In the first of our new feature series exploring controversial climate topics, Sci&Tech Editor Georgia Brooks explores the benefits and concerns surrounding deep sea mining, concluding that we should leave this fragile and little researched ecosystem alone.

Written by Georgia Brooks
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Deep sea mining, the process of extracting minerals from the ocean, below a depth of 200m, (which accounts for roughly two thirds of the seabed), holds the potential to rapidly accelerate our transition to net zero and renewable energy, and yet so little is known about this ecosystem that it will undoubtedly also cause harm, we just don’t know quite how much. 


The chance to transform our energy system?


Right at the bottom of the ocean, trillions of polymetallic nodules litter the sea bed, and these unprepossessing dark ‘lumps’ could hold the secret to the energy sector’s transition to renewables. Each nodule contains manganese, nickel, cobalt and copper, metals that are crucial to creating electric vehicles, wind turbines and solar panels, because of their use within batteries. They therefore could be the key to a much more rapid transition to net zero than we’re currently witnessing, as these materials are needed in abundance in order to create the tools we require to slow climate change. 

These ‘nodules’ hold the secret to the energy sector’s transition to renewables

This is in fact more than just a climate issue: human rights are also involved. Manganese, for example, is currently largely extracted in open pit mines, which not only are damaging to the environment as they often exist in deforested areas, but also have been linked to health issues in those living nearby. Similarly, cobalt mining in countries such as the DRC leads to a variety of health threats including overexposure to toxic chemicals and gases, but also to violence, accidents and corruption within the country and area. Deep sea mining could be an opportunity to clean up this industry, and reduce the myriad of dangers that are associated with it (both environmental and human), while also increasing the extraction of these invaluable metals to meet the increasing (and necessary) demand, hence fastforwarding the global energy transition. 

Deep sea mining could be an opportunity to clean up the incredibly harmful open pit mining industry


Or a recipe for disaster? 


On the other hand, many scientists are strongly against the idea of deep sea mining, fearing the extreme damage that it would cause to this little understood ecosystem. Digging, or even just researching, the seafloor would lead to alteration and probably destruction of habitats and hence habitat fragmentation and a loss of species. It is likely to create sediment plumes: suspended particles from the seabed that will disperse and could smother animals, harm filter-feeding and block visual communication. Just the process of having vessels, rigs and equipment will undoubtedly also disturb many species. In addition, these nodules that mining would remove in fact are the only hard materials in many areas at these depths and hence provide a vital habitat for creatures that cannot live on mud alone. Hence it is clear that despite the obvious potential that deep sea mining could have, there are many threats and risks associated, and in all probability, many more that we have no idea about. Many scientists, including David Attenborough, have called for a moratorium on all deep sea mining plans. 


So, what’s the verdict? 


With such a polarising and complex issue, it is hard to know what the best approach is. However, I believe that mining the deep sea would be incredibly destructive, and the fact that we know so little about this ecosystem just concerns me even more – humanity has made this mistake in the past, and I believe we should try our best not to repeat it, and hence leave this ecosystem undisturbed. The research and development that would be required to create a sustainable mining plan would take years, and I believe that these resources would be better put to use improving the legislation around mining on land that is already taking place (and is unlikely to stop in the near future), and towards developing batteries that require materials that are less damaging to extract (a process that is currently underway). 

Mining the deep sea would be incredibly destructive, and the fact that we know so little about this ecosystem makes it even more concerning


However, the pacific island of Nauru has partnered with a mining startup DeepGreen and activated a clause in the UN Convention on the Law on Sea – they feel that negotiations around the topic are going too slowly. The island state fears being overwhelmed by rising sea levels – this is a nation that will be directly affected, and wants to use its potential reserves to change this, although there is undoubtedly an economic motive involved as well. I, for one, really hope that the moratorium on deep sea mining goes ahead, but this is not a binary issue and the next year or so will be crucial to deciding the outcome on this issue, one way or another.


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