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"Magic Dust" Could Genuinely Save The World.
Enhanced rock weathering is a seriously powerful technology.
UNDO, a carbon capture startup, just secured £12 million in private funding for their “magic dust,” which promises to stop climate change in its tracks. This might sound like a fairytale technology akin to planetary homeopathy, but in actuality, UNDO is pioneering one of the most potent and planet-friendly carbon capture technologies out there: enhanced rock weathering. This technology dramatically speeds up the Earth’s natural geological carbon sequestration pathways, and studies suggest it could be used to store away a massive 2 billion tonnes of carbon dioxide each year! But, how does it work? And can it really save the planet?
Enhanced rock weathering starts in the clouds. Carbon dioxide is soluble, so vast amounts of our emissions are absorbed by clouds. Once absorbed, the carbon dioxide reacts with the water, forming carbonic acid. This is why our pollution is causing vast amounts of acid rain and turning the oceans acidic.
A very abundant type of rock, basalt, strongly reacts with carbonic acid. The acid breaks the basalt down, releasing nutrients like phosphorus, magnesium and calcium, and the acid turns into carbonates, a soluble mineral. These carbonates are biologically neutral, so they no impact on the ecosystems. Once they are formed by acid rain, they flow through the water cycle, and are deposited on the ocean floor, where they can stay trapped for Milena.
This whole process effectively pulls carbon dioxide out of the atmosphere, and safely stores it away in the depths of the oceans, where it can’t cause any climate change.
Naturally, this process is very slow, and doesn’t sequester (store away) much carbon each year. But, using enhanced rock weathering, we can dramatically speed it up using a mine, grinder and a farm. Let me explain.
To accelerate this process, all we need to do is increase the surface area of the basalt and expose it to as much rain as possible. So, if we mine basalt, then pulverize it into a fine powered and spread it out over a large area, we can achieve this. But we need to ensure that the nutrients that leak out of the basalt while it is being eroded don’t build up, as sudden releases of nutrients into an ecosystem can be devastating! So let’s spread the powdered basalt over farmland, where its nutrients can fertilize the soil and be taken up by the cops.
Using this method, scientists estimate that for every tonne of basalt spread over farmland, 0.153–0.165 tonnes of carbon dioxide is taken out of the atmosphere. UNDO is a little more optimistic, and reckons that for each tonne of basalt it spreads, 0.25 tonnes of carbon dioxide are removed from the atmosphere.
Now, global emissions are currently around 35 billion tonnes per year! This means that, even using UNDO’s optimistic numbers, we would need to mine, pulverize and spread 140 billion tonnes of basalt each year! To put that into perspective, the world currently mines 7.7 billion tonnes of coal each year, or 18 times less than this hypothetical basalt operation! And that is, bearing in mind that coal mining is currently at the highest output it has ever been!
You might think that this amount of basalt doesn’t exist. But Basaltic magma (which solidifies to form basalt rock) is generated at mid-ocean ridges at around 20 km3 per year, or 31 trillion tonnes per year. What’s more, there are vast, easy to access basalt deposits on dry land with hundreds, if not thousands of km3 of basalt.
Oddly, the limiting factors here are how quickly acid rain forms, how fast the basalt erodes, and how much farmland we have to spread it over. The only thing we have to figure out is the infrastructure to set all of this in motion. That is why enhanced rock weathering is an incredibly promising carbon capture technology, as it is low tech, cheap, easily implemented, scaleable and has an incredibly high annual storage capacity. In fact, a recent study by Sheffield University suggests that given our current farmland area, levels of acid rain etc, enhanced rock weathering could sequester an astonishing 2 billion tonnes of carbon dioxide per year! This makes it one of the highest annual capacity carbon capture technologies out there.
This is where UNDO comes in, as they want to develop and roll out the infrastructure to unlock this technology, as they see it as the ideal carbon capture technology. In fact, Jim Mann, founder of UNDO, calls crushed basalt “magic dust.” Currently, UNDO is working with farms in the UK that are near aggregate mines for concrete and tarmac production, from which they source their basalt. These mines produce crushed basalt as a by-product, so UNDO isn’t expending any extra energy mining them. They then spread this basalt over the local farms and closely monitor how it erodes.
But, UNDO probably isn’t doing what you’d expect them to be doing. You see, UNDO isn’t developing ways to mine the basalt, get it to the farm or spread it. Those technologies already exist, and are well-optimised. Instead, they are developing ways to verify how much carbon dioxide is properly sequestered.
You see, to be able to use enhanced rock weathering as a carbon offsetting technology, and attract the kind of investment that will enable the technology to grow to 2 billion tonnes of carbon dioxide stored per year, you need to be able to verify how much carbon dioxide you are storing away. That way, you can sell rock-solid carbon credits. Once the money starts flowing in with these carbon credits, UNDO can put in place the infrastructure, such as mines and transport links, needed to expand their operations and start capturing vast amounts of carbon dioxide!
But right now, we don’t have an accurate way to measure how much carbon dioxide each tonne of basalt spread around is sequestering, and how long it takes to do it. This is because so many factors, such as acid rain levels, soil quality, variations in the rock and temperature change the rate that basalt can store away carbon dioxide.
However, UNDO’s unique approach has helped them generate significant funding from the likes of Microsoft, to the tune of £12 million. And, Microsoft will also help audit their projects and verify the amount of carbon dioxide stored, allowing them to start rapid expansion.
When I say rapid, I mean rapid! This year UNDO is planning to spread 185,000 tonnes of basalt and is aiming to have removed a million tonnes of CO2 by 2025!
Now, that is a far cry from the promised 2 billion tonnes per year. But to get this technology onto that scale would require us to set up entirely new global infrastructures, and they take decades to figure out. So don’t be surprised if by 2050, UNDO and other enhanced rock weathering companies get close to this figure. But, is that enough to save the world? After all, 2 billion tonnes of carbon dioxide is only 5% of our current annual emissions! Well, in the coming decades, our emissions will start to fall dramatically thanks to the Paris Agreement. So, by the 2030s it might be closer to 20% of our global emissions, and by 2050 it could be even higher! Therefore, as long as we continue to cut emissions as planned, UNDO’s “magic dust” technology really does stand a chance of being a crucial part of helping humanity reach net-zero.