The promise and risks of deep-sea mining

The metals in those nodules can be used to build electric vehicle (EV) batteries, cell phones, solar panels and other electronic devices. They are separate from rare earths, a group of 17 metals also used in EVs.

With climate change escalating, governments are under pressure to rein in emissions – especially from the transportation sector, which was responsible for about 20% of global emissions in 2022.

By 2040, the world will need to use twice the amount of these metals as it is using today in order to meet global energy transition targets, according to the International Energy Agency. And the world will need at least four times today's amount in reaching net-zero greenhouse gas emissions.

Many of the minerals that go into making an EV are becoming harder to find on land, pushing up mining costs in recent years. That's increased prices for EVs and other electronics after they had fallen for years up to 2020. A typical EV needs six times more minerals in total than a vehicle powered by an internal combustion engine.

The hunger for minerals from electronics manufacturers will soon dwarf existing supply. Demand for copper, for example, is expected to double by 2050 to 53 million metric tons each year, but supply will run short by some 2.7 million metric tons unless new sources are unlocked, S&P Global consultancy estimates. This tenuous supply is expected to make copper more expensive.

The scarcity and rising demand has made some governments and companies eager to allow mining in the oceans, which cover more than 70% of the planet’s surface.

First discovered by British sailors in 1873, the potato-shaped polymetallic nodules take millions of years to form as minerals in the seawater precipitate onto pieces of sand, shell fragments or other small materials.

Minerals are also found near deep-sea hydrothermal vents, where they’re called vent sulfides, and within seamounts known as ferromanganese crusts. Processes for extracting these minerals are similar to land-based mining, but harder to do underwater. That’s partly why the nodules are so appealing.

The mining industry has long had a mixed reputation on land. While it supplies the materials used to build our modern lives, it has contributed to deforestation, produced large amounts of toxic waste and in some parts of the world has fueled a rise in child labor. In 2019, a tailings dam — a structure that stores the muddy waste byproduct of the mining process — collapsed and killed hundreds of people at an iron ore mine in Brazil.

The average grade of mines on land — that is, the percentage of minerals extracted with every metric ton of rock — has declined over the last decade, requiring miners to dig deeper to extract the same amount of minerals.

All of these factors make deep-sea mining more appealing, supporters say. Environmentalists, however, say it’s a false dichotomy, as land mining will continue whether or not deep-sea mining is allowed.

Any country can allow deep-sea mining in its territorial waters, and Norway, Japan and the Cook Islands are close to allowing it. The International Seabed Authority (ISA), which is backed by the United Nations, governs the practice in international waters. The ISA missed a July 2023 deadline for setting standards for acceptable sediment disturbance, noise and other factors from deep-sea mining – a bureaucratic misstep that now allows anyone to apply for a commercial mining permit while the ISA continues negotiations.

"What are the alternatives if we don't go to the ocean for these metals? The only alternative is more land mining and more pushing into sensitive ecosystems, including rainforests," said Gerard Barron, CEO of Vancouver-based The Metals Co, the most-vocal deep-sea mining company and one of 31 companies to which the ISA has granted permits to explore for - but not yet commercially produce - deep-sea minerals.

Other companies with exploration permits include Russia's JSC Yuzhmorgeologiya, Blue Minerals Jamaica, China Minmetals, and Kiribati's Marawa Research and Exploration. Their potential future activities are seen as augmenting mining on land.

The Metals Co — which is backed by metals giant Glencore — plans to use the robot to vacuum polymetallic nodules off a vast plain of the Pacific Ocean between Hawaii and Mexico known as the Clarion-Clipperton Zone (CCZ).

The company wants the ISA to set deep-sea mining standards, but said it reserves the right to apply for a commercial permit after July 2024 if the regulatory process stalls again. The ISA has said its work may not finish before 2025.

Companies need ISA members to sponsor them before they can apply for exploration or commercial permits. The island nation of Nauru, which is slowly being engulfed by the Pacific Ocean and sees deep-sea mining as key to the world's energy transition, has sponsored The Metals Co.

Slowing the pace of climate change will be key for climate-vulnerable countries like Nauru if they hope to have a chance of adapting.

"Our existence is being threatened by the global climate crisis," said Margo Deiye, Nauru's ambassador to the United Nations and ISA. "We don't have the luxury of time. This is quite a new nascent industry. Having clear guidelines in place, including standards, would be really helpful."

Data from the U.S. Geological Survey and others show that the CCZ - which covers roughly 1.3% of the world's ocean floor - contains more nickel, cobalt and manganese than all on-land deposits, a staggering volume that supporters say shows the practice should move forward. For copper, the CCZ's deposits are roughly equal with those on land.

Multiple companies have been collecting small numbers of nodules as part of their robot tests in the Abyssal Zone, the part of the ocean below 2,000 meters. One such study is being conducted during November. If the ISA grants The Metals Co a commercial permit, the nodules will be sent to a refinery in Japan where the metals will be processed. The company says it will sell all parts of the nodules and thus there will be no waste byproduct beyond extraneous sand.

The Indian Ocean and parts of the Pacific Ocean are also rich in mineral deposits.

A March 2023 study conducted by the metals consultancy Benchmark Mineral Intelligence found that The Metals Co's plans for the CCZ would cut mining emissions by at least 70%. The study focused on seven criteria, including contributions to ozone depletion and global warming. The study did find that on-land cobalt mining used less water, however. “We’re not talking about mining all of the ocean,” said Barron of The Metals Co, which funded the Benchmark study but said it had no control over its results. “We're talking about one little patch.”

Decades of research has shown that deep sea mining could harm marine life or ecosystems. For example, sediment plumes kicked up by the robotic vacuum could disrupt animal migrations, according to one study published in February in Nature Ocean Sustainability.

The full importance of the nodules within the ocean ecosystem is unclear, and nodule regrowth could take millions of years. The nodules provide homes for anemones, barnacles, corals and other life forms, while bacteria and other invertebrates thrive on the ocean floor.

“These nodules are essential ecosystem architects. If you remove the nodules, you will remove the architecture supporting the entire oceanic ecosystem,” said Beth Orcutt, an oceanographer at Maine's Bigelow Laboratory for Ocean Sciences who participated in the ISA standards debate.

As the world’s hunger for metals and minerals to go green increasingly clashes with the realities of the mining process, the deep sea has become the latest focal point. Ultimately, manufacturers aim to create a circular “closed-loop” system, where old electronics are recycled and their metals are used to build new products.

But reaching that goal is expected to take decades. Debate about whether sensitive ecosystems on land should be dug up have empowered deep-sea mining advocates. Some companies competing with The Metals Co believe that the robotic vacuum is the problem, and are offering potential solutions.

The startup Impossible Metals has developed a robotic device with a large claw that collects nodules as the claw glides along the seafloor. Using artificial intelligence, the robot’s claw is able to distinguish between nodules and aquatic life, the company says.

"From day one, we are focused on preserving the ecosystem,” said Jason Gillham, the CTO of Impossible Metals. However, while the Impossible Metals robot is battery-powered, its energy comes from a diesel generator on a ship at the ocean’s surface, fueling charges that the company’s methods are not fully green.

A Japanese company plans to start mining next year in territorial waters controlled by Tokyo. Chinese officials have acknowledged they lag behind other nations in the deep-sea race, but are vowing to vigorously compete in this "new frontier for international competition." China is already exploring a massive part of the Pacific seabed west of Hawaii - an area that dwarfs the CCZ. Norway, already a prolific offshore oil producer, is on track to be the first country to allow deep-sea mining if its parliament approves, as expected, plans to mine hydrothermal vents.

For now, the ISA's members are hotly debating the best standards for deep-sea mining.

"Nothing we do will have zero impact," said Joe Carr, a mining engineer with the metals consultancy Axora. "We're going to need mining for the green energy transition."