Does The Ocean Floor Hold The Key To The Green Energy Transition?

Abundant minerals at the bottom of the ocean could be vital for renewable energy infrastructure. But what harm will be caused by mining them?

Juliana Toro for Noema Magazine

Charlotte Elton is a journalist based in London. She has written for In These Times, The Big Issue and Euronews.

Just 200 meters beneath the surface of the ocean, the murky “twilight zone” begins. It’s dark there — the water absorbs and scatters the sun’s rays to the point of near-imperceptibility. Venture 800 meters farther and sunlight no longer penetrates at all, marking the beginning of what’s known as the “midnight zone.”

Descend further still — down, down, down, past luminous sea butterflies, fangtooth fish and species of nearly blind octopi — and soon enough you’ll hit the sea floor. If you’re lucky, you might touch down next to an ancient sea sponge. Researchers estimate that the oldest sponges have been alive for perhaps 10,000 years, predating the oldest human civilizations by around five millennia.  

But the inhabitants of some parts of the gloomy ocean deep face an existential threat. The seabed contains vast deposits of precious metals, an untapped resource that mining companies and others claim could turbocharge the renewable energy transition. In July, the International Seabed Authority (ISA) — the body tasked with governing seabed mining — met to hammer out extraction regulations. After three weeks of intense debate, the meeting concluded without a clear agreement. The future of the seabed is uncertain.

Clinging to rocks and other hard surfaces that jut out from the sea floor, a sponge — no matter how ancient — might not look like much of a reason to halt a hugely lucrative endeavor, especially one that might fuel the green transition to a more sustainable world above. But probe a little deeper and this strange animal invites us to think about how we might live in harmony with each other on our planet — and what is at stake if we do not.

“The seabed contains vast deposits of precious metals, an untapped resource that mining companies and others claim could turbocharge the renewable energy transition.”

An Underwater Rainforest And Its Mineral Wealth

What’s caught the eye of intrepid mining companies looking at the seafloor are billions of tons of polymetallic nodules. These lumpy, potato-sized nuggets are formed through complex and agonizingly slow biochemical processes — over a million years, they expand at a rate of just 1-3 millimeters — and are packed with nickel, cobalt, manganese and other rare metals. Since 2001, the International Seabed Authority has issued 31 permits to private companies and state-owned enterprises trying to explore the ocean floor with a view to eventually exploiting these reserves. 

As the world becomes increasingly reliant on battery technology to fuel the green transition, the race to the depths of the sea is heating up. In 2021, the tiny island nation of Nauru announced its intention to dig up nodules within a 1.7 million square mile region of the Pacific known as the Clarion-Clipperton Zone. The country’s declaration triggered what’s known as the “two-year rule,” giving the ISA just 24 months to finalize an environmental rulebook for mining. 

The deadline was July 9 this year — but after weeks of heated negotiations, the ISA pushed it back to at least July 2025. The outcome disappointed companies eager to commence operations. But it wasn’t a straightforward victory for conservationists: Several countries called for a temporary pause on all deep-sea mining, but China blocked the debate from reaching the ISA floor. 

The debate has turned bitter. Both the conservationists and the mining advocates claim they are fighting to save the planet. Who should we believe?

Threats To The Ecosystem

The deep sea teems with life, up to 90% of which remains unnamed and undiscovered. Less than 0.01% of the deep-sea floor has been sampled and studied in detail. This pristine ecosystem may contain millions of species — a biodiversity comparable to that of tropical rainforests. Scientists discover new species almost every time they dive down there. 

The unusually stylistic flair of some researchers studying this realm — “bizarre,” “mysterious,” “spectacular” — is a testament to the utter strangeness of these sci-fi-esque creatures. Glass squid float elegantly, bioluminescent light organs disguising their silhouettes from would-be predators. The goblin shark, the last living member of a lineage stretching back 125 million years, sniffs out prey using a special organ on its long snout to detect the weak electrical fields produced by other animals. Barreleye fish gaze upward from eyes situated within translucent heads. Iron-armored snails cling onto searing hydrothermal vents, harvesting toxic chemicals that symbiotic microbes living on them break down for sustenance.

Our ancient sea sponge is somewhere down here, too, filtering 20,000 times its volume in water every single day.

An extraction operation could dredge up thousands of square miles of seabed. Violent strip mining would crush and tear out complex sea flora and choke filter feeders in vast plumes of sediment that stretch for hundreds of miles. Major sound pollution would also occur. Other methods of sea mining — like stripping away the mineral-rich outer layer of seamounts, many of which are underwater mountains formed by volcanic activity — would decimate millennia-old coral and sponges. 

Scientists also argue that mining could also disrupt the ocean’s role as a carbon sink. Since the onset of the industrial era, the oceans have absorbed about a quarter of all human-generated CO2 emissions. Deep-sea mining would loosen ocean-floor sediment, potentially reinjecting carbon stored there back into the ocean, potentially accelerating ocean acidification and global warming.  

Citing such threats, the International Union for Conservation of Nature has called for a moratorium on deep-sea mining. So too has the European Academies’ Science Advisory Council — the continent’s top science panel — and various national governments from France to Fiji. In an open letter, more than 700 marine science and policy experts from over 44 countries have urged the ISA to temporarily ban the practice. “The sheer importance of the ocean to our planet and people, and the risk of large-scale and permanent loss of biodiversity, ecosystems and ecosystem functions, necessitates a pause of all efforts to begin mining of the deep sea,” the letter warned.

“Advocates of deep-sea mining see it as the solution to the climate crisis, not the opposite.”

Green Transition Miracle?

Not everyone agrees. Advocates of deep-sea mining see it as the solution to the climate crisis, not the opposite. 

Electric cars, wind turbines and solar panels rely on vital metals like cobalt, manganese, nickel and copper. Transitioning the global economy to renewables is going to require a vast amount of these precious minerals.

In 2019, the anthropologist Jason Hickel estimated what it will take to decarbonize the global economy: 34 million metric tons of copper, 40 million metric tons of lead, 50 million metric tons of zinc, 162 million metric tons of aluminum and 4.8 billion metric tons of iron. In 2030, the global demand for lithium will likely surpass two million metric tons, doubling the demand forecast for 2025. A swelling fleet of electric cars will further exacerbate the metal deficit.

Plundering the ocean floor is the least harmful route to decarbonization, would-be deep-sea miners claim — including The Metals Company, Nauru’s proposed mining partner. The alternative is to ramp up production on land, polluting soil, devastating wildlife and contributing to human rights abuses. 

Underwater mining means “no disruption to Indigenous communities, no deforestation and no child labor during the mining phase,” The Metals Company’s website declares.

So is deep-sea mining the lesser evil? Surely the green transition is more important than some sea slug. Surely Indigenous communities should take priority over the deep, dark ocean where no human lives. Who would honestly argue that a goblin shark, ancient lineage or not, deserves more protection than a child toiling in a cobalt mine in Congo?

We have to mine, the miners say. Do you want to mine the ocean deep or mine on land? Hit a switch and prevent land degradation and ecosystem devastation. If a few ancient corals get crushed, so be it. 

The Circular Economy

The comparison between land and sea mining is something aspiring ocean mining companies lean heavily on. But “you cannot compare apples and oranges,” Duncan Currie, an environmental lawyer working with the Deep Sea Conservation Coalition, told me. “We do not know the extent or nature of biodiversity loss in the deep sea, so cannot compare it.”  

Mining the deep sea also won’t necessarily lead to the closure of terrestrial mines, he said. “It is not logical to assume opening deep-sea mining in the ocean will lead to the closure of land-based mines. They would be in addition.”

There are other options, and there might also be new discoveries or advancements in materials and technologies that lessen the need for minerals. Promising battery alternatives like graphene aluminum-ion, iron-flow and solid-state technologies are being developed, as well as no-impact extraction directly from seawater. Indeed, many electric vehicle manufacturers like BMW, Volvo, Volkswagen and Renault, support the deep-sea mining moratorium.

These developments have their own problems — aluminum production, for example, can spew chemicals into groundwater — but the impacts are more quantifiable (and therefore manageable) than mining the deep. 

More crucially, we need to shift from a linear economy — in which single use is the norm — to a circular economy where recycling and re-use play a key role. The deep sea isn’t the only untapped reservoir of precious minerals. Much of the vast amount of e-waste consumers produce annually is available to be reclaimed. In a scenario developed by the International Energy Agency to achieve net zero emissions globally by 2050, demand for critical minerals will increase six-fold compared to today. But a 2022 report commissioned by the World Wildlife Foundation found that scaling up recycling can reduce cumulative demand for lithium, cobalt, nickel, manganese, rare earth elements, platinum and copper by more than half.

“The path forward includes a mix of technological innovation and changes to our current patterns of consumption and waste,” then-WWF director general Marco Lambertini wrote in the report. He added: “With human ingenuity and an enlightened sense of self-preservation, this task is well within our collective capacity to achieve.”

In 2022, researchers estimated that 5.3 billion mobile phones were thrown away. Most no longer work, sometimes by design. But it doesn’t have to be this way. Indeed, regulatory solutions already exist. 

Earlier this year, the EU proposed “right to repair” legislation requiring manufacturers to make their products easier to fix. The Paris public prosecutor recently opened an investigation into Apple for preventing consumers from mending their phones with third-party components. And around the world, “repair cafes” and “libraries of things” are springing up to collectivize ownership and fight unnecessary waste. Mandating the provision of extended warranties requires companies to replace defective products, disincentivizing inbuilt flaws. In Sweden, for example, customers have the right to make a guarantee claim up to three years after the point of purchase.

“We have to mine, the miners say. Do you want to mine the ocean deep or mine on land?”

Lessons From A Sea Sponge

In the deep-sea mining debate, the real question is not whether companies should plunder on land versus sea. The question is about how humans look at the natural world: as a naked resource, nothing more than an agglomeration of resources that exist to be ruthlessly exploited? As our home, a place we must protect at all costs or face the consequences? 

At the bottom of the ocean, faceless sea sponges are silently sucking up vast quantities of water. They provide vital services to ocean floor ecosystems, filtering water, recycling waste and producing valuable nutrients for other marine organisms. 

Some specimens are 20 times older than industrial capitalism. They have survived for so long by working with their environment, not against it.