They glide through crystalline blue seas—sea turtles, whales, dolphins, sharks, manta rays, and a dazzling array of other marine life—often traveling thousands of miles on ancient migratory routes to gather, feed, and breed. Much of their travel is across the high seas, the world’s vast ocean beyond the jurisdiction of any government, an area that also faces growing threats from overfishing, illegal fishing, pollution, marine debris, warming waters, noise disturbances, and more.
But soon the international community should have better tools for addressing those threats: On June 19, United Nations member countries adopted a treaty to safeguard the high seas, in large part by establishing a mechanism for the creation of marine protected areas (MPAs) to limit or prohibit destructive activities beyond the blue horizon.
The agreement is a historic step forward for ocean protection. The high seas harbor a stunning range of biodiversity, from marine mammals to deep-sea corals, hydrothermal vents, phytoplankton, and immense schools of fish. And because the high seas cover two-thirds of the ocean, establishing safeguards there is necessary to achieving the global goal of protecting 30% of the ocean by 2030, a target known as “30 by 30,” which the United Nations Convention on Biological Diversity adopted last December. Currently, less than 1% of high seas waters are highly protected.
To achieve this desperately needed deal, delegates went into overtime on the last night of the final two-week negotiating session earlier this year—working 36 hours straight to finalize the treaty text in preparation for the June vote.
Delegates, hungry and exhausted from the slog, were determined to achieve a deal rather than walk away from the table. And on March 4 at 9:25 p.m., Rena Lee of Singapore—the president of the negotiations—announced that delegates had finally found agreement, saying, “The ship has reached the shore.”
Lee’s announcement sent the delegates into applause and showcased the value of unwavering focus and persistence to take action for the ocean.
“Ocean scientists have long cautioned us about threats to the bounty of life in the high seas, and now, finally, the U.N. has responded with a once-in-a-generation treaty to protect these areas from harmful human activities,” says Elizabeth Wilson, senior director of environmental policy at Pew.
Some form of the treaty has been under discussion for two decades, and Pew has been at the forefront of the effort for much of that time.
That history starts in 2013, when Pew led the creation of the Global Ocean Commission, a body that included heads of state, business and political leaders, and nongovernmental organization representatives. The commission focused on how to restore the ocean to its pre-industrial age health, ensuring its resilience, and promoting fair and equitable governance of the global marine environment.
The commission issued a report in 2014 that highlighted the factors—from climate change and biodiversity and habitat loss to declining fish stocks—driving the decline of the ocean’s health and proposed ways to address them, including through a treaty to safeguard the underprotected high seas. Because those waters are part of the global commons, governments and international institutions had scant legal mechanisms to increase conservation.
The research also showed that the high seas help to regulate global air temperatures and slow the impact of climate change—including on land—by absorbing and storing excess carbon dioxide from the atmosphere.
The commission report estimated the economic value of removing this carbon from the atmosphere at between $74 billion and $222 billion per year. In comparison, a 2018 U.N. Food and Agriculture Organization report estimated the gross value of the catch in high seas fisheries at $7 billion to $16 billion a year. Industrial fishing fleets work in more than half of these ocean areas, and over one-third of the fish stocks they target are overexploited—up from 10% in 1974.
The high seas have an average depth of more than 2.5 miles, but even species that live in those inky depths face threats from human activity. Fishing technology now enables fleets to drop lines or drag nets thousands of feet below the surface, threatening animals such as deep-sea sharks, which are slow to reach sexual maturity and produce young only sporadically, making them especially vulnerable to overfishing.
In its December 2022 assessment of biodiversity, the International Union for Conservation of Nature found that human activity is having a devastating impact on the ocean and that 10% of all marine species are at risk of extinction.
All of this leaves the ocean with very few truly wild places completely free of the influence of humankind. Of equal importance, the human impact on the high seas threatens to disrupt the ecological balance of the ocean, a scenario that could not only imperil marine life but also irrevocably alter the climate and food security worldwide.
In 2014, Gina Guillen-Grillo, then Costa Rica’s legal adviser to the U.N., led a group of United Nations delegates and ocean advocates to Playa Langosta along her home country’s rugged west coast to watch rare leatherback sea turtles come ashore to nest, as the creatures have done since time immemorial.
Many of the delegates, who had gathered in the town to refine a strategy for advancing high seas protections, were eager to witness a remarkable wildlife event. Instead, they found a quiet, empty beach, with no turtles in sight.
Leatherback turtles spend most of their lives on the high seas and travel to coastal areas to lay their eggs. Despite efforts to conserve this endangered species, Pacific leatherback turtle populations fell by more than 95% from 1989 to 2019, a decline scientists attribute largely to deaths as bycatch in the pelagic longline fishery. Although protecting nesting areas on coastal beaches is vital to leatherback turtles’ recovery, it is equally critical that these creatures be protected from harmful fishing practices in their high seas habitat.
And while scientists can’t say for sure why the turtles didn’t come ashore in Playa Langosta that night in 2014, the experience nonetheless drove home the importance—and urgency—of the delegates’ work.
“Back then a lot of people at the U.N. were saying, ‘There are no gaps [in ocean governance], so why do we need a treaty?’” says Guillen-Grillo, who is now Costa Rica’s director general of foreign policy. “But many of us knew the science. Leatherback turtles have to overcome a lot to survive, and we were up against a lot of opposition at the U.N., so by the end of the four-day meeting, we decided to call ourselves the Leatherbacks, and to support each other in negotiations for a treaty.”
The experience redoubled the delegates’—and Pew’s—commitment to a treaty that enabled the creation of MPAs in international waters.
At the time, MPAs were gaining traction as a reliable way to protect existing biodiversity and help even heavily degraded areas recover. Research on protected areas in domestic waters showed that MPAs yield the greatest conservation benefits when they are large, highly protected, isolated, well enforced, and long-standing. Benefits increase exponentially when all five features are in place.
One 2018 analysis found that the average biomass of fish within these marine reserves is 670% greater than in adjacent unprotected areas and 343% greater than in partially protected MPAs. Well-designed marine reserves can lead to larger fish populations beyond the boundaries of the protected area, either from “spillover”—the migration of adult fish from the MPA—or the dispersal of larvae spawned within it. This means, somewhat counterintuitively, that closing large areas to fishing can, and often does, result in much more productive fisheries.
In the high seas, networks of MPAs that create meaningful links across habitats would benefit not only highly migratory species but, by extension, the health of the entire ocean, including coastal areas—and the species like leatherback turtles that depend on access to shore.
As formal negotiations got underway at the U.N. in 2018, Pew worked hard to highlight the importance of the treaty, which included an advertising campaign in New York City during the first negotiating session as well as a sustained campaign to keep disparate governments informed and motivated to support the effort.
Pew engaged in a multiyear collaboration with scientists from around the world to help identify which high seas areas would benefit most from protection once the treaty is in place.
Pew’s contributions to the treaty negotiation process expanded far beyond analyzing and supporting critical scientific research. The team also organized or presented at hundreds of workshops to help fill knowledge gaps and address important unresolved issues; engaged with high-level political leaders around the world to secure commitment for an ambitious treaty; and worked to make and maintain relationships with the government delegates engaged in the technical detail of negotiations, many of whom regularly consulted Pew for advice.
“While the impact of our work is sometimes intangible, there were definite moments where we knew our efforts paid off—like when delegates used our suggested language verbatim on the U.N. floor during negotiations,” says Pew’s Nichola Clark, who has been heavily involved in the treaty development since 2016.
Pew was also instrumental within the High Seas Alliance, a coalition of more than 50 nongovernmental organizations working toward an ambitious treaty. In addition to serving on its steering committee, Pew leads the alliance’s high seas MPA working group, which identified the coalition’s key priorities and strategies for the MPA chapter of the negotiations.
These years of effort culminated in a March 2020 report that highlighted 10 such high seas areas. These include the Salas y Gómez and Nazca Ridges, submarine mountain ranges in the southeastern Pacific Ocean off the coast of Chile that contain some 110 seamounts. Also on the list are the Lord Howe Rise, a deep-sea plateau east of Brisbane, Australia, that serves as a feeding ground for numerous endangered species, and the South Tasman Sea off New Zealand, which is among the most productive areas of the high seas and a way station for humpback and southern right whales. Most recently, Pew has turned that March 2020 report into an interactive web tool that allows users to create their own high seas protection hot spot map, tailored to their individual conservation goals.
All of Pew’s and the alliance’s key priorities for the MPA chapter were successfully achieved in the final treaty, including a provision that allows MPAs to be adopted by a three-fourths majority vote when consensus can’t be reached. It now will require 60 nations to ratify the agreement. It’s unclear if the U.S. Senate will ratify the treaty—a two-thirds majority vote is required within that body to do so. If that vote failed, the U.S. would give up its right to propose or vote on high seas MPAs and participate in other particulars of the treaty.
“This treaty is needed now both because of all the stressors our ocean is facing and because U.N. members have committed to 30 by 30,” says Liz Karan, who has led Pew’s work on the high seas treaty since 2014. “And it would be really hard to hit that goal without high seas protections.”
As with any international agreement, hard work lies ahead on the high seas treaty. Before ratifying it, many governments must first amend their national laws to ensure that they can meet all of the requirements set out in the new treaty. But for the first time a framework is now in place to achieve what many would have thought implausible: safeguarding an immense portion of the planet that most people will never see, but one that influences the lives of virtually everyone on Earth.
“We think of the ocean and the high seas as limitless—that they can take whatever we throw at them,” Karan says. “But as we’re seeing with plastics pollution and overfishing and climate change, the ocean has limits, and this is the only mechanism to help recover this ecosystem. Most other ocean governance rules are about managing what’s being taken out of our seas. This treaty is about protecting what’s already there.”
John Briley is a Trust staff writer.
Lead photo: Fishing with a purse seine net on the high seas. piola 666/Getty Images