The ocean is incredibly important for us and all life on Earth. We are interconnected in so many ways, and most of all dependent on the ocean for our well-being. The ocean regulates our climate. It absorbs 25% of carbon emissions, produces half of the oxygen and stores 90% of excess heat in our climate system. [1] It provides us with 15% of our animal protein and nearly half of the global population depends on the blue economy for their income. [1]
More than half (65%) of the ocean’s surface belongs to the high seas – those areas of the ocean that lie beyond national jurisdiction. [2] In volume the high seas even make up 90% of the ocean, and they take care of 59% of ocean carbon sequestration. [2,3] Did you know that the ocean is a carbon sink (meaning that it absorbs and stores carbon), amongst other processes thanks to tiny floating organisms called phytoplankton? Phytoplankton are, like plants on land, primary producers that use carbon dioxide to make their own sugars. They sustain the vast biodiversity that we know (and don’t know yet) in the high seas! The high seas are home to many organisms, from the smallest to the largest!
Since the high seas, and the biodiversity it contains, essentially belong to no one, their protection is a common responsibility that we all share. Today, less than one percent of the high seas are protected, mainly because a globally agreed mechanism for doing so was missing. [3] However, efforts to fill this policy gap already started two decades ago. [4]
It all started in 2004, when the United Nations held its fifth meeting of an Open-ended Informal Consultative Process on Oceans and the Law of the Sea. Among the discussion points was “New sustainable uses of the oceans, including the conservation and management of the biological diversity of the seabed in areas beyond national jurisdiction”. That same year, the United Nations General Assembly decided on a working group to further study this challenge.
Between 2006 and 2015, the working group held nine sessions and delivered recommendations on the scope, parameters and feasibility of an international agreement under the United Nations Convention on the Law of the Sea. Following the recommendations, the General Assembly decided in 2015 that an international and legally binding instrument would be developed! A long but worthy process started!
A Preparatory Committee was established to make recommendations for a text, and at its fourth session in 2017 the Committee delivered a report to the General Assembly. The next year, the General Assembly decided that an Intergovernmental Conference would be held, and it was followed by five sessions. During the last session, on 19 June 2023, 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) - also known as the High Seas Treaty - was adopted by consensus!
On 20 September 2023, the High Seas Treaty opened for state signatures, and by signing, a country indicated their willingness to ratify the treaty and consent to the new international law. To officially enter into force, 60 ratifications were needed, and on 19 September 2025 this milestone was reached! By now, more than 60 countries have ratified the Treaty. You can keep track of which countries have signed.
A period of 120 days bridges the 60th ratification to the official entry into force. On 17 January 2026, the High Seas Treaty will thus become the first legally binding agreement to protect biodiversity beyond national jurisdiction!
This is a great outcome for all of the work that has been done. The international community showed that hard work and cooperation pays off! This is only the beginning for the protection of the high seas. So, stay tuned!
Below are a few resources that you can browse to learn more about the high seas and its biodiversity:
- Read the article in Frontiers for Young Minds which explains the role of phytoplankton: ‘Tiny Phytoplankton: the Most Powerful Organisms of the Ocean’.
- Have a look at Nausicaa’s webpage on the high seas which explains what the high seas are, where they begin, who they belong to and why we should care about them.
- Learn about the BBNJ Agreement’s four pillars with our previous Map of the Week on Biodiversity Beyond National Jurisdiction.
- Read Nausicaa’s article on the ratification of the High Seas Treaty, which provides a brief history of the High Seas Treaty and the next steps.
- Explore the United Nations webpage dedicated to the BBNJ history that allows you to learn about the full journey from discussions on the topic in 2004 to the adoption of the BBNJ Agreement in 2023.
- Check the High Seas Ratification Tracker that lists all countries that have ratified the Treaty and has a countdown to the official date on which the Treaty enters into force.
- Read the IUCN press release on the 60th ratification, which includes reactions from, among others, Ambassador Rena Lee, President of the BBNJ Treaty Intergovernmental Conference.
The data in the map is provided by the Copernicus Marine Service.
[1] https://www.un.org/en/desa/5-reasons-you-should-care-about-our-ocean
[2] https://www.nausicaa.fr/en/the-ocean-magazine/what-are-high-seas
[3] https://www.nature.com/articles/d41586-025-01665-0
[4] https://www.un.org/bbnjagreement/en/bbnj-agreement/history