Southern Ocean link between changes in atmospheric CO 2 levels and northern-hemisphere climate anomalies during the last two glacial periods
Past millennial-scale changes in atmospheric CO2 (CO2,atm) concentrations have often been attributed to variations in the overturning timescale of the ocean that result in changes in the marine carbon inventory. Yet, there remains a paucity of proxy evidence that documents changes in marine carbon s...
Published in: | Quaternary Science Reviews |
---|---|
Main Authors: | , , , , , |
Format: | Article in Journal/Newspaper |
Language: | unknown |
Published: |
Elsevier
2020
|
Subjects: | |
Online Access: | http://hdl.handle.net/1959.4/unsworks_79019 https://doi.org/10.1016/j.quascirev.2019.106067 |
id |
ftunswworks:oai:unsworks.library.unsw.edu.au:1959.4/unsworks_79019 |
---|---|
record_format |
openpolar |
spelling |
ftunswworks:oai:unsworks.library.unsw.edu.au:1959.4/unsworks_79019 2024-05-12T08:08:10+00:00 Southern Ocean link between changes in atmospheric CO 2 levels and northern-hemisphere climate anomalies during the last two glacial periods Gottschalk, J Skinner, LC Jaccard, SL Menviel, L Nehrbass-Ahles, C Waelbroeck, C 2020-02-15 http://hdl.handle.net/1959.4/unsworks_79019 https://doi.org/10.1016/j.quascirev.2019.106067 unknown Elsevier http://purl.org/au-research/grants/arc/FT180100606 http://hdl.handle.net/1959.4/unsworks_79019 https://doi.org/10.1016/j.quascirev.2019.106067 metadata only access http://purl.org/coar/access_right/c_14cb CC-BY-NC-ND https://creativecommons.org/licenses/by-nc-nd/4.0/ urn:ISSN:0277-3791 Quaternary Science Reviews, 230, 106067 13 Climate Action anzsrc-for: 04 Earth Sciences anzsrc-for: 21 History and Archaeology journal article http://purl.org/coar/resource_type/c_6501 2020 ftunswworks https://doi.org/10.1016/j.quascirev.2019.106067 2024-04-17T16:01:06Z Past millennial-scale changes in atmospheric CO2 (CO2,atm) concentrations have often been attributed to variations in the overturning timescale of the ocean that result in changes in the marine carbon inventory. Yet, there remains a paucity of proxy evidence that documents changes in marine carbon storage globally, and that links them to abrupt climate variability in the northern hemisphere associated with perturbations of the Atlantic Meridional Overturning Circulation (AMOC). The last two glacial periods were suggested to differ in the spatial extent of the AMOC and its sensitivity to perturbations. This provides an opportunity to compare the nature of marine carbon cycle-climate feedbacks between them. Here, we reconstruct variations in respired carbon storage (via oxygenation) and the AMOC “geometry” (via carbonate ion saturation) in the deep South Atlantic. We infer decreases in deep South Atlantic respired carbon levels at times of weakened AMOC and rising CO2,atm concentrations during both glacial periods. These findings suggest a consistent pattern of increased Southern Ocean convection and/or air-sea CO2 fluxes during northern-hemisphere stadials accompanying AMOC perturbations and promoting a rise in CO2,atm levels. We find that net ocean carbon loss, and hence the magnitude of CO2,atm rise, is largely determined by the stadial duration. North Atlantic climate anomalies therefore affect Southern Ocean carbon cycling in a consistent manner, through oceanic (e.g., ventilation seesaw) and/or atmospheric processes (e.g., Ekman pumping). Article in Journal/Newspaper North Atlantic Southern Ocean UNSW Sydney (The University of New South Wales): UNSWorks Southern Ocean Quaternary Science Reviews 230 106067 |
institution |
Open Polar |
collection |
UNSW Sydney (The University of New South Wales): UNSWorks |
op_collection_id |
ftunswworks |
language |
unknown |
topic |
13 Climate Action anzsrc-for: 04 Earth Sciences anzsrc-for: 21 History and Archaeology |
spellingShingle |
13 Climate Action anzsrc-for: 04 Earth Sciences anzsrc-for: 21 History and Archaeology Gottschalk, J Skinner, LC Jaccard, SL Menviel, L Nehrbass-Ahles, C Waelbroeck, C Southern Ocean link between changes in atmospheric CO 2 levels and northern-hemisphere climate anomalies during the last two glacial periods |
topic_facet |
13 Climate Action anzsrc-for: 04 Earth Sciences anzsrc-for: 21 History and Archaeology |
description |
Past millennial-scale changes in atmospheric CO2 (CO2,atm) concentrations have often been attributed to variations in the overturning timescale of the ocean that result in changes in the marine carbon inventory. Yet, there remains a paucity of proxy evidence that documents changes in marine carbon storage globally, and that links them to abrupt climate variability in the northern hemisphere associated with perturbations of the Atlantic Meridional Overturning Circulation (AMOC). The last two glacial periods were suggested to differ in the spatial extent of the AMOC and its sensitivity to perturbations. This provides an opportunity to compare the nature of marine carbon cycle-climate feedbacks between them. Here, we reconstruct variations in respired carbon storage (via oxygenation) and the AMOC “geometry” (via carbonate ion saturation) in the deep South Atlantic. We infer decreases in deep South Atlantic respired carbon levels at times of weakened AMOC and rising CO2,atm concentrations during both glacial periods. These findings suggest a consistent pattern of increased Southern Ocean convection and/or air-sea CO2 fluxes during northern-hemisphere stadials accompanying AMOC perturbations and promoting a rise in CO2,atm levels. We find that net ocean carbon loss, and hence the magnitude of CO2,atm rise, is largely determined by the stadial duration. North Atlantic climate anomalies therefore affect Southern Ocean carbon cycling in a consistent manner, through oceanic (e.g., ventilation seesaw) and/or atmospheric processes (e.g., Ekman pumping). |
format |
Article in Journal/Newspaper |
author |
Gottschalk, J Skinner, LC Jaccard, SL Menviel, L Nehrbass-Ahles, C Waelbroeck, C |
author_facet |
Gottschalk, J Skinner, LC Jaccard, SL Menviel, L Nehrbass-Ahles, C Waelbroeck, C |
author_sort |
Gottschalk, J |
title |
Southern Ocean link between changes in atmospheric CO 2 levels and northern-hemisphere climate anomalies during the last two glacial periods |
title_short |
Southern Ocean link between changes in atmospheric CO 2 levels and northern-hemisphere climate anomalies during the last two glacial periods |
title_full |
Southern Ocean link between changes in atmospheric CO 2 levels and northern-hemisphere climate anomalies during the last two glacial periods |
title_fullStr |
Southern Ocean link between changes in atmospheric CO 2 levels and northern-hemisphere climate anomalies during the last two glacial periods |
title_full_unstemmed |
Southern Ocean link between changes in atmospheric CO 2 levels and northern-hemisphere climate anomalies during the last two glacial periods |
title_sort |
southern ocean link between changes in atmospheric co 2 levels and northern-hemisphere climate anomalies during the last two glacial periods |
publisher |
Elsevier |
publishDate |
2020 |
url |
http://hdl.handle.net/1959.4/unsworks_79019 https://doi.org/10.1016/j.quascirev.2019.106067 |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
North Atlantic Southern Ocean |
genre_facet |
North Atlantic Southern Ocean |
op_source |
urn:ISSN:0277-3791 Quaternary Science Reviews, 230, 106067 |
op_relation |
http://purl.org/au-research/grants/arc/FT180100606 http://hdl.handle.net/1959.4/unsworks_79019 https://doi.org/10.1016/j.quascirev.2019.106067 |
op_rights |
metadata only access http://purl.org/coar/access_right/c_14cb CC-BY-NC-ND https://creativecommons.org/licenses/by-nc-nd/4.0/ |
op_doi |
https://doi.org/10.1016/j.quascirev.2019.106067 |
container_title |
Quaternary Science Reviews |
container_volume |
230 |
container_start_page |
106067 |
_version_ |
1798851086465892352 |