A recent study has detailed the ecological impact of deep-sea mining test operations, reporting reductions in seabed animal populations and species diversity in affected areas.
These findings emerge as international negotiations continue to establish regulations for deep-sea mining in international waters, while the United States pursues an independent approach to developing its deep-sea mineral industry.
Overview of Deep-Sea Mining
Deep-sea mining involves extracting polymetallic nodules found on the ocean floor, often at depths exceeding 10,000 feet. These nodules contain metals such as nickel, cobalt, manganese, and copper, which are identified as critical minerals for green technologies like solar panels, wind turbines, and electric vehicles, essential for addressing climate change. The International Energy Agency forecasts a potential doubling of demand for these minerals by 2040.
The Clarion-Clipperton Zone in the Pacific Ocean, spanning 6 million square kilometers, is estimated to contain over 21 billion tonnes of these polymetallic nodules. The Metals Company, a prominent mining firm, seeks to be among the first to commercially harvest these minerals at a large scale. They plan to use a large vacuum-like device to collect nodules from the seabed and transfer them to a surface vessel.
Ecological Impact Study Reveals Significant Harm
A recent study assessed the ecological impact of deep-sea mining machinery on seabed environments. Conducted by scientists from the Natural History Museum in London, the UK National Oceanography Centre, and the University of Gothenburg, the research was initiated at the request of The Metals Company. The researchers affirmed their independence, stating the company had access to results prior to publication but no authority to modify them.
The team compared biodiversity data collected two years before and two months after test mining activities. During these tests, machines traversed 80 kilometers of the seafloor, removing approximately the top five centimeters of sediment, which constitutes the primary habitat for many deep-sea animals. The investigation focused on macrofauna, animals ranging from 0.3mm to 2cm in size, including worms, sea spiders, snails, and clams.
Findings indicated a 37% decrease in the number of animals and a 32% reduction in species diversity within the vehicle tracks.
In areas adjacent to the vehicle tracks where sediment clouds settled, no decrease in animal abundance was observed, though a shift in dominant species occurred. A spokesperson for The Metals Company acknowledged the data, noting that the observed biodiversity impacts were confined to the directly mined areas. One expert commented that the study's findings suggest current harvesting technologies may be too damaging for large-scale commercial exploitation, given the measurable impact observed in tests.
Broader Environmental Concerns and Ecosystem Impacts
Scientists express multiple considerations regarding the potential environmental impact of deep-sea mining:
- Habitat Disturbance: Polymetallic nodules are habitats for deep-sea ecosystems. Their removal disturbs the silty seabed and affects organisms such that approximately 20-30% of deep-sea life depends on nodules for attachment and survival. The Metals Company plans to leave approximately 5% of nodules behind.
- Undiscovered Species: The deep ocean remains largely unexplored. The study identified over 4,000 animal species in the remote Pacific Ocean region under investigation, with 90% previously unrecorded. There is a significant risk of affecting undiscovered lifeforms.
- Pollution and Recovery: Pollution from mining operations could affect less resilient species, and questions have been raised about the potential for animal populations to recover post-disturbance.
- Sediment Plumes: The mining process generates sediment plumes when processed material is released back into the ocean. Early studies indicated this could impact the larger food web by interfering with filter-feeding marine life and potentially affecting larger species like tuna, whales, and turtles. The Metals Company now plans to release sediment plumes at greater depths (around 6,000 feet) to mitigate this impact.
- Planetary Regulation: The deep ocean environment is critical for planetary regulation and is already susceptible to rising temperatures.
Global Governance vs. U.S. Independent Path
International negotiations are currently underway in Jamaica to establish rules for deep-sea mining. These discussions are overseen by the International Seabed Authority (ISA), an organization created under a United Nations treaty, which is responsible for developing regulations for international waters. Deep-sea mining in international waters is currently not permitted pending further assessment of its environmental consequences. The ISA also protects some areas from mining.
The United States has not ratified the United Nations Convention on the Law of the Sea (UNCLOS), which established the ISA. Instead, the U.S. is independently advancing its deep-sea mining industry.
In 2022, an executive order was signed to develop seabed mining. Subsequently, the National Oceanic and Atmospheric Administration (NOAA) has accelerated the environmental review process for such projects. This new process allows companies to apply for exploration and commercial mining permits simultaneously, consolidating previous two-step environmental reviews into one. NOAA stated that this process aims to help mining companies more efficiently obtain permits, facilitating a supply of rare earth minerals for the U.S.
Conservation groups argue that this expedited process reduces opportunities for analysis and public input. Concerns have also been raised by local leaders in American Samoa and Guam regarding the potential for mining in surrounding U.S. territories without sufficient consultation. Critics suggest that the U.S. operating outside the international framework could affect its reliance on international cooperation for other customary ocean laws, such as those governing shipping and fishing.
Industry Prospects and Timelines
The Metals Company has applied with U.S. regulators for a 20-year lease to extract over a million tons of nodules, focusing on the Clarion-Clipperton Zone in the Pacific Ocean. The company is currently drafting environmental impact reports and aims to begin commercial deep-sea mining by 2024.