Response of the carbon cycle in an intermediate complexity model to the different climate configurations of the last nine interglacials
Atmospheric CO 2 levels during interglacials prior to the Mid-Brunhes Event (MBE, ∼ 430 ka BP ) were around 40 ppm lower than after the MBE. The reasons for this difference remain unclear. A recent hypothesis proposed that changes in oceanic circulation, in response to different external forcings be...
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ftcopernicus:oai:publications.copernicus.org:cp55600 2023-05-15T16:37:47+02:00 Response of the carbon cycle in an intermediate complexity model to the different climate configurations of the last nine interglacials Bouttes, Nathaelle Swingedouw, Didier Roche, Didier M. Sanchez-Goni, Maria F. Crosta, Xavier 2019-04-10 application/pdf https://doi.org/10.5194/cp-14-239-2018 https://cp.copernicus.org/articles/14/239/2018/ eng eng doi:10.5194/cp-14-239-2018 https://cp.copernicus.org/articles/14/239/2018/ eISSN: 1814-9332 Text 2019 ftcopernicus https://doi.org/10.5194/cp-14-239-2018 2020-07-20T16:23:23Z Atmospheric CO 2 levels during interglacials prior to the Mid-Brunhes Event (MBE, ∼ 430 ka BP ) were around 40 ppm lower than after the MBE. The reasons for this difference remain unclear. A recent hypothesis proposed that changes in oceanic circulation, in response to different external forcings before and after the MBE, might have increased the ocean carbon storage in pre-MBE interglacials, thus lowering atmospheric CO 2 . Nevertheless, no quantitative estimate of this hypothesis has been produced up to now. Here we use an intermediate complexity model including the carbon cycle to evaluate the response of the carbon reservoirs in the atmosphere, ocean and land in response to the changes of orbital forcings, ice sheet configurations and atmospheric CO 2 concentrations over the last nine interglacials. We show that the ocean takes up more carbon during pre-MBE interglacials in agreement with data, but the impact on atmospheric CO 2 is limited to a few parts per million. Terrestrial biosphere is simulated to be less developed in pre-MBE interglacials, which reduces the storage of carbon on land and increases atmospheric CO 2 . Accounting for different simulated ice sheet extents modifies the vegetation cover and temperature, and thus the carbon reservoir distribution. Overall, atmospheric CO 2 levels are lower during these pre-MBE simulated interglacials including all these effects, but the magnitude is still far too small. These results suggest a possible misrepresentation of some key processes in the model, such as the magnitude of ocean circulation changes, or the lack of crucial mechanisms or internal feedbacks, such as those related to permafrost, to fully account for the lower atmospheric CO 2 concentrations during pre-MBE interglacials. Text Ice Ice Sheet permafrost Copernicus Publications: E-Journals Climate of the Past 14 2 239 253 |
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Copernicus Publications: E-Journals |
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English |
description |
Atmospheric CO 2 levels during interglacials prior to the Mid-Brunhes Event (MBE, ∼ 430 ka BP ) were around 40 ppm lower than after the MBE. The reasons for this difference remain unclear. A recent hypothesis proposed that changes in oceanic circulation, in response to different external forcings before and after the MBE, might have increased the ocean carbon storage in pre-MBE interglacials, thus lowering atmospheric CO 2 . Nevertheless, no quantitative estimate of this hypothesis has been produced up to now. Here we use an intermediate complexity model including the carbon cycle to evaluate the response of the carbon reservoirs in the atmosphere, ocean and land in response to the changes of orbital forcings, ice sheet configurations and atmospheric CO 2 concentrations over the last nine interglacials. We show that the ocean takes up more carbon during pre-MBE interglacials in agreement with data, but the impact on atmospheric CO 2 is limited to a few parts per million. Terrestrial biosphere is simulated to be less developed in pre-MBE interglacials, which reduces the storage of carbon on land and increases atmospheric CO 2 . Accounting for different simulated ice sheet extents modifies the vegetation cover and temperature, and thus the carbon reservoir distribution. Overall, atmospheric CO 2 levels are lower during these pre-MBE simulated interglacials including all these effects, but the magnitude is still far too small. These results suggest a possible misrepresentation of some key processes in the model, such as the magnitude of ocean circulation changes, or the lack of crucial mechanisms or internal feedbacks, such as those related to permafrost, to fully account for the lower atmospheric CO 2 concentrations during pre-MBE interglacials. |
format |
Text |
author |
Bouttes, Nathaelle Swingedouw, Didier Roche, Didier M. Sanchez-Goni, Maria F. Crosta, Xavier |
spellingShingle |
Bouttes, Nathaelle Swingedouw, Didier Roche, Didier M. Sanchez-Goni, Maria F. Crosta, Xavier Response of the carbon cycle in an intermediate complexity model to the different climate configurations of the last nine interglacials |
author_facet |
Bouttes, Nathaelle Swingedouw, Didier Roche, Didier M. Sanchez-Goni, Maria F. Crosta, Xavier |
author_sort |
Bouttes, Nathaelle |
title |
Response of the carbon cycle in an intermediate complexity model to the different climate configurations of the last nine interglacials |
title_short |
Response of the carbon cycle in an intermediate complexity model to the different climate configurations of the last nine interglacials |
title_full |
Response of the carbon cycle in an intermediate complexity model to the different climate configurations of the last nine interglacials |
title_fullStr |
Response of the carbon cycle in an intermediate complexity model to the different climate configurations of the last nine interglacials |
title_full_unstemmed |
Response of the carbon cycle in an intermediate complexity model to the different climate configurations of the last nine interglacials |
title_sort |
response of the carbon cycle in an intermediate complexity model to the different climate configurations of the last nine interglacials |
publishDate |
2019 |
url |
https://doi.org/10.5194/cp-14-239-2018 https://cp.copernicus.org/articles/14/239/2018/ |
genre |
Ice Ice Sheet permafrost |
genre_facet |
Ice Ice Sheet permafrost |
op_source |
eISSN: 1814-9332 |
op_relation |
doi:10.5194/cp-14-239-2018 https://cp.copernicus.org/articles/14/239/2018/ |
op_doi |
https://doi.org/10.5194/cp-14-239-2018 |
container_title |
Climate of the Past |
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14 |
container_issue |
2 |
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239 |
op_container_end_page |
253 |
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1766028078046248960 |