Scientists and advocates for marine conservation are hailing the creation of a new treaty to protect nature on the high seas – the vast ocean expanse that lies outside any country’s territorial waters and comprises about 50 per cent of Earth’s surface.

More than 190 countries were involved in negotiating the pivotal agreement, which represents the culmination of nearly 20 years of multilateral efforts. Success was reached on Saturday night after a two-week meeting at United Nations headquarters in New York, including a final 36-hour-long session during which prospects for success were uncertain.

“It really was touch and go,” said Susanna Fuller, vice-president of operations and projects for the Nova Scotia-based environmental group Oceans North, who was present as an observer at the talks, “but there was a lot of goodwill in the room.”

Once ratified by member states, the treaty will provide countries, for the first time, with a legally binding mechanism for conserving species and ecosystems in international waters and managing activities that could negatively affect ocean life.

It will allow for the setting up of marine protected areas that cover large swaths of the high seas – a step that is seen as crucial for achieving the target of protecting 30 per cent of the planet for nature by 2030, as laid out in the framework on global biodiversity that was established last December in Montreal.

Canada, which has coastlines on three of the world’s oceans, has lately increased its commitments to protecting marine waters under its control. It has also pushed for the new treaty as part of a “high-ambition coalition” of countries focused on biodiversity beyond national jurisdiction.

The new treaty opens the possibility of connecting some countries’ marine protected areas with the global ocean at large, something that biologists say is especially important for migrating species, including sea turtles, whales and many millions of fish.

Other aspects of the treaty, whose final text has yet to be translated and released, include standards for environmental-impact assessments of ocean activities and provisions for the fair and equitable use of the ocean’s genetic resources.

“This will help ensure that all countries of the world can take part in the conservation and sustainable use of the high-seas global commons that belongs to all of us and yet none of us at the same time,” said Julian Jackson, a senior manager with the Pew Charitable Trusts’ campaign for protecting ocean life on the high seas.

Significantly, the treaty is the first international agreement that encompasses biodiversity in the deep ocean, a part of the biosphere that remains poorly understood though it plays a key role in the transport of carbon and nutrients around the planet.

“When we think about the high seas, we think about the surface of the ocean – that’s where the fish are – but we don’t really think about the important connections that exist with the deeper waters,” said Anna Metaxas, an ocean scientist at Dalhousie University in Halifax who specializes in deep ocean life.

Dr. Metaxas, who is currently on sabbatical in Australia, is a member of the Deep Ocean Stewardship Initiative, a collaboration whose aim is to ensure that ocean policy is guided by sound science.

She said news of the agreement quickly circulated through her professional network on Saturday.

In an interview with The Globe and Mail, she noted that one area where the new treaty could come into play involves proposals to stimulate the growth of algae on the open sea to take up carbon from the atmosphere for climate-change mitigation. In such a scenario, the carbon would then become residue at the bottom of the ocean.

“These approaches are a little bit scary to me because if they scale up, it will really quite profoundly change how much carbon the deep sea floor receives,” Dr. Metaxas said. “I think it will be important to use the treaty to make sure that what we’re doing is properly evaluated.”

It will likely take another two to three years for most countries to ratify the treaty, said Dr. Fuller of Oceans North.

Other steps include setting up a location where the treaty will be administered and establishing a new conference of the parties (COP) with regular meetings aimed at developing the agreement in detail, similar to the process that governs international climate and biodiversity talks.

Dr. Fuller called the treaty “imperfect” in the level of environmental protection it stipulates but added that anything stronger would likely have made a deal untenable.

And after so many years of setbacks and stalled talks, it was a relief to have an agreement fall into place through the co-operation of so many countries, particularly at a time of elevated international tension.

“It’s a very powerful moment,” Dr. Fuller said. “And those moments are few and far between.”

The Globe and Mail, March 5, 2023