the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 20 Mar 2025
Simulating the Holocene evolution of Ryder Glacier, North Greenland
Abstract. The Greenland Ice Sheet's negative mass balance is driven by a sensitivity to both a warming atmosphere and ocean. The fidelity of ice-sheet models in accounting for ice-ocean interaction is inherently uncertain and often constrained against recent fluctuations in the ice-sheet margin from the previous decades. The geological record can be utilised to contextualise ice-sheet mass loss and understand the drivers of changes at the marine margin across climatic shifts and previous extended warm periods, aiding our understanding of future ice-sheet behaviour. Here, we use the Ice-sheet and Sea-level System Model (ISSM) to explore the Holocene evolution of Ryder Glacier draining into Sherard Osborn Fjord, Northern Greenland. Our modelling results are constrained with terrestrial reconstructions of the paleo-ice sheet margin and an extensive marine sediment record from Sherard Osborn Fjord that details ice dynamics over the past 12.5 ka years. By employing a consistent mesh resolution of <1 km at the ice-ocean boundary, we assess the importance of atmospheric and oceanic changes to Ryder Glacier's Holocene behaviour. Our simulations show that the initial retreat of the ice margin after the Younger Dryas cold period was driven by a warming climate and the resulting fluctuations in Surface Mass Balance. Changing atmospheric conditions remain the first order control in the timing of ice retreat during the Holocene. We find ice-ocean interactions become increasingly fundamental to Ryder's retreat in the mid-Holocene; with higher than contemporary melt rates required to force grounding line retreat and capture the collapse of the ice tongue during the Holocene Thermal Maximum. Regrowth of the tongue during the neo-glacial cooling of the late Holocene is necessary to advance both the terrestrial and marine margins of the glacier. Our results stress the importance of accurately resolving the ice-ocean interface in modelling efforts over centennial and millennial time scales, in particular the role of floating ice tongues and submarine melt, and provide vital analogous for the future evolution of Ryder in a warming climate.
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Notice on discussion status
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
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Preprint
(13788 KB)
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The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
- Preprint
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- Final revised paper
Journal article(s) based on this preprint
Interactive discussion
Status: closed
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RC1: 'Comment on egusphere-2025-653', Anonymous Referee #1, 27 Mar 2025
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AC1: 'Reply on RC1', Jamie Barnett, 23 Jun 2025
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2025/egusphere-2025-653/egusphere-2025-653-AC1-supplement.pdf
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AC1: 'Reply on RC1', Jamie Barnett, 23 Jun 2025
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RC2: 'Comment on egusphere-2025-653', Anonymous Referee #2, 30 May 2025
Review of ‘Simulating the Holocene evolution of Ryder Glacier, North Greenland’
Manuscript Summary
This manuscript presents the results of ISSM simulations of Ryder Glacier, North Greenland, through the Holocene, constrained by preexisting terrestrial reconstructions and marine sediment records. They aim to better understand the drivers of Holocene ice sheet retreat and advance. Their results show that retreat following the Younger Dryas was SMB driven, with ice-ocean interactions becoming more important during the mid-Holocene. They also demonstrate that the Neoglacial advance of Ryder Glacier requires ice tongue regrowth, which required both cooling ocean temperatures and air temperatures.
The manuscript is well-written and structured, effectively addressing the paper's objectives. It is very well illustrated, which helps me (and any reader) to understand what is being presented. The interpretations are clear and well supported by the results presented.
I don’t have many major criticisms or concerns with the paper, but I think some aspects of the writing should be improved. There are numerous typos and incorrect word choices which limit the understanding of the content at times. I’ve included some below, but there are more.
Minor comments:
- The decision behind the choice of model is not very clearly explained. Given the dependence of the paper on this, and as a non-modelling expert, I feel it would be beneficial to explain the choices for this glaciological and topographic situation.
- You discuss the Steensby Stade as the last part of the Holocene glacial history of North Greenland, and also discuss the late Holocene advance, which reached its maximum at the LIA. Are these the same advance – i.e. both culminated in the LIA? I think some clarity should be given about this – including the LIA limit. In Fig 2a you label the two previous Stades, and in Fig. 2b you have the LIA (offshore) limit labelled. Is this LIA actually limit actually recorded, I had a quick look at the Koch (1928) reference and couldn’t see how this limit was recorded. Is there an onshore expression of the LIA too?
- Younger Dryas spin up: you say that you are assuming that the Ryder Glacier was stable during the Younger Dryas. Is there any evidence to back this up? The YD in Greenland is very enigmatic, and there is often little evidence for a stillstand, moraine formation, or dramatic slowdown during it (unless I am mistaken). So I’d slightly caution the statement that the glacier was stable at this point in time.
- L154: 12,500 BP until 2000 CE is 14,500 years, not 12,500.
- P230: Is using the calving threshold for Petermann glacier here valid? Especially as the Petermann simulation was for present day conditions.
- Section 5.3 – the recent work on Nioghalvfjerdsbræ (79N) is partially included here (Smith et al. 2023), but further work has been completed here, in a similar setting (floating ice tongue collapse). Some further discussion of differences or similarities in forcings could be pertinent, as there is both offshore and onshore data.
- L468: This may just be due to strange phrasing, but calving wouldn’t have an impact on the terrestrial ice margin, unless you mean indirect impact in comparison to adjacent marine areas?
Citation: https://doi.org/10.5194/egusphere-2025-653-RC2 -
AC2: 'Reply on RC2', Jamie Barnett, 23 Jun 2025
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2025/egusphere-2025-653/egusphere-2025-653-AC2-supplement.pdf
Interactive discussion
Status: closed
-
RC1: 'Comment on egusphere-2025-653', Anonymous Referee #1, 27 Mar 2025
-
AC1: 'Reply on RC1', Jamie Barnett, 23 Jun 2025
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2025/egusphere-2025-653/egusphere-2025-653-AC1-supplement.pdf
-
AC1: 'Reply on RC1', Jamie Barnett, 23 Jun 2025
-
RC2: 'Comment on egusphere-2025-653', Anonymous Referee #2, 30 May 2025
Review of ‘Simulating the Holocene evolution of Ryder Glacier, North Greenland’
Manuscript Summary
This manuscript presents the results of ISSM simulations of Ryder Glacier, North Greenland, through the Holocene, constrained by preexisting terrestrial reconstructions and marine sediment records. They aim to better understand the drivers of Holocene ice sheet retreat and advance. Their results show that retreat following the Younger Dryas was SMB driven, with ice-ocean interactions becoming more important during the mid-Holocene. They also demonstrate that the Neoglacial advance of Ryder Glacier requires ice tongue regrowth, which required both cooling ocean temperatures and air temperatures.
The manuscript is well-written and structured, effectively addressing the paper's objectives. It is very well illustrated, which helps me (and any reader) to understand what is being presented. The interpretations are clear and well supported by the results presented.
I don’t have many major criticisms or concerns with the paper, but I think some aspects of the writing should be improved. There are numerous typos and incorrect word choices which limit the understanding of the content at times. I’ve included some below, but there are more.
Minor comments:
- The decision behind the choice of model is not very clearly explained. Given the dependence of the paper on this, and as a non-modelling expert, I feel it would be beneficial to explain the choices for this glaciological and topographic situation.
- You discuss the Steensby Stade as the last part of the Holocene glacial history of North Greenland, and also discuss the late Holocene advance, which reached its maximum at the LIA. Are these the same advance – i.e. both culminated in the LIA? I think some clarity should be given about this – including the LIA limit. In Fig 2a you label the two previous Stades, and in Fig. 2b you have the LIA (offshore) limit labelled. Is this LIA actually limit actually recorded, I had a quick look at the Koch (1928) reference and couldn’t see how this limit was recorded. Is there an onshore expression of the LIA too?
- Younger Dryas spin up: you say that you are assuming that the Ryder Glacier was stable during the Younger Dryas. Is there any evidence to back this up? The YD in Greenland is very enigmatic, and there is often little evidence for a stillstand, moraine formation, or dramatic slowdown during it (unless I am mistaken). So I’d slightly caution the statement that the glacier was stable at this point in time.
- L154: 12,500 BP until 2000 CE is 14,500 years, not 12,500.
- P230: Is using the calving threshold for Petermann glacier here valid? Especially as the Petermann simulation was for present day conditions.
- Section 5.3 – the recent work on Nioghalvfjerdsbræ (79N) is partially included here (Smith et al. 2023), but further work has been completed here, in a similar setting (floating ice tongue collapse). Some further discussion of differences or similarities in forcings could be pertinent, as there is both offshore and onshore data.
- L468: This may just be due to strange phrasing, but calving wouldn’t have an impact on the terrestrial ice margin, unless you mean indirect impact in comparison to adjacent marine areas?
Citation: https://doi.org/10.5194/egusphere-2025-653-RC2 -
AC2: 'Reply on RC2', Jamie Barnett, 23 Jun 2025
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2025/egusphere-2025-653/egusphere-2025-653-AC2-supplement.pdf
Peer review completion
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Felicity Alice Holmes
Joshua Cuzzone
Henning Åkesson
Mathieu Morlighem
Matt O'Regan
Johan Nilsson
Nina Kirchner
Martin Jakobsson
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
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