Deep sea mining – what you need to know

Deep sea mining is the practice of mining metals and minerals from the seabed. Among many other risks to people and biodiversity, it would damage the oceans beyond repair, threatening their ability to help fight climate change. Here’s everything you need to know.


What is deep sea mining?

A hand holding a large potato-sized rock which has rough bits and smooth bits to indicate its makeup of different elements.

A manganese nodule. Polymetallic nodules that have formed on the seafloor contain valuable metals. One of the largest deposits of manganese nodules is found in the Clarion Clipperton Zone in the deep Pacific ocean between 4000 and 6000 meters below sea level. © Wolfram Kastl / Greenpeace

Deep sea mining is the practice of removing metals and minerals from the ocean’s seabed. Thousands of metres below the surface, deposits of these metals and minerals like manganese, nickel and cobalt have built up on the seafloor into potato-sized nodules over millions of years.

To mine these metals, gigantic machines weighing more than a blue whale would scoop deposits from the deep ocean floor. They’d then pump the mined material up to a ship through up to several kilometres of tubing. Sand, seawater and other mineral waste would then be pumped back into the water.

Deep sea mining is a very new industry. Apart from a few small tests, no commercial mining has happened yet. But the companies involved are preparing to start full-scale production.

What are the problems with deep sea mining?

Like mining on land, deep sea mining is extremely destructive. But mining the ocean floor is risky for so many reasons.

The full environmental impacts of deep seabed mining are hard to predict. But they’re likely to be highly damaging, both within and beyond the areas being mined.

The oceans are facing more pressures now than at any time in human history, and are threatened by overfishing and the climate crisis. Our oceans absorb and store carbon, and give more than three billion people their livelihoods.

Danger to habitats

The nodules containing the metal deposits have taken millions of years to form and are one of the keystones of deep sea life. When they are gone, they cannot be replaced; nor can the ecosystems that thrive around them. This would cause disruption all the way up the food chain that Pacific communities – and all of us – rely on.

Mining these deposits would destroy biodiversity and habitats which have far reaching benefits to all life on Earth that aren’t fully understood. The deep ocean is a vast reservoir of biodiversity, from glowing sharks to armoured snails, with new species being discovered every year.

A pinky-purple octopus with its eyes closed and legs curled up around its head, nestled among pale yellow corals and rocks and other jelly-like spiked creatures.
A spiky translucent creature with long tendrils emerging from its jellyfish like body, almost on the sea floor with inky blue water around

A giant Pacific octopus rests among anenomes and sponges during undersea research of Pribilof Canyon in the Bering Sea, Northern Pacific Ocean.
And a newly-discovered species, a giant sea anenome, scoots along the seabed at 4,100 metres deep in the Clarion Clipperton Zone in the Pacific. The anenome lives on sponge stalks attached to polymetallic nodules.

Impacts on the climate

The deep ocean is vital in the fight against climate change. It absorbs and stores over 90% of the excess heat and nearly 40% of the carbon dioxide generated by humanity. Risking this delicate system during a climate emergency could have irreversible impacts on the climate.

Underwater noise

The noise from deep sea mining will travel far, and be extremely disruptive to marine mammals that use sound as a primary means of underwater communication and sensing.

Plumes of pollution

Deep sea mining companies haven’t proven that they can do it without harming the environment. They’ve got a huge piece of machinery stuck on the deep sea floor. Their tests are already creating plumes of pollution in the Pacific. These plumes can spread for many, many miles – potentially harming all sorts of ocean life.

A side view of a large red ship filling the whole frame with a smaller vehicle that looks like a tank being lifted out of the ocean below. There is a large patch of yellow sediment visible in the dark blue water just below the machinery

Sediment is seen on the surface coming from a nodule collector as it is recovered from the Pacific Ocean. © Marten van Dijl / Greenpeace

Who would be affected by deep sea mining?

Vulnerable coastal communities, especially in the Global South, will pay the highest price. Peer-reviewed science shows that deep sea mining is almost certain to cause lasting damage to deep sea ecosystems. This means potentially severe impacts on countries and communities that depend on the Pacific Ocean.

Deep sea mining could harm the fish populations that provide food and livelihoods for many Indigenous Pacific communities. These communities have profound cultural and spiritual ties with the sea.

Opposition to deep sea mining

International opposition to the deep sea mining industry continues to grow.

  • Businesses including car companies, Google, Samsung and Ecotricity have committed to avoid ocean-mined minerals.
  • Many governments are now calling for a permanent or temporary ban, including France, Spain, Germany and New Zealand. The UK is calling for a temporary ban.
  • Scientists around the world have also opposed the industry. More than 700 from 44 countries signatories on an open call to pause deep sea mining.

A growing list of countries – including Germany, France, Spain, Chile, New Zealand and several Pacific Island nations – think deep sea mining is risky for marine life. They are proposing a pause or a ban on issuing licences. In October 2023 the UK joined these governments to support a global moratorium. The UK government should now go further and support a permanent ban.

Who is involved?

The secretive deep sea mining industry is run by mining companies headquartered in the Global North, in partnership with governments. Mining companies, like The Metals Company, appear to be pushing countries to help them open up a new frontier for mining the ocean.

Countries can sponsor companies’ applications for exploration and mining contracts to the International Seabed Authority, or ISA.

The ISA was founded in 1994 through the UN Convention on the Law of the Sea and is headquartered in Kingston, Jamaica. It makes the rules for deep sea mining, because the seabed is outside of countries’ national borders.

The ISA’s officials also seem to be pushing for companies to be allowed to start deep sea mining. This is despite the ISA’s mandate to protect the global oceans, and only allow mining to start if it can benefit humanity.

The UK government sponsors two exploration licences, both granted to UK Seabed Resources. These cover over 133,000 square kilometres (an area bigger than England). The UK’s licences cover a larger area than any other country, except China.

Why do companies want to mine the seabed?

Companies want to extract metals from the seabed to sell them to industries that need increasing amounts of manganese, cobalt, nickel and copper for one simple reason: to make a profit. To them, the sea is just another frontier to exploit for money.

Mining companies are saying they need to mine the seabed for the metals needed to make batteries for the energy transition away from fossil fuels. But mining one of the last untouched ecosystems on Earth will never be “green”.

And deep sea mined metals could be used in any industry. The US government, for example, has now decided that mining the seabed will help secure metals to use in weaponry. Destroying the seabed and precious ocean life for materials to wage war is a new low.

Alternatives to deep sea mining for the energy transition

Deep sea mining companies have been trying to trick people into thinking that deep sea mining will be needed to supply the metals needed for renewable energy storage and electric car batteries.

But there are huge uncertainties about the amounts of metals that will ultimately be needed – especially if we minimise demand and significantly increase recycling and the use of recycled materials in batteries. Deep sea mining companies don’t want this, as it would make them unprofitable – so they’re predicting maximum demand for their products.

Here are three reasons deep sea mining isn’t necessary for the transition to electric vehicles:

  1. More and more, cities are seeing the benefits fewer private cars, whether electric or not. Accessible public transport, walking, cycling and more shared journeys makes cities more affordable, cleaner, safer and healthier. This will reduce demand for battery metals.
  2. Car companies are now using a new electric vehicle battery chemistry without cobalt and nickel – two of the metals proposed to be mined by deep sea mining. They could also make smaller, more efficient cars with smaller batteries.
  3. Improving recovery and recycling of battery materials (as the EU is requiring in a new law) means less need for new mining.

The only way to fairly transition away from fossil fuels is by reducing demands on our exhausted planet – not by drilling and digging some of the last untouched places on Earth.

Where is it happening?

Although test mining is underway, commercial deep sea mining is not yet allowed by international law. The International Seabed Authority has granted 31 contracts for exploration. These cover over 1.5 million km² – an area four times the size of Germany.

Most of these contracts cover exploration for deposits in the Clarion-Clipperton Zone (CCZ), an area in the Pacific Ocean across the equator, between Hawaii and México. The area is rich in potato-sized mineral deposits loaded with copper, nickel, manganese and other metals. They lie on the deep sea bed in huge fields.

A showing the locations of polymetallic nodules in the clarion clipperton zone. They're clustered densely together in colour coded blocks.

What are the rules for deep sea mining?

In July 2021, the government of Nauru announced intentions to begin deep sea mining, partnering with a Canadian company. The announcement triggered an obscure “two year rule” in international law meaning that by July 2023 mining can begin, with whatever rules are in place – or lack of them.

The International Seabed Authority (ISA), met in Jamaica to try to agree what those rules are. However, the growing opposition to deep sea mining, which included Greenpeace supporters, meant that no such rules could be agreed. In fact, such was the volume of opposition that the ISA has even agreed to discuss a moratorium at next year’s meeting!

This shows the power of our collective voice. The meeting at the ISA was supposed to be a formality. But thanks to everyone who spoke out, we’re now talking about applying the brakes, potentially forever.

We need to stop deep sea mining

This is a crucial moment. We need to stop profit-seeking companies from destroying the oceans and a crucial defence against climate change. We scored a huge win at the ISA in July, but we’re not out of the woods yet. It’s still possible that an application to exploit the ocean gets approved, although it would be difficult. And we haven’t yet secured a ban.

Imagine if we could go back in time and stop dangerous oil drilling. Stopping an industry before it has a chance to start will prevent further environmental and climate catastrophes.

Content note: the header image on this page is a still from a Greenpeace animation about deep sea mining, not a photo of a real deep-sea mining operation.