the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 16 Apr 2026
Glacier surges on James Ross Island, Antarctica, and their relationship with climate
Abstract. Although the Antarctic Peninsula has a similar climate to that of other regions hosting surge-type glaciers, only one glacier surge has been previously observed in this region. We examined ice surface velocity, elevation and terminus position changes of Antarctic Peninsula glaciers to identify glacier surges. This revealed only four surges from three glaciers, all on James Ross Island. Gourdon Glacier surged from 2005 to 2007 then again from 2013 to 2018, Kotick Glacier surged during 2013 to 2017 and Whisky Glacier surged from 2020 to 2024. All four surges were characterised by significant advances in glacier terminus position and, for the latter three surges where observations are more abundant, at least an order-of-magnitude speed-up and mass transfer from upper to lower parts of each glacier. The landform record and historical imagery suggest additional surges of Kotick Glacier and Gourdon Glacier may have occurred in the second half of the 20th century. Reanalyses, reconstructions and observations of air temperature suggest that atmospheric warming since 1940 has increasingly exposed these and neighbouring glaciers on the northern tip of the Antarctic Peninsula and its surrounding islands to conditions that are typical of surge-type glaciers globally. Climate projections indicate that future warming will expose more glaciers on the Peninsula to climatic conditions conducive to surging until the mid-20th century, after which the surge-conducive area remains steady under Shared Socioeconomic Pathway (SSP) 2-4.5 and declines under SSP5-8.5. This suggests that surges on the Antarctic Peninsula may become more common over the coming decades, motivating continued monitoring.
Competing interests: At least one of the (co-)authors is a member of the editorial board of The Cryosphere.
Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this paper. While Copernicus Publications makes every effort to include appropriate place names, the final responsibility lies with the authors. Views expressed in the text are those of the authors and do not necessarily reflect the views of the publisher.- Preprint
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Status: open (until 28 May 2026)
- RC1: 'Comment on egusphere-2026-1894', Anonymous Referee #1, 26 May 2026 reply
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- 1
General comments
The authors present a study on recent glacier surges on James Ross Island, northern Antarctic Peninsula region, based on satellite observations of ice flow velocity, surface elevation change and terminus position. The report on the glacier surges is complemented by an extended account on the potential occurrence of surge-type glaciers on the Antarctic Peninsula and in other regions of Antarctica in the 1940 to 2150 time frame, using a predictor based on meteorological reanalysis data, respectively climate model projections under two different warming scenarios.
The analysis of the satellite data revealed four surges on three glaciers during the period 2005 to 2025. For one of the potential surges (Gourdon Glacier 2005) the data base is rather thin, insufficient for definite proof of a surge. Another case of ice flow acceleration (Kotick Glacier 2015) has been reported by Stinger et al. (2025) as a potential surge and surveyed with an enhanced data base by Davidson et al. (Section 3.3 of this manuscript). The discovery and description of surges in Antarctica is a topic of significant interest per se. Beyond that, detailed descriptions of surges are able to provide valuable information on the dynamic response of glaciers to changes of glacier mass, glacier geometry and climate. In case of the surges presented in the manuscript, the analysis of driving factors for the individual surges is partly affected by the limited quality and completeness of velocity data which vary between individual glaciers and time periods. For one event (Whisky Glacier) the drainage of a subglacial lake has been identified as one of the main triggers.
At large, the presented work on the James Ross Island surges opens up a new topic in the context of Antarctic glacier studies, contributing to the understanding of the multifaceted dynamic behaviour of the glaciers. The manuscript would benefit from more detailed descriptions of surge evolution in space and time and discussion on possible mechanisms for triggering and sustaining the different surges. Estimates on the transfer of ice mass induced by the surges would also be of interest.
The presentation on the potential occurrence of glacier surges in various region of Antarctica conveys rather limited new information. The probability for the occurrence of surge-type glaciers is computed using the Surging Climatic Envelope (SCE) which has been defined by the climate conditions of regions with surging glaciers observed during the last several decades. Based on the SCE and climate reanalysis data and climate projections, occurrence probabilities in between 1940 and 2150 are computed. For selected years probability levels are delineated in maps of the Antarctic Peninsula and Antarctica. Taking into account that the current version of the SCE is based on valley glaciers, it is rather questionable if it is applicable for exploring the potential surge occurrence for outlet glaciers and ice streams of Antarctica and if the surge behaviour will be of relevance for future losses of the Antarctic ice mass. In view of these issues, I recommend shortening the sections dealing with the climatic envelope for surges.
Further Comments
Information on glacier properties: Main attributes of the three glaciers should be specified, including glacier size, hypsometry, altitude of equilibrium line, estimates of surface mass balance parameters. The size of the floating terminus section and grounding line location before and after the surge should also be quoted (if existing). In this context, possible impacts of oceanic forcing may be addressed.
Fig. 1 a and b: Please check the orientation of the marker for the North direction.
Fig 1 c (Kotick Glacier): Please add a km scale.
Fig. 1, upper right panel: Hardly possible capturing the exact location and setting of the study glaciers within the surface velocity image. I recommend showing this image separately in larger size.
Line 142 – 152: Taking into account the mismatch between the large size of the velocity estimation windows in comparison to the comparatively small size of the surging glaciers and the complex ice motion patterns during surges, the error estimates should be re-considered. The scatter of velocity data points in points in Fig 2 is also an indication for higher uncertainties.
Section 2.2 Surface elevation change: Please provide an error estimate for the calculated surface elevation change.
Line 220 to 222: Please specify the locations to which the velocities of 40, 200 and 800 m/yr refer. Fig. 2k shows a large spread of velocities at any time.
Line 231: Changes of the terminus position are shown in Fig. 2m.
Section 3.2, Gourdon Glacier: Whereas the data base for the terminus advance in 2005 is rather thin, the data of the 2013 to 2017 event represents a convenient basis for exploring in detail the different phases of the surge and the progress of velocity changes and mass transfer along the terminus. For this task, velocities along the central flowline may be shown on different dates, or time series of velocity at several points in different sections of the glacier, rather than only for one point as shown in Fig. 4k.
Line 268 – 270: Please explain the processes causing thickening in the upper reaches of the glacier and continuous lowering downstream, and how this is reflected in estimates of the mass transfer.
Kotik Glacier, Line 273 – 283 and Figure 5: The data presented in Figures 5k and 5l and the discussion do not provide sufficient information for clearly describing the development and progress of the surge and for exploring possible driving mechanisms. Time series of surface velocity and elevation change should be shown also for other sections of the glacier rather than only for one point on the lower terminus. Another issue to be explained is the cause for the rather constant gradual decrease of surface elevation between 2015 and 2025 (Fig. 5), in spite of a large drop of velocity in 2017.
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