ISSUES NOTE
6 May 2024

Deep-Sea Mining
The environmental implications of deep-sea mining
need to be comprehensively assessed.

The United Nations Environment Programme (UNEP) is the leading global environmental authority that sets
the global environmental agenda, promotes the coherent implementation of the environmental dimension ofsustainable development within the United Nations system and serves as an authoritative advocate for the
global environment with a mandate to keep the environment under review.1
1. Deep-sea mining (DSM) is a proposed commercial industry that includes the exploitation (mining) of
mineral deposits and metals from the deep-seabed. The process starts with prospecting and explorationand ends with the refining of ores, which is proposed to be undertaken on land. There are three types ofdeep-sea mineral deposits of commercial value between <400m and 6.5km:
a. Polymetallic nodules: underwater (abyssal) plains with nickel, manganese, copper and cobalt andrare earth elements (REE considered sub products) at depths of between 3 and 6.5km;
b. Polymetallic sulphides: may be located in the vicinity of vents at depths of between 1 and 4 km andwith concentrations of copper, lead and zinc as well as gold and silver; andc.

Cobalt rich ferromanganese crusts: between <400m and 3.5km on seabed also with nickel, copperand cobalt and REE and other rare metals.

This Issues Note provides a review of the latest literature on specific topics that are of relevance to UNEP’s mandate as outlined in “Thefuture we want: outcome of the Conference on Sustainable Development, Rio de Janeiro, Brazil, 20-22 June 2012; paragraph 88”. It alsopresents a set of agreed approaches and recommendations regarding UNEP’s communication of the subject matter.
12. Proponents of deep-sea mining are advocating that DSM is needed to meet the expected increased
demand for critical minerals and metals to support low and zero carbon initiatives, as well as to address
the environmental and social impacts and potential supply disruption vulnerabilities associated withterrestrial mining (International Energy Agency [IEA] 2022). Proponents and researchers suggest ores inthe deep-seabed have higher concentrations of minerals and metals (Hein et al 2013; Katona et al 2023) andmay require less significant technological innovations to achieve efficiency, specifically for the extraction ofpolymetallic nodules (Hein et al 2020). Under some scenarios, DSM is considered to have less impact on theenvironment and human health compared with traditional mining practices.² These assertions have not yet
been confirmed with scientific evidence.
3. Significant concerns have been raised by all sectors including governments and researchers about thepotential environmental impacts. In addition, questions have been raised regarding whether or not demand
will indeed rise to such levels that warrants the use of DSM, and whether resources can be supplied throughmore efficient processing and refining of terrestrial deposits, recycling and circularity efforts.³
4. Much of the deep-seabed is unexplored (Van Dover et al 2018) with only an estimated 24.9 per centhaving been mapped.4 What is known suggests its ecosystems are unique, fragile and diverse, hence there
could be many potential environmental impacts of DSM on these ecosystems. Globally, these ecosystems
are also considered crucial to ocean and carbon cycling and likely vulnerable to the effects of climate change(Levin et al 2020). There are no known commercial operations currently in place (International Seabed
Authority [ISA] 2021), hence, potential changes in the environment can only be predicted from impacts
observed due to exploration, trawling and infrastructure associated with oil and gas activites.
5. There are calls from civil society, business, governments5 and IGOs (International Union for Conservationof Nature [IUCN] 2021) for a pause on DSM applications / approvals by governments and the International
Seabed Authority (ISA) as well as calls for a moratorium on deep-sea mining. A broad range of private sector
organizations have joined a public statement supporting a moratorium and committed not to use metals
produced from deep-sea mining until the “environmental, social and economic risks of deep-seabed mining arecomprehensively investigated”. DSM was also considered by the Convention on Migratory Species that decided
at its recent COP14 to “Urge Parties not to engage in, or support, deep-seabed mineral exploitation activities
until sufficient and robust scientific information has been obtained to ensure that deep-seabed mineral
exploitation activities do not cause harmful effects to migratory species, their prey and their ecosystems”.6
6. In areas beyond National Jurisdiction, the UN Convention on the Law of the Sea (UNCLOS) and the 1994
Agreement mandate the ISA to manage all mineral-resources-related activities in the ‘Area’7 for the benefitof humankind while ensuring the effective protection of the marine environment from harmful effects
that may arise from deep-seabed-related activities, fostering marine scientific research in the ‘Area’, andpromoting technology transfer to developing countries. Accordingly, ISA8 has been coordinating the process ofdeveloping regulations on the exploitation of the deep-seabed since 2014.

Concerns about land-based mining include the mining of lower quality ores; increasing energy needs and waste; exposure to climate events that are
greater when mining is in areas where there is pressure on water resources (particularly in copper and lithium mines which are water heavy processes)(IEA 2022). Other issues are the risks of disruption to supply chains, such as increases in floods, trade restrictions and conflict due to the extraction andprocessing of minerals and metals being concentrated in a few countries (e.g. China, Democratic Republic of the Congo, South Africa, Australia), factors
which increase supply vulnerabilities and resource availability concerns. Illegal activities have also been raised as an issue (United Nations Office on Drugs
and Crime [UNODC] 2023).
2

Deep-Sea Mining: assessing evidence on future needs and environmental impacts, European Academies’ Science Advisory Council, https://easac.eu/
fileadmin/user_upload/EASAC_Deep_Sea_Mining_Web_publication_.pdf.
3

4 Seabed 2030, https://seabed2030.org/our-mission/.
5 https://www.pewtrusts.org/en/research-and-analysis/fact-sheets/2023/06/seabed-mining-moratorium-is-legally-required-by-un-treaty-legal-experts-find.
6 Deep-Sea Mining, UNEP/CMS/COP14/CRP27.2.4/Rev.1, Retrieved from https://www.cms.int/en/document/deep-sea-mining-1.
7 ISA primary function is to regulate exploration for and exploitation of deep-seabed minerals found in the ‘Area’, which is defined by the Convention as theseabed and subsoil beyond the limits of national jurisdiction, that is, beyond the outer limits of the continental shelf. The ‘Area’ comprises just over 50 per centof the entire seabed on Earth.
8 In July 2023, the International Seabed Authority Council continued discussion on the development of the exploitation regulations (ISA 2023). The Council
agreed to set a deadline for finalization of negotiations and adoption of the regulations to 2025, whilst acknowledging that any application for exploitation
which may be submitted before these regulations are adopted would be considered as per the provisions of UNCLOS and subsequent 1994 Agreement.

2

7. A new agreement under the UNCLOS on the Conservation and Sustainable Use of Marine Biological
Diversity of Areas beyond National Jurisdiction (BBNJ Agreement) was adopted on 19 June 2023.9
UNEA6 acknowledged the adoption of this Agreement and requested the Executive Director to, within
UNEP’s mandate, provide assistance to Division for Ocean Affairs and Law of the Sea (DOALOS), as theinterim secretariat of the BBNJ to promote better understanding of the BBNJ Agreement.10
8. Locations not in the ‘Area’ are those maritime zones where states have national jurisdiction, including
exclusive rights over natural resources. This includes exclusive economic zones or ’EEZ’ - areas of the ocean
extending up to 200 nautical miles from a nation’s baselines. Some nations are now considering DSM in thesezones. For example, Norway has announced the review of environmental, social and economic impacts toestablish the feasibility of exploiting minerals resources in the deep sea in its national waters while protecting
the ocean environment.11
9. The environmental, social and economic impacts of exploiting the deep-seabed are uncertain andpotentially grave. Any decision on whether and how the deep-seabed may be exploited must be based on adetailed assessment of all available scientific evidence and take into account the precautionary principle. On
this basis, and with the view to keeping the environment under review, UNEP recommends:
a. A review of the status of DSM activites including country initiatives in EEZ and the ‘Area’, availability ofbaseline data and EEZ associated legislation and proposed approaches for terrestrial processing of
DSM minerals and metals.
b. A comprehensive analysis is undertaken of existing marine-related environmental and social data
and research, in concert with relevant UN agencies, Multilateral Environmental Agreements (MEAs),
Member States and relevant stakeholders, to inform future environmental impact assessment
processes addressing the potential exploitation of the deep-seabed. This comprehensive analysis
would address the potential impacts of DSM on marine and terrestrial ecosystems and the delineationof marine protected areas.12c.

A common reporting framework for valuation of ecosystems across EEZ and the ‘Area’.

d. That enhanced policy and technical support be provided to the increased uptake of resource andmaterials efficiency from current terrestrial mines, circular use of minerals, more responsible mining
practices and consumption choice. All of which are to drive innovation and the use of technologies
to access metals and minerals from legacy contaminated areas, tailings dumps and dams to meetdemand, as envisaged in the UN Secretary General’s Initiative on critical energy transition minerals.

9 United Nations Convention on the Law of the Sea, Agreement under the United Nations Convention on the Law of the Sea on the Conservation andSustainable Use of Marine Biological Diversity of Areas Beyond National Jurisdiction, retrieved from https://www.un.org/depts/los/bbnj.htm.
Strengthening ocean efforts to tackle climate change, marine biodiversity loss and pollution, UNEP/EA.6/RES.15, Paragraph 3(g), retrieved from https://
undocs.org/UNEP/EA.6/L.18.
10

The Norwegian Ministry of Energy is required to carry out an Environmental Impact Assessment (EIA) as per the Norwegian Seabed Minerals Act. A national
programme for EIA was developed in 2021 and aims to identify potential impacts on the environment and considerations of commercial, economic andsocial impacts. A number of baseline reports have been published by the Norwegian Government covering environmental conditions in the broad area underconsideration for seabed mining, as per the Environmental impact assessment, Norwegian Offshore Directorate, Retrieved from https://www.sodir.no/en/facts/
seabed-minerals/environmental-impact-assessment/
11

Such an analysis may include consideration of the following: i) impacts on deep sea ecosystems; ii) existing data on the impacts of exploration and trawling
and assessment of gaps in baseline data; iii) standardizing and innovating methodologies for deep-sea biodiversity assessment, including taxonomic identification and description in the Area; iv) Facilitating technology development that is sensitive to marine ecosystems impacts for activities in the ‘Area’, including
ocean observation and monitoring; v) promoting dissemination, exchange and sharing of marine environmental scientific data and deep-sea research outputs
and increasing deep-sea literacy; vi) strengthening deep-sea environmental science capacity, in particular developing states; vii) the potential impacts of
DSM across the lifecycle specifically addressing the potential impacts of terrestrial components giving consideration to energy, water, health and biodiversity
impacts; viii) comparative assessments of the environmental impacts of terrestrial mining which include environmental, economic, social and public health issues; ix) the status of / and opportunities for technologies for achieving circularity in the minerals value chain; x) the impacts on all developing economies andtrade and a just transition to low or no carbon economy; xi) the delineation of marine protected areas as outlined in the recently agreed BBNJ Treaty; xii) humanand environmental rights implications of DSM; and xiii) the development of clear environmental impact assessment processes including identification of areasof critical and ecosystem importance, and processes and technologies that minimize impacts across the lifecycle.
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References
Hein, J. R., Mizell, K., Koschinsky, A. and Conrad, T. (2013) Deep-ocean mineral deposits as a source of critical metals for high- and greentechnology applications: Comparison with land-based resources. Ore Geology Reviews 51, Pages 1-14, ISSN 0169-1368. https://doi.
org/10.1016/j.oregeorev.2012.12.001.
Hein, J. R., Koschinsky, A. and Kuhn, T. (2020). Deep-ocean polymetallic nodules as a resource for critical materials. Nature Reviews Earth& Environment 1, 158–169. https://doi.org/10.1038/s43017-020-0027-0.
International Energy Agency (2022) The role of critical minerals in clean energy transitions. Last access: 4 July 2023.
International Seabed Authority (2022). Technical Study 32. Study of the potential impact of polymetallic nodules production in the Area
on the economies of developing land-based producers of those metals which are likely to be most seriously affected.
International Seabed Authority (2023). Draft regulations on exploitation of mineral resources in the Area. Last access: 4 July 2023.
International Union for Conservation of Nature (2021). IUCN Director General’s open letter to ISA Members on deep-sea mining. Last
access: 4 July 2023.
Katona, S., Paulikas, D., Ali, S. Clarke, M., Ilves, E., and Lovejoy, T. E. et al. (2023) Land and deep-sea mining: the challenges of comparing
biodiversity impacts. Biodiversity and Conservation 32, 1125–1164. https://doi.org/10.1007/s10531-023-02558-2.
Levin, L. A., Amon, D. J. and Lily, H. (2020). Challenges to the sustainability of deep-seabed mining. Nature Sustainability 3, 784–794;
https://doi.org/10.1038/s41893-020-0558-x.
United Nations Office of Drugs and Crime (UNODC) (2023). Illegal Mining and trafficking in minerals. https://sherloc.unodc.org/cld/
uploads/pdf/Illegal_Mining_and_Trafficking_in_Metals_and_Minerals_E.pdf.
Van Dover, C. L., Arnaud-Haond, S., Gianni, M., Helmreich, S., Huber, J. A., Jaeckel, A. L. et al. (2018). Scientific rationale and international
obligations for protection of active hydrothermal vent ecosystems from deep-sea mining. Marine Policy 90, 20-28; https://doi.
org/10.1016/j.marpol.2018.01.020.

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