Standing on the brink of a problem so big that fifty years of research haven’t significantly advanced your understanding of its solution is subtly unsettling. That’s about where ocean science is at the moment. We still don’t fully understand what deep-sea mining will do to the ecosystems down there, and the industry is accelerating anyhow, according to a significant new review led by Professor Adrian Glover of the Natural History Museum. The review went through more than 200 published and unpublished reports spanning more than fifty years.
The Clarion-Clipperton Zone, an area of abyssal Pacific seafloor about the size of the continental United States, was the main subject of the review, which was published in Current Biology. Polymetallic nodules, which are fist-sized lumps of cobalt, nickel, copper, and manganese that have formed over millions of years at a rate slower than the growth of human fingernails, cover the seafloor at depths greater than three thousand meters. Governments and mining firms searching for the raw materials used in wind turbines and electric car batteries have found these nodules to be very appealing. In an odd turn of events, the green energy transition is increasing interest in one of Earth’s least understood environments.
After examining decades’ worth of experimental disturbance tests and biodiversity surveys, Glover’s team discovered that the harm caused by even the earliest mining trials has remained stubbornly persistent. Organisms that took centuries to establish themselves have been suffocated by sediment plumes that have settled over nearby seabeds as a result of test operations. The industry frequently draws attention to the gradual recolonization of some dominant animal groups. However, it is more difficult to read the larger picture. There is still no real answer to the deeper question of whether full-scale commercial extraction would actually cause species extinction rather than just local disruption.
Perhaps the more concerning situation is hydrothermal vents. These ecosystems rely on chemical energy that seeps from the seafloor to survive completely in the absence of sunlight. These vents are surrounded by dense colonies of shrimp, ghostly crabs, and human-arm-length tube worms in almost unbelievable arrangements. The same metals that mining companies seek are also deposited in the vents. Compared to the nodule data, there is much less research on how these communities would react to extraction, and what is known points to recovery timescales that are probably decades rather than years, if recovery occurs at all.
Reading the science gives the impression that the knowledge gap has evolved into a political convenience. Operating under a mandate that was never fully intended for the commercial pressures currently pressing it, the International Seabed Authority has awarded more than thirty exploration contracts throughout the deep seafloor. There are paper versions of the regulatory frameworks. It’s another matter entirely whether they’re prepared for what lies ahead.
It’s difficult to ignore how familiar this situation is. Industries have previously surpassed scientific consensus, sometimes with disastrous results and sometimes without. This is different because the deep sea takes longer to recover. Geological time governs the abyssal plains. There are still obvious scars on a section of seafloor that was disturbed in 1989 during the German DISturbance and reCOLonization experiment. After 35 years. There are still sediment trails. Naturally, the nodules have disappeared.
The fact that the minerals being targeted aren’t some kind of luxury good is what really complicates this situation. One could argue that they are essential to the energy systems on which the world is placing bets. The conflict between material urgency and ecological caution will not be resolved amicably. Science is open about its limitations. None of those two hundred reports address the question of whether the industry and its regulators will be equally honest.
