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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ftdoajarticles:oai:doaj.org/article:3c91d2d607b3442a9f2784b96a743b0f 2023-05-15T13:54:36+02:00 Antarctic climate and ice-sheet configuration during the early Pliocene interglacial at 4.23 Ma N. R. Golledge Z. A. Thomas R. H. Levy E. G. W. Gasson T. R. Naish R. M. McKay D. E. Kowalewski C. J. Fogwill 2017-07-01T00:00:00Z https://doi.org/10.5194/cp-13-959-2017 https://doaj.org/article/3c91d2d607b3442a9f2784b96a743b0f EN eng Copernicus Publications https://www.clim-past.net/13/959/2017/cp-13-959-2017.pdf https://doaj.org/toc/1814-9324 https://doaj.org/toc/1814-9332 doi:10.5194/cp-13-959-2017 1814-9324 1814-9332 https://doaj.org/article/3c91d2d607b3442a9f2784b96a743b0f Climate of the Past, Vol 13, Pp 959-975 (2017) Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 article 2017 ftdoajarticles https://doi.org/10.5194/cp-13-959-2017 2022-12-31T14:58:34Z 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. Article in Journal/Newspaper Antarc* Antarctic Antarctica East Antarctica Ice Sheet West Antarctica Directory of Open Access Journals: DOAJ Articles Antarctic The Antarctic East Antarctica West Antarctica Wilkes Subglacial Basin ENVELOPE(145.000,145.000,-75.000,-75.000) Climate of the Past 13 7 959 975 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 |
spellingShingle |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 N. R. Golledge Z. A. Thomas R. H. Levy E. G. W. Gasson T. R. Naish R. M. McKay D. E. Kowalewski C. J. Fogwill Antarctic climate and ice-sheet configuration during the early Pliocene interglacial at 4.23 Ma |
topic_facet |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 |
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 |
Article in Journal/Newspaper |
author |
N. R. Golledge Z. A. Thomas R. H. Levy E. G. W. Gasson T. R. Naish R. M. McKay D. E. Kowalewski C. J. Fogwill |
author_facet |
N. R. Golledge Z. A. Thomas R. H. Levy E. G. W. Gasson T. R. Naish R. M. McKay D. E. Kowalewski C. J. Fogwill |
author_sort |
N. R. Golledge |
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 |
publisher |
Copernicus Publications |
publishDate |
2017 |
url |
https://doi.org/10.5194/cp-13-959-2017 https://doaj.org/article/3c91d2d607b3442a9f2784b96a743b0f |
long_lat |
ENVELOPE(145.000,145.000,-75.000,-75.000) |
geographic |
Antarctic The Antarctic East Antarctica West Antarctica Wilkes Subglacial Basin |
geographic_facet |
Antarctic The Antarctic East Antarctica 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 |
Climate of the Past, Vol 13, Pp 959-975 (2017) |
op_relation |
https://www.clim-past.net/13/959/2017/cp-13-959-2017.pdf https://doaj.org/toc/1814-9324 https://doaj.org/toc/1814-9332 doi:10.5194/cp-13-959-2017 1814-9324 1814-9332 https://doaj.org/article/3c91d2d607b3442a9f2784b96a743b0f |
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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1766260594951847936 |