Companies plan to send machines to the bottom of the oceans to extract rare metals.
Ahead of the resumption on Thursday March 16 of international negotiations on deep-sea mining, a Greenpeace report warns against excessive greed. At the heart of this subject, we find: the famous polymetallic nodules.
These are pebbles, in the shape of a potato, which measure between one and 15 cm in diameter, which lie at a depth of more than 4,000 meters. These nodules (which took hundreds of thousands of years to form) contain rare metals useful for the manufacture of electric batteries. This whets the appetite of private entrepreneurs, such as the Canadian company The Metals Company.
All the metals contained in these nodules are not exploitable
His boss claims to have already spotted in certain areas, enough rare metals to equip a quarter of the world’s car fleet with batteries. He hopes to be able, in the years to come, to suck up these black polymetallic spheres with a kind of underwater combine harvester. But in a report, Greenpeace warns against premature mining, which relies on the work of a German environmental research institute. For the NGO, we must not rely on the deep seabed to find the metals necessary for the energy transition.
Another pitfall: there is no scientific consensus on the quantity of rare metals that it is really possible to find and exploit in the oceans. How many nodules are there, what is their actual composition? All this remains to be clarified. According to this report, even if some reserves are underwater, they far exceed terrestrial reserves.
Not all the metals contained in these nodules can be exploited: lithium, for example, essential for batteries, is not present in sufficient quantity. Only the extraction of cobalt, nickel, copper and manganese would eventually be possible. But the environmental impact of such exploitation, with the noise of the machines, and the clouds of sediment, is not known. In this context, it is important to continue to rely on terrestrial resources, the sobriety and the recycling of existing metals, insists the NGO, which supports the idea of a moratorium of several years on mining. The time to better know scientifically the state and the real potential of the marine environment.
Even in 2023, we still know very little about the ocean at more than 4,000 meters deep. Although these deep oceans cover two-thirds of the planet, we know very little about them: 95% of their surface remains to be explored. Another very evocative figure: today there are 250,000 living underwater species. But there are likely 40 times more to discover, according to studies from theFrench Research Institute for the Exploitation of the Sea (Ifremer). Figures impossible to hide in this debate.