Interdisciplinary collaboration to develop a robust and implementable monitoring, reporting, and verification (MRV) protocol for Ocean Alkalinity Enhancement (OAE)

The marine carbon dioxide removal (mCDR) industry is undergoing rapid growth, with many stakeholders deploying mCDR pilot projects. In order to establish a scientific basis for environmental safety and carbon accounting in mCDR, there is a need for rigorous, transparent and scientifically robust monitoring, reporting, and verification (MRV) protocols. These protocols seek to ensure responsible scaling of mCDR projects that have demonstrable net-negative atmospheric impacts. One of the main MRV challenges facing the mCDR pathway of Ocean Alkalinity Enhancement (OAE) is that direct measurements in the marine environment can be difficult to obtain. Here, we present the highlights of the first version of the Isometric OAE MRV protocol and focus on the process for interdisciplinary collaboration that informed decision-making and iteration towards the current version. We focus specifically on the development of guidelines for quantifying additionality, durability and uncertainty in the open system OAE pathway, and elaborate on our modeling requirements and benchmarks, as well as guidance on how models should be validated with environmental data. Ultimately, we aim to receive feedback on the protocol and our approach in order to apply this method to new versions and additional protocols and modules across mCDR and other CDR pathways.