Spreading rock dust on farms as a climate solution | Hacker News Reader

Spreading rock dust on farms as a climate solution

anthropocenemagazine.org

223 pointspenneyd133 comments

Paper from researchers: https://www.nature.com/articles/s43247-022-00436-3

"Using life-cycle assessment modelling of potential supply chain impacts for twelve nations undertaking Enhanced Rock Weathering deployment to deliver up to net 2 Gt CO2 yr−1 CDR, we find that rock grinding rather than mining exerts the dominant influence on environmental impacts. This finding holds under both a business-as-usual and clean energy mix scenario to 2050 but transitioning to undertaking Enhanced Rock Weathering in the future with low carbon energy systems improves the sustainability of the Enhanced Rock Weathering supply chain. We find that Enhanced Rock Weathering is competitive with other large-scale Carbon Dioxide Removal strategies in terms of energy and water demands."

I found these parts also interesting from that study:

"...it is competitive in terms of sustainability. It has half the energy demand of DACS, avoids land-use competition of other land-based technologies (Bioenergy with Carbon Capture and Storage, afforestation/reforestation/biochar), and has a 10–100-fold lower water demand than these other CDR strategies."

> by 2050, it could be removing up to 30 million tons of CO2 from the atmosphere each year, capturing almost half—45%—of the emissions the UK needs to vanquish from its atmosphere.

The UK emits about 450 million tons of CO2. They are off by a factor of 6.75

https://en.m.wikipedia.org/wiki/Greenhouse_gas_emissions_by_...

You're assuming that the goal is getting to zero CO2 emission? There is no reality where that is possible.

Edit: I hadn't read the article. That indeed seems to be the goal. On that basis, yes the math appears wrong.

Frankly, we probably ought to hit net negative for some while to actually unwind the mess rather than settling for merely stopping accelerating the worsening but I agree with your assessment of the odds.

Agree, and yet (assuming we reach that happy place) what happens next? Who decides how high to wind the global thermostat? Would countries who have benefited from increased temperatures (Russia perhaps) all fall in line and happily agree to go back to (say) pre-industrial revolution levels of CO2?

I'm not sure we need to worry about that until we are magically able to sustain negative or net zero emissions globally. On the present horizon at least it looks like we will be settling for somewhere around two degrees above from pre-industrial temperatures.

Even once (if) we get to negative co2 it will take centuries for the temperatures to drop back to pre-industrial levels. We’re still taking “only” slowing down temperature increase for well beyond the lifetime of anyone alive today.

Isn't that the same issue as currently?

Every country that extracts fossil fuels is deciding to turn up the global thermostat, but rather than calling it out as a decision, we treat it as a default or an irrelevant consequence.

According to Jean-Marc Jancovici (https://www.youtube.com/watch?v=IaQ-U-dP_7M, in french though), this is right on the money: CO2 being extremly stable and given the quantity we already have transfered in the atmosphere, a 1.5°C global rise in temperature is inevitable already. We'd have to in the negative indeed to have a impact, and with the system inertia and the cascading effects, it's not even sure it would reverse the trend completly.

You're right that this would have benefits.

But the (very high) costs also must be considered.

In the end, I'm sure Earth's CO₂ levels will be engineered, and reverting to the preindustrial levels is not at all certain to be considered optimal.

Right now we're so far from being able to return there that we might as well be discussing cities on Enceladus, it's about as doable.

> You're assuming that the goal is getting to zero CO2 emission? There is no reality where that is possible.

If this works then doing it more is clearly possible. Maybe not politically or economically viable in the current circumstances but certainly possible. If weathering fine gravel/dust is the mechanism there’s an awful lot of coastal land with relatively active currents in the UK and elsewhere to dump it.

It's difficult to think of any other reasonable goal that is not at least as "ambitious" as that one. That is, if one considers "trying to survive" an "ambitious" goal.

What do you mean by "zero CO2 emissions"? Do you mean literally emitting nothing, or do you mean offstting emissions with capture, making it net zero?

Carbon zero would probably mean not putting any new carbon into the cycle. Not all carbon emissions are positive contributions to net carbon, if they’re just reusing carbon that was already being cycled through.

Consider as a thought experiment a world where we suddenly have limitless but “clean” power (ie. fusion comes sooner and better than even the most optimistic expectations) and we start doing carbon capture that also produces burnable hydrocarbons as a byproduct. Running an ICE off that fuel doesn’t put any new carbon into the air, it just recycles what was already there. Obviously this isn’t likely, but it illustrates the premise in an exaggerated way.

More practically, in theory wood from farmed, new growth trees fits this mold, but in practice it’s not a terribly efficient or clean fuel once you take all the externalities out. And obviously you’re not gonna power a car on it.

But fundamentally, the main thing we need to do to get to zero is stop breaking the planet’s own sequestration of all the carbon that was in the atmosphere before it was hospitable to modern life. At this point doing that is very much a political problem, we probably have the tech to replace the energy we’d lose from that, we just aren’t willing to build it out fast enough.

I mean, there’s always at least one reality where this happens: the one where climate disasters escalate to the point where human civilization is no longer able to extract new carbon to put into the atmosphere.

The goal is to find a different reality than that one.

sure, except for the fact that positive feedback & runaway warming exist and are likely.

I don’t know what you mean by except? That’s.. exactly what I’m saying.

I didn’t say it would stop climate change, i just said it would stop us from adding more carbon to the atmosphere. I don’t think it’s a good thing.

It’s about half of the UK govt’s target for engineered removals. Page 189: https://assets.publishing.service.gov.uk/government/uploads/...

Yeah, so, off by a factor of 6.75

"By 2050, deployment of engineered removals at large scale, between 75 and 81 MtCO2 per year"

Looks legit?

...so the author of the article either missed that or is intentionally misleading us - because the article definitely gives the impression that it's half the total reduction:

> A new study estimates that the low-tech method could capture almost half the carbon the UK needs to meet its climate goals

> [...]could capture 45% percent of the carbon dioxide required to help the UK meet its 2050 net-zero targets

I'm not sure what you mean by total reduction. The reduction hasnt happened yet, so the total is unknown. But we do know what is needed, and the part you quoted seems to clearly measure the proposal in terms of what is needed, not what is presently output.

A similar idea using olivine: https://www.technologyreview.com/2020/06/22/1004218/how-gree...

This is pretty much exactly the same idea: the paper referenced by the article mentions basalt specifically, which has olivine as a major constituent.

Newer studies have put doubt to olivine's effectiveness: https://www.technologyreview.com/2022/03/30/1048434/why-usin...

That was about putting olivine in seawater, not spreading it on soil.

My concern with all these approaches is the nickel content of olivine, which can be several tenths of a percent.

Yes, you would favor using the low-nickel supply on farmland.

I wonder if nickel in olivine would be harmful on beaches.

Here's a study that found that the olivine hypothesis might not work as expected: https://www.technologyreview.com/2022/03/30/1048434/why-usin...

Previous discussions on this approach:

Spreading rock dust on fields could remove vast amounts of CO2 from air (2020; 109 comments) - https://news.ycombinator.com/item?id=23770718

Potential large-scale CO2 removal via enhanced rock weathering with croplands (2020; 90 comments) - https://news.ycombinator.com/item?id=23831411

There's an obvious path to a future where we can avoid the worst outcomes of climate change affordably using geoengineering.

But the loudest detractors of these ideas are those who feel any path free of suffering or moralizing must be wrong. You can almost never get to a debate on the merits.

I think you're right* It's easy to see who actually wants to address climate change, and who wants to use it as a lever to further a political agenda, by looking at support of different technological solutions, vs support for setting society and human progress back in some way as the only plausible solution.

*(although I'm fuzzy on what can be included in geoengineering - this technology looks interesting and I'm a big fan of carbon capture, I don't support e.g. putting something in the atmosphere to reflect light into space or anything "unnatural" like that. But just removing CO2 from the atmosphere seems safe).

I think we should do everything we can (both reducing emissions and geoengineering) to fight climate change ASAP, but the problem is that a lot of very rich people (e.g. oil companies) are incentivized to not have people reduce emissions & will use the existence of technological solutions as an excuse to only do geoengineering.

We really need both, and as much of both as possible as soon as possible.

> use the existence of technological solutions as an excuse to only do geoengineering.

Actually, they use the potential existence of technological solutions as an excuse to do nothing. The politicians they bought and pay for aren't keen on funding geo-engineering.

And if they did, they'd do it out of general revenue, as opposed to a carbon tax.

Right. Basically we have to account for the existence of bad actors

Bad-actors and geo-engineering, we can't handle even one of them..

> I don't support e.g. putting something in the atmosphere to reflect light into space or anything "unnatural" like that.

Putting gigatons of co2 to the atmosphere _is_ natural?

Dismissing all concerns about geoengineering as moralizing is not reasonable. People are right to be cautious about geoengineering because our track record isn’t great, there are second-nth order effects which are hard to predict in a complex system like Earth, and there is no backup Earth or reset button. To wit, the geoengineering project of pumping tons of CO2 into the atmosphere every day hasn’t gone that well.

There’s this weird streak of purification rituals in modern leftist groups (to say nothing of rightist groups who go to church) that I find disturbing. It’s not just holding the political belief or stance. You have to somehow suffer and be part of the struggle against what I assume is the straight white male patriarchy or something.

Discussed by the late David mackay. http://www.withouthotair.com/c31/page_246.shtml

I really liked his book! I didn't know he died. That's such a shame.

The Future Forest Company spreads basalt on forestland for carbon sequestration [1].

Wren offers it as one of its carbon offsets [2]. However, it is currently the most expensive of their offset programs, per ton of carbon offset or removed, and significantly so.

[1] https://www.fastcompany.com/90642582/this-company-is-crushin...

[2] https://www.wren.co/projects/mineral-weathering-in-scotland

I think these mineral weathering programs may make the most sense when applied to the oceans, where they both sequester carbon and directly reduce the ocean acidification that is harming marine life. This is especially the case if wave action on beaches can reduce the amount of energy required to grind and distribute the rock. There also seems to be potential for additional capture by the iron content of the rock fertilizing the growth of phytoplankton in areas where that wouldn't be harmful to other marine life like coral. In areas with tropical coral adding Calcium both reduces acidity and helps shell building creatures.

I am also leery about spreading mountains of silica dust on fields where it can be blown in the air and end up in our lungs eventually.

re phytoplankton/marine life: I guess basalt particles will sink. But if sinking is slow the top layer will get murky absorbing the light.

Crushing and distributing the required amount of rock seems challenging. Unless crushed rock is really produced enough by mining and is somehow really cheap to move (eg trains are coming back empty anyway)? It probably also adds another trip around the field for the combines?

Still, if it's this easy we really need to be doing this.

The article does point out that the folks who studied this accounted for the carbon cost of doing that in estimating the capture benefits.

Yes, crushing and distributing is one of the main drawbacks. Too far from a mine and the net emissions are positive.

It sounds like the potential of this technology is enormous so i would guess the distance would have to be very long before the emissions vaccine bet positive. Also there might be ways to combat that.

Our fastest carbon sequestration method that scales are forests right now and they are slow to grow and need dedicated space. So let's build those EV combines or whatever it takes to keep rock dust net negative.

There is probably a lot of leftover rock from extracting everyday things like aluminum, as well as rare earth elements, which electronics manufacturing needs for many components. If the generation of the stones that get crushed and used for dusting is an output of other essential mining projects, that could further offset the costs associated with generating rock dust. It could also potentially reduce the shortage of these rare earth minerals, and associated electronic components, by attracting more mining operations to operate in additional countries.

What about silicosis?

Rock dust doesn't sound very healthy. People and animals next to the farm will breathe it when the weather is dry.

Seems like your question answers itself. They will not use silicate minerals in their mix of rocks.

From the paper:

"...which involves modifying soils with crushed silicate rocks, such as basalt."

1. How much additional energy does it take to pulverize the rock? 2. What about the effect the rock will have on soil pH? 3. What about leached salts and heavy metals?

Pulverizing rock requires little energy, if I recall correctly. This shouldn't be too surprising as one is breaking only a small fraction of the chemical bonds in the material.

Pulverizing rock is one of the most energy intensive activities on the planet.

The limestone crusher a few miles from my home can’t use more than 400-500 kW/hr judging by the power lines.

That is limestone, the article talks of basalt which seems would require more.

kW-hrs/hr, I presume you meant. Which is to say kW.

Fortunately, rocks can be crushed with power from solar panels. There remains the issue of whether those panels are better used, just now, to displace natural gas burners emitting new CO2 than to crush rocks to absorb CO2. Or, equivalently, if NG-generated power used to crush rocks makes more CO2 than would then be absorbed by the rocks.

In a near enough future, it won't matter, because the NG will all have been displaced already.

People used to do it with hammers.

They still do. I saw little kids on the African continent doing it recently.

I was wondering the same thing. Mine dust? Seriously? Sounds like heavy metal poisoning to me.

Crushing ore is part of the typical milling process, so depending on the source of your material, it's already milled to a pretty fine dust.

I'm way more concerned with the side effects of the process as others have mentioned. Maybe not heavy metals, but soil PH, and other poisons.

Also consider that volcanic rock contain every elements necessary for plant and animal life. Volcanic rock dust + wood chips is a popular organic way to increase soil fertility. The rock supply all the elements and the wood chip the organic matter to feed the mycelium and other soil life.

It’s also a way to move away from chemical fertilizer made from mined minerals and natural gas

So why would rocks do this but not the soil that’s already on the ground there? Isn’t it basically the same stuff?

The surface area of a mountain and the surface area of that mountain ground into fine gravel are very different. The same thing happens to the surface area in both cases, yes.

The rock that's in the soil may not be the correct type, or it may have already reacted, or it may be in chunks that are too large to dissolve on human-relevant timescales. The idea is that you want ultramafic rocks, which are low in non-reactive Silica but rich in Magnesium and Iron oxides. These oxides absorb CO2 from the atmosphere to form carbonates and bicarbonates, sequestering it for geologic time. However, since reactions can only occur on the surface and when the minerals are dissolved, a big pile of mine spoil or river-sized rocks buried in the ground aren't doing much to absorb CO2. But if we grind it up into rock powder and spread it over fields, or crush it up into sand and dump it on beaches to let the ocean do much of the work of grinding and distributing it, the vastly increased surface area means a significant amount of CO2 can be absorbed in a human lifetime.

There can also be pros or cons associated with the minerals in the rocks. For example, you don't want to spread rock containing heavy metals on fields where you grow food. On the other hand, rocks rich in Potassium are a beneficial fertilizer, and Iron-bearing rock spread in the ocean can encourage the growth of phytoplankton that further absorb CO2.

Soil with CO2-absorbing minerals that’s already exposed to the air would already have absorbed the CO2. It’s like saying why plant trees to remove carbon from the atmosphere when we already have trees.

Olivine is a particularly easily weather silicate, because the silicon atoms are in isolated SiO4(-4) tetrahedra. In most other silicates, the silica tetraheda are linked covalently by shared oxygen atoms and weather much more slowly.

The minerals in the soil have already been weathered and absorbed as much CO2 as they can. The important thing to understand is that it is only accelerating a natural process that has kept earth's temperature relatively stable for billions of years. This is true long-term carbon capture and it is worth researching the best way to do it.

Adding iron to the ocean to fertilize carbon sequester ING plankton is a interesting related approach: https://en.m.wikipedia.org/wiki/Iron_fertilization

Is this meant to be spread on cropland? I figure so because they say farmland and the (stock?) photo appears to be crops but I didn't see it specifically mentioned. What affects will it have on the crops?

"It depends" some rock is net beneficial, can be both structural, physical-chemical effects on soil regarding clumping and water retention, and bio active (supporting beneficial micro-organisms, providing micro nutrients)

Some phosphate rich rocks might be also known as.. fertiliser.

Arsenous rocks would be a disaster. It's a huge issue in India with water table and ground contamination. Likewise lead, or salt (in the wider sense if it causes brackish ground water) although that's about deep wells. I have no idea if this is a serious risk for rockdust plans.

For enough upside benefit downsides might have to be borne or mitigated.

Basalt is mentioned in the article. I know just a little bit about farming and growing things but I don't know anything about this rock stuff. But if it's good (or, perhaps, at least not bad) for the crops then it does seem like a possible good idea.

Basalt rock dust is a pretty common amendment to add trace elements to soils especially in organic gardening

The type of rock dust they are talking about is already commonly used as a soil amendment to add trace elements and minerals. That said it is possible I suppose that the optimal amount for carbon drawdown is greater than the optimal amount for crop health or yields

Probably a sort of crunchy effect, but hey it's high in minerals

A normal soil ecosystem has fungi breaking down rocks to gather nutrients and sometimes exchange with plants. It could be a sort of fertilizer but certainly there would be a point of over applying which would have to be understood.

Clearly if you are putting it on farmland, the farmer will demand the beneficial stuff and reject the harmful stuff.

There are lots of opportunities for harm, but plenty of material that would be beneficial, particularly for crops that like higher pH.

Olivine, e g., often has excess nickel, which you then would not use on farmland. You might dump that on beaches, instead. The main thing is to move a lot of it. You would prefer to use renewable electric to crush it, but the main thing is to get started.

Where I live, beaches are virtually sacred and certainly not the places to dump anything.

Olivine makes them a pretty, glassy green. But anyway you would put it on the many, many thousands of miles of shoreline where people are not, to be stirred by wave action.

And then there were no more ghost crabs, because their sand-colored camouflage was no longer effective.

Way better than being unable to produce any exoskeleton at all. Which is where we are headed.

If you lived near South Point, Hawai'i Island, you'd already have a (natural) olivine beach.

Adding that to my must sees if I ever get back to Hawaii.

> The simple act of sprinkling rock dust—an abundant byproduct of mining—on farmland could capture 45% percent of the carbon dioxide required to help the UK meet its 2050 net-zero targets.

Has this news been brought to me via the 'mining board'? Is it an attempt to get us to pay for their waste?!

And won't rock dust degrade the soil quality?

Depending on the size, it would be like putting a sand through the soil. Great for drainage.

> "assuming a baseline application rate of 40 t ha−1 yr−1 of basalt rock dust"

I am sorry, what? 40 tonnes of basalt dust per hectar?? What's hilarious is that when you look up basalt dust on internet, merchants sell it in bags of 2kg, "to be applied 20 grammes/sq meter", while 40t/ha is 4kg per sq meter!

So, I did exactly that and got a recommendation of up to 10lb per 100 sq feet, which is over 4kg/9sq meter, off the first hit.

Compare Gwern's proposal: https://www.gwern.net/CO2-Coin

What happens after multiple layering / years after, won't you at some point remove rock layer to keep fertile soil

Any obvious downsides to this approach?

Might need to be studied in different regions to determine whether there are any detrimental effects. It looks like it might alter the soil pH which could affect crops.

Sounds promising though.

Do rock minerals capture more oxigen than carbon?

They are mostly already oxidized.

And it wouldn't matter too much (within reason): we have vastly more O2 in the atmosphere than CO2 we want to get rid of.

The CO2 is at <0.05% concentration. O2 is at >21%.

Also, inevitably running out of rocks.

Can somebody who knows about rocks weigh in here? I was under the assumption that pretty much the whole Earth crust was made of rocks, and that we’d run out of virtually any resource before we run out of rocks.

Basalt is extremely common, its not something that anyone will run out of.

We may run out of basalt sources that are close enough to farmland it can be spread on, but it would take a while. And trains would change the economics.

I'd imagine the types of rocks would matter. There are also a lot of ores that should remain in the ground, and not pulverized and spread, contaminating water and soil.

All the oceanic crust is made of basalt, so approximately 2/3 of the planet is covered by several miles of it. Unfortunately mining oceanic crust is impractical, for obvious reasons. However some oceanic crust got trapped between mountain ranges during continental collision, forming ophiolites. These can be suitable mining sites, together with LIPs (large igneous provinces) and the rocks of some shoshonitic (K-rich) basalt volcanoes.

Rock is not a scarce resource. The planet is literally made of it.

We're all just pond scum on a ball of molten iron.

Yeah, but it isn't an infinite resource. Eventually, I meant, inevitably, I wrote.

Nothing is infinite. For the purposes of grinding basalt rock to sprinkle on farms, it is essentially sufficiently abundant that it doesn't matter.

Mining the rocks, distributing the rocks to a central processing center, then shipping to the farms is all non-negligible and can easily be net positive emissions rather than sequestration.

It looks like they've considered that:

>Their model also incorporated the emissions costs of mining and then spreading this powdered rock over fields.

Of course, there's always a chance of errors in both how they estimated these emissions and how they estimated the amount of CO2 that will be removed.

> Transportation. Detailed transport analyses (based on UK road and rail networks) were undertaken to calculate distance costs and CO2 emissions for the distribution of rock dust from source areas to croplands. We used the GLiM database for the UK distribution of basalt deposits and the 2019 land cover map (Supplementary Information) to calculate transportation distances, cost (£ t−1 rock dust km−1) and emissions (tCO2 km−1) from potential local rock sources to cropland areas, together with UK road and rail transport networks. Spatial analysis was undertaken with least-cost path algorithms from the ArcGIS software.

Yea, it sounds like the model took this into the account, maybe the assumption that rock sourcing could rely on mines within the UK. If so, given the size of the UK, if the majority of transportation is by train and EV over UK distances, this might not be an issue.

It costs a lot of money.

Nickel pollution.

Is "rock dust" proven, peer-reviewed and reproduced or is it some pet-theory of an academic or two?

Because one thing I've noticed especially over the past two years of covid research, once some PhD seems to vapor-lock onto a single substance as a "miracle cure" they can write endlessly, breathlessly about it without mentioning a single downside or limitation.

I have rocks to sell if anyone's buying.

Whatever it takes so that nobody in America has to make any substantive changes in their way of life.

Article is about the UK, but regardless, if it can be done, why not? You got some kind of neocatholic guilt going on? "Climate change mitigation doesn't matter if it doesn't come with a heaping side of suffering".

It can’t be done — that’s the problem. Anybody who thinks the “answer” to climate change is anything but sweeping changes to the Western way of living is sadly mistaken. Either it happens through choice before things get too awful or by necessity when things get more awful than anyone alive today is willing to imagine.

You can stick your head in the sand and think “boy this rock dust will definitely do the trick…” or you can come to terms with the truth. Climate change is going to deliver suffering whether we mitigate it or not.

I have no guilt. I don’t have kids, I live in a small apartment. I don’t eat meat. I don’t drive. I don’t go on airplanes. Even that isn’t enough, but I sleep fine.

If the rock dust captures so much CO2, what will the plants breathe?

I think the idea is to get the CO2 levels to what they were 200 years ago. Plants breathed fine back then.

Why 200 years, an not say few million years? Used to be more CO2 and plants liked it better. Definitely grew higher back in those days.

I suspect the answer 200 because it is assumed these days that CO2 produced since 1800 is all man made. Would like to genuinely know if that's the case or I'm missing something.

There was a rapid growth of CO2 that started around 200 years ago[1]. To get a time with the same levels as today, we have to go back 14 million years[2]. Back then the species alive were different than the species alive today, with one notable difference being humans. I don't think it's safe to assume we can take the CO2 levels back tens or hundreds of millions of years and assume the species alive today will handle that well.

>I suspect the answer 200 because it is assumed these days that CO2 produced since 1800 is all man made. Would like to genuinely know if that's the case or I'm missing something.

I came up with the number 200 because that's when the graph looked like it started going up. I definitely think it was caused by humans, but I didn't pick the number 200 based on some human historical event, but rather just by looking at the graph. Regardless of whether it was caused by humans, I think such a giant increase is disturbing and should be carefully analyzed for potential problems and dealt with if there are any. AFAIK, there was no CO2 increase as steep as this in history even going back hundreds of millions of years.

[1] https://www.co2levels.org/

[2] https://en.wikipedia.org/wiki/Carbon_dioxide_in_Earth%27s_at...

Isn’t that adding more dead dirt to dead dirt, rather than cultivating soil? How does rock dust encourage soil bacteria and fungi that symbiotically trade minerals for sugars with the plants?

It might be low-tech, but it’s not really a regenerative approach.

I am a worm farmer and soil amendments manufacturer. One of the most important ingredients that I feed my worms is blue metal and zeolite rock dust. Trace minerals including elements like boron and sulphur are important for cellular growth. The Australian continent where I am has extremely weathered soil, depleted of minerals. I hope to help put minerals and biology back into the soil.

It's hard not to be skeptical.

If only there was a way to solve climate change with carbon capture that was low tech, easy to do, simple to understand, didn't pose any long term side effects and pretty cheap to do.

Oh, and it can solve all the CO2 emissions you could ever want, so you know, you don't even have to make significant changes to your industry or way of life, because your emissions are pretty much flat out neutralized by this one simple thing.

Sounds perfect right?

Sounds like a silver bullet.

...but, silver bullets don't exist.

So, I can guarantee it's not that simple. Maybe it's another useful tool to help tackle climate change, probably with more research as to how to actually works. ...but, I think anyone who's excited by this needs to calllllmmm the F down, because this idea has been around for quite a while, and no one is using it; so I suspect there are some things that still need to be figured out like:

- do the benefits scale linearly, or is it a logarithmic curve (like most things)?

- can you actually measure the amount of carbon captured to prove its working?

- does it have any side effects on the ecosystem?

- does it have any impact on, you know, the farms you're putting it on?

- does their model (which is all they did, create a Matlab model) actually work in the real world?

- how often do you have to do it for it to stay effective?

It's complicated right.

I mean, sounds promising... but this:

> The simple act of sprinkling rock dust—an abundant byproduct of mining—on farmland could capture 45% percent of the carbon dioxide required to help the UK meet its 2050 net-zero targets.

Is just idle wishing the problem away. It might. It might not. There's a model that suggests it might.

I'm not convinced we should be sprinkling rock dust over the entire country quite yet.

> carbon capture that was low tech, easy to do, simple to understand, didn't pose any long term side effects and pretty cheap to do.

Plant a tree.

Pshaw. Plant lots of trees.

Even poorly educated, dirt poor people in underdeveloped countries can do it. (And are. See for example Pakistan, where they are planting 10 billion of them.)

> Sounds like a silver bullet. ...but, silver bullets don't exist.

There are many, many examples of miracle technologies that have huge effects for the resources expended on them: antibiotics, vaccines, printing, writing, mathematics, the transistor.

"Put extra dirt on your fields" isn't really in the same class as those is it?

How do you define classes?

For something that sounds similar:

When people didn't understand soil and biology very well, fields needed long fallow periods to recover from growing wheat and other crops.

As part of the British Agricultural Revolution, they figured out that they could plant turnips and clover instead:

> One important change in farming methods was the move in crop rotation to turnips and clover in place of fallow. Turnips can be grown in winter and are deep-rooted, allowing them to gather minerals unavailable to shallow-rooted crops. Clover fixes nitrogen from the atmosphere into a form of fertiliser. This permitted the intensive arable cultivation of light soils on enclosed farms and provided fodder to support increased livestock numbers whose manure added further to soil fertility.

https://en.wikipedia.org/wiki/British_Agricultural_Revolutio...

Putting the right kind of extra dirt is in the same class. Fertilizer can increase yields by 20% or more. That’s a magic bullet. Technology is nothing but the quest for magic bullets.

It’s not.

There are no magic bullets.

Every action has consequences; as you see from the effects of using fertilisers and pesticides.

“Perfect fixes” with technology don't happen. Perfect fixes have no side effects. That’s incredibly difficult to achieve in complex systems.

Whether you want to believe it or not, doesn’t change the facts.

Breakthrough transformative technologies do exist, but those simply change things they don’t magically fix them.

What you’re espousing is not “truth”; it’s simply a philosophy, considered by many to be a short sighted trivialisation of a complex problem. See -> https://en.m.wikipedia.org/wiki/Technological_fix

"Wash hands" was a simple silver bullet in medicine.

- does it have any side effects on the ecosystem?

- does it have any impact on, you know, the farms you're putting it on?

These two questions probably already have an answer: we already grow plants, vegetables, fruit trees on basaltic soils (soils formed by the erosion of basaltic rocks). Some European countries have almost only them, like Iceland, Albania, Montenegro. Usually the crops are excellent, and benefits directly from this natural fertilizer e.g. some Italian wines. These rocks also help to capture water in arid regions, btw. We are also plenty of real world experiments of adding these substances to other ecosystems: every basaltic volcanic eruption distribute a dust cloud around the vent, usually in an area of hundreds km^2, influencing the environment.

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