Ocean iron fertilization may amplify climate change pressures on marine animal biomass for limited climate benefit

Tagliabue, Alessandro ORCID: 0000-0002-3572-3634, Twining, Benjamin S, Barrier, Nicolas, Maury, Olivier, Berger, Manon and Bopp, Laurent (2023) Ocean iron fertilization may amplify climate change pressures on marine animal biomass for limited climate benefit. GLOBAL CHANGE BIOLOGY, 29 (18). pp. 5250-5260.

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Official URL: http://dx.doi.org/10.1111/gcb.16854

Abstract

Climate change scenarios suggest that large-scale carbon dioxide removal (CDR) will be required to maintain global warming below 2°C, leading to renewed attention on ocean iron fertilization (OIF). Previous OIF modelling has found that while carbon export increases, nutrient transport to lower latitude ecosystems declines, resulting in a modest impact on atmospheric CO<sub>2</sub> . However, the interaction of these CDR responses with ongoing climate change is unknown. Here, we combine global ocean biogeochemistry and ecosystem models to show that, while stimulating carbon sequestration, OIF may amplify climate-induced declines in tropical ocean productivity and ecosystem biomass under a high-emission scenario, with very limited potential atmospheric CO<sub>2</sub> drawdown. The 'biogeochemical fingerprint' of climate change, that leads to depletion of upper ocean major nutrients due to upper ocean stratification, is reinforced by OIF due to greater major nutrient consumption. Our simulations show that reductions in upper trophic level animal biomass in tropical regions due to climate change would be exacerbated by OIF within ~20 years, especially in coastal exclusive economic zones (EEZs), with potential implications for fisheries that underpin the livelihoods and economies of coastal communities. Any fertilization-based CDR should therefore consider its interaction with ongoing climate-driven changes and the ensuing ecosystem impacts in national EEZs.

Item Type:	Article
Uncontrolled Keywords:	biogeochemical cycles, climate change, marine carbon dioxide removal, marine ecosystems, ocean iron fertilization, ocean net primary production
Divisions:	Faculty of Science and Engineering > School of Environmental Sciences
Depositing User:	Symplectic Admin
Date Deposited:	27 Jul 2023 15:24
Last Modified:	18 Aug 2023 08:33
DOI:	10.1111/gcb.16854
Open Access URL:	https://doi.org/10.1111/gcb.16854
Related URLs:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3171960