High Seas Treaty Poised to Take Effect as Nations Prepare Ratifications at U.N. General Assembly

A landmark international agreement to protect biodiversity on the high seas is on the verge of becoming binding international law after more than 100 countries negotiated terms in 2023, advocates said. The U.N. High Seas Treaty requires 60 ratifications to trigger a 120-day countdown to entry into force, and diplomats and campaigners expect that threshold to be met during the opening week of this year’s U.N. General Assembly, when leaders and ministers gather in New York and can personally deposit instruments of ratification.

The treaty would create a legal framework to establish marine protected areas in international waters beyond national 200-mile exclusive economic zones, and to strengthen management of activities such as fishing, shipping and exploration. The high seas together make up nearly two-thirds of the ocean and hold some of the planet’s most diverse and least-studied ecosystems, according to scientists and advocacy groups.

Advocates say the treaty is a major step toward meeting scientific calls to protect at least 30% of the world’s oceans to sustain long-term ocean health. Currently, about 8% of the ocean is formally designated as marine protected area, and recent assessments estimate that less than 3% is effectively protected. The U.N. agreement is designed to enable countries to negotiate and designate high seas marine protected areas and to develop mechanisms for benefit sharing, marine research cooperation and capacity building for developing states.

Lisa Speer, who has spent two decades working on ocean protection and served as a lead advocate during the 2023 negotiations, said the approaching milestone was the result of persistent international diplomacy. Speer, director of international oceans at the Natural Resources Defense Council, described the moment as both a win for ocean conservation and for multilateralism. "The French have already agreed to bring the Champagne to New York," she said, referring to France's role in the final ratification push.

The treaty will not itself set specific protected sites or management rules, diplomats and advocates caution, but will establish the juridical and institutional foundation for those negotiations. Once in force, it would allow member states to propose, negotiate and adopt the first generation of high seas protected areas and to address cross-border issues that have overwhelmed a fragmented patchwork of existing governance.

The High Seas Alliance, a global partnership of scientists and environmental organizations, has identified eight priority sites that could be among the first candidates for protection. One example is the Lost City hydrothermal field in the mid-Atlantic, a system of chimney-like mineral formations that supports a high proportion of species found nowhere else on Earth. Scientists say approximately 60% of species discovered at Lost City are endemic. The site and others face mounting pressure from activities including exploratory deep-sea mining, fishing and shipping.

Proponents say the treaty could also help govern the commercial use of genetic resources from the high seas by creating frameworks for sharing benefits derived from marine genetic materials, and by providing programs to help developing countries access marine science and technology. The agreement would enhance cooperation on conservation and sustainable use, a capability that advocates say is absent in many areas beyond national jurisdiction.

The campaign to secure ratifications has continued despite uneven political environments in several major maritime nations. Environmental advocates point to recent policy rollbacks in the United States and elsewhere on climate and environmental protections, saying that such domestic decisions have complicated global progress. Nevertheless, campaigners note steady international support from a broad range of countries and civil society groups.

Negotiators and advocates caution that the treaty’s coming into force will mark the start of intensive diplomatic and technical work rather than an endpoint. Many procedural and substantive questions remain to be resolved: how to delineate and monitor protected areas, how to integrate the treaty with existing regional fisheries and shipping agreements, and how to balance scientific access with conservation goals.

Speer said the treaty’s passage would open the door to years of drafting management measures and negotiating specific protections, and urged continued public and political engagement. "The reward for hard work is more hard work," she said. "There is plenty of that ahead."

If the 60-ratification threshold is reached during the U.N. General Assembly week of Sept. 22–26, the 120-day countdown to entry into force will begin, allowing countries and scientific bodies to move toward proposing the first protected areas on the high seas. Advocates say those early designations will test the treaty’s ability to conserve remote and vulnerable marine ecosystems and to set precedents for future international ocean governance.