‘More than the entire global defence budget’: new report shows that trying to fix the permanent damage deep sea mining would cause is so costly no one could afford it

Deep Sea Mining

Environmental damage due to deep sea mining would dwarf that of terrestrial mining in terms of km3 impacted, new Planet Tracker analysis shows.

  • Large-scale attempts to restore deep sea ecosystems would cost trillions: neither governments nor companies could pay for it
  • Planet Tracker calls on financial institutions to support a moratorium on deep sea mining worldwide


London, 29 June 2023: A new report from Planet Tracker, The Sky High Cost of Deep Sea Mining, has found that trying to restore the permanent damage to biodiversity caused by deep sea mining  would cost so much that no one could afford to pay for it.

While the likelihood of success for deep sea restoration is low, its cost is so high that it would be impossible for companies to pay for it and operate at a profit. Attempts to restore these ecosystems by replacing polymetallic nodules – key for marine life – with artificial clay nodules would cost USD 5.5-5.7 million per km2, more than the predicted company revenues of USD 4.4 million per km2. An area the size of Mongolia (1.5 million of km2, or more than 20 times the area mined on land) could be mined in international waters if no moratorium is decided.

Moreover, Planet Tracker calculated that the Environmental Compensation Fund developed by the International Seabed Authority (the UN-backed seabed regulator) cannot be sufficiently capitalised to cover the cost of restoration either. Restoring just 30% of deep sea mining concessions in international waters would likely cost more than the entire global defence budget.

Biodiversity impacts are a key concern for deep sea mining, and the report estimates that the total biosphere impacted by nodule mining in abyssal plains in international waters alone would be up to 25–75 million km3, more than the volume of all freshwater in the world, including ice and snow. Over half of species in the Pacific abyssal plain, where significant mining could occur, depend on these nodules for their survival. 

In comparison, the biosphere impacted by the mining of minerals critical for the energy transition on land is unlikely to be larger than 1 to 10 million km3.

Planet Tracker argues that the environmental damage expected from deep sea mining is not aligned with intergovernmental and national policy agendas which aim to halt biodiversity loss and promote nature restoration, as well as recent treaties to protect ocean life

In addition to these significant effects on biodiversity, the report argues that significant deep sea mining is unlikely to replace demand for land-based mining, calling the claim of proponents that it represents an ‘environmentally friendly alternative’ into question. 

François Mosnier, Head of the Oceans programme at Planet Tracker, comments: “There are many false solutions to the climate crisis, but deep sea mining is one that can still be stopped. More than 700 scientists have warned us that if it were to go ahead, it could pose irreversible risks to nature and climate on multi-generational timescale. Crucially, this environmental damage would not replace but add on to the harm caused by terrestrial mining, and we found that its scale would be truly mind-boggling. 

“We call on financial institutions to join others in supporting a moratorium on deep sea mining: the cost of attempting to fix this entirely avoidable mistake would be so high it could derail the much needed investments needed to tackle the climate and nature crisis. A moratorium is crucial and achievable.”

The Sky High cost of Deep Sea Mining can be downloaded in full here.



For more information please contact:

Josh Hoppen, ESG Communications | t: +34 6122 87264 | josh@esgcomms.com