But much of the key data underpinning that argument was produced by mining companies themselves or published by academic journals with financial interests in the industry, and support for the sector from electric carmakers has waned in recent years as the industry has failed to prove it can mine the ocean floor "in a way that ensures the effective protection of the marine environment," as one statement calling for a moratorium read.
Confronted with growing opposition to the notion that deep-sea mining—in which companies use equipment to comb the habitat of tens of thousands of species and potentially spread mining waste for miles—can serve as a key climate solution, Greenpeace said, "these fickle deep-sea entrepreneurs are jumping ship."
Now "they are eager to embrace politically opportunistic 'national security' storylines," reads the report.
"For TMC, the green transition was always a false narrative," said Arlo Hemphill, project lead for the Stop Deep-Sea Mining campaign at Greenpeace USA. "The numbers just didn't add up to justify opening the world's last unspoiled wilderness to mass-scale extractive exploitation. Now, the industry is repackaging itself as essential to national security and defense, exploiting real geopolitical tensions for personal profit. It's a dangerous and unnecessary strategy that could destroy the international seabed to enrich a few."
The report was released as the International Seabed Authority (ISA) convened in Kingston, Jamaica for its 30th Assembly, with governments under heavy pressure from the deep-sea mining industry to fast-track a Mining Code under which they could move forward with ramping up operations—even as 37 states and nearly 1,000 international scientists now support a moratorium on deep-sea mining.
As the ISA began its meeting on Monday, Pew Environment explained the risks carried by deep-sea mining—from noise and light pollution to the endangerment of species scientists haven't yet discovered.
"The deep sea is one of Earth's most pristine and fragile ecosystems," said Grace Evans, senior associate of ocean governance at Pew Charitable Trusts. "Once we damage it, we can't go back."
TMC began "targeting defense and industrial policy stakeholders" in 2022 as it was still pushing its green energy transition narrative.
The company spent nearly half a million dollars over two years to hire lobbying firms to influence votes on the National Defense Authorization Act (NDAA) in 2023 and 2024—and succeeded in pushing the Department of Defense (DOD) to deliver a report "assessing the processing of seabed resources of polymetallic nodules domestically."
TMC's lobbying push also convinced 31 Republican members of Congress to write to then-Defense Secretary Lloyd Austin in 2023, asking him "to develop a plan to address the national security ramifications of [China's] interest and investment in seabed mining."
In March, TMC announced it would seek permits from the U.S. to mine the international deep sea under American authorization—a move that "brazenly" bypassed international treaties and consensus, said Greenpeace.
Greenpeace's report comes four months after that application and three months after President Donald Trump signed an executive order signaling the government's intent to "rapidly" develop and invest in U.S. capabilities to explore and collect seabed mineral resources through "streamlined permitting," with the White House asserting the U.S. "has a core national security and economic interest in maintaining leadership in deep-sea science and technology and seabed mineral resources."
"We will not stand by while a neocolonial deep-sea land grab takes place that will harm our communities, disrupt our cultural connection to the ocean, and endanger our livelihoods."
Under the order, the Trump administration signaled its "readiness to unilaterally authorize deep sea mining in both U.S. and international waters," reads the Greenpeace report—potentially violating the United Nations Convention on the Law of the Sea, which the U.S. has not signed.
Days after the order was signed, TMC applied to the U.S. government for deep-sea mining exploration licenses and commercial mining permits. The Greenpeace report details how the Trump administration and companies including TMC are working together to once again promote a false narrative about the necessity of deep-sea mining—one that is actually meant to provide "a lifeline for an industry in crisis."
Global defense industries "likely represent only a tiny fraction of overall global consumption" of the metals found in polymetallic nodules in the deep sea, according to the report—meaning that as with the electric auto industry, the defense sector's true demand for deep-sea mining is much smaller than the industry and the Trump administration would have the public believe.
"The U.S. defense demand stands for a tiny percentage of our domestic consumption of critical metals. And to be honest, U.S. defense is not a big user of anything," Jack Lifton, executive director of the Critical Minerals Institute, told Greenpeace. "Given what the defense industry and the DOD and the different contractors are doing in terms of securing metals from elsewhere, friendshoring, reshoring, recycling, there is no need to mine the seabed for cobalt or nickel or rare earths."
While metals that can be accessed through deep-sea mining do have military uses, "the scale of this military use is relatively modest compared to global civilian demand—dwarfed by the commercial manufacturing sector," reads the report.
For example, the U.S. currently imports manganese ore from Gabon, South Africa, and Mexico, and "a substantial deep sea mining development could nearly double the global supply of manganese in its first year, resulting in an immediate oversupply" and a reduction in the value of the metal and the global mining operation. The U.S. also already has a stockpile of 322,000 tons of manganese in Arizona.
In a foreword to the Greenpeace report, retired U.S. Army Major General Randy Manner wrote that "the bedrock of national security" lies in "global stability, the rule of law, and ecological resilience"—not in accumulating new minerals and weaponry.
"Mining the deep ocean in defiance of international consensus would degrade all three. It would erode U.S. credibility, fracture alliances, and set a dangerous precedent for unilateral resource exploitation," said Manner.
In the Pacific region—where deep-sea mining companies aim to operate—several states and leaders have called for a ban. moratorium, or precautionary pause on the practice, with Pacific Island Heritage Coalition Chair Solomon P. Kaho'ohalahala warning that "the Pacific is not a sacrifice zone."
"We will not stand by while a neocolonial deep-sea land grab takes place that will harm our communities, disrupt our cultural connection to the ocean, and endanger our livelihoods," said Kaho'ohalahala. "This July, ISA member states must make it clear where they stand—for their foundational principles of equity, multilateralism, and environmental protection or unbounded corporate greed."
At the ISA meeting in Kingston, Greenpeace International campaigner Louisa Casson said governments around the world "have sent a clear signal that the deep-sea mining industry will not get international approval any time soon"—even amid industry pressure and the Trump administration's push.
TMC's application to the U.S. "shatters" the firm's credibility "and serves as a stark warning to others considering this reckless path."
"Governments have also reaffirmed that there should be no deep sea mining in the global oceans while major political and scientific questions remain unresolved," said Casson. "Deep sea mining is a dangerous gamble we cannot afford, and the only responsible way forward is a global moratorium."
