The high seas, Earth’s last wild frontier at risk

By Giovanni Prete

New York (Earth.org) -- The high seas–the vast waters beyond national jurisdiction – cover nearly two-thirds of our planet. They are home to some of Earth’s most mysterious and vital ecosystems, from migratory whales to deep-sea corals, and serve as a crucial regulator of the global climate by absorbing carbon and heat.

Yet despite their importance, they remain largely unprotected, vulnerable to overfishing, deep-sea mining, plastic pollution, and the mounting impacts of climate change. 

Unlike coastal waters, which fall under national control, the high seas encompass all areas of ocean beyond the 200 nautical mile exclusive economic zones of any country. 

These remote waters play a key role in maintaining planetary health. They support biodiversity hotspots, provide critical fisheries for millions of people, and store carbon that would otherwise accelerate climate change. In short, the high seas are a lifeline for both marine ecosystems and human societies.

The high seas are often described as the “blue heart” of our planet. They are a major driver of Earth’s life-support system. These waters are also home to unique ecosystems like hydrothermal vents – where life exists without sunlight – and massive migratory routes for whales, tuna, sharks and seabirds. 

Fisheries from the high seas also provide a significant portion of the world’s seafood, feeding billions of people and sustaining global economies. A 2018 study published in Science Advances revealed that nearly half of the high seas fishing would be economically unprofitable without heavy government subsidies, highlighting how closely tied these industries are to policy and governance. 

Yet it isn’t just about fish. Scientists have discovered microbes in the high seas with properties that could unlock breakthroughs in medicine, including potential treatments for cancer and antibiotic resistance. The high seas are a reservoir of undiscovered genetic resources, a frontier of science that humanity is only beginning to explore. 

For decades, the high seas were thought to be too vast and remote to be threatened by human activity. That myth has been shattered as we now know that these waters face one of the most urgent ecological crises on the planet. 

Overfishing remains the most immediate threat. Industrial fleets from wealthier nations dominate high sea fishing, often targeting species like tuna, squid, and deep-sea fish that take decades to mature. This not only depletes populations but also devastates ecosystems by disrupting predator-prey balances. 

Deep-sea mining poses an emerging danger. Companies and governments are eyeing the seafloor for polymetallic nodules rich in cobalt, nickel, and rare earth elements used in renewable energy technologies. However, scientists warn that mining could cause irreversible damage to fragile ecosystems that take millennia to form.

The Deep Sea Mining Moratorium campaign, supported by scientists and states alike underscores how little we know about these ecosystems before we destroy them. Most recently, at the third United Nations Ocean Conference in Nice, France, world leaders once again called for a deep-sea mining moratorium, further highlighting how deep-sea mining could potentially destroy the high seas. 

Moreover, plastic pollution is rampant in the high seas. Ocean currents converge into massive gyres, forming garbage patches where plastics accumulate, break down into microplastics, and enter food chains. Researchers have found plastic fibers in deep-sea trenches and even inside marine animals in the remotest corners of the ocean. 

Climate change further compounds these threats. The high seas are warming, becoming more acidic, and losing oxygen. These changes threaten coral reefs, plankton populations, and migratory species that rely on specific temperature and oxygen conditions. 

One of the greatest challenges in protecting the high seas is governance. Because these waters lie outside national boundaries, no single country has jurisdiction over them. Instead, they are governed by a patchwork of international agreements, the most significant of which is UNCLOS, adopted in 1982. 

While UNCLOS lays the legal foundation for ocean governance, it has limitations. It primarily regulates navigation, territorial claims, and seabed mining through the International Seabed Authority. However, it offers little in the way of comprehensive biodiversity conservation. Fisheries are managed by Regional Fisheries Management Organizations, but enforcement is weak and varies across regions. 

This government vacuum has allowed powerful nations and industries to exploit high seas resources with little accountability. The principle of the “freedom of the seas” has too often translated into a free-for-all where short-term profits outweigh long-term sustainability. 

In March 2023, after nearly two decades of negotiations, the UN adopted the High Seas Treaty, also known as the Biodiversity Beyond National Jurisdiction Agreement. 

The treaty has the potential to transform high seas governance by establishing mechanisms to create Marine Protected Areas on the high seas, regulate environmental impact assessments, and equitably share marine genetic resources. 

If fully ratified and implemented, the treaty could help meet the global 30×30 target  – protecting 30% of the ocean by 2030 – as agreed upon at the UN Biodiversity Conference in 2022. But challenges remain. At the last UN Ocean Conference in June, 18 countries ratified the agreement, bringing the total to 50. Ratification by at least 60 countries is required before the treaty can enter into force, and questions linger about financing, enforcement, and political will. 

Still, the treaty marks a historic moment: for the first time, the global community has recognised that the high seas must be managed as a shared responsibility, not as an open-access resource.

The fate of the high seas hangs in the balance. On the one hand, scientific understanding and international cooperation are advancing. On the other hand, industrial exploitation and climate change are accelerating faster than protections can be put in place.

Without strong action, the high seas could become a tragedy of the commons, stripped of biodiversity and resilience. Yet with proper governance, they could remain one of the last great wild frontiers, sustaining both humanity and the planet for generations to come. 

The high seas remind us of a profound truth: the ocean does not belong to one nation. It belongs to all of us – and we are responsible for its future.

Giovanni Prete is a communicator, writer, creator, actor and environmental advocate.

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