Public evaluations of four approaches to ocean-based carbon dioxide removal

In the face of mounting global climatic pressures, negative emission technologies (NETs) for carbon dioxide removal (CDR) are increasingly proposed as necessary for meeting climate targets. While initial work has identified the potential of terrestrial NETs, a diverse set of marine/ocean-based NETs are gaining new and particular attention. Emerging studies on the feasibility of marine NETs are urgently needed, especially to explore the logics that public groups use to judge different approaches, and to ensure that design and governance of these technologies align with public values and priorities. This study explores factors of interest in understanding public views on four marine NETs, both perceptions of climate severity and urgency, and beliefs about marine environments. It uses a quantitative survey to explore how a representative sample of people in British Columbia, Canada and Washington state, United States evaluate four marine NETs: coastal restoration; ocean alkalinity enhancement; ocean fertilization; and offshore direct air carbon capture and storage. We find that perceived severity and urgency of climate change predicts greater comfort with all NETs studied, and views of marine environments as adaptable, fragile and manageable vary in predicting both greater and lesser comfort. Drawing upon these insights, the paper offers reflections on the conditional thinking linked with emerging views of marine NETs, concluding with methodological suggestions for future research on public perceptions as concerns the deployment of ocean-based CDR near and long term. Incorporating these insights into policy for ocean-based CDR will be important to ensuring responsible governance of these technologies.Key policy insights Incorporating research on public perceptions will be important to the design of marine NETs and accompanying policies.Public groups in both British Columbia and Washington expressed high levels of comfort with coastal restoration, some comfort with offshore direct air carbon capture and storage, and some discomfort with ocean alkalinity enhancement and ocean fertilization.Perceived severity and urgency of climate change predicted greater comfort with all approaches; this evidence aligns with a small but growing body of scholarship indicating openness to environmental intervention amongst public groups concerned with climate impacts.Beliefs about marine environments, namely whether they are ‘adaptable’, ‘manageable’ or ‘fragile’, also predicted comfort, suggesting that CDR in ocean contexts requires further examination regarding public perceptions.