Marine CDR science meets social science – organizing the next generation of ocean iron fertilization field studies

Decarbonization of anthropogenic activities is progressing too slowly, creating an urgent need to actively remove carbon dioxide (CO₂) from our atmosphere if we are to prevent the most severe consequences of a disrupted climate system. The marine environment offers several potential approaches for sequestering carbon, with iron-enhanced biological productivity being the most extensively studied. However, past iron addition studies were not primarily aimed at quantifying the durability of carbon storage, nor did they evaluate how prudent this approach might be as a marine carbon dioxide removal (mCDR) approach. A new generation of field studies is needed to address knowledge gaps and uncertainties regarding the effectiveness, scalability, reproducibility, and cost of iron addition for mCDR. These future field experiments need to be conducted on significantly larger spatial scales (over ten times larger) and longer in duration (multi-seasonal rather than the typical one-month studies) compared to previous mesoscale iron addition studies. Core measurements are required to quantify key factors such as: CO₂ drawdown in the surface ocean, the re-equilibration timescales of atmospheric CO₂ with the surface ocean, the sinking transport of carbon to depth, and the portion of this flux that results in carbon sequestration for 100 years or more. Attention must also be given to the ecological and environmental consequences of iron addition, necessitating a combination of remote sensing, in-situ observations, and modeling. Initial field trials are proposed for the iron-limited high seas of the NE Pacific, chosen for specific reasons outlined in this presentation. These field trials must be developed and conducted in collaboration with social science and governance experts to ensure they are deployed with community engagement, and in an equitable, just, and ethical manner, with the appropriate social safeguards. This presentation reflects the contributions of a diverse group of international and multidisciplinary experts, all of whom are committed to a responsible code of conduct as part of the Exploring Ocean Iron Solutions (ExOIS) consortium. Now is the time for actionable studies to begin. https://oceaniron.org/