Articles | Volume 23, issue 10
https://doi.org/10.5194/bg-23-3299-2026
© Author(s) 2026. 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-23-3299-2026
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
18 May 2026
Research article |
| 18 May 2026
| 18 May 2026
The efficiency and ocean acidification mitigation potential of ocean alkalinity enhancement on multi-centennial timescales
Hendrik Grosselindemann
CORRESPONDING AUTHOR
University of Bern, Climate and Environmental Physics, Bern, Switzerland
University of Bern, Oeschger Centre for Climate Change Research, Bern, Switzerland
Friedrich A. Burger
University of Bern, Climate and Environmental Physics, Bern, Switzerland
University of Bern, Oeschger Centre for Climate Change Research, Bern, Switzerland
Thomas L. Frölicher
University of Bern, Climate and Environmental Physics, Bern, Switzerland
University of Bern, Oeschger Centre for Climate Change Research, Bern, Switzerland
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Ocean alkalinity enhancement is viewed as a promising option for carbon dioxide removal. When alkalinity is added in the open ocean through mineral powders, carbon uptake from the atmosphere is decreased when mineral particles sink before fully dissolving. Here we prescribe vertical alkalinity release profiles to an Earth system model. We show that carbon uptake may initially decrease by more than 75% when grain size doubles and that full uptake is delayed by centuries and spatially dispersed.
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Biogeosciences Discuss., https://doi.org/10.5194/bg-2023-182, https://doi.org/10.5194/bg-2023-182, 2023
Revised manuscript not accepted
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For assessing the consequences of human-induced climate change for the marine realm, it is necessary to not only look at gradual changes but also at abrupt changes of environmental conditions. We summarise abrupt changes in ocean warming, acidification, and oxygen concentration as the key environmental factors for ecosystems. Taking these abrupt changes into account requires greenhouse gas emissions to be reduced to a larger extent than previously thought to limit respective damage.
Anne L. Morée, Tayler M. Clarke, William W. L. Cheung, and Thomas L. Frölicher
Biogeosciences, 20, 2425–2454, https://doi.org/10.5194/bg-20-2425-2023, https://doi.org/10.5194/bg-20-2425-2023, 2023
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Ocean temperature and oxygen shape marine habitats together with species’ characteristics. We calculated the impacts of projected 21st-century warming and oxygen loss on the contemporary habitat volume of 47 marine species and described the drivers of these impacts. Most species lose less than 5 % of their habitat at 2 °C of global warming, but some species incur losses 2–3 times greater than that. We also calculate which species may be most vulnerable to climate change and why this is the case.
Natacha Le Grix, Jakob Zscheischler, Keith B. Rodgers, Ryohei Yamaguchi, and Thomas L. Frölicher
Biogeosciences, 19, 5807–5835, https://doi.org/10.5194/bg-19-5807-2022, https://doi.org/10.5194/bg-19-5807-2022, 2022
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Compound events threaten marine ecosystems. Here, we investigate the potentially harmful combination of marine heatwaves with low phytoplankton productivity. Using satellite-based observations, we show that these compound events are frequent in the low latitudes. We then investigate the drivers of these compound events using Earth system models. The models share similar drivers in the low latitudes but disagree in the high latitudes due to divergent factors limiting phytoplankton production.
Jens Terhaar, Thomas L. Frölicher, and Fortunat Joos
Biogeosciences, 19, 4431–4457, https://doi.org/10.5194/bg-19-4431-2022, https://doi.org/10.5194/bg-19-4431-2022, 2022
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Estimates of the ocean sink of anthropogenic carbon vary across various approaches. We show that the global ocean carbon sink can be estimated by three parameters, two of which approximate the ocean ventilation in the Southern Ocean and the North Atlantic, and one of which approximates the chemical capacity of the ocean to take up carbon. With observations of these parameters, we estimate that the global ocean carbon sink is 10 % larger than previously assumed, and we cut uncertainties in half.
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Short summary
We assess the long-term carbon cycle, climate and ocean acidification response of ocean alkalinity enhancement (OAE) using an emission-driven Earth system model across warming stabilization scenarios. OAE lowers atmospheric CO2 and produces a scenario-independent linear cooling. Gross carbon capture efficiency remains high, while net efficiencies decline over time due to carbon-cycle feedbacks. Ocean acidification mitigation by OAE is dominated by CO2 drawdown on long timescales.
We assess the long-term carbon cycle, climate and ocean acidification response of ocean...
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