Minerals such as lithium, cobalt, nickel and rare earth elements are essential ingredients in everything from wind turbines and electric vehicles to cell phones, medical technologies and military infrastructure. Mining for these materials on land is already well established, but with demand surging, some are now looking to tap the seafloor for its millions of square kilometers of metal ores.

Some countries and companies have already begun exploring underwater mineral deposits and mining techniques — but the prospect of deep-sea mining remains controversial. Despite years of research, little is known about the deep ocean. Many fear that extracting minerals from it could pose grave consequences for both marine life and planetary health.

While nations can currently pursue deep-sea mining in their own domestic waters, the world is still awaiting exploitation regulations from the UN's International Seabed Authority (ISA) that will dictate whether and how it could proceed in international waters, where the bulk of the ocean's critical minerals are found.

With the future of deep-sea mining still under debate, here's what we know so far about the proposed practice and its impacts — and what we don't:

1) What Is Deep-Sea Mining and How Would It Be Done?

Deep-sea mining aims to retrieve valuable mineral deposits found on the ocean's floor, hundreds or even thousands of meters below its surface. Alongside a diverse array of marine life at these depths are significant reserves of copper, cobalt, nickel, zinc, silver, gold and rare earth elements.

In the deep sea, these minerals are contained within slow-forming, potato-sized polymetallic "nodules," as well as in polymetallic sulfides (large deposits made up of sulfur compounds and other metals that form around hydrothermal vents) and metal-rich crusts on underwater mountains (seamounts). While there has been commercial interest in these minerals for decades, recent advancements in technology have made it feasible to mine these areas by sending vehicles down to harvest mineral deposits from the seafloor.

Polymetallic nodules that look like small rocks on the floor of the deep sea.
Mineral nodules on the seafloor in the Clarion-Clipperton Zone, a key area of interest for deep-sea mining. Photo by ROV KIEL 6000/GEOMAR

In the case of polymetallic nodules — which are currently the primary focus for deep-sea mining in international waters — mining vehicles would remove mineral deposits from the surface of the seabed, along with the top layers of sediment, using a suction device not unlike a vacuum cleaner. The materials collected would then be piped up to a surface vessel for processing. Any waste, such as sediments and other organic materials, would be pumped back into the water column.

The bulk of the most attractive mineral deposits are found on vast seafloor abyssal plains in international waters. One area of particular interest is the Clarion-Clipperton Zone in the Pacific Ocean. This mineral-rich region already hosts exploration contracts for 17 deep-sea mining contractors, with their combined exploration areas covering approximately 1 million square kilometers (about the same area as Egypt).

Map showing where large reserves of critical minerals are located in the deep ocean, primarily in the Pacific.

2) What's the Current Status of Deep-Sea Mining?

While exploratory mining to test equipment has occurred at a small scale, deep-sea mining has not yet been undertaken commercially. But some national governments and mining companies plan to begin as soon as possible.

A few countries have already approved permits to explore mineral resources in their own domestic waters (known as "exclusive economic zones," or "EEZs"). However, most deep-sea mining interest is concentrated in international waters, which means the industry's future will largely hinge on how the ISA decides to regulate it. After years of negotiations, the ISA is due to adopt a final set of regulations in July 2025 that will govern responsible commercial mining operations in international waters.

Opinion remains deeply divided on whether deep-sea mining should be allowed at all. Given the insufficiency of information on how it could affect marine environments, countries such as Germany and Canada, as well as the European Parliament, have called for national and regional moratoria on deep-sea mining. Portugal recently passed a law banning the practice in its national waters for the next 25 years.

Meanwhile, Canadian mining company The Metals Company announced in March 2025 that, through a U.S. subsidiary (The Metals Company USA LLC), it had begun the process of applying for licenses and permits under the U.S. National Oceanic and Atmospheric Administration's mining code, known as the Deep Seabed Hard Mineral Resources Act of 1980 (DSHMRA). This pathway is possible because the U.S. has not ratified the UN Convention on the Law of the Sea (UNCLOS), under which the ISA sits. Hence the U.S. is not an ISA member and is not bound by ISA processes.

This could potentially accelerate the timeline for commercial deep-sea mining by circumventing the ISA's permitting process altogether. Depending on the outcome of The Mining Company's application, other companies may follow this route, undermining international efforts to secure shared standards.

3) What Are the Potential Benefits of Deep-Sea Mining?

Proponents of deep-sea mining argue that it can help meet the world's pressing need for critical minerals, which will likely only continue to grow as countries invest more in decarbonization, digitization, defense and infrastructure. Estimates suggest that global demand for nickel, cobalt and rare earth elements may double by 2040 in a net-zero emissions scenario. Several studies have concluded that there is no shortage of mineral resources on land, but the world still faces significant hurdles in locating viable reserves and quickly scaling up mining and processing operations.

Some also view deep-sea mining as an alternative pathway that can circumvent certain risks associated with mining on land. Since extraction would occur exclusively at sea, deep-sea mining is unlikely to be associated with environmental hazards such as deforestation and freshwater pollution that can impact communities neighboring terrestrial mines. Yet others argue that infrastructure built to process and transport deep-sea minerals would require land acquisition and development, which may impact local communities' property, food sources and lifestyle.

Similarly, the difficulty in accessing deep-sea mineral deposits for exploitation means that artisanal (small-scale) mining operations would be impossible, and strong regulation of labor conditions may be feasible. This could potentially avoid the human rights abuses associated with some terrestrial mining operations. However, experiences of labor abuse in distant-water fishing operations show this outcome is not guaranteed.

4) What Are the Risks of Deep-Sea Mining?

While the deep sea was once thought to be devoid of life — too dark, cold and starved of food for anything to survive — we now know that it is the largest habitable space on the planet and home to a dazzling array of life. To date, tens of thousands of species have been found in the deep ocean. Estimates say there could be millions more. In the Clarion-Clipperton Zone alone, a key area of interest for deep-sea mining, researchers have recently discovered over 5,000 species that were entirely new to science.

A bright pink starfish on the floor of the deep ocean among small, potato-shaped mineral nodules.
A starfish in a field of manganese nodules on the seafloor in the Clarion-Clipperton Zone. Thousands of previously unknown deep-sea species have already been discovered in this area, which some seek to mine for its mineral resources. Photo by ROV-Team/GEOMAR

With exploration and testing still in the early stages, further research is needed to determine the possible ecological impacts of deep-sea mining. But the science to date paints a concerning picture.

  • Direct harm to marine life: There is a high likelihood that less mobile deep-sea organisms would be killed through direct contact with heavy mining equipment deployed on the seabed, and that organisms would be smothered and suffocated by the sediment plumes these machines are likely to create. Warm mining wastewater could also kill marine life through overheating and poisoning.
  • Long-term species and ecosystem disruption: Mining activities could impair the feeding and reproduction of deep-sea species through the creation of intense noise and light pollution in a naturally dark and silent environment. For example, the sound pollution from these activities could negatively impact large mega-fauna like whales, posing further risk to populations already strained by climate change and other human activities. Because many deep-sea species are rare, long-lived and slow to reproduce, and because polymetallic nodules (which may take millions of years to develop to a harvestable size) are an important habitat for deep-sea species, scientists are fairly certain that some species would face extinction from habitat removal due to mining, and that these ecosystems would require extremely long time periods to recover, if ever.
  • Possible impacts on fishing and food security: It's not just the seafloor that's at risk. Under current designs, waste discharge from mining vessels could spread over large distances, potentially kilometers away from the areas being mined. This may pose a threat to open ocean fish and invertebrates which are crucial to international fisheries — such as tuna stocks that help drive the economies of small island developing states like Kiribati, Vanuatu and the Marshall Islands. Effects of this mining waste could include suffocation, damaged respiratory and feeding structures, and disrupted visual communication within and amongst species, alongside changes in the oxygen content, pH, temperature and toxicity of seawater. However, more research is needed on the characteristics of the discharge plumes themselves and the tolerance of ocean species to fully understand these impacts.
  • Social and governance risks: While extraction would occur offshore, the deep-sea mining industry would still need shoreline facilities for processing and transshipment of material. This would require land acquisition and development, which has historically driven habitat loss affecting coastal communities that depend on marine resources. Though the UN has designated high-seas minerals "the common heritage of [hu]mankind" and declared that any mineral extraction should benefit all nations, the current regulatory regime of the ISA appears to promote the flow of mining profits to developed states, or to shareholders of mining companies, rather than being inclusive of developing nations.
  • Potential climate impacts: The ocean is the world's largest carbon sink, absorbing around 25% of all carbon dioxide emissions. Microscopic organisms play a critical role in this climate-regulating system, helping to sequester carbon in the deep sea and reduce emissions of other planet-warming gases (such as methane) from seabed sediments. The loss of deep-sea biodiversity following mining activity may impact the ocean's carbon cycle and reduce its ability to help mitigate global temperature rise.

5) Is Deep-Sea Mining Necessary?

The global supply of critical minerals (including rare earth elements) must grow in the coming years, and quickly. But there is no easy answer to meet this demand responsibly given the immature state and potential dangers of mining at sea and the well-understood harms associated with mining on land. While mineral resources on land appear sufficient to meet global needs, the world must address how to responsibly scale up supply in a way that minimizes environmental, social and governance risks while also creating benefits (such as safe, good-paying jobs) for nearby communities.

Circularity is an important pathway to meet the demand for minerals while reducing dependency on new mining. IEA estimates that significantly scaling up recycling could reduce the need for newly mined minerals by 40% for copper and nickel and 25% for lithium and cobalt by 2050. For some minerals, such as lithium and battery-grade nickel, the share from recycling will remain low for another 5-10 years before end-of-life EV battery volume starts to rise. For other minerals, such as copper and cobalt, there is already opportunity to scale recycling today, since they are widely used in many sectors such as electronics and infrastructure.

Better recycling practices in established waste streams, such as from electronics and electrical equipment, can help alleviate some short-term supply pressure while preparing the secondary supply chain to handle a large volume of end-of-life zero-carbon energy products in the future. There is also a range of research efforts underway to obtain the necessary minerals without mining virgin land, including recovery from coal waste or hard rock mine tailings.

How technology evolution is changing demand for minerals should also be considered. Take batteries as an example: There is a growing shift away from nickel manganese cobalt oxides (NMC) batteries toward lithium iron phosphate (LFP) batteries. LFP batteries gained significant market share from 2015 to 2022, and their key materials, lithium and iron, are not targets of deep-sea mining. Emerging technologies such as sodium-ion batteries also have the potential to alter the EV battery market by replacing lithium and cobalt with cheaper, more abundant options.

With Serious Questions Still Unanswered, What Comes Next?

After failing to reach an agreement at previous meetings, the ISA is aiming to finalize regulations for commercial mining during its 30th session in July 2025. It is crucial that the regulations fully consider the following key questions and knowledge gaps:

  • What is the potential magnitude and extent (both in space and time) of deep-sea mining impacts on marine species and environments, and what are the likely ecological consequences?
  • What are the potential social and economic impacts of deep-sea mining? Is it possible for the industry to be advanced in a way that meets the UNCLOS goal of fostering sustainable economic development, international cooperation and equitable trade growth for all countries?
  • How can a circular mineral economy be further developed to lessen the need for environmentally intrusive practices? More research must be conducted into land-based and urban mining practices to improve their efficiency, as well as into improving product design to reduce demand for and increase recycling of critical minerals.
  • What are the possible positive and negative implications of deep-sea mining in achieving the UN Sustainable Development Goals, as well as for furthering research into deep-sea environments?
  • What regulations could be developed to ensure that the financial benefits from deep-sea mining operations, should they occur, are equitably distributed among nations?

Finally, for the exploration of deep-sea mineral resources to continue, regulations should be transparent and collaborative, with participation from interested parties and key stakeholders — including ISA members, mining corporations and scientists. The regulations need to be backed by science and other forms of knowledge, enforceable, and offer effective protection for delicate marine environments from the impacts of mining.

Editor's note: This article was originally published in July 2023. It was last updated in April 2025 to reflect developments in deep-sea mining policy.