The real problem with deep-sea mining is it won’t make money

As if the world wasn’t in enough trouble from the warmest week ever measured and record-low sea ice around Antarctica, big business is already gearing up to ransack yet another unspoiled corner of the globe: the deep ocean.

The International Seabed Authority, or ISA, the United Nations body that regulates exploitation of the deep sea floor, will decide in the next few weeks on an application by the Pacific island state of Nauru to open up mining 5 kilometers (3 miles) below the Pacific.

Environmental groups are united in opposition. The plan will “destabilise delicate ocean ecosystems,” according to the World Wide Fund for Nature, and “rip up the seabed for profits,” in the words of Greenpeace. The
European Academies of Science Advisory Council, an association of science policy specialists, called last month for a moratorium on the practice.

That shouldn’t restrain the ISA from giving the go-ahead. If it could be made to work, deep-sea mining would benefit a planet that will have an insatiable hunger for critical minerals as it decarbonises over the coming decades. It could even provide an economic lifeline for some of the island nations most at risk from rising sea levels. The problem isn’t environmental, but economic: Even if it’s authorised, we’re unlikely to see any large-scale shift of mineral exploitation to the ocean floor.

The target would be polymetallic nodules, potato-sized rocks strewn over the seafloor that are rich in manganese, nickel, copper and cobalt — metals so essential to the nascent electric-vehicle industry that the nodules have been likened to “batteries in a rock.” Though they have been known about since the 19th century, to date, the closest the world has come to exploiting them was a bizarre Cold War caper in which Howard Hughes set up a fake nodule mining company as cover for a CIA operation to recover a sunken Soviet nuclear submarine.

Advances in technology have since brought this kind of mining to the brink of viability. The oil industry, which had barely started to exploit anything but the shallowest seas until the late 1990s, now commonly drills wells in waters more than 3 kilometers deep. That’s close to the 4km-6km depth of nodule deposits. Machines similar to vacuum cleaners would suck the nodules off the sea floor, separate them from sediment, and pump them up to ships for processing.

It’s undeniable that this would involve damage to vast areas. Extracting enough minerals to produce a billion electric vehicles would disturb half a million square kilometers of the ocean floor, more than three times the area consumed by doing the same thing on land, according to one 2020 study.

However, anyone who thinks we can extract minerals without disturbing pristine ecosystems should take a look at the existing mining industry. The world’s richest iron ore deposit, Brazil’s Carajas, is in the middle of the Amazon. The biggest producer of both nickel and coal is Indonesia, whose sprawling open-cast mines and attendant waste piles are carved out of the pristine forests of Borneo, Sumatra, Sulawesi and the Maluku islands. One of the world’s busiest coal shipping channels goes straight through the lagoon of Australia’s Great Barrier Reef.

Mining as a whole is barely noticeable when set next to the vast areas dedicated to agriculture, with the entire global industry using about the same amount of land as is utilised for growing oats. Bottom-trawling fishing, meanwhile, disturbs about 4.9 million square kilometers of the sea floor every year to provide diners with shrimp and plaice, roughly 10 times what you’d use to build those billion electric cars.

Ecologically, the deep ocean is a desert, whose surprisingly high biodiversity still represents as little as 0.001 percent of the biomass found in shallower waters and on land. The far greater threat to biodiversity over the coming decades is climate change itself. A quarter of all marine species depend on coral reefs, which will be almost eliminated from their current ranges at two degrees Celsius (3.6 degrees Fahrenheit) of warming.

The bigger issue with deep-sea mining is more humdrum. Mining projects stand or fall on the quality of the cashflows they can produce, and the most valuable products in a nodule are manganese, nickel and cobalt — minerals whose prices are notoriously volatile, causing major mining companies to largely shun them. That makes it particularly challenging to justify investments, especially those using untested technologies in remote parts of the open ocean.

There are no major land masses close to the Clarion-Clipperton Zone in the central Pacific, the most promising spot for nodule exploitation. If you think drilling for oil in the Arctic tundra is hard work, extracting and processing millions of tons of rock from 5 kilometers down in the middle of the ocean may be even more challenging. One 2021 study of the economic prospects for such operations found that the potential was seriously limited. Even if the ISA decides to allow deep-sea mining, it may be environmental campaigners who get the last laugh.

David Fickling is a Bloomberg Opinion columnist covering energy and commodities. Views are personal and do not represent the stand of this publication.

Credit: Bloomberg