Early Last Interglacial ocean warming drove substantial ice mass loss from Antarctica

Turney, Chris S. M.; Fogwill, Christopher J.; Golledge, Nicholas R.; McKay, Nicholas P.; Sebille, Erik van; Jones, Richard T.; Etheridge, D. M.; Rubino, Mauro; Thornton, D.; Davies, Siwan M.; Ramsey, Christopher Bronk; Thomas, Zoë; Bird, Michael I.; Munksgaard, Neils; Kohno, Mika; Woodward, John; Winter, Kate; Weyrich, Laura S.; Rootes, Camilla M.; Millman, Helen; Albert, Paul G.; Rivera, Andrés; Curran, Michelle J.; Moy, Andrew D.; Rahmstorf, Stefan; Kawamura, Kenji; Hillenbrand, C. D.; Weber, M.; Manning, Christina; Young, Jennifer M.; Cooper, Alan K.

doi:10.31223/osf.io/dc8jm

Cited by 4 publications

(6 citation statements)

References 9 publications

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“…S6), which, considering our ocean forcing, translates to a 1.5-1.9 • C warming of the ocean surface averaged around Antarctica (i.e., south of 65 • S). This threshold is much lower than the 4 • C stipulated by Tigchelaar et al (2018), but is in line with model results from Turney et al (2020) for the LIG. Our surface ocean temperature threshold should be considered with caution, because it is derived using an interpolation of ocean temperatures to compute our anomalies instead of a coupled ice-ocean setup (a full description is available in the supplementary material).…”

Section: Gissupporting

confidence: 88%

“…It should be noted that the duration of the warming as the key factor for the WAIS collapse is specific to MIS11c. In other words, a more intense albeit shorter peak warming could also trigger WAIS collapse, since a strong rate of warming can drive ice retreat at a much faster pace, which was most likely the case for the LIG (Dutton et al, 2015;Turney et al, 2020).…”

Section: Gismentioning

confidence: 99%

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Sensitivity of the Antarctic ice sheets to the peak warming of Marine Isotope Stage 11

Braga

Bernales

Prange

et al. 2020

Preprint

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Abstract. Studying the response of the Antarctic ice sheets to past climate conditions similar to the present day can provide important insights for understanding its current changes and help identify natural drivers of ice sheet retreat. The Marine Isotope Substage 11c (MIS11c) interglacial is one of the best candidates for an in-depth analysis given that at its later portion orbital parameters were close to our current interglacial. However, Antarctic ice core data indicate that although MIS11c CO2 levels were close to Pre Industrial, warmer-than-present temperatures (of about 2 °C) lasted for much longer than during other interglacials. Since the global mean sea level is thought to have been 6&dash;13 m higher than today, there should have been some contribution from Antarctica. While substantial work has been conducted regarding the response of the Greenland Ice Sheet to the MIS11c climate, which is believed to have contributed with 3.9–7.0 m to global sea level, both configurations of the Antarctic ice sheets and their contribution to sea level rise remain poorly constrained. We use a numerical ice-sheet model to shed light on the response of the Antarctic ice sheets to MIS11c climate conditions obtained from a combination of a suite of Antarctic ice cores and the LR04 global stack of deep-sea sediment records and climate model outputs, while assessing the model sensitivity to the uncertainties in sea level reconstructions, ice sheet initial configuration, and multi-centennial climate variability. We found that the regional climate signal of the MIS11c peak warming in Antarctica captured by the ice core records is necessary for the recorded sea level highstand to be reproduced, and that warming length was more important than magnitude. However, there is a threshold for a West Antarctic Ice Sheet collapse that lies within an envelope of 1.6 and 2.1 °C warmer-than-pre-industrial regional climate conditions. Sea level forcing and multi-centennial variability were found to have played virtually no role in driving ice sheet contraction, but the choice of initial configuration of the East Antarctic Ice Sheet provided a large source of uncertainty in the quantification of MIS11c Antarctic peak sea level contribution, which falls between 6.4 and 8.8 m.

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Section: Gissupporting

confidence: 88%

Section: Gismentioning

confidence: 99%

Sensitivity of the Antarctic ice sheets to the peak warming of Marine Isotope Stage 11

Braga

Bernales

Prange

et al. 2020

Preprint

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“…This is based on revised ice volume constraints for the preceding glacial maximum that consider GIA corrections of a considerably different ice volume distribution (larger Eurasian and smaller North America ice sheets) during the glacial period preceding the LIG, relative to the LGM. If Yau et al (2016) are right and the Greenland contribution to GMSL was ~5 m, then the ~2 m upward adjustment of LIG GMSL estimates of Rohling et al (2017) to 8–11 m above the present‐day level would require Antarctic ice loss during the LIG of ~5 m, even after accounting for an ~1 m contribution from thermal ocean expansion (Turney et al, 2020). Note that this argument does not include asynchroneity in the contributions from Northern and Southern Hemisphere ice sheets, which suggest that the estimated ~5 m Antarctic contribution is a low‐end estimate (Rohling et al, 2019).…”

Section: Evidence For Ice Sheet Changementioning

confidence: 99%

“…Ice and environmental data from the Patriot Hills blue ice region landward of the Weddell Sea Embayment provide evidence for significant ice mass loss during the LIG (Turney et al, 2020). This study is the first direct of substantial WAIS loss during the LIG, which is supported by regional ice sheet modeling results that reinforce the notion of a centennial‐scale (200 year) response time scale to 2°C of ocean warming relative to today.…”

Section: Evidence For Ice Sheet Changementioning

confidence: 99%

The Sensitivity of the Antarctic Ice Sheet to a Changing Climate: Past, Present, and Future

Noble

Rohling

Aitken

et al. 2020

Reviews of Geophysics

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The AIS is an important component of the global climate system. Human activities have caused the atmosphere and especially the oceans to warm. However, the full effect of human caused climate change on the AIS has not currently been realised because the ice sheet responds on a range of timescales and to many different Earth processes. Modern observations show that West Antarctica has been melting at an accelerating rate since the 2000s, while the data for East Antarctica are less clear. Environmental records preserve the history of the climate and AIS, which extend beyond the instrumental record, and reveal how the AIS responded to past climate warming. Estimates of how much the AIS will contribute to sea-level rise by the year 2100 have changed as a result of new information on how the AIS evolved in the past, and research into the interactions between the ice sheet, solid Earthatmosphere and ocean systems. This review brings together our knowledge of the major processes and feedbacks affecting the AIS, and the evidence for how the ice sheet changed since the Pliocene. We consider the future estimates and consequences of global sea-level rise from melting of the AIS, and highlight priority research areas.

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“…This estimate is commonly cited as the maximum contribution of WAIS to peak GMSL during the last interglacial (LIG; ~130 to 116 ka) (19)(20)(21)(22)(23). A total Antarctic contribution to the LIG higher than this would thus imply melt from the East Antarctic Ice Sheet (EAIS) (24)(25)(26). Furthermore, when combined with independent estimates of GMSL changes associated with the Greenland Ice Sheet (18,24,(27)(28)(29), mountain glaciers (30), and thermal expansion (31), the estimate of 3.26 m has led to the view that the lower bound on a widely cited estimate of peak GMSL during the LIG [5.5 to 9 m; (19,32)] requires no contribution from the EAIS, while it is likely that the upper bound does (33).…”

Section: Introductionmentioning

confidence: 99%

Rapid postglacial rebound amplifies global sea level rise following West Antarctic Ice Sheet collapse

et al. 2021

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Geodetic, seismic, and geological evidence indicates that West Antarctica is underlain by low-viscosity shallow mantle. Thus, as marine-based sectors of the West Antarctic Ice Sheet (WAIS) retreated during past interglacials, or will retreat in the future, exposed bedrock will rebound rapidly and flux meltwater out into the open ocean. Previous studies have suggested that this contribution to global mean sea level (GMSL) rise is small and occurs slowly. We challenge this notion using sea level predictions that incorporate both the outflux mechanism and complex three-dimensional viscoelastic mantle structure. In the case of the last interglacial, where the GMSL contribution from WAIS collapse is often cited as ~3 to 4 meters, the outflux mechanism contributes ~1 meter of additional GMSL change within ~1 thousand years of the collapse. Using a projection of future WAIS collapse, we also demonstrate that the outflux can substantially amplify GMSL rise estimates over the next century.

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Early Last Interglacial ocean warming drove substantial ice mass loss from Antarctica

Cited by 4 publications

References 9 publications

Sensitivity of the Antarctic ice sheets to the peak warming of Marine Isotope Stage 11

Sensitivity of the Antarctic ice sheets to the peak warming of Marine Isotope Stage 11

The Sensitivity of the Antarctic Ice Sheet to a Changing Climate: Past, Present, and Future

Rapid postglacial rebound amplifies global sea level rise following West Antarctic Ice Sheet collapse

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