'High-Seas Treaty' to protect marine biodiversity ratified, in effect from January 2026

A critical mass of United Nations (UN) member countries have ratified a treaty that will protect marine biodiversity in oceanic regions that fall outside of national jurisdictions.

In total, the treaty takes in roughly 60% of the world’s oceans and aims to set aside 30% of the planet’s waters as marine protected areas, and, with its ratification, will come into effect as a binding global regulation on 1 January 2026.

The treaty, formally known as the Agreement under the United Nations Convention on the Law of the Sea on the Conservation and Sustainable Use of Marine Biological Diversity of Areas beyond National Jurisdiction (BBNJ agreement), was adopted by UN Member States in June 2023 after nearly two decades of negotiations.

Adopted by the Intergovernmental Conference on Marine Biodiversity of Areas Beyond National Jurisdiction, the High Seas Treaty aims at "taking stewardship of the ocean on behalf of present and future generations, in line with the Convention on the Law of the Sea," according to the UN.

The agreement contains 75 articles that aim to regulate responsible use of the marine environment, maintain the integrity of ocean ecosystems, and conserve the inherent value of marine biological diversity.

"The ocean is the lifeblood of our planet, and today, you have pumped new life and hope to give the ocean a fighting chance,” UN Secretary-General António Guterres told delegates in June 2023.

At the same time, on X (formerly Twitter), Greenpeace International called the High Seas Treaty "the biggest conservation victory ever".

The International Maritime Organization (IMO), the UN’s specialised body for regulation of shipping, welcomed both the adoption and ratification of the treaty.

At the time of the treaty’s adoption, the International Chamber of Shipping (ICS), which was involved in the treaty’s negotiations process from 2016, highlighted the role of the IMO, the International Maritime Organization (IMO), in defining the detail of the treaty.

“From the shipping industry’s perspective, the High Seas Treaty agreement takes into account IMO’s role and is intended to cover gaps in ocean governance. It will help ensure emerging high seas industries will be as well-regulated as shipping is by IMO, with the detail of any measures that may be needed for ships to be discussed and agreed at IMO,” ICS policy manager (legal) Emily Rowley said in 2023.

“Fundamentally, the agreement should enhance co-operation and co-ordination between UN agencies and other global and regional regulators of activities on the high seas. This will foster a holistic approach to the protection of marine biodiversity and ecosystems in areas where no one state is responsible for preserving them.”

Work on the BBNJ agreement originated in the UN in 2004, and spanned nearly 20 years. The treaty is linked to the United Nations Convention on the Law of the Sea (UNCLOS), which was was adopted in 1982 and entered into force in 1994, establishing rules governing the use of the oceans and their resources. The treaty established the geographical region known as the high seas, which is a global commons, usable by all countries for fishing, shipping and research. To date, only 1.2% of this enormous area has had any form of environmental protection. 

The International Seabed Authority (ISA) that oversees licensing for activities such as deepsea mining told the BBC in 2023 that "any future activity in the deep seabed will be subject to strict environmental regulations and oversight to ensure they are carried out sustainably and responsibly".

A statement from UN secretary general Antonio Guterres in March 2023 said the High Seas Treaty is crucial for addressing the triple planetary crisis of climate change, biodiversity loss and pollution.

“This action is a victory for multilateralism and for global efforts to counter the destructive trends facing ocean health, now and for generations to come,” the UN secretary general’s statement said.