Timing and magnitude of Southern Ocean sea ice/carbon cycle feedbacks
The Southern Ocean (SO) played a prominent role in the exchange of carbon between ocean and atmosphere on glacial timescales through its regulation of deep ocean ventilation. Previous studies indicated that SO sea ice could dynamically link several processes of carbon sequestration, but these studie...
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ftpubmed:oai:pubmedcentral.nih.gov:7060729 2023-05-15T14:04:13+02:00 Timing and magnitude of Southern Ocean sea ice/carbon cycle feedbacks Stein, Karl Timmermann, Axel Kwon, Eun Young Friedrich, Tobias 2020-03-03 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7060729/ http://www.ncbi.nlm.nih.gov/pubmed/32071218 https://doi.org/10.1073/pnas.1908670117 en eng National Academy of Sciences http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7060729/ http://www.ncbi.nlm.nih.gov/pubmed/32071218 http://dx.doi.org/10.1073/pnas.1908670117 https://www.pnas.org/site/aboutpnas/licenses.xhtmlPublished under the PNAS license (https://www.pnas.org/site/aboutpnas/licenses.xhtml) . Proc Natl Acad Sci U S A Physical Sciences Text 2020 ftpubmed https://doi.org/10.1073/pnas.1908670117 2020-08-23T00:16:28Z The Southern Ocean (SO) played a prominent role in the exchange of carbon between ocean and atmosphere on glacial timescales through its regulation of deep ocean ventilation. Previous studies indicated that SO sea ice could dynamically link several processes of carbon sequestration, but these studies relied on models with simplified ocean and sea ice dynamics or snapshot simulations with general circulation models. Here, we use a transient run of an intermediate complexity climate model, covering the past eight glacial cycles, to investigate the orbital-scale dynamics of deep ocean ventilation changes due to SO sea ice. Cold climates increase sea ice cover, sea ice export, and Antarctic Bottom Water formation, which are accompanied by increased SO upwelling, stronger poleward export of Circumpolar Deep Water, and a reduction of the atmospheric exposure time of surface waters by a factor of 10. Moreover, increased brine formation around Antarctica enhances deep ocean stratification, which could act to decrease vertical mixing by a factor of four compared with the current climate. Sensitivity tests with a steady-state carbon cycle model indicate that the two mechanisms combined can reduce atmospheric carbon by 40 ppm, with ocean stratification acting early within a glacial cycle to amplify the carbon cycle response. Text Antarc* Antarctic Antarctica Sea ice Southern Ocean PubMed Central (PMC) Antarctic Southern Ocean Proceedings of the National Academy of Sciences 117 9 4498 4504 |
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Physical Sciences Stein, Karl Timmermann, Axel Kwon, Eun Young Friedrich, Tobias Timing and magnitude of Southern Ocean sea ice/carbon cycle feedbacks |
topic_facet |
Physical Sciences |
description |
The Southern Ocean (SO) played a prominent role in the exchange of carbon between ocean and atmosphere on glacial timescales through its regulation of deep ocean ventilation. Previous studies indicated that SO sea ice could dynamically link several processes of carbon sequestration, but these studies relied on models with simplified ocean and sea ice dynamics or snapshot simulations with general circulation models. Here, we use a transient run of an intermediate complexity climate model, covering the past eight glacial cycles, to investigate the orbital-scale dynamics of deep ocean ventilation changes due to SO sea ice. Cold climates increase sea ice cover, sea ice export, and Antarctic Bottom Water formation, which are accompanied by increased SO upwelling, stronger poleward export of Circumpolar Deep Water, and a reduction of the atmospheric exposure time of surface waters by a factor of 10. Moreover, increased brine formation around Antarctica enhances deep ocean stratification, which could act to decrease vertical mixing by a factor of four compared with the current climate. Sensitivity tests with a steady-state carbon cycle model indicate that the two mechanisms combined can reduce atmospheric carbon by 40 ppm, with ocean stratification acting early within a glacial cycle to amplify the carbon cycle response. |
format |
Text |
author |
Stein, Karl Timmermann, Axel Kwon, Eun Young Friedrich, Tobias |
author_facet |
Stein, Karl Timmermann, Axel Kwon, Eun Young Friedrich, Tobias |
author_sort |
Stein, Karl |
title |
Timing and magnitude of Southern Ocean sea ice/carbon cycle feedbacks |
title_short |
Timing and magnitude of Southern Ocean sea ice/carbon cycle feedbacks |
title_full |
Timing and magnitude of Southern Ocean sea ice/carbon cycle feedbacks |
title_fullStr |
Timing and magnitude of Southern Ocean sea ice/carbon cycle feedbacks |
title_full_unstemmed |
Timing and magnitude of Southern Ocean sea ice/carbon cycle feedbacks |
title_sort |
timing and magnitude of southern ocean sea ice/carbon cycle feedbacks |
publisher |
National Academy of Sciences |
publishDate |
2020 |
url |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7060729/ http://www.ncbi.nlm.nih.gov/pubmed/32071218 https://doi.org/10.1073/pnas.1908670117 |
geographic |
Antarctic Southern Ocean |
geographic_facet |
Antarctic Southern Ocean |
genre |
Antarc* Antarctic Antarctica Sea ice Southern Ocean |
genre_facet |
Antarc* Antarctic Antarctica Sea ice Southern Ocean |
op_source |
Proc Natl Acad Sci U S A |
op_relation |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7060729/ http://www.ncbi.nlm.nih.gov/pubmed/32071218 http://dx.doi.org/10.1073/pnas.1908670117 |
op_rights |
https://www.pnas.org/site/aboutpnas/licenses.xhtmlPublished under the PNAS license (https://www.pnas.org/site/aboutpnas/licenses.xhtml) . |
op_doi |
https://doi.org/10.1073/pnas.1908670117 |
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Proceedings of the National Academy of Sciences |
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117 |
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9 |
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4498 |
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4504 |
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1766275241647013888 |