Deep-sea mining would cause more ocean damage than climate change combined, DFO scientist warns

Deep-sea mining will cause more damage to the oceans than climate change, pollution, ocean acidification, global warming and oil spills combined, said Cherisse Du Preez, head of deepwater ecology at Fisheries and Oceans Canada.

Life in the deep sea moves on geological time scales. Sponges form living reefs that are 10,000 years old. Sharks can live to 600 years old, and rockfish more than 200 years. Deep-sea creatures will never adapt to or outrun the effects of mining, Du Preez said, adding that "there are lineages in the deep sea that have survived all of Earth's mass extinctions, except potentially what we're about to do."

Mining threatens the ocean through two major mechanisms. First, machines obliterate everything on the seafloor to suck up precious metals. Second, the operation dumps almost everything back into the ocean as plumes of toxic sediment containing radioactive material and heavy metals, suffocating and poisoning animals.

Most precious metals in the ocean are found in and around seamounts—underwater volcanoes and mountains. Seamounts are often extremely steep, functioning as underwater oases for marine animals that cannot simply swim to another home. Ninety-five per cent of all habitable land for life on Earth exists in the deep sea; rainforests, mountains, savannahs and plains occupy just five per cent of Earth's habitable land.

The Vancouver-based Metals Co. has been working with the Trump administration to eventually mine the Clarion-Clipperton zone, located in waters between Mexico and Hawaii. The U.S. Bureau of Ocean Energy Management is also considering approving mining on seamounts on the Canada-Alaska border.

As a scientist, Du Preez said it is her job to ensure decision-makers understand the full consequences. "If more people realized what's at stake and what is about to be lost, there's no way they would allow it," she said.