Amanda van Dyke is a mining and critical minerals expert with more than 25 years of experience spanning mining, finance, commodities, energy transition materials and industrial strategy. She has worked across investment management, private equity, mining finance, capital markets and strategic advisory roles, with a particular focus on critical minerals, energy systems and the growing intersection between resources, geopolitics and industrial policy.

Amanda is the founder of the Critical Minerals Hub, an independent public-interest platform dedicated to improving understanding of the minerals, materials and supply chains that underpin modern civilisation, energy systems, advanced technology and economic development. She is also the author of The Mineral Imperative, a book examining the foundational role of minerals and energy in the global economy, technological progress and the energy transition. Her work focuses on the concept of the “mineral imperative” — the idea that every modern economy, energy system and technological advance ultimately depends on secure access to mined materials and industrial supply chains.

Introduction

The 21st century economy is being rebuilt on minerals. Every electric vehicle, battery, transmission line, data centre, wind turbine, advanced semiconductor and weapons system ultimately depends on enormous quantities of copper, nickel, cobalt, manganese, lithium and rare earth elements. The modern world is entering what can only be described as a new age of material intensity.

In the last 25 years alone, the total tonnage of materials humanity extracts from the Earth has more than doubled. Yet most forecasts suggest we need to at minimum double it again just to continue the present trajectory over the next 25 years. According to the World Bank supporting global electrification, AI infrastructure, industrial growth and rising living standards as well delivering energy-transition scenarios implies.

This is where the problem begins.

Good ore bodies are becoming harder to find. Ore grades are declining across every major ore type. New mines increasingly require larger pits, more waste rock, bigger tailings dams, more water, more energy and more capital to produce the same tonne of metal. The mining industry is increasingly experiencing diseconomies of scale: where each additional tonne of material becomes more expensive and environmentally intensive, not less.

At the same time, many of the world’s remaining large terrestrial deposits sit beneath tropical forests, near densely populated regions, or inside geopolitically difficult jurisdictions. Nickel expansion is pushing further into Indonesian rainforest systems. Copper projects face water stress and social conflict across Latin America. Cobalt remains heavily concentrated in the Democratic Republic of Congo. Rare earth supply chains remain dominated by China.

Against that backdrop, attention has increasingly turned toward a mining frontier that, until recently, belonged more to science fiction: the deep ocean.

Thousands of metres below the surface, vast areas of the seabed contain polymetallic nodules, cobalt-rich crusts and rare-earth-rich muds holding many of the exact metals modern industrial systems are struggling to secure. In some cases, the quantities involved rival or exceed known terrestrial reserves.

This immediately creates a difficult but unavoidable question.

If the choice is not between mining and no mining, but between different forms of mining in different environments, should the deep ocean automatically be excluded? Or should it be assessed using the same comparative standards we apply everywhere else: total environmental footprint, carbon intensity, waste generation, biodiversity impact, geopolitical concentration and human cost?

What is Deep-Sea Mining?

Deep-sea mining is often discussed as though it were a single activity. In reality it refers to several very different types of mineral extraction taking place across radically different ocean environments and depths.

The first, and by far the most commercially important today, involves polymetallic nodules scattered across abyssal plains at depths of roughly 4,000–6,000 metres. These nodules are essentially loose rocks lying exposed on the seabed, rich in manganese, nickel, cobalt and copper. The largest known concentration sits within the Clarion–Clipperton Zone (CCZ), a massive region between Hawaii and Mexico covering roughly 4.5–6 million square kilometres.

Importantly, these nodules do not need to be blasted, drilled or excavated from hard rock. They are already sitting on the sediment surface. They are essentially placer deposits; most proposed mining systems therefore resemble highly engineered sieving or dredging operations rather than conventional underground or open-pit mining. Large robotic collector vehicles would move slowly across the seabed, gathering nodules and a thin layer of sediment before pumping the material to a surface vessel through vertical riser pipes. Some emerging technologies involve autonomous robotic submarine systems selectively collecting nodules and returning them to the surface.

The second type of deep-sea mining targets seafloor massive sulphides around hydrothermal vent systems, typically between 1,500 and 3,000 metres depth. These are much more analogous to traditional hard-rock mining. Metal-rich sulphide deposits containing copper, zinc, gold and silver form around ancient volcanic systems, and extracting them would require mechanical cutting and fragmentation of the seabed itself. Because hydrothermal vents can host highly specialised ecosystems, this category is generally considered environmentally more invasive and controversial. Nautilus minerals attempted this type of mining in the Papua New Guinea EEZ but went into administration in 2019 before it started mining. 

The third category involves cobalt-rich ferromanganese crusts coating underwater mountains known as seamounts, usually between 800 and 3,000 metres depth. These crusts accumulate over millions of years as thin mineral layers cemented directly onto rock surfaces. Mining them would likely require grinding or cutting the crust away from the underlying basalt, effectively strip-mining parts of submarine mountains.

There is also a fourth emerging category attracting growing attention: rare-earth-rich muds. Japan has identified large rare-earth deposits within its own Exclusive Economic Zone around Minamitorishima Island. These Japanese mud deposits sit at depths similar to abyssal nodule fields and may potentially be recovered by collecting a few meters of shallow sediment layers rather than cutting solid rock. Like nodules, they represent a form of mineral harvesting at the sediment-water interface rather than conventional excavation.

This distinction matters because much of the public imagination still pictures deep-sea mining as underwater open-pit mining. The reality, at least for the dominant commercial focus today, is quite different. The leading projects under development are primarily targeting loose mineral deposits resting on some of the flattest, darkest and least biologically productive regions of the ocean floor. 

From Scientific Curiosity to a New Mineral Frontier

Deep-sea mining did not suddenly appear as a futuristic idea dreamt up for the energy transition. The industry has been developing, quietly and intermittently, for more than half a century.

The story began in the 1870s, when the HMS Challenger expedition first dredged strange black nodules from the Pacific seabed. But it was during the Cold War era, particularly through the 1960s and 1970s, that governments and industrial consortia realised these “rocks” contained enormous concentrations of nickel, cobalt, copper and manganese. Attention rapidly focused on the Clarion–Clipperton Zone (CCZ), a vast abyssal plain between Hawaii and Mexico covering roughly 4.5–6 million square kilometres, around 1–1.5% of the entire global ocean floor.

What followed was effectively the first deep-sea mining boom. American, Japanese, German, French, Soviet and multinational consortia spent hundreds of millions of dollars developing prototype collection systems, metallurgical processing flowsheets and seabed mapping technologies. By the late 1970s, engineers were already recovering nodules from depths of 4,000–6,000 metres and testing vertical lifting systems capable of pumping ore slurry to surface vessels.

Then the industry stalled. Metal prices weakened, the Cold War ended, financing dried up, and perhaps most importantly, nobody could agree who owned the seabed. That legal vacuum ultimately led to the creation of the International Seabed Authority (ISA) under the UN Convention on the Law of the Sea.

Under UNCLOS, coastal states control what is known as an Exclusive Economic Zone, or EEZ, extending roughly 200 nautical miles from their coastline. Within that zone, countries have sovereign rights over seabed resources, fisheries and energy development. Beyond that boundary lies “the Area”: international waters and seabed governed collectively through the ISA as the so-called “common heritage of humankind.”

That distinction matters enormously. Japanese rare-earth mud projects near Minamitorishima, for example, sit within Japan’s EEZ and are therefore controlled directly by Japan. The Cook Islands, Norway and others are developing similar domestic frameworks within their own waters. The CCZ, by contrast, sits largely in international waters and therefore falls under ISA jurisdiction.

Today the ISA has issued roughly 30 exploration contracts, including around 19 for polymetallic nodules, most of them concentrated in the CCZ. China holds the single largest position through multiple state-backed entities, alongside licences sponsored by countries including Russia, India, Japan, Korea, France, Belgium, Germany, the UK and several Pacific Island states. Many of these licences are not new. Some trace their origins back nearly 30 years to the earliest ISA exploration regimes in the 1990s, meaning contractors have already spent decades collecting geological, environmental and engineering data across enormous parts of the Pacific seabed.

And while public discussion often implies the industry remains hypothetical, the reality is that large parts of the sector have already moved well beyond basic exploration. Companies such as The Metals Company (via NORI) and Belgium’s GSR have completed integrated pilot mining tests recovering thousands of tonnes of nodules from the seafloor and monitoring sediment plumes and equipment performance in real-world conditions. China, meanwhile, has been aggressively expanding both exploration and technology development globally, including testing collector systems, submersibles and seabed engineering technologies across multiple regions. Unlike Western-listed companies operating under public disclosure regimes, however, Chinese state-backed programmes release relatively little detailed operational data, making the true extent of their progress difficult to assess externally.

What is clear is that deep-sea mining is no longer theoretical technology. The engineering challenge has largely shifted from “can it work?” to “under what political and regulatory conditions will it be allowed to operate?”

The Regulatory Environment and Global Divisions 

That question has now triggered one of the most politically divisive resource debates of the modern era.

The International Seabed Authority was created under UNCLOS in 1994 to regulate mineral related activities in international waters. It was originally intended to create a workable international framework allowing seabed minerals to be developed while protecting the marine environment and distributing economic benefits globally. Instead, after more than three decades, the organisation remains locked in prolonged negotiations over a Mining Code that still does not fully exist, despite the fact that it has granted over 30 deep sea mining exploration licences, all of whom are seeking conversion to mining licences.

As of 2025–2026, no commercial exploitation licence has been granted in international waters despite billions of dollars having already been spent on exploration, environmental baseline studies, vessel systems, robotics and metallurgical testing. Contractors and sponsoring states increasingly argue that the UN system has failed to convert decades of scientific and financial investment into a functioning regulatory pathway.

Into that vacuum stepped a growing NGO-led campaign calling for a moratorium, precautionary pause, or outright ban on deep-sea mining. Several European countries, along with some Pacific and Latin American states, have aligned themselves with this position, arguing that ecological understanding of abyssal ecosystems remains incomplete and commercial mining should not proceed without stronger safeguards.

But the global picture is far more divided than the mainstream public narrative suggests.

China, India, Japan, Korea and Russia continue to actively support commercial development. Small island developing states such as Nauru, Tonga and Kiribati view deep-sea mining not as an abstract environmental debate, but as a potentially transformational economic opportunity capable of generating royalties, infrastructure investment and strategic leverage in a resource-constrained world. Many of these nations sponsored ISA contractors in good faith, spent millions supporting exploration programmes, and now argue that the UN system is effectively paralysed by political and environmental activism leading to endless procedural delay.

The United States has increasingly moved in the same direction, it never ratified UNCLOS, therefore it is not strictly bound by the treaty. Washington has begun revitalising its domestic deep-sea mining framework under the National Oceanic and Atmospheric Association (NOAA) and through the Deep Seabed Hard Mineral Resources Act (DSHMA), partly driven by concern that the West risks falling behind China in yet more critical mineral supply chains.

That geopolitical fracture became unmistakable when The Metals Company announced plans to pursue a US NOAA permitting pathway rather than continue relying exclusively on the ISA process. In effect, one of the world’s most advanced deep-sea mining companies concluded that the UN-centred system had become too politically stalled and NGO-dominated to provide a credible route to commercial production.

This is now the core reality of deep-sea mining. The resources are known. The technologies largely exist. The exploration and environmental baseline data has been accumulated over decades. The real battle is no longer geological or even engineering.

It is geopolitical.

And beneath the moral language surrounding the debate sits a much harder strategic question: if the world requires dramatically more nickel, copper, cobalt and manganese for electrification, AI infrastructure, defence systems and industrial growth, who will control the next frontier of mineral supply — and under whose rules?

Why the Deep-Sea Matters: The Scale of the Resource

The reason deep-sea mining has become such a geopolitical flashpoint is simple: the scale of the resource base is enormous.

Not “interesting.” Not “incremental.” Potentially civilisation-scale.

Polymetallic nodules scattered across abyssal plains contain many of the exact metals modern industrial systems are struggling to secure nickel, cobalt, copper and manganese. These are the core inputs into batteries, electrical systems, defence technologies, AI infrastructure, transmission networks and industrial alloys. And unlike many terrestrial deposits, the metals already occur together in a single ore body sitting exposed on the seabed, rather than buried beneath forests, villages or hundreds of metres of rock.

Globally, scientists estimate total polymetallic nodule resources may exceed 1 trillion tonnes. The Clarion–Clipperton Zone alone is thought to contain roughly 20 billion tonnes of nodules spread across the seabed between Hawaii and Mexico.

The numbers inside those nodules are staggering.

Estimates for the CCZ alone commonly include:

• More than 5–6 billion tonnes of manganese
• Around 250–350 million tonnes of nickel
• Roughly 200–300 million tonnes of copper
• More than 40–70 million tonnes of cobalt

To understand why that matters, global annual nickel production today is roughly 3.5 million tonnes per year. Global cobalt production is only around 230,000 tonnes annually. The contained cobalt in the CCZ may therefore represent centuries of current global production.

In some assessments, the cobalt contained in CCZ nodules alone exceeds all known economically recoverable terrestrial cobalt reserves combined several times over.

Rare earths tell a similar story.

Within Japan’s EEZ around Minamitorishima Island, researchers have identified large accumulations of rare-earth-rich muds containing potentially tens of millions of tonnes of rare earth oxides. Importantly, these include both light and heavy rare earths, the latter being among the most strategically important and hardest to secure materials in the global economy.

In other words, countries are not exploring the deep sea because it is scientifically interesting. They are exploring it because the opportunity and necessity have become impossible to ignore.

None of this means these deposits are automatically economic. Resources are not reserves. A deposit still must be technically recoverable, environmentally permitted and commercially viable. Deep-sea mining remains expensive, politically contested and technologically challenging. But from the perspective of the mineral imperative, the logic is increasingly obvious.

The Ocean Environment

The ocean is often spoken about as if it were a single, uniform environment: a vast blue wilderness stretching from coastline to horizon. In reality, it is more like an entire vertical planet layered on top of itself, with radically different ecosystems stacked through nearly 11 kilometres of depth. The difference between the sunlit surface waters and the abyssal plains targeted for deep-sea mining is not merely one of distance, but between biological abundance and near-biological scarcity; between ecosystems fuelled directly by sunlight and some of the most energy-starved environments on Earth.

The uppermost layer of the ocean, the epipelagic or “sunlit” zone, extends from the surface to roughly 200 metres depth. This thin surface layer supports almost all marine primary productivity. Sunlight enables phytoplankton to photosynthesise, forming the foundation of the marine food web and supporting fisheries, coral reefs, whales, dolphins, sharks, and the immense migratory systems that underpin global marine ecosystems and food supplies. Marine phytoplankton are estimated to produce roughly half of global oxygen production and fix tens of billions of tonnes of carbon annually through photosynthesis. Human interaction with the ocean is also overwhelmingly concentrated here: shipping, fishing, tourism, offshore energy, plastic pollution, nutrient runoff, and warming impacts disproportionately affect this relatively shallow layer.

Below this lies the mesopelagic or “twilight” zone, between roughly 200 and 1,000 metres depth, where sunlight rapidly fades and photosynthesis ceases. Yet life remains surprisingly abundant. Vast populations of lanternfish, bristlemouths, squid, jellyfish, and vertically migrating zooplankton occupy this realm, many rising toward the surface at night before descending again during daylight hours. Scientists increasingly believe it is the largest fish habitat on Earth.

Deeper still lies the bathypelagic or “midnight” zone, from around 1,000 to 4,000 metres depth. Here sunlight disappears entirely. Temperatures hover only a few degrees above freezing, pressures climb to hundreds of atmospheres, and food becomes extraordinarily scarce. Life persists, but in sparse and highly specialised forms adapted to crushing pressure, darkness, and chronic energy limitation. Most organisms survive on “marine snow”, the slow rain of organic particles drifting down from surface waters above. In effect, the deep ocean survives on leftovers. Whales and other megafauna live above the zone, and while they can dive to a maximum of 3000, briefly, they rarely do. 

And then we reach the abyss.

The abyssopelagic zone and abyssal plains, generally between 4,000 and 6,000 metres depth, are among the least biologically productive environments on Earth. These immense flat sedimentary plains cover more than half of the planet’s surface area and host many of the world’s polymetallic nodule deposits, including those in the Clarion–Clipperton Zone. Conditions here are extraordinarily stable: near-freezing temperatures, complete darkness, immense hydrostatic pressure, and vanishingly low food availability. At 5,000 metres depth, pressures exceed 500 atmospheres, equivalent to roughly 50 jumbo jets pressing on every square metre.

The result is an ecosystem defined less by abundance than by persistence. Biomass on abyssal plains is extraordinarily sparse, often hundreds to thousands of times lower than in terrestrial ecosystems. Much of the living carbon is microbial. Worms, tiny invertebrates, sea cucumbers, brittle stars, and microbial mats dominate these environments, punctuated occasionally by isolated seamounts or hydrothermal systems that act as localised oases of higher productivity.

This ecological context matters enormously because much of the public discussion around deep-sea mining implicitly treats all marine ecosystems as ecologically equivalent. They are not.

Comparing the Abyssal Mining to Terrestrial and Coastal Mining

The contrast between abyssal plains and terrestrial mining regions is profound. Roughly 80–90% of global biomass is terrestrial, overwhelmingly concentrated in forests, grasslands, soils, and land plants. Tropical rainforest systems such as the Congo Basin or the forests of Indonesia contain immense standing biomass and some of the highest biodiversity densities on Earth. A single hectare of tropical rainforest may contain hundreds of tonnes of living plant matter alongside thousands of insect, fungal, microbial, bird, amphibian, and mammal species interacting through highly complex food webs. Even relatively sparse terrestrial systems, such as the Arabian–Nubian Shield or the Atacama Desert, support orders of magnitude more biomass per square metre than abyssal sediments. 

Mining in these regions often requires large-scale deforestation, road construction, water diversion, tailings storage, waste-rock stripping, and long-term ecological disturbance in biologically dense or socially sensitive environments.

Coastal mining already targets a wide suite of materials: sand and gravel for cement and concrete, land reclamation, glassgrade silica sand is mined in the tens of millions of tonnes per year,  heavy mineral sands for titanium and zircon. These same shorelines also host dense human settlement, ports, tourism, aquaculture and small‑scale fisheries, concentrating more overlapping pressures into a narrow coastal band than almost anywhere else on Earth. Biomass in these shallow systems typically reaches hundreds to thousands of grams of carbon per square metre, yet we have normalised large‑scale dredging, suction and trawling in precisely these zones—technologies that strip or fluidise sediments and erode shorelines in ecosystems that are conservatively 500–3,000 times more complex and biomass‑dense than the abyssal plains.

Recent work in the Clarion–Clipperton Zone suggests species diversity may still be surprisingly high in absolute terms.  But this can create a misleading public impression. Diversity is not the same thing as ecological density, complexity or biomass. Biomass estimates for the CCZ abyssal seafloor are typically on the order of only 1–10 grams of carbon per square metre in animals, rising perhaps to a few tens of grams when microbial biomass is included. By comparison, Indonesian tropical rainforests may contain roughly 15–40 kilograms of above-ground biomass per square metre, while even semi-arid systems such as the Arabian–Nubian Shield commonly support around 0.5–2 kilograms per square metre. In practical terms, tropical rainforest systems where we currently mine nickel, cobalt, and copper contain roughly 1,000–10,000 times more biomass per unit area than the CCZ abyssal plain, while even desert-like terrestrial mining regions support approximately 100–1,000 times more.

Abyssal plains are not lifeless. But neither are they ecologically equivalent to tropical rainforests, coastal shallows, or productive upper-ocean fisheries. We are, in effect, comparing intensely productive ecosystems supporting enormous concentrations of life against vast dark sedimentary plains with 300 to 10,000 times less biomass than typical terrestrial or upper-ocean environments. That does not automatically justify deep-sea mining. But it fundamentally changes the framing of the debate.

The Core Objections to Deep-Sea Mining, and the Rational Responses

Deep-sea mining attracts a relatively small number of core objections that are often presented as absolute vetoes rather than trade-offs to be weighed against the impacts of terrestrial mining already underpinning the modern economy. Below is a concise summary of the principal concerns and the broader context in which they should be understood.

Irreversible biodiversity loss and habitat destruction

The primary objection is that polymetallic nodules form the foundation of unique abyssal ecosystems: hard “islands” in soft sediment plains that host sponges, microbes, and specialised invertebrates that evolved over millions of years. Because nodules grow so slowly, critics argue that removing them permanently destroys habitats that cannot recover on human timescales.

This is broadly true. Nodule removal is effectively irreversible over human timescales, and abyssal ecosystems are real ecosystems. But context matters. All mined minerals irreversibly remove geological artifacts that cannot be replaced over human timescales.By any objective measure of biomass and ecological productivity, abyssal plains sit near the bottom of Earth’s biome hierarchy. Humanity already mines roughly 1–2% of the terrestrial surface while driving far larger biodiversity losses across high-biomass ecosystems through agriculture, infrastructure, deforestation, and urban expansion. Even large-scale abyssal mining would disturb only a small fraction of an environment covering more than half of Earth’s surface. The relevant question is therefore not whether impacts exist, but whether shifting some mining from biologically rich terrestrial systems to ultra-low-biomass abyssal plains reduces overall environmental harm per tonne of metal produced.

Sediment plumes and water-column impacts

Another major concern is sediment plumes. Mining collectors will disturb seabed sediments, while processing systems may discharge fine particles back into the water column. Critics fear these plumes could smother abyssal organisms and spread across large areas for years or decades.

Sediment plumes are real and will require strict monitoring and management. But again, scale and context matter. Abyssal plains are among the least dynamic and least populated environments on Earth: weak currents, no plants, almost no fish, and communities dominated by microbes and tiny infauna. A slowly dispersing plume in such an environment is fundamentally different from sediment pollution in a river mouth, coral reef, mangrove, or fish nursery.

Society already tolerates vastly larger sediment and pollution plumes from terrestrial mining, agriculture, dredging, shipping, urban runoff, and coastal industry in far richer ecosystems. The rational question is not whether any plume occurs, but whether those impacts justify an outright ban.

Noise, light, and carbon-cycle disruption

Mining systems will also introduce industrial noise and artificial light into deep ocean environments that are naturally dark and relatively quiet. Some researchers worry this could affect deep-sea organisms adapted to darkness and low-noise conditions. Others argue disturbing abyssal sediments could disrupt carbon storage or release CO₂.

These concerns deserve careful study, but they are overstated. The upper ocean and continental shelves are already saturated with shipping noise, seismic surveys, offshore energy infrastructure, deep sea cables and military activity in ecosystems containing vastly higher biomass densities than the CCZ. Deep-sea mining would introduce additional noise into quieter waters, but in environments hosting comparatively little life per unit area.

The carbon argument is even weaker. Organic carbon concentrations in CCZ sediments are extremely low, and current modelling suggests any carbon released through mining disturbance would be negligible compared with global anthropogenic emissions or land-use change or even land based mining. From a climate perspective, the more important question is whether the metals produced enable lower-carbon energy and industrial systems elsewhere.

Scientific uncertainty and governance gaps

Opponents also argue that the deep sea remains too poorly understood for commercial mining to proceed responsibly. Much of the ocean floor remains poorly mapped, many abyssal species are undescribed, and long-term ecosystem responses remain uncertain. Critics further argue that the International Seabed Authority suffers from governance conflicts because it is tasked both with regulating mining and enabling seabed resource development.

There is genuine uncertainty around deep-sea ecosystems. But uncertainty is not unique to the abyss. Many terrestrial mining frontiers in tropical forests, Arctic systems, and mountain watersheds proceed with weaker baseline data and less environmental monitoring than what is currently being assembled for the CCZ.

In reality, the CCZ is now one of the most intensively studied deep-sea regions on Earth, with decades of biological, geological, geochemical, and plume research already completed. The fact that many species remain undescribed is also not unique. Globally, scientists have formally described roughly 2–2.5 million species, but most estimates for the true total range from around 8–15 million multicellular species, with some estimates running far higher once microbes are included. That means perhaps 70–90% of Earth’s species remain undescribed. 

The real issue is therefore not whether uncertainty exists, but whether deep-sea mining can be governed transparently under enforceable environmental standards. That is a governance challenge, not evidence that seabed mining is inherently unmanageable.

The “dark oxygen” hypothesis

One of the most widely publicised recent objections to deep-sea mining is the so-called “dark oxygen” hypothesis. The claim emerged from experiments conducted in the Clarion–Clipperton Zone in which sealed chambers, or “box experiments”, were placed over sections of seabed containing polymetallic nodules. Researchers reported detecting unexpected oxygen increases inside some of the chambers and proposed that electrochemical reactions associated with the nodules might be splitting seawater molecules and generating oxygen in complete darkness, effectively producing oxygen without photosynthesis.

The idea was rapidly amplified by anti–deep-sea mining NGOs and media outlets as evidence that polymetallic nodules might underpin a previously unknown planetary oxygen system. In some public discussions, this quickly evolved into the suggestion that mining nodules could interfere with a hidden life-support function of the deep ocean itself.

The problem is that the underlying science is, at present, extraordinarily weak compared with the scale of the claims being made.

First, the proposed mechanism conflicts with basic electrochemistry and accepted physics. Accepting the hypothesis at face value would require revisiting well-established redox and electrochemical principles, something that all of the peer reviewers of the original work explicitly highlighted.

Second, the experimental evidence itself is highly problematic. The oxygen anomalies were observed inside sealed experimental chambers operating under difficult deep-sea conditions, where contamination, trapped air, sensor drift, deployment artefacts, or leakage are all plausible explanations. Critically, similar oxygen signals appeared in at least one control chamber away from nodule-rich areas, strongly suggesting the source may have been faulty boxes 

Third, and most importantly in science, the findings have not been replicated. Extraordinary claims require repeatable evidence from independent groups under controlled conditions. 

What currently exists is therefore not a proven geochemical process, but a speculative interpretation of anomalous experimental data that remains unreplicated, contested, and physically difficult to reconcile. 

Deep-Sea Mining Based on International Mining Standards

On land, producing nickel, cobalt and copper at scale routinely involves deforestation, permanent land-use change, waste rock, tailings storage, acid mine drainage, heavy water use, contamination and, in some jurisdictions, serious social harms including displacement, child labour and unsafe artisanal mining. Polymetallic nodules do not remove the need for complex metallurgy, but they can avoid many of the most damaging physical impacts of terrestrial mining: topsoil stripping, pit excavation, overburden removal, tailings dams and large freshwater use.

Seen through ICMM and IFC-type standards, the question is not simply “deep-sea mining: yes or no?” but “which set of impacts, under which controls?”. A coherent comparison would assess the reversibility of impacts, the sensitivity of the affected biome, and whether impacts such as plumes, noise and biodiversity loss can be measured, and if the impacts are objectively acceptable by established environmental standards.

Compared to terrestrial mining the deep sea has important advantages. Nodules are already metal-dense and physically pre-concentrated: a single rock on the seabed contains roughly 25–27% manganese and around 2.3–2.4% combined nickel, copper and cobalt, with no barren host rock, overburden or waste rock or tailings. 

That is the context for TMC’s public PFS flowsheet: nodules are smelted into a high-grade nickel-copper-cobalt matte and manganese silicate, then refined hydrometallurgically into battery-grade sulphates, with the manganese silicate sold into steel or ferromanganese markets. The aim is near-zero solid waste by turning essentially the entire nodule into saleable products rather than tailings.

Put plainly: if nodule processing can achieve no overburden, minimal waste rock, zero tailings, near-zero solid processing waste, lower freshwater use and robust environmental monitoring, then deep-sea mining becomes a serious candidate for one of the lowest-impact routes to battery metals currently available. Add a regime in which ISA royalties are transparently channelled into protecting high-value marine areas and repairing existing ocean damage — from coastal pollution to overfishing — and the case strengthens further: the same activity that supplies critical metals with lower marginal harm could also help fund the repair of far more damaging legacies elsewhere in the ocean system.

Existing Industrialisation of the Sea

The idea that the deep ocean is an untouched wilderness entirely separate from industrial civilisation is simply incorrect. Large parts of the sea are already deeply integrated into global systems for trade, communications, energy, food, and security.

As of 2025, roughly 570–600 active and planned submarine cable systems, totalling around 1.5-2 million kilometres, cross the seafloor carrying approximately 99% of all international internet traffic. These cables traverse abyssal plains, continental slopes, and trenches and have done so for decades with relatively little public scrutiny compared with deep-sea mining. Maritime shipping already moves more than 80% of global traded goods, while ship traffic has increased roughly four-fold since the early 1990s, bringing chronic noise, emissions, and collision risks across nearly all ocean basins.

Fishing has had even larger physical impacts. Industrial bottom trawling along continental margins and some deep-water environments has been shown to reduce deep-sea meiofauna abundance by roughly 80%, cut biodiversity by around 50%. Military infrastructure has also occupied the deep ocean for decades, from submarine patrols to Cold War listening networks such as SOSUS, with hydrophone chains and monitoring systems anchored across deep-water sound channels.

In shallow and coastal waters, marine mining is already routine. Sand and aggregate dredging for cement, concrete, glass, and land reclamation removes billions of tonnes of sediment annually, making sand extraction one of the most widespread human activities in coastal seas after fishing. Heavy mineral operations extract zircon and titanium-bearing sands from beaches and nearshore seabeds, while marine diamond mining off Namibia vacuums placer deposits directly from the continental shelf. Importantly, these activities occur in coastal and shelf ecosystems that are far richer in biomass and biodiversity than abyssal nodule fields.

Set against this reality, abyssal nodule mining would not represent the industrialisation of a previously untouched ocean, but the expansion of industrial activity into a biome that is, by any objective measure, far poorer in biomass and structurally simpler than the coastal and shelf systems humanity already exploits extensively. The striking asymmetry is that this proposed activity faces extraordinary moral and regulatory scrutiny, while far larger and often more destructive uses of the ocean have become broadly normalised. Any coherent environmental standard should at least acknowledge that contrast.

Conclusion

Deep-sea mining sits at the uncomfortable intersection of the mineral imperative and the politics of the global commons. The same energy transition intended to reduce climate risk is driving steep increases in demand for nickel, cobalt, copper, manganese, and rare earths. For now, those metals come overwhelmingly from land: from laterites in Indonesia, copper belts and cobalt mines in the Democratic Republic of Congo and Zambia, ionic clays containing rare earths in Malaysia and Chian, Lithium in the Atacama desert and copper sulphide districts across Latin America and beyond. The supply chains feeding batteries, wind turbines, AI infrastructure, electrification, and modern militaries are already shaped by deforestation, tailings dams, water stress, social conflict, geopolitical concentration, and growing resource nationalism.

Deep-sea nodules and REY-rich muds do not remove those trade-offs, but they fundamentally change the geometry. Here is a potential source of critical minerals requiring no blasting, no pit excavation, no mountain removal, no overburden stripping, and no permanent road systems cutting through forests or populated regions. Multiple critical metals occur together in a single rock resting loose on the seabed in some of the lowest-biomass environments on Earth. The central question is therefore not “mining versus no mining”, but which mining system, in which environment, and with which consequences.

Importantly, humanity already industrialises the ocean extensively. We dredge coastlines, trawl continental shelves, drill offshore oil and gas wells, lay submarine cables across the deep seabed, extract marine aggregates, and move the overwhelming majority of global trade across the sea every day. The deep ocean is not an untouched museum separated from industrial civilisation; it is already embedded within the infrastructure of the modern economy. The question is not whether humanity uses the ocean, but whether future seabed resource development is governed transparently and strategically, or pushed into fragmented geopolitical competition.

This is where the growing paralysis around the International Seabed Authority becomes critical. NGO led moratoriums and “precautionary pauses” increasingly risk transforming the ISA from a regulator into a de facto veto mechanism. Yet capital, industrial demand, and strategic competition do not disappear because regulators stall. Much like The Metals Company has already done,  prolonged paralysis may simply encourage companies and states to move outside ISA-controlled international waters altogether and toward Exclusive Economic Zones, bilateral agreements, or non-ISA-aligned jurisdictions. In practice, attempts to indefinitely delay seabed mining won’t stop it, but instead ensure it develops through fragmented national competition rather than coordinated international governance.

Ultimately, deep-sea mining is not really a debate about whether humanity should extract minerals. That question was answered the moment industrial civilisation chose electrification, digital infrastructure, modern transport, mass industrialisation, and rising material living standards. The real question is where the next marginal tonne of metal should come from, under what standards, and with what comparative impact. The mineral imperative does not disappear because it is politically inconvenient. Modern economies are physical systems built from copper, nickel, cobalt, manganese, lithium, rare earths, steel, cement, hydrocarbons, and electricity. If the world refuses to develop new mineral frontiers, it is not choosing a world without mining; it is choosing intensified dependence on existing terrestrial systems, greater geopolitical concentration, higher resource nationalism, and growing material scarcity. The deep sea is therefore not a choice between nature and industry, but another difficult decision about how an industrial civilisation manages the material foundations on which it depends.