Sustainable Seas Contents

4Deep sea mining

56.Oceans that are more than 500m deep are referred to as the ‘deep sea’. The deep sea covers about 60 per cent of the Earth’s surface, hosting a diverse spectrum of geological environments, geomorphological features and ecosystems.182 Valuable minerals are known to be deposited at or near the surface of the deep seabed with potential societal and economic benefits. There are two classes of interest, minerals from mining of the deep-ocean floor and novel chemicals, particularly drugs, derived from the genetic diversity of marine life.183 Such deposits were first considered for extraction in the 1960s, but at that time it was technologically and financially unfeasible.184 There has been renewed interest in deep sea mining because of the growing demand for metals, the increasingly inaccessible and degraded land-based deposits and advances in marine submersible and mining technology.185 Deep seabed mining has not yet begun on a commercial scale but the Royal Society indicated that given technological and regulatory development it is possible that exploitation could begin in the next decade.186

Access to resources

57.Seabed mining within national jurisdictions is common, for example mining for diamonds off Namibia has taken place for decades, and this is permitted within a nation’s exclusive economic zone and where it has sovereign rights to the continental shelf (see figure 1).187 Resources in the deep sea are, by their nature, beyond the limits of national jurisdiction and are designated for the “common heritage of mankind” under the UN Convention of the Law of the Sea (UNCLOS) (see Annex A).188 Exploration and exploitation activities in the high seas (or Area Beyond National Jurisdiction (ABNJ)) are regulated at the international level by the International Seabed Authority (ISA), which was established under UNCLOS. ISA has established regulations for mineral exploration and is currently developing regulations for exploitation. As a party to UNCLOS, the UK can bid to ISA for mining rights in the high seas.

Figure 1. Jurisdictional zones from a nation’s coast. 1 nautical mile = 1852 metres. Courtesy of the Royal Society.189

58.At present, no international organisation has the mandate to regulate access to marine genetic resources beyond national jurisdiction, which currently falls under an open access regime based on “the freedom of the high seas”.190 Preparations are under way for a legally binding instrument on biodiversity in areas beyond national jurisdiction within the UN High Seas Treaty (see Chapter 6). We focussed our inquiry on the environmental risks associated with the exploration and extraction of deep sea minerals and how they can be mitigated.

Opportunities from deep sea mining

59.Minerals are vital to support economic growth and the functioning of modern society, for example ‘critical’ metals (rare earth elements, cobalt, tellurium) used in high technology and clean energy applications.191 UK Seabed Resources Ltd suggests that polymetallic nodules could generate a secure and predictable supply for UK industry of minerals which are increasingly at risk of global supply disruption.192 Environment Links UK claims that deep sea mining runs contrary to our Sustainable Development Goal commitments on sustainable consumption and production and to conserve and sustainably use the oceans (SDGs 12 and 14).193 Will McCallum, Head of Oceans at Greenpeace, considered that there are other sources of the materials found on the seabed available on land and that these should be exploited first:

One hundred and sixty million mobile phones are thrown away every single year in Europe. Those mobile phones are all packed with exactly the same materials that we are being told we need to go out to the deep sea and mine for. At the very least we need to start looking at this more holistically and so I would say, until the conclusion of the treaty, put those ambitions for deep sea mining totally on hold and conduct this investigation.194

60.Michael Lodge, Secretary General of ISA, told us that the minerals were not only needed for mobile phones but to drive a “future renewable economy” including wind turbines and electric cars which need “a tremendous amount of these critical minerals”. He said that the grades in the sea are many orders of magnitude higher than the grades on land.195 However he described deep sea mining as “almost as difficult as going to the moon”.196 The Royal Society’s synthesis of current evidence concluded that although the deep sea offers huge potential for the extraction of metals, “a lack of exploration and data results in great uncertainty about the total size of the resource and its economic value”.197 When questioned on the need for deep sea mining, Claire Perry responded that the Department for Business, Energy and Industrial Strategy is building the economic case for extracting minerals from the seabed and has commissioned independent analysis which will report in early 2019.198

Environmental risks and their mitigation

61.Deep sea mining presents risks such as the physical destruction of habitats and organisms as well as changes to light and noise levels, which can impact on ecosystem function and the ability for species to communicate.199 We heard that this can cause local extinctions.200 Mining also disturbs the seabed causing sediment plumes which can travel considerable distances and smother seabed organisms.201 Plumes can also be caused when mining waste is returned to the water, which remains suspended above the seabed in the water column.202

62.Deep sea mining is currently targeting three types of minerals that are found in distinct deep sea habitats that vary greatly in area, biodiversity and ecological dynamics:

63.Dr Jon Copley from the University of Southampton, told us that given the ecological differences between these deep sea habitat types, each is likely to respond very differently to the impacts of mineral extraction activities.204 ISA has approved 29 contracts for exploration for all three types of minerals in the deep seabed.205 UK Seabed Resources Ltd, sponsored by the UK Government, holds two of these exploration licences for polymetallic nodules in the Pacific Ocean’s Clarion Clipperton Zone (CCZ), which it hopes to commercially harvest in future.206

64.Under ISA’s exploration regulations, an Environmental Impact Assessment (EIA) is mandatory. Professor Mills from the University of Southampton suggested that the difficulty of undertaking an EIA two miles beneath the sea’s surface has been underestimated. The University of Southampton is concerned that the environmental impacts of one site may be small in scale but that the cumulative impacts are unknown and difficult to predict. It suggests that an EIA may not be able to scale up these small-scale and laboratory experiments adequately.207 Professor Henderson from the Royal Society advocated that a regional management approach is needed rather than a local impact assessment.208

65.ISA told us it is addressing the challenge of planning at the regional scale by progressively developing Regional Environmental Management Plans (REMPs) in all areas where exploration activity is taking place. The first REMP, was created for the CCZ which designated a network of nine Areas of Particular Environmental Interest (APEIs), where mining will not be permitted to take place.209 ISA told us it is in the process of developing REMPs for the Mid-Atlantic and Western Pacific Oceans.210 The National Oceanography Centre told us APEIs are presumed to be geographically close enough to mining sites to allow for biological connectivity with the proposed mining areas, so that re-colonisation can occur after mining has ceased.211 Professor Mills explained that there was no knowledge of whether this approach would work:

We do not know whether they are big enough to be useful for recolonisation of the potentially mined sites, and we do not even know what timeframe those ecosystems are reproducing on. We do not even know what role the hard substrate of the manganese nodules holds for the life cycle of those organisms living near the seafloor.212

Professor Henderson also stressed the lack of knowledge of the deep sea, he considered that “a sense of the diversity of the ecosystem, regionally and spatially” is missing at present.213 He said:

it is doubtless true that exploitation of a very small fraction of the deep ocean floor might cause catastrophic damage to that point, but it would not cause catastrophic damage to the whole deep ocean ecosystem. If you were to mine a very substantial area it would and the question is: how much might you be able to mine without causing very substantial environmental impact?214

66.Professor Mills was also concerned that there was no independent body to monitor the impact of the industry.215 The National Oceanography Centre pointed out that ISA is responsible for the environmental impacts and their mitigation, and the sharing of the revenues that may flow from deep sea mining.216 Will McCallum also noted this and believed it was a conflict of interest.217

Unique habitats

67.Charles Clover, representing the Great British Oceans coalition,218 was critical of ISA for allowing exploration in unique habitats such as hydrothermal vents on the mid-Atlantic ridge:

The problem at the moment is that the International Seabed Authority has been granting exploration licences in places that on land would be world heritage sites. They have given Poland, I think it is, permission to explore the Lost City, which is one of the seven wonders of the world in the deep sea.219

Professor Henderson agreed that the Lost City is “a treasure of the deep sea”.220 Areas of massive sulphides are often unusual environments and there is a risk that they may be unique, so mining one of them will cause catastrophic damage.221 Dr Copley described that in a survey of deep sea hydrothermal vents on the Southwest Indian Ridge, (where the ISA had already granted an exploration licence) he discovered six previously undescribed animal species not yet known elsewhere on Earth, and a unique combination of species resulting in an “ecologically distinct community” compared with other known hydrothermal vents.222 He said that there is insufficient understanding of the variation in marine life between vent sites to inform effective regional management plans.223 We heard that although exploration is most advanced for polymetallic nodules on abyssal plains, mining of hydrothermal vents is closest to commercial success.224

68.Claire Perry said the Government’s view of deep sea mining is evolving and that the “idea of flattening seamounts, scraping seabeds, having impacts on fishery stocks and other challenges are to be answered”.225 We asked whether she would rule out exploration in special sites such as hydrothermal vents. She responded:

This will depend on the results of further environmental analysis; on having a clear economic case; the necessary metrics, measures and inspection regimes, and an agreed commercial policy. All of these elements are in play at the moment.226

69.Both Lord Ahmad and Claire Perry recognised the role the UK can play internationally within ISA and the UN:

Lord Ahmad: On the example you have raised of the Lost City, we have to learn from the experience of exploration and then exploitation and techniques. With the current discussions that are happening at the ISA and through the [UN negotiations on the conservation and sustainable use of marine biodiversity of areas beyond national jurisdiction] and with the specific discussions on looking at those jurisdictions beyond national boundaries, it is important that we not only have a voice on that but show leadership.227 […]

Claire Perry: If we can establish a gold standard of environmental principles, we can have an important leadership role, as we did in the discussions around Antarctica and exploitation on the continent in the 1940s.228

70.Deep sea mining would have catastrophic impacts on the seafloor site and its inhabitants. We heard that Environmental Impact Assessments are very difficult to undertake for the deep sea and that there was little evidence that mitigation measures such as setting aside areas of the seafloor will mitigate the damage and allow for the recolonisation of habitats and species recovery. Licences have been granted by the International Seabed Authority to permit exploration in unique habitats, but we consider the exploitation of resources must be prohibited in unique ocean environments, such as hydrothermal vents, until it can be determined that adequate mitigation techniques are available. We are concerned that the ISA, the licensing body for seabed exploration, also stands to benefit from revenues, which is a clear conflict of interest. The Government must commit not to pursue licences for polymetallic sulfides/ seafloor massive sulfides found at active hydrothermal vents within its own jurisdiction and internationally. The UK should utilise its substantial experience in regulating marine industries and its influence with the International Seabed Authority (ISA) to impose a moratorium on exploitation licences in these areas as ISA develops its exploitation guidelines. Outside of these unique areas, the Government should proactively work with ISA to ensure Environmental Impact Assessments are robust, based on the precautionary principle and use the best available scientific evidence.

71.The case for deep sea mining has not yet been made. We welcome the Government’s review on the economic case for extracting minerals from the seabed. This should include a full review into the necessity for deep sea mining for rare earth metals, based on the availability of these materials in old and discarded products.


182 Glover AG, Smith CR. The deep sea floor ecosystem: current status and prospects of anthropogenic change by the year 2025. Environ Conserv. 2003 Sep; 30(3): 219–241, cited in Royal Society. 2017. Future Ocean Resources: metal rich minerals and genetics evidence pack

184 Mero, J. 1965. The Mineral Resources of the Sea, Elsevier, New York, US

185 Deep Sea Mining, POSTnote 508, Parliamentary Office of Science and Technology, September 2015

186 International Seabed Authority (SSI0142); The Royal Society (SSI0122)

187 UK Seabed Resources Ltd (SSI0118); The National Oceanography Centre (SSI0079)

188 International Seabed Authority (SSI0142)

192 UK Seabed Resources Ltd (SSI0118); see also Q318

193 Environment Links UK (SSI0102)

196 Q317; see also Q303 [Will McCallum]

199 Ocean and Earth Sciences, University of Southampton (SSI0088); Deep Sea Mining, POSTnote 508, Parliamentary Office of Science and Technology, September 2015

201 EU ATLAS Project (SSI0037); Ocean and Earth Sciences, University of Southampton (SSI0088); Deep Sea Mining, POSTnote 508, Parliamentary Office of Science and Technology, September 2015

202 Deep Sea Mining, POSTnote 508, Parliamentary Office of Science and Technology, September 2015

203 Dr Jon Copley (SSI0050)

204 Dr Jon Copley (SSI0050)

205 Qq313–314; See International Seabed Authority (SSI0142) for a full breakdown of licences

206 UK Seabed Resources Ltd (SSI0118)

207 Ocean and Earth Sciences, University of Southampton (SSI0088)

209 Q332; International Seabed Authority (SSI0142)

210 Q332; International Seabed Authority (SSI0142)

211 The National Oceanography Centre (SSI0079)

216 The National Oceanography Centre (SSI0079)

218 A coalition of the Blue Marine Foundation, Greenpeace, Marine Conservation Society, The Pew Trusts, RSPB and Zoological Society of London

219 Q304. The ‘Lost City’ is a hydrothermal field of 60 giant chimney structures, up to 250 feet tall, formed by hot mineral water pouring out of volcanic vents in the seabed. In 2017 ISA approved a 15-year exploration contract with Poland, covering part of the Mid-Atlantic Ridge.

222 Dr Jon Copley (SSI0050)

223 Dr Jon Copley (SSI0050)

224 Dr Jon Copley (SSI0050)




Published: 17 January 2019