Dynamic behaviour of the East Antarctic ice sheet during Pliocene warmth

Cook, C.; Flierdt, Tina van de; Williams, T.; Hemming, S. R.; Iwai, Masao; Kobayashi, Munemasa; Jiménez‐Espejo, Francisco J.; Escutia, Carlota; González, Javier; Khim, Boo‐Keun; McKay, Robert; Passchier, Sandra; Bohaty, Steven M; Riesselman, C. R.; Tauxe, Lisa; Sugisaki, Saiko; Galindo, Alberto; Patterson, Molly O.; Sangiorgi, Francesca; Pierce, E. L.; Brinkhuis, Henk; Klaus, A.; Fehr, A.; Bendle, James; Bijl, Peter K.; Carr, Stephanie; Dunbar, Robert B.; Flores, José-Abel; Hayden, T. G.; Katsuki, Kota; Kong, Gee-Soo; Nakai, Mutsumi; Olney, M.; Pekar, Stephen F.; Pross, Jörg; Röhl, Ursula; Sakai, Toshiro; Shrivastava, Prakash K.; Stickley, Catherine E; Tuo, Shouting; Welsh, Kevin; Yamane, Masako

doi:10.1038/ngeo1889

Cited by 276 publications

(317 citation statements)

References 28 publications

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“…We investigate how this uncertainty affects simulations of mid-Pliocene warm period ice sheet dynamics, as this is a period with atmospheric CO 2 concentrations similar to the present (400 ppm) [Seki et al, 2010] with evidence for large-scale retreat of both the West and East Antarctic ice sheets Cook et al, 2013;Raymo et al, 2011]. Although we explore ice sheet sensitivity to bedrock elevation uncertainty for a mid-Pliocene climate forcing, these uncertainties are also relevant to simulations of future ice sheet dynamics for a projected warmer climate [Collins et al, 2013].…”

Section: Introductionmentioning

confidence: 99%

Antarctic bedrock topography uncertainty and ice sheet stability

Gasson

DeConto

Pollard

2015

Geophysical Research Letters

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Antarctic bedrock elevation estimates have uncertainties exceeding 1 km in certain regions. Bedrock elevation, particularly where the bedrock is below sea level and bordering the ocean, can have a large impact on ice sheet stability. We investigate how present‐day bedrock elevation uncertainty affects ice sheet model simulations for a generic past warm period based on the mid‐Pliocene, although these uncertainties are also relevant to present‐day and future ice sheet stability. We perform an ensemble of simulations with random topographic noise added with various length scales and with amplitudes tuned to the uncertainty of the Bedmap2 data set. Total Antarctic ice sheet retreat in these simulations varies between 12.6 and 17.9 m equivalent sea level rise after 3 kyrs of warm climate forcing. This study highlights the sensitivity of ice sheet models to existing uncertainties in bedrock elevation and the ongoing need for new data acquisition.

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Section: Introductionmentioning

confidence: 99%

Antarctic bedrock topography uncertainty and ice sheet stability

Gasson

DeConto

Pollard

2015

Geophysical Research Letters

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“…2). Isotopic Nd and Sr provenance indicators suggest that the terrigenous components in these diatomrich/bearing muds are associated with periods of glacial retreat of the ice margin back into the Wilkes Land Subglacial Basin during the Early Pliocene 17 . The Antarctic ice sheet loses the majority of its mass via iceberg calving and sub-ice-shelf melting 18 , which are intimately linked because enhanced ice-shelf melt leads to reduced buttressing, that in turn acts to enhance the flow of glacial tributaries, ultimately enhancing iceberg discharge 19 .…”

mentioning

confidence: 99%

“…Geologic records 7,9,17 and model simulations 8 of past warm climates highlight the sensitivity of the marine-based portions of the Antarctic ice sheets to ocean warming. However, the mechanism by which the coastal ocean warms and destabilizes marine grounding lines, particularly in response to obliquity forcing, remains elusive.…”

mentioning

confidence: 99%

Orbital forcing of the East Antarctic ice sheet during the Pliocene and Early Pleistocene

et al. 2014

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The Pliocene and Early Pleistocene, between 5.3 and 0.8 million years ago, span a transition from a global climate state that was 2-3• C warmer than present with limited ice sheets in the Northern Hemisphere to one that was characterized by continental-scale glaciations at both poles. Growth and decay of these ice sheets was paced by variations in the Earth's orbit around the Sun. However, the nature of the influence of orbital forcing on the ice sheets is unclear, particularly in light of the absence of a strong 20,000-year precession signal in geologic records of global ice volume and sea level. Here we present a record of the rate of accumulation of iceberg-rafted debris o shore from the East Antarctic ice sheet, adjacent to the Wilkes Subglacial Basin, between 4.3 and 2.2 million years ago. We infer that maximum iceberg debris accumulation is associated with the enhanced calving of icebergs during ice-sheet margin retreat. In the warmer part of the record, between 4.3 and 3.5 million years ago, spectral analyses show a dominant periodicity of about 40,000 years. Subsequently, the powers of the 100,000-year and 20,000-year signals strengthen. We suggest that, as the Southern Ocean cooled between 3.5 and 2.5 million years ago, the development of a perennial sea-ice field limited the oceanic forcing of the ice sheet. After this threshold was crossed, substantial retreat of the East Antarctic ice sheet occurred only during austral summer insolation maxima, as controlled by the precession cycle.

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“…Instead, the sea-floor sediments revealed that the ice sheet waxed and waned many times between 5.3 million and 3.3 million years ago 7 -an epoch called the Pliocene, when air temperatures were up to 2 °C higher than today. "We got a clear signal every time it was warm, suggesting that the ice sheet was sensitive to climate warming, " says van de Flierdt.…”

Section: Troubled Pastmentioning

confidence: 99%

Antarctica’s sleeping ice giant could wake soon

Qiu¹

2017

Nature

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Dynamic behaviour of the East Antarctic ice sheet during Pliocene warmth

Cited by 276 publications

References 28 publications

Antarctic bedrock topography uncertainty and ice sheet stability

Antarctic bedrock topography uncertainty and ice sheet stability

Orbital forcing of the East Antarctic ice sheet during the Pliocene and Early Pleistocene

Antarctica’s sleeping ice giant could wake soon

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