What is the UN high seas treaty and will it save the world’s oceans?

After a decade of negotiations and a final two-week marathon of round-the-clock talks, countries around the world have agreed a new treaty to protect the world’s high seas.

The agreement, struck late on 4 March in New York, establishes a legal framework that will finally allow countries to designate international waters as protected areas for marine life, if agreed by consensus.

But although campaigners welcomed the news as a “historic day for conservation”, they warned it marked only the start of a long journey to ensure the world’s oceans are adequately protected for future generations.

What are the high seas?

The “high seas” refers to oceans that lie in international waters, meaning they aren’t subject to any rules or regulations set by national governments. About two-thirds of the world’s oceans fall into this category, covering half the planet in total. Few legal protections exist to govern activity on the high seas, particularly where environmental issues are concerned.

“The high seas belong to everyone; juridically, they’re seen as ‘the common heritage of mankind’, just as space or the moon,” said Frida Bengtsson at Stockholm University in Sweden, in a statement.

International waters are home to hotspots of marine biodiversity and areas of unique habitats, such as deep-sea coral gardens and underwater mountains. But these ecosystems are under increasing stress, and many ocean species, including sharks, rays and whales, are under threat of extinction due to overfishing and climate change. For years, marine biologists have argued stricter environmental protections are needed to give oceans and their inhabitants a fighting chance of survival.

What is the high seas treaty?

Formally known as the Biodiversity Beyond National Jurisdiction treaty, the agreement will provide the first legal framework to apply environmental protections to the high seas.

Nations have been discussing this treaty since 2004, and in the past year alone have tried three times to get the agreement over the line.

But the talks have proved contentious. Nations have long argued over how to split the benefits of genetic resources in international waters, which can prove lucrative for pharmaceutical and cosmetics industries. Funding and fishing rights were also major sticking points.

Since the COP15 biodiversity summit in Montreal, Canada, last year, pressure has been mounting on member states to reach an agreement that will allow ocean conservation work to move forward. Environmental groups such as Greenpeace warned that without a treaty governing the high seas, it would be impossible to achieve crucial targets agreed at COP15, such as the goal to protect 30 per cent of the world’s land and sea by 2030, known as 30 by 30.

A concerted diplomatic effort by the so-called high ambition coalition, which included the European Union, the US, the UK and China, was also crucial to unblocking a deal. Promises of further funding to support action also helped: on 2 March, the EU announced €816.5 million (£723 million) worth of commitments for ocean protection.

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What does the treaty achieve?

The long-awaited treaty will prove “crucial for addressing the triple planetary crisis of climate change, biodiversity loss and pollution”, UN Secretary-General Antonio Guterres said in a statement.

One of the most critical elements of the document is its provision to allow the creation of international marine protected areas, where activities such as industrial fishing or deep-sea mining could be restricted. The move is seen as vital for enabling the world to meet the 30 by 30 target.

Greenpeace said the new treaty was a “historic day for conservation” and a workable starting point for achieving the 30 by 30 goal. “We can now finally move from talk to real change at sea,” said Laura Meller, oceans campaigner for Greenpeace Nordic, in a statement.

The treaty also includes a plan to overhaul environmental impact assessments, which calculate the potential damage of human activities on the high seas. Under the treaty, all nations will need to follow consistent ground rules for carrying out these assessments.

There are provisions to share the benefits of genetic materials from the oceans, and regular “COP” summits will take place to ensure the treaty is being adequately enforced.

What happens next?

Reaching agreement on the text of the treaty is a major breakthrough, but it is only the start of a long process of ratification and implementation.

The treaty needs to be formally adopted by member states, then ratified by at least 60 countries before it will enter force. Similar international treaties, such as the Paris climate agreement, took almost a year to be signed and ratified.

There will also be further questions to iron out in subsequent meetings, such as how marine protected areas will be managed, connected and enforced.

“The treaty lays down broad commitments to protect 30 per cent of the high seas. Which parts will be protected, and how strictly, remains to be decided,” says marine biologist Helen Scales.

“My hope is that the treaty will implement meaningful protection, that is strictly safeguarding areas from all potential sources of harm.”