A science-based critique of An assessment of the risks and impacts of seabed mining on marine ecosystems

We have reviewed Flora and Fauna International’s (FFI) 2020 publication, An assessment of the risks and impacts of seabed mining on marine ecosystems, by Pippa Howard, Guy Parker, Nicky Jenner and Twyla Holland and would like to offer the following comments for your consideration.

We respect FFI’s status as the world’s oldest international wildlife conservation organization. We appreciate and applaud its goal, as stated in the Public Benefit section of its 2018 Annual Report: “We strive for a sustainable future for the planet for the benefit of the public and act to conserve threatened species and ecosystems whilst taking account of human needs.” Above all, we celebrate FFI’s remarkable historical and current achievements toward that goal.

The authors of the recent assessment provided an excellent summary of many issues surrounding deep-sea mining, particularly the description of the different types of deep-sea mining under consideration, the general discussion of the types of risks involved, and the analysis of the status of governance in waters within and beyond national jurisdiction.

However, we are writing to suggest that their call for a moratorium on deep sea mining be modified to account for the special circumstances of polymetallic nodules.

Particularly in light of the urgent, time sensitive needs outlined by the UN’s Intergovernmental Panel on Climate Change’s (IPCC) (2018) Special Report to correct the imbalance we humans have created in the Earth-Atmosphere-Human-Ocean planetary system, we believe there is another path, a practical route that acknowledges with more precision the distinctions between  different types of seabed mining, and one that balances more satisfactorily the concerns identified in the FFI report with the IPCC’s call to action.

Given (1) the urgent necessity of mitigating climate change rapidly, (2) the high potential of polymetallic nodules to also contribute to other environmental and human goals, (3) the relatively low abundance and species richness found on the CCZ seafloor compared to that on land, and (4) the high likelihood that use of nodules would support FFI’s interest in sparing high-diversity land areas from being mined, we recommend that any proposed moratorium does not include polymetallic nodules in the CCZ.

(1) Urgent necessity to mitigate climate change rapidly

For the last 18 months, we have worked with The Metals Company (formerly DeepGreen Metals) to help answer the question: ‘Where should metals for the green transition come from?’ We prepared a cradle-to-gate[1] life cycle assessment of the environmental, social, and economic impacts of sourcing the base metals (manganese, copper, nickel and cobalt) to build batteries for 1 billion electric vehicles (EV) from land ores vs. polymetallic nodules collected from the abyssal seafloor of the Clarion Clipperton Zone (CCZ) in the northeast Pacific Ocean. We have attached a copy of that report along with this letter.

We focused on a key source of greenhouse gas emissions, transportation, which is responsible for 14% of emissions globally and 19% in the U.S. Converting automotive transportation from fossil-fuel dependent internal combustion engines to emission-free electrical power would therefore be a major contribution to the green transition and to the reduction of planetary warming.

The overriding impetus for our report is the Intergovernmental Panel on Climate Change’s (IPCC) (2018) Special Report on Global Warming of 1.5°C, which states that humans can put no more than 420 gigatonnes (billion metric tons) of carbon dioxide (CO2) into the atmosphere between 2018 and 2050 in order to have a 66% probability of not exceeding a temperature increase of 1.5°C.

However, in 2018 alone, we emitted 37 gigatonnes—nearly 10% of our total remaining budget—and in 2019 human activities released 43.1 gigatonnes, ‘spending’ another 10% of that budget. At our current emissions rate, we will exceed the 420 gigatonne carbon limit by 2030 and reach a 3°C temperature rise by 2100. A 3°C increase would likely raise global sea-level by 10 cm higher than what is projected for a 1.5°C temperature rise. Instead of a 70% to 90% decline in coral reefs, we would lose virtually all of them and the 25% of all marine life they contain. Even the difference between 1.5°C and 2°C would be dramatic.

The only pathway to avoid overshooting a 1.5°C rise in average global temperature is reducing CO2 emissions by 45% below 2010 levels by the year 2030 and reaching net zero by 2050, at which time continuing global greenhouse gas (GHG) emissions would need to be offset by actively pulling gigatonnes of emitted CO2 out of the atmosphere.

Given this unrelenting scenario, the reduction of every possible gigatonne of emissions is urgent. Our analysis found that sourcing metals for 1 billion batteries from nodules on the CCZ seafloor would save more than 1 gigatonne of direct emissions of CO2 and also avoid release of up to ~9 gigatonnes of sequestered carbon.

(2) Polymetallic nodules’ potential to aid other environmental and human goals

In addition, as shown in the table below, we found that sourcing from nodules would reduce water use, solid waste, ecotoxicity, human toxicity, air pollution by sulfur and nitrogen oxides, and human fatalities, injuries and illness by 90% or more. It would also completely avoid child labor and impact on indigenous cultures. One result has ambiguous effects. The cost of nickel sulfate sourced from nodules would be 47% less than from mines on land, reducing the cost of batteries and the green transition, but could reduce the number of non-artisanal jobs for nickel miners by impacting production or employment at mines higher on the cost curve.

Paulikas et al, Where Should Metals for the Green Transition Come From? LCA white paper, February 2020

(3) Relatively low abundance and species richness on CCZ seafloor

The table shows that sourcing battery metals from nodules uses 325% more habitat area, 508,000 km2 of seafloor vs. 156,000 km2 of land (including 66,000 km2 of forests). Consequently, we sought to understand and compare the impacts on FFI’s main concern: biodiversity.

In the full analysis, contained in the attached report, we note that many factors confound such a comparison. These include differences in faunal size categories used by marine and terrestrial researchers and sampling methods (e.g, depths below surface), differences in sampling depths of soil or sediment in different studies, poor knowledge of the number of species present in habitats on land and on the abyssal seabed, high proportion of new-to-science, rare and cryptic species on and in abyssal sediments as well as the meso- and bathypelagic water column, relatively modest understanding of the role of bacteria (and other microbes)—particularly on the abyssal seafloor— and technical and financial difficulties of sampling deep ocean habitats.

Nevertheless, some conclusions were clear. The ocean probably contains only one-sixth the number of species that occur on land, and that number decreases exponentially with depth. It is not surprising that the CCZ seafloor contains far fewer species, lower abundance and less biomass compared to many land habitats impacted by mining today. Considering its relatively unchanging conditions of intense hydrostatic pressure (5,700–8,500 pounds per square inch at mining depth of 4,000–6,000 meters), low temperature (~1.5°C), perpetual darkness, and dependence on very limited food availability, it is remarkable that life exists there at all. Food is severely limited to the slow trickle of detritus from overlying waters and production by chemosynthetic microorganisms. The number of species is limited not only by those challenges, but also because the CCZ seafloor contains only a modest amount of physical and topographic habitat diversity and no vegetation. The many microhabitats and niches provided by dramatic terrestrial topography and the complex architecture and novel food sources (e.g. leaves, flowers, nectar, fruit, nuts etc.) from higher plants provide much greater opportunity for evolution and coevolution of species on land than on the abyssal seafloor.

(4) Support of FFI’s interest in sparing high-diversity land areas from being mined

The number of megafauna at risk from mining is greater on land, particularly since amphibians, reptiles, birds and mammals do not exist on the seafloor and fish are only sparsely represented compared to populations in fresh, estuarine, coastal and reef waters.

In fact, the leading terrestrial sources of battery metals are classified as megadiverse countries and are major repositories of terrestrial biodiversity (species richness) (see table below).

Data sources for Table 18: Butler (2016) for rainforests; (IUCN, n.d.) for freshwater fish; Minter, et al. (2004) for South African amphibians; Royal Botanical Gardens, 2019 for Chilean vascular plants.

Our research documented some of the terrestrial species at risk from mining copper, nickel, manganese and cobalt on land.  Animals included Dinagat-Caraga Tarsier (Indonesia), Indonesian Cockatoo, Visayan Tarictic Hornbill (Indonesia), Giant Golden-Crowned Fruit Bat (Indonesia), Orangutan, Tiger, Rhinoceros, and Elephant (Indonesia) 5 species of Salmon (Alaska USA) Jaguar (USA and Mexico), Snow Leopard (Mongolia), Menduriaco Glass Frog (Ecuador), and Condor Range Tree Frog (Ecuador). We did not evaluate the plant species at risk though the number could be substantial.

We know that FFI is concerned about such species, as exemplified in its 2018 leadership in bringing an end to illegal gold mining, with its accompanying poaching and forest destruction in Liberia’s Sapo National Park, helping to save one of West Africa’s last refuges for pygmy hippos, western chimpanzees, forest elephants and giant pangolins, among others.

(5) Unintended consequences of the moratorium as proposed

Most important, a moratorium of undefined length would deny the world an opportunity to save about 2% of its remaining carbon budget, an urgent concern in view of the IPCC warning that  that humanity must mitigate emissions of carbon dioxide and other heat-trapping gasses within  10 years to avoid serious climate-related consequences.

We foresee that overhauling oceanic governance systems and assembling all the oceanographic and biological information called for in the FFI report would require at least a decade, ensuring that polymetallic nodules could not provide their climatic benefits within the IPCC timeframe as well as their environmental, social and biodiversity benefits.

A moratorium of undefined length would also retard opportunities to gather the kinds of biological and ecological information called for in the FFI report. Countries, companies and contractors seeking to mine deep sea resources provide the majority of research platforms and funding necessary for performing the Environmental Impact Studies. Results of those studies must be made public and reviewed by the International Seabed Authority before it can decide whether to permit exploitation of the resource.

Critically, these studies will become the primary source of baseline information available about the CCZ seafloor, its overlying water column, and potential impacts of nodule collection on its fauna and microbial flora. Without support from leaseholders and contractors, it will be extremely difficult, if not impossible, to answer the questions and concerns raised in FFI’s 2020 report.

We appreciate the concept of ocean connectedness emphasized in the FFI report and encourage its continued exploration. The facts and calculations presented in our attached report strongly indicate that collection of nodules in the CCZ will not harm global ocean circulation, function, primary productivity or primary fisheries, and will have at most temporary effects on marine mammals and birds. Potential effects on midwater species will form part of planned Environmental Impact Studies, though knowledge will always remain incomplete. Obligate nodule dwelling fauna will be harmed or killed on all nodules collected, though some may remain on the 15% of nodules that the collector machines miss. Recovery of those populations will take millennia or longer. Damage to the megafauna, macrofauna and meiofauna populations of the seafloor will also require considerable time to recover, from years to decades or centuries, but with time and recolonization from unmined areas set aside by the ISA and individual contractors, they will.

Despite the local damage that nodule collection will incur, the fact that the entire CCZ represents only 0.001% of the global seabed—and that up to 50% may be protected from mining as Areas of Potential Environmental Interest established by the ISA as well as those established by leaseholders— suggests that the risk of any major effect on overall ocean function is very, very small.  The abundant metal supplies available from CCZ nodules are a critical resource, especially at this time of unprecedented population growth, urbanization, burgeoning middle class and increasing consumerism. Those trends, as well as the urgency of transitioning to a green, renewable economy are driving accelerating demand for metals. Our analysis indicates that the CCZ is sufficiently rich in metals that the manganese, copper, nickel and cobalt needed to electrify the world’s automobile fleet can be obtained from only one-half of its total area. Therefore, it should be possible to preserve the other half in perpetuity, as part of the ‘half-earth’ movement (Wilson 2016), a philosophy which we strongly endorse.

We recommend that any nodule collection that occurs in the CCZ be done in the spirit of the FFI report, in accord with the report’s recommendations to the extent reasonably possible and with adequate monitoring and evaluation as the report describes.

Rather than simply enumerating the potential risks of deep-sea mining and calling for a moratorium until all raised issues are resolved, we believe that FFI needs to consider a much broader perspective: by weighing the risks of deep-sea mining against the risks to climate change, human health and terrestrial biodiversity that would occur if some deep-sea mining, especially collection of polymetallic nodules, did not occur.


Dr. Steven K. Katona

Advisory Board Member, Ocean Health Index, Conservation International

Emeritus President, College of the Atlantic

Dr. Laurence P. Maiden

Senior Science Advisor, Woods Hole Oceanographic Institution

Dr. Gregory S. Stone

Chief Ocean Scientist, The Metals Company


Butler, R. A. (2016, May 21). What are the world’s most biodiverse countries? Retrieved from Mongabay: https:// news.mongabay.com/2016/05/top-10-biodiversecountries/; also https://rainforests.mongabay.com

Harvey, C. and N. Gronewald. 2019. CO2 emissions will break another record in 2019. Scientific American E&E News. December 4, 2019.

IPCC. 2018. Summary for Policymakers of IPCC Special Report on Global Warming of 1.5°C approved by governments. October 8, 2018. Retrieved from https://www.ipcc. ch/2018/10/08/summary-for-policymakers-of-ipccspecial-report-on-global-warming-of-1-5c-approvedby-governments/

IUCN. (n.d.). Freshwater Fish Diversity. Retrieved from IUCN Freshwater Fish Specialist Group: https://www. iucnffsg.org/freshwaterfishes/freshwater-fish-diversity

Minter, L. R., Burger, M., Harrison, J. A., Braack, H. H., Bishop, P. J., & Kloepfer, D. (Eds.). (2004). Atlas and Red Data Book of the Frogs of South Africa, Lesotho and Swaziland. Washington, D.C.: SI/MAB Series #9, Smithsonian Institution. Retrieved from https:// www.researchgate.net/profile/Marius_Burger/ publication/48378776_Atlas_and_Red_Data_Book_of_the_Frogs_of_South_Africa_Lesotho_and_Swaziland/links/56e4139508ae98445c1eef2c.pdf

Royal Botanical Gardens. (2019). The Endemic Plants of Chile – an Annotated Checklist. Royal Botanic Gardens. Retrieved from https://chileanendemics.rbge.org.uk

Wilson, E. O. (2016). Half-Earth: Our Planet’s Fight for Life. W. W. Norton.

[1] ‘Cradle to gate’ analyzes the impacts of all activities beginning with resource extraction from the earth (cradle), and including transportation, refining, processing and fabrication until the material leaves the factory gate. ‘Cradle to grave’ further includes impacts of transportation to the material’s site of use in a product, as well as impacts of the product’s use, maintenance and disposal, reuse or recycling. Cradle to gate is the most appropriate method for comparing impacts of metals produced from different sources and intended for many possible uses.

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