Most of the ocean belongs to no one — but is the responsibility of everyone.
Nearly two-thirds of Earth’s seas lie beyond the jurisdiction of any nation, and in these “high seas” are a bounty: more than 90 percent of ocean habitat and some of the highest reservoirs of biodiversity on the planet.
Yet only about 1 percent of the high seas are currently protected, despite threats from overfishing, plastic pollution and climate change — with seabed mining looming in the near future.
A landmark United Nations treaty to protect the high seas aims to change that — it just has to be ratified by countries. First adopted in 2023, the high seas treaty opens the door to marine protected areas in the waters beyond national jurisdictions. Only 31 nations have ratified so far so it has yet to go into effect.
Global leaders will gather for the third United Nations Ocean Conference (UNOC) in France this week, and ocean advocates hope it will provide momentum to reach the 60 countries needed to ratify the treaty.
Monica Medina, Arnhold Fellow at Conservation International, recently spoke with Conservation News about this decades-in-the-making treaty, and what is at stake.
Conservation News: Let’s start with some scene setting — why is the high seas treaty historic?
Monica Medina: The high seas make up nearly half of the planet’s surface — yet only a sliver of that vast and largely unexplored expanse has been protected. And since no country controls these waters — it can be like the Wild West out there. That’s why the high seas treaty is so critical — it’s meant to step up and fill that void.
And it’s been years in the making, going all the way back to the 1982 UN Law of the Sea Convention. Also known as the Law of the Sea Treaty, it’s viewed as the “constitution” of the ocean, and it enshrines the belief that there are areas of the ocean that we must protect as a human race to survive.
And it couldn’t come at a more important time as isolationist thinking is on the rise and multilateralism is under question. This week’s UNOC is a crucial moment for the world to step up and say, yes, we are still working together and this is a priority.
Where does the treaty stand ahead of UNOC?
MM: So far, approximately 30 countries have ratified the treaty, so we’re about halfway there. It’s a bit of a disappointment that we’re not further along, but I am optimistic that events like UNOC will give us momentum. In just the last two months leading up to the conference, 10 new countries have signed on. And I expect more will announce ratification while we are at the conference.
Unsurprisingly, it takes time to ratify a treaty, which is a legally binding agreement. Because the high seas exist outside of any one country’s jurisdiction, that’s necessary as all countries need to agree to it. Without that support, marine protected areas in the high seas run the risk of becoming “paper parks” without any real enforcement or protection.
Two things give me hope that it will enter into force soon. For one, on the first day the treaty was open for signature with the intent to ratify, nearly 100 countries signed up immediately. And, the first preparatory session for implementing the treaty has already taken place, where representatives have hashed out details like potential areas to target for protection and how to approach funding.
There are several other important environmental meetings coming up this year, including COP30 in Brazil. These events are pressure points that create deadlines for countries to step up and get the job done.
What’s at stake?
MM: Dr. Jane Lubchenko, a renowned marine biologist and former head of the National Oceanic and Atmospheric Administration (NOAA), wisely said that oceans are too big to ignore. In the past, we often thought of them as giant, vast places that could never be overexploited. Look at the headlines today about plummeting fish populations, climate change and runaway plastic pollution and it’s crystal clear: they're not limitless.
Protected areas are our best tool to restore and defend oceans. In fact, we can’t reach our global goal of “30 by 30”— which nearly every country on Earth, excluding the United States, has agreed to — to protect 30 percent of the planet’s land and seas without the high seas. It's really important to target places that still haven't had the heavy footprint of human impact and try and hold on to them. Many of those places are in the high seas — and they’re under threat from illegal fishing and the potential for mining precious metals on the seafloor, at great harm to the environment.
Less talked about, but also important is the bioprospecting angle of the treaty. What does that mean? It’s essentially about the organisms in the high seas and their potential for scientific breakthroughs — whether that’s developing a plastic replacement or new medical drugs that save lives. We are only just beginning to figure out how to realize this part of the treaty, but it ensures that these new genetic discoveries will be cataloged and shared across the globe so the whole world can benefit because what lies in the high seas belongs to everyone and is the common heritage of mankind.
What’s next?
MM: Once the treaty is ratified, a 120-day countdown to it taking effect begins. Within a year, the first meeting of the UN Conference of the Parties will take place, where countries will agree to measures to protect the high seas, like marine protected areas and how to fund these efforts.
Conservation International has been focused on supporting the treaty’s ratification and implementation and how to put this legal framework into practice as a founding member of the Blue Nature Alliance.
We are also leaders of the Coral Reefs of the High Seas Coalition, which has already identified several high seas areas as priorities for protection. One of these is the Salas y Gómez and Nazca ridges, a series of deep-sea mountain ranges off the coasts of Peru and Chile. It’s a migration corridor for sharks, whales and turtles — and home to reef-building corals, which support thriving underwater gardens. Moreover, these waters have deep cultural significance: Polynesian voyagers crisscrossed them for thousands of years as they explored from the West Pacific to Rapa Nui.
The high seas treaty has been a long time coming — we are so close to it becoming a reality. I’m hopeful that this conference gives us the boost we need to cross the finish line and get to work.
Mary Kate McCoy is a staff writer at Conservation International. Want to read more stories like this? Sign up for email updates. Also, please consider supporting our critical work.
