Antarctic climate and ice-sheet configuration during the early Pliocene interglacial at 4.23 Ma
The geometry of Antarctic ice sheets during warm periods of the geological past is difficult to determine from geological evidence, but is important to know because such reconstructions enable a more complete understanding of how the ice-sheet system responds to changes in climate. Here we investiga...
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ftcopernicus:oai:publications.copernicus.org:cp55969 2023-05-15T13:54:27+02:00 Antarctic climate and ice-sheet configuration during the early Pliocene interglacial at 4.23 Ma Golledge, Nicholas R. Thomas, Zoë A. Levy, Richard H. Gasson, Edward G. W. Naish, Timothy R. McKay, Robert M. Kowalewski, Douglas E. Fogwill, Christopher J. 2018-09-27 application/pdf https://doi.org/10.5194/cp-13-959-2017 https://cp.copernicus.org/articles/13/959/2017/ eng eng doi:10.5194/cp-13-959-2017 https://cp.copernicus.org/articles/13/959/2017/ eISSN: 1814-9332 Text 2018 ftcopernicus https://doi.org/10.5194/cp-13-959-2017 2020-07-20T16:23:38Z The geometry of Antarctic ice sheets during warm periods of the geological past is difficult to determine from geological evidence, but is important to know because such reconstructions enable a more complete understanding of how the ice-sheet system responds to changes in climate. Here we investigate how Antarctica evolved under orbital and greenhouse gas conditions representative of an interglacial in the early Pliocene at 4.23 Ma, when Southern Hemisphere insolation reached a maximum. Using offline-coupled climate and ice-sheet models, together with a new synthesis of high-latitude palaeoenvironmental proxy data to define a likely climate envelope, we simulate a range of ice-sheet geometries and calculate their likely contribution to sea level. In addition, we use these simulations to investigate the processes by which the West and East Antarctic ice sheets respond to environmental forcings and the timescales over which these behaviours manifest. We conclude that the Antarctic ice sheet contributed 8.6 ± 2.8 m to global sea level at this time, under an atmospheric CO 2 concentration identical to present (400 ppm). Warmer-than-present ocean temperatures led to the collapse of West Antarctica over centuries, whereas higher air temperatures initiated surface melting in parts of East Antarctica that over one to two millennia led to lowering of the ice-sheet surface, flotation of grounded margins in some areas, and retreat of the ice sheet into the Wilkes Subglacial Basin. The results show that regional variations in climate, ice-sheet geometry, and topography produce long-term sea-level contributions that are non-linear with respect to the applied forcings, and which under certain conditions exhibit threshold behaviour associated with behavioural tipping points. Text Antarc* Antarctic Antarctica East Antarctica Ice Sheet West Antarctica Copernicus Publications: E-Journals Antarctic East Antarctica The Antarctic West Antarctica Wilkes Subglacial Basin ENVELOPE(145.000,145.000,-75.000,-75.000) Climate of the Past 13 7 959 975 |
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Open Polar |
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Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
The geometry of Antarctic ice sheets during warm periods of the geological past is difficult to determine from geological evidence, but is important to know because such reconstructions enable a more complete understanding of how the ice-sheet system responds to changes in climate. Here we investigate how Antarctica evolved under orbital and greenhouse gas conditions representative of an interglacial in the early Pliocene at 4.23 Ma, when Southern Hemisphere insolation reached a maximum. Using offline-coupled climate and ice-sheet models, together with a new synthesis of high-latitude palaeoenvironmental proxy data to define a likely climate envelope, we simulate a range of ice-sheet geometries and calculate their likely contribution to sea level. In addition, we use these simulations to investigate the processes by which the West and East Antarctic ice sheets respond to environmental forcings and the timescales over which these behaviours manifest. We conclude that the Antarctic ice sheet contributed 8.6 ± 2.8 m to global sea level at this time, under an atmospheric CO 2 concentration identical to present (400 ppm). Warmer-than-present ocean temperatures led to the collapse of West Antarctica over centuries, whereas higher air temperatures initiated surface melting in parts of East Antarctica that over one to two millennia led to lowering of the ice-sheet surface, flotation of grounded margins in some areas, and retreat of the ice sheet into the Wilkes Subglacial Basin. The results show that regional variations in climate, ice-sheet geometry, and topography produce long-term sea-level contributions that are non-linear with respect to the applied forcings, and which under certain conditions exhibit threshold behaviour associated with behavioural tipping points. |
format |
Text |
author |
Golledge, Nicholas R. Thomas, Zoë A. Levy, Richard H. Gasson, Edward G. W. Naish, Timothy R. McKay, Robert M. Kowalewski, Douglas E. Fogwill, Christopher J. |
spellingShingle |
Golledge, Nicholas R. Thomas, Zoë A. Levy, Richard H. Gasson, Edward G. W. Naish, Timothy R. McKay, Robert M. Kowalewski, Douglas E. Fogwill, Christopher J. Antarctic climate and ice-sheet configuration during the early Pliocene interglacial at 4.23 Ma |
author_facet |
Golledge, Nicholas R. Thomas, Zoë A. Levy, Richard H. Gasson, Edward G. W. Naish, Timothy R. McKay, Robert M. Kowalewski, Douglas E. Fogwill, Christopher J. |
author_sort |
Golledge, Nicholas R. |
title |
Antarctic climate and ice-sheet configuration during the early Pliocene interglacial at 4.23 Ma |
title_short |
Antarctic climate and ice-sheet configuration during the early Pliocene interglacial at 4.23 Ma |
title_full |
Antarctic climate and ice-sheet configuration during the early Pliocene interglacial at 4.23 Ma |
title_fullStr |
Antarctic climate and ice-sheet configuration during the early Pliocene interglacial at 4.23 Ma |
title_full_unstemmed |
Antarctic climate and ice-sheet configuration during the early Pliocene interglacial at 4.23 Ma |
title_sort |
antarctic climate and ice-sheet configuration during the early pliocene interglacial at 4.23 ma |
publishDate |
2018 |
url |
https://doi.org/10.5194/cp-13-959-2017 https://cp.copernicus.org/articles/13/959/2017/ |
long_lat |
ENVELOPE(145.000,145.000,-75.000,-75.000) |
geographic |
Antarctic East Antarctica The Antarctic West Antarctica Wilkes Subglacial Basin |
geographic_facet |
Antarctic East Antarctica The Antarctic West Antarctica Wilkes Subglacial Basin |
genre |
Antarc* Antarctic Antarctica East Antarctica Ice Sheet West Antarctica |
genre_facet |
Antarc* Antarctic Antarctica East Antarctica Ice Sheet West Antarctica |
op_source |
eISSN: 1814-9332 |
op_relation |
doi:10.5194/cp-13-959-2017 https://cp.copernicus.org/articles/13/959/2017/ |
op_doi |
https://doi.org/10.5194/cp-13-959-2017 |
container_title |
Climate of the Past |
container_volume |
13 |
container_issue |
7 |
container_start_page |
959 |
op_container_end_page |
975 |
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1766260321242054656 |