Deep-Sea Mining: The key to sustainable energy?

The overwhelming support for the Paris Agreement implies the existence (at least on paper) of a consensus among states that climate change is an issue, and for mitigating its worst effects, the temperature must not be allowed to rise further. As of 2021, most of the greenhouse gases are emitted from the electricity and heat sector. Specifically, energy production generated 37,635.61 MtCO2e that year, while all other sectors combined together generated only 12,145.69 MtCO2e (Source: Climate Watch). Thus, it is evident that greenhouse gas emissions for energy production need to be cut down. 

The movement to reduce emissions from the energy sector is happening in the form of a transition towards renewable energy sources, such as solar, wind and hydropower. For instance, the Netherlands aims to generate 70% of all its electricity sustainably by 2030, and by 2050 to have almost all energy supplies come from sustainable sources and be CO2 neutral (Source: Netherlands Enterprise Agency). Let us focus on where this renewable energy (not only for the Netherlands, but also on a global scale) is or will be coming from. 

Hydropower, solar and wind are the leading renewable energy sources. In 2023, the global electrical energy production from hydropower amassed 4240 TWh, while 2325 TWh and 1642 TWh of the global electricity was generated from wind and solar energy respectively (Source: Our World in Data). While contributions from wind and solar power may not seem like much, if historic electricity generation is considered, then wind and solar power are growing rapidly.  

Questioning the sustainability of wind and solar energy may seem redundant at best and an unnecessary hindrance that will take us back by fifty years at worst. Solar and wind energy have small carbon footprints, almost negligible in the face of thermal power plants. In fact, most of the emissions produced during the production of solar panels and windmills are offset by “clean” energy production within the first few years of operation. However, it should be kept in mind that despite its relevance, emissions are not the only indicator of sustainability and environmental friendliness. A hidden side of wind and solar energy relates to the production of equipment needed for generating electricity. Building solar panels and wind turbines requires critical minerals, the extraction of which should spark a second thought. The problems with mining copper, lithium, nickel and cobalt – metals critical for the renewable energy transition – may not appear to be much in the face of the global climate crisis, but they do exist and thus bear consideration. 

First of all, critical minerals are unevenly distributed across the world. They tend to localize within “hotspots”. Countries with higher quantities of these minerals can, through underground reserves, control the world’s energy supply. Traditionally energy-independent countries may now have to depend on others, something they are most certainly not looking forward to. Secondly, as is the case for a myriad of resources, our planet is running out of precious metal and graphite reserves on land. The global demand for nickel, graphite and lithium is projected to increase by 20, 19 and 14 times, respectively, in 2024, as compared to 2020. A supply deficit of lithium is expected to hit during the upcoming decade. When it comes to nickel, a shortage already occurs globally as this article is being written. Minerals are needed; nevertheless, governments and energy producers either cannot access enough reserves or hesitate to rely on imported materials. A solution being widely touted is deep-sea mining. 

Deep-sea mining, as the name suggests, is the extraction of minerals from the ocean floor, hundreds or sometimes even thousands of miles below the surface. There, deposits of manganese, nickel and cobalt have built up for thousands of years, untouched by human hands (much like fossil fuels were untouched by humanity many, many years ago). With the discovery of new resources comes the question of its governance. The ocean floor, and by extension, deep-sea mining, is under the jurisdiction of the International Seabed Authority (ISA). The ISA is an intergovernmental body of 167 member states and the EU. It was established under the 1982 UN Convention on the Law of the Sea (the biggest legal framework protecting the oceans). The ISA has a two-pronged mission – protecting the ecosystem of the seabed, ocean floor and subsoil (of the oceans beyond national jurisdiction), and controlling the development of mineral related operations, such as deep-sea mining. Whether the same body should be responsible for managing resource exploitation and ecological protection is a subject of ongoing debate among professionals and lies beyond the scope of this article. 

As of 2024, the stance of the ISA on deep-sea mining remains enigmatic. However, this can change sooner than later – the ISA has until 2025 to finalize regulations dictating whether countries can pursue deep-sea mining in international waters, and if yes, how. This can be seen in the licenses issued. Currently, the ISA is yet to hand out any commercial-scale licenses for deep-sea mining. So far, only thirty-one exploratory licenses have been issued. This makes today the time to debate whether deep-sea mining is really the way to go forward, and in this debate, there are some points that must be kept in mind. 

First, how do we view the deep sea? Once thought to be barren and devoid of life, we now know this could not be further from the truth. The deep sea is the largest habitable space on Earth and is home to a dazzling array of life. To date, tens of thousands of species have been discovered here, with estimates stating there could be millions more. Consider the Clarion-Clipperton Zone (CCZ), for instance. Located in the Equatorial North Pacific Ocean between Hawaii and Mexico, the CCZ is as wide as the continental U.S., and home to trillions of polymetallic nodules of nickel, manganese, copper, zinc and cobalt. This makes it the ideal base for deep-sea mining. But that is not all the CCZ is home to. Over 5,000 species, entirely new to science, have recently been discovered here. A staggering new 219 taxa (families, genera and species), unseen before, have been found. Clearly, the absence of sunlight at the seabed does not make it devoid of life. Rather, there are diverse ecosystems here of which we know little to nothing. 

This is one of the biggest concerns related to deep-sea mining – how will it affect marine organisms? There is a very high likelihood that those organisms which are sessile or less mobile will be killed through direct contact with the heavy equipment necessary for deep-sea mining. The sediment plumes arising from this machinery could smother and suffocate nearby marine organisms. Warm mining wastewater could kill marine life through overheating and poisoning. Additionally, mining activities could affect the feeding and reproduction of deep-sea species by creating noise and light pollution in an environment that is naturally silent and dark. Noise pollution can negatively impact large megafauna like whales, further threatening populations already at risk due to anthropogenic activity. 

Ironically, the intensely sought-after polymetallic nodules are the home for many rare, long-lived, slowly reproducing deep sea species. The issue with being slow to reproduce is that such organisms are also slow to evolve and adapt to changes in environmental conditions. Deep-sea mining would not only render them homeless, but also dead. 

It is not only the local seabed which is at risk. Like many other environmental problems, the effects of deep-sea mining will be transboundary. According to the current project designs, the waste discharge from mining vessels could spread over large distances, maybe even kilometers away from the area being mined. This poses a threat to every ocean ecosystem within the radius. This mining waste could cause suffocation, damage to the respiratory apparatus and feeding structures and disrupted visual communication. And these are only the direct threats to organisms. Mining waste can further cause changes in the oxygen content, pH, temperature, as well as the presence of toxic substances in seawater. All these effects are at the very least undesirable for every environmentalist and most marine life. 

Marine life is not the only aspect at risk. Deep-sea mining can even affect the climate, and not in a beneficial manner. The ocean is the world’s largest carbon sink. While the process is not yet understood in its whole complexity, we do know that microscopic organisms play a key role by sequestering carbon in the deep sea. How will the loss of deep-sea biodiversity affect their carbon sequestration capabilities? More broadly, how will deep-sea mining affect an ecosystem as fragile as that of our oceans? 

The bottom line is that there is much yet to be revealed. Last time humanity attempted to exploit a resource in planetary amounts without understanding the full scale of its ramifications, we caused a global climate crisis and kickstarted a mass extinction event. 

References

1. Climate Watch https://www.climatewatchdata.org/
2. Netherlands Enterprise Agency https://english.rvo.nl/
3. Our World in Data https://ourworldindata.org/