In 1972, a young ecologist named Hjalmar Thiel ventured to a remote part of the Pacific Ocean known as the Clarion–Clipperton Zone (CCZ). The sea floor there boasts one of the world’s largest untapped collections of rare-earth elements. Some 4,000 metres below the ocean surface, the abyssal ooze of the CCZ holds trillions of polymetallic nodules — potato-sized deposits loaded with copper, nickel, manganese and other precious ores.

Thiel was interested in the region’s largely unstudied meiofauna — the tiny animals that live on and between the nodules. His travel companions — prospective miners — were more eager to harvest its riches. “We had a lot of fights,” he says.

Now, it seems this nascent industry’s time has come. A growing demand for batteries to power electric cars and to store wind and solar energy has driven up the cost of many rare-earth metals and bolstered the business case for sea-bed mining.

Both scientists and conservationists, however, are worried that the creation of regulations will encourage the industry to start mining long before there is enough information on how operators can avoid causing serious environmental harm. The scarce data that exist suggest that deep-sea mining will have devastating, and potentially irreversible, impacts on marine life.

Seabed Mining is Coming — Bringing mineral riches and fears of epic extinctions