Role of CO2 and Southern Ocean winds in glacial abrupt climate change
The study of Greenland ice cores revealed two decades ago the abrupt character of glacial millennial-scale climate variability. Several triggering mechanisms have been proposed and confronted against growing proxy-data evidence. Although the implication of North Atlantic deep water (NADW) formation...
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fttriple:oai:gotriple.eu:oai:doaj.org/article:c6ffc43e2a3d41cc808c16037996e83c 2023-05-15T16:28:20+02:00 Role of CO2 and Southern Ocean winds in glacial abrupt climate change M. Montoya J. Álvarez-Solas R. Banderas 2012-06-01 https://doi.org/10.5194/cp-8-1011-2012 http://www.clim-past.net/8/1011/2012/cp-8-1011-2012.pdf https://doaj.org/article/c6ffc43e2a3d41cc808c16037996e83c en eng Copernicus Publications doi:10.5194/cp-8-1011-2012 1814-9324 1814-9332 http://www.clim-past.net/8/1011/2012/cp-8-1011-2012.pdf https://doaj.org/article/c6ffc43e2a3d41cc808c16037996e83c undefined Climate of the Past, Vol 8, Iss 3, Pp 1011-1021 (2012) envir geo Journal Article https://vocabularies.coar-repositories.org/resource_types/c_6501/ 2012 fttriple https://doi.org/10.5194/cp-8-1011-2012 2023-01-22T19:05:35Z The study of Greenland ice cores revealed two decades ago the abrupt character of glacial millennial-scale climate variability. Several triggering mechanisms have been proposed and confronted against growing proxy-data evidence. Although the implication of North Atlantic deep water (NADW) formation reorganisations in glacial abrupt climate change seems robust nowadays, the final cause of these reorganisations remains unclear. Here, the role of CO2 and Southern Ocean winds is investigated using a coupled model of intermediate complexity in an experimental setup designed such that the climate system resides close to a threshold found in previous studies. An initial abrupt surface air temperature (SAT) increase over the North Atlantic by 4 K in less than a decade, followed by a more gradual warming greater than 10 K on centennial timescales, is simulated in response to increasing atmospheric CO2 levels and/or enhancing southern westerlies. The simulated peak warming shows a similar pattern and amplitude over Greenland as registered in ice core records of Dansgaard-Oeschger (D/O) events. This is accompanied by a strong Atlantic meridional overturning circulation (AMOC) intensification. The AMOC strengthening is found to be caused by a northward shift of NADW formation sites into the Nordic Seas as a result of a northward retreat of the sea-ice front in response to higher temperatures. This leads to enhanced heat loss to the atmosphere as well as reduced freshwater fluxes via reduced sea-ice import into the region. In this way, a new mechanism that is consistent with proxy data is identified by which abrupt climate change can be promoted. Article in Journal/Newspaper Greenland Greenland ice cores ice core NADW Nordic Seas North Atlantic Deep Water North Atlantic Sea ice Southern Ocean Unknown Greenland Southern Ocean Climate of the Past 8 3 1011 1021 |
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envir geo M. Montoya J. Álvarez-Solas R. Banderas Role of CO2 and Southern Ocean winds in glacial abrupt climate change |
topic_facet |
envir geo |
description |
The study of Greenland ice cores revealed two decades ago the abrupt character of glacial millennial-scale climate variability. Several triggering mechanisms have been proposed and confronted against growing proxy-data evidence. Although the implication of North Atlantic deep water (NADW) formation reorganisations in glacial abrupt climate change seems robust nowadays, the final cause of these reorganisations remains unclear. Here, the role of CO2 and Southern Ocean winds is investigated using a coupled model of intermediate complexity in an experimental setup designed such that the climate system resides close to a threshold found in previous studies. An initial abrupt surface air temperature (SAT) increase over the North Atlantic by 4 K in less than a decade, followed by a more gradual warming greater than 10 K on centennial timescales, is simulated in response to increasing atmospheric CO2 levels and/or enhancing southern westerlies. The simulated peak warming shows a similar pattern and amplitude over Greenland as registered in ice core records of Dansgaard-Oeschger (D/O) events. This is accompanied by a strong Atlantic meridional overturning circulation (AMOC) intensification. The AMOC strengthening is found to be caused by a northward shift of NADW formation sites into the Nordic Seas as a result of a northward retreat of the sea-ice front in response to higher temperatures. This leads to enhanced heat loss to the atmosphere as well as reduced freshwater fluxes via reduced sea-ice import into the region. In this way, a new mechanism that is consistent with proxy data is identified by which abrupt climate change can be promoted. |
format |
Article in Journal/Newspaper |
author |
M. Montoya J. Álvarez-Solas R. Banderas |
author_facet |
M. Montoya J. Álvarez-Solas R. Banderas |
author_sort |
M. Montoya |
title |
Role of CO2 and Southern Ocean winds in glacial abrupt climate change |
title_short |
Role of CO2 and Southern Ocean winds in glacial abrupt climate change |
title_full |
Role of CO2 and Southern Ocean winds in glacial abrupt climate change |
title_fullStr |
Role of CO2 and Southern Ocean winds in glacial abrupt climate change |
title_full_unstemmed |
Role of CO2 and Southern Ocean winds in glacial abrupt climate change |
title_sort |
role of co2 and southern ocean winds in glacial abrupt climate change |
publisher |
Copernicus Publications |
publishDate |
2012 |
url |
https://doi.org/10.5194/cp-8-1011-2012 http://www.clim-past.net/8/1011/2012/cp-8-1011-2012.pdf https://doaj.org/article/c6ffc43e2a3d41cc808c16037996e83c |
geographic |
Greenland Southern Ocean |
geographic_facet |
Greenland Southern Ocean |
genre |
Greenland Greenland ice cores ice core NADW Nordic Seas North Atlantic Deep Water North Atlantic Sea ice Southern Ocean |
genre_facet |
Greenland Greenland ice cores ice core NADW Nordic Seas North Atlantic Deep Water North Atlantic Sea ice Southern Ocean |
op_source |
Climate of the Past, Vol 8, Iss 3, Pp 1011-1021 (2012) |
op_relation |
doi:10.5194/cp-8-1011-2012 1814-9324 1814-9332 http://www.clim-past.net/8/1011/2012/cp-8-1011-2012.pdf https://doaj.org/article/c6ffc43e2a3d41cc808c16037996e83c |
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undefined |
op_doi |
https://doi.org/10.5194/cp-8-1011-2012 |
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Climate of the Past |
container_volume |
8 |
container_issue |
3 |
container_start_page |
1011 |
op_container_end_page |
1021 |
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1766017973201403904 |