaites Glacier’s sub-glacial geology in West Antarctica has provided crucial knowledge about its vulnerability to climate change.
The research, led by the British Antarctic Survey (BAS) and involving Professor Bernd Kulessa from Swansea University’s geography department, has uncovered a scarcity of sedimentary rock beneath the glacier—an unexpected revelation that could impact its future movement towards the ocean over the next few decades.
Thwaites Glacier, an ice-ocean system roughly the size of Great Britain or the US state of Florida, is renowned for its rapid transformation. It stands as one of Antarctica’s fastest-changing regions.
The findings of the study, which resulted in a new geological map of the area published in the journal Science Advances, were made possible through extensive airborne surveys using radar-equipped aircraft capable of penetrating the ice and detecting the underlying rock formations. Additionally, gravity and magnetism sensors provided detailed insights into the subsurface layers situated thousands of meters below the glacier.
By integrating the data collected from these various sources, the researchers compiled a comprehensive 3D representation, highlighting distinct rock features and their distribution.
Dr. Tom Jordan, a geophysicist at the British Antarctic Survey who spearheaded the study, explained the significance of their findings: “Sediments allow faster flow, like sliding on mud. Now we have a map of where the slippery sediments are, we can better predict how the glacier will behave in the future as it retreats.”
The grounding zone of Thwaites Glacier, where it meets the seafloor, has already retreated by approximately 14 kilometers since the late 1990s. With a substantial portion of the ice sheet situated below sea level, this vulnerable region is highly susceptible to rapid and irreversible ice loss. Such losses have the potential to elevate global sea levels by more than half a meter within centuries.
While it remains uncertain how this newfound knowledge of subglacial geology will affect predictions of ice flow and loss from Thwaites Glacier and other neighboring glaciers, the study does indicate that the geological composition significantly impacts basal shear stress, which determines the speed at which ice can flow into the ocean. To gain further insights, the research team plans to conduct in-depth investigations into these processes. Moreover, the acquired data may enable modelers to generate more accurate projections of future ice loss.
Professor Bernd Kulessa from Swansea University’s geography department emphasized the importance of this study in understanding future sea level rise: “The ongoing rapid retreat of the Thwaites Glacier is arguably one of the greatest uncertainties in future sea level rise predictions. By combining a series of airborne geophysical datasets and analyzing them using state-of-the-science concepts, our study reveals the geology beneath the ice for the first time. This is important because the glacier ice can slip more easily over some types of rock than others, and geothermal heating will help the ice to slip even faster in some areas. Our study, therefore, provides an exciting and novel basis for better predictions of future Thwaites Glacier ice flow and sea level rise.”
Professor Tom Jordan added, “We hope that by showcasing the detailed geology and its correlation with basal friction, future models of glacial retreat will exhibit reduced uncertainty, as we gain a better understanding of the controls governing basal processes.”
Although climate change poses an immense challenge that no single scientific study can fully address, it is through incremental progress in research endeavors like this that we can grasp and confront this daunting issue.
Reference: “Geological sketch map and implications for ice flow of Thwaites Glacier, West Antarctica, from integrated aerogeophysical observations” by Tom A. Jordan, Sarah Thompson, Bernd Kulessa, and Fausto Ferraccioli, 31 May 2023, Science Advances.
DOI: 10.1126/sciadv.adf2639
Professor Kulessa’s involvement in the GHOST project (Geophysical Habitats of Subglacial Thwaites) highlights his contribution as a UK investigator. GHOST is one of the eight major scientific projects jointly funded by the US National Science Foundation and the UK Natural Environment Research Council as part of the International Thwaites Glacier Collaboration.
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Frequently Asked Questions (FAQs) about Antarctica’s vulnerable glacier mapping
What is the significance of mapping the ground beneath Thwaites Glacier in Antarctica?
Mapping the ground beneath Thwaites Glacier is significant because it provides vital insights into the glacier’s susceptibility to climate change. Understanding the subglacial geology helps predict the glacier’s behavior as it retreats and provides valuable information for estimating ice flow and potential sea level rise.
How was the mapping of the subglacial geology of Thwaites Glacier conducted?
The mapping was conducted using airborne surveys with radar-equipped aircraft capable of penetrating the ice and detecting the underlying rock formations. Gravity and magnetism sensors were also used to gather data about the subsurface layers beneath the glacier.
What did the study reveal about Thwaites Glacier’s subglacial geology?
The study revealed a scarcity of sedimentary rock beneath Thwaites Glacier, which was an unexpected outcome. This finding has implications for the glacier’s movement into the ocean in the coming decades. Understanding the distribution of sediments helps predict how fast the glacier will flow and how it may contribute to future sea level rise.
How does the geology beneath the ice influence Thwaites Glacier’s behavior?
The geology beneath the ice plays a crucial role in determining how the glacier moves and interacts with the ocean. Sediments allow for faster flow, while different types of rock offer varying levels of resistance. By mapping the slippery sediments and understanding the basal shear stress, scientists can make more accurate predictions about the glacier’s retreat and its impact on sea level rise.
How does this research contribute to future projections of ice loss and sea level rise?
By providing detailed insights into the subglacial geology of Thwaites Glacier, this research helps reduce uncertainties in future models of glacial retreat. The knowledge gained about basal processes and the controls governing ice flow allows for more reliable projections of ice loss and its potential contribution to global sea level rise.
More about Antarctica’s vulnerable glacier mapping
- British Antarctic Survey: Link
- Swansea University Geography Department: Link
- Science Advances Journal: Link
- International Thwaites Glacier Collaboration: Link
- GHOST Project: Link
