The race for metals at the bottom of the sea

The vast resources found on the seabed, often surpassing terrestrial reserves, have drawn the attention of countries like China, Japan, South Korea, and India, whose industries heavily rely on these minerals. The race to secure these minerals has become a central issue in geoeconomic competition, with the US, EU, Japan, and South Korea seeking to reduce their dependency on China, which dominates much of the low-carbon technology supply chains. However, the increased demand has raised concerns about the environmental impact of seabed operations and the effectiveness of current regulatory frameworks in mitigating these impacts.

What resources are found?
The seabed hosts three mineral formations of interest for extraction: polymetallic nodules (or "manganese nodules"), cobalt crusts, and sulfides. Each of these formations has unique conditions of formation and properties.

Polymetallic nodules. These nodules contain high concentrations of manganese, nickel, copper, and cobalt. Found in deep basins with low sedimentation rates, the seabed "grows" at an extremely slow pace—up to 1mm every thousand years. This slow process allows the formation of nodules through the very gradual precipitation of metals on the seafloor. The extraction process involves disrupting the upper layer of sediment and removing the nodules.

Cobalt crusts. These typically measure between 10 and 15 centimetres in thickness (though they can reach up to 25 centimetres) and coat the slopes of underwater mountains in the western Pacific Ocean at depths ranging from 800 to 2,500 metres.

Polymetallic sulfides. Found in areas with volcanic activity and seafloor spreading, near tectonic faults, these formations are clusters of gold, zinc, lead, copper, and rare earth elements.

How Is deep-sea mining regulated?
Deep-sea mining is governed by the United Nations Convention on the Law of the Sea (UNCLOS) and the International Seabed Authority (ISA). UNCLOS defines seabeds outside national jurisdictions as the "common heritage of humanity," requiring an international mining code to regulate exploration and exploitation of resources. The ISA, comprising 169 countries and the European Union and based in Kingston, Jamaica, oversees 54% of the world’s seabeds and grants specific licences for mineral exploration—issued only after thorough approval processes—to public or private entities interested in surveying the mineral wealth of the deep ocean. However, negotiations for adopting a mining code have stalled due to disagreements among member states, particularly concerning environmental protection. On one hand, the precautionary approach introduced in the 1992 Rio Declaration guides ISA policies to prevent environmental harm even in the absence of scientific certainty. On the other hand, economic pressures from states and companies eager to exploit seabed resources could undermine these measures, influencing global governance at the expense of sustainability. The ISA is also tasked with considering the cumulative impacts of mining activities on a broader scale beyond directly affected areas. Yet, the lack of quantitative data and a solid scientific foundation makes it challenging to develop effective regulations and adequate monitoring strategies to mitigate environmental impacts.

In January of this year, the Norwegian parliament secured a majority to approve a plan to open the Barents Sea and the Greenland Sea to seabed mining exploration. Backed by its advanced geological knowledge and offshore drilling technologies, Norway justified the initiative as support for the "energy transition." In this context, global governance of these activities could give way to individual nations’ interests, raising significant long-term questions about the protection of oceanic seabeds.

Environmental impact: a fragile ecosystem at risk
Seabeds are largely unexplored environments, often perceived as ‘uninhabited’ due to their depth and lack of light. Contrary to common belief, the deep ocean teems with life and hosts some of the highest concentrations of biodiversity on the planet. The same minerals sought after are integral components of these ecosystems and underpin the oceanic food chain. It is estimated that over 230,000 species inhabit these environments, and studies suggest that mining could lead to the extinction of many known and yet-to-be-discovered species. The long-term effects remain unclear, but estimates indicate that marine communities could take decades or even centuries to recover—if they recover at all. Biodiversity loss, the dispersion of toxic sediments, and the disruption of vital ecological processes (even those affecting land, such as carbon storage) are among the primary concerns highlighted by scientific studies.

During mining operations, sediment plumes could spread over vast areas, up to 100 kilometres from the extraction site, clogging natural filters and reducing food availability for microbial communities crucial to ecosystem health, with potential consequences for climate change. Certain microorganisms play an essential role in regulating the carbon cycle and sequestering methane, a potent greenhouse gas, and their presence on polymetallic nodules helps stabilise ocean chemistry by removing toxic metals from the water.

The idea of extracting resources from the deep ocean also conflicts with the transition to a circular economy, which aims to increase recycling and reduce resource use. According to the WWF report "The Future is Circular," technological innovation and a circular economy could reduce the demand for critical minerals by 20 to 58% by 2025. Considering that by August 1 (Earth Overshoot Day), humanity had consumed the resources available for an entire year, it becomes evident that transitioning to a circular model is the only way to secure future resources.

In light of the environmental implications of deep-sea mining, it is clear that we face a critical choice. On one hand, the ecological transition requires metals and resources abundantly found on the ocean floor. On the other hand, deep-sea ecosystems represent one of the planet’s last relatively untouched natural frontiers—only 5% of which has been topographically mapped—and their exploitation could lead to irreversible consequences.