How does the BBNJ Agreement on marine biodiversity work alongside other global frameworks?

The Agreement on the Conservation and Sustainable Use of Marine Biological Diversity of Areas Beyond National Jurisdiction, commonly known as the BBNJ [Biodiversity Beyond National Jurisdiction] Agreement or High Seas Treaty, is a key instrument for global ocean conservation. The Agreement sits within a complex landscape of overlapping international frameworks covering biodiversity, wildlife, ocean, climate and seabed mining – all of which need to be holistically implemented for conserving our interconnected ecological systems. Understanding how the BBNJ Agreement interacts with these other regimes is essential to assessing whether it can deliver its objectives, and where regulatory overlaps and gaps exist.

BBNJ and international biodiversity frameworks

Global Biodiversity Framework and Convention on Biological Diversity

The BBNJ Agreement is closely connected to the Global Biodiversity Framework (‘GBF’) under the Convention on Biological Diversity (‘CBD’), particularly its 30×30 area-based target: the commitment to protect at least 30% of the world’s land and sea area by 2030. By enabling the creation of marine protected areas in the high seas, the BBNJ is the main mechanism for reaching the 30×30 target for the oceans at the global scale.

Although the BBNJ Agreement does not explicitly refer to the 30×30 target, the Agreement will need to work with the GBF to ensure that marine protected areas are “ecologically representative, well-connected and equitably governed”, as outlined in the GBF. Parties can submit proposals for establishing marine protected areas and other area-based management tools.

The BBNJ Agreement provides the framework for fair and equitable sharing of benefits from the utilisation of marine genetic resources and digital sequence information that are found in the high seas. This can be a complex issue due to challenges in attributing benefits to specific states. Here, the experience of the Nagoya Protocol on Access to Genetic Resources and the Fair and Equitable Sharing of Benefits Arising from their Utilization, which is a supplementary agreement to the CBD, can offer critical insights. To address the challenges, the BBNJ Agreement requires state parties to deposit resources and information in publicly accessible repositories and databases. But detailed enforcement guidelines still need to be fleshed out.

Conventions on migratory species and trade in endangered species

There are two more international agreements that would stand to gain from the implementation of the BBNJ Agreement. First, the Convention on the Conservation of Migratory Species of Wild Animals (CMS) aims to conserve migratory species that cross national borders, and their habitats along migration routes. The CMS provides a legal foundation for internationally coordinated conservation measures throughout covered species’ migratory range. Many migratory marine species use the high seas and face multiple threats including pollution, by-catch, overfishing and habitat destruction. Multiple policies and Memoranda of Understanding agreed under the CMS, including those focused on protection of marine species like whales, sharks, rays, turtles and cetaceans, are directly relevant for effective implementation of the BBNJ’s objectives of conservation and sustainable use of biodiversity in the high seas.

Second, the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) aims to ensure that the international wildlife trade is sustainable, legal and traceable. CITES currently offers different levels of protection to around 2,400 marine species. Many threatened species in the high seas, currently outside CITES’ remit, lack the same level of protection from illegal trade. The BBNJ Agreement would complement CITES were it to establish a framework for habitat protection in the high seas.

BBNJ and the international climate framework

Both the UN Framework Convention on Climate Change and its Paris Agreement recognise the ocean as part of the climate system, but binding ocean-specific implementation has long lagged behind land-based action. However, that is beginning to change. The Ocean and Climate Change Dialogue was established at the COP25 summit in 2019 as a dedicated annual space to advance ocean-based climate action. The 2025 NDC [Nationally Determined Contribution] Synthesis Report found that 78% of countries now include at least one reference to the ocean in their national climate plans. The BBNJ Agreement strengthens this ocean–climate nexus by enabling synergy between measures within and beyond national jurisdictions. There is also willingness to coordinate action across NDCs, National Adaptation Plans (NAPs) and National Biodiversity Strategies and Action Plans (NBSAPs).

BBNJ and existing global ocean frameworks

International Seabed Authority Mining Code

The operation of the BBNJ Agreement intersects with the mandate of the International Seabed Authority (ISA). The ISA is an intergovernmental body established under the UN Convention on the Law of the Sea (UNCLOS) to regulate mineral extraction from the international seabed. As the BBNJ Agreement and the ISA deal with marine biodiversity and mineral extraction respectively in the same maritime zone – areas beyond national jurisdiction – their activities are deeply interconnected. For instance, extraction activities such as deep-sea mining can affect marine biodiversity. However, the BBNJ Agreement does not at present clarify these connections or potential regulatory overlaps.

The ISA oversees exploration activities by contractors in areas such as the Clarion-Clipperton Zone in the Pacific, though no commercial exploitation has yet begun. A ‘Mining Code’ is set to be finalised by the end of 2026, after significant delay. Forty-three ISA member states have called for a moratorium or precautionary pause on deep sea mining, pending clearer environmental standards, while others are pressing to proceed. The BBNJ Agreement has introduced environmental impact assessment (EIA) requirements in this contested space, the standards and guidelines for which are to be developed by the Agreement’s Scientific and Technical Body. How these two regimes align in practice will determine whether the BBNJ Agreement raises the bar for deep-sea environmental governance or whether extraction activities advance under parallel rules or overlapping governance.

Regional programmes

The Regional Seas Programme (RSP) is the UN Environment Programme’s flagship programme for regional management of shared coastal and marine ecosystems. Currently working on 18 regional seas, it could serve as a critical platform for ensuring cooperation between institutions governing areas within and beyond national jurisdictions and translating global commitments in the BBNJ Agreement into regional action. Positive signs have started to emerge: the parties of many multilateral agreements under the RSP, including the Nairobi Convention covering states in the Western Indian Ocean, have adopted decisions and ministerial declarations relating to BBNJ and established working group for developing regional BBNJ implementation frameworks.

Regional Fisheries Management Organisations (RFMOs) are international organisations for conservation and sustainable management of specific fish species, especially those migrating across jurisdictions. The BBNJ is deeply interlinked with the RFMOs: its implementation could improve fishing stocks globally and the RFMOs’ fishing activities will impact the Agreement’s marine conservation and sustainable use objectives in the high seas.

Institutions formed under the BBNJ Agreement can also utilise the knowledge and expertise of both the RSP and the RFMOs in decision-making.

What is the likely future?

The BBNJ Agreement has entered a densely populated institutional landscape. The varying mandates and authorities of different institutions raise questions of regulatory overlaps among existing institutions, and which institution will get precedence in case of inconsistencies. The BBNJ Agreement’s aim of conservation and sustainable use of marine biodiversity without ‘undermining’ other relevant legal instruments, frameworks and bodies indicates its focus on enhanced international cooperation and coordination. It also encourages alignment of existing frameworks and institutions with its objectives, by urging parties to promote the Agreement’s objectives when taking decisions under other relevant instruments and frameworks. It will be critical to examine how these aspects evolve in practice.

This Explainer was written by Franka Huhn, Himanshu Pabreja and Carol Yuen. Georgina Kyriacou edited the Explainer.