Articles | Volume 15, issue 12
https://doi.org/10.5194/tc-15-5705-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/tc-15-5705-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Brief communication
| Highlight paper
| 
17 Dec 2021
Brief communication | Highlight paper |
| 17 Dec 2021
| 17 Dec 2021
Brief communication: A roadmap towards credible projections of ice sheet contribution to sea level
Geophysical Institute, University of Alaska Fairbanks, Fairbanks, Alaska, USA
Timothy C. Bartholomaus
Department of Earth and Spatial Sciences, University of Idaho, Moscow, Idaho, USA
Douglas J. Brinkerhoff
Department of Computer Science, University of Montana, Missoula, MT, USA
Martin Truffer
Geophysical Institute, University of Alaska Fairbanks, Fairbanks, Alaska, USA
Related authors
Andrew Nolan, Gwenn E. Flowers, Andy Aschwanden, and Adrien Gilbert
EGUsphere, https://doi.org/10.5194/egusphere-2026-913, https://doi.org/10.5194/egusphere-2026-913, 2026
This preprint is open for discussion and under review for The Cryosphere (TC).
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We used a computer model to study the effects of glacier "surges", or unusual fast-flow events, on the distribution of ice temperature in a glacier. The purpose of the study was to examine feedbacks that might influence the form and flow of these glaciers in a stable climate. We found surging glaciers to be smaller and colder than their ordinary counterparts, while strong regular surges induced an oscillation in glacier temperature and flow speed much longer than the interval between surges.
Joseph A. MacGregor, Mark A. Fahnestock, John D. Paden, Jilu Li, Jeremy P. Harbeck, and Andy Aschwanden
Earth Syst. Sci. Data, 17, 2911–2931, https://doi.org/10.5194/essd-17-2911-2025, https://doi.org/10.5194/essd-17-2911-2025, 2025
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This paper describes the second version of a deep radiostratigraphic database for the Greenland Ice Sheet. It includes numerous improvements to the original database from 2015 and includes newer high-quality radar sounding data from 2014–2019. It represents a unique and widespread constraint on the history of the ice sheet that could be helpful to initialize and interpret ice-sheet models.
Anja Løkkegaard, Kenneth D. Mankoff, Christian Zdanowicz, Gary D. Clow, Martin P. Lüthi, Samuel H. Doyle, Henrik H. Thomsen, David Fisher, Joel Harper, Andy Aschwanden, Bo M. Vinther, Dorthe Dahl-Jensen, Harry Zekollari, Toby Meierbachtol, Ian McDowell, Neil Humphrey, Anne Solgaard, Nanna B. Karlsson, Shfaqat A. Khan, Benjamin Hills, Robert Law, Bryn Hubbard, Poul Christoffersen, Mylène Jacquemart, Julien Seguinot, Robert S. Fausto, and William T. Colgan
The Cryosphere, 17, 3829–3845, https://doi.org/10.5194/tc-17-3829-2023, https://doi.org/10.5194/tc-17-3829-2023, 2023
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This study presents a database compiling 95 ice temperature profiles from the Greenland ice sheet and peripheral ice caps. Ice viscosity and hence ice flow are highly sensitive to ice temperature. To highlight the value of the database in evaluating ice flow simulations, profiles from the Greenland ice sheet are compared to a modeled temperature field. Reoccurring discrepancies between modeled and observed temperatures provide insight on the difficulties faced when simulating ice temperatures.
Andrew Nolan, Gwenn E. Flowers, Andy Aschwanden, and Adrien Gilbert
EGUsphere, https://doi.org/10.5194/egusphere-2026-913, https://doi.org/10.5194/egusphere-2026-913, 2026
This preprint is open for discussion and under review for The Cryosphere (TC).
Short summary
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We used a computer model to study the effects of glacier "surges", or unusual fast-flow events, on the distribution of ice temperature in a glacier. The purpose of the study was to examine feedbacks that might influence the form and flow of these glaciers in a stable climate. We found surging glaciers to be smaller and colder than their ordinary counterparts, while strong regular surges induced an oscillation in glacier temperature and flow speed much longer than the interval between surges.
Douglas J. Brinkerhoff, Brandon S. Tober, Michael Daniel, Victor Devaux-Chupin, Michael S. Christoffersen, John W. Holt, Christopher F. Larsen, Mark Fahnestock, Michael G. Loso, Kristin M. F. Timm, Russell C. Mitchell, and Martin Truffer
The Cryosphere, 19, 2321–2353, https://doi.org/10.5194/tc-19-2321-2025, https://doi.org/10.5194/tc-19-2321-2025, 2025
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Sít' Tlein is one of the largest glaciers in the world outside of the polar regions, and we know that it has been rapidly thinning. To forecast how this glacier will change in the future, we combine a computer model of ice flow with measurements from many different sources. Our model tells us that with high probability, Sít' Tlein's lower reaches are going to disappear in the next century and a half, creating a new bay or lake along Alaska's coastline.
Joseph A. MacGregor, Mark A. Fahnestock, John D. Paden, Jilu Li, Jeremy P. Harbeck, and Andy Aschwanden
Earth Syst. Sci. Data, 17, 2911–2931, https://doi.org/10.5194/essd-17-2911-2025, https://doi.org/10.5194/essd-17-2911-2025, 2025
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This paper describes the second version of a deep radiostratigraphic database for the Greenland Ice Sheet. It includes numerous improvements to the original database from 2015 and includes newer high-quality radar sounding data from 2014–2019. It represents a unique and widespread constraint on the history of the ice sheet that could be helpful to initialize and interpret ice-sheet models.
Natalie Lützow, Bretwood Higman, Martin Truffer, Bodo Bookhagen, Friedrich Knuth, Oliver Korup, Katie E. Hughes, Marten Geertsema, John J. Clague, and Georg Veh
The Cryosphere, 19, 1085–1102, https://doi.org/10.5194/tc-19-1085-2025, https://doi.org/10.5194/tc-19-1085-2025, 2025
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As the atmosphere warms, thinning glacier dams impound smaller lakes at their margins. Yet, some lakes deviate from this trend and have instead grown over time, increasing the risk of glacier floods to downstream populations and infrastructure. In this article, we examine the mechanisms behind the growth of an ice-dammed lake in Alaska. We find that the growth in size and outburst volumes is more controlled by glacier front downwaste than by overall mass loss over the entire glacier surface.
Amy Jenson, Mark Skidmore, Lucas Beem, Martin Truffer, and Scott McCalla
The Cryosphere, 18, 5451–5464, https://doi.org/10.5194/tc-18-5451-2024, https://doi.org/10.5194/tc-18-5451-2024, 2024
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Water in some glacier environments contains salt, which increases its density and lowers its freezing point, allowing saline water to exist where freshwater cannot. Previous subglacial hydrology models do not consider saline fluid. We model the flow of saline fluid from a subglacial lake through a circular channel at the glacier bed, finding that higher salinities lead to less melting at the channel walls and lower discharge rates. We also observe the impact of increased fluid density on flow.
Nicole Abib, David A. Sutherland, Rachel Peterson, Ginny Catania, Jonathan D. Nash, Emily L. Shroyer, Leigh A. Stearns, and Timothy C. Bartholomaus
The Cryosphere, 18, 4817–4829, https://doi.org/10.5194/tc-18-4817-2024, https://doi.org/10.5194/tc-18-4817-2024, 2024
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The melting of ice mélange, or dense packs of icebergs and sea ice in glacial fjords, can influence the water column by releasing cold fresh water deep under the ocean surface. However, direct observations of this process have remained elusive. We use measurements of ocean temperature, salinity, and velocity bookending an episodic ice mélange event to show that this meltwater input changes the density profile of a glacial fjord and has implications for understanding tidewater glacier change.
Gabriela Collao-Barrios, Ted A. Scambos, Christian T. Wild, Martin Truffer, Karen E. Alley, and Erin C. Pettit
EGUsphere, https://doi.org/10.5194/egusphere-2024-1895, https://doi.org/10.5194/egusphere-2024-1895, 2024
Preprint archived
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Destabilization of ice shelves frequently leads to significant acceleration and greater mass loss, affecting rates of sea level rise. Our results show a relation between tides, flow direction, and grounding-zone acceleration that result from changing stresses in the ice margins and around a nunatak in Dotson Ice Shelf. The study describes a new way tides can influence ice shelf dynamics, an effect that could become more common as ice shelves thin and weaken around Antarctica.
Naomi E. Ochwat, Ted A. Scambos, Alison F. Banwell, Robert S. Anderson, Michelle L. Maclennan, Ghislain Picard, Julia A. Shates, Sebastian Marinsek, Liliana Margonari, Martin Truffer, and Erin C. Pettit
The Cryosphere, 18, 1709–1731, https://doi.org/10.5194/tc-18-1709-2024, https://doi.org/10.5194/tc-18-1709-2024, 2024
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On the Antarctic Peninsula, there is a small bay that had sea ice fastened to the shoreline (
fast ice) for over a decade. The fast ice stabilized the glaciers that fed into the ocean. In January 2022, the fast ice broke away. Using satellite data we found that this was because of low sea ice concentrations and a high long-period ocean wave swell. We find that the glaciers have responded to this event by thinning, speeding up, and retreating by breaking off lots of icebergs at remarkable rates.
Anja Løkkegaard, Kenneth D. Mankoff, Christian Zdanowicz, Gary D. Clow, Martin P. Lüthi, Samuel H. Doyle, Henrik H. Thomsen, David Fisher, Joel Harper, Andy Aschwanden, Bo M. Vinther, Dorthe Dahl-Jensen, Harry Zekollari, Toby Meierbachtol, Ian McDowell, Neil Humphrey, Anne Solgaard, Nanna B. Karlsson, Shfaqat A. Khan, Benjamin Hills, Robert Law, Bryn Hubbard, Poul Christoffersen, Mylène Jacquemart, Julien Seguinot, Robert S. Fausto, and William T. Colgan
The Cryosphere, 17, 3829–3845, https://doi.org/10.5194/tc-17-3829-2023, https://doi.org/10.5194/tc-17-3829-2023, 2023
Short summary
Short summary
This study presents a database compiling 95 ice temperature profiles from the Greenland ice sheet and peripheral ice caps. Ice viscosity and hence ice flow are highly sensitive to ice temperature. To highlight the value of the database in evaluating ice flow simulations, profiles from the Greenland ice sheet are compared to a modeled temperature field. Reoccurring discrepancies between modeled and observed temperatures provide insight on the difficulties faced when simulating ice temperatures.
Chris Miele, Timothy C. Bartholomaus, and Ellyn M. Enderlin
The Cryosphere, 17, 2701–2704, https://doi.org/10.5194/tc-17-2701-2023, https://doi.org/10.5194/tc-17-2701-2023, 2023
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Vertical shear stress (the stress orientation usually associated with vertical gradients in horizontal velocities) is a key component of the stress balance of ice shelves. However, partly due to historical assumptions, vertical shear is often misspoken of today as
negligiblein ice shelf models. We address this miscommunication, providing conceptual guidance regarding this often misrepresented stress. Fundamentally, vertical shear is required to balance thickness gradients in ice shelves.
Marin Kneib, Evan S. Miles, Pascal Buri, Stefan Fugger, Michael McCarthy, Thomas E. Shaw, Zhao Chuanxi, Martin Truffer, Matthew J. Westoby, Wei Yang, and Francesca Pellicciotti
The Cryosphere, 16, 4701–4725, https://doi.org/10.5194/tc-16-4701-2022, https://doi.org/10.5194/tc-16-4701-2022, 2022
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Ice cliffs are believed to be important contributors to the melt of debris-covered glaciers, but this has rarely been quantified as the cliffs can disappear or rapidly expand within a few weeks. We used photogrammetry techniques to quantify the weekly evolution and melt of four cliffs. We found that their behaviour and melt during the monsoon is strongly controlled by supraglacial debris, streams and ponds, thus providing valuable insights on the melt and evolution of debris-covered glaciers.
Evan Carnahan, Ginny Catania, and Timothy C. Bartholomaus
The Cryosphere, 16, 4305–4317, https://doi.org/10.5194/tc-16-4305-2022, https://doi.org/10.5194/tc-16-4305-2022, 2022
Short summary
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The Greenland Ice Sheet primarily loses mass through increased ice discharge. We find changes in discharge from outlet glaciers are initiated by ocean warming, which causes a change in the balance of forces resisting gravity and leads to acceleration. Vulnerable conditions for sustained retreat and acceleration are predetermined by the glacier-fjord geometry and exist around Greenland, suggesting increases in ice discharge may be sustained into the future despite a pause in ocean warming.
Christian T. Wild, Karen E. Alley, Atsuhiro Muto, Martin Truffer, Ted A. Scambos, and Erin C. Pettit
The Cryosphere, 16, 397–417, https://doi.org/10.5194/tc-16-397-2022, https://doi.org/10.5194/tc-16-397-2022, 2022
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Thwaites Glacier has the potential to significantly raise Antarctica's contribution to global sea-level rise by the end of this century. Here, we use satellite measurements of surface elevation to show that its floating part is close to losing contact with an underwater ridge that currently acts to stabilize. We then use computer models of ice flow to simulate the predicted unpinning, which show that accelerated ice discharge into the ocean follows the breakup of the floating part.
Thiago Dias dos Santos, Mathieu Morlighem, and Douglas Brinkerhoff
The Cryosphere, 16, 179–195, https://doi.org/10.5194/tc-16-179-2022, https://doi.org/10.5194/tc-16-179-2022, 2022
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Projecting the future evolution of Greenland and Antarctica and their potential contribution to sea level rise often relies on computer simulations carried out by numerical ice sheet models. Here we present a new vertically integrated ice sheet model and assess its performance using different benchmarks. The new model shows results comparable to a three-dimensional model at relatively lower computational cost, suggesting that it is an excellent alternative for long-term simulations.
Karen E. Alley, Christian T. Wild, Adrian Luckman, Ted A. Scambos, Martin Truffer, Erin C. Pettit, Atsuhiro Muto, Bruce Wallin, Marin Klinger, Tyler Sutterley, Sarah F. Child, Cyrus Hulen, Jan T. M. Lenaerts, Michelle Maclennan, Eric Keenan, and Devon Dunmire
The Cryosphere, 15, 5187–5203, https://doi.org/10.5194/tc-15-5187-2021, https://doi.org/10.5194/tc-15-5187-2021, 2021
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We present a 20-year, satellite-based record of velocity and thickness change on the Thwaites Eastern Ice Shelf (TEIS), the largest remaining floating extension of Thwaites Glacier (TG). TG holds the single greatest control on sea-level rise over the next few centuries, so it is important to understand changes on the TEIS, which controls much of TG's flow into the ocean. Our results suggest that the TEIS is progressively destabilizing and is likely to disintegrate over the next few decades.
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Short summary
Estimating how much ice loss from Greenland and Antarctica will contribute to sea level rise is of critical societal importance. However, our analysis shows that recent efforts are not trustworthy because the models fail at reproducing contemporary ice melt. Here we present a roadmap towards making more credible estimates of ice sheet melt.
Estimating how much ice loss from Greenland and Antarctica will contribute to sea level rise is...
