Regime Interaction in CBD and BBNJ Environmental Impact Assessments: Normative Framework and Challenges

The entry into force of the Agreement on the Conservation and Sustainable Use of Marine Biological Diversity of Areas Beyond National Jurisdiction (BBNJ Agreement) on 17 January 2026 marks a transformative moment in ocean governance. Historically, biodiversity beyond national jurisdiction has been governed through a fragmented patchwork of legal instruments, frameworks and bodies, resulting in regulatory and institutional gaps and challenges for coherent conservation. This article examines regime interaction between the BBNJ Agreement and the Convention on Biological Diversity (CBD) in the context of environmental impact assessments (EIAs). It addresses three questions: how regime interaction should be governed, what implementation challenges are likely to arise, and how those challenges can be addressed. The analysis argues that although the BBNJ Agreement establishes a comprehensive normative framework for regime interaction, its effectiveness is hindered by ambiguities surrounding key terms such as “undermine”, “relevant”, “equivalent”, “mechanism”, and “collaborate”. Rather than relying on gradual evolutionary interpretation, this article advocates a proactive approach grounded in the quasi-legislative function vested in the Conference of the Parties (COP) under Articles 47(3) and 48 of the BBNJ Agreement and Article 23(4) of the CBD. It concludes that the strategic exercise of the rule and norm-making functions of the COP offers the most effective pathway to operationalizing coherent regime interaction.