Articles | Volume 21, issue 1
https://doi.org/10.5194/bg-21-261-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/bg-21-261-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| Highlight paper
| 
16 Jan 2024
Research article | Highlight paper |
| 16 Jan 2024
| 16 Jan 2024
The additionality problem of ocean alkalinity enhancement
Lennart Thomas Bach
CORRESPONDING AUTHOR
Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, TAS, Australia
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Total article views: 6,286 (including HTML, PDF, and XML)
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Total article views: 4,587 (including HTML, PDF, and XML)
Thereof 4,301 with geography defined
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Total article views: 1,699 (including HTML, PDF, and XML)
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Cited
16 citations as recorded by crossref.
- A numerical assessment of ocean alkalinity enhancement efficiency on a river-dominated continental shelf—a case study in the northern Gulf of Mexico Y. Ou et al. 10.1088/1748-9326/adaa8b
- No compromise in efficiency from the co-application of a marine and a terrestrial CDR method Y. Moustakis et al. 10.1038/s41467-025-59982-x
- Global carbonate chemistry gradients reveal a negative feedback on ocean alkalinity enhancement N. Lehmann & L. Bach 10.1038/s41561-025-01644-0
- Review and syntheses: Ocean alkalinity enhancement and carbon dioxide removal through marine enhanced rock weathering using olivine L. Geerts et al. 10.5194/bg-22-355-2025
- Effects of ocean alkalinity enhancement on plankton in the Equatorial Pacific J. Guo et al. 10.1038/s43247-025-02248-7
- Direct effects of ocean alkalinity enhancement in the Baltic Sea–results from in-silico experiments A. Anschütz et al. 10.3389/fclim.2025.1450468
- Calcite is an efficient and low-cost material to enhance benthic weathering in shelf sediments of the Baltic Sea M. Fuhr et al. 10.1038/s43247-025-02079-6
- The CDR potential of olivine-based enhanced rock weathering in marine systems: a case study for the coastal zone of France L. Geerts et al. 10.1088/1748-9326/addf60
- Metrics for quantifying the efficiency of atmospheric CO2 reduction by marine carbon dioxide removal (mCDR) K. Yamamoto et al. 10.1088/1748-9326/ad7477
- Seawater carbonate chemistry based carbon dioxide removal: towards commonly agreed principles for carbon monitoring, reporting, and verification P. Halloran et al. 10.3389/fclim.2025.1487138
- Laying waste to the deep: parallel narratives of marine carbon dioxide removal and deep-seabed mining S. Lidström et al. 10.1038/s44183-024-00075-5
- Mapping the global variation in the efficiency of ocean alkalinity enhancement for carbon dioxide removal M. Zhou et al. 10.1038/s41558-024-02179-9
- Aotearoa New Zealand’s marine carbon cycle in a changing climate – Current understanding and future directions S. Nodder et al. 10.1080/00288330.2025.2461289
- An assessment of ocean alkalinity enhancement using aqueous hydroxides: kinetics, efficiency, and precipitation thresholds M. Ringham et al. 10.5194/bg-21-3551-2024
- Perspectives and challenges of marine carbon dioxide removal A. Oschlies et al. 10.3389/fclim.2024.1506181
- The additionality problem of ocean alkalinity enhancement L. Bach 10.5194/bg-21-261-2024
15 citations as recorded by crossref.
- A numerical assessment of ocean alkalinity enhancement efficiency on a river-dominated continental shelf—a case study in the northern Gulf of Mexico Y. Ou et al. 10.1088/1748-9326/adaa8b
- No compromise in efficiency from the co-application of a marine and a terrestrial CDR method Y. Moustakis et al. 10.1038/s41467-025-59982-x
- Global carbonate chemistry gradients reveal a negative feedback on ocean alkalinity enhancement N. Lehmann & L. Bach 10.1038/s41561-025-01644-0
- Review and syntheses: Ocean alkalinity enhancement and carbon dioxide removal through marine enhanced rock weathering using olivine L. Geerts et al. 10.5194/bg-22-355-2025
- Effects of ocean alkalinity enhancement on plankton in the Equatorial Pacific J. Guo et al. 10.1038/s43247-025-02248-7
- Direct effects of ocean alkalinity enhancement in the Baltic Sea–results from in-silico experiments A. Anschütz et al. 10.3389/fclim.2025.1450468
- Calcite is an efficient and low-cost material to enhance benthic weathering in shelf sediments of the Baltic Sea M. Fuhr et al. 10.1038/s43247-025-02079-6
- The CDR potential of olivine-based enhanced rock weathering in marine systems: a case study for the coastal zone of France L. Geerts et al. 10.1088/1748-9326/addf60
- Metrics for quantifying the efficiency of atmospheric CO2 reduction by marine carbon dioxide removal (mCDR) K. Yamamoto et al. 10.1088/1748-9326/ad7477
- Seawater carbonate chemistry based carbon dioxide removal: towards commonly agreed principles for carbon monitoring, reporting, and verification P. Halloran et al. 10.3389/fclim.2025.1487138
- Laying waste to the deep: parallel narratives of marine carbon dioxide removal and deep-seabed mining S. Lidström et al. 10.1038/s44183-024-00075-5
- Mapping the global variation in the efficiency of ocean alkalinity enhancement for carbon dioxide removal M. Zhou et al. 10.1038/s41558-024-02179-9
- Aotearoa New Zealand’s marine carbon cycle in a changing climate – Current understanding and future directions S. Nodder et al. 10.1080/00288330.2025.2461289
- An assessment of ocean alkalinity enhancement using aqueous hydroxides: kinetics, efficiency, and precipitation thresholds M. Ringham et al. 10.5194/bg-21-3551-2024
- Perspectives and challenges of marine carbon dioxide removal A. Oschlies et al. 10.3389/fclim.2024.1506181
1 citations as recorded by crossref.
Latest update: 22 Jun 2025
Co-editor-in-chief
Reaching the Paris Agreement targets to limit global warming to 1.5 or 2°C implies not only reducing emissions, but also active carbon dioxide removal from the atmosphere. While land-based carbon dioxide removal or negative emission technologies have received most attention, ocean solutions are increasingly being considered. Ocean alkalinity enhancement (OAE), or alkalinization, is one promising ocean-based carbon dioxide technology. However, any new carbon dioxide removal technique needs thorough investigations for its effectiveness, longevity, benefits and lack of disbenefits, financial viability, social acceptance and governability. The paper by Bach is a nice illustration of the type of research that must be done if we are to consider large scale application of OAE. It focuses on the additionality problem of ocean alkalinity enhancement, specifically it investigates how the addition of alkalinity modifies the natural alkalinity cycle and in that way the efficiency of carbon dioxide sequestration.
Reaching the Paris Agreement targets to limit global warming to 1.5 or 2°C implies not only...
Short summary
Ocean alkalinity enhancement (OAE) is a widely considered marine carbon dioxide removal method. OAE aims to accelerate chemical rock weathering, which is a natural process that slowly sequesters atmospheric carbon dioxide. This study shows that the addition of anthropogenic alkalinity via OAE can reduce the natural release of alkalinity and, therefore, reduce the efficiency of OAE for climate mitigation. However, the additionality problem could be mitigated via a variety of activities.
Ocean alkalinity enhancement (OAE) is a widely considered marine carbon dioxide removal method....
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