Photo: Seafloor Nodules

Supporters of deep-sea mining (DSM) claim a “solution” to global warming is mining the metals coveted for green technologies (e.g., copper, nickel, and cobalt needed for electronic vehicles) from the deep sea.

These metals are found on the ocean floor at depths of 2.5 to 3.5 miles in the form of polymetallic nodules. These potato-sized rocks are comprised of layers of precious metals that build up around marine debris, such as shell fragments.

The nodules form extremely slowly, at an estimated rate of 2-15 millimeters per million years. Thus, the nodules can be tens to hundreds of millions of years old.

What DSM proponents blithely ignore, is the potentially catastrophic ecological damage that mining will wreak upon the environment because of the indiscriminate and aggressive process used to retrieve these nodules.

DSM involves the use of enormous mining vehicles weighing 25-40 tons that crawl along the ocean floor scraping off the top layer of the seabed – a process comparable to strip mining on land.

The nodules – along with surrounding sediment and unfortunate marine life – are sucked into a giant tube and pumped to a surface ship. The nodules are extracted from the slurry, and then the excess water and sediments (post-extraction wastewater) are pumped back into the ocean through another tube.

This wastewater forms sediment “plumes” that can spread up to 900 miles in multiple directions from the mining site and contain metals and other toxins that harm all exposed marine life.

Mining companies are especially interested in an area of the Pacific Ocean known as the Clarion-Clipperton Zone (CCZ), just 500 miles southeast of Hawaiʻi Island.

According to the Ocean Foundation, a simulation of seabed mining was conducted off the coast of Peru in the 1980s and when the site was revisited in 2015 some 26 years later, it showed no evidence of recovery. This suggests that the destructive impact of DSM is permanent.

Our dependence on healthy oceans for our very lives and for the lives of future generations cannot be overstated. And damage to one part of the ocean affects the whole; the world’s oceans are one interconnected body of water.

The world consumes about 176 billion tons of seafood every year. And 70% of the oxygen we breathe is produced by photosynthesizing organisms, such as phytoplankton, that live in the ocean. That is more than twice the oxygen produced by tropical rainforests.

Thus, the ocean itself plays a critical role in slowing climate change.

To date, more than 800 marine scientists and policy experts have signed a statement calling for a pause on deep-sea mining saying it would place considerable stress on already threatened marine ecosystems. There are more than 120 organizations around the world working to protect the deep ocean. In addition, 25 countries already have moratorium, pause, or ban positions on DSM, as have companies such as BMW, Volvo, Samsung and Google.

Recent reports indicate that electric vehicle battery chemistry is moving away from metals like cobalt and nickel towards metals like lithium – which is not found in relevant quantities in the deep sea.

The International Seabed Authority (ISA), an arm of the United Nations, is made up of 169 countries, all of whom signed and ratified the UN’s Convention on the Law of the Sea which entered into force in 1994.

It is the ISA that will decide the future of DSM.

A bill recently passed by the Hawaiʻi State Legislature and awaiting Gov. Josh Green’s signature would ban DSM in Hawaiian waters. Once the bill becomes law, Hawaiʻi will join California, Oregon and Washington State, all of whom have bans on DSM in their waters. This is important because some areas of interest for mining in the CCZ are within 260 nautical miles of Hawaiʻi.