Novel climate interventions are proliferating and upscaling in marine systems. However, how social impacts are managed remains unclear. We combine a global survey of intervention actors, interviews with best-practice leaders, and policy analysis to assess whether and how social responsibility is considered when proposing, testing, and/or implementing 76 marine climate interventions worldwide. We find that technical feasibility trumps social considerations. Feasibility assessments predominantly rely on biophysical data (63%), with 54% either not using social data or relying on spatial marine use data as the only social data source. Where public deliberation opportunities are available (61%), most are via formal regulatory channels (54%), with only 15% offering more inclusive engagement. Best-practice leaders confirm low organizational competency around social impact. Social responsibility is rarely mandated by governments and instead relies on voluntary initiation by emerging best-practice leaders. Extension and codification of best practices are urgently required for socially responsible governance of new marine climate interventions.