Calls for a global moratorium on deep-sea mining have gotten louder as the results of a five-year-long investigation have been revealed.
Scientists have analysed samples from the seafloor in the depths of the Pacific, both before and after an 80km area was driven over by ocean-mining machines.
Researchers from the University of Gothenburg, the UK’s Natural History Museum and National Oceanography Centre spent more than 160 days at sea, followed by three years in the lab to discover the extent of damage caused by the tracks.
The study, which has been published in science journal Nature, was funded by The Metal Company, a deep-sea mining giant aiming to become the first to conduct commercial mining on the ocean floor.
Scientists say their findings have been carried out independently, and that the company was able to view the results before publication but was not allowed to alter them.
Deep-sea mining’s impact on biodiversity
Researchers examined data from the Clarion-Clipperton Zone, located between Hawaii and Mexico, that is currently being targeted due to itsmineral-rich seabed.
They found more than 4,000 animals living on the seafloor and tracked the area’s biodiversity two years before and two months after the mining machine recovered more than 3,000 tonnes of polymetallic nodules.
They warned that the number of macrofaunal animals found in the tracks of the mining vehicles was reduced by a staggering 37 per cent compared to untouched areas. These are organisms visible to the naked eye, such as worms, crustaceans, snails and clams.
There was no impact on animal abundance in regions covered by sediment plume from the machine. However, the team did find that the test caused a 32 per cent reduction in species richness (the number of different species in a particular area).
The Metals Company says they are “encouraged” by the findings, arguing that biodiversity impacts are “limited to the directly mined area”.
However, environmental organisation Greenpeace argued the test used a machine “half the size of those intended to be used”, which means the real impact of deep-sea mining would be much greater.
Georgia Whitaker of Greenpeace International says: “The Metals Company is trying to spin attention away from the headline bad news but we’re talking about harming unique and precious newly-discovered marine creatures.
“It’s misleading for them to claim that only the mining site itself would be affected.”
Why do countries want to conduct deep-sea mining?
The growing appetite for deep-sea mining revolves around small rocks found on the seafloor, which are loaded with critical minerals such as copper, iron, zinc and more.
These minerals can be used to build green technology such as batteries for electric vehicles (EVs), solar panels and mobile phones. While such minerals can also be found on land, mining them often comes with risky supply chains and unethical practices, as exposed in multiple investigations.
However, a report published last year by the Environmental Justice Foundation found deep-sea mining is not actually necessary for the clean energy transition.
It argues that a combination of advanced technology, a circular economy and recycling could together slash demand for minerals by 58 per cent between 2022 and 2050.
Along with now-proven concerns that deep-sea mining damages biodiversity, experts also warn that the practice risks impacting carbon stored in the ocean.
Which countries are exploring deep-sea mining?
Last year, Norway became the first country in the world to greenlight deep-sea mining practices – allowing the country to eventually open up 280,000 square metres of national waters.
It had planned to start issuing licenses for mining in 2025, but last week Norway’s newly elected government announced this will be delayed for at least four years as part of negotiations to get its 2026 State budget across the line.
While the move was hailed by environmentalists from groups such as Greenpeace and WWF, Prime Minister Jonas Gahr Støre told reporters that it should be understood as a postponement rather than a permanent ban.
He added that the Socialist Left Party, which obstructed budget agreements on 3 December, does not “hold power forever” but confirmed that seabed mining will not take place during the current parliamentary period which doesn’t end until 2029.
Last month, Cook islands authorities also pushed back deep-sea mining applications in the Pacific nation’s water, delaying mining in the region until at least 2032.
Back in April, Donald Trump signed an executive order aimed at stepping up deep-sea mining within both US and international waters as his country races to become what it describes as a “global leader in responsible seabed mineral exploitation”.
The move was met with heavy criticism from the likes of China, who have delayed issuing permits until countries agree to a framework for how resources could be shared.
At the same time, support for a temporary ban on the practice has also gained momentum. This has been backed by more than 35 countries and the EU.