Episode 525 Rock Weathering

Professors David Beerling and Noah Planavsky are both experts in the innovative practice of “enhanced rock weathering,” which crushes rocks such as basalt and applies the powder to soil as a way of improving the quality of the soil and also capturing carbon dioxide from the atmosphere and sequestering it. Planavsky is not only a computer modeler but also the founder of a company that farmers hire to apply this technology. We consider the financial implications of using this innovation widely. For the video, audio podcast, transcript and comments: https://tosavetheworld.ca/episode-525-rock weathering.


David Beerling

Noah Planavsky

Ellen Judd


soil, basalt, rocks, carbon, farmers, weathering, question, canada, terms, countries, people, carbon dioxide removal, crops, co2, climate, agricultural land, model, capture, enhanced,


Ellen Judd, Metta Spencer, Adam Wynne, David Beerling, Noah Planavsky


          Enhanced weathering is a promising method of removing carbon dioxide from the atmosphere, according to David Beerling. It involves crushing rocks such as basalt and spreading them on degraded agricultural soils to capture carbon as the rock reacts with carbon dioxide in the atmosphere. The technique also offers co-benefits such as improving soil quality, increasing crop yields and reducing fertilizer usage. Where human societies grow the most productive crops, it’s always on the volcanic floodplains or the volcanic lowlands. In Italy, in the shadow of Mount Etna, they’re cultivating crops very actively around the base of the volcano, because those soils derived from basalt, and they’re highly productive.

       Beerling suggests that countries such as China, India and the US, which have large amounts of agricultural land, warm and wet climates and abundant basalt, are particularly well-suited to enhanced weathering. Some of the biggest emitting countries like China, India, the US turn out to be the countries that are best suited to capture co2 with enhanced weathering.


       However, Beerling notes that each country has its own opportunities and that Canada, for example, is still among the top ten countries that could benefit from the method despite its colder climate. Beerling’s research into enhanced weathering also highlights the need for a range of carbon removal techniques to address the issue of climate change.

       There is a need for a robust and defensible protocol for quantifying carbon removal. Beering and Planavsky note that there is distrust in carbon markets and a need for better measurement and tracking of the carbon removal process. They discuss two approaches to measuring carbon removal: using models or using empirical measurements coupled with a modeling framework. Planavsky is able to actually track the amount of carbon dioxide removal that has occurred. This is important because, as he notes, there is a lot of justifiable mistrust of carbon markets. He is using code that explains how this material captures co2 and changes the soil chemistry to try to design an ideal application scenario. The speakers emphasize the importance of being cautious and transparent about the carbon removal process, even if it is more expensive, and suggest that a framework that allows for emergent properties and clear metrics for uncertainty could build confidence in the process. Ultimately, the question is not whether enhanced rock weathering removes carbon dioxide, but how much carbon dioxide it removes, and the challenge is to develop a protocol that provides a clear and accurate measurement of this. 

       Ellen Judd raises questions about the potential of the initiative in Canada and the comparison of countries in a Nature article. David Beerling replies that the Nature article was a first attempt to use global maps of soils and climate to run a geochemical weathering model, and that the model could be improved with better simulations of carbon drawdown for agricultural land. He believes that Canada has great potential in enhanced rock weathering, especially when considering the movement of material from the US. Noah Planavsky adds that the feasibility of the initiative also depends on practical considerations, such as soil characteristics and transportation, and mentions that enhanced rock weathering should be thought of in multiple components, including agricultural lands and mine tailings.

       Beerling suggests that construction demolition waste could also be used in place of basalt, and notes that there are environmental impacts to consider, such as metal accumulation in soil and plant parts. On the topic of using silicates in China and India, Beerling suggests that construction demolition waste could be used as it is essentially calcium silicate, which can help regulate soil pH, capture carbon, and provide alkalinity. Planavsky estimates that there is a huge supply of construction waste in China and India that can give billions of tons of CO2 equivalents. The group also discusses the potential of Canadian wollastonite, a unique rock type that can work better in colder and less wet locations than basalt.

       Noah Planavsky and David Beerling discussed the potential benefits of using basalt, a rock dust, to improve soil health and capture carbon dioxide. They explained that the addition of basalt to soil can raise its pH level, leading to better nitrogen utilization efficiency and increasing yields. The researchers stated that basalt could be a relatively large component of soil amendments in India but a small component in the US and UK. However, they argued that farmers in the US could benefit from using basalt to cover costs and increase their bottom line, especially in the long term. They pointed out that nitrogen-fixing crops seemed to benefit the most from basalt, but they also observed increased yields in non-nitrogen-fixing crops.

       When asked about the financial feasibility of using basalt, the researchers explained that they cover all of the costs of delivering and spreading the rock dust, resulting in savings compared to lime costs. They also highlighted the need for a way to pay farmers who use climate-smart practices and capture carbon dioxide. They suggested that either a voluntary or government carbon market could offset the costs of transferring the tool and provide money for actual carbon dioxide removal. Planavsky further stated that larger corporations on the coasts, not farmers, should pay for the practice since they are making tremendous amounts of money but not keeping to their climate goals. Finally, the researchers expressed optimism about the possibility of implementing such a program.

       Enhanced weathering not only captures carbon dioxide but also improves soil health by replenishing trace elements and adding silica, which is important for healthy crops. The scientists noted that the cost of enhanced weathering varies depending on the transportation distances involved, but creative solutions like sourcing basalt from nearby states could reduce costs. They also discussed the idea of using crushed basalt to reverse soil acidification in Canadian forests, which could capture carbon and improve tree growth.

       The scientists expressed confidence in the efficacy of enhanced weathering and its potential to provide a second income source for farmers through the sale of carbon credits. The carbon credits would become more valuable if the price of carbon removal were to increase to $100 per ton, from its current level of $10-20 per ton. However, the scientists cautioned against being too trusting of methods used to quantify carbon dioxide removal and stressed the importance of basic mass balance and tracking methods to accurately measure the amount of carbon dioxide removed. Enhanced weathering not only captures carbon dioxide but also provides many benefits for soil health and farmers.


This is a machine-generated transcript that may contain errors. Do not cite it without checking for yourself by watching the video and catching any obvious errors. 

Metta Spencer  00:00

Hi, I’m metta Spencer. Today let’s talk about rocks. And if you don’t think that’s exciting, I tell you you haven’t learned yet. They’re going to save us. Good smashed up rocks are just what we need. And we have two guys who know how to how and why to pulverize rocks and what they can do for us. So today I’m, we’re going to go to Sheffield, England. And there we will meet Professor David Burling. David is a professor at the He’s the director of the lever, home center for climate change mitigation at the University of Sheffield. Hello, David, how are you?

David Beerling  00:44

Hi, very well, thank you.

Metta Spencer  00:45

Good to meet you. And we’re going to, I guess it’s new haven where a Yale University is located. And we’re going to meet Professor Noah Planavsky, who is an assistant professor of Earth and Planetary Sciences at Yale. And he must be a believer in rocks, because He has created something called the lithops carbon, which I think is a company that uses pulverized rock. Hello, Noah, how are you?

Noah Planavsky  01:16

Great. Thanks for having me.

Metta Spencer  01:17

It’s good to meet you. Okay. And I’ve just found out that you folks know each other already. And in Winnipeg is my I guess professional in a way professional colleague, in a sense that she’s an anthropology professor retired and I’m a sociology professor retired. She’s Ellen, Ellen Judd, Professor Ellen’s, the University of Manitoba in Winnipeg. And we she’s sort of my co chair of this, but it won’t take much chairing. So far, they’re just two speakers, we could be joined at any time by some other members of the Canadian Pugwash movement. Because the whole project this mean Monday is every Monday for a while we’re having a talk show about one of the one of six potential interventions that could be made, that we think that all together would have a noticeable impact on on climate on the planet. And they’re things that can be done by Canada and by Canadians, within about at least started within about five years. That’s my theory. That’s why I picked them. And one of those things is, has to do with how we get co2 out of the air. And one of the ways is the way nature does it does nature uses rain, which when falling picks up co2 and becomes kind of fizz water, carbonated water, falls on rocks, combines makes compounds that do things for the soil and flow into the ocean and get eaten by shellfish and make made into shells. And then the shells fall to the bottom of the ocean and stay there for a million years or so. So I thought well, yeah, I’ve heard that people say we could speed that up by smashing the rocks and making them into a powder, which has more surface more surface area than regular rocks. And maybe they can do more of it. So that’s the theory. And I believe we have two proponents of that theory, because Professor Beerling did the first and most, I presume, most widely cited research on what that would be like doing it in various countries, and how much we can, how much co2 We can take out of the air and so on. So let me ask you, David, since you kind of started, you’re the ringleader in this movement at let me ask you to give us an overview of what you know, what’s this all about? I’ve done my poor layman’s introduction. Now you you give us the real truth.

David Beerling  04:06

Oh, well, just to take a step back. I mean, I think you know, as we saw at COP 27 in the world, isn’t doing a very good job of dialing down emissions, or taking steps to dial down emissions, they’ve totally ducked the whole issue. And, you know, ultimately you do need to reduce emissions. But that’s not enough anymore, we need to figure out ways of taking carbon dioxide out of the atmosphere. So we need solutions that are going to help do this. And I think enhanced weathering is one of the most promising ways in which we can take carbon dioxide out of the atmosphere. Because you know what I think one of the things that sells it for me is that it has a number of CO benefits for the agricultural system. So it can improve soils can improve crop production, can reduce fertilizer usage, which are all very critical issues at the moment. And I think you know some of the other needs that are on the table, they’re great, we’re going to need a whole collection of different carbon removal techniques. What’s unique about enhanced weathering as we’ll get to later on aspects is that it does have these co benefits which can attract in the agricultural sector. But you know, very simply what it amounts to is really just adding, you know, as you said, in your nice introduction, a very, a lot, you know, crushed silicate rock, volcanic rock or basalt, which is very abundant. And, you know, by crushing it, you increase the reactive surface area, and then you surface till it into the land or surface, apply it. And then the corrosive nature of the soil water, the water and the co2 forms a weak acid breaks those rocks down, assisted by microbes and the activities of roots. And then as it released as it breaks the rocks down, it captures atmospheric carbon, and either stores it in sort or washes it out into river systems into the surface ocean. And these are, it’s a natural rock. And these are natural reactions that have been going on for millions of millions of years. And if you think about where human societies grow the most productive crops, it’s always on the volcanic floodplains or the volcanic lowlands. So if you go to, if you go to Italy, in the shadow of Mount Etna, they’re cultivating crops very actively around the base of the volcano, because those soils derived from basalt, and they’re highly productive. And I guess what we’re saying is that’s one way to think about it. But another way to think about it is this mind those rocks and put them on our degraded agricultural soils, capture carbon, restore our soils and improve our improve our yields.

Metta Spencer  06:50

Sounds good to me. But they’re sure a lot of people who are going to think of everything that can make me critical, absolutely.

David Beerling  06:58

That is the scientific process, right? You put your idea out there, and then the community tries to knock it down. That’s how, that’s how science progresses.

Metta Spencer  07:07

Yeah, that’s true. Okay, now, but you also found, you did a comparative analysis of the conditions. I don’t know whether the soil conditions or maybe other things as well, in a number of different countries. And can you came up with some statements about where this procedure would work the best, or comparing some better than others? I maybe you can tell us about that. What was your effort to, to make these comparisons?

David Beerling  07:43

Sure. So the work that we did a couple of years ago was really trying to figure out, you know, which nations would be really good at doing this, who would benefit the most. And really, to do this, you need to eat a warm climate and a wet climates, you need, you need warmth, and rainfall to drive the chemical breakdown of the rocks. And you need large amounts of crop lands. And you need you know, almost need to be, you needed a good supply of basalt, that’s not too far away from your crop lands, it needs to be sort of co located. And when you do all the calculations, you know, what you find is that some of the biggest emitting countries like China, India, the US turn out to be the countries that are best or most suited, I should say, to capture co2 with enhanced weathering. And that’s one of the reasons that I’ve just said that have large amounts of crop lands, warm climate and wet climate shows accelerates the weathering, and, and large amounts of basalt as well. So really, I think our study was the first one to kind of try and do an initial assessment by different nations around the world, figure out who the winners might be. And so we sort of came up with a table of top 10 nations. Really, I think the take home was that, you know, each country has its own opportunities. I think what struck us was that, you know, the three or four biggest emitting countries in terms of their fossil fuel, carbon emissions, were the ones that were most able to deploy this to capture carbon. And, you know, you could say, I mean, I should say this carefully as somebody that lives in the country that started the Industrial Revolution, more co2 into the atmosphere, per capita than any other country. But you could say those nations that have added most, or that are missing the most, they have the moral kind of responsibility to address it first.

Metta Spencer  09:37

Okay, that makes sense to me. But it’s a little initially discouraging, because my project Well, the thing I’m proposing is that we try to get the Canadian government to sort of urge people on and create some incentives to do some of these things. And what and Canada is not a warm country. So I noticed that we were not on your list of the top three or four countries that would benefit from using this technology? Is there still hope for us that we can benefit from it? Or?

David Beerling  10:10

Oh, yeah, absolutely. I think you are in the top 10 If I recall the paper correctly, and you’ve got large amounts of agricultural land. And admittedly you have very cold winters, but you also have quite warm continental summers as well. You have sources of rock different sources of rock. So I think there is great potential for more detailed analysis. And you also sit on the border of some of the some of the states in the in the US that are producing bustles. So there’s scope for you know, exchange of basalt from the US to Canada to promote carbon drawdown.

Metta Spencer  10:45

Okay, yeah. All right. And okay, we’ll come back to some of the other questions that might occur to me now. But let me ask Noah, who created an organization called Lithos Carbon, which I gather it goes out and actually spreads dirt or rock that some things? Is that right? Tell us about your work?

Noah Planavsky  11:04

Yeah, well, a lot of my research historically was on trying to understand or is history and trying to understand how the carbon cycle works. What controlled past atmospheric co2 concentrations, so many of the tools that we use to understand or as pass, actually, including some of the computer code that we that we write actually is equally applicable to understanding how we can mitigate current atmospheric co2 concentration. So in some ways, it seems, seems like a big jump to move between Earth’s history and move into into soils. But in many ways, the same, the exact same tools are equally applicable to both. And yeah, in terms of litho is a is a company that is is trying to have, which I’m with, with several other people trying. I’m a co founder, along with several other people, we are trying to deploy the idea of enhanced rock weathering, at scale. And the idea from that is in part because of research that that David’s done, other groups have done that we’ve done, we think that it’s really at a scale, where then one of the next things we need to evaluate is not only if this works in research plots, but how this is going to work on large scale working farms. And it’s a different way to get you learn different aspects when you do that. But it’s I think it’s the jump between kind of the scale of things that David and I had already been working to move to getting this out into the into the world, in some ways is a is a relatively small step.

Metta Spencer  12:46

I don’t understand code whatsoever. So I was little intrigued by your notion that as in code would work to explain history and something about current technology. So we can talk, you can answer that or you can, yeah, tell me explain that first.

Noah Planavsky  13:06

Yeah, well, really, what we want to do is the basic idea of what we’re trying to do is put down an amount of crushed material. And in most cases, we’re taking waste from already existing mining operations. So we’re taking that waste material and putting it in a farmer’s field. So foremost, what we need to be sure is that we’re actually creating conditions that improve yields for farmers want to make sure that we’re also doing this in a way that’s as efficient as possible. So you can use code that understands how this material captures co2 and changes the soil chemistry to try to design an ideal application scenario. Or we can use if you think about it scaling out from a field, you can think about it just as David was just talking about, how can we use you can’t go around and explore everywhere in the world with empirical studies where we want to do this. So you can do that by using models that take climate conditions, take soil conditions, take information about the farms, and run a model to gauge how well this is going to work.

Metta Spencer  14:15

So when you’re doing historical analysis, you would you would be trying to guess at the climate conditions of a certain historic geo historical period, and plug it into your model and use it in the way same way you would today’s. prac practical work, right?

Noah Planavsky  14:40

Yeah, that’s one way to think about it. It’s It depends really what the question is. Basically, if you if you have if you have a model code that is designed to track carbon cycling, you can really use it in many different ways. So we’ve had that from You know, some of the same packages, we’ve used to understand very early Earth history, and even how, and even how exoplanets will maintained, there will potentially be habitable or not. So the idea of and the basic idea behind all of this is chemistry and physics don’t change. And models, mechanistic models are grounded in chemistry and physics. So you can, you can, if you understand, if you understand how a process works, it actually can, you can use the framework to be able to answer a wide range of different questions.

Metta Spencer  15:37

And your company does things like contact mining people to find out where you can get some of their tailings and contact of farmers and ask where they want that sprinkled? And then you get a machine that does it? And is that the kind of thing your operation does? Or, you know, what do you do?

Noah Planavsky  16:01

Yeah, so there’s really two aspects, if you want to think about deploying this at scale, you there’s, there’s kind of two aspects that you have to do. You have to arrange for the material to obviously be deployed on the field and deploy and make sure that the materials are not going to have any negative impacts on the farmer have quality control on that, and, and obviously, design a strategy that will work for the farmer and and, like we’ve seen in our trials, make sure that actually increases the yields for the farmer. The second aspect is, besides sorting out the actual practical aspects, we want to do this to capture carbon. And what we’re actually doing in that case, as this ties into markets, economic markets, that that are tracking carbon, you have to be able to show you have to be able to actually track the amount of carbon dioxide removal that has occurred. So that’s the other aspects that that we’re, we are we are working on so

Metta Spencer  17:04

well. That is obviously one of the things that we that Ellen and I will want to ask you. How do you know how much your How much co2 You’re capturing? And how long it’s going to stay where you put it? And why should we believe you? Because if you’re a salesman, your company has to convince somebody that it’s to their advantage to use this material, and that they’ll get money out of doing it. So tell me and David, do you? Do you have anything to say about this whole thing of approving the effect of this, of using this technology? That’s, I’m sure the next thing we all want to know is? Are you sure it works? And why? Prove it to me?

David Beerling  17:53

Yeah, yeah, I mean, there’s a couple of interesting things there. And I think unlike reforestation, where you grow a tree, and you can measure the amount of carbon in a tree. And as weathering poses its own challenges, because it’s quite a complex set of geochemical reactions. And so all you need is figure out a way in which you can synthesize the net result of the reactions, that gives you a number of how much carbon dioxide you’ve moved. And there are a number of online carbon removal companies now to sell carbon credits that are realized, actually, if we want enhanced weathering in our suite of carbon credit options, then we need a protocol that is robust and defensible, for how we’ve taken comm dioxide out of the atmosphere. I think what that’s done is really kind of focused the minds of academics thinking about, okay, so how do we go about developing robust ways to quantify carbon removal? I think you know, Noah’s been doing some really nice work in this space, where you actually analyze isotopes, and we measure elements in soils. And that’s a slight shift from rather than trying to look for the reaction products in the soil solution that drain out into the river systems. You focus on how much basalt was actually dissolved in the soil. I think that’s your kind of really big step forward, because it kind of gets through this barrier of trying to measure these fluxes in the source solution that are difficult to measure that don’t drain when it’s dry, or that get diluted as what you really want to do is go after the fundamental mass loss of basalt that you’ve added to the soil. Now, I kind of expand on that a little bit.

Noah Planavsky  19:36

Yeah, I think well, in terms of one of the things that’s I think if you look at there’s a lot of distrust in carbon markets. And I think anybody working in this space is okay, acknowledging that the way carbon markets have developed so far there’s been a bunch of mistakes. People should be wary of many of the things that are happening on carbon markets today. So if we want to have, if we want to try to quantify carbon dioxide removal and put $1 price on it, or any, any currency you want to guess not to be to US centric, if we want carbon credits to be truly fungible, we have to do a better job of what we’ve been doing. And that should be our starting point

Metta Spencer  20:20

not where you have to do a better job of actually measuring of quantity of stuff in the soil after before and after you put yourself in there

Noah Planavsky  20:29

tracking all aspects of the process, right. So we could we could spend the whole conversation just about where we could do a better job in any form of carbon dioxide removal. And there’s two basic ways that that probably won’t be the most fun way. So just to spend the conversation just focusing on enhanced rock weathering, there’s two, there’s, there’s two basic approaches to it. You can  do this with models. Or you can do this with empirical measurements coupled to a modeling framework. And, and if you make empirical measurements, it’s more expensive. But it’s obviously a more robust way to do it. So we have a little bit of take different take than some other people are doing that. I think right now, especially as this is a new field, the most important thing to do is to be as cautious as possible. And even if something is more expensive, make sure as we’re beginning to understand this process, do the more expensive thing, get as much information as possible, and be as transparent as possible about what you’re actually recording. And what are the uncertainties associated with each step of that process? Well,

Metta Spencer  21:39

presumably, then you check it against your model and see if they if they match.

Noah Planavsky  21:44

So it’s yes, at some point. Ideally, you can reduce your impure cost of making measurements to try to do that, and have the model play more of a role in predicting how much carbon dioxide removal has occurred. I think that’s something we want to move to in the future right now. I think if if you’re asking me how to how do you convince people that you can actually track the amount of carbon dioxide removal? My simple answer to that, and obviously, obviously, part of that, because I’m a geochemistry makes measurements is I will show you do chemical measurements that are directly tracking the process.

Metta Spencer  22:21

And you’re confident in your own your own procedures, you believe that you’ve that what you’re finding fits what we hope you find that you actually are able to reduce the carbon in in our atmosphere by using this technique.

Noah Planavsky  22:39

Yeah, so if you taking a step back what you know, without question, it’s not if this really if this removes carbon dioxide, or if it doesn’t, it’s always going to remove some carbon dioxide removal. The real question is, how much carbon dioxide? Does it actually move? And how certain can you be for that? And so in terms of the way I view, confidence, I think it’s shouldn’t be where we’d ideally like to move is to a system where it’s not something about my confidence and kind of a gut feeling about it’s how do you how do you provide a framework where the uncertainties can be emergent properties from the framework that you’ve produced? So if you’re making a measurement in one place, right, there’s spatial variability? How do you demonstrate by multiple measurements, the amount of uncertainty you have in spatial variability in your signals, for instance, those are sort of things that allow us to build confidence with clear metrics, and have uncertainty be something that’s not an abstract concept, but something that has clear guidelines. And that’s where I think we really need to go to have people be very confident about the process.

Metta Spencer  23:51

Okay, well, I have questions, but I imagine that we have the Ellen does, too. So I’ve been hogging the mic. Ellen, do you? Do you want to interrogate these men first?

Ellen Judd  24:03

I certainly have some questions. And my interest is along some of the same lines as yours. Both with this capacity to have the initiative to go out and start projects in North America. That’s really exciting. And I was especially intrigued I spent last night reading this wonderful Nature article that looks compare various countries. And I thought that was really interesting. You anthropologists are always interested in cross cultural things. And Canada is in the mix. And China where I worked for a long time, is there are two so I had a couple sets of questions. And perhaps I’ll start off there because it relates to this issue of how we deal with things globally that’s in the forefront of our or consciousness with cop 27. Right now and, and would be anyway. You there too, I guess dimensions of this. One is the targeting of the four countries that you think are most promising China, India, the US and Brazil. And I think that’s fascinating. And I’d like to pursue that. But perhaps the other thing that struck me was Canada. And in the same sense of its it struck matter, because we look like an outlier in a couple of ways that are a bit concerning. And I was glad to hear that you didn’t think that was hopeless? And a lot of Canada I thought might be it’s obviously the North is not prime agricultural land. And if a lot of the problem is, resides simply in the cold that’s just the way it is. But are there other factors to think about, I noticed on the on the first comparative graph of a number of countries, Canada was really an outlier in terms of the projection not just flattening out but even beginning to decline. And I didn’t know what all the factors involved were, I was hoping it was in Arctic country. But in terms of other kinds of issues, where does that stand?

David Beerling  26:40

Sure. So I guess the thing just kind of bear in mind with that paper is really a first look, before we’d come along, we didn’t really have the numerical simulation tools to start doing this. And it was really the first attempts using a global map of soils and climate to run a sort of geo chemical weathering model. And then combine that with the underlying transportation networks for moving the rocks around and figuring out how much carbon was admitted, and so on. So it’s quite a detailed analysis, but it’s really the first time that had been done on nation by nation basis. And I think, you know, with respect to Canada, I think there was probably a lot of potential what we’ve, what we’ve been doing since then is sort of developing the next generation model, which allows us to simulate carbon drawdown in more detail. So you can, you can, for example, pick a particular country and then figure out where all the sources of rocks are, and then do simulations over the next 50 years where you can continue to look for the best agricultural land where you put your rock dust down, in order to optimize your calm dioxide removal. And so I would, I would view that the numbers in that paper as a kind of lower bound, I think we can probably do much better for Canada if we did a kind of focused, Canada centric study with our next generation set of models. So I mean, we have been targeting the US next in the hope that we might, you know, get the Biden administration’s attention on that enhanced weathering. And, and what we’re finding is actually what I’ve just said, Really, the numbers are looking very promising for doing when you do dynamic simulations of carbon drawdown for agricultural land in the US, you know, the numbers add up towards point four point half a giga ton, which is actually quite substantial because the Biden path to net zero calls for half a giga ton of carbon dioxide removal by 2050. Our simulation so you know, you could get 70% of that from just from enhanced weathering without having to use industrial processes, direct air capture or bioenergy with carbon capture my 100 shares, and now we haven’t done an hour haven’t done a detailed analysis of Canada yet, because these tend to take quite a long time to do these sorts of nations specific studies. My hunch is, you know, Canada could probably do probably do quite a lot better, especially if you start thinking about movement of material from some of the kind of Northern US passport producing states across the border. I suspect, I mean,

Metta Spencer  29:18

let me ask you, again, you say half a gigaton for how much? What country or is that the whole world if half a gig

David Beerling  29:33

I was talking about the US specific study that we’re working on.

Metta Spencer  29:39

So what US alone could remove half a giga ton, what per year

David Beerling  29:44

by 2050 by 2050.

Metta Spencer  29:47

That’s not very ambitious. Step it up fellas. We got to take out 20 or 30 gigatons a year, starting tomorrow.

David Beerling  29:59

Yeah. For sure, absolutely. I mean, you know, I think the most important thing is if you’re omitting 50, or 60 Giga tons a year and co2 in fossil fuel emissions, most important thing is you get those emissions down. But even if you can get,

Metta Spencer  30:15

I mean, we know that’s not enough, you said some of yourself, They say the people who were at COP 27 say that for the first time to people there were talking seriously about climate restoration, which is, you know, the polite word for geoengineering, which is what you guys do with we actually use the blunt language on? Sorry,

Ellen Judd  30:42

if we would assume that one of the reasons why you’re looking at countries is that that’s the basis upon which you can get data available, because it’s packaged that way. And what’s dealing with various political realities. If we’re looking at it from a natural science point of view, could one expect to get somewhat different results for Canada, if we were practically looking at the large agricultural reasons, regions, the prairies, for example, the prairies that are vast areas of agricultural land, and we didn’t have to worry about land that was too cold or enormous transportation distances? Or if we took out those factors, would it be reasonable to say that this would be something that can be done on a regional basis in Canada, in Canada? Or am I missing other factors that, that are making us not look like the ideal? The ideal candidate for this?

Noah Planavsky  31:50

Yeah, so one of the one of the things it’s there’s two really key aspects to keep in mind and in terms of the feasibility of various there’s kind of the practice very practical considerations, which are a lot of it is a very mentioned truck transport. But the soil characteristics also make a really big difference. So one of the a lot of the a lot of the prairie agricultural areas, we have kind of we have canola and wheat actually are not ideally suited for this. And in terms of the soil characteristics of it, so many of the areas in the in the East work better than the prairie lands, you’re starting out at a at a very high soil pH and in many of those regions, where they’re not as ideally suited for it. So I think, and as but one of the things is, as we kind of, you know, as, as we David and I get excited, and other people working on this, get excited about individual countries, is you learn you learn areas where there’s where there’s obvious targets that have really key co benefits to the to the farmers and are practical, and can deliver large amounts of, of carbon removal on that. The other thing I would add on the on the Canadian front is David and I mostly focused on basalt, because it’s incredibly abundant. But there are other mineral as rocks and minerals that can be used in this. So one of my one of my favorite companies right now is company called Canadian wollastonite. That’s has, it’s not as much material available as basalt. So it’s in terms of a global impact. It’s a relatively small scale. But in terms of thinking, thinking about what could be done in Canada, they are a company that can lead to millions and millions of tonnes of carbon dioxide removal in in a unique rock type that actually can work better in colder locations in less wet locations than basalt. So there’s lots of things you learn by looking into more detailed maps and some of those also when we talked about as enhanced rock weathering, it should be noted that the vast majority are talking about these big numbers, things like billions of tons, it’s going to have to be resolved. When you focus on individual areas. There are companies like Canadian wollastonite that could make a huge impact in local regions and and yeah,

Metta Spencer  34:12

but we also have a lot of mine tailings. I don’t know where they are. I tried to, you know, Google and try to find out where all these piles of rocks remain tailings are located and I can’t, but I understand that there’s there’s a lot of it if we decided to dig it up and use it. It is, but it isn’t. It’s questionable. I mean, it contains toxic materials and stuff. So how much of it could you actually use from other mine tailings that already exist?

Noah Planavsky  34:46

Yeah, a lot of the strategies in mind tailings are a little bit different instead of trying to move the material to agricultural lands, in many cases, it’s taking the mass of mine tailing piles as it exists, and actually trying to drive carbon capture in place in those settings, and there are multiple companies, some of which are Canadian based that that are trying to do that as well. So I think that should be enhanced rock weathering should be thought of as multiple components and agricultural lands are one that they were particularly focused on again, because there’s, there’s so many obvious co benefits to farmers. And it’s something where and it’s something where there’s, there’s already the infrastructure in place to really rapidly scale this up.

Ellen Judd  35:35

So the discussion of different kinds of rock that can be used for this, that leads me to one of the other things that I found particularly interested in the reading I was just doing, which was the reference in addition to Basant, to usines, silicates, and particularly using those in India and China. And that seemed to raise some other kinds of very interesting questions I’d like to hear more about, because it is so important to bring those two countries in, in terms of their agricultural capacity, and thinking beyond, you know, the Global North. At the same time, one of the things that you’re referring to, and that I really interested in hearing more about is the question of their environmental impact. And whether they, you’re whether one can, in fact, use those sorts of materials for agricultural purposes. And whether they’ve been environmental, we, we had a question also offered in advance, asking about environmental studies. And I was wondering what the state of the picture is, right now on the potential for using large scale silicates.

David Beerling  36:49

You know, one possibility that we sort of put forward in that paper was the idea. You could use construction demolition waste, which is basically, concrete cleaned up concrete, because that’s basically a calcium silicate. So it’s just which also produces alkalinity. So it helped with soil acidification. And so conceivably, you could spread that on, on wasteland or farmland, you could capture carbon and regulate soil pH with it. There aren’t many studies that have done that we did, we are undertaking a field trial in the in the UK, trying to investigate that. That’s, that’s one side of it. The other side of it is, there’s actually a company already that’s kind of seized on this idea in Ireland called silicate. And they took a slight twist on the idea, which was the realisation that when people order ready mix concrete, they always order too much. And so they want to do is, is actually recover the excess material, take out the pebbles and the rocks, and then make like a cake out of it, and break that cake up into a powder and spread it onto the land and use it as a substitute for lime. So it’s kind of issue when you put these ideas out there in the literature, it’s interesting to see how they grow in which directions they go. And in terms of the kind of environmental impacts, it’s obviously crucially important to be aware of those. There’s a whole different suite of them. There’s a sub supply chain environmental impacts that are well understood in terms of the mining, and so on, so forth and transportation. But then there’s also the environmental impacts of adding this material to soils. Do you see metal accumulation of soils do you see metal accumulation in the, in the plant parts. And we’ve been running in the US cornball with College and University of Illinois some of the longest enhance weathering trials in the world. And we don’t see increases in heavy metals at all, in the soils or in the edible parts of the plants, which kind of ties in with what I said at the beginning, which is, you know, if it was bad for people, then, you know, human societies wouldn’t be cultivating crops on the flanks of Mount Etna for the last 400 years. So I think I think he’s reassuring, but you absolutely have to be mindful of that. And you can’t take it as a given you have to complete due diligence with monitoring all the time. So again, Isabel

Ellen Judd  39:26

was quite fascinated with that, partly because, you know, some of what’s happened in China for several decades has been massive construction everywhere. And then because some of it doesn’t meet contemporary standards and was rather rushed at the time. A great deal of that has been torn down. So you would in fact, be able to get access to quite a lot of concrete that’s been demolished. There’s be a very large supply of that. And I wonder whether you This would be on such a large scale that I think would be worth looking at. Maybe somebody’s doing that, and if not, I would encourage you to find some Chinese colleagues to work on. Yes.

Noah Planavsky  40:15

If you take just estimates of the amount that is produced in China and India, which are going to be the absolutely the largest sources of construction waste, it can give you billions of billions of tons of co2 equivalents.

Metta Spencer  40:33

Let’s talk down because one of our other projects is the use of carbon negative concrete. And they also have their eye on using this demolished concrete. And I worried about what they’re going to do when they run out of the calcium. But if there’s that much of it around, maybe it’ll take a few years. Before we have to worry about that.

Noah Planavsky  40:56

I mean, certainly in its in US UK perspective, it’s going to be a small component of the of the overall material we want to work with. But in India, it could be a relatively large component of what is needed to kind of bring soil to an ideal ideal pH.

Metta Spencer  41:16

One of the things we do now is, this is a live show. And people can call, but type in questions. And my assistant Adam watches for these. So Adam apparently has retrieved a juicy question or so, Adam, you want to put it to these gentlemen?

Adam Wynne  41:37

Sure. So we have several live viewers right now. And one of them is a farmer. And they’re asking if you can speak to the researcher have evidence that this will result in increasing yields, because the cost of the stone and the delivery is quite significant. They love the idea of carbon reduction. But the bottom line and the finances are what’s very important to them when operating and running your farm.

Noah Planavsky  42:04

Yeah, I’ll start in the follow up to talk about the longer term ones. So one of the things I would say from it’s absolutely something where the way I view this and one of the reasons they went to the question of why did why did you want to try to commercialize this, instead of just studying this an academic setting. One of the things I think this is actually provide a way to cover to actually, you know, cover costs for farmers and actually increase the bottom line farmers so on a farm with my, with my sisters in the Midwest, and it’s hard to make money on a farm, even if it’s, especially if it’s not a massive farm. So in terms of the strategy we’re taking for this, we are covering all of the costs of delivering the assaults and spreading of the basalt. And what that ends up being is savings relative to lime costs. Whereas I don’t know how much the individual farmer there’s paying, but where we’re in Wisconsin where I’m from, it’s going to be somewhere around, you know, 50 bucks a ton to put lime down. And it is something where we know, keeping appropriate soil pH gives you better nitrogen utilization efficiency. In many cases, there’s obvious benefits to lining, they come with a cost if you switch to basalt, we can give you the right soil pH, you’re saving money not saving money instead of spending money.

Metta Spencer  43:31

So you think it’s actually to their advantage, and you can show that it’s, it’s a good investment.

Noah Planavsky  43:38

Yeah, David, you want to actually speak to long term yields, I mean, we have one off yields, but the the, the longer term, and

David Beerling  43:46

so so we do see a consistent increase in our in soil pH. So one of the problems with farming with fertilizers that acidifies the soils intensification of farming over time acidify soils, which is why farmers have to add in a crushed limestone to reverse that effect. And you know, as Nova sand basically, if you add basalt, then you can raise your pH, but you capture carbon at the same time. So it’s a kind of win win. What we’re seeing in our long term trials is increasing yields. So we’ve been growing it in the Corn Belt, near Illinois. So these are typical Roy’s rotation of corn, one year corn, the next year soy, what we find is that you get increase in maize yields the first year on the order of you know, 10 or 12%. And it kind of disappears the next year, and then you get a big increase in soybean yields. And that kind of fits with the chemistry and of what’s going on in the biology of what’s going on because the soybeans are nitrogen fixers, so they have nodules in the in their roots that hosts the nitrogen fixing bacteria and they should Romney acidify the soil. And that helps break down the rocks and release nutrients that the microbes need to fix more nitrogen. And so what you’re doing really is what we’re seeing in our field charts, particularly is that nitrogen fixing crops seem to benefit most from the bustle. But we’re also seeing it in non-nitrogen fixing crops as well. It’s a pretty exciting set of results we’re looking at.

Noah Planavsky  45:28

Yeah, and I guess as the last last one question. I think one of the strategies of the way I ideally, see this happening, and this is a very US focused framework, but in many ways, I think many of the many of the, I would like to see enhanced weathering be a way to bring money actually, from the coasts into the center of the country has tremendous capability of farmlands to actually remove carbon. And the people that should be paying for that aren’t farmers, it should be it should be larger corporations on the coast that have that are making tremendous amounts of money and not keeping to their climate goals, paying to have a more stable income for farmers. And that’s something that I don’t I don’t I I’m not on I’m unapologetic about having that as as my view of who I think should be paying for this practice.

Metta Spencer  46:21

Okay, that brings us back to the whole question of carbon markets and the carbon offset payments and that sort of thing, which I don’t understand very well. But clearly, if you have two different beneficial effects of sprinkling this spray, or whatever you do with this rock dust, and that is it improves the soil and the productivity of the soil and the quality of the food you produce, etc. At the same time, as you grab and sequester carbon, then you should be, you know, the farmer should get some income from both sources, somebody should be paying him for the services doing in cleaning up are the greenhouse gases, and somebody else, the consumer will presumably be paying him also for the food he produces. So, you know, is there some ideal balance of incentives that maybe the Canadian government could offer such and such a number of dollars per acre per hectare? For to a farmer? Who is an early adopter of your technology? You know, or something like that it? Do you have any thoughts about how to pay for this thing? Because it’s going to cost a heck of a lot of money, especially if, if you scale it up on the level that I hope you will be doing? In other words, I thought you were very modest in in hoping  to be able to remove half a giga ton by 2050. In the US. That’s, that’s not enough. We got to start right away. And we and one way would be just pay people to do it. If you can, with good conscience tell people, yeah, it’s safe, you’re not going to ruin your soil. And everything is going to be okay using it. And here, try it.

Noah Planavsky  48:17

Yeah, I can start on that. Well, since my sister’s a farmer, him or her? Let’s not forget, let’s not forget, all farmers are no longer males. But, um, yeah, I think the way, the way I think of this is basically that the farmers should want to do this and should be excited about the program, because it increases the yields. And people that are helping them do this have to have an understanding of how that process works, or you’re not going to help them increase their yields. But on top of that, is basically whether it’s the voluntary market, or whether it’s a government program, I think there should be payment that offsets the cost of transferring the tool and gives money to to farmers for the actual carbon dioxide removal. And one of the things that government programs have a way of dealing with the voluntary markets don’t is a way of kind of ensuring that this happens at broader scale. And there’s a way of spreading the costs around to different deployments, where in the voluntary market, it’s going to be you focus in areas where this is most cost effective. And that’s not going to necessarily give you the largest amount of carbon dioxide removal. So there’s pros and cons to thinking about both of those. And that’s one where I’m not going to offer my opinion on which of those is, is I think most beneficial but but either way, I think what the what do you feel strongly about is that absolutely it’s the farmer should want to do this for obvious reasons. It’s increasing, making their farms actually more fun. There needs to be a way to pay people that are doing climate smart practices in farms on farms.

Metta Spencer  50:08

Can you think there will be?

Noah Planavsky  50:11

I? I am an optimist, so I’ll leave it with that statement.

David Beerling  50:20

Yeah, I agree with no, you know, payments to do it is good. You know, that’s what we need to kind of kickstart it, but ultimately, we want and the market side of it, you want one price of carbon removal, that’s, you know, $100 a ton, at the moment it’s 10 or $20 a ton. And so this will generate a second income source for farmers. I don’t work in acres and flow, but five tonnes per hectare, then, if you’re getting 500 If you’re selling those carbon credits at $100 a ton, that’s 500 $500 a hectare, that you’re getting on your land each year for doing this. And that suddenly makes it you know, with a with a carbon price remover, that that sort of level, certainly makes it quite attractive option that kind of brings in a second revenue stream for farmers.

Metta Spencer  51:17

Okay, Alan, do you want to have another question? Or should we go back to whatever Adam may have for us?

Ellen Judd  51:24

I could follow up on a bit of this because there was this other question that we heard about selling carbon offsets. And I guess that is something that somebody a question that was provided for us by Peter Fiekowsky where he was asking how this market would work at a later stage, and perhaps I’ll just read his question. How would they finance removal of the million tonnes of legacy co2, they probably plan to use carbon offsets to remove some co2 caused by burning fossil fuel. Now, selling offsets is arguably good for the economy, but only prolongs fossil fuel usage. After fossil fuel usage is over, optimistically speaking, I guess, can these methods be financed to actually restore the climate, if the cost is $50 per tonne of co2, someone needs to commit 50 trillion to this half the world’s GDP. Who would likely do that, or even a 10th of that

Noah Planavsky  52:31

we’re trying to move to not only to meet climate goals, not only net zero, which means removing all of our fossil fuel usage hard to abate sectors, and moving to some ambitious targets in terms of what we do with nitrous oxide methane emissions. And on top of that, to meet our climate goals, we need to be removing carbon dioxide from the atmosphere. So that is that is no matter what why we’re talking about, about carbon dioxide removal. And so in terms of the ways the scale of this and how it ties into things, one of the things that if you’re thinking about the scale that we’re talking about, it’s very difficult to have this be tax credits. So you will, one of the things and just in terms of the scale, we really need to surpass what it would be in terms of credits. I think that’s why you want to think about it in terms of an actual cost of carbon. And in terms of the very long term use of this if it’s a if it’s at a case where we are, we are at our climate goals were at zero emissions, but we still want to move to something that is is reducing human suffering is better for ecosystems, stability, etc. There’s going to need to be government programs to kind of have carbon dioxide removal and think agricultural settings in many cases which agricultural practice today are heavily subsidized, make sense to focus on off takes for the long term, carbon dioxide removal in that as David and I are stressed bunch of times. There’s so many reasons why this makes sense for soil health. There’s so many reasons why this makes sense for farmers, besides just the carbon dioxide removal aspects that so if you think about something that if we can have high confidence in the amount of carbon that we’re removing from enhanced weathering, it makes sense relative to many other practices because it is also providing a key a key social good.

David Beerling  54:29

I think I think I was covered that nicely. Nothing further to add model.

Ellen Judd  54:36

I was reading the Nature paper. There were two places where Canada seemed to be an outlier. One was the one we’ve already discussed. The other was the cost of doing this. We seem to have the highest cost in your sample of many nations. Do you have any insight into why that’s the case and I how we might think about doing something about that.

David Beerling  55:04

Sure. I mean, if I remember correctly, I suspect that’s due to transportation distances. So for large countries, the kind of dominant component of cost is transport. But if we were to kind of dig down to a specialist study for Canada, I was nervous that you could probably access alternative rock sources that are closer you could access for us tonight mines. And you could probably think, as I said earlier, a bit more creatively about how you brought in basalt from the northern states that are just being produced, and bring it across the border. That kind of level of regional detail within a nation was sort of beyond our initial study. But I could see that there would certainly be ways to bring costs down in Canada, if we got if we got creative and started focusing, you know, on Canada in a lot more detail.

Metta Spencer  55:57

Thank you. Yes, I was just wondering how close are you to feeling confident enough? Both that the quality of the soil will be improved in that will matter in monetary terms that you that the farmer will actually benefit from applying this soil amendment? And how much are how confident are you that the amount of carbon sequestration that this procedure does will be enough to make it worthwhile or highly desirable for the government? Now, if we were to start a campaign this year to try to convince a Canadian government to get the Ministry of Agriculture onboard and incentivize even paid farmers to do this, so get going with it? Are you sure enough that we are not going to wind up with egg on our face?

David Beerling  57:01

What we found in our trials is, after you know, four or five years, actually seven, we’ve got seven years of data, definitely improved soil health. So one of the things that happens in in intensive agriculture in the US and elsewhere is when you grow the crops, you know, the harvest the biomass, oftentimes, it’s taken off site. So you’re gradually depleting your soils of trace elements that are important for crop health. But you’re in every time you every time you have a harvest and you take it off site, you’re basically depleting those plants, this plant available soil pools. And as the basil breaks down, what it does is releases those trace elements like molybdenum, potassium, that are important for crop health, and replenishes those stores in the soil. Additional one that it releases is silica, which is very important for most of the major food crops and grasses. They need it to build healthy stems make them resilient to stress. And again, as you harvest your biomass, you gradually deplete your soil pools of silica. Now as basalt, whether it weathers it adds silica back into the soil. But the farmers make it worse because they actually add lime. And as you add lime and increased soil pH, it makes the silica unavailable to the plants. And what we’ve shown is that actually, the additional silica from the basalt compensates for that increase in pH. So it could prove to be crucially important in helping the silica status bar soars, which is vital for healthy healthy crops. So yeah, so I think, you know, a bit of a rambling answer, but the bottom line is, I’m feeling fairly confident after seeing six or seven years worth of data that this is good news for soils.

Metta Spencer  58:52

Wonderful. Thank you. Okay, no,

Noah Planavsky  58:55

yeah, so the the other key aspect, obviously, as we travel right needs to needs to actually work for, for the farmers for the key stakeholder that this affects most and, and if you’re going to, if you’re going to try to get governments or companies to invest in this, you need confidence that it also is removing carbon, there are a wide range of their wide range of ways in which people are trying to do this, right now track the actual extent of carbon dioxide removal that hasn’t worked, or the extent of carbon dioxide removal that’s occurred. And I would say that we should be suspicious of these some of these methods, I think are not going to work at scale. Some of these methods aren’t providing enough attention to some details that matter.

Metta Spencer  59:39

When you see some of these methods, you mean so certain applications of the of the rock test or you

Noah Planavsky  59:46

know, ways of tracking ways of actually trying to quantify the amount of carbon dioxide removal that has occurred. But the takeaway from that so that was a cautionary statement that this is something where We should be careful and we shouldn’t exceed except that basically it’s very rare that anybody can do this. But if there are methods in place that make sense that are grounded in basic mass balance that allow you to actually track how much carbon dioxide removal that’s, that’s been occurring. And so I think the, the short answer from that is having similar to David’s having ups and downs and obviously fits and starts and how we do this years later and thinking about this have pretty high confidence that this is something where, right it makes sense in many soils, and we can track what is actually happening in a way that makes sense. And you can present clear evidence of how much carbon dioxide removal is actually occurring.

Metta Spencer  1:00:52

That degree. All right, we’re going to come after you. We’ll have you on a speaking tour. With banners and placards and everybody a marching band and everybody saying go with this, we’re going to do it. Do you think so? Ellen?

Ellen Judd  1:01:09

Yes, I think it’s wonderfully energizing. And it’s inspiring to see how people are finding solutions to problems

David Beerling  1:01:18

cannot you just I don’t know if we’re out of time, I can just offer you one additional thing about candidate being being done at the moment she’s worked on by Shannon Sterling at Dalhousie, and they’ve realized that actually, rather than treating your acidified forests, with lime, you could actually do it with crushed basalt. And this would help reverse the acidification on the soils, but also capture carbon. At the same time as the basalt dissolves and releases its nutrients, like its phosphorus and potassium, it can help the trees grow better and restore the degraded soil. And I think Shannon’s got funding now from the Canadian government to carry out small counts, small scale trials to investigate how this might work. So it’s a really exciting new application for enhanced weathering that’s directly relevant to Canada that we just haven’t touched on yet.

Noah Planavsky  1:02:09

Yeah, so it’s also one of the things from restoration from historical damage from coal mining has led to ecosystem degradation in a way that we can reverse that while driving carbon dioxide removal.

Ellen Judd  1:02:22

That’d be wonderful. Maybe we can get this person on the show.

David Beerling  1:02:26

She’d be great. I’m sure.

Metta Spencer  1:02:28

That’s wonderful. Well, this has been extremely helpful. So we will have at least two more shows maybe three more shows on this topic. And so we’ll be back in touch with you for sure. You’re the pioneers. And I appreciate it. Very much. Okay, thanks.

David Beerling  1:02:47

Thanks. Great to meet you. 


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