Saving the world's oceans.

• Author: Frank, Mary Kate
• Position: INTERNATIONAL

More than half the planet is covered by water that belongs to all of us. Why is so little of it protected?

In the middle of the North Atlantic Ocean lies an area known as the Sargasso Sea. Thick clumps of seaweed float on its surface, providing shelter for baby sea turtles. This stretch of water also functions as a breeding ground for endangered eels, a feeding stop for migrating whales, and a home for hundreds of other species--some found nowhere else on the planet. Its ecosystem is so complex that the Sargasso Sea (see map, p. 14), is often called a "floating rainforest."

It's a critical habitat that scientists say is in need of protection. Its marine life is threatened by overfishing and plastic debris. And because the Sargasso is so far from any country's shores, no single nation has the legal authority to fully protect the area.

More than half of the world's ocean waters are in the same boat: They're too far from land to fall under the governance of any one country. Under international law, countries control only the waters within about 230 miles of their shores. The waters beyond that--known collectively as the high seas--belong to everyone.

The high seas cover about 80 million square miles and contain some of the most important and threatened ecosystems in the world. Only about 1 percent of those waters are protected-and very few rules exist about what can and can't be done there.

However, a new United Nations (U.N.) treaty could change that. Conservationists hope the pact will allow for the creation of new protected areas on the high seas and require those who want to engage in commercial activities there, such as fishing or drilling, to assess any possible environmental impact.

Those measures would be a step toward helping the oceans recover from damage that has already been done. Habitat destruction, overfishing, pollution, and climate change are "pushing the ocean system to the point of collapse," according to a 2014 report by the Global Ocean Commission.

"People assume that the ocean is going to go on and on, but it's really in very desperate shape due to human activities," says Peggy Kalas of the High Seas Alliance, a partnership of more than 30 environmental groups. "If this treaty goes forward, it will be a game changer for the ocean and the way that it's regulated down the road."

Humans couldn't live on Earth without the ocean. It produces much of our food and more than half of the planet's oxygen. It regulates the climate, both by trapping the sun's heat and by absorbing some of the carbon dioxide we release into the atmosphere. The ocean gives us energy in the form of wave, wind, and tidal power. It's also critical to our economy: More than 90 percent of the world's trade--products ranging from TVs to jeans--travels by sea.

The high seas play an essential role in all those areas. But one of the most important things the waters offer, scientists say, is their wealth of biodiversity.

Early explorers thought the open ocean was barren, but it's actually full of life. Sharks, whales, sea turtles, and seabirds are just a few of the animals found in these waters. Beneath the waves lie deep-water coral reefs, vast mountain ranges, and creatures that haven't yet been discovered. With nearly every deep-sea voyage, scientists find new species. And there's still plenty to uncover: As much as 95 percent of the ocean remains unexplored.

The Law of the Sea

The main international agreement regarding the ocean was negotiated in the 1970s, before much deep-sea exploration had occurred. That treaty set rules for everything from shipping to navigation. Perhaps most important, it established that each country has the sole right to the natural resources within roughly 230 miles of its shores. The treaty didn't go into detail, however, about the natural resources that lie beyond those areas.

So who oversees the high seas? The answer is a host of groups, each of which handles only a very specific issue. The International Maritime Organization, for example, regulates shipping. The International Seabed Authority is in charge of deep-sea mining. And various regional organizations manage fishing. There's little coordination between the different agencies, making it difficult to safeguard the high seas.

Marine scientist Lisa Speer is director of the Natural Resources Defense Council's International Oceans Program. She likens the open ocean to the Wild West. "There are few rules and no sheriff," says Speer. "It's basically a free-for-all."

One example: Commercial fishermen are taking too many...