Day 140 — Reading: The Race for Deep-Sea Metals

A The transition to renewable energy and electric vehicles has sharply increased global demand for a small number of metals, including cobalt, nickel, manganese and copper, all of which are essential components of batteries and other clean-energy technologies. As accessible land-based deposits of these metals become scarcer and more expensive to extract, mining companies and some governments have turned their attention to an unlikely source lying on the ocean floor: polymetallic nodules, potato-sized rocks rich in exactly the metals the green transition requires.

B These nodules form exceptionally slowly, growing by only a few millimetres every million years as minerals dissolved in seawater precipitate around a fragment of shell or rock. The largest known deposits lie scattered across the seabed of the Clarion-Clipperton Zone in the Pacific Ocean, at depths of between 4,000 and 6,000 metres. To harvest them, mining companies deploy large collector vehicles that crawl slowly across the ocean floor, using suction or mechanical arms to gather nodules before pumping them, mixed with seawater and sediment, up a riser pipe to a surface vessel.

C Proponents of deep-sea mining argue that it offers a cleaner alternative to some forms of land-based extraction. Nodules typically contain a higher concentration of valuable metals than many land ores, meaning that less material needs to be processed to yield the same quantity of metal. Advocates also point out that a significant share of the world's cobalt currently comes from artisanal mines in the Democratic Republic of Congo, where labour conditions, including the use of child labour, have drawn international criticism; shifting extraction to the seabed, they argue, could reduce reliance on such supply chains.

D Marine scientists, however, warn that the environmental risks of seabed mining remain poorly understood and potentially severe. The deep sea hosts slow-growing, long-lived organisms adapted to a stable, dark environment, and many species found on and around nodule fields exist nowhere else. Once a collector vehicle disturbs the seabed, the sediment plumes it generates can drift for many kilometres, smothering filter-feeding organisms and altering water chemistry far beyond the immediate mining site. Because deep-sea ecosystems recover so slowly, researchers estimate that damaged seabed communities could take many decades, or even centuries, to return to anything resembling their original state.

E Responsibility for regulating mining in international waters falls to the International Seabed Authority, or ISA, a United Nations-affiliated body that has spent more than a decade negotiating a draft Mining Code that has yet to be finalised. Several Pacific island states and environmental groups have called for a moratorium on commercial seabed mining until its ecological impact is better understood, while some mining companies and other governments argue that a two-year procedural rule obliges the ISA to consider mining applications even before regulations are complete. This disagreement reflects a deeper tension at the heart of the debate: whether the economic opportunity presented by seabed metals should be pursued now, or whether environmental precaution should take priority until the risks are better known.

F The outcome of this debate remains uncertain. Improvements in battery recycling and the development of technologies that require smaller quantities of critical metals could eventually ease pressure on both land and seabed sources, but neither is expected to eliminate demand in the near term. Whatever is decided, the way the ISA and its member states resolve the question of deep-sea mining is likely to set an important precedent for how humanity governs the vast areas of ocean floor that lie beyond any single nation's jurisdiction.