Policy

Protecting the High Seas

Continue
Humpback whales swimming underwater.

The future of our ocean will be shaped on the high seas.

Marine Life Humpback whales swimming in the deep blue sea in Moorea, French Polynesia. © Yuka Takahashi/TNC Photo Contest 2023

International waters, known as the high seas, span more than 60% of the world’s ocean and are home to diverse ecosystems, deep-sea habitats, and migratory corridors for iconic species. The riches of these waters also support economies and communities worldwide. As part of the global ocean system, the high seas support the ocean’s role in stabilizing the climate. Overall, the ocean absorbs roughly 30% of human‑generated CO₂ emissions and more than 90% of excess heat.

What is blue carbon? The ocean and climate change (2:11) We can all do our part to protect our ocean and its coasts. Because when mangroves, marshes and seagrass join forces with clean energy, forests and other habitats—that’s how we turn the tide on climate change.

Despite their importance, less than 1.5% of the high seas are currently protected.

With the ratification of the High Seas Treaty, countries now have a pathway to establish connected, representative, and global Marine Protected Areas (MPAs) in international waters. This new governance framework can help protect marine biodiversity, strengthen ecosystem resilience, and support the more than 3 billion people whose lives and livelihoods depend on a healthy ocean. 

School of fish in the Raja Ampat Islands of Indonesia.
Supporting Marine Conservation The high seas are home to diverse marine ecosystems, deep sea habitats, and migratory corridors. © Awaludinnoer YKAN
A mother humpback whale swimming with its calf.
Marine Mammals A humback whale and calf in Vava'u, Kingdom of Tonga. © Justin Bruhn /TNC Photo Contest 2018

TNC is working closely with governments and partners to help establish the first generation of high seas MPAs by 2030.

Leveraging science-driven design, strong regional and global partnerships, innovative financing, and policy leadership, TNC is currently focused on three crucial high-seas areas: the Walvis Ridge, the Salas y Gómez and Nazca Ridges, and Micronesia. In the future, we aim to expand our work to further sites. Collectively, this work has the opportunity to contribute up to 200 million hectares of ocean protection, an area larger than Indonesia. 

The Path Forward

The scale and complexity of protecting the high seas demands collaboration across sectors, geographies, and institutions. Working together allows us to align efforts, share knowledge, and mobilize the resources needed to address high-priority opportunities in key regions.

As a member of the High Seas Alliance, TNC is driving international policy engagement at the United Nations, coordinating with partners already in place for specific MPAs, and ensuring that our efforts are complementary and grounded in local and regional realities. We are also working to support finance, monitoring, data sharing, and capacity-building efforts—critical components for ensuring the High Seas Treaty delivers on its promise of long-term ocean stewardship.