Some 10 per cent of marine species face extinction. Plastic pollution chokes reefs, industrial fishing destroys ocean habitats and deep-sea mining presents a growing threat to still little-known sea-bed ecosystems. Oceans cover three-quarters of the planet’s surface. But until now, most of what happens in them has taken place outside the boundaries of international law.

That changes on 17 January 2026, when the United Nations (UN) Agreement on Marine Biodiversity of Areas Beyond National Jurisdiction, known as the High Seas Treaty, officially enters into force. On 19 September it passed its crucial threshold of ratification by 60 states. Morocco and Sierra Leone were the 60th and 61st states to ratify, followed in the same week by Sri Lanka and St Vincent and the Grenadines.

Hailed by campaigners as a historic milestone, the agreement gives states powers to establish marine protected areas in international waters and mandates environmental impact assessments. It promises more equitable sharing of marine genetic resources, meaning for example that medicines derived from deep-sea species should benefit everyone rather than just select corporations and states.

The treaty comes at a critical time. New research shows the world’s oceans have failed a key planetary health check. Ocean acidification – caused by rising carbon dioxide levels and bringing potentially devastating impacts on key species such as coral and shellfish – has passed a critical threshold. It’s become the seventh of nine planetary boundaries that the stability and resilience of the Earth’s systems depends on to be breached.

Decades of advocacy rewarded

The treaty is a civil society success story: it became a reality thanks to over a decade of civil society efforts.

The UN began addressing ocean governance gaps in 2004 through an ad hoc working group that met repeatedly until 2011, when states finally agreed on four key areas for the treaty: marine genetic resources and benefit-sharing, marine protected areas, environmental impact assessments and capacity strengthening for global south countries.

As diplomatic discussions intensified, civil society organisations came together in the High Seas Alliance to coordinate their pressure. Founded in 2011, the coalition grew to include over 50 organisations.

Formal negotiations began in 2017 and continued through five intergovernmental conference sessions between 2018 and 2023, interrupted by COVID-19. Throughout these negotiations, the High Seas Alliance provided technical expertise, held governments accountable to ambitious environmental standards and kept up the pressure for strong protective measures. The coalition’s tireless advocacy helped ensure the treaty includes robust provisions for marine protected areas and meaningful benefit-sharing arrangements.

Youth movements injected much-needed urgency into diplomatic proceedings. GenSea, a movement connecting over 1,500 ocean advocates aged between 13 and 25 in more than 100 countries, brought the perspectives of those set to benefit from a future of healthier oceans.

Once the text was finalised in March 2023, things happened quickly in the often slow-moving arena of global governance: the treaty was formally adopted in June 2023, opened for signatures three months later and hit the 60 ratifications needed to enter into force in just two years.

UN Secretary-General António Guterres called the passing of the ratification threshold a historic achievement for the ocean, emphasising that the health of oceans is humanity’s health. It’s also a win for multilateralism at a time of growing contestation of the notion of a rules-based international order.

Small island states lead but major powers lag

Small island states – where the health of oceans and climate impacts are hard-to-overlook issues – took the lead in bringing the treaty into force, with Palau ratifying first in January 2024. But ratification patterns have revealed some stark geopolitical divisions.

To date, 143 states have signed the treaty, which is a first step – but only 73 have ratified it. France’s President Emmanuel Macron championed the 60-ratification goal when the third UN Ocean Conference took place in Nice, France in June. But despite European Union (EU) backing, European support is patchy and influential states such as Germany and the UK still haven’t ratified.

The USA’s absence looms large. Despite signing under the Biden administration, ratification has stalled and seems highly unlikely with Donald Trump in office, particularly given his government recently ordered the fast-tracking of deep-sea mining permits.

Other major fossil fuel producers, including Iran, Russia and Saudi Arabia, remain outside the framework, as they haven’t signed the treaty. Neither has Japan. Of the BRICS group – a club of 10 major non-western economies – only Indonesia has ratified. States that are refusing to engage may be motivated by a reluctance to impose limits on resource extraction or a rejection of multilateralism – or both.

Implementation battles ahead

The treaty’s entry into force isn’t the finish line – it should be the beginning. States now have just under four months to prepare for the treaty’s entry into force in January. In late March and early April, a preparatory commission will make its recommendations. Later in 2026, the first conference of parties will face the critical task of translating the treaty into functional protection.

Urgent action is needed to reach the goal of conserving 30 per cent of global oceans by 2030, adopted by close to 200 states as part of the 2022 Global Biodiversity Framework. Chile has taken the lead with the first proposal for a fully protected international area covering the Salas y Gómez and Nazca Ridges, a biodiversity hotspot where scientists recently discovered 170 new marine species. Others could follow. Chile is also competing with Belgium to host the treaty’s secretariat, signalling serious institutional commitment.

However, there are major challenges ahead. Enforcement issues will test institutional frameworks from day one, while the financing question grows more urgent as global south states need financial support and technology transfers to be able to participate and benefit fully.

New battle lines have been drawn at recent preparatory meetings as some states want the power to prevent civil society, Indigenous peoples and scientists submitting written inputs at future conferences. This would make mockery of the treaty’s transparency commitments. The knowledge of Indigenous and coastal communities is invaluable in managing complex marine ecosystems – but they need to be given a real seat at the table.

Meanwhile, climate realities add urgency as ocean warming, acidification and sea level rise create cascading effects that narrow the window for effective intervention. With the ratification threshold passed, it is now time for action.

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