Talks in New York seek a treaty to safeguard the high seas, which support a huge range of biodiversity and provide oxygen that sustains life on Earth.

The high seas – areas lying beyond countries’ exclusive economic zones – make up nearly two-thirds of the world’s oceans. A global agreement is seen as crucial to preserve and manage these waters and their biodiversity.

“Humanity has been waging a senseless and self-defeating war on nature, and the ocean is on the front lines of the battle,” UN Secretary General Antonio Guterres said last month as he called on nations to conclude the delayed negotiations.

Here is what you need to know about the talks:

Why is ocean conservation important?

The world’s oceans play a major role in regulating the global climate. They provide oxygen that sustains human and animal life, drive weather systems and store about one-quarter of the planet-heating carbon dioxide generated by human activities.

“It makes this planet habitable,” said Liz Karan, who leads high seas protection work at the Pew Charitable Trusts. “They say that every second breath you breathe comes from the ocean.”

Oceans also support a huge range of biodiversity, including potentially millions of species that humans have not yet discovered.

According to the Red List of Threatened Species from the Swiss-based International Union for Conservation of Nature (IUCN), nearly 10 percent of underwater plants and animals assessed so far are threatened with extinction.

How are oceans being damaged?

The biggest driver of environmental decline in the oceans has been from indiscriminate fishing, said Jessica Battle, a senior expert on ocean policy and governance at the World Wide Fund for Nature.

It not only depletes fish stocks but also erodes the ability of their populations to rebuild, she said, and many fish are accidentally caught and later discarded as waste, so-called by-catch.

According to estimates, by-catch accounts for about 40 percent of the world’s global commercial catch.

Another significant threat to the oceans is pollution, including plastics, sewage and excess nutrients that wash from the land to create “dead zones” in the ocean by causing an overgrowth of bacteria on the sea floor that uses up oxygen and suffocates other life, Battle said.

At the same time, climate change is also degrading ocean health, causing coral reef bleaching and forcing fish to migrate to cooler waters.

What percent of oceans are protected?

During UN talks in December in Montreal, countries agreed on a landmark deal to slow and reverse biodiversity loss across the planet, including a target to protect 30 percent of the world’s lands and seas by 2030.

Conservationists hope the nature pact will provide momentum to reach an oceans treaty because the “30 by 30” goal will likely be unattainable without protecting the high seas.

Currently, 8 percent of the world’s marine areas are protected, which includes 1.4 percent of the high seas, according to the latest figures from the IUCN.

Areas of the high seas that are protected include parts of the North East Atlantic and Antarctic oceans, but because the protection accords are regional rather than global, they do not bind all governments, Battle said.

Are marine protected areas effective?

Marine protected areas (MPAs) help preserve nature by prohibiting certain activities such as fishing, and several scientific studies have shown well-enforced MPAs increase the number and diversity of species in the areas and beyond.

“If there is greater abundance of marine life within those areas of protection, they have spillover effects because MPAs don’t have closed borders,” Karan said.

However, she said their effectiveness hinges on having management plans in place to ensure enforcement, which includes using tools such as high-resolution satellites.

The treaty being negotiated in New York would fill a gap by creating a legal mechanism to establish protected areas in the high seas, Karan said.

“The real test will be creating those high seas protected areas and making sure that they are highly and fully protected from extractive activities,” she said.