Even where the scientific case for a particular mCDR approach is strong, moving from promising research to meaningful deployment means overcoming obstacles that extend well beyond the chemistry. This post sets out the main barriers identified by SEAO2-CDR, offering a working map of the areas that require attention.
1. The measurement problem
Perhaps the most fundamental challenge is proving that carbon has been removed: how much, and for how long?
For most mCDR approaches, reliable and cost-effective systems for measurement, reporting, and verification (MRV) do not yet exist. Without them, removal credits cannot be trusted, regulations cannot be properly enforced, and public confidence will be difficult to build. Developing MRV frameworks suited to different mCDR approaches is therefore one of SEAO2-CDR’s central tasks.
2. Ecological uncertainty
Adding minerals, stimulating algal blooms, or restructuring coastal ecosystems may produce effects that cascade unpredictably through food webs, nutrient cycles, and local marine environments. This does not mean that mCDR is inherently dangerous. It does mean that responsible deployment must include ecological monitoring alongside carbon measurement. The two cannot be separated.
3. The governance gap
Who decides whether mCDR should be deployed, where it can take place, and under what conditions? International waters do not belong to any single state, while many mCDR techniques operate across multiple jurisdictions. Existing frameworks, including UNCLOS, the London Protocol, and the CBD, offer only partial and sometimes conflicting guidance.
The EU Carbon Removal Certification Framework (CRCF) is an important step, but it was designed primarily with terrestrial CDR in mind. How it will apply to marine approaches remains unresolved.
4. Economics and scale
Most mCDR approaches remain expensive relative to the amount of carbon removal they deliver. Costs are likely to fall as the techniques mature, but reaching a meaningful scale will require both further technological development and reliable market signals, neither of which currently exists to the necessary degree.
5. Social licence
Public and community attitudes towards ocean-based interventions vary considerably. Some approaches, particularly those perceived as large-scale manipulation of marine environments, face significant opposition. Building genuine social licence requires transparency, inclusive governance, and a demonstrated willingness to respond to local concerns.
The case for optimism
None of these barriers is permanent. They are challenges that rigorous research, thoughtful governance design, and sustained engagement can address. That is precisely what projects such as SEAO2-CDR are designed to do.