What’s best for Earth? The debate over deep ocean mining

Introduction: A Summit and a Contested Frontier

The episode opens by framing deep-sea mining as one of the deepest ecological and geopolitical battlegrounds of our time. With the UN’s International Seabed Authority (ISA) developing regulations for international waters, proponents and opponents clash over whether the deep sea should be opened to mining. The narrative notes a 2024/2025 push from some actors, including the U.S. administration, to accelerate access to deep-sea metals, even as regulators stress caution and the need for a robust safety blueprint. The backdrop is the CCZ, an enormous international-water region rich in polymetallic nodules that could supply cobalt, nickel, copper, and rare earth elements (REEs) for batteries, electronics, and aerospace. A key political thread is the tension between green transition goals and the ecological costs of mining on the ocean floor.

Science of Nodules: Formation, Habitat, and Non-Renewability

Scientists describe two main pathways by which nodules form. First, adsorption of metals from the water column coats minerals on sinking particles, like shark teeth, with manganese oxides and iron oxyhydroxides. Second, diffusion—driven by microbial degradation of organic matter that settles to the seafloor—releases metals that subsequently oxidize and precipitate as oxyhydroxides, incorporating into nodules. The Clarion Clipperton Zone is portrayed as ancient and pristine, with nodules growing extremely slowly, at tens of millimeters per million years, marking them as non-renewable on human timescales. These nodules also provide essential habitat for sessile organisms and a community of mobile species, making the potential ecological impact of mining substantial and lasting.

Economics and Geopolitics: The Metals Race and Global Power

The conversation shifts to the economic logic underlying deep-sea mining. The argument is that the batteries powering electric vehicles and other green technologies rely on metals like cobalt, nickel, copper, and REEs that nodules contain. Proponents say that deep-sea sources could diversify supply away from land-based mines—especially given the historical concentration of REEs in a few regions or countries, notably China, with environmental concerns attached to mining and processing. Gerard Barron of The Metals Company contends nodules are as accessible as golf balls on a driving range, implying a relatively scalable extraction compared to terrestrial mining. He argues this could shift geopolitical dynamics by reducing the control of any single country over critical minerals. A contrasting view from Walter Sogness of Glomar Minerals frames the deep sea as a cautious but potentially necessary stopgap in the transition away from hydrocarbons, while acknowledging the political stakes of resource control.

Regulatory Landscape and Environmental Testing: Can We Do This Safely?

The episode highlights the International Seabed Authority’s ongoing efforts to regulate deep-sea mining and notes growing calls for a moratorium from 38 countries until scientists can determine the safest approaches. Environmental science from the European GPI Oceans Project, led by Matthias Heckel, shows that test-disturbances in the CCZ and Peru Basin decades ago left sediments with little recovery, underscoring the fragility of deep-sea ecosystems. The process of dredging or suction mining disturbs the top centimeters of sediment and can generate plumes that spread across habitats, potentially affecting everything from specialized bacteria to larger organisms up the food chain. The researchers emphasize that once disrupted, these communities may not return within any meaningful human timeframe, tightening the case for precaution and rigorous regulatory standards.

Questions of Balance: Green Transitions, Recycling, and the Path Forward

Discussion turns to the broader energy transition, noting that while deep-sea sources could ease supply concerns for EVs and wind turbines, the environmental costs, regulatory gaps, and long recovery times demand careful consideration. The conversation points to alternative technologies such as sodium-ion batteries and increased recycling as ways to reduce reliance on newly mined REEs. The geopolitical argument expands to concerns about the distribution of mineral resources and the influence of major players on supply chains. The speakers acknowledge that there is no simple answer, and the right balance may involve moratoriums, safer mining technologies, stronger environmental safeguards, and investment in a more circular economy for metals.

Key Takeaways and Quotes

"The deep sea cannot become the wild west." - Antonio Guterres, UN Secretary-General

"They literally sit there like golf balls on a driving range." - Gerard Barron, The Metals Company

"The nodules down there grow super slowly at an average rate of tens of millimeters per million years." - Emily Kwong

"There is a reason why all countries and all nations, they have a critical mineral strategy." - Walter Sogness