Dangers of deep seabed mining

The sea floor between Hawaii and Mexico is covered in potato-sized rocks that contain many metals needed to make electric-car batteries. All that’s needed is a way to lift them to the surface for processing. At least, that’s the theory behind The Metals Co, a business formed earlier this year when the Canadian startup DeepGreen merged with a special-purpose acquisition company. As this company prepares to go public, it’s touting seabed mining as a green alternative to land-based mineral extraction—and potentially a hugely lucrative business.

Not everyone is quite so optimistic. Since June, 530 marine-science and policy experts from 44 countries have signed a statement warning that seabed mining would result in environmental damages “irreversible on multi-generational timescales." That should alarm not just investors, but policy makers charged with protecting the oceans.

The Pacific basin is thought to contain more than 30 billion tonnes of so-called polymetallic nodules, rocks that are rich with cobalt, copper, manganese, nickel, rare-earth elements and titanium.

Scientists and entrepreneurs have been researching methods of extracting them since the 1960s. In 1994, the International Seabed Authority was established to regulate mining efforts and protect the seabed environment. Any of the group’s 167 member-states can stake claims to mining concessions on the ocean floor and sponsor private companies to explore them. But the ISA has not yet completed, much less approved, any regulations. So far, it has only handed out permits for exploration. And for good reason.

The deep seabed is arguably the least resilient ecosystem on the planet. In 1989, researchers dragged a plough that mimicked a mining operation across the deep Pacific; some three decades later, many of the life-forms affected by the experiment have yet to recover.

Mining polymetallic modules would likely have much worse consequences. The damage wouldn’t be confined to the ocean floor. Plumes of sediment kicked up by mining operations could persist for months, with dire effects on sea life accustomed to clear water. Douglas McCauley, a professor at the University of California at Santa Barbara, warns the plumes might also include toxins. “Those could connect to my own dinner plate as seafood," he told me. “Tuna could feed on them, and that’s a $1 billion industry." The plumes might also reduce the ocean’s ability to sequester carbon—or even release stored carbon into the atmosphere—thereby worsening climate change.

Research into these impacts and whether it’s possible to mitigate them (McCauley thinks not) has been underway for years. Unfortunately, the clock is ticking. The ISA had planned to complete a code for exploiting resources by the end of 2020. As meetings were cancelled during the pandemic, that date was pushed off. Then, in late June, the small Pacific nation of Nauru (population: 9,770), invoked its right under the group’s rules to request a fast-track adoption of mining regulations within two years. If the rules can’t be finalized by then, mining will likely move ahead.

Plenty of interested parties stand to benefit. In the meantime, a pause on deep-sea mining would surely make sense. If the ISA and its members won’t commit to that, then the UN should call for a moratorium, and countries (or businesses) with commercial interests at stake should consider challenging any permits at the International Tribunal for the Law of the Sea and other legal forums. Few industries have ever had the potential environmental impact of seabed mining. Policymakers need to ensure that the consequences don’t sink us all.