Grappling with a sea change: Tensions in expert imaginaries of marine carbon dioxide removal

While research on marine carbon dioxide removal (mCDR) expands apace, significant unknowns persist regarding the risks and benefits of individual mCDR options. This paper analyses the assumptions and expectations that animate expert understandings of mCDR, with a focus on issues that are central to the responsible governance of this emerging field of climate action. Drawing upon interviews with experts involved in mCDR research projects both academic and entrepreneurial, we highlight four thematic tensions that orient their thinking but are often unstated or left implicit in scientific and technical assessments: (1) the relevance of ‘naturalness’ as a criterion of evaluation for mCDR approaches; (2) the perceived need to accelerate research and development activities via alternative paradigms of evidence-building; (3) a framing of mCDR as a form of waste management that will, in turn, generate new (and currently poorly understood) forms of environmental pollutants; and (4) a commitment to inclusive governance mixed with difficulty in identifying specific stakeholders or constituencies in mCDR interventions. Although expert consensus on these four issues is unlikely, we suggest ways of ensuring that consideration of these themes enriches debate on the responsible development of novel mCDR capabilities.