When Climate and Biodiversity Collide: Deep Seabed Mining

By Qaisarah and Jolyn, mentored by Marius Toime

About 5km deep at the bottom of the Pacific Ocean lies the Clarion-Clipperton Zone (“CCZ”).^[1] It is a real-life Bikini Bottom of sorts, but far stranger than fiction. A westward sloping seafloor with scattered hills and seamounts,^[2] the CCZ is a region rich in biodiversity. 90% of the species it houses are new to science. The ecosystem is supported by stalked glass sponges attached to polymetallic nodules (“PMNs”),^[3] which are small mineral rocks the size of potatoes that rest on the ocean floor.^[4]

Deep seabed mining (“DSM”) is a form of resource extraction,^[5] where metals such as cobalt, copper, nickel, manganese and gold are mined from PMNs, hydrothermal vents, and seamount crusts.^[6] The allure of DSM is its staggering mineral wealth. For instance, the total cobalt within PMN deposits in the CCZ is 44,000 kilotons, which is more than five times the global terrestrial reserves. As geopolitics undeniably drives States’ appetite for DSM, a conditional moratorium which draws insights from past multilateral treaties is crucial to prevent an unregulated scramble to harvest these deep-sea PMNs.^[7]

The main legal architecture regulating DSM is Part XI of the 1982 United Nations Convention on the Law of the Sea (“UNCLOS”).^[8] UNCLOS designates the seabed beyond national borders as "the Area,"^[9] to be managed exclusively by the International Seabed Authority (“ISA”).^[10] To this end, the ISA continues to formulate the Mining Code, which prescribes rules and procedures consistent with UNCLOS.^[11] UNCLOS declared the Area and its resources the “common heritage of mankind” (“CHM”)^[12]—an ideal that is buckling under geopolitical pressure today.

However, international law is not immune to power politics. As critical legal scholars observe, international law fails to establish an objective, non-political realm because it oscillates endlessly between concrete State practice and normative utopian aspirations.^[13] When the two collide, the legal framework is malleable to political power. Western free-market interests exemplified this in 1994 by forcing a complete overhaul of Part XI via the 1994 Implementation Agreement before ratifying the treaty.^[14]

Politics continues to shape DSM both within and outside the legal framework today to serve subjective state and corporate interests under the guise of legal rights. As critical minerals become vital for the green energy transition^[15] and national defense,^[16] China and the United States (“US”) are wielding legal frameworks as instruments of statecraft in a fierce resource race.

China has masterfully wielded the international machinery by adopting[1]  UNCLOS norms to project legitimacy while prioritizing commercial and industrial readiness. For instance, China holds five of the 30 exploration contracts issued by the ISA, which is the most any country holds.^[17] It has dutifully mirrored UNCLOS text in its domestic laws to signal formal compliance.^[18] Once a champion of the CHM principle and the voice of developing nations, China now leverages its institutional weight within international negotiations to protect its commercial interests.^[19] For example, in July 2023, when conservation-minded states attempted to formally debate a precautionary pause on seabed mining, China and its allies froze the agenda.^[20] Furthermore, citing scientific uncertainty and data gaps, China advocated for further study on internalizing environmental costs rather than embedding these financial mechanisms directly into a single binding provision of the Mining Code.^[21] Taken together, China’s political motivations and operation within UNCLOS actively transform DSM governance, steering international rulemaking toward a more permissive regime.

Meanwhile, as a non-party to UNCLOS,^[22] the US has unilaterally acted outside the regime. In April 2025, the US issued Executive Order 14285, which domestically authorized DSM in international waters.^[23] The US is of the view that their legal basis for DSM in the Area lies in its own domestic legislation, the 1980 Deep Seabed Hard Mineral Resources Act.^[24] However, by allowing mining companies to apply for licenses through the US government instead of the ISA, the US tests the boundaries of customary international law obligations, particularly the duty of due regard for the collective interests of the international community.^[25] Such norm-breaking risks dangerous regulatory fragmentation.^[26] Upon realizing their competitive disadvantage, other States may follow suit to evade international environmental safeguards. This could take the form of acting unilaterally as non-parties, funneling sponsored contractors through “back-door” applications under the US framework, or diluting their own commitment to the ISA. Ultimately, such behavior would weaken the common good of sustainable resource management.^[27]

This fragmented legal landscape and the geopolitical tug-of-war over the seabed reflect a broader crisis between climate mitigation and biodiversity preservation. These are two battles that humanity cannot afford to lose, and they are on a direct collision course at the bottom of the Pacific.

At the center of this clash lies a striking irony. The treaties designed to save the planet have become a rallying cry for DSM advocates. Citing the Paris Agreement, they argue that critical mineral shortages threaten to stall the clean energy transition,^[28] noting that producing an electric vehicle (“EV”) requires six times the mineral input of a gas-powered equivalent, driving projected demand for clean-energy metals up thirty-fold by 2040.^[29] Faced with these looming deficits, proponents turn to the ocean floor, where polymetallic nodules consolidate essential battery metals including cobalt, nickel, copper, and manganese within one “rock.”^[30] Driven by this sheer yield density, advocates position seabed extraction as necessary. While traditional land-based mining must crush 64 metric tons of ore to yield those key metals, marine nodules deliver the exact same output from just six.^[31] 

Beyond material efficiency, advocates frame seabed extraction as a geopolitical necessity, highlighting that over 70% of global cobalt originates from a single country, The Democratic Republic of the Congo,^[32] leaving green supply chains dangerously concentrated. The seabed thus presents a lucrative alternative, with major economic models projecting internal rates of return for deep-sea operations between 17% and 27%, outperforming the 12% average of terrestrial mining.^[33] Recently, successful sea trials by Japan have demonstrated full-system collection from depths of 6,000 meters, pushing the industry to the brink of commercial application.^[34]

However, framing DSM as a clean-tech savior relies on a dangerous, out-of-sight, out-of-mind calculus that overlooks economic, ecological and governance realities. Economically, deep-sea metals are far from indispensable as EV technology shifts toward cobalt- and nickel-free battery chemistries, like Lithium Iron Phosphate and sodium-ion, alongside expanding recycling networks.^[35] Ecologically, achieving "No Net Loss" of biodiversity is unviable in the deep sea, where critical baseline knowledge gaps, multi-century recovery timescales, and unproven restoration techniques render ecological losses effectively permanent,^[36] as demonstrated by research showing how benthic communities fail to fully recover even 26 years after a disturbance.^[37] These physical and biological barriers are compounded by governance constraints within the ISA such as the heavy reliance on state self-reporting.^[38] This regulatory vulnerability peaked when Nauru invoked Section 1, Paragraph 15 of the 1994 Implementation Agreement, known as the Two-Year Rule, forcing the ISA Council to consider commercial applications without a finalized Mining Code.^[39]

Acknowledging these failures does not necessitate an absolute permanent ban.  Outright prohibitions risk unintended regulatory leakage, shifting extraction into national Exclusive Economic Zones with weaker environmental oversight,^[40] fostering black-market mineral emergence or intensifying pressure on harmful terrestrial mines.^[41] ​​Instead, a conditional moratorium delivers precautionary environmental protection within the UNCLOS legal framework. Anchored in Article 145, which mandates the effective protection of the marine environment from harmful effects, and the precautionary principle, a temporary pause legally freezes commercial operations.^[42] This preserves the CHM principle while allowing time to establish strong, science-based rules, robust oversight, and verifiable safeguards under the neutral leadership of Secretary-General Leticia Carvalho.^[43]

To escape the binary choice between immediate exploitation and a permanent ban, the ISA should establish a conditional moratorium modeled on the Convention on the Conservation of Antarctic Marine Living Resources (“CCAMLR”) rather than the 1986 International Whaling Commission moratorium, which devolved into a de facto ban,^[44] while being subverted by lethal harvesting programs under the legal guise of “scientific research”.^[45] By contrast, the CCAMLR prevents the development of any fishery from outpacing the institution’s capacity to evaluate its ecological consequences.^[46] For instance, activities must begin with a tightly regulated exploratory phase, where catch limits are severely restricted and harvesting is explicitly tied to mandatory scientific data collection mandated by the Scientific Committee.^[47] Full commercial extraction is then only evaluated once sufficient empirical baselines are established.^[48] 

Lifting commercial restrictions under this framework must thus target specific, predefined scientific criteria. Scientifically, requiring a full-species taxonomic catalog before approving operations is practically unachievable and functions as a permanent ban by default, given that 88% to 92% of benthic species in the CCZ remain undescribed.^[49] Since biological restoration takes a very long time, lifting criteria cannot depend on ecosystem recovery so instead, the ISA must evaluate biogeography, population connectivity, and biodiversity hotspots to establish strict spatial preservation targets.^[50] In practice, this requires mandating undisturbed zones across the CCZ that are fully buffered from mining machinery and drifting sediment plumes.^[51] Simultaneously, regulators ought to move beyond artificial acute toxicity metrics by incorporating weight-of-evidence frameworks to monitor heavy-metal plume stress^[52] while setting strict acoustic noise thresholds. Administratively, replacing contractor self-reporting with independent 24/7 scientific monitoring eliminates conflicts of interest and ensures regulatory integrity.^[53]

Ultimately, a conditional moratorium is not an admission of institutional failure, but a test of governance maturity for the global commons. By establishing clear, empirical thresholds, this approach transforms deep-sea mining from a false dichotomy between climate action and ocean conservation into a synchronized effort. A structured pause buys essential time to ensure the CHM principle is guided by scientific evidence rather than commercial momentum and geopolitical friction.

References

^[1] Tanja Stratmann et al, “Polymetallic Nodules are Essential for Food-Web Integrity of a Prospective Deep-Seabed Mining Area in Pacific Abyssal Plains” (2021) 11 Sci Rep 12238 at pp 1, 7.

^[2] Si-Yuan Sean Chen et al, “Oceanic Bottom Mixed Layer in the Clarion-Clipperton Zone: Potential Influence on Deep-Seabed Mining Plume Dispersal” (2023) 23 Env Fluid Mech 579 at 580.

^[3] “Deep Ocean Targeted for Mining is Rich in Unknown Life”, The Straits Times (25 July 2023) <https://www.straitstimes.com/world/deep-ocean-targeted-for-mining-is-rich-in-unknown-life> (accessed 9 August 2026).

^[4] Melissa J Betters, “What Are Polymetallic Nodules?”, Smithsonian Ocean <https://ocean.si.edu/planet-ocean/seafloor/what-are-polymetallic-nodules> (accessed 9 August 2026).

^[5] Hao Shen, “Legal Regime for Internalizing the Environmental Costs in Deep Seabed Mining: Policy Considerations and Future Development” (2025) 53(6) Coastal Management 412 at 412.

^[6] Catherine Coumans, “Is Everything New Old Again? Deep Seabed Mining’s Unprecedented Ecosystem Risks Are Exacerbated by Environmental and Governance Practices Imported from Terrestrial Mining” (2026) 27 Extractive Industries and Society 101950 at pp 1–2.

^[7] JR Hein et al, “Deep-ocean mineral deposits as a source of critical metals for high- and green-technology applications: Comparison with land-based resources” (2013) 51 Ore Geol Rev 1, cited in Alexander Cunningham, “Assessing the Feasibility of Deep-Seabed Mining of Polymetallic Nodules in the Area of Seabed and Ocean Floor Beyond the Limits of National Jurisdiction, as a Method of Alleviating Supply-Side Issues for Cobalt to US Markets” (2024) 37 Miner Econ 207 at 209.

^[8] Hao Shen, “Developing China’s Legal Regime for International Deep Seabed Mining—The Present and Future” (2021) 52(1) Ocean Dev Int Law 20 at 21.

^[9] United Nations Convention on the Law of the Sea (10 December 1982), 1833 UNTS 397, Art 1(1) (entered into force 16 November 1994).

^[10] UNCLOS Art 137(2).

^[11] Xiangxin Xu & Li Chen, “Navigating a New Course: The Likely Impact of the BBNJ Agreement on the Establishment of Area-Based Management Tools by the ISA” (2025) 40 Int J Mar Coast Law 328 at p 330 n 7.

^[12] UNCLOS Art 136.

^[13] Martti Koskenniemi, From Apology to Utopia: The Structure of International Legal Argument (Cambridge University Press, 2006) at pp 17, 66.

^[14] Robin R Churchill, “The 1982 United Nations Convention on the Law of the Sea” in The Oxford Handbook of the Law of the Sea (Donald R Rothwell et al eds) (Oxford University Press, 2015) ch 2 at p 25.

^[15] Alves Dias P et al, Cobalt: demand-supply balances in the transition to electric mobility (Publications Office of the European Union, 2018) and Z Chen et al, “Tracking and quantifying the cobalt flows in mainland China during 1994–2016: Insights into use, trade and prospective demand” (2019) 672 Sci Total Environ 752, cited in Cunningham at p 218.

^[16] E Hache, Geopolitics of the Abyss: Power, Metals and Global Fractures (IRIS, 2025) and LL Tupuana'i & SE Raymond, “Financialization, indigenous resistance and the case of deep seabed mining in American Samoa” (2026) 27 The Extract. Indus. and Soc 101874, cited in Coumans at p 1.

^[17] J Trainer, “The Geopolitics of Deep-Sea Mining and Green Technologies” (2022) Center for a New American Security <https://www.cnas.org/publications/commentary/the-geopolitics-of-deep-sea-mining-and-green-technologies>, cited in Sandra Cassotta & Michael Goodsite, “Deep-Seabed Mining: An Environmental Concern and a Holistic Social Environmental Justice Issue” (2024) 2 Front Ocean Sustain 1355965 at p 13.

^[18] Shen, “Developing China’s Legal Regime” at p 30.

^[19] Nengye Liu & Shirley V Scott, “China in the UNCLOS and BBNJ Negotiations, Yesterday Once More?” (2025) 38 Leiden J Int'l L 168 at pp 172–173, 175, and 183.

^[20] Pradeep A Singh, Aline Jaeckel & Jeff A Ardron, “A Pause or Moratorium for Deep Seabed Mining in the Area? The Legal Basis, Potential Pathways, and Possible Policy Implications” (2025) 56(1) Ocean Dev & Int'l L 18 at p 33; Cassotta & Goodsite at p 8.

^[21] Shen, “Legal Regime for Internalizing the Environmental Costs” at p 413.

^[22] Haoyang Luo, Guanding Wang & Liang Yu, “Constraining US Unilateral Deep Seabed Mining: Cooperative Obligations of Non-Party States” (2026) 13 Front Mar Sci 1859648 at p 2.

^[23] Luo, Wang & Yu at p 1.

^[24] Luo, Wang & Yu at p 2; Deep Seabed Hard Mineral Resources Act, Pub L No 96-283, 94 Stat 553 (1980).

^[25] Luo, Wang & Yu at p 4.

^[26]  Luo, Wang & Yu at p 2.

^[27] Luo, Wang & Yu at p 2.

^[28] Chang Wang et al, “Deep-Sea Mining: A Potential Solution to Secure Critical Energy Minerals Availability” (2025) 4 npj Ocean Sustain 59 at para 2.

^[29] Afrah A Qoqandi, “The Case for a Moratorium on Deep-Sea Mining: The International Seabed Authority, Indigenous Rights, and Marine Ecosystems in the Eastern Pacific” (2026) 32 Hastings Envt'l LJ 37 at 42.

^[30] Qoqandi at 41.

^[31] Qoqandi at 41.

^[32] Wang at para 6.

^[33] Wang at para 9.

^[34] “Japan Deep-Sea Hunt Finds Rare Earths as It Seeks to Cut Reliance on China”, Al Jazeera (2 February 2026) <https://www.aljazeera.com/news/2026/2/2/japan-deep-sea-hunt-finds-rare-earths-as-it-seeks-to-cut-reliance-on-china> (accessed 12 August 2026) at para 2.

^[35] European Academies’ Science Advisory Council, Deep-Sea Mining... (EASAC, June 2023) <https://easac.eu/fileadmin/user_upload/EASAC_Deep_Sea_Mining_Web_publication_.pdf> (accessed 12 August 2026) at 6–7.

^[36] Holly J Niner et al, “Deep-Sea Mining With No Net Loss of Biodiversity—An Impossible Aim’ (2018) 5 Front Mar Sci 53 at 3.

^[37] Daniel O B Jones et al, “Biological Responses to Disturbance from Simulated Deep-Sea Polymetallic Nodule Mining” (2017) 12(2) PLOS ONE e0171750 at 17.

^[38] Neil Craik et al, “The International Seabed Authority, the Problem of Disregard and the Case for Administrative Accountability” (2025) 74(S1) ICLQ 267 at pp 271–283.

^[39] Pradeep A Singh, “The Invocation of the 'Two-Year Rule' at the International Seabed Authority: Legal Consequences and Implications” (2022) 37 Int J Mar Coast Law 375 at 385–387, 393.

^[40] Pradeep A Singh, Aline Jaeckel & Jeff A Ardron, “A Pause or Moratorium for Deep Seabed Mining in the Area? The Legal Basis, Potential Pathways, and Possible Policy Implications” (2025) 56(1) Ocean Dev & Int'l L 18 at 42.

^[41]  Qoqandi at 53.

^[42] Singh, Jaeckel & Ardron at 29–31.

^[43] Wang at para 6.

^[44] Cameron Jefferies & Kate Latos, “The International Moratorium on Commercial Whaling: A Brief History and Socio-Legal Assessment” in Nikolas Sellheim & Joji Morishita eds, Japan's Withdrawal from International Whaling Regulation (Brill, 2025) ch 7 at 140.

^[45] Whaling in the Antarctic (Australia v Japan: New Zealand intervening) (Judgment) [2014] ICJ Rep 226 at paras 230–231.

^[46] Andrew J Constable et al, "Managing Fisheries to Conserve the Antarctic Marine Ecosystem: Practical Implementation of the Convention on the Conservation of Antarctic Marine Living Resources (CCAMLR)" (2000) 57 ICES J Mar Sci 778, <https://doi.org/10.1006/jmsc.2000.0725> at 785.

^[47] Constable et al at 786.

^[48] Constable et al at 786.

^[49] Muriel Rabone et al, “How Many Metazoan Species Live in the World's Largest Mineral Exploration Region?” (2023) 33(12) Curr Biol 2383 at 2386.

^[50] Craig R Smith et al, “Editorial: Biodiversity, Connectivity and Ecosystem Function Across the Clarion-Clipperton Zone: A Regional Synthesis for an Area Targeted for Nodule Mining” (2021) 8 Front Mar Sci 797516 at 2–3.

^[51] Smith et al at 2–3.

^[52] Rob Williams et al, “Noise from Deep-Sea Mining May Span Vast Ocean Areas” (2022) 377 Science 157 at 158.

^[53] J A Ardron, H A Ruhl & D O B Jones, “Incorporating Transparency into the Governance of Deep-Seabed Mining in the Area Beyond National Jurisdiction” (2018) 89 Mar Pol 58 at 64–65.