The High Seas, as defined by the United Nations Convention on the Law of the Sea (UNCLOSE), includes the vast expanse of ocean and deep seabed beyond any one country's national jurisdiction (referred to as areas beyond national jurisdiction, or ABNJ) and covers about half of Earth's surface and two-thirds of the global ocean area.

View our map of the High Seas.

Protecting the High Seas is essential not only for individual species or ecosystems, but for maintaining the connectivity that allows the global ocean to function as one living system.

Despite its reputation as a broad, lifeless expanse equivalent to a desert at sea, the High Seas holds great biodiversity, helps mitigate climate change, and remains one of the least-protected areas on our blue planet.

Biodiversity

From underwater mountain ranges (seamounts) bustling with rare and unique forms of marine life, to vast seagrass beds and deep-sea coral reefs, the High Seas provides important habitat for many species, including migratory species such as sharks, tunas, sea turtles, seabirds, and whales that traverse ocean basins in search of food and mates. 

Climate

By absorbing heat and carbon dioxide, the ocean plays an outsized role in regulating our planet’s climate. Two-thirds of the ocean lies on the High Seas, and much of its deep waters—found beyond national borders—form a crucial part of this climate-regulating system. In the mesopelagic, or “Ocean Twilight Zone,” millions of animals migrate to the surface each night to feed before returning to the depths, bringing carbon back down with them. 

Learn more about our efforts to protect the Ocean Twilight Zone

30x30

In 2022, at the UN Convention on Biological Diversity’s 15th Conference of the Parties in Montreal, countries adopted the Kunming-Montreal Global Biodiversity Framework, which includes a target to protect 30% of the world’s lands and waters by 2030. Analysis shows that only around 3% of the ocean currently falls into fully or highly protected MPAs (MPAtlas).  With only five years left to reach the goal of protecting 30%, the establishment of MPAs under the BBNJ Agreement is one of the strongest pathways towards achieving this goal.

Track current progress towards 30x30 on our Marine Protection Atlas.

Threats

While the High Seas may seem out of reach (and therefore safe from the threats of human activity), they face many of the same—and several unique—threats compared to coastal ecosystems, including harmful fishing practices at an unsustainable scale, shipping, plastic and nutrient pollution, recent threats from deep sea mining and other geoengineering projects, and the multitude of negative impacts caused by climate change: warming waters, lower oxygen levels, and increasing acidity. Protecting the High Seas may seem out of touch with the everyday needs of humans, but it is increasingly vital to ensuring our collective future. 

Currently, only 1% of the High Seas is contained in MPAs, but that is about to change.

Explore current protections on the High Seas.

With the ratification and entry into force on of the agreement on the conservation and sustainable use of biodiversity beyond national jurisdiction (also called the BBNJ Agreement or “High Seas Treaty”), countries will now be able to propose MPAs on the High Seas.