Can we use natural processes to suck CO2 back out of the atmosphere? It sounds tempting because the risks of unintended consequences with processes that have been taking place already on the planet for millennia are significantly lower.
One such process is weathering, and a company looking to do Enhanced Weathering thereby sucking millions, and hopefully billions of tons of CO2 out of the atmosphere (while simultaneously improving agricultural land) is UNDO.
I invited UNDO's Head of Research Mel Murphy and UNDO's Head of Carbon Simon Manley to come on the podcast to tell me all about it.
We had an excellent discussion talking about how Enhanced Weathering works, how it can be monetised, and how UNDO's ambition is to be the first company in the world to remove 1 billion tons of CO2 from the atmosphere.
This was a truly fascinating episode of the podcast and I learned loads as always, and I hope you do too.
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Enhanced weathering by 2050 can account for up to 45% of the United Kingdom's, emissions targets towards achieving net zero. And they've provided an estimate that enhanced weathering by that time period can sequester, I think the estimate was up to 6 million tons of CO2 per year, just in the UK alone. And so there's a considerable potential for enhanced weathering to sequester mega tons of CO2 per yearTom Raftery:
Good morning, good afternoon, or good evening, wherever you are in the world. This is the climate 21 podcast. The number one podcast, showcasing best practices in climate emission reductions. And I'm your host, Tom Raftery. Don't forget to click follow on this podcast in your podcast app of choice, to be sure you don't miss any episodes. Hi everyone. Welcome to the Climate 21 Podcast. My name is Tom Raftery, and with me on the show today, I have my two special guests, Mel and Simon. Mel and Simon. Welcome to the podcast. Would you like to introduce yourselves?Mel Murphy:
Hi, my name's Mel Murphy. I'm the head of research at UNDO. I've got over a decade of experience as the Geo Chemist, and my research is focused on the natural weathering cycle. And at UNDO, I'm switching gears to enhanced weathering, where we're setting up some exciting field trials and we're developing tools and technologies to basically quantify the weathering process in nature.Simon Manley:
And I'm Simon Manley. I'm the head of carbon for UNDO. I'm a carbon removals and voluntary carbon market specialist. And, my role in the role of my team here at UNDO is to make sure that our physical project activities transition into high integrity, high value, high quality carbon credits.Tom Raftery:
Very good, very good for people who might be unaware and let's be honest. In this case, that's largely me. I know a little bit about what enhanced weathering is, but not a whole lot. So for people who might not know what Enhanced Weathering is, can we have a quick enhanced Weathering 1 0 1?Mel Murphy:
Sure. Yeah. So natural rock weathering is a geological process that takes carbon dioxide from the atmosphere. And this has been operating over, hundreds of thousands of years. And so naturally this weathering process locks away billions of tons of CO2 over geological time scales. And so enhanced weathering is simply speeding up this process. And how this process works is carbon oxide dissolves into rain water, and this forms a dilute acid, which reacts with the, rocks and in, in the case of us at Undo, we're working with basalt. And so as this basalt gradually breaks down, it releases macronutrients and micronutrients including bicarbonate, which is another form of carbon. And so this bicarbonate moves through the ecosystem where it ultimately ends up as the ocean permanently removing CO2 as a solid carbonate mineral. And I always like to say that you can imagine this is precipitating, lobster shells on the bottom of the ocean. And so this process of enhanced weather we're spreading, crushed up, basalt rock onto agricultural land or urban soils, where this, this weathering process is further enhanced by the role of plants and microbes and speeding up this weathering process to removing, removing carbon dioxide from the atmosphere.Tom Raftery:
Okay? And so the crushed basalt is spread on agricultural land. Rain water falls on it. What happens next?Mel Murphy:
So as the rock breaks down, it releases cations positively charged ions such as calcium, magnesium, and this CO2 in the atmosphere forms carbonic acid, which when it dissolves the rock forms a molecule called bicarbonate. And so this is one of the forms of removal of CO2 is as this aqueous form of bicarbonate, and then that moves through the, the earth system and ultimately is precipitated in the ocean.Tom Raftery:
Okay. And how are we quantifying the amount of CO2 that's captured using this method?Mel Murphy:
So we're using a few different tools to do this. We have a one dimensional reactive transport model, a geochemical model where we input the climate parameters of the region we're working in. We take very accurate knowledge of the mineralogy, of the rock, the reactive surface area, and how much rock we're adding in tons per hectare. And we couple this to the physical parameters and, and the chemical parameters of the soils in which we're adding it to. And then we add in, of course, CO2 from the atmosphere. We also include how much CO2 is produced from biology in the soil profile, from root exudates, and microbial respiration. So our geochemical model incorporates all of these processes so that we can simulate how much carbon we hope to predict. So this is coupled to a physical measurement technique where we are using field trials and we are looking at the generation of this bicarbonate or alkalinity as it's called in the soil poor waters. Mm-hmm. . We're also looking at other weathering proxies such as calcium and magnesium. And we're looking at the evolution of pH because one of the interesting co-benefits of this application of basalt to soils is that actually can increase soil pH. And so this is one of the signals that we're looking at in the field.Tom Raftery:
Okay. Just on that, I mean, I, I can imagine that soil pH affects the crops or the, biome in which the, soil exists. and I assume there's a, there's a, there's a threshold beyond which it goes, where it starts to become detrimental. So is, is there kind of a narrow band of pH that you're operating within in the soil?Mel Murphy:
There is, I'd say for most farmers the application of lime is a routine practice and it's quite desirable in many agricultural settings to increase soil pH. And so we don't say at this stage that application of basalt can directly replace lime. It certainly does have co-benefits and can improve, soil health and crop yield. And we do see an observed increase in soil pH, but it isn't as dramatic of an increase as you would see from liming procedures. And so because of the time scales that we're operating on, the dissolution of these minerals in the basalt, it takes a bit longer than, that of lime. And so we're looking at applications reapplications of this basalt every say, three years at this stage. And this is such that the pH evolution can increase and start to tail off, and then you would reapply. And so we are looking at this sort of frequency in order to manage the pH evolution. But another consideration is if you go too, like too far into the high pH range mm-hmm. you can actually precipitate pedogenic carbonate. And this is something, this is also a, a storage of atmospheric co2, but it's not as efficient as if the carbonates are precipitated in the ocean. And so when you're in these really high pH, very alkaline soils, you have a tendency, more of a tendency to precipitate these carbonates and so there is some sort of optimization of what pH range you'd want to be operating in.Tom Raftery:
Yeah, sure. I can imagine. How much CO2 are we talking about sequestering using enhanced weathering? You're saying you're doing it, you're measuring it per hectare of land, so how many hectares, how much co2?Mel Murphy:
I think the way we're looking at it is a a given basalt contains fast weathering minerals, slow weathering minerals, and each of these minerals have a different capacity to sequester carbon. And this is primarily based on how much calcium and magnesium, these minerals contain, which can then be coupled with the atmospheric co2. And so what we're seeing for most of the basalts that we are looking at, we see that if we spread about four tons of rock, we sequester about one ton of co2, and so we're working on this four to one ratio. And this is because calcium and magnesium is hosted in other minerals, not just these fast weathering minerals, but they can also be hosted in slow weathering minerals or secondary minerals, such as clays. And so we're using a much more conservative estimate than has been published in some of the academic literature.Tom Raftery:
Okay. And does it depend on soil type? Does it depend on ambient weather? I mean, I'm based here in the south of Spain and we had a small bit of rain in the last couple of days, and it's the first rain we've had since April I wanna think, and it was only a light shower, so I can't imagine it working too well here, for example.Mel Murphy:
So, the weathering is accelerated under warmer temperatures and under high rainfall conditions. However, my research, prior to joining Undo has been looking at weathering in the Arctic, and it's quite remarkable that we actually see considerable weathering in Greenland, in Siberia, and this is because of physical erosion, not this chemical dissolution that we are talking about now. And when you've got high reactive surface areas, such as we do in enhanced weathering, you have more surface for these weathering reactions to take place. Mm-hmm. . And in most agricultural settings, even if we do have quite arid conditions, they would be irrigated. And so it's the addition of this irrigation water that can also promote weathering. Okay.Tom Raftery:
Okay. And so this sequestering of carbon, I had a, an episode, a couple of episodes back where I was talking to, a company called Patch and Patch are a company who have a platform for trading carbon credits. And, they talk about different, types of carbon credits, some sequestered carbon for maybe a hundred years, some for maybe 10,000 years, and there's a whole spectrum there. In terms of the carbon being sequestered using enhanced weathering, is it 10 years? Is it 10 million years? Or where does it fall?Mel Murphy:
So in the case of the generation of bicarbonate, this dissolved aqueous form of carbon dioxide. This has a residence time in soil poor waters from days to, hundreds of thousands of years in soils, and it depends on the hydrology of the local system, but in the ocean, the residence time of bicarbonate is of the order of about 10,000 years, and then the precipitation of carbonate is effectively locked up for geologic time scales. So we consider. the permanence of removal of the order of, thousands to hundreds of thousands of years for enhanced weathering.Tom Raftery:
Okay, nice. And roughly how much CO2 are we talking about? I know you said four tons basalt to one ton co2, but obviously just taking one ton, the CO2 out of the atmosphere isn't going to achieve a lot. I mean, it doesn't hurt, but, we need to be getting out tens of billions of tons per year. So where do you see enhanced weathering contributing to that?Mel Murphy:
There's a recent study that just come out in Nature that suggests that, enhanced weathering by 2050 can account for up to 45% of the United Kingdom's, emissions targets towards achieving net zero. And they've provided an estimate of a, that enhanced weathering by that time period can sequester a, I think the estimate was up to 6 million tons of CO2 per year, just in the UK alone. And so there's a considerable potential for enhanced weathering to sequester mega tons of CO2 per year.Tom Raftery:
Oh wow. So just 60 million tons a year just in the uk. Which, which comes to about, you said 45% of the UK's emissions.Mel Murphy:
So I think I've just pulled up the estimate here. So they're, they're estimating, six to 30 mega tons of CO2 per year by 2050 just in the UK alone. So this is accounting for up to 45% of the removals required to meet the UK's net zero emission. Wow,Tom Raftery:
that's impressive.Simon Manley:
The, um, the total available market for, enhanced weathering globally. It's important to stress the rock that we use for this activity is sourced as a byproduct, principally from the aggregate sector. Globally the aggregate sector produces 600 million tons of rock, that is of the correct particle size and the correct mineralogy to deliver enhanced weathering. Using the ratios that we just talked about that has, that's basically a, an unexploited carbon asset with the potential of delivering 150 million tons of carbon removal, over its lifetime. And that resource is available every year. Fantastic.Tom Raftery:
Fantastic. That's amazing. we know that when we start interfering with nature, there can be unintended consequences. Are there any, I know it's hard to say, but are there any potential unintended consequences to suddenly spreading, tens of millions of tons of basalt on agricultural land globally?Mel Murphy:
We're partnering with farmers and we are very, it's very important to us that we don't do any harm to their soils or to their crops. And so from our operations, we've learned that we, we are spreading 20 tons per hectare. Um, that's our commercial application density. Mm-hmm. . And in that, in some of the academic papers, they're suggesting that you could apply up to a hundred, tons per hectare on an annual application. We're seeing that even if you're putting 40 tons per hectare, you're starting to get significant compression of the soils and this is not a good thing. So we we're operationally, applying a much more conservative limit. The other thing that we're really, cautious about is heavy metals. And so some silicate rocks have, elevated heavy metals, and in particular, chromium and nickel are the ones that can be accumulated in, in mafic rocks, such as the ones that are being used for enhanced weathering. So we have a very rigorous heavy metal screening protocol. All of our rocks are screened for all of the potentially toxic heavy metals, and we use European guideline values. and we are comparing our rock to soil guideline values before we do any spreading activities.Tom Raftery:
Okay, Fantastic. Now, I, I mentioned, I, talked to Patch, and there are other platforms as well for selling carbon credits. Where are you guys on that? Have you started doing this? Are you still at trial stage? You know, where, where are you on that kind of scale of maturity?Simon Manley:
Well, our ability to generate carbon credits depends entirely on, having an accredited quantification approach, which is, uh, not just of our own creation, but something that's been approved by the, voluntary carbon market standards. Right now as we speak, there is no methodology out there for the quantification and monitoring and reporting of, of enhanced weathering. So we have developed one, we've written one, and we've done so in strict adherence to, the principal guidelines on this subject, which are provided by ISO ISO 1 4 0 6 4 part two. Which are the guidelines which underpin all of the major voluntary carbon market standards. So, that is now drafted and it is out for validation by an accredited independent validation body. We're expecting that to be in place within six to eight weeks from now. At that stage we will have a validated methodology and then we'll begin to then verify projects, uh, which are being implemented now in order to generate, our own, uh, ex antit and then, uh, ex post, or in other words, verified carbon credits. but we won't stop there. We appreciate that we need to get this methodology into the public domain. So, soon after the ISO validation we'll be, looking to get this methodology approved onto the per trading platform. And we're working closely with them at the moment in order to make sure that, their enhanced weather methodology, uh, is, you know, compliant with ours. And then after that we'll be looking to get it into an crow back standard. So one of the big four from the voluntary carbon market gold standard there, acr. Um, we'll probably end up working with one of those. So, and, and that, I'm talking about between the next sort of 12 to 18 months, we'll have, that full process complete.Tom Raftery:
Okay. Okay. And how are you sourcing funding between now and then?Simon Manley:
Well, we are generating some carbon credit revenue now. There are customers and companies out there who are prepared to accept the level of rigor and robustness that we're applying to our sort of science. and also the methodology in it, in its current form. It's a relatively limited market, and in that, It will expand significantly, as we go through that process that I've been just been talking about. So ISO p and then a crow backed, and so there is some carbon credit revenue coming into the business now. Also supplemented by the fact that we are investor funded, so that's how we're funded the business currently.Tom Raftery:
Okay. Okay. Interesting. Enhanced weathering. I mean, I've published so far around 87 episodes of this podcast, and this is the first time I've had a, a podcast episode dedicated to enhanced weathering. I think it was mentioned on one previous episode as kind of a, by the way, I think it was the, the episode where Peter Fiekowski. Why is that? Why have, why isn't enhanced weathering talked about more? If it can, grab as much carbon outta the atmosphere as we're talking about now?. I,Simon Manley:
I think carbon removal as a, concept has only really been in the public consciousness. and actually, I mean, I think that's a generous description put by saying public. I mean, it's only been into consciousness of the voluntary carbon market community, for a few years. The whole idea that we need to remove carbon from the atmosphere rather than avoid the future production of it. And there are only a handful of technologies and techniques which are sort of acknowledged to, to achieve that. So that's one thing, but on the flip side of that, you've got, you know, weathering has been taking place for, for millennia. And correct me if I'm wrong here, it's something like a hundred 80 million tons of CO2 is removed from the, atmosphere every year through the natural weathering process.Mel Murphy:
So just to limit, so I think we're sequestering about a gigaton a year from silicate weathering, but basalts alone account for about a third of that.Simon Manley:
Okay, so, it's been happening for a long time, so you could describe it as the, the oldest carbon removal technology that no one's ever heard of. . Tom Raftery: Okay. Okay. Very good. And, what is Undos business model? Is it just selling carbon credits and, you know, using the income from that to, pour more basalt on agricultural land? Well, we're in, we're in scale up phase at the moment but yes, in a nutshell that is correct. Our business model is essentially around, implementing projects, certifying and verifying to the highest possible standards, and then selling, those carbon credits into the voluntary carbon market. We sell our principle market for carbon credit sales to be around sort of the net zero community. As you know, carbon removal's, constitute, an essential part of, the net zero journey once all residuals have been once all companies are decarbonized to the point where they have the minimal amount of residuals, then those need to be addressed with carbon removal credits. So it's that market that we're going after, and that's gonna be our principle source of revenue generation.Mel Murphy:
Okay. I would say though that the company motivation is really that we are living through a climate emergency and we really desperately need to sequester carbon at scale in order to maintain global temperatures at less than 1.5 degrees above anthropogenic levels. And I think that that mission really comes through with all of the, staff that work at Undo. This is something that we're all very passionate about and I think that that's really important to remember that this is the main driver towards scaling up this technology. It is really to sequester carbon at scale.Tom Raftery:
Yeah. No, absolutely indeed. And and I, that's why I was mentioning earlier the, the tens of billions of tons that we need to get outta the atmosphere every year. It's, it's just, it's a entire emergency. It really, really is. So, I'm, I'm delighted to hear that this is a scalable technology. On the other side so you, you, you talked about the, carbon credit side, but the other side of it is the, the farmers or the people with agricultural land, are you selling basalt to them? Are you paying them to spread it? How does that work?Simon Manley:
So, so we have a value chain for the implementation of the projects, which starts with sourcing the rock, then the transport with that rock to the application site. And those application sites tend to be, degraded agricultural land owned by land owners. That model is evolving at the moment. At the moment, we, do not require the farmers to pay for at all. The upside to them is either in the form of carbon, if, if that is, or of interest. In other words, there's a sort of carbon, proposition, that they could utilize in terms of either their own carbon reporting or carbon inventory, or they could take a share of the carbon, uh, revenue that comes as a result of us selling the credits.Tom Raftery:
Ok. Interesting. So I'm sure that the monitoring and the reporting of this is going to prove challenging. How are you approaching that?Mel Murphy:
It is very challenging. It's very difficult to measure a weathering signal in the field, and we're not the only, group to find it challenging. So we're approaching this from, two different methods. We're designing field trials where we're doing high resolution, high density sampling. So we have, regions which are typical of the regions in which we're operating. So we have one, um, established in Scotland at the moment. We're establishing more in the Pacific North west in, in the usa and what we're doing is we're doing a gradient basalt edition trial in the field. We've got sensors that are installed at different depths and that gives us depth and time integrated readings of parameters such as soil temperature and moisture content. But we're also measuring pH and electrical conductivity, which are direct, um, measures of weathering. So this is being coupled to. Taking soil poor water samples, and we're measuring for things like soil, pH alkalinity, major cations, and anions. And this allows us to quantify how much carbon is being sequestered. We're also looking at the physical soils themselves and looking at things like the exchangeable cations and the presence of any pedogenic or soil in organic carbon in the soils. We're coupling this to a Meza Cosm study approach, and so a soil meza cosm, if you visualize, you have a a tube and you insert it into the soil and you pull it up. This is sort of the transition between a pure lab study and a pure field study. Mm-hmm. , it enables us to replicate the climate conditions that we're operating in through irrigation with a pump. And we're simulating the weathering by adding the basalt to the top. And in this semi constrained system, what we put in at the top, it can either evaporate a little bit at the top, but predominantly what we're adding comes out the bottom. And so this enables us to capture that effluent and measure the same parameters that we're measuring in the field. And so in combination, the field studies and the soil mesocosms will allow us to better calibrate our one dimensional reactive transport weathering model. And so what we're hoping to do is better understand the weathering in different regimes in which we're operating different climates, different soils, different basalts, so that we have better confidence in in our weathering models.Tom Raftery:
Okay. Very good. Very good. So you've chosen basalt as your. Platform, I guess, or your medium for, uh, your enhanced weathering. Are there other types of enhanced weathering that are out there? Why, why basalt as opposed to any others if there are others?Mel Murphy:
So one of the other minerals that is being used for enhanced weathering is ULA night. So this is a calcium silicate mineral. Um, it's not very abundant and so this is arguably probably the best mineral that can be used cause it has very low heavy metals. But another mineral that is quite commonly being used is olavine. So olavine is one of the fastest weathering pure minerals that has capacity to sequester carbon, carbon dioxide. However, this particular mineral, again, is not as abundant as basalt, but also has a tendency to have higher heavy metals in it. Mm-hmm. . And so we're, we're choosing to use basalt in our operations at Undo because it's highly available. It has much lower, heavy metal limits, and yeah, it has a great potential to sequester carbon dioxide.Simon Manley:
I think it's important to focus that the, properties of basalt allow us to deliver those co-benefits to farmers in terms of its ability to improve, uh, soil health and nutrient uptake and nutrient cycling and the co benefits associated with carbon oxide removal is, is a sort of crucial characteristic of the projects that we're implementing.Tom Raftery:
Nice, nice, nice. So where to next for undo? I mean, you're at very early stage, you said you're scaling up. You're hoping to be selling carbon credits on the accredited carbon markets in the next year. I, I wanna say, what's your like, five year plan? Where do you wanna see yourselves?Simon Manley:
Well, we have an ambition to be the first company in the world to remove a billion tons of carbon dioxide from the atmosphere. We're gonna start with a million, but we're gonna scale up from there. So, within five years we hope to, well on that journey, if not having achieved it. And the way that we're obviously gonna do that is through, significant scale up of our operations, in global locations. In global markets.Tom Raftery:
And what are the challenges to achieving that goal?Simon Manley:
Well, one of the advantages of enhanced weathering, unlike some other carbon removal technologies, is that relatively low barriers to implementation. You don't need to use technology that perhaps hasn't been invented yet. You aren't looking at high CapEx in order to get projects implemented. It's all about operational scale up, operational capabilities and capacity, and obviously having the skills to convert physical activities into carbon credits that you can sell to generate revenue. And we've got all of those pieces of the jigsaw in place. So, the challenges will be, operation and capacity building, and so, just proving the value chain works, and then scaling those global markets. Okay.Tom Raftery:
Super, super. We're coming to the end of the podcast now. Is there any question that I have not asked that you wish I did or any aspect of this we haven't touched on that you think it's important for our people to be aware of?Mel Murphy:
I'd like to say there's a few unknowns around the science. And so something that we're looking to do at Undo is we're really keen to continue to develop the research that's taking place on enhanced weathering. So there are, anecdotal benefits and some, inicio studies that suggest that enhanced weathering can suppress nitrogen dioxide or NOx emissions. And so something that we're really interested in doing is looking at the role of this, spreading of basalt rock and how can it help with farmers to reduce their emissions, of other greenhouse gases. And I think we're really keen to develop, um, where we are in the process of developing field trials in collaboration with farmers. And also the Newcastle University Research Farms to look at the agronomic co benefits to soil health and, to plant, um, and crop yield. And so this is, I think, something that, is really exciting and has great potential.Tom Raftery:
Okay. Super. Super. If people want to know more about yourself, Mel Murphy or Simon Manley, or Undo, or any of the things we discussed on the podcast today, where would you have me direct?Mel Murphy:
So I would send you to our website, so un dash or hyphen do.com. We can pop that in the notes.Tom Raftery:
Lovely, lovely. I'll absolutely, I'll absolutely put that in the notes. Great folks, that's been really, really interesting. Thanks a million for coming on the podcast today.Simon Manley:
Not at all. Absolute pleasure.Mel Murphy:
Thanks for having us.Tom Raftery:
Okay, we've come to the end of the show. Thanks everyone for listening. If you'd like to know more about Climate 21, feel free to drop me an email to Tom Raftery at outlook.com, or connect with me on LinkedIn or Twitter. If you like the show, please, don't forget to click follow on it in your podcast application of choice to get new episodes as soon as they're published. Also, please don't forget to rate and review the podcast. It really does help new people to find the show Thanks. Catch you all next time.