Environmental impacts of deep sea mining: a comprehensive review of regulatory frameworks and ecological risks

Authors: Ashby, A

Open access courtesy of:

DOI https://doi.org/10.36487/ACG_repo/2615_159

Cite As:
Ashby, A 2026, 'Environmental impacts of deep sea mining: a comprehensive review of regulatory frameworks and ecological risks', in AB Fourie, G Boggs, J Heyes & M Tibbett (eds), Mine Closure 2026: Proceedings of the 19th International Conference on Mine Closure, Australian Centre for Geomechanics, Perth, pp. 1-18, https://doi.org/10.36487/ACG_repo/2615_159

Download citation as:   ris   bibtex   endnote   text   Zotero


Abstract:
Deep sea mining (DSM) is an emerging frontier in global resource development, driven by demand for critical minerals needed for the energy transition. The International Seabed Authority (ISA) has issued 31 exploration contracts covering more than 1.3 million km² of sea floor; however, exploitation regulations remain unresolved and the governance capacity of contracted states is a growing concern. This rapid review evaluates key environmental impact pathways, including habitat destruction, biodiversity loss, sediment plume generation, disruption of oceanic carbon sequestration, impacts on pelagic ecosystems and fisheries-dependent communities and long-term ecosystem alteration. Evidence synthesised indicates DSM poses substantial and potentially irreversible risks to marine ecosystems, with recovery timescales potentially extending from centuries to millennia. Restoration is scientifically unproven and economically prohibitive, with the only peer-reviewed deep sea restoration cost estimate reaching up to USD75 million per hectare. Post-impact restoration cannot be treated as a credible mitigation or offset mechanism. Many states holding exploration contracts exhibit limited regulatory capacity, weak treaty compliance and elevated institutional risk. The findings underscore the urgent need for precautionary governance frameworks, strengthened environmental baseline monitoring and enhanced international oversight before commercial-scale DSM is authorised.

References:
Alam, L, Pradhoshini, KP, Flint, RA & Sumaila, UR 2025, ‘Deep-sea mining and its risks for social-ecological systems: Insights from simulation-based analyses’, PLOS ONE, vol. 20, no. 3.
Alaska Beacon 2026, Interior Department seeks industry interest in seafloor mining off Alaska, viewed 22 June 2026,
Alger, J, Green, JF, Neville, KJ, Park, S, VanDeveer, SD & Webster, DG 2025, ‘The false promise of deep-sea mining’, npj Ocean Sustainability, vol. 4, no. 1, p. 21.
Andrade, D 2024, ‘The mysteries of the abyss: understanding ecosystem dynamics in deep-sea habitats,’ Journal of Marine Science: Research and Development, vol. 14, no. 473.
Amon, DJ, Levin, LA, Metaxas, A, Mudd, GM & Smith, CR 2022, ‘Heading to the deep end without knowing how to swim: Do we need deep-seabed mining?’, One Earth, vol. 5, no. 3, pp. 220–230.
Amon, DJ, Ziegler, AF, Dahlgren, TG, Glover, AG, Goineau, A, Gooday, AJ, … Smith, CR 2016, ‘Insights into the abundance and diversity of abyssal megafauna in the eastern Clarion–Clipperton Zone’, Scientific Reports, vol. 6.
Ashby, A 2026, ‘Legal perspectives on deep-sea mining: International Seabed Authority governance and closure gaps, with lessons from Australia’, in AB Fourie, G Boggs, J Heyes & M Tibbett (eds), Mine Closure 2026: Proceedings of the 19th International Conference on Mine Closure, Australian Centre for Geomechanics, Perth,
Ashby, AD, van Etten, EJB & Lund, MA 2016, ‘Pitfalls of gold mine sites in care and maintenance’, in AB Fourie & M Tibbett (eds), Mine Closure 2016: Proceedings of the 11th International Conference on Mine Closure, Australian Centre for Geomechanics, Perth, pp. 313–324,
Ashby, AD & van Etten, EJB 2021, 'Exploring abandoned mines through a public lens', in AB Fourie, M Tibbett & A Sharkuu (eds), Mine Closure 2021: Proceedings of the 14th International Conference on Mine Closure, QMC Group, Ulaanbaatar,
Australian Government 1999, Environment Protection and Biodiversity Conservation Act 1999, viewed 20 June 2026,
British Institute of International and Comparative Law 2023, Deep Seabed Mining and International Law: Is a Precautionary Pause Required?, London.
Centre for International Governance Innovation 2018a, Legal Liability for Environmental Harm from Deep Seabed Mining Activities, Waterloo.
Centre for International Governance Innovation 2018b, Writing International Laws for Deep Seabed Mining, Waterloo.
Collaboration for Environmental Evidence 2022, Guidelines for Systematic Reviews in Environmental Management, version 5.1, Bangor.
Commonwealth Scientific and Industrial Research Organisation (CSIRO) 2022, Deep-Sea Mining: Resource Potential, Technical and Environmental Considerations, Canberra.
Christiansen, S & Bräger, S 2023, ‘Developing best environmental practice for polymetallic nodule mining - a review of scientific recommendations’, Frontiers in Marine Science, vol. 10,
Craik, N 2020, ‘Implementing adaptive management in deep seabed mining: Legal and institutional challenges’, Marine Policy, vol. 114.
Chin, A & Hari, K 2020, Predicting the Impacts of Mining of Deep Sea Polymetallic Nodules in the Pacific Ocean: A Review of Scientific Literature, Deep Sea Mining Campaign & MiningWatch Canada.
Deep Sea Conservation Coalition 2026, Deep-Sea Mining: What the World Needs to Know – a 2026 Media and Policy Briefing Series, Deep Sea Conservation Coalition, Amsterdam, viewed 21 August 2026,
Deep Sea Conservation Coalition 2023, Deep-Sea Mining: Growing Support for a Moratorium, Deep Sea Conservation Coalition, Amsterdam, viewed 21 June 2026,
DSM_MORATORIUM_4pp_OCT_23.pdf
Department of Climate Change, Energy, the Environment and Water 2026, Environment Protection and Biodiversity Conservation Act 1999 Reforms, Canberra.
Devane, D, Hamel, C, Gartlehner, G, Affengruber, L & Garritty, C 2024, ‘Key concepts in rapid reviews’, Journal of Clinical Epidemiology, vol. 175.
Duarte-Kzam, D, Restrepo-Ochoa, DA, Alzate-Pamplona, JP, Giraldo-Giraldo, CA & Restrepo, S 2025, ‘Rapid reviews in environmental management’, Environmental Evidence, vol. 14, p. 12.
Durden, JM, Murphy, K, Jaeckel, A, Van Dover, CL, Christiansen, S, Gjerde, K … Weaver, PP 2018, ‘Environmental impact assessment process for deep seabed mining’, Marine Policy, vol. 87, pp, 197–202.
Elmore, A, Kehoe, K & Moreno, V 2025, State of the Science Fact Sheet: Deep Sea mining, National Oceanic and Atmospheric Administration, viewed 21 August 2026, vol. 87, pp. 194–202,
Fauna & Flora 2023, Update to “An Assessment of the Risks and Impacts of Seabed Mining on Marine Ecosystems”, Fauna & Flora International, Cambridge, UK.
Frontiers in Marine Science Editorial Team 2025, ‘Governance of deep-sea mining’, Frontiers in Marine Science, vol. 12.
Frontiers in Ocean Sustainability 2024, ‘Environmental impact assessment reform’, Frontiers in Ocean Sustainability, vol. 2.
Ganann, R, Ciliska, D & Thomas, H 2010, ‘Expediting systematic reviews’, Implementation Science, vol. 5.
Gollner, S, Colaço, A, Corinaldesi, C, Galil, B, Martins, I, Mestre, NC … Van Dover, CL 2025, ‘Deep sea ecosystem recovery and restoration feasibility’, Marine Policy, vol. 168.
Government of Western Australia 1978, Mining Act 1978, viewed 20 July 2026,
Graydon, H 2023, ‘Stewardship frameworks’, Marine Policy, vol. 155.
Guo, X, Dai, S, Zhao, L, Wang, X & Yan, X 2023, ‘Deep seabed mining’, International Journal of Coal Science & Technology, vol. 10.
Haddaway, NR, Macura, B, Whaley, P & Pullin, AS 2020, ‘ROSES reporting standards;, Environmental Evidence, vol. 7.
Hamley, GJ 2022, 'Implications of seabed mining', Review of European, Comparative & International Environmental Law, vol. 31, no. 2.
Haugan, PM, Levin, LA, Amon, DJ, Hemer, M, Lily, H & Nielsen, FG 2023, ‘What role for ocean-based renewable energy and deep-seabed minerals in a sustainable future?’, in J Lubchenco & PM Haugan (eds), The Blue Compendium: from Knowledge to Action for a Sustainable Ocean Economy, Springer, Cham, pp. 51–89.
Hein, JR, Koschinsky, A & Kuhn, T 2020, ‘Deep-ocean polymetallic nodules’, Nature Reviews Earth & Environment, vol. 1, pp. 158–175.
He, J, Wang, L, Liu, Y, Wang, Z, Xu, Z & Liu, R 2026, ‘Community-wide dynamics drive microbial degradation of halogenated organic pollutants in the Mariana Trench under in-situ relevant conditions’, Environmental Research, vol. 299, no. 124359.
Hunnicutt, T 2026, ‘Trump to speed permits for deep-sea mining in international waters’, Reuters, viewed 20 June 2026,
International Seabed Authority 2023, Regional Environmental Management Plan, Kingston.
International Seabed Authority 2013, Regulations on Prospecting and Exploration for Polymetallic Nodules in the Area, ISA/19/C/17, Kingston.
International Seabed Authority 2025, International Seabed Authority – 30th Session 2025.
International Union for Conservation of Nature 2022, Deep-Sea Mining, Gland.
Jones, DOB, Washburn, TW & Smith, CR 2020, ‘Deep-sea mining impacts’, Natural Capital and Exploitation of the Deep Ocean, Oxford University Press, Oxford, pp. 112–135.
Kaikkonen, L, Virtanen, EA, Kostamo, K, Simola, H & Viitasalo, M 2018, ‘Impacts of seabed extraction’, Marine Pollution Bulletin, vol. 135, pp. 411–423.
Levin, LA, Amon, DJ & Lily, H 2020, ‘Sustainability challenges’, Nature Sustainability, vol. 3, pp. 784–794.
Leyton-Flor, R & Sangha, K 2024, ‘Socio-ecological costs’, Resources Policy, vol. 91.
Lubchenco, J & Haugan, PM 2023, The Blue Compendium, Springer, Cham.
Mengist, W, Soromessa, T & Legese, G 2020, ‘Systematic review methods’, MethodsX, vol. 7.
Mining Reporters 2026, ‘Deep-sea mining race accelerates’, Mining Reporters, vol. 14, no. 2, pp. 12–15.
Miller, KA, Thompson, KF, Johnston, P & Santillo, D 2018, ‘Overview of seabed mining’, Frontiers in Marine Science, vol. 4.
Moons, KGM, Wolff, RF & Riley, RD 2021, ‘Critical appraisal’, Annals of Internal Medicine, vol. 174, pp. 311–318.
Mulà, C, Bradshaw, CJA, Cabeza, M, Manca, F, Montano, S & Strona, G 2025, ‘Restoration cannot be scaled up globally to save reefs from loss and degradation’, Nature Ecology & Evolution, vol. 9, no. 5, pp. 822–832,
Myers, J 2025, ‘Resource nationalism’, Extractive Industries and Society, vol. 22.
NOAA Ocean Exploration 2024, NOAA Ship Okeanos Explorer: 2024 expeditions overview, National Oceanic and Atmospheric Administration, Silver Spring, viewed 21 June 2026,
National Oceanic and Atmospheric Administration 2026, Deep Seabed Hard Minerals Mining, viewed 21 August 2026,
National Oceanic and Atmospheric Administration (NOAA) 2023, NOAA Ocean Exploration 2023 Expeditions, viewed 20 June 2026,
Oceanographic Magazine 2026, ‘ISA contractor non-compliance’, Oceanographic Magazine, no. 42, pp. 24–29.
Oztig, LI 2025, ‘Social science perspectives’, Ocean & Coastal Management, vol. 260.
Page, MJ, McKenzie, JE, Bossuyt, PM, Boutron, I, Hoffmann, TC & Mulrow, CD 2021, ‘PRISMA statement’, BMJ, vol. 372, no. 71.
Parliament of Australia 2025, Environment Protection Reform Act 2025, Commonwealth of Australia, Canberra.
Perkins Coie 2026, NOAA permitting implications, Perkins Coie LLP, Seattle.
Pecoraro, A 2019, ‘Deep seabed mining in the area: is international investment law relevant?’, Blog post, viewed 20 August 2026,
Petrossian, GA & Lettieri, J 2024, ‘Risks of deep-sea mining’, Marine Policy, vol. 162.
Pickens, C, Broadgate, W & Scholes, R 2023, ‘Governance gaps’, One Earth, vol. 6, pp. 411–419.
Planet Tracker 2023, Sea Bed Mining Economics, London.
Rosenbaum, H & Sharma, A 2023, ‘Adaptive management’, Marine Policy, vol. 148.
Sander, SG, Tamburini, C, Gollner, S, Guilloux, B, Pape, E, Hoving, HJ, L … & Narayanaswamy, BE 2025, ‘Deep sea research and management needs’, Future Science Brief No. 12, European Marine Board, Ostend,
Singh, PA & Jaeckel, A 2024, ‘Legal sufficiency’, International Journal of Marine and Coastal Law, vol. 39, no. 1, pp. 55–82.
Singh, PA, Warner, RM & Jabour, J 2025, ‘Moratorium debate’, Ocean Development & International Law, vol. 56, pp. 102–125.
Snyder, H 2019, ‘Literature review methodology’, Journal of Business Research, vol. 104, pp. 333–339.
Squillace, M 2021, ‘Lessons from land-based mining regulation’, Colorado Natural Resources Law Review, vol. 32, pp. 145–182.
Tibbett, M 2024, ‘Post-mining reconstruction’, Current Biology, vol. 34, pp. R112–R115.
The Metals Company 2026, TMC USA Files First Consolidated Deep-Seabed Mining Application, Increasing Expected Commercial Recovery Permit Area to 65,000 km², 22 January, viewed 20 June 2026,
Tunnicliffe, V, Sánchez, LE, Mudd, GM, Amon, DJ, Levin, LA, Lily, H, … Cross, AT 2025, ‘Metal mining on land versus the ocean in the context of the current biodiversity crisis’, npj Ocean Sustainability, vol. 4, no. 1.
Van Dover, CL 2011, ‘Tighten regulations on deep-sea mining’, Nature, vol. 470, no. 7332, pp. 31–33,
World Ocean Review 2014, World Ocean Review 3: Marine Resources — Opportunities and Risks, Maribus, Hamburg.
Wang, C, Shu, X, Zhou, S, Song, H & He, Q 2025, ‘Embracing a new era of deep-sea mining: Research progress and prospects’, Marine Policy, vol. 180,
Van Dover, CL, Aronson, J, Pendleton, L, Smith, S, Arnaud-Haond, S, Moreno-Mateos, D … Billett, D 2014, ‘Ecological restoration in deep sea’, Marine Policy, vol. 44, pp. 259–263.
United Nations 1982, United Nations Convention on the Law of the Sea, opened for signature 10 December 1982, 1833 UNTS 3, entered into force 16 November 1994, United Nations Treaty Collection.
Xu, X, Li, M & Xue, G 2023, ‘Revisiting the “responsibility to ensure”: two-line standards of the sponsoring state’s national legislation on deep seabed mining’, Sustainability, vol. 15, no. 10,




© Copyright 2026, Australian Centre for Geomechanics (ACG), The University of Western Australia. All rights reserved.
View copyright/legal information
Please direct any queries or error reports to repository-acg@uwa.edu.au