By Catrin Einhorn

NEW YORK – After two decades of planning and talks that culminated in a gruelling race over the past few days in New York, a significant majority of nations agreed on language for a historic United Nations treaty that would protect ocean biodiversity.

As marine life faces threats from climate change, overfishing, the possibility of seabed mining and other dangers, the treaty would make it possible to create marine protected areas and enact other conservation measures on the “high seas,” the immense expanse of ocean covering almost half the world.

“Today the world came together to protect the ocean for the benefit of our children and grandchildren,” said Monica Medina, an assistant secretary of state. “We leave here with the ability to create protected areas in the high seas and achieve the ambitious goal of conserving 30% of the ocean by 2030.”

The open oceans of the world have no international body or agreement with a primary focus of protecting marine biodiversity. If enacted, this treaty would change that.

However, there is still a way to go before the treaty can take effect. The next major step would be for countries to formally adopt the language, which was settled Saturday night. Then, nations would need to ratify the treaty itself, which often requires legislative approval.

Here’s a look at this past week’s agreement, what it means and what might happen next.

What are the ‘high seas’?

Nations generally control the waters and sea floor that extend 200 nautical miles from their shores. Beyond that, you hit the high seas, which aren’t subject to any individual nation’s laws or control. They span almost half the planet.

The high seas are home to species up and down the food chain, from phytoplankton to great white sharks. Much of the marine life that is also found closer to shore in national waters — including species of tuna and salmon, sea turtles and whales — also spends much of their lives in the high seas. That fact underlines the need for international collaboration on ways to protect species in need of help. Animals, after all, don’t recognize national boundaries.

There’s also deep sea life, including delightfully strange species such as anglerfish (which look like creepy characters in a marine haunted house), tripod fish (which appear to stand on bony fins like stilts) and hatchetfish (which have organs that light up in rows along their bellies).

It is sometimes said that we know more about the moon than the depths of the seas.

What’s at stake there?

“Our ocean has been under pressure for decades,” António Guterres, the United Nations secretary-general, said in a statement Wednesday as he encouraged delegates to reach a deal. “We can no longer ignore the ocean emergency.”

Overfishing and climate change are leading threats to marine biodiversity. Sharks and rays that live in the open ocean, for example, have declined by more than 70% since 1970, according to a global assessment.

New threats to marine life are emerging as people look to the ocean for the mining of valuable minerals and for possible ways to do “carbon sequestration,” which involve efforts to lock away carbon dioxide to keep it out of the atmosphere, where it is a major contributor to global warming.

Deep sea mining poses a risk to species that are particularly fragile and unknown, scientists say. Far from sunlight, these creatures grow and recover slowly.

The high seas have “probably the largest reserve of undiscovered biodiversity left on Earth,” said Lisa Speer, director of the international oceans program at the Natural Resources Defence Council. “Every time scientists go out there, they find species new to science.”

Human well-being is at stake, too, scientists say, because the health of the high seas is critical to the health of the overall ocean. Billions of people around the world rely on the ocean for food and jobs, according to the World Bank.

Oceans, which regulate climate across the planet, have blunted the effects of climate change on land by absorbing carbon dioxide and excess heat caused by burning fossil fuels. But that’s taking a toll on the oceans, making them hotter and more acidic, with less oxygen.

“The oceans are a vital part of what makes our Earth liveable, not just for marine biodiversity but for all life on Earth,” said Liz Karan, director of ocean governance at the Pew Charitable Trusts.

Aren’t there rules already in place?

A patchwork of international agreements and organizations regulate the high seas, but they focus on fishing, shipping, mining and fossil fuel extraction. While they are supposed to take biodiversity into account, doing so isn’t always in their interest, environmental advocates say. Even when they do, each body tends to pay attention to its own specific effects on marine life instead of considering the cumulative effects of all pressures.

 “The current structure of managing human activities on high seas is not a whole lot more rigorous than the Wild West,” Speer said. (The high seas are also notorious for abuses and lawlessness including human servitude and murder. This agreement wouldn’t address crimes like these.)

If ratified, the new treaty would create an international framework with a primary focus of protecting ocean species or ecosystems. It would be able to designate marine protected areas, places where fishing and other activities that harm marine life are restricted or prohibited.

That ability is critical if the world is to meet a historic goal set last December: To protect 30% of the planet’s land and oceans by 2030.

What were the sticking points?

A series of questions held up negotiations: What parts of the high seas can be considered for marine protected areas and how will they be decided? How will environmental reviews work when companies want to mine, drill or undertake another potentially harmful activity? What happens when the new treaty bumps into the authority of another existing body, like a fishery management organization?

And one of the most stubborn: Who will profit if valuable genetic resources — say, a cure for cancer — are discovered somewhere in the high seas? Developing nations said that they had a right to share in both scientific knowledge and in possible future profits. Wealthier nations countered that, if companies weren’t able to get sufficient return on investment, they might lack the incentive to invest in marine research.

Underneath lies a frustration from developing nations that has also roiled climate and global biodiversity talks: They feel as if they shouldn’t be penalized for problems that largely result from the activities of richer nations, not poorer ones.

 “African member states have not been the reason why we have the marine biodiversity crisis,” said Michael Imran Kanu, chief negotiator for a group of African countries and deputy permanent representative of Sierra Leone to the United Nations. “You’ve exploited it, you’ve benefited from these resources and now you are basically foreclosing the opportunity for others to go and exploit,” he added, referring to wealthier countries.

At the same time, he emphasized the need for a strong treaty, so that countries can’t find loopholes to continue overexploiting ocean resources.

What happened in the end?

Just before 9:30 p.m. Saturday, after negotiating for 36 hours, participants announced a deal. “The ship has reached the shore,” said the conference’s president, Rena Lee of Singapore. She choked back tears during a long standing ovation that followed.

While countries did not formally adopt the text, they agreed not to reopen negotiations on it. Marine protected areas would be determined by a vote, delegates decided, which is a win for biodiversity because the other possibility, consensus, could allow one country to block action.

A Greenpeace statement called the treaty “a monumental win for ocean protection” and an important one for multilateralism in a world that can feel ever more divided. Laura Meller, an oceans campaigner for Greenpeace who attended the talks, said, “Protecting nature and people can triumph over geopolitics.”

-New York Times