Since 1779 photosynthesis has been the standard-issue explanation for the continuation of life on earth: plants absorb sunlight, which fuels their metabolism, and create oxygen as waste. This is such basic, grade-school science that it normally wouldn’t bear mentioning, but in July 2024 a team led by Andrew Sweetman at the Scottish Association for Marine Science reported a startling finding in Nature. On the deep seafloor—where light never penetrates—oxygen is apparently being produced by rocks.

These rocks are known as polymetallic nodules, which form over the course of millions of years when small debris like sharks’ teeth attract trace metals from the surrounding seawater. The seafloor is covered in a viscous ooze, composed of the compressed skeletons of dead marine life, and the nodules lie strewn atop it, packed closely together. Sweetman and his team were investigating the microbial life in this deep-sea environment by lowering custom-designed chambers into the depths, creating a seal around seafloor sediment. Generally, the oxygen within the chambers decreases as various organisms consume it. In the nodule fields, against all odds, oxygen levels were rising.

Rocks don’t photosynthesize, and Sweetman, assuming his equipment was faulty, sent it back to the manufacturer. The manufacturer returned it, insisting nothing was wrong. After taking nearly a decade of these readings, Sweetman realized that the nodules could possibly be splitting seawater into hydrogen and oxygen through a natural form of electrolysis. Much about this process is unclear: the oxygen could be generated by some sort of arcane microbial process, rather than electrolysis, or a mixture of both, and it’s not known whether the production of what the paper calls “dark oxygen” is continuous, or if the instruments the team uses to gather data are somehow triggering the nodules to release more oxygen. Sweetman himself handled the unexpected results warily: “That paper was written to say, ‘Hey guys, there’s oxygen production where there shouldn’t be. We need to explore it in greater detail,’” he told me, explaining that the oxygen’s actual function in deep-sea ecosystems was still a total mystery.

But the questions raised by his discovery posed an immediate problem. Among those funding the research were Lockheed Martin and a mining outfit called The Metals Company (TMC), both of whom have been interested in harvesting polymetallic nodules for their constituent metals: cobalt, nickel, iron, and manganese. The companies presumably intended for Sweetman’s work to result in a fairly anodyne baseline study of the seafloor; instead, it may make history. No sooner had his team issued their findings than TMC issued a rebuttal, alleging “selective reporting of data to support extraordinary claims.” Some independent geologists also expressed skepticism, albeit outside of peer review: Science reported that, for instance, one geochemist found it worrying that there was “no sign of elevated oxygen in the waters above the nodule region.”

Undaunted, Sweetman is embarking on another study early next year to confirm his results, this one sponsored by the Nippon Foundation and the JPI Oceans Mining Impact 3 project. (He’s also investing, he said, laughing, in bulletproof vests.) But the response his research provoked offers a glimpse into the increasingly antagonistic debate around seabed mining, which includes nodule harvesting as well as other forms of exploitation, such as stripping cobalt-rich crusts from seamounts. The companies involved have long presented theirs as an ecofriendly industry, an alternative to dirtier forms of extraction and their attendant human rights violations. “Corporations let people down,” the CEO of The Metals Company, Gerard Barron, told me when we spoke in 2020. “We never want to be that.” Environmental advocates and many researchers have dismissed such claims as greenwashing and warned about the enormous risks of mining the ocean, from disrupting the carbon cycle to precipitating a large-scale die-off of marine life. But Barron has found a powerful ally in the Trump administration, which has signaled that it intends to start licensing mining operations in international waters. This time around, The Metals Company declined to comment when I reached out.

Heraldic visions of the green transition still figure prominently in the mining companies’ rhetoric. But as the journalist Elizabeth Claire Alberts has shown in a detailed two-part investigation into The Metals Company for Mongabay, those claims have been overtaken as of late by warnings about national security: we need these minerals not just for batteries and solar panels but for the military as the administration ratchets up its rhetoric against China. For the first time since 1990, the Department of Defense has begun stockpiling cobalt, used for alloys in munitions and jet engines. Nickel is in the armor plating on tanks and anti-aircraft firearms. “They’re no longer making decisions based on profitability,” Linwood Pendleton, an environmental economist and the executive director of the Ocean Knowledge Action Network, told me about the US’s strategic goals. “When you start talking about things in terms of national security, all costs are reasonable—even if it means the collapse of the ocean. At least we have weapons.”

*

The seafloor is relatively young in comparison to the continents, constantly swallowing itself along subduction zones and regurgitating magma from the Earth’s crust and mantle. But polymetallic nodules form on the abyssal plains—flat expanses, far from the geologic drama of the Mid-Atlantic Ridge, that are so environmentally static that any change whatsoever registers as a monumental event. The waters above the nodule fields are some of the clearest in the ocean, and teeming with life: sponges, worms, corals, and fish, as well as a lively microbial community that could be critical to medical advances such as new antibiotics and cancer drugs. Although nodules’ exact role in ecosystems remains unknown, on the vast fields of ooze they serve as the only hard substrate to which corals, sponges, and anemones can attach.

National Oceanic and Atmospheric Administration

Manganese nodules on the seafloor of the southeastern US continental margin, off the coasts of South Carolina, Georgia, and Florida, 2019

The ocean outside of territorial waters, known somewhat ominously as “the Area,” is more than fourteen times the size of Russia and comprises a little more than half the seabed. It falls under the jurisdiction of the International Seabed Authority (ISA), an intergovernmental organization headquartered in Kingston, Jamaica. The ISA was established at the 1982 UN Convention on the Law of the Sea, where it was given a conflicting set of mandates to protect and safeguard the sea and its resources as “the common heritage of mankind,” while also administering ocean exploitation. It has since issued thirty-one contracts to states to explore mining sites, mostly in the Clarion-Clipperton Zone (CCZ), a nodule-rich area of the Pacific between Hawaii and Mexico. Should mining commence just on these tracts that have already been licensed, it would cover a larger geographic area by far than any other extractive industry on the planet.

And yet mining companies have thus far been stuck in limbo, unable to start work until the ISA establishes a mining code that will determine environmental standards for this enormous enterprise. Agreeing on those standards has proven to be a sticking point, as has coming up with a scheme for distributing the profits. Under the current regime, mining companies cannot simply strike out on their own—they must represent an ISA member state. TMC, for example, represents Nauru, Kiribati, and Tonga, which hold claims to several large tracts in the Clarion-Clipperton Zone. Because deep-sea resources are considered “common heritage,” the Law of the Sea stipulates that a small portion of the profits from every mining operation be distributed equally throughout the world, although how that would happen exactly is unclear.

Thus far the ISA has made relatively slow progress toward a mining code, despite strong pro-mining influence. The former secretary general, Michael Lodge, was so supportive of the burgeoning industry that he appeared in a promotional video for the company that would become TMC, but a significant contingent of the 171 member states have called for a moratorium on the practice until its environmental impacts are better understood. Lodge’s successor, the Brazilian oceanographer Leticia Reis de Carvalho, is widely seen as more circumspect; she took office in 2024 with a vow to investigate her predecessor for his troublingly close relationship to the industry.

The United States never signed the Convention on the Law of the Sea, put off by the idea of sharing profits and wary of giving too much power to the UN. John Bellinger, a senior legal advisor for the State Department under the George W. Bush administration, spent years trying to convince lawmakers to get on board (his children made him a button one Christmas that read “Please ask me about my treaty”), only to be repeatedly stymied by the Heritage Foundation, which dissuaded a number of Republican senators from joining Bellinger’s cause. “Why can’t US companies just go engage in oil and gas exploration or deep-seabed mining without us joining the convention?” conservative senators asked him. In other words, Bellinger explained to me, “Why buy the cow if you can get the milk for free?”

The practical answer is that it is illegal under international law. The Law of the Sea is generally seen as the “constitution of the ocean,” and even nonmember states are expected to abide by its rules and regulations, which govern not only mining but also international fishing, shipping routes, and the boundaries of exclusive economic zones. As the delegate from China pointed out when the ISA convened in July, for decades the US has in fact benefited from this state of affairs: by extending all countries’ proprietary waters two hundred miles from land, the Law of the Sea gave the US access to extensive offshore oil and gas reserves that might otherwise be contested.

But this year the US nonetheless decided to strike out on its own. In late April President Trump issued an executive order for the National Oceanic and Atmospheric Administration (NOAA) to fast-track the permitting process for mining in international waters, citing the 1980 Deep Seabed Hard Mineral Resources Act (DSHMRA)—a legal regime that preceded the Law of the Sea and was only intended to provide interim guidelines.

Undermining the treaty could turn the ocean into a free-for-all, which has infuriated ISA member states. Any country could decide to extend its territorial waters five or six hundred miles from shore, industrial fishing would become a battlefield, and miners would begin a mad rush to exploit the seafloor with no guarantee of confining themselves to the areas they’ve already licensed from the ISA. Oversight of the industry, meanwhile, would become nearly impossible. The Trump administration has made clear that it has little to no interest in environmental regulation, and the ISA does not have the resources to monitor vast tracts of seafloor. “It would render the high seas completely and totally lost,” said Matt Gianni, cofounder of the Deep Sea Conservation Coalition. “Ultimately, tensions and conflicts would probably end up being dealt with by force.”

*

Ever since deep-sea mining first began to gain ground in the 2010s, miners have tried to justify their uncertain new industry by pointing to the urgent need to reduce emissions. That was how Gerard Barron framed the issue when we spoke in 2020: “I always talk about it as a global public good.” Barron, an Australian, had worked in advertising for years before becoming an early investor in one of the first commercial deep-sea mining operations, Nautilus Minerals, which had its sights set on sulfides in seamounts off Papua New Guinea but went bankrupt after environmental pushback, a shortage of investor interest, and a legal dispute with the host country over its equity stake. Not long after the company went public, as Alberts recounts, Barron pulled out and invested in a new deep-sea mining company, DeepGreen, founded by the former Nautilus CEO in Vancouver.

Barron took over as CEO in 2017 and embarked on an enthusiastic PR campaign, telling me five years ago that he wanted to be part of “this new category of corporations that will be measured on a whole variety of things. Not just whether they make money or not, but how they treat the planet, how they choose developing partners, how they help address sustainable development goals.” For DeepGreen to be successful, Barron said, he’d “have to approach it with the environment at the forefront.” Not everyone was convinced. In late 2020 DeepGreen’s former lead environmental scientist alleged in a now-deleted LinkedIn post that Barron and the rest of the company’s executives had “minimal respect for science, marine conservation, or society in general.” (In a statement to Bloomberg, the company called his claims meritless.) “Don’t let them fool you,” the scientist wrote. “Money is the game.”

Carolyn Cole/Los Angeles Times/Getty Images

Gerald Barron, the CEO of The Metals Company, in front of a Maersk vessel on which the firm was conducting research on the seafloor, San Diego, California, 2021

In 2021 DeepGreen went public and changed its name to The Metals Company, although it stuck with its original method of nodule collection: a vacuum more than twice the size of a minivan that would cruise along the seafloor. Current research suggests that using this system to even gently remove the nodules could drastically alter the ecosystem. A recent study in Nature, which looked at a mining test site from the late 1970s, showed both that deep-sea life is very slow to recover once disturbed—some amoeba-like creatures had returned to the area, but larger creatures that live on the seafloor, such as corals and sponges, were absent from the operations’ tracks—and that the long-term consequences of mining are difficult to effectively predict. A 2022 study in Science found that noise pollution from mining operations could extend for hundreds of miles, interfering with marine life that uses sound to communicate. Just last month another Nature study concluded that waste particles discharged in the course of mining would be “likely to disrupt midwater food webs” for zooplankton and small swimming organisms.

When mining companies do acknowledge such risks, they tend to make the case for deep-sea extraction as a necessary alternative to the costs of terrestrial mining—child labor in the cobalt mines of the Congo, for example, or the destruction of the rainforest in Brazil. Here, they say, is an extractive industry that causes no black lung, no hilltops blasted to hell, no methane flares, no tailing ponds, no poison in the groundwater. And yet the idea that deep-sea mining will replace existing industries seems “neither economically nor politically plausible,” as another recent article in Nature argued. Seabed minerals are not strictly needed for the green transition, according to a 2024 briefing from Zero Carbon Analytics, and this has only become more true as battery technology advances to using sodium iron phosphate, which requires neither nickel nor cobalt. Current critical mineral needs have been aggravated by how wastefully terrestrial mines operate: a copper mine, for example, will toss any material that isn’t copper. A recent study in Science found that a year’s worth of lithium lost in mining waste in the US could power ten million electric vehicles.

Undergirding much of the debate about deep-sea mining is the question of just how much we know about the seafloor itself. “You often hear NGOs cite, ‘We know more about the moon than we do the ocean,’” I was told this year by Oliver Gunasekara, the CEO of the California-based company Impossible Metals, which was founded in 2020 to provide more ecologically friendly equipment to deep-sea miners but has since become a miner itself. “It’s completely false.”

Gunasekara points to the gigabytes of raw data in the ISA’s open databases as evidence that it has sufficient information to create guidelines for seafloor exploitation. TMC, in a recent public statement, made a similar claim: the company had commissioned enough research and gathered enough data about the Clarion-Clipperton Zone to yield “a high-resolution understanding of what lives down there.” But an abundance of data does not make that data interpretable, and one of the greatest dangers of this nascent industry is that we may not even have instruments precise enough to fully understand what kind of changes mining will bring. Biologists estimate that less than 10 percent of ocean species have been identified; only .001 percent of the seafloor has been seen by man.

Impossible Metals proposes mitigating the potential damage from mining using artificial intelligence: the company is building robots that would hover above the seafloor, avoid nodules with life on them, and use mechanical arms to pluck others, leaving a certain percentage behind to keep the ecosystem stable. (Interest in such moonshot solutions is something of a theme with Impossible Metals—Gunasekara has also suggested using Sam Altman’s cryptocurrency, WorldCoin, to distribute the shared profits from mining globally.) “Hovering above the seafloor is a nice concept,” Beth Orcutt, a senior research scientist at Bigelow Laboratory for Ocean Sciences, said when I mentioned it to her. “It’s really hard to do in practice without disturbing things.” Gianni was more dismissive: “it’s more science fiction than reality.”

Even if the machines were able to hover with the necessary care and alacrity, for Impossible Metals to remove 40 percent of this delicate ecosystem—its targeted proportion—would do a substantial amount of harm, according to every researcher I spoke to. Orcutt warned that the damage done to the ecology of the seafloor by removing the nodules “would essentially be permanent, based on the information that’s available today.”

It’s hard to overstate the potential implications of disturbing the ocean’s ecology. About three billion people rely on fish as a source of protein. The ocean absorbs roughly a third of humanity’s carbon emissions and produces half of the world’s oxygen. If deep-sea mining contaminates the mid-water column, it could cause a significant die-off of marine life that would threaten global food systems; if churning up the seabed makes it more difficult for the ocean to store carbon, it could exacerbate climate warming; as for deep-sea ecology, mining’s potential long-term effect is still largely unknown. As Orcutt put it, “We would only know there’s a problem when there are no animals.” Many nations have already concluded that the risks of such disasters far outweigh the benefits of mining. Forty states have called for at least a pause on the industry; French President Emmanuel Macron instated an outright ban, calling the rush to mine “madness.”

*

In 2021 The Metals Company—on behalf of the tiny, island nation of Nauru, which has been all but destroyed by phosphate mining—triggered a clause in the UN Convention of the Sea that obligates the ISA to produce mining regulations within two years. When that deadline came and went, TMC complained to the ISA that it was facing “escalating legal and financial risks” due to the ongoing delays. Gianni pointed out to me that the company’s 2024 year-end report showed it bleeding funds. By the end of 2024 it had less than $3.5 million in cash on hand; loans from Barron were helping keep it afloat. As recently as this past March, Oceanographic Magazine was suggesting that deep-sea mining had “run out of road.”

Trump’s reelection seemed to open up a new path. In March TMC announced that it intended to petition the United States for a mining permit in the Clarion Clipperton Zone, throwing its relationship with the small island nations into question and issuing what Alberts calls “a striking challenge to the international legal regime for dealing with seabed mining rights.” Five days after Trump signed his executive order, the company followed through on that promise, applying for a pair of exploration licenses and one “commercial recovery permit,” which would allow them to begin operations. Impossible Metals applied for an exploration permit as well, although they stopped short of seeking a US license to mine in international waters, limiting their request to an area of roughly 73,000 square kilometers in US territory near American Samoa. In September they sought an international mining permit from the ISA, under the sponsorship of Bahrain.

TMC’s application hardly means that it can start mining tomorrow. NOAA has begun the process of streamlining licenses for exploration and exploitation; the public comment period closed in September, and they’ll likely announce their findings by the end of the year. But even if all goes according to plan, Gianni says, it would likely take about a year for the US to establish its own regulations. Even with a highly expedited regulatory process, as Barron acknowledged on the company’s third-quarter earnings call, TMC is looking at a late 2027 start date by their own accounting. This puts Barron in relatively dangerous territory, because without the Trump administration it’s not clear that his gambit will find much support. Even if the company receives an exploitation license from NOAA, which has only ever licensed exploration, it could be invalidated under the next administration—all it would take is a president slightly less interested in upending the global order.

Making matters still more uncertain for TMC is its increasingly precarious relationship with the ISA. In July the council adjourned the second half of its annual convention with an announcement that it would be investigating the company to determine whether it violated the Law of the Sea by requesting a mining license from the US. If it did, the ISA could decide to terminate or suspend TMC’s exploration contract with Nauru when it comes up for renewal next July; its contracts with Tonga and Kiribati would be similarly endangered. Should the council terminate the contracts, TMC would depend entirely on the US’s interest in unilateral mining. In the meantime, the council also announced that it had finally decided to do away with the rule imposing the two-year deadline for establishing a mining code, instead opting to begin building a checklist of issues that require further study before regulations can be finalized. They’re aiming to finish that checklist at their next meeting in March.

The Metals Company is not the only outfit that wants mining to begin, but if it does move ahead under a US license it will set itself against the rest of the world. China, Gianni explains, could make a territorial bid for the whole of the contested South China Sea, Russia could expand their influence in the Arctic, and any country could impose unilateral requirements around global shipping. On the other hand, if ISA member states did abide by the Law of the Sea while the US began mining, those states would be bound by the council’s decisions and obligated to deny entry to defectors, which would bar TMC from using many international ports. The blowback could also extend to investors such as Allseas, which is supplying TMC with the Hidden Gem, a ship it is using to conduct tests.

National Oceanic and Atmospheric Administration

A crab traversing a field of ferromanganese nodules on the seafloor of the Gosnold Seamount, one of a string of extinct volcanoes off the coast of Massachusetts, 2021

Insurers, too, have taken notice of the industry’s fragility. Hannover Re, Zurich Insurance Group, Vienna Insurance Group, and Swiss Re now prohibit any underwriting of deep-sea mining, standing alongside thirteen major banks. It’s possible that miners could band together to create a mutual fund, like those that serve maritime shipping, but it seems unlikely that TMC will find enough partners to cover the risks its actions entail. The company did not respond when asked how they planned to obtain insurance.

It does, however, seem probable that mining will go ahead within US territorial waters. Impossible Metals is not the only company to seek a deep-sea mining lease within those bounds; a former treasure-hunting company based out of Tampa now holds an exploration permit near the Cook Islands, and more may follow. The public comment on Impossible Metals’s proposal closed August 15, and Samoan officials made it clear that they were uniformly against the industry. “Our waters are not isolated,” Sabrina Suluai-Mahuka, the project director for American Samoa’s climate resilience office, told my colleague, Anita Hofschneider, at Grist, irked by industry officials touting the benefits of mining in “remote” parts of the Pacific. “We live here.”

The territory instated a moratorium in 2024, only for federal officials to blow past it. In November the Trump administration announced that it would pursue mining in waters of the Mariana Islands, and former ISA Secretary Michael Lodge made an appearance at the Underwater Minerals Conference in Florida to call DSHMRA—the legislation cited in Trump’s executive order—“a very good piece of legislation…based on sound legal and scientific fundamentals which have not changed that much.” It was, said Barron on TMC’s third-quarter call, “a tremendous speech.”

*

In 1967 Arvid Pardo, a Maltese diplomat who would become known as the father of the Law of the Sea, gave a quite different speech, a three-hour address in front of the United Nations General Assembly. “The dark oceans were the womb of life,” he said.

Retracing the past, man, the present dominator of the emerged earth, is now returning to the ocean depths. His penetration of the deep could mark the beginning of the end for man, and indeed for life as with know it on this earth. It could also be a unique opportunity to lay solid foundations for a peaceful and increasingly prosperous future for all peoples.

Pardo was concerned that developed nations would overrun the ocean as mining became more technologically feasible, widening the gulf between rich and poor countries. His draft of the law proposed requiring countries to share the financial benefits derived from resources within their two-hundred-nautical-mile limit internationally: the entirety of the offshore oil industry, for example, would be regarded as common heritage. He was powerfully disappointed by the Law of the Sea that came into being, which he called “probably the most inequitable treaty that has ever been signed in the world.”

When the treaty was signed, mining was considered imminent, yet nearly a decade later the industry remained in limbo. Environmental concerns had not yet come to the forefront, and the prevailing understanding of the deep sea was of a graveyard, devoid of all life. But the intractable problems preventing agreement on a system for exploiting the Area were similar to what they are today. In a long feature in Newsday, one writer explained:

There is a serious information gap that limits current decision-making. If a delegate asks, “What’s in it for my country?” on an issue, he may honestly answer himself with an “I really don’t know.” Many political arguments are being advanced without the knowledge of technology and the economic costs and benefits required for each state to identify its own interests. This problem is further confused because the situation is so changeable…. The stakes in the game are high. Failure to agree on a workable regime for the oceans—even a temporary one—opens up a Pandora’s box of possible consequences no country wishes to contemplate.

All this should sound familiar. Despite Barron’s bluster, it may be the same old tactical problems of technology and international relations that hamstring The Metals Company. “What the Trump administration is risking is so far beyond what they could gain,” said Gianni. “I think saner heads—if there are some within the administration—might recognize we need to back off.”

Whether or not what Bloomberg calls one of the industry’s “most aggressive” actors goes under, the existential threats that come with seabed mining remain so disturbing that even experienced economists speak about the idea like it carries a curse. “There are certain things that, to me, seem to be things we should not go after—anything that nature puts two thousand meters down in the ocean,” Rashid Sumaila, a professor of ocean and fisheries economics at the University of British Columbia, told me. He got the sense the miners felt otherwise. “They think I’m crazy,” he said. “They see the money, they’re going for it.”