Image credits: Linda Xu

Deep-Sea Mining: Alternative to Onshore Deposits

By Karin Dilge | Wed, 06/29/2022 - 17:21

In the last couple of years, talks about deep-sea mining have emerged around metals like gold, silver and copper. The breadth of mineral wealth under the ocean is still unknown but deep-sea mining could shift the balance between metal demand and supply with new discoveries of metal deposits. Nevertheless, the question of sustainability arises when thinking about the impact it could have on the marine ecosystem.

The deep seabed starts at depths greater than 200m and represents about two-thirds of the total seafloor. According to Capital, the surge in deep-sea mining matches the rise of battery metals and electric vehicles (EVs). Metals such as lithium, cobalt, nickel and other rare earth minerals can be found in abundance on the ocean seabed. However, due to expensive specialized equipment, special permits and licenses, many companies are discouraged from exploring these depths further.

A key attraction of ocean mining is that ores recovered from the seabed have up to 99 percent usable metals while terrestrial nodules have less than 20 percent, says Lahiri. A report by National Geographic shows that the ocean holds about US$150 trillion in gold. Furthermore, the World Bank estimates that cobalt production needs to increase by 450 percent between 2018 and 2050 to fuel the green transition, keep global temperature goals below 2°C and to meet the growing demand for battery metals. Accessing seabed resources would be key to addressing this demand as the ocean floor is estimated to hold approximately 1 billion tons of cobalt, according to an International Seabed Authority (ISA) report, an international body responsible of setting regulations governing seabed mining in areas outside national jurisdiction. Meanwhile, the US Geological Survey informed that terrestrial cobalt deposits amount to about 25 million tons.

Around 226 million tons of copper also lie on the seabed, which is 25 percent of the amount found on land. ISA has estimated that there could be 21 billion tons of polymetallic nodules between Hawaii and Mexico, holding 6 billion tons of manganese, 234 million tons of copper, 270 million tons of nickel and 46 tons of cobalt.

Some advocates of deep-sea mining argue that the process is less harmful than terrestrial mining as no people have to be displaced. In addition, it eliminates the need to destroy mountains, glaciers, deserts, surrounding land and communities. Nevertheless, the deep sea is home to ecosystems found nowhere else and provides a habitat to a multitude of species that according to scientists have not yet been discovered. It could take decades to understand the marine life of the deep ocean floor and its role in the global ecosystems. Even experts do not have the knowledge needed to ascertain how damaging seabed mining could be to the environment or its implications on the health of the broader ocean.

The G7 has met to agree on strict environmental controls on deep-sea mining and consent that only mining projects that do not seriously harm the marine environment could be approved. "We determined that if there is deep-sea mining at all, it should only happen following the strictest environmental standards," Germany's Minister of the Environment, Steffi Lemke, said during a news conference after a meeting of G7 ministers in Berlin.

Beyond permits and environmental concerns, the economic viability of seabed mining is still up for debate. In economic terms, long-term demand for critical minerals is uncertain as it depends on the evolution of technology. Plus, emerging innovations like battery technologies require fewer critical minerals, while circular economic models based on recycling indicate the possibility of a green transition without the need to mine the seabed, says New Security Beat.  

The most direct impact on the seabed environment would be the loss of biodiversity, light and noise pollution. “Mining impacts can spread over hundreds of thousands of square kilometers of the ocean, devastating fragile marine fauna, damaging important habitat and discharging harmful wastes. Especially worrisome, deep-sea mining could stir up seafloor carbon sediments, releasing CO2 that could exacerbate ocean acidification and add to climate warming. These operations could also conflict with established environmental and economic assets including fisheries, marine protected areas, shipping lanes and submarine cables and telecom terminals,” informs New Security Beat.  

Over the past 25 years, most geological knowledge related to the seabed has come from the exploration projects authorized by ISA. This research facilitates the identification of the best measures to protect the marine environment today and in the future. According to, ISA will begin issuing commercial licenses for deep-sea mining starting in 2025-2026.

“Mining should not occur unless subject to adequate regulations, founded on robust scientific data, to ensure the effective protection of the marine environment, however long that may take to achieve,” states an article on The Pew Charitable Trusts’ seabed mining project.


The data used in this article was sourced from:  
MBN, Reuters, National Geographic,,, PEW, NewSecurityBeat, Scientific American,, IUCN, Science Direct
Photo by:   Linda Xu
Karin Dilge Karin Dilge Journalist and Industry Analyst