A once-promising technology now threatens to create a catastrophe.
As we shift away from fossil fuels and towards a renewable-powered future, our needs change. For example, we need far more cobalt, manganese, zinc, copper, and nickel than ever before, given that they are integral materials for the lithium-ion batteries that go into our EVs and giant grid-level batteries. But there is a problem. Mining and refining these materials has some horrific environmental implications, and we can’t expand our mines quickly enough to cope with the demand, which dramatically elevates the price of the batteries. Fortunately, between 1,400 and 3,700 metres below the ocean surface, these materials are ripe for the picking. Down there, hydrothermal vents create large, globular sulphide deposits chock full of silver, gold, copper, nickel, manganese, cobalt, and zinc. It is incredibly easy to vacuum up these deposits, and due to the high concentration of metal, it is very energy-efficient to refine them. This discovery is how deep-sea mining was born! It promised us ample amounts of cheap, profitable, and low-environmental-impact metals that could power our renewable transformation and halt climate change. But recent studies have cast this promise into doubt. In fact, it looks like deep-sea mining could wreck the planet.
Deep-sea mining has a huge problem: sediment disruption. Sediment, detritus, and dead bodies come together to form a sludge up to two kilometers thick that coats the ocean floor. This environment has changed little since primeval times, and the weird, ancient-looking inhabitants that exist there reflect that. There are no rivers, weather, waves, wind, or large animals that disturb this delicate sediment, and so it has lain mostly unchanged for hundreds of millions of years. As such, the wider ocean ecosystem and, in turn, our own terrestrial ecosystem have evolved around this stable environment. But deep-sea mining will ruin this tranquil corner of our world.
These sediments act as a concentrator. Creatures like phytoplankton absorb a great many toxins that naturally occur in seawater. These phytoplankton then get eaten by larger animals, which absorb the toxins, which eventually die and sink to the sea floor, where they decompose. During decomposition, some of the nutrients get released and return to the water column, but these toxins tend to stay on the sea floor, and over time the concentration of these toxins increases dramatically. This is one of the reasons why ocean sediments are rich in toxic heavy metals like mercury, cadmium, and lead.
When disturbed by deep-sea mining’s giant, vacuum-like confiscations, these toxins enter the water column once more and have a lethal effect. The fine sediment can also take an age to settle back down, and in the process, it fatally clogs up the creatures of the deep, particularly filter feeders.
Just as a reminder
Every time scientists venture to the deep, between 70% and 90% of the creatures they encounter are new to science. We know so little about this undiscovered ecosystem, and yet we are still on the cusp of decimating it.
So why has the development of deep-sea mining continued? Well, it seems many feel like this distant, alien-like ecosystem isn’t worth saving and that we can sacrifice it to save ourselves.
But Mother Earth doesn’t work like that. Remember how I said that even our terrestrial ecology has evolved around this stable ocean floor environment? Well, it turns out that the deep sea is also one of the planet’s biggest carbon stores and has been keeping our planet’s climate stable for centuries. Deep-sea mining will change that.
The Guardian recently reported on an upcoming paper by Fauna & Flora. This report states that, “It has become increasingly clear in the last couple of years that, apart from other dangers, deep-sea mining poses a particular threat to the climate,” and goes on to say, “The deep sea holds vast reservoirs of carbon which could be completely disrupted by mining on the scale being proposed and exacerbate the global crisis we are experiencing through rising greenhouse gas levels.”
This report isn’t exaggerated. There are roughly 2322 gigatons of carbon stored in ocean sediment worldwide. That is approximately 230 times more carbon than humanity emits each year! Now, some of this is in stable forms, like carbonate minerals, but a good chunk of it is just raw carbon dioxide, ready to bubble up to the surface if disturbed. There is also up to 10,000 gigatons of methane hydrate in ocean sediment, again ready to burst upward if disturbed.
If even a small portion of this stored carbon is released, it would be catastrophic! And I use that word with no hint of hyperbole.
Deep-sea mining is the Pandora’s box of climate technology. There are a plethora of companies smacking their lips, eyeing up these resources, and thinking of the mountains of money these deposits could make them. But now that science has revealed the dangers of this process, it is our job to ensure they never get their greedy hands on them. `We must keep this box firmly closed.`