There is something strange about being a diver and having an opinion on the deep ocean floor. I have never been there. Almost nobody alive has. The seabed four kilometres down is not a place anyone has dived, photographed in person, or spent meaningful time with. We know it from sediment cores, sonar maps, and the brief flickering returns of remotely operated vehicles. It is, by any honest measure, a place we do not yet understand. And we are about to start mining it.
The deep ocean floor is the largest and least explored ecosystem on Earth. We have better maps of the surface of Mars. The species that live in the abyssal plain, at depths of 4,000 metres and below, are mostly undescribed by science, and the ecological relationships between them are essentially unknown.
The International Seabed Authority, the UN-affiliated body that regulates the deep ocean floor in international waters, has been moving toward issuing the first commercial mining licences for several years. The targets are polymetallic nodules, potato-sized concretions of manganese, nickel, cobalt, and rare earth elements that lie scattered across the abyssal plain. They have been forming, slowly, for tens of millions of years. The companies positioning to extract them are arguing that the world needs the metals for the energy transition.
The argument is more contested than it sounds.
What Mining Actually Looks Like
The proposed extraction method is industrial in scale. A collector vehicle, roughly the size of a small house, would be deployed to the seafloor, where it would vacuum up the top layer of sediment along with the nodules embedded in it. The slurry would be pumped through a riser to a surface vessel, separated, and the residual sediment would be discharged back into the water column.
Each pass of the collector strips the seafloor down to the underlying clay. The nodules are gone. The microbial mat that grows on them is gone. The sessile organisms, sponges, corals, glass sponges that may be thousands of years old, are gone. Recovery, if it happens at all, takes geological timescales. Recolonisation studies of disturbed deep-sea sediment from forty years ago show essentially no return to baseline.
The discharged sediment is the second problem. It creates plumes that can travel for tens of kilometres in deep currents and settle on adjacent areas, smothering filter-feeders and altering the chemistry of the water column at depths where many species have spent their evolutionary history in conditions that change extremely slowly.
What We Don’t Know
The most honest answer to the question of what deep-sea mining will do is that nobody knows. The deep ocean floor was, until very recently, treated as essentially lifeless, a sediment desert with limited biological interest. Improved sampling technology over the last twenty years has shown the opposite. The abyssal plain hosts thousands of species per square kilometre, the majority of them new to science.
A 2023 study of the Clarion-Clipperton Zone, the Pacific seafloor area where the first mining is most likely to occur, identified more than 5,500 species in samples from a single research cruise. Most had no scientific name. The ecological function of these species, what they eat, what eats them, how they interact with the carbon cycle, remains almost entirely uncharacterised.
Mining a place we do not understand is not, in itself, an argument against mining it. But it is an argument for moving slowly, for requiring strong baseline science before extraction begins, and for accepting that any monitoring we put in place may not be capable of detecting the damage we cause until it is irreversible.
The Energy Transition Argument
The case for deep-sea mining is that the metals it would produce are needed for the batteries that will power the transition away from fossil fuels. This is true in a literal sense. Cobalt and nickel are required for current battery chemistries, and demand is growing.
It is less true as a strategic argument. Battery chemistry is changing fast. Sodium-ion and iron-phosphate batteries, both already commercial, use no cobalt and no nickel. Lithium iron phosphate batteries are now standard in most Chinese-manufactured electric vehicles and are increasingly common globally. Recycling of existing batteries is becoming economically viable at scale. The trajectory of battery demand for cobalt and nickel may already be flattening before deep-sea mining could begin commercial operations.
There is also a counter-argument from major automakers and battery manufacturers. BMW, Volvo, Google, and several others have signed pledges not to source materials from deep-sea mining. The reasoning is partly reputational and partly strategic. They do not want to be the companies whose supply chains were responsible for the destruction of the deep ocean.
What Is Happening at the ISA
The International Seabed Authority is currently negotiating the regulations that would govern commercial mining. As of 2026, those regulations are not finalised, but the pressure to issue licences is building. Several states and contractors have submitted formal applications for commercial extraction. Some are arguing that the absence of regulations should not delay extraction itself, a position that has been politically rejected so far but is being tested in earnest.
A growing number of states, including France, Germany, Spain, Chile, New Zealand, and several Pacific island nations, have called for a moratorium or precautionary pause on commercial mining until adequate scientific baselines and regulatory frameworks are in place. The position is not unanimous. Several states with sponsored mining contractors continue to push for early licensing.
The High Seas Treaty, which entered force in early 2026, creates a mechanism for designating marine protected areas in international waters, but how it interacts with mining licences remains unresolved. The next ISA assembly will be a critical moment. It is the kind of decision that gets made in technical sessions in Kingston and rarely makes the front pages of newspapers, and it will determine, more than almost any other single decision in the next decade, what the deep ocean looks like for the rest of human history.
Why It Matters to Divers
Recreational and technical diving never reaches the depths that would be affected by deep-sea mining. The abyssal plain is several kilometres below anywhere a human in scuba gear has ever been. Why should this matter to people whose interest in the ocean operates at recreational depths?
Two reasons. First, the deep ocean is connected to the shallow ocean by everything from carbon cycling to the migration of pelagic species. Damaging the deep ocean does not stay in the deep ocean. The reef fish we encounter on holiday and the sharks we travel to dive with are at the top of food chains that begin with processes that occur four kilometres below the surface.
Second, the diving community is one of the most consistent constituencies for ocean protection. The political pressure required to slow or stop deep-sea mining will not come from the abyssal plain itself. It will come from people who care about the ocean as a whole and have been paying attention for long enough to push back when the next thing comes along. This is the next thing.
