The deep sea must be protected, not plundered

The deep sea is mysterious and beautiful. 

At 1,000 meters, sunlight dissipates and blue turns to black. Temperatures hover near freezing. The pressure is crushing, like the inside of a trash compactor. The marine life is otherworldly. The seabed teems with corals older than written language, bacteria that feed on ammonia and sulfur, along with squid that measure 45 feet long. These pristine ecosystems could be home to 10 million unique species — most of which have yet to be discovered. 

But some seek to exploit the seabed, rather than explore it. 

Seamounts, trenches and volcanic vents contain vast troves of treasure: potato-sized nodules of manganese, nickel, cobalt, copper, lithium. These minerals are coveted by battery manufacturers eager to capitalize on a post-fossil-fuel future — and without swift action by the international community, companies could begin strip-mining the ocean floor this summer. Although the long-term impacts of seabed mining remain unclear, all available evidence suggests it would be an unmitigated disaster — for biodiversity, for climate and for human-wellbeing. 

In 1982, the United Nations established the International Seabed Authority (ISA), an autonomous agency tasked with ensuring deep-sea bounties remain the “common heritage of mankind.” Today, the ISA operates on a shoestring budget, funded largely by royalties levied on mining companies; rubber-stamping contracts is how they keep the lights on. In total, the ISA has issued 31 “exploration” contracts, which allow companies to prospect underwater sites, extract minerals in limited quantities and test heavy machinery. Although the agency has yet to greenlight a full-scale commercial mining operation, that could soon change.

In June 2021, Nauru — an eight-square-mile island nation — formally declared its intent to mine the Clarion-Clipperton Zone, a vast undersea ridge stretching from Hawaii to Polynesia. This triggered a two-year deadline for the ISA to publish mining regulations. If the body cannot agree on rules by July 2023, contractors will proceed to mine, plundering the oceans without meaningful guardrails or oversight. 

The scale of destruction would be unprecedented. In a typical mining operation, a deep-sea bulldozer plows the ocean floor, breaking up rocks, steamrolling ancient life and dredging up tons of silt; those fine particles disperse across many miles, clogging gills and suffocating marine life. Metal nodules are then suctioned up to the surface for processing, and the muddy, chemical-laced waste is pumped back down into the ocean. A single vessel, over the course of a 30-year contract, could discharge enough toxic byproduct to fill as many as 400,000 Olympic-sized swimming pools, by some estimates. The most likely result: mass marine death spanning tens, hundreds, thousands of miles. On dry land, biodiversity loss on this scale would be unthinkable. Below the tide, it’s merely the cost of doing business.

Still, it’s hard to decide what’s more unnerving: what we do know or what we don’t. An estimated 90 percent of seabed species remain undiscovered. The bizarre biology of deep-sea dwellers has yielded new medicines, and untold future breakthroughs could be lost to mining. Worse yet, we do not fully comprehend how deep-sea destruction could reverberate throughout the food web. In any case, an overwhelming majority of marine scientists surveyed believe that information is “currently too sparse” to mine responsibly. More than 700 experts have called for an indefinite pause; so too have the governments of Germany, France and seven other nations.

Indeed, a moratorium is the only responsible, evidence-based way to proceed.

Yet, mining executives insist we must forge ahead — in the name of climate action: Reducing emissions, they maintain, requires mineral-intensive batteries. This is misleading on two counts. 

First, ocean sediments store the equivalent of over 7,000 Gigatons of climate warming carbon dioxide, nearly twice the amount of terrestrial soils. Bottom trawling and deep-sea mining disturb this immense carbon sink. Second, research suggests we would be much better served by improving abysmal recycling rates. Less than 5 percent of lithium is recycled, even though it’s possible to recover and reuse 95 percent of the critical minerals found in batteries. In fact, many of the companies that rely on these minerals —including Samsung, Google, Rivian, BMW, Volvo and Volkswagen — have rejected the idea of sourcing raw materials from the seabed.

Although the ISA has signaled it will permit commercial mining, there is another way for UN member states to minimize environmental havoc: high-seas marine protected areas (MPAs). While protected areas are common within national boundaries, there is no legal mechanism for establishing them in international waters. 

At the United Nations, governments recently resumed talks to close this loophole — a process that has been underway for more than a decade. Observers are optimistic that negotiators could ink a deal this time, but it won’t be easy. Governments must first decide how to determine MPA boundaries, fund ocean management and enforce restrictions. Without an agreement, the world’s richest marine ecosystems will be in jeopardy.

Our oceans have already been pushed to the brink by overfishing, industrial pollution and acidification. When it comes to mining, we have the rare luxury of foresight. If we choose to act now, we can prevent incalculable environmental damage — and ensure that oceans remain our common heritage.

Stephanie Wear, Ph.D., is a marine scientist and the senior vice president at Conservation International, leading its Moore Center for Science.