The increased demand for valuable minerals and metals (such as manganese, cobalt, and nickel) coincides with the increased demand for technology and new infrastructures. Land based mining allows for the extraction of these elements; however, it results in vast environmental damage and greenhouse gas emissions, with the mining industry generating between 1.9 and 5.1 gigatons of carbon dioxide annually. New technology has allowed for the possibilities of seabed mining to be explored and utilised to keep up with the demand for these rare elements, whilst also reducing land damage.  

The recovery of minerals from the seabed by underwater mining takes place on the ocean floor, often near active (or extinct) hydrothermal events. It can also occur around vast areas of polymetallic nodules 1,400-3,700 metres below the ocean surface. Minerals obtained include manganese nodules for technological productions, cobalt-rich crust, and sulphide deposits containing cobalt, zinc, copper, silver, and gold. 

Hydraulic pumps are used to extract minerals by lifting the materials to surface vessels or platforms. A bucket system is another method of extraction used to collect minerals. Minerals collected are often used to aid the energy transition towards cleaner energy sources (including electric vehicles). Whilst this reduces the need for land-based mining and reduces the environmental impact on the land, it has many implications for the functioning of marine life and often results in habitat destruction. 

Marine ecosystems are very vulnerable to change, especially at such great depths. This means that small interferences can cascade into catastrophic events. Vibrations and sound waves from the equipment disturb animals; it impacts their communication, navigation, and feeding. In turn, this could then impact breeding, food chains, and migration patterns. Furthermore, sediment plumes produced from this equipment can spread over large areas, smothering habitats, reduce light penetration, impact filter feeding organisms, and damage small environments. Toxic chemicals released into the water, and harmful elements contained in minerals such as heavy metals, will also greatly impact marine ecosystems. 

Norway may become the first country to allow for commercial deep-sea mining, with the majority of parliament approving the governmental proposal to open a vast ocean area for commercial-scale deep-sea mining. They aim to explore remote mid-Atlantic ridges for minerals such as copper, cobalt, and other rare Earth elements. In doing so, they would be able to reduce their dependence on China for mineral supply.  Whilst this is economically beneficial, there will be a multitude of both known and unknown environmental impacts. 

Currently, the UK supports a moratorium on deep sea mining to protect ecosystems and to advocate for strong environmental regulations before granting exploitation licences.

Polymetallic nodules containing valuable metals are common in the Pacific Ocean, and the international seabed authority has granted 19 exploration licences for the Clarion Clipperton Zone (CCZ) in the Pacific Ocean. This area covers around 4.5 million squared kilometres between Hawaii and Mexico, with the International Seabed Authority (ISA) regulating mining and emphasising environmental protection of the CCZ. Remotely operated vehicles will be used here, with a deep-water pipe used to transport nodules to a surface vessel (where cleaning and processing occurs), after which rinsed sediments are returned to the ocean. 

The CCZ comes with many benefits, including job creation, aiding the energy transition to clean technologies through minerals, and encouraging scientific insight into deep sea ecosystems. Whilst this zone will be monitored, the excessive use of seabed mining will result in many ecologically damaging impacts. The return of sediments does not occur in the location from which it was extracted from, but another area. This can smother habitats. Furthermore, nodules are often the only anchor for megafauna due to barren sea floors, and this extraction results in an unstable ecosystem, impacting biodiversity. 

Whilst seabed mining is economically beneficial, it has many negative ecological impacts. Technological advancements have allowed for this industry to progress, however, if technological advancements were redirected to more sustainable alternatives, this would be significantly better for the environment, whilst also encouraging new jobs and economic progress. Some alternatives include reducing the demand for raw materials through better product design, reuse, repairing, and recycling. A focus on recovering valuable materials from electronic waste instead of deep-sea mining would decrease the demand for raw materials. Structural changes in consumption patterns and the development of batteries using widely available metals to avoid this extraction would reduce the reliance on deep-sea mining. With the inevitable progress of sea-bed mining, investment into precision technologies should be prioritised, including AI guided robotic ‘arms’ to remove modules without disturbing seabed ecosystems, and the use of underwater drones to minimise impact. 

To conclude, sea-bed mining is an economically beneficial way of extracting rare elements and keeping up with the increasing demand, however, it results in many negative environmental impacts. Greater technological advancements are needed to reduce its ecological impacts. Prioritising sustainable alternatives and a focus on circular economy practices would aid in this, especially as many regions that were identified for seabed mining are also recognized to be vulnerable marine ecosystems.

By Isabel James