It is an unfortunate reality that with over 8 billion people on the planet almost anything we collectively do has the potential to have huge environmental impacts. When the human population was in the mere millions we could treat the planet as an essentially unlimited resource. But we simply don’t have that luxury anymore. Most arable land is already used for farming, for example. Our plastic waste is clogging the oceans and finds it way to even remote environments. And the CO2 our activities release into the carbon cycle is literally changing the climate.

Sometimes, even when we try to do the right thing, it can have unintended negative consequences. Right now we are engaged in a fairly rapid turnover of our energy and transportation infrastructures away from fossil fuels. Many argue it’s not fast enough, but we cannot assume the alternatives have not environmental impact. Again – anything we do is big. The rare earth metals we need to make batteries, solar panels, and electronic equipment is mined through a toxic process that has negative environmental externalities. If we are going to make billions of electric cars and add massive battery grid storage, lots of solar panels and wind turbines, then we need to dramatically increase this toxic mining, or find alternatives.

For our EV (electric vehicle) revolution the current metals that are the most in demand and resource limited are lithium, cobalt, nickel, copper, and rare earths. Solar relies heavily on copper and aluminum, wind power on copper, zinc, and rare earths (but see the linked chart for more details). We need to develop our land-based mining of these metals if we want to continue cranking our EVs, while also looking for alternatives. There are essentially three types of options to maintain the growth and sustainability of EVs.

One option is to develop new battery technology that does not rely on these metals. This is why there is a lot of effort to develop batteries based on chemistry that does not involve resource-limited material. We need an effective battery made from cheap abundant and non-toxic materials. Much of the current focus is on aluminum, sulfur, and rock salt. Even if we developed a battery that did not have good energy density and could not be used in cars, it could still be suitable for grid storage where size is less of an issue. Then at least grid storage would not compete with car batteries.

The second option is recycling. No matter what other solutions we come up with, optimizing recycling will likely need to be a priority in order to have a sustainable economy. In general we need to move toward a more circular economy. But recycling alone is not enough, as we need to add billions of car batteries to the world.

The third option is to find new sources of existing materials. This is where non-land based mining comes into play. There are vast stores of the metals listed above dissolved in sea water. The world’s oceans have enough lithium to feed our current use of lithium for literally a million years. All we have to do (famous last words) is develop the technology to efficiently, cost-effectively, and environmentally safely extract that lithium. While this option has promise, until the technology is scalable and economically viable, this is still an unknown.

The sea has another potential source of metals – polymetallic nodules. These are potato-sized clump of metal that have formed over millions of years on the seabed in some locations. There is literally chunks of cobalt, nickel, and other metals just sitting on the sea floor. All we have to do is scoop them up. There are already companies planning on doing exactly that.

But of course, nothing is ever simple or easy. Now many scientists are raising alarms that we should not jump quickly into mining the deep sea floor. There are a number of environmental issues. One is that these nodules are not necessarily sterile. Like anything in the ocean, it becomes a substrate for life, a home for ocean critters, and perhaps a source of nutrients. Those sea critters, in turn, are food for other sea life, and it’s all one big intricate web of life. Sucking all the nodules off a strip of ocean floor may therefore have devastating effects on this delicate ecosystem.

Such a process could also stir up the sea floor sediment. This could release a lot of CO2 that is sequestered in the sediment, and actually worsen global warming. It can also cause this sediment to mix with the ocean water, potential disrupting other ecosystems.

Right now these are plausible but theoretical concerns. What many scientists are calling for is a pause before we leap into deep sea mining, in order to study the potential environmental impact. That seems reasonable. But then, of course, we need to massively fund deep sea bed research to answer these questions. Further, can we develop a technique for mining polymetallic nodules that is minimally disruptive? Perhaps we can extract them without disrupting the sediment. Or maybe we can replace the nodules with rocks of similar size and shape but lesser economic value.

We also need an overall strategy. This is hard to do on an international level. The UN has some authority when it comes to international waters, and that is where the focus is right now. But once we get some more scientific evidence about the environmental impacts, we need to collectively decide if it is still worth it to mine these nodules. How much do we really need the materials to continue our battery revolution? What will be the environmental consequences of not mining them? I don’t think it’s a good idea for one company to unilaterally decide what’s best for the world.

I would also like to see some top-level analysis. We have estimated reserves of these metals, but also how long will supplies last? Will they sustain increased demand? Essentially, how long do we have before we will need to find another resource like polymetallic nodules or seawater mining? We can use recycling, new technology, and development of land-based mining to extend our supplies, but for how long? Then we can develop a strategy for sea-based mining. We will know how quickly we need to do the research and get the answers we need.

Perhaps there are still other options out there. I don’t suspect asteroid mining will become a thing anytime soon, but how long would it take to develop it? Then, of course, we need to evaluate the environmental impact of asteroid mining, which would likely require burning a lot of rocket fuel.