Two-Thirds of the Ocean Had No Landlord. On 17 January 2026, That Changed.

On 17 January 2026, the Agreement on Marine Biological Diversity of Areas Beyond National Jurisdiction — the BBNJ Agreement, known publicly as the High Seas Treaty — entered into force.

It had taken roughly twenty years to get there: two decades of talks, a text finalised on 4 March 2023, adoption on 19 June 2023, and then a slow accumulation of ratifications until the sixtieth arrived in September 2025.

What the high seas are

The high seas are the parts of the ocean beyond any country's exclusive economic zone. They begin roughly 200 nautical miles from shore and continue to the far side of the world.

They are approximately two-thirds of the ocean, and the ocean is most of the planet's habitable volume. By area they are the largest habitat on Earth.

Until this treaty, they had almost no biodiversity governance. There were rules for shipping, rules for some fisheries, rules for seabed mining in the Area. What there was not was a mechanism to protect life there — no way to designate a marine protected area in international waters and have it mean anything.

The high seas belonged to everyone. In practice this meant nobody was responsible for them.

What the treaty actually does

Four things, in the language of the negotiators:

1. Marine protected areas. For the first time there is a legal route to establish protected areas in international waters. This is the provision most often described as historic, and the description is fair — it did not previously exist.

2. Environmental impact assessments. Activities in the high seas that may cause substantial pollution or harm now require assessment.

3. Marine genetic resources. A framework for sharing the benefits of genetic material collected from the high seas. This was among the most contested parts of the negotiation, largely along developed/developing country lines.

4. Capacity building and technology transfer. Support for states that lack the ships, laboratories and expertise to participate otherwise.

The number that keeps moving

Reporting on ratification counts diverges, and it diverges because the count is genuinely changing.

The European Commission reported 81 Parties and 145 signatories in mid-January

1. The High Seas Alliance counted 82 ratifications as of 14 January 2026.

Both are plausibly correct on their respective dates; ratifications continue to arrive.

We are not going to publish a single number as though it were fixed. The authoritative, continuously updated count is the United Nations Treaty Collection depositary record. If you need the number today, that is where it lives.

What entry into force does not mean

This is where careful reading matters.

Entry into force means the machinery may now be built. It does not mean anything is protected yet.

Not one high seas marine protected area exists under this treaty as of this writing. The treaty creates the power to designate them. Designation requires a Conference of the Parties, proposals, scientific review, and decisions. The first BBNJ COP has yet to convene.

The treaty binds only its Parties. A state that has not ratified is not bound by it. Some significant maritime states are not yet Parties.

It does not override existing bodies. Regional fisheries management organisations and the International Seabed Authority retain their mandates. The BBNJ Agreement is explicit that it should not undermine them — a compromise that made agreement possible and that critics argue leaves the hardest conflicts unresolved.

The arithmetic behind the urgency

The world has committed, under the Kunming-Montreal Global Biodiversity Framework, to protect 30% of the ocean by 2030.

The World Database on Protected Areas reports 9.6% of the ocean as protected. The Marine Protection Atlas, which assesses protection quality rather than counting declared area, finds only 3.2% is fully or highly protected.

Both figures are current as of January 2026. They differ because they measure different things — we unpack that in The 30x30 Gap.

Getting from single digits to 30% in four years without touching the high seas is arithmetically impossible. Two-thirds of the ocean cannot sit outside the effort and leave the target reachable. That is the practical reason this treaty matters to 30x30, and it is why January's milestone was greeted with relief rather than celebration.

Why this is on AEDO1

The high seas hold an estimated ten million species, most of them undescribed. We have mapped the surface of Mars in more detail than we have surveyed the deep ocean floor.

A treaty is not a protected area. It is the permission to try to make one. Twenty years bought the permission. The next few years decide whether anything is actually protected — and that part is not yet written.