Atmospheric and oceanic impacts of Antarctic glaciation across the Eocene–Oligocene transition

The glaciation of Antarctica at the Eocene–Oligocene transition (approx. 34 million years ago) was a major shift in the Earth’s climate system, but the mechanisms that caused the glaciation, and its effects, remain highly debated. A number of recent studies have used coupled atmosphere–ocean climate...

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Published in:Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
Main Authors: Kennedy, A. T., Farnsworth, A., Lunt, D. J., Lear, C. H., Markwick, P. J.
Format: Article in Journal/Newspaper
Language:English
Published: The Royal Society 2015
Subjects:
Online Access:http://dx.doi.org/10.1098/rsta.2014.0419
https://royalsocietypublishing.org/doi/pdf/10.1098/rsta.2014.0419
https://royalsocietypublishing.org/doi/full-xml/10.1098/rsta.2014.0419
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spelling crroyalsociety:10.1098/rsta.2014.0419 2024-09-15T17:41:00+00:00 Atmospheric and oceanic impacts of Antarctic glaciation across the Eocene–Oligocene transition Kennedy, A. T. Farnsworth, A. Lunt, D. J. Lear, C. H. Markwick, P. J. 2015 http://dx.doi.org/10.1098/rsta.2014.0419 https://royalsocietypublishing.org/doi/pdf/10.1098/rsta.2014.0419 https://royalsocietypublishing.org/doi/full-xml/10.1098/rsta.2014.0419 en eng The Royal Society https://royalsociety.org/journals/ethics-policies/data-sharing-mining/ Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences volume 373, issue 2054, page 20140419 ISSN 1364-503X 1471-2962 journal-article 2015 crroyalsociety https://doi.org/10.1098/rsta.2014.0419 2024-07-29T04:23:20Z The glaciation of Antarctica at the Eocene–Oligocene transition (approx. 34 million years ago) was a major shift in the Earth’s climate system, but the mechanisms that caused the glaciation, and its effects, remain highly debated. A number of recent studies have used coupled atmosphere–ocean climate models to assess the climatic effects of Antarctic glacial inception, with often contrasting results. Here, using the HadCM3L model, we show that the global atmosphere and ocean response to growth of the Antarctic ice sheet is sensitive to subtle variations in palaeogeography, using two reconstructions representing Eocene and Oligocene geological stages. The earlier stage (Eocene; Priabonian), which has a relatively constricted Tasman Seaway, shows a major increase in sea surface temperature over the Pacific sector of the Southern Ocean in response to the ice sheet. This response does not occur for the later stage (Oligocene; Rupelian), which has a more open Tasman Seaway. This difference in temperature response is attributed to reorganization of ocean currents between the stages. Following ice sheet expansion in the earlier stage, the large Ross Sea gyre circulation decreases in size. Stronger zonal flow through the Tasman Seaway allows salinities to increase in the Ross Sea, deep-water formation initiates and multiple feedbacks then occur amplifying the temperature response. This is potentially a model-dependent result, but it highlights the sensitive nature of model simulations to subtle variations in palaeogeography, and highlights the need for coupled ice sheet–climate simulations to properly represent and investigate feedback processes acting on these time scales. Article in Journal/Newspaper Antarc* Antarctic Antarctica Ice Sheet Ross Sea Southern Ocean The Royal Society Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 373 2054 20140419
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collection The Royal Society
op_collection_id crroyalsociety
language English
description The glaciation of Antarctica at the Eocene–Oligocene transition (approx. 34 million years ago) was a major shift in the Earth’s climate system, but the mechanisms that caused the glaciation, and its effects, remain highly debated. A number of recent studies have used coupled atmosphere–ocean climate models to assess the climatic effects of Antarctic glacial inception, with often contrasting results. Here, using the HadCM3L model, we show that the global atmosphere and ocean response to growth of the Antarctic ice sheet is sensitive to subtle variations in palaeogeography, using two reconstructions representing Eocene and Oligocene geological stages. The earlier stage (Eocene; Priabonian), which has a relatively constricted Tasman Seaway, shows a major increase in sea surface temperature over the Pacific sector of the Southern Ocean in response to the ice sheet. This response does not occur for the later stage (Oligocene; Rupelian), which has a more open Tasman Seaway. This difference in temperature response is attributed to reorganization of ocean currents between the stages. Following ice sheet expansion in the earlier stage, the large Ross Sea gyre circulation decreases in size. Stronger zonal flow through the Tasman Seaway allows salinities to increase in the Ross Sea, deep-water formation initiates and multiple feedbacks then occur amplifying the temperature response. This is potentially a model-dependent result, but it highlights the sensitive nature of model simulations to subtle variations in palaeogeography, and highlights the need for coupled ice sheet–climate simulations to properly represent and investigate feedback processes acting on these time scales.
format Article in Journal/Newspaper
author Kennedy, A. T.
Farnsworth, A.
Lunt, D. J.
Lear, C. H.
Markwick, P. J.
spellingShingle Kennedy, A. T.
Farnsworth, A.
Lunt, D. J.
Lear, C. H.
Markwick, P. J.
Atmospheric and oceanic impacts of Antarctic glaciation across the Eocene–Oligocene transition
author_facet Kennedy, A. T.
Farnsworth, A.
Lunt, D. J.
Lear, C. H.
Markwick, P. J.
author_sort Kennedy, A. T.
title Atmospheric and oceanic impacts of Antarctic glaciation across the Eocene–Oligocene transition
title_short Atmospheric and oceanic impacts of Antarctic glaciation across the Eocene–Oligocene transition
title_full Atmospheric and oceanic impacts of Antarctic glaciation across the Eocene–Oligocene transition
title_fullStr Atmospheric and oceanic impacts of Antarctic glaciation across the Eocene–Oligocene transition
title_full_unstemmed Atmospheric and oceanic impacts of Antarctic glaciation across the Eocene–Oligocene transition
title_sort atmospheric and oceanic impacts of antarctic glaciation across the eocene–oligocene transition
publisher The Royal Society
publishDate 2015
url http://dx.doi.org/10.1098/rsta.2014.0419
https://royalsocietypublishing.org/doi/pdf/10.1098/rsta.2014.0419
https://royalsocietypublishing.org/doi/full-xml/10.1098/rsta.2014.0419
genre Antarc*
Antarctic
Antarctica
Ice Sheet
Ross Sea
Southern Ocean
genre_facet Antarc*
Antarctic
Antarctica
Ice Sheet
Ross Sea
Southern Ocean
op_source Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
volume 373, issue 2054, page 20140419
ISSN 1364-503X 1471-2962
op_rights https://royalsociety.org/journals/ethics-policies/data-sharing-mining/
op_doi https://doi.org/10.1098/rsta.2014.0419
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