Deep-sea mining: benefits and risks

The clean-energy transition depends on critical minerals. Batteries, wind turbines, solar panels and electricity grids all require large volumes of metals such as nickel, cobalt, copper, manganese, lithium and rare earth elements. But extracting these materials on land is often environmentally damaging, socially controversial and geopolitically concentrated.

One possible source lies at the bottom of the ocean.

What is the trend?

The deep seabed is increasingly seen as a potential source of critical raw materials for the energy transition. Supporters of deep-sea mining argue that collecting minerals from the ocean floor could reduce pressure on forests, farmland and communities affected by land-based mining.

For Europe, the issue is especially strategic. The EU Critical Raw Materials Act aims to strengthen domestic extraction, processing and recycling capacities by 2030 and reduce dependence on single-country suppliers. Yet Europe still relies heavily on imported critical raw materials, which makes supply chains vulnerable to geopolitical shocks.

At the same time, many governments, scientists and companies argue that the ocean floor should not become the next frontier of extraction before the environmental risks are properly understood. The deep sea remains one of the least studied ecosystems on Earth. Mining it could cause damage that lasts for decades – or even longer.

What are polymetallic nodules, and why do they matter?

Polymetallic nodules are rounded mineral formations found on the seabed. They usually grow around a small core, such as a shell fragment, shark tooth or piece of organic material. Over millions of years, metals dissolved in seawater slowly accumulate around that core.

Their growth is extremely slow: roughly a few millimetres to one centimetre per million years.

These nodules contain metals such as manganese, nickel, cobalt and copper – all important for batteries, electric vehicles, renewable energy infrastructure and industrial technologies. They are found at depths of around 3,500 to 6,500 metres, including in the Clarion-Clipperton Zone in the Pacific Ocean, one of the most discussed regions for future deep-sea mining.

Interest in polymetallic nodules has existed since at least the 1960s and 1970s. But the current wave of attention is driven by the rapid growth of clean technologies and the need to secure critical mineral supply chains.

The argument for deep-sea mining

Supporters say deep-sea mining could help meet growing demand for critical minerals without expanding destructive land-based mining.

On land, mining for cobalt, nickel and other metals can require deforestation, open-pit excavation, large volumes of water and chemical processing. These activities can pollute soil and water, destroy biodiversity, release stored carbon and damage the livelihoods of nearby communities.

Some mining regions have also been linked to serious human-rights concerns, including unsafe working conditions and child labour.

From this perspective, collecting nodules from the seabed may appear less harmful than opening new mines on land. There are no villages to relocate, no forests to clear and no agricultural land to remove from use.

But this comparison is incomplete.

Why deep-sea mining is risky

The main concern is that deep-sea mining would disturb ecosystems that are extremely fragile, slow to recover and still poorly understood.

Mining machines would remove nodules from the seabed, disturb sediment and potentially create underwater plumes. These plumes could spread fine particles across large areas, smother marine organisms, affect filter-feeding species and change the physical and chemical conditions of the ocean floor.

Noise, light and wastewater discharge from mining operations could also affect deep-sea life. Many species living in these environments are adapted to darkness, high pressure, low temperatures and very stable conditions. Some may exist only in specific habitats that have not yet been fully mapped.

There is also a long-term habitat problem: the nodules themselves are part of the ecosystem. They provide hard surfaces for marine organisms in otherwise soft sediment environments. Because nodules take millions of years to form, removing them is not comparable to harvesting a renewable resource. In practical terms, the habitat loss could be permanent on human timescales.

A 2025 Nature study found that the impacts of a small experimental deep-sea mining disturbance were still visible 44 years later. Some signs of biological recovery were observed, but the affected communities remained altered. This suggests that industrial-scale mining could create ecological changes lasting for many decades.

Regulation is still unresolved

Commercial deep-sea mining in international waters is governed by the International Seabed Authority, or ISA. As of early 2026, the ISA had 31 exploration contracts in force: 19 for polymetallic nodules, eight for polymetallic sulphides and four for cobalt-rich ferromanganese crusts.

Exploration, however, is not the same as commercial exploitation.

The ISA has not yet finalised the full Mining Code that would regulate commercial mining. Key issues remain unresolved, including environmental safeguards, liability, benefit-sharing, monitoring and compensation for damage.

The first part of the ISA Council's 31st session took place in Kingston, Jamaica, in March 2026. It did not approve commercial exploitation activities, and the regulatory framework remained unfinished.

A moratorium until the science is clearer

Many scientists argue that humanity does not yet know enough about the deep ocean to begin commercial mining responsibly. A global marine expert statement calling for a pause on deep-sea mining has been signed by hundreds of scientists and policy experts from more than 75 countries.

Several governments have also called for a precautionary pause, moratorium or ban. The list includes European countries such as France, Germany, Spain, Sweden, Finland, Portugal, the United Kingdom, Austria, Ireland and others.

Major companies, including Google, BMW, Volvo and Samsung SDI, have also supported calls for a pause or committed not to use minerals sourced from deep-sea mining until the risks are better understood.

The debate is therefore not only about minerals. It is about the kind of transition the world wants to build.

A clean-energy system cannot be considered truly sustainable if it simply shifts environmental damage from forests and communities on land to poorly understood ecosystems at the bottom of the ocean. The energy transition needs critical minerals, but it also needs stronger recycling, better product design, material efficiency, alternative battery chemistries and more responsible sourcing.

Deep-sea mining may one day become technically possible. The harder question is whether it can ever become environmentally responsible.

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