The carbonate pump feedback on alkalinity and the carbon cycle in the 21st century and beyond
International audience Abstract. Ocean acidification is likely to impact all stages of the ocean carbonate pump, i.e. the production, export, dissolution and burial of biogenic CaCO3. However, the associated feedback on anthropogenic carbon uptake and ocean acidification has received little attentio...
Published in: | Earth System Dynamics |
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ftepunivpsaclay:oai:HAL:hal-04573499v1 2024-06-09T07:48:44+00:00 The carbonate pump feedback on alkalinity and the carbon cycle in the 21st century and beyond Planchat, Alban Bopp, Laurent Kwiatkowski, Lester Torres, Olivier Laboratoire de Météorologie Dynamique (UMR 8539) (LMD) Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris École normale supérieure - Paris (ENS-PSL) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-École normale supérieure - Paris (ENS-PSL) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL) 2024-05-03 https://hal.sorbonne-universite.fr/hal-04573499 https://hal.sorbonne-universite.fr/hal-04573499/document https://hal.sorbonne-universite.fr/hal-04573499/file/esd-15-565-2024.pdf https://doi.org/10.5194/esd-15-565-2024 en eng HAL CCSD European Geosciences Union info:eu-repo/semantics/altIdentifier/doi/10.5194/esd-15-565-2024 hal-04573499 https://hal.sorbonne-universite.fr/hal-04573499 https://hal.sorbonne-universite.fr/hal-04573499/document https://hal.sorbonne-universite.fr/hal-04573499/file/esd-15-565-2024.pdf doi:10.5194/esd-15-565-2024 http://creativecommons.org/licenses/by/ info:eu-repo/semantics/OpenAccess ISSN: 2190-4979 EISSN: 2190-4987 Earth System Dynamics https://hal.sorbonne-universite.fr/hal-04573499 Earth System Dynamics, 2024, 15 (3), pp.565 - 588. ⟨10.5194/esd-15-565-2024⟩ [SDE]Environmental Sciences info:eu-repo/semantics/article Journal articles 2024 ftepunivpsaclay https://doi.org/10.5194/esd-15-565-2024 2024-05-16T11:37:12Z International audience Abstract. Ocean acidification is likely to impact all stages of the ocean carbonate pump, i.e. the production, export, dissolution and burial of biogenic CaCO3. However, the associated feedback on anthropogenic carbon uptake and ocean acidification has received little attention. It has previously been shown that Earth system model (ESM) carbonate pump parameterizations can affect and drive biases in the representation of ocean alkalinity, which is critical to the uptake of atmospheric carbon and provides buffering capacity towards associated acidification. In the sixth phase of the Coupled Model Intercomparison Project (CMIP6), we show divergent responses of CaCO3 export at 100 m this century, with anomalies by 2100 ranging from −74 % to +23 % under a high-emission scenario. The greatest export declines are projected by ESMs that consider pelagic CaCO3 production to depend on the local calcite/aragonite saturation state. Despite the potential effects of other processes on alkalinity, there is a robust negative correlation between anomalies in CaCO3 export and salinity-normalized surface alkalinity across the CMIP6 ensemble. Motivated by this relationship and the uncertainty in CaCO3 export projections across ESMs, we perform idealized simulations with an ocean biogeochemical model and confirm a limited impact of carbonate pump anomalies on 21st century ocean carbon uptake and acidification. However, we highlight a potentially abrupt shift, between 2100 and 2300, in the dissolution of CaCO3 from deep to subsurface waters when the global-scale mean calcite saturation state reaches about 1.23 at 500 m (likely when atmospheric CO2 reaches 900–1100 ppm). During this shift, upper ocean acidification due to anthropogenic carbon uptake induces deep ocean acidification driven by a substantial reduction in CaCO3 deep dissolution following its decreased export at depth. Although the effect of a diminished carbonate pump on global ocean carbon uptake and surface ocean acidification remains limited ... Article in Journal/Newspaper Ocean acidification École Polytechnique, Université Paris-Saclay: HAL Earth System Dynamics 15 3 565 588 |
institution |
Open Polar |
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École Polytechnique, Université Paris-Saclay: HAL |
op_collection_id |
ftepunivpsaclay |
language |
English |
topic |
[SDE]Environmental Sciences |
spellingShingle |
[SDE]Environmental Sciences Planchat, Alban Bopp, Laurent Kwiatkowski, Lester Torres, Olivier The carbonate pump feedback on alkalinity and the carbon cycle in the 21st century and beyond |
topic_facet |
[SDE]Environmental Sciences |
description |
International audience Abstract. Ocean acidification is likely to impact all stages of the ocean carbonate pump, i.e. the production, export, dissolution and burial of biogenic CaCO3. However, the associated feedback on anthropogenic carbon uptake and ocean acidification has received little attention. It has previously been shown that Earth system model (ESM) carbonate pump parameterizations can affect and drive biases in the representation of ocean alkalinity, which is critical to the uptake of atmospheric carbon and provides buffering capacity towards associated acidification. In the sixth phase of the Coupled Model Intercomparison Project (CMIP6), we show divergent responses of CaCO3 export at 100 m this century, with anomalies by 2100 ranging from −74 % to +23 % under a high-emission scenario. The greatest export declines are projected by ESMs that consider pelagic CaCO3 production to depend on the local calcite/aragonite saturation state. Despite the potential effects of other processes on alkalinity, there is a robust negative correlation between anomalies in CaCO3 export and salinity-normalized surface alkalinity across the CMIP6 ensemble. Motivated by this relationship and the uncertainty in CaCO3 export projections across ESMs, we perform idealized simulations with an ocean biogeochemical model and confirm a limited impact of carbonate pump anomalies on 21st century ocean carbon uptake and acidification. However, we highlight a potentially abrupt shift, between 2100 and 2300, in the dissolution of CaCO3 from deep to subsurface waters when the global-scale mean calcite saturation state reaches about 1.23 at 500 m (likely when atmospheric CO2 reaches 900–1100 ppm). During this shift, upper ocean acidification due to anthropogenic carbon uptake induces deep ocean acidification driven by a substantial reduction in CaCO3 deep dissolution following its decreased export at depth. Although the effect of a diminished carbonate pump on global ocean carbon uptake and surface ocean acidification remains limited ... |
author2 |
Laboratoire de Météorologie Dynamique (UMR 8539) (LMD) Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris École normale supérieure - Paris (ENS-PSL) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-École normale supérieure - Paris (ENS-PSL) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL) |
format |
Article in Journal/Newspaper |
author |
Planchat, Alban Bopp, Laurent Kwiatkowski, Lester Torres, Olivier |
author_facet |
Planchat, Alban Bopp, Laurent Kwiatkowski, Lester Torres, Olivier |
author_sort |
Planchat, Alban |
title |
The carbonate pump feedback on alkalinity and the carbon cycle in the 21st century and beyond |
title_short |
The carbonate pump feedback on alkalinity and the carbon cycle in the 21st century and beyond |
title_full |
The carbonate pump feedback on alkalinity and the carbon cycle in the 21st century and beyond |
title_fullStr |
The carbonate pump feedback on alkalinity and the carbon cycle in the 21st century and beyond |
title_full_unstemmed |
The carbonate pump feedback on alkalinity and the carbon cycle in the 21st century and beyond |
title_sort |
carbonate pump feedback on alkalinity and the carbon cycle in the 21st century and beyond |
publisher |
HAL CCSD |
publishDate |
2024 |
url |
https://hal.sorbonne-universite.fr/hal-04573499 https://hal.sorbonne-universite.fr/hal-04573499/document https://hal.sorbonne-universite.fr/hal-04573499/file/esd-15-565-2024.pdf https://doi.org/10.5194/esd-15-565-2024 |
genre |
Ocean acidification |
genre_facet |
Ocean acidification |
op_source |
ISSN: 2190-4979 EISSN: 2190-4987 Earth System Dynamics https://hal.sorbonne-universite.fr/hal-04573499 Earth System Dynamics, 2024, 15 (3), pp.565 - 588. ⟨10.5194/esd-15-565-2024⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.5194/esd-15-565-2024 hal-04573499 https://hal.sorbonne-universite.fr/hal-04573499 https://hal.sorbonne-universite.fr/hal-04573499/document https://hal.sorbonne-universite.fr/hal-04573499/file/esd-15-565-2024.pdf doi:10.5194/esd-15-565-2024 |
op_rights |
http://creativecommons.org/licenses/by/ info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.5194/esd-15-565-2024 |
container_title |
Earth System Dynamics |
container_volume |
15 |
container_issue |
3 |
container_start_page |
565 |
op_container_end_page |
588 |
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1801380614180438016 |