5 Surprising Stats Show Why High Seas Need Protection

Region covers two-thirds of the ocean and supports millions of species—including ours

Navigate to:

5 Surprising Stats Show Why High Seas Need Protection
Once thought devoid of life, scientists now estimate that the high seas could be home to millions of undiscovered species.
Sean Gladwell/Getty Images

On Dec. 24, 2017, the United Nations General Assembly took a momentous leap forward toward ensuring a healthy ocean by launching negotiations for a new international treaty to protect biodiversity on the high seas. These areas beyond national waters—often called the commons because they belong to everyone—are governed by a patchwork of sectoral organizations that regulate fishing, shipping, or mining but that lack the jurisdiction to make and implement comprehensive marine protections.

Adoption of the treaty would mark the culmination of more than a decade of talks at the U.N., and would ultimately create mechanisms to allow for the designation of marine protected areas, including some that are fully safeguarded, on the open ocean.

To celebrate World Oceans Day, here are five facts showing why the high seas are so special and worth protecting.

2 million: The number of unidentified species estimated to live in the ocean

The giant spiny lobster
The giant spiny lobster was discovered in 2005 in an area of high seas called Walters Shoals, off the southern tip of Madagascar.
Paul Kay/Getty Creative

It is often said that we know more about our solar system than we do about the depths of the ocean. With an average depth of more than 4 kilometers (2.5 miles), and a maximum depth of over 10 kilometers (6.2 miles), the high seas are difficult to explore, and it may be decades or longer before scientists know just how much life this region of the ocean supports. Some scientists estimate that there could be millions of undiscovered species beyond national jurisdiction.

95 percent of living space

Living space map
The light blue waters in this map represent all of the high seas. This vast ocean area performs many functions that, together, are vital to most life on Earth.

The high seas make up two-thirds of the world's ocean, and scientists estimate that these waters represent about 95 percent of the occupied habitat of Earth. The high seas also hold astonishing biodiversity, with organisms ranging from tiny plankton and bacteria to whales, sharks, tuna, and more—all of which need healthy waters to survive.

Every second breath is ocean

The high seas are critical to all life on Earth, in part by playing an important role in the processing of carbon dioxide.
Danilovi/Getty Images

Take a deep breath. Now take another. You can thank the ocean for one of those breaths, specifically microscopic organisms called phytoplankton, which, through photosynthesis, produce half the oxygen humans breathe. Much of the carbon dioxide needed for that process comes from other marine life, but a lot comes from the atmosphere. By absorbing and storing excess CO2, the high seas are helping to slow the impacts of climate change on land. Many people know that trees produce oxygen; it's time for wider recognition of how critical the ocean is to supporting life.

90 percent of world trade crosses our ocean

Without the high seas, international trade and commerce would be nearly impossible. Shipping routes are highly trafficked and critical to the world economy.
Patrick T. Fallon/Getty Images

A lot is happening on the high seas, particularly as humans continue to develop technologies that aid exploitation, travel, and commerce. Today, 90 percent of world trade is carried out through international shipping on the high seas, which involves enormous vessels crisscrossing the ocean. Collisions between ships and marine mammals, particularly whales, occur regularly and are a threat to the animals worldwide. And the potential effects of ocean noise on those mammals' communication is still being studied.

And 90 percent of global fish stocks are at risk

Huge numbers of fishing trawlers, like the ones shown here, traverse the high seas each day.

According to the U.N. Food and Agricultural Organization, 90 percent of global fish stocks are either depleted or fully exploited. Much of this fishing takes place on the high seas. Marine protected areas could help make fishing more sustainable by giving commercially valuable species the chance to feed, reproduce, and rebuild their populations in areas free from industrial or extractive activities.

Protecting the high seas is a big task, but by moving forward with a treaty, the countries of the world have shown a necessary commitment to safeguarding the ocean. When U.N. delegates gather in New York this September for the first round of treaty negotiations, it is essential they consider the value of the high seas to all life on Earth—from the tiniest, undiscovered organism to all of us who depend on the ocean for food, jobs, and the air we breathe.

Liz Karan directs Pew's work to protect ocean life on the high seas.

Whale shark
Whale shark

Governments Start Formal Talks on High Seas Treaty

Quick View

Governments Start Formal Talks on High Seas Treaty

After more than 10 years of debate and discussion, the United Nations is meeting this week to launch an intergovernmental conference to negotiate a treaty on global protections for critical marine biodiversity on the high seas. In late December, in a landmark moment for the oceans, U.N. member governments agreed by consensus to move forward with four negotiating sessions by mid-2020.

Many species of invertebreates, fish, and birds utilize the Sargasso Sea.
Many species of invertebreates, fish, and birds utilize the Sargasso Sea.
Issue Brief

Underwater Treasures of the High Seas

Quick View
Issue Brief

Once thought to be largely barren, the high seas are now known to be one of the planet’s largest reservoirs of biodiversity. Home to majestic whales, sharks, sea turtles, and other beloved and ecologically important species of marine life, the deep reaches of the high seas also support little-understood plants and animals as well as creatures not yet discovered.