Study: Spreading Crushed Volcanic Rock Would Curb Anthropogenic CO2

Bali Volcano Mount Agung November 2017 Eruption

Bali Volcano Mount Agung November 2017 Eruption. By Michael W. Ishak ( [CC BY-SA 4.0], via Wikimedia Commons

Guest essay by Eric Worrall

A new study suggests spreading crushed volcanic rock across the world’s farmland would absorb enough CO2 to curb global warming, so long as a cost effective means to crush all that rock can be discovered.

How Crushed Volcanic Rock in Farm Soil Could Help Slow Global Warming — and Boost Crops

A new study explores how planet-warming carbon dioxide could be absorbed using ‘enhanced rock weathering,’ a natural process sped up to fight climate change.


Pulverizing volcanic rock and spreading the dust like fertilizer on farm soils could suck billions of tons of carbon from the atmosphere and boost crop yields on a warming planet with a growing population.

In a paper published this week in the scientific journal Nature Plants, an international team of researchers lays out the prospects for “enhanced rock weathering”—a process that uses pulverized silicate rocks, like basalt, to speed the ability of minerals to store carbon in soil.

This could happen fairly quickly. “Conceivably, roll-out could take place within a decade or two,” said David Beerling, director of the Leverhulme Centre for Climate Change Mitigation at the University of Sheffield and the lead author of the study.

Read more:

The abstract of the study;

Farming with crops and rocks to address global climate, food and soil security

David J. Beerling, Jonathan R. Leake, Stephen P. Long, Julie D. Scholes, Jurriaan Ton, Paul N. Nelson, Michael Bird, Euripides Kantzas, Lyla L. Taylor, Binoy Sarkar, Mike Kelland, Evan DeLucia, Ilsa Kantola, Christoph Müller, Greg Rau & James Hansen

The magnitude of future climate change could be moderated by immediately reducing the amount of CO2 entering the atmosphere as a result of energy generation and by adopting strategies that actively remove CO2 from it. Biogeochemical improvement of soils by adding crushed, fast-reacting silicate rocks to croplands is one such CO2-removal strategy. This approach has the potential to improve crop production, increase protection from pests and diseases, and restore soil fertility and structure. Managed croplands worldwide are already equipped for frequent rock dust additions to soils, making rapid adoption at scale feasible, and the potential benefits could generate financial incentives for widespread adoption in the agricultural sector. However, there are still obstacles to be surmounted. Audited field-scale assessments of the efficacy of CO2 capture are urgently required together with detailed environmental monitoring. A cost-effective way to meet the rock requirements for CO2 removal must be found, possibly involving the recycling of silicate waste materials. Finally, issues of public perception, trust and acceptance must also be addressed.

Read more (paywalled):

In my opinion this is one of the most terrifying geo-engineering schemes I’ve ever seen.

Leaving aside the hopefully insurmountable issue of finding affordable means to crush and distribute all that volcanic rock, imagine the consequences if the scheme went too far, if CO2 levels undershot the desired target range.

In the last ice age, CO2 may have dropped as low as 180ppm. Life on Earth was almost extinguished by lack of CO2.

Assuming the scheme worked, it wouldn’t take much of an undershoot to bring life on Earth back to the brink of CO2 starvation. Even if the undershoot didn’t kill everything, it would almost certainly trigger widespread famine as global agriculture collapsed for lack of CO2 to fertilise the crops.

Higher CO2 levels are nowhere near as hazardous as lower CO2 levels. If CO2 climbs by 200ppm, or even 1000ppm, so what? Life would still flourish across most of the Earth, just as life flourished in past epochs when CO2 levels were high. But if CO2 levels dropped for whatever reason, by 200ppm or more, the world might end.


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Perhaps the author fails to understand how CO2 levels became so low in the atmosphere in the first place?

This is yet another example of more of your taxes being wasted on a worthless study.

I would say the idea has a lot of merit. It’s hard to define what type of research is worthless or not, until the idea is found to pan out (or not). If we didn’t allow people to research and come up,with new ideas we would be 100 years behind the ball.


Not only is it worthless and unnecessary, it also contains the mandatory plea for more research aka funding.

Extreme Hiatus

fernandoleanme – Sounds good in theory but this will never get close to cost-effective or as net CO2 reduction even with a pile of naturally crushed rock conveniently beside a field. Could be useful in the right location on a small scale if it actually improved crop growth; garden stores sell it. But that misses the supposed global idea, and always will, so that makes it useless research.
How about building thousands of giant skyscrapers covered with hanging gardens of crops and other plants?
That would also absorb CO2 and produce more food.


Some ideas are so obviously stupid, that you don’t need a study to figure it out.

John Harmsworth

Of all the climate change stupidity we have been subjected to, this is the single most stupid idea of all.

Extreme Hiatus

An economic reality check on this stupid idea. This sand actually produces a real tangible product that people are willing to pay for:


It is not a worthless study. If energy is cheap enough, it becomes practical to do. So how much energy is required and what is the price per unit of electricity necessary to justify the effort. Without at least suspecting that this is a possible solution, nobody will do the math. That pointer effect makes the study useful even if energy doesn’t actually get that cheap in this lifetime.


Volcanic ash is a good fertilizer.
Though there are lots of better, cheaper fertilizes available.


Iceland might be the perfect place to test the validity of this theory. It is covered in volcanic ash, has almost unlimited supply of low cost geothermal and hydro electricity, and is very sparsely populated. The only challenge would be to persuade the citizens that they need to cool their beautiful island, much of which is already covered by ice fields and glaciers.

michael hart

Yes, I’ve often read that things like powdered granite from glacial deposits actually make a good slow-acting fertilizer. Perhaps some farmers might comment on the relative costs. I doubt that ‘overcompensation’ would be a serious problem for atmospheric CO2 because it would be quite limited in both rate and in area. Which is why the idea would probably fail in its stated objective of significantly reducing CO2: Human agriculture is only the tail on the dog, and we already use a lot of fertilizer.


@ Mohatdebos
Besides, I bet Icelanders are first rank to fight climate change. This would be so horrible, if it turned back to climate their ancestor colonist experienced… with all those horrible green things instead of immaculate ice. Bwa. disgusting.


This study has so many things wrong with it it’s hard to know where to start. The most obvious one is that farmers already use mineral fertilizers to increase production. They understand the costs and benefits of adding crushed rock and do so if it adds value. They would use more if it made sense to do that.
Crushed limestone is most common, but there are a few areas where crushed basalt is used. It is not used widely as it is too expensive to grind basalt to the size range required – it is a very hard rock, which is why it is valuable as a building aggregate. It is expensive to transport rock, so a local source would needed. Then see how you go trying to open new quarries to provide the rock – in most developed countries that starts a prolonged fight with nearby residents and environmentalists.


Indiana Agricultural Report. The guest expert was talking about sulfur depletion in soil. He said that farmers had not had to worry about it because in the past “acid rain” had kept the sulfur concentration in the soils within the optimum range for most crops. However now it is being found in many fields that sulfur concentration levels are dropping below the optimum range for the most common crops grown in Indiana and that farmers need to ask specifically for testing for it because it is not part of the normal soil analysis. So now what farmers once got free they are going to have to pay for to be sure their yields and crop quality do not decline. Who would have thought that there was a benefit from “acid rain”?
Sulfur is a 2ndary nutrient, required to metabolize N in the plant so that protein is made.


Let’s imagine that some ‘cheaper’ way of excavating volcanic rock, pulverising, distributing and spreading it can be devised.
I’m sure it can.
Just look what innovation has done with fracking.
But the energy necessary for all those tasks can’t be reduced below the requirements of basic Physics.
Where is that energy coming from?
A better idea would be to equip rent seeking fake ‘scientists’ with picks, hammers and wheelbarrows to undertake a large scale trial.
At least it would keep them fit and doing something for society, whether it worked or not.


A cheaper way to spread volcanic ash?
That one is scarily easy. Just use a nuke to blow the top of the Yellowstone caldera.
Even more scary; The resulting food shortages would help advance the ‘proletarian revolution’. So the alt-left might even try it…. ‘to save the planet’.


But…..Keep in mind that much of the fertilizer that is currently used to fertilize crops (and lawns, etc.) is produced by mining and crushing minerals such as potash and phosphate.
Would crushed volcanic rocks provide a viable substitute for the minerals that are currently in use? Elifino, but if it would, consider this to be a boon to future prosperity — That is, right up to the time that there’s no more fossil fuels to provide the energy needed for mining, crushing, transporting and spreading minerals of any kind on the fields. So sad. Then farmers will likely be looking for ways to increase the amount of CO2 that is in the atmosphere in order that their crops can be more productive.
And here we go loop-ta-loop.

John Harmsworth

The more rock they spread as fertilizer the more crop yields would be reduced by declining CO2 levels. That’s if they can figure out how to do this without using fossil fuels. Regardless, we have no reason to think that lowering CO2 levels would cool the planet anyway or even that a colder planet is a good thing. A fundamentally stupid idea.


Why not fusion?

The idea of enhanced weathering isn’t new. There is a 1990 Nature paper by Seifritz, for example. Burning carbon or hydrocarbons creates acidic CO2, and the permanent sequestration is neutralization with a base (to mineral carbonate). But base on that scale is hard to find, and volcanic rock is the most likely source. Unaided, it is very slow to react.
The idea would be expensive, maybe impossibly so. For each ton of C burnt, many tons of rocks would have to be crushed. I don’t think there is any risk that they would overdo it.


“Unaided, it is very slow to react.”
Volcanic rocks actually weather very quickly and yield fertile soil, particularly in warm and wet climates. That is the main reason active volcanoes in the tropics are usually densely settled almost to the crater rim.


I believe that is ash that is weathering, not the rocks themselves.

Curious George

Ash is a finely crushed volcanic rock. Isn’t it also saturated with CO2?

What would be just marvellous is any evidence that a measure like this is a sensible proposition in the first place.

Clyde Spencer

You said, “Unaided, it is very slow to react.”
That is why “crushed” volcanic rock is specified. The chemical reactions are enhanced by increased surface area.
You also said, ” I don’t think there is any risk that they would overdo it.”
And if your infinite wisdom were to prove to be fallible, what would be a quick-acting, back-up remediation plan?

“That is why “crushed” volcanic rock is specified.”
And why “unaided” was specified.
“And if your infinite wisdom were to prove to be fallible”
You’ll be glad to know I wouldn’t be in charge. But the process of grinding and transporting the rock would be more expensive than the original mining of carbon. If done, I think it would be paid for with great reluctance.


In “A Many Coloured Glass”,(Page-Barbour Lectures), Freeman Dyson looks at a less dangerous geo-engireering process of adding biomass to the arable land in the US and mentions one figure only, one-hundredth of an inch, to be added annually going forward for one hundred years.
He says,”The point of this calculation is the very favourable rate of exchange between carbon in the atmosphere and carbon in the soil.To stop the carbon in th atmosphere from increasing, we only need to grow the biomass in the soil by one-hundredth of an inch per year…..
I conclude from this calculation that the problem of carbon dioxide in the atmosphere is a problem of land management, not a problem of meteorology.”
Professor Dyson concludes,” At present we do not know whether the topsoil of the US is increasing or decreasing. Over the rest of the world because of large-scale deforestation and erosion, the topsoil reservoir is probably decreasing.We do not know whether intelligent land management could increase the growth of the topsoil reservoir by four billion tons of carbon per year, the amount needed to stop the increase of carbon dioxide in the atmosphere.All that we can say for sure is that this is a theoretical possibility and ought to be seriously explored.”


Postnormal science will destroy the world. QED

Moderately Cross of East Anglia

Isn’t spreading vast amounts of crushed volcanic rock exactly what stratovolcanoes and pyroclastic flows do already without the need for us to inadequately and expensively mimic.
It’s not as if we don’t know massive eruptions cool the biosphere so perhaps as warned above we ought to leave this sort of geo-engineering alone.
But I did like the suggestion that all the eco-looney tunes could be given a hammer and piles of pumice to occupy their time more productively than their present engagement.

John Harmsworth

The next climate summit should be held at the top of Vesuvius and all the attendees can fetch back a pocket full of rocks if they survive.


OT but Jonova has a very interesting graph showing the effect of “renewables” on electricity prices.

Willis’ chart is an equally interesting complement here:

Aided by manipulated and falsified Climate Records, the Warmistas are continuing to keep the general population in the dark about the really important roles of CO2 in the atmosphere and on Earth,and the minor and insignificant roles of CO2 in the atmosphere. The advancement of the Scam developed by the Warmistas, to move money to their pockets, depends on the continuing ignorance of the science by the bulk of the population. Studies like this “Spreading Crushed Volcanic Rock Would Curb Anthropogenic CO2′ is yet another of these obfuscation attempts.

Michal Malženický

Today, only the weak-minded do not understand that brutal geoengineering and LENR is needed soon. All of these technologies must be tested without exception, to a small extent, to experience their effects, of course, one after the other. In this case, Trump may be right not to apply gentler procedures.

Moderately Cross of East Anglia

Perhaps you should specify what brutal geo-engineering you have in mind? My view is that it is exactly this form of insanity we need to avoid. What are you going to do, fire millions of reflective metal foils into the upper atmosphere and then apologise nicely when you screw up the night sky and send the planet into a permanent ice age. Great idea, not!
Or perhaps you had in mind what the green lobby has in mind and is well on course to achieve, impoverishing millions and killing most of the poor and human race for a non-existent problem
Playing fast and loose with “brutal geo-engineering” when we you don’t have an understanding of the consequences just qualifies as gross stupidity and so far the alarmist side hasn’t even got any of its major predictions remotely right. Like the prediction that by 2000 major Asian port cities would be underwater and the world have 50 million climate refugees. Perhaps you could list the names of those cities that have suffered that fate before screwing around with the planet?


Why is it that you believe that “brutal geoengineering” will soon be needed?

A mining company representative told me that 25% of the world’s energy use was used in crushing rock!


Sounds a bit extreme.


Sounds like traditional mining used to process everything we use in our modern advanced civilization.


This is a repeat. I vaguely remember some inconsiderate person the calculated the energy required to crush the rock and the CO2 generated in doing so. Funny!.


rockdust is brilliant for plant growth but its around 2 to 3 yrs to max benefit
and it needs to be the right blend for the area
sinabung just lobbed a chunk of itself skyward i read so aerosolised rockdust cooling coming up;-/


Academia… Is that where all of the marginal minds end up?

John Harmsworth

These guys are well below any margin you can imagine.Unless you have some fusion powered flying dump trucks they can borrow.


I’ve said it before and I’ll say it again…
Anybody that conducts geoengineering work on a planet they are living on is CRAZY !

dumping c02 with impunity is geoengineering

DC Cowboy

As is irrigating large areas of the planet, deforestation, building large cities, etc

Bruce Cobb

Breathing is “geoengineering”. Living is “geoengineering”.

John Harmsworth

So what saved the planet back when CO2levels were 6000ppm?

Peta of Newark

Far too many authors – how does Willis’ Rule about that work out the depth of BS?
Extremely contrived and complicated, they really have bamboozled themselves – primarily due to their total fixation on CO2 – but other going in the right direction.
Volcanic rock dust is adding back to the farmland the nutrients removed by weathering. All the tiny little micro nutrients that no-one thinks about. Copper, iodine, cobalt, selenium, manganese etc etc
Rock Dust is a genuine fertiliser. I’ve said it a million times round here, as fas as plants go, volcanoes are veritable Fountains of Ambrosia.
Where they go further wrong, to my experience of getting rock dust from the garden centre, Volcanic Rock Dust can/does/may have a fairly high ‘neutralising value’
IOW, it contains limestone. Ohhhhh, it that why volcanoes emit CO2?
Hoooda Thunk that?
But in fact that is partly why it works as a fertiliser. The process of weathering by acidic rainfall (all rain is acid)
added to the decomposition of organic matter creates acid. Humic Acid to get ‘all technical’
And and and, recall Global Greening, supposedly caused by extra CO2?
The green is coming from farmers using nitrogen fertiliser and also nitric acid raining down from the sky after almost anything is burned in an Earth-like atmosphere.
Yes, the acid releases micro nutrients and the plants grow better, bigger and greener.
BUT, that acid puts the brakes on the activity of the ‘normal’ soil bacteria.
Soil fertility actually drops.
Crazy innit. Adding nitrogen fertiliser to dirt actually decreases its fertility.
And here is where the limestone content of rock dust works. It increases soil pH, the bacteria work better *and* one of the most important nutrients of all, phosphorus, becomes more available.
(Phosphorus doesn’t work in acid soil. Fertility plummets rapidly as pH falls)
Don’t tell these muppets though, the action of acid on limestone releases CO2!!!!
But in fact, if you have a strong healthy canopy of plant life covering that dirt, it slows the escape of that CO2 to the wider atmosphere. The plants create their own ‘CO2 enhanced’ greenhouse, with a few inches of the soil surface.
So beautiful.
But, if you/me anyone keeps coming aong and destroying that little canopy, what happens?
Does not the CO2 escape?
I hope and pray that I can hear some pennies dropping right now.
Remember my fix for California wildfires= build big squat compost heaps with any old organic material you can, add in pulverised rock then soak with water. (Joins up with that other thread about ‘Land Use Changes’ eh not?)
So, Mr Moonbeam. Instead of building a High Speed Train that joins nowhere to nowhere (is that about right), build a normal slow speed train to join Ventura County with Mount St. Helens.
Use it to import volcano mess.
Think of the (great) grandchildren. Start now and *they* might just have a nice garden to play in.
Here we are, a nice song for everyone, even alarmists, reading this.
Clear some space, give it 11 and throw some shapes.
(Slow burning at the start but give some effort. Your brain, heart brain and liver will thank you. They’ll stick a couple of zeroes to those 5 minutes and add that time to your life expectancy. Home-grown Dopamine tastes so much nicer that the sort alcohol and sugar provide. Give it a shot. What’s not to like? or lose?)

Alan Tomalty

In other words Do nothing Let mother earth keep doing what she is doing in the great recycling process. Any tampering and geoengineering just upsets the process and most importantly STOP picking on CO2 as the bogeyman.

Alan Tomalty

I think we should all listen to the late great George Carlin everyday


So turning farmlands into rock gardens will solve AGW? Well, actually that would work. Killing off all the people will definitely solve the ‘anthropogenic’ part of climate change. I wonder how they propose to solve the rest of climate change, or would anyone really care at that point?

Keith J

Far easier to iron seed deficient oceans.

Tom Schaefer


Bruce Cobb

What these schist-for-brains geoengineering “researchers” don’t understand is that not only is CO2 not the enemy, but we actually need more of it.


Wow, so all that lava rock I have used in landscaping around homes and businesses was good for the planet! Who knew?

Tom Schaefer

In the US, leave it to Yellowstone?


Problem w/Yellowstone is that 6 ft of ash deposited in the Dakotas is a bit much…


Moving lava rock is energy intensive with diesel heavy equipment on a massive industrial scale. Or does that not occur to non-engineering types?

Ed Zuiderwijk

Another solution to a non-existent problem. It may even work.

Mark Whitney

I thought Rube Goldberg was dead.


Is this another Al Gore Group company venture? The Green Rock Group. Or is it an Elon Musk project? The Re-Directed Meteor X Group.

David Cage

Anyone who acts on a theory, only sloppily reviewed by people already pre tested that they believe that theory enough to base the whole life’s work on it, with no external vetting allowed and certainly without an external quality assurance program funded to even 0.1% of the total spend is certifiably insane and pretty well every leader except Trump qualifies.


Scattered around the UK and Ireland (especially) are the remains of Lime Kilns.
These were used to heat limestone rocks to a high temperature which then were easily crushed into lime powder. The fuel was often turf – or commonly known as peat.
This was widely scattered on acidic/boggy fields to make them green and productive.
So there is nothing new under the Sun. Maybe they could recommission the abandoned lime kilns.

In The Netherlands geochemistry prof. Olav Schuiling introduced the idea of spreading crushed olivine rock on cropland as CO2 absorber in 2009. See

Leo Smith

Volcanoes burp out all the CO2 in the rocks , then emit rocks which, when crushed, absorb thee CO2 right back
Human burning of fossil organics burp out CO2 which, when the plants find themselves in a CO2 rich environment, absorb the CO2 right back
Plant Watercress! Save the Planet!

Gary Pearse

Okay, so 40% of the land surface is under agriculture ~60million sq km. so lets say we need 1mm of volcdirt (solid basis) on the surface: That is 60cubic km of dirt! That’s 180Gt of material to be mined, crushed and ground, to what, 100microns? Capex for a 1million t/y project would be ~$75M and opex ~$15/t.
Capex for a 10million t/y ~ (10/1)^0.6 x 75=$300M ; opex/t ~$10/t
Let’s say resources around world’s scattered volcanic regions (separate mine for each volcano) could support 10Mt/y for 20 years ~200MT of rock (volcanic areas are lived on so I’m thinking available with minimum disruption and that that CO2 problem would be solved in 20 years. That would take 900 operations at a capital cost of $270 billion + another 270 billion sustaining capital or $0.5 trillion and the fob mines op cost of product total would be $1.8 trillion or with profit $2T. Time cost of money, cost inflation on opex, payback of capital,(?), should conservatively double over the 20years – say a $4 trillion fob. all in cost.
Shipping to agricultural sites (the biggee) say ~$250/t avg, ~$45T.
What is the generally thought cost of doing nothing?

Gary Pearse

Is there a huge benefit to agriculture, or could be just spread this dirt anywhere? Make it the law in the Elite run world that you have to put volcdirt under all solar panels and wind farm acreage. Spread it on the Sahara. Make asphalt rooves with volcanic dirt coatings … roads, sidewalks, baseball diamonds, racetracks….If you are going to have a nutty idea why limit yourself?

Cost of doing nothing? About 1Trillion per year

J Mac

RE: Pulverizing volcanic rock and spreading the dust like fertilizer on farm soils could suck billions of tons of carbon from the atmosphere…
Why would anyone want to ‘suck billions of tons of carbon (CO2, not C!) from the atmosphere’??!!!
Why, Oh Why would anyone want to starve the worldwide flora… and all of the fauna that feeds on it, including humans? It is a suicidal, even genocidal proposition!


Crushing, shipping, and spreading the rock are all activities that would require energy – generating anthropogenic CO2. These idiots really can’t think past their narcotic pipe dreams, can they?


So, they discovered the Roman cement (not “Portland”), made out of volcanic ashes (Pozzolana) 20 centuries ago. Great.
And they suggest we massively cement the ground. Wonderful.
And they find an audience to spread the word. Without LOLing.
I mean, this is DHMO – grade farce.
I think I would nominate them for IgNobel.
Actually two. No, make it three.
One for these “scientist”. Another for those publishing and paying them.


Well a whole bunch of volcanic ash and rock just got injected into the atmosphere near the equator. Mount Singabung in Indonesia blew its top injecting ash over four miles up. Have not found info on the actual estimated volume but wondering about the potential impact for our summer this year.


Now you know the winter was cold this year, according to future generation CAGW “scientists”


A better use of that ground up lava would be in cement.

Steve Zell

If the goal is to improve the productivity of farmland, why not let the increased CO2 in the atmosphere increase the growth rate and drought tolerance of crops?
While volcanic soil is usually very fertile for plant growth, it’s very costly (and energy consuming) to move volcanic rocks to farmland far from volcanoes. For CO2 fertilization, it’s free–just let the wind blow the CO2 from where it is produced to farms all over the world!


There is no real evidence that CO2 has any effect on climate and plenty of scientific rational to support the idea that the climate sensivity of CO2 is zero.


I recently read about a study that claimed that in about 600 million years or so, the weathered rock on Earth would suck all the CO2 up, thus ending nearly all life on Earth beyond organisms living on sulphur and the like. How does this scheme get past the progressives and their precautionary principle?

“Audited field-scale assessments of the efficacy of CO2 capture are urgently required…” That is the big question, because hopefully it wouldn’t be so large as to offset the gains achieved by elevated atmospheric levels of CO2. The product is good fertilizer.
Mining it would probably be cheaper than manufacturing “normal” fertilizers. Here in Northern California, we mine cinders, as we call it, regularly to spread them on icy roads to facilitate vehicle traffic.
“…it’s very costly (and energy consuming) to move volcanic rocks to farmland far from volcanoes.” It is also costly and energy consuming to move produce from farmland to faraway cities. But it is done.
All in all, I am against the idea, because I would hate to see our mountains disappear so quickly.


In your opinion, adding yet another expensive component to the cost of raising crops and getting them to market, will have no impact on the price of said crops?