Ocean Alkalinity Enhancement (OAE) is proposed as one approach to carbon dioxide removal (CDR) to mitigate the effects of anthropogenic CO₂ on Earth’s climate after substantial emissions reductions. Successful deployment of such technology at scale hinges in part on demonstrating safety, durability, and a precise methodology for quantifying and verifying CDR resulting from alkalinity enhancement.

Collaborative OAE field research between Dalhousie University and Planetary Technologies has been ongoing in Halifax Harbour, Canada, since 2023, providing a learning ground for developing fit-for-purpose monitoring, response and verification (MRV) strategies for quantifying and verifying mCDR under realistic deployment conditions.

This talk will focus on the measurement and observational aspects of MRV and their interaction with biogeochemical modelling. First, the quantitative assessment of baseline variability will be shown, and drivers of this variability will be explained. The presentation will then focus on strategies for detecting and attributing OAE signals and CDR in the field, and the vital role of high-resolution autonomous observing in it. More nuanced and detailed studies of the near-field processes affecting the carbonate system will showcase the spatio-temporal evolution of the alkaline plume and the in situ dissolution kinetics of the feedstock. Finally, the collected empirical data will be discussed in the context of its use in reducing uncertainty in CDR estimates by informing model development and validating model estimates against field data.