By Emily Vidovich. Emily has a background in environmental journalism and sustainability and is a member of the George Washington University Class of 2019.

A report from the World Bank estimates that 3 billion tons of metals and minerals will be needed to create the renewable energy infrastructure necessary to keep global warming below 2°Celsius, raising concern about sourcing the necessary materials. On the ocean floor, rocks called polymetallic nodules contain the metals needed to create the batteries that power electric vehicles, providing an alternative to land-based metal extraction.

The Metals Company is at the forefront of exploration for and mining of these nodules in the deep sea. Based on field studies, the company estimates that one of their designated undersea exploration areas alone would be able to provide metals for 140 million electric vehicle batteries. Additionally, the company estimates that within their three exploration areas, there are enough polymetallic nodules to “electrify a quarter of the world’s passenger vehicle fleet (approximately 280 million EVs).”

The company visualizes a future in which the reuse and recycling of all metals in circulation means extraction from earth is no longer needed. In order for that to happen, there first needs to be enough harvested metals to support a global population driven by technology and renewable energy. Doctor Gregory Stone, the company’s chief ocean scientist who spent most of his career working in environmental conservation, says that The Metals Company’s sole focus is harvesting nodules from the seafloor because they view it as the least impactful way to source the amount of metal humanity requires.

Polymetallic nodules resting on the ocean floor in the deep sea. Credit: The Metals Company

According to Forbes, deepsea mining is a better alternative to land-based mining from both environmental and social perspectives. The refinement of nodules does not create soil and water contamination or toxic runoff, unlike its land-based counterpart. Additionally, deepsea mining results in much less habitat loss—deforestation is part and parcel with metal mining on land—and seems to eschew the exploitative labor practices found in land-based mining. Nodule mining is also less impactful than other forms of deepsea mining, since nodules are not attached to the ocean floor and do not require breaking the earth’s crust in order to be collected.

Deepsea mining is much less carbon-intensive than the land-based alternative as well. A paper in the Journal of Cleaner Production found that deepsea mining of nodules reduces the emissions from obtaining metals by up to 80 percent, and puts 94 percent less sequestered carbon at risk of re-release into the atmosphere compared to land-based mining. The study also calculated that making 1 billion electric vehicle batteries from nodules would reduce atmospheric carbon dioxide by 11.5 gigatonnes. 

However, deepsea mining is not an infallible process. Because it is such a new industry, scientists warn that we do not yet understand the full extent of its ramifications on deepsea ecosystems, or the ocean as a whole.

One concern is that sediment clouds created underwater when the seafloor is disturbed could be carried by currents and affect organisms in other parts of the ocean. Researchers at the Scripps Institute of Oceanography and the University of California San Diego that study plume movement found that underwater turbulence quickly dilutes sediment levels. However, more data is needed to comprehensively understand plume behavior.

Additionally, since sediment accumulates on the ocean floor at an average rate of several centimeters every thousand years, it could take the habitat a long time to recover from the collection processeven if only a few centimeters of seafloor are disturbed. Stone points out that the area of the abyssal plain that The Metals Company is exploring has some of the lowest biomass on the planet—an estimated 3,000 times less biomass than the rainforests where much land-based mining occurs. However, the impacts of habitat disturbance and sediment plumes on deepsea organisms are still unknown.

Stone says a cost-benefit analysis of any activity must consider how the entire planetary system is affected. If the deepsea mining of nodules is not utilized, the increasing demand for metals will inevitably lead to further expansion of land-based mining and its coupled deforestation, water contamination, and human rights infringements. Therefore, if supplanting mining on land with mining in the sea has less negative impacts while providing the materials humanity requires more efficiently, utilizing deepsea mining could prove to be the most sustainable path forward.

 

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