The Agreement on the Conservation and Sustainable Use of Marine Biological Diversity of Areas Beyond National Jurisdiction (BBNJ, hereinafter the Agreement), aimed at protecting biodiversity in the high seas that cover two-thirds of the world's oceans, entered into force on January 17. Attention is turning to how the Agreement may affect the South China Sea, long heated by sovereignty disputes and resource development.

The Agreement embodies a resolve to designate more than 30 percent of the high seas as marine protected areas by 2030 and to ensure fair use of biological resources from the high seas. It was adopted at the United Nations General Assembly in March 2023. As of last September, 60 of the 112 signatories, including South Korea, had completed ratification, bringing the Agreement into force worldwide in January. It is cited as a case in which international cooperation functioned to address a planetary problem despite geopolitical tensions.

With the Agreement now in effect, the South China Sea is drawing particular attention. In Association of Southeast Asian Nations (ASEAN) members that are engaged in sovereignty disputes with China, there is hope it can serve as a tool to check China. By declaring the high seas the common heritage of humankind, it provides a normative basis to criticize Chinese unilateralism. Viet Hoang, a professor at Ho Chi Minh City University of Law, told the South China Morning Post (SCMP) that, in the long term, the Agreement could shift the game in the South China Sea from competition based on power to competition based on rules.

Singaporean broadcaster CNA reported that, under the Agreement, negotiations will follow on marine protected areas, environmental impact assessment, and scientific cooperation; it assessed that the pact may not fully resolve disputes surrounding the South China Sea but could indirectly affect claimant states, including China and several ASEAN members. Nguyen Minh Vu, standing vice minister at the Ministry of Foreign Affairs of Vietnam, said in a recent interview with the state-run VNA that Vietnam has gained unprecedented opportunities and space for cooperation through the Agreement.

China, a party to the South China Sea conflict, played an active role in ushering in the Agreement. The 15th meeting of the Conference of the Parties to the UN Convention on Biological Diversity (COP15), which paved the way for consensus on the Agreement, was split between Kunming, China, in 2021 and Montreal, Canada, in 2022 due to the COVID-19 pandemic. Hence the Agreement is also referred to as the Kunming-Montreal Biodiversity Agreement.

China recently announced, together with Belgium and Chile, a bid to host the Agreement's secretariat. Observers say it seeks to highlight a responsible posture in contrast to the United States, which is withdrawing from various UN bodies. It also signals that putting the Agreement on track is important to China in terms of national strategy.

Concerns also exist that the Agreement could be used amid geopolitical tensions. It remains uncertain whether areas that countries including China, Vietnam, and the Philippines claim as their territorial waters can be recognized as high seas. According to SCMP, the Agreement includes a provision not to include disputed waters in marine protected area designations.

Moves to assert sovereignty more actively under the banner of environmental protection could also emerge. In September last year, China designated the area around Scarborough Shoal, which it disputes with the Philippines, as a national-level nature reserve, an action assessed as an attempt to tighten control over the South China Sea under the pretext of environmental protection. In the Philippines, there are also calls to use the Agreement to reinforce its claims in the South China Sea.

The exclusion of fishing and deep-sea mining, major drivers of damage to marine biodiversity, from the scope of regulation under the Agreement is cited as a limitation. While China is showing interest in deep-sea mining, Japan and the United States are also entering the field to secure rare earths. As with other UN agreements, the non-participation of the United States is also raised as a problem. The United States signed under the Joe Biden administration, but congressional ratification has yet to take place.

Marine protected areas are expected to be delineated at the end of this year at the Conference of the Parties to the Convention on Biological Diversity. In March, the United Nations will convene an international meeting to discuss establishing a scientific and technological advisory body and other matters to develop detailed rules and structures for the Agreement.