Establishing guidelines to support ocean sustainability

Urgent, evidence-based policies are needed to promote ocean sustainability. While global environmental assessments (GEAs) synthesizing ocean knowledge are growing, their processes must ensure social legitimacy, scientific credibility, and relevance to decision-makers. We conducted a review to consolidate best practices for GEAs to achieve legitimacy, credibility, and salience, and developed a standardized framework to assess their implementation and the coverage of ocean knowledge. The application of this framework to 12 influential reports shows that credibility practices are well implemented but that opportunities remain to enhance legitimacy and salience, particularly by increasing stakeholder engagement and diversifying knowledge representation. Key pathways to strengthen GEAs include developing knowledge-weaving practices, capturing regional diversity, multi-level approaches, greater transparency, and inter-assessment coordination to address ocean sustainability challenges. Such efforts should also yield guidelines for examining emerging technological approaches and associated research activities that address feasibility, effectiveness and trade-offs, such as between climate mitigation technologies and measures to strengthen biodiversity and its climate resilience.