Niels Hulsbosch is a postdoctoral researcher in ore geology at the Department of Earth and Environmental Sciences at the KU Leuven. Manuel Sintubin is professor of geodynamics at the Department of Earth and Environmental Sciences at the KU Leuven. Philippe Muchez is professor of in ore geology at the Department of Earth and Environmental Sciences at the KU Leuven. The deep sea is strewn with rich metal deposits. It is no surprise that national governments and mining companies have these metal deposits in their sights. The Belgian government also supports explorations of these deep-sea deposits. Manganese nodules on the deep sea floor - at a depth of 4000 to 6000 m - have been attracting particular attention. These nodules primarily consist of iron and manganese hydroxides, but also contain a variety of rare metals, in particular cobalt. Cobalt is such a fundamental - and currently irreplaceable - element in our transition to a sustainable world that it comes as no surprise that the European Commission considers it to be one of the 27 critical metals and raw materials. Indeed, the main application of cobalt (42%) is in high-grade batteries, which are vital for the development of low carbon energy technologies. The reserves of cobalt in the deep sea are estimated to be many times greater than the known reserves on land. As such, deep-sea mining opens up the prospect of ensuring a supply of this critical metal for future needs. As the prospects for deep-sea mining become increasingly realistic, there is also growing resistance from environmental organisations. In the first instance, they invoke the precautionary principle, and question the utility of this additional source of primary raw materials in the context of a well-functioning circular economy. The Bond Beter Leefmilieu (Society for a Better Living Environment) recently advocated for a cessation of all financial or other support for deep-sea mining from the Belgian government. But is now the time to stand on the sidelines, just when the framework is being drawn up at the international level in which deep-sea mining may be organised in the future? It is unreasonable to think that a global society no longer needs primary raw materials. In this early test phase, there are indeed still many questions surrounding deep-sea mining, from its technical feasibility to its economic viability. But the major unknown factor is clearly estimating the risks associated with deep-sea mining. Deep-sea mining will undoubtedly have a significant impact on the fauna and flora of the deep sea floor, of which we currently know so little. In this respect, we definitely share the great concern of environmental organisations. Marine biological research on these vulnerable ecosystems at potential exploitation sites should precede each test phase, in order to assess not only the impact, but also the potential for regenerating the ecosystem. However, it is unreasonable to believe that a global society, with an exponentially growing world population and a steady increase in prosperity, no longer needs primary raw materials, certainly in the short term, but also in the medium to long term. Indeed, recycling secondary raw materials after their use - the core of a circular economy - is still in its infancy. The recycling potential of critical metals, such as cobalt, at the end of their life cycle is still low (~35% for cobalt according to the European Union). The supply of various secondary critical raw materials is also currently too limited, since they are incorporated into devices with an increasingly longer life span. The contribution of secondary raw materials will still be a long way off from meeting the growing demand, meaning that we will need to use primary raw materials. In addition, the environmental impact of inland mining is growing, especially as rising metal prices and more efficient mining and extraction technologies have made it economically viable to extract large scale, but low grade, deposits. If deep-sea mining becomes technically and economically viable at the international level, it will not be possible to stop it. We should not be naive either. If deep-sea mining becomes technically and economically viable at the international level, it will not be possible to stop it. As such, we should not miss the opportunity to play an active role in this initial phase of research into the exploration of deep-sea deposits. Research programmes driven by a symbiosis between universities, research institutes, businesses and governments should enable us to acquire relevant geological, marine biological and mining knowledge as quickly as possible. This research should ensure a sound scientific basis for developing robust environmental, social and institutional regulations for evaluating, monitoring and regulating deep-sea mining in the future. We need to work together to create a culture of responsible governance and management of deep-sea deposits, with the ultimate aim of minimising the environmental impact of this new industry, which could help supply the critical raw materials for a high-tech, sustainable society. Abandoning all involvement in the development of deep-sea mining now may lead to irresponsible and unregulated exploitation in the future, without any regard for the environmental impact. This is definitely not the time to stand on the sidelines. In this respect, Belgium has the wherewithal to play a pioneering role in this initial, but also crucial, phase, with extensive scientific expertise at universities and research institutes, and also global players in the field of both marine extraction and the recycling of critical raw materials. Abandoning all involvement in the development of deep-sea mining now may lead to irresponsible and unregulated exploitation in the future, without any regard for the environmental impact, possible unforeseen price fluctuations and market disruption, but also a possible brain drain of expertise from our country. The ultimate decision to turn our attention to deep-sea mining as one of the methods of producing primary raw materials will require a careful assessment of all mining-related technical, environmental, economic and social impacts, in the context of internationally agreed sustainability goals. Let us therefore play a leading role in this process, and leave an indelible mark on the international standards to which deep-sea mining must adhere. A responsible, highly-regulated and monitored extraction of primary raw materials in the deep sea can be complementary to the extraction of secondary critical raw materials in the context of a circular economy. If the Belgian government were to withdraw from this early stage of a process that will take years, even decades, it would clearly send out the wrong signal. https://www.demorgen.be/opinie/laten-we-het-voortouw-nemen-bij-diepzeemijnbouw-be7dd5fa/