Myridinas et al. (2026): Prospective site-specific life cycle assessment of ocean alkalinity enhancement

Maria Myridinas, Katja Fennel, Arnaud Laurent, Romain Sacchi, Andrea Stöckli, Karin Treyer, Christian Bauer and Stephan Pfister, IN: Environmental Research Letters, https://doi.org/10.1088/1748-9326/ae5a4e

Ocean alkalinity enhancement (OAE) is a promising marine carbon dioxide removal (CDR) option, but its net climate benefit and wider environmental implications depend strongly on where, and how it is implemented and on decarbonized energy and material supply chains. The authors develop a prospective, site-specific, life cycle assessment (pLCA) that couples a field trials’ validated high-resolution ocean biogeochemical model with LCA for five OAE pathways deployed via wastewater outfalls in Halifax Harbor, Canada: three on magnesium hydroxide (two from serpentinite, via ammonium sulfate (AS) and HCl leaching (HCl), one from bischofite brine (BIS)) and two on sodium hydroxide (from industrial-grade sodium chloride (NaOHs) and seawater desalination brine hydroxide (NaOHb)). Using the functional unit of removing and permanently storing 1 t of atmospheric CO₂, the authors compare present-day conditions with a 2050 scenario and quantify eighteen ReCiPe 2016 midpoint impacts.

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