Stability of the Antarctic Ice Sheet during the pre-industrial Holocene

Jones, Richard S.; Johnson, Joanne S.; Lin, Yucheng; Mackintosh, Andrew; Sefton, Juliet; Smith, James A; Thomas, Elizabeth R.; Whitehouse, Pippa L.

doi:10.1038/s43017-022-00309-5

Cited by 30 publications

(23 citation statements)

References 241 publications

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“…However, because the WAIS is also sensitive to ice-dynamical changes at the ice-sheet margins (e.g. GL retreat and/or calving), an increase in accumulation rates in the upper part of the ice sheet may not necessarily result in enough thickening to counteract potential losses from ice dynamics further downstream (Jones et al, 2022). The lack of an ice-dynamical component in the model used here precludes us from reaching such a conclusion; however, higher accumulation rates of up to 18% during the mid-Holocene across 30% of the WAIS would likely be consistent with an increase of several tens of meters in ice thickness (e.g.…”

Section: Discussionmentioning

confidence: 99%

“…sectors initially retreated from the LGM inland until ~9.7 -10.2 ka, and then re-advanced to its modern position sometime during the Holocene. Although they attributed this change in GL position to the solid Earth viscoelastic response due to ice-sheet mass change and the subsequent re-grounding around pinning points, it has also been suggested that an increase in accumulation rates upstream of the GL could lead to a re-advance via ice thickening there and a subsequent increase in ice flow (Steig et al, 2001;Koutnik et al, 2016;Jones et al, 2022).…”

Section: Discussionmentioning

confidence: 99%

“…Johnson et al, 2021). While improvements in model physics and parameterisations are needed to close this gap (Bracegirdle et al, 2019;Sutter et al, 2021), a considerable improvement in the availability and quality of palaeo-proxy records, particularly during the Holocene, is also needed to gain a more accurate picture of the past ice-sheet changes (Jones et al, 2022). Palaeo-proxy data over the WAIS have traditionally come from point-based measurements, such as ice cores (WAIS Divide Project Members, 2013;McConnell et al, 2017;Buizert et al, 2021), sediment cores (Hillenbrand et al, 2013;Arnd et al, 2017;Hillenbrand et al, 2017;Kingslake et al, 2018;Venturelli et al, 2020;Neuhaus et al, 2021;Sproson et al, 2022), or from surface-exposure dating (Stone et al, 2003;Johnson et al, 2014;Hein et al, 2016;Nichols et al, 2019;Johnson et al, 2020;Braddock et al, 2022).…”

Section: Introductionmentioning

confidence: 99%

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High mid-Holocene accumulation rates over West Antarctica inferred from a pervasive ice-penetrating radar reflector

Bodart

Bingham²,

Young³

et al. 2022

Preprint

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Abstract. Modelling the past and future evolution of the West Antarctic Ice Sheet (WAIS) to atmospheric and ocean forcing is challenged by the availability and quality of observed palaeo-boundary conditions. Key potential data for reconstructing past ice-sheet processes on large spatial scales are Internal Reflecting Horizons (IRHs) detected by Radio-Echo Sounding (RES) techniques. When isochronal and dated at ice cores, IRHs can be used to determine palaeo-accumulation rates and patterns. Using a spatially extensive IRH over Pine Island Glacier, Thwaites Glacier, Institute and Möller Ice Streams, and a local layer approximation model, we infer mid-Holocene accumulation rates over the slow-flowing parts of these catchments for the past ~5000 years. By comparing our results with modern climate reanalysis models and observational syntheses, we estimate that accumulation rates over the Amundsen-Weddell-Ross divide were on average 18 % higher than modern rates during the mid-Holocene. However, no significant spatial changes in the accumulation pattern were observed. These higher mid-Holocene accumulation-rate estimates match previous palaeo-accumulation estimates from ice-core and targeted IPR surveys over the ice divide, and also coincide with periods of grounding-line re-advance during the Holocene over the Weddell and Ross Sea sectors. Our results highlight the need for ice-sheet models to account for time-varying accumulation rates across the WAIS during the Holocene to provide better estimates of its contribution to past sea-level rise.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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High mid-Holocene accumulation rates over West Antarctica inferred from a pervasive ice-penetrating radar reflector

Bodart

Bingham²,

Young³

et al. 2022

Preprint

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“…Recent studies 12,[29][30][31] suggest that during the Holocene, the meltwater contribution of the AIS was comparatively modest. A small Antarctic contribution from 9 to 7 ka is supported by our RSL data (Fig.…”

Section: Data-model Comparison and Meltwater Partitioningmentioning

confidence: 99%

Revised constraints on the final stages of the last deglaciation from high-resolution sea-level observations

MUKHERJEE,

Vetter,

Milne

et al. 2024

Preprint

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The rapid transformation of the ocean-atmosphere-cryosphere system during the last deglaciation serves as a potential model for climate change during this century and beyond. Within this context, sea-level change can be viewed as the connecting tissue, but the limited resolution of relative sea-level (RSL) records has hindered progress toward closing the ice sheet–sea level budget since the Last Glacial Maximum, the partitioning of ice melt from different sources, and assessing the role of freshwater forcing in abrupt climate change. Here we present a new RSL record from the Mississippi Delta stretching back to 11 ka and combine it with the best available published RSL data worldwide for the final episode of the last deglaciation (9-7 ka). Glacial isostatic adjustment (GIA) modelling shows that these precise data constraints demand a North American ice melt of about 14 m sea-level equivalent (SLE) during this time, 4-10 m greater than previously estimated. Our results call for a major revision of the North American deglacial ice history and our findings demonstrate the utility of high-resolution RSL observations as a pathway towards closing the ice budget of the last deglaciation and improving our understanding of the ocean-atmosphere-cryosphere system during rapid climate change.

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“…As a result, uncertainty of our projections is dominated by the unknown strength of marine ice‐sheet feedbacks and internal climate variability (Robel et al., 2019). Records of ice‐sheet change in the geologic past (i.e., paleoglaciological reconstructions) provide a pathway for constraining the limits of ice‐mass changes over societally relevant timescales (Jones et al., 2022; Kopp et al., 2016), and as a result, may reduce the uncertainty envelope in projections of future sea level rise (e.g., DeConto et al., 2021).…”

Section: Introductionmentioning

confidence: 99%

Constraints on the Timing and Extent of Deglacial Grounding Line Retreat in West Antarctica

et al. 2023

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Projections of Antarctica's contribution to future sea level rise are associated with significant uncertainty, in part because the observational record is too short to capture long‐term processes necessary to estimate ice mass changes over societally relevant timescales. Records of grounding line retreat from the geologic past offer an opportunity to extend our observations of these processes beyond the modern record and to gain a more comprehensive understanding of ice‐sheet change. Here, we present constraints on the timing and inland extent of deglacial grounding line retreat in the southern Ross Sea, Antarctica, obtained via direct sampling of a subglacial lake located 150 km inland from the modern grounding line and beneath >1 km of ice. Isotopic measurements of water and sediment from the lake enabled us to evaluate how the subglacial microbial community accessed radiocarbon‐bearing organic carbon for energy, as well as where it transferred carbon metabolically. Using radiocarbon as a natural tracer, we found that sedimentary organic carbon was microbially translocated to dissolved carbon pools in the subglacial hydrologic system during the 4.5‐year period of water accumulation prior to our sampling. This finding indicates that the grounding line along the Siple Coast of West Antarctica retreated more than 250 km inland during the mid‐Holocene (6.3 ± 1.0 ka), prior to re‐advancing to its modern position.

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Stability of the Antarctic Ice Sheet during the pre-industrial Holocene

Cited by 30 publications

References 241 publications

High mid-Holocene accumulation rates over West Antarctica inferred from a pervasive ice-penetrating radar reflector

High mid-Holocene accumulation rates over West Antarctica inferred from a pervasive ice-penetrating radar reflector

Revised constraints on the final stages of the last deglaciation from high-resolution sea-level observations

Constraints on the Timing and Extent of Deglacial Grounding Line Retreat in West Antarctica

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