Long tentacles of a Relicanthus stream above the seafloor
Relicanthus, a relative of sea anemones, are reliant on polymetallic nodules in the Clarion-Clipperton Zone, a target of deep-sea mining. Credit: Craig Smith and Diva Amon, ABYSSLINE Project, CC BY 3.0

Advocates of deep-sea mining claim the process is important for providing metals for renewable energy technologies. One of the strongest arguments against offshore mining is that the environmental risks are too high, given that deep-sea ecosystems are among the most undiscovered places on Earth.

A less reported issue is the impact that deep-sea mining would have on developing economies that rely on land-based mining of those same metals. That is the subject of a recent report commissioned by the International Seabed Authority (ISA).

The global seabed area is beyond any national jurisdiction, but ISA regulates mining. To carry out exploratory missions, state-backed companies must obtain an ISA license, which grants exclusive access to seabed areas of up to 150,000 square kilometers. To date, 30 licenses have been issued, with China holding the most, with five. The United States is not eligible for licenses, as it is not an ISA member state, but U.S. defense firm Lockheed Martin has a license through its U.K. subsidiary.

The report names 13 nations, the majority in Africa, as being most vulnerable to additional metal supplies entering the market. Each identified country currently generates at least 10% of its export earnings from one or more of the key metals targeted by deep-sea mining: copper, cobalt, nickel, and manganese.

The report identifies Zambia, Democratic Republic of Congo, Eritrea, Chile, Lao People’s Democratic Republic, Mongolia, and Peru as vulnerable to a market influx of offshore copper supplies. Copper plays an important role in renewables due to its ability to conduct electricity and heat. Almost all cobalt (used in batteries) is a by-product of copper production, so it could also affect these countries.

The economies of Madagascar and Zimbabwe will be affected by new supplies of nickel, which is expected to play a key role in electric vehicles and high-capacity batteries. Gabon will be affected by new manganese supplies, used in the production of high-grade steel. Mauritania, Namibia, and Papua New Guinea are at risk because of the cumulative effect of all of the specified metals.

Assistance Fund

One of ISA’s key recommendations is that these nations should be compensated if deep-sea mining does commence, which the report predicts will happen in 2027. The requirement for this economic support is linked with the United Nations Convention on the Law of the Sea, which became effective in 1994.

“This support will be in the form of an economic assistance fund created from a portion of the proceeds from deep-sea mining.”

“This support will be in the form of an economic assistance fund created from a portion of the proceeds from deep-sea mining,” said Michael Lodge, ISA secretary-general. Lodge said that the report is based on long-term economic projections and so should be unaffected by the COVID-19 pandemic.

But the proposal already has its critics. Among them is Bramley Murton, who leads the marine mineral research team at the National Oceanography Centre in the United Kingdom. He argues that deep-sea mining will be viable only if the commodity price is high enough as a result of increasing demand. “[Offshore] production costs are always likely to be greater than a well-resourced and efficient on-land mine,” he said.

As the global seabed is not a part of any one nation’s exclusive economic zone, Murton thinks it is unfair that only selected countries should benefit from ocean-mining royalties.

Andy Whitmore of the Deep Sea Mining Campaign is in favor of economic support for developing nations that rely on mining, but he questions the quantity of money that would be available from ISA’s proposed fund. “The amounts that are likely to be paid would likely be very low, unless the scale of deep-sea mining was so widespread, with so many exploitation licenses issued, that there would be significant impact on the seabed in international waters,” he said.

Environmental Threats

Researchers are only beginning to learn how deep-sea mining may affect benthic organisms. For this reason, many organizations are calling for a moratorium on deep-sea mining until environmental impacts are more fully understood. In 2019, the prime minister of Fiji joined these calls with the backing of several other Pacific island nations. The European Parliament adopted a resolution in 2018 urging its member states to stop sponsoring deep-sea mining and to invest in more sustainable consumption of materials.

Sediment plumes are considered the greatest ecological threat posed by deep-sea mining, appearing to cause lasting damage to microbial life. If mining operations scale up, noise could increasingly affect whales and other animals that rely on echolocation, while light pollution could affect animals that use bioluminescence.

“We’re only beginning to scratch the surface of what’s down there. The loss of biodiversity due to mining activities will be inevitable and permanent on a human scale, as nodules take millions of years to form.”

The short- and long-term effects on specific regions are unknown. More than half of the current licenses for deep-sea mining, for instance, relate to the Clarion-Clipperton Zone (CCZ), a fracture region in the Pacific Ocean covering 4.5 million square kilometers, roughly half the size of the continental United States. For the CCZ, the greatest commercial interest is polymetallic nodules, compacted mineral-rich cements resembling blackened cauliflower florets.

Surveys of the CCZ have revealed that it also contains an abundance and diversity of life. Some species, including sponges and anemones, attach themselves to the nodules for feeding. Other species rely on the nodules indirectly, such as the recently discovered octopus nicknamed “Casper” that attaches its eggs to the stalks of dead sponges. A 2016 study published in Scientific Reports suggested that roughly half of the megafauna in the CCZ depend on the nodules as a hard substrate habitat.

“We’re only beginning to scratch the surface of what’s down there. The loss of biodiversity due to mining activities will be inevitable and permanent on a human scale, as nodules take millions of years to form,” said Matthew Gianni, cofounder of the Deep Sea Conservation Coalition.

—James Dacey (@JamesDacey), Science Writer


Dacey, J. (2020), Deep-sea mining may have deep economic, environmental impacts, Eos, 101, https://doi.org/10.1029/2020EO147683. Published on 03 August 2020.

Text © 2020. The authors. CC BY-NC-ND 3.0
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