Deep-Sea Mining: Environmental and social considerations and risks
The deep sea could be one answer to the shortage of critical materials needed for a transition to low-carbon technologies. However, there are many unknown risks that come with this nascent industry and below I explore some key environmental and social considerations against the context of what is currently understood about deep sea mining.
By Tom Mills, Founder & Managing Director of Two Oceans Strategy, London, UK.
tom.mills@twooceansstrategy.com
www.twooceansstrategy.com

The global demand for metals and minerals is projected to double or even triple by 2050. Production of battery metals such as graphite, lithium and cobalt will have to increase by nearly 500% to meet the growing demand for clean energy technologies.
Simultaneously, supply to meet this demand from easy-to-reach terrestrial mineral sources is constrained by declining ore grades, geo-economic instability or ESG risks. This situation makes terrestrial mineral production increasingly difficult and expensive. In fact, ESG risks are the top-ranked risk to mining businesses in 2022, according to EY’s annual survey of mining company leaders.
Against this increasingly challenging backdrop, governments and companies are looking to alternative options to extracting minerals from the land, including the deep-sea and even asteroids. Society, governments, and companies are faced with a tradeoff between meeting mineral demands from increasingly challenging political, social and environmental contexts.
The deep sea could be one answer to the shortage of critical materials needed for a transition to low-carbon technologies. However, there are many unknown risks that come with this nascent industry and below I explore some key environmental and social considerations against the context of what is currently understood about deep sea mining.

Deep-Sea Mining: The Commercial Driver
Deep sea mining (DSM) involves the retrieval of minerals and deposits from the ocean floor at depths of 200 meters or greater. There are three main types of mineral resources that can be mined from the deep sea: polymetallic nodules, cobalt-rich crust, and polymetallic sulphides or vents. Polymetallic nodules, the best studied of these three types, usually exist unattached on the sea floor and are rocks rich in cobalt, nickel, copper, and manganese.
They are found in the highest intensity in the Indo-Pacific Ocean. To date, DSM has been restricted to exploration activities and the earliest estimated start date of commercial production of DSM is late 2024. The metals found on the seabed could be enough to electrify 280 million vehicles according to The Metals company, with claims that DSM will also result in less significant environmental and social impact compared to terrestrial mining. An industry-funded white paper also suggests there will be fewer social impacts and lower lifecycle greenhouse gas emissions than terrestrial mining.
Another obvious driver for DSM is its emerging commercial proposition. Industry expert, Sharma, estimates the commercial value of polymetallic nodules in a 75,000 sq km seabed area at USD$21bn, for an investment cost of $14bn over a 20-year period. Private enterprises and states alike would be expected to share the profits of such an enterprise, whether by sale or by taxes, royalties, levies, or other financial mechanisms.
Environmental considerations: The great unknown
Despite the surface-level appeal of deep-sea mining and obviously lucrative potential of the industry, risks to the environment and people are not well-defined. Within academic literature, there are research indicating the fragility of deep-sea ecosystems, their slowness to recover from disturbance, and the paucity of data informing understanding of the seafloor is abundant.
Even where progress has been made with environmental research, thorough analyses will be needed on environmental impacts specific to any contract area. As it stands, there are known areas of ecological or biological significance in the Central Indian Ocean Basin and the Clarion Clipperton Zone. Dr A Kung also encourages states and DSM companies to consider the wider environmental impacts, for example, the impacts of onshore processing, including waste rock generation and disposal.
The impact of deep-sea mining, in terms of the planet’s biological systems, the seabed’s role as a carbon sink and the potential opportunities for new biomedical developments from species in the deep is almost entirely unknown and unresearched. At the same time, Deep Sea Mining has become an extremely contentious issue, with several of the world’s largest companies and governments issuing moratoriums on minerals mined from the deep sea. This may have a bifurcating impact, splitting supply chains that accept deep sea mined minerals and those that do not.
On solution put forward by the International Seabed Authority, the governing body for deep sea mining in international waters is the use of an Environmental Impact Assessment (EIA). However, EIA rests on the logic that environmental impacts can be predicted and assessed, whereas for DSM uncertainties such as the ongoing development of technologies and lack of projects that serve as a precedent present challenges to this method.
This is not the only issue at play; other uncertainties to consider are the complex nature of seafloor sites, which could mean a sample may not represent the whole site accurately. The slow-changing, fragile nature of seafloor ecosystems also makes it likely that any harm will take substantial time to naturally repair.
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Social Considerations: The issue of measuring indirect risk
Some direct social impacts that come to mind when considering deep sea mining are risks of physical disturbances to land, coastlines, and infrastructure. This could be caused by processing facilities, waste disposal, and increased shipping requirements. Further, depending on the project there might be competing uses of land and water amongst marine parks and recreational areas, shipping zones, fisheries, subsea telecommunication infrastructure, and ports.
The impacts deep sea mining will have on fish, water and air quality and noise will also have consequential effects on people. Assessing these direct, physical activities risks to people is relatively straightforward. By contrast, indirect social risks are currently being debated and have not yet been resolved. Two particular social impacts are free, prior, and informed consent (FPIC) and economic extension of the idea of acceptance:
FPIC originates in Indigenous Peoples’ rights and stems from the recognition that governments and private parties should obtain the free, prior, and informed consent of Indigenous people when seeking to undertake a project on Indigenous land. Neither FPIC nor a social licence to operate have a formal approval process. Anthony Kung et al prelude to in the 2021 research paper – Governing deep sea mining in the face of uncertainty – even within terrestrial mining it is unclear as to how either can be obtained, maintained, or proven.
For instance, we have to ask the question: who constitutes the host community? Other than those with formal power, such as landowners themselves, who may effectively veto a project by withholding consent? How is many people’s withholding required for a government regulator to decline to approve it?
These answers are not yet solved and will need to be on a project-by-project basis for communities to be protected and social rights to be properly administered. For terrestrial mining, connection to the land is the basis for FPIC and social licence.
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My concern with DSM is there is no such connection as no one lives on the seafloor. Yet, deep cultural connections to the ocean are prevalent across the globe and figuring out the correct way to weigh in these connections will be vital. Secondly, multinational companies – including BMW, Volkswagen, Renault, Google, and Samsung– have declared a moratorium on using DSM metals in their products.
The World Economic Forum has also started a deep-sea mining ‘dialogue’ platform to discuss the extension of responsible sourcing standards to DSM. These developments raise questions for deep sea miners as to whether the metals will have a beneficial place for real-world use and perform to accelerate a green transition, as was originally hoped.
Considering the potential demand for the resources that will power the green transition and the lucrative character of deep-sea resources that have been understood to exist, pressure to accelerate commercial mining projects is unsurprising. While some experts say we must mine the deep sea to combat climate change, I would argue that as it stands, we know too little about the potential damage to the environment to readily consider mass-commercial expeditions. However, I do not think the industry should be pushed aside or coined as evil.
The strength of the governance regime and how it is administered will ultimately be the determining factor of whether the liberation of resources from the seabed positively or negatively contributes to the common heritage of mankind. The International Seabed Authority has the weight of the world’s oceans on its shoulders.