A ship at sea lowering mining equipment by a winch

Testing has previously begun ahead of possible deep seabed mining in the Pacific. Credit Marten van Dijl - Greenpeace

Scientists have called for a blanket worldwide moratorium on deep seabed mining – insisting the controversial emerging industry currently poses an “unjustifiable environmental risk”.

A team of interdisciplinary researchers from the University of Exeter have issued the urgent clarion call in order to protect the marine environment from potentially irreversible damage.

The researchers insist that the arguments put forward for deep sea mining fail to hold true from both an environmental and an economic geology perspective.

Crucially, they suggest that there is currently no coherent “net zero carbon” argument for the practice because the metals which deep sea mining could potentially source – including copper, nickel and cobalt,  which are urgently needed to build renewable energy technology and thereby help decarbonise our society – remain widespread on land.

They note that whilst on-land mining is also, by definition, environmentally destructive it is a relatively mature “tried and tested” technology. In contrast, deep sea mining is highly novel and the environmental risk of such activity therefore remains largely unknown and could be extremely severe – and irreversible on human timescales.

The researchers also point to our immediate future where on-land mining must be urgently scaled up, to source metals needed to tackle the Climate Emergency, and then ultimately be displaced with a fully circular “recycle and reuse” economy. 

Deep sea mining could in theory contribute towards this vision, however, the researchers argue that the environmental risks which it currently poses are simply too great – it should not be undertaken until such risks are proven beyond doubt to be acceptable.

They therefore call a worldwide moratorium on deep sea mining to allow time to ensure all potential impacts, and alternatives, are explored fully.

Dr Rich Crane, a co-author from the University of Exeter, said: “We currently face unprecedented demand for metals to sustain modern society and tackle the Climate Emergency. Deep sea mining could contribute towards solving this issue, but its environmental impacts will be widespread and remain unpredictable. It should therefore only be allowed once it has been proven beyond doubt that such risks are acceptable. That day may never come but until then precaution must prevail. We urge all nations to join the moratorium on deep sea mining.”

Dr Kate Littler, a co-author from the University of Exeter, said: “The deep sea is the largest biome on Earth, home to unique and vulnerable organisms, many of which are still unknown to science. Human activity continues to severely disturb the biology and biogeochemistry of the global ocean through fishing, shipping, and pollution; it is imperative we take the upmost care before deciding to decimate the deep sea for transient economic returns.”

Professor James Scourse, a co-author from the University of Exeter and part of the Convex Seascape Survey, an ambitious five-year project examining ocean carbon storage, said: “If allowed to go ahead, deep-sea mining would potentially result in global impacts that transcend national jurisdictions. Financial rewards for a few individuals and companies would be at the expense of the natural ecosystem and the majority of humanity. For once, we have an opportunity to prevent catastrophic exploitation and to support responsible onshore mining to the benefit of local communities.”

The call was published in Nature Sustainability on Tuesday, April 16th 2024.