Catalyst with Shayle Kann - How well does soil actually store carbon?

Episode Date: October 6, 2022

Don’t miss our live episode of Climavores in New York City on October 20! Sign up here for a night of live audio and networking with top voices in climate journalism.  There’s a buzz right now about paying farmers to trap and store emissions. Soil is a carbon sink, and certain farming practices accelerate carbon capture while others hurt it.  Enter soil carbon credits to incentivize sequestration through methods like cover cropping, no-till farming and agroforestry. These are practices often included under the umbrella of regenerative agriculture. So what does science say about how well these methods actually lock away carbon? In this episode, Shayle talks to Eric Slessarev, staff scientist at Lawrence Livermore National Laboratory where he studies soil carbon.  Eric says there’s a lot we don’t know about how well these practices actually work. There are even more fundamental questions like how much carbon is in the soil. Turns out dirt is pretty complicated. They cover things like: How exactly carbon gets into the soil and why it sticks around. The challenges with measuring soil carbon. The difference between soil carbon and enhanced weathering. How microbes, minerals and the depth of root systems affect storage. Specific practices like no-till farming, agroforestry and cover cropping. Why our soil carbon models may need a big update. Resources: Canary Media: Carbon storage gets dirty: The movement to sequester CO2 in soils International Soil Carbon Network Seminar Series: Towards a Durable Understanding of Soil Carbon as a Tool for Climate Adaptation and Mitigation Catalyst is a co-production of Post Script Media and Canary Media. Catalyst is supported by Scale Microgrid Solutions, your comprehensive source for all distributed energy financing. Distributed generation can be complex. Scale makes financing it easy. Visit scalecapitalsolutions.com to learn more. Catalyst is supported by CohnReznick, your comprehensive source for navigating the complex and evolving financial, tax and regulatory landscape of the renewable sector. Visit cohnreznick.com to learn more.

from the studios of PostScript Media and Canary Media. I'm Shale Khan, and this is Catalyst. The central thing to keep in mind is that microbes like to break down organic matter. It's how they make a living. And so any one of these practices might succeed in building up some carbon, but the amount of time it sticks around is unclear. So many years ago, when I first got into the energy sector, I felt like the more I learned, the less I knew.

It took me a really long time to start turning in the opposite direction, where the more I learned, the more I knew. I'm back at that early point when it comes to soil carbon. The more I learn, the less I feel like I really understand about it. Nonetheless, I find it fascinating. I hope you will too. This week, digging in on the science of soil carbon. When utilities need flexible capacity they can count on,

they turn to Energy Hub. Energy Hub works with more than 170 utilities, coordinating over 2.5 million devices to manage 3.4 gigawatts of flexibility built for the moments when utilities can't afford uncertainty. Energy Hub builds and operates virtual power plants that utilities actually stake their grid planning on, coordinating EVs, batteries, thermostats, and more through a single platform built for utility scale. Predictive, verifiable, and designed to perform when it counts. Learn more at energy hub.com. Trillions of dollars are flowing into clean and critical infrastructure, but those investments aren't driven by technology alone. They're shaped by markets, by policy, by capital, and by the institutions that connect them. I'm Alfred Johnson, CEO of Crux, and host of a brand new podcast, Critical Capital. Each episode, I talk with people deploying capital, shaping policy and building the clean economy. Tune in as we unpack how progress is actually made. Listen to Critical Capital on Spotify, Apple, or wherever you get

your podcasts. I'm Shail Khan. I'm a partner at the venture capital firm, energy impact partners. Welcome. So regular listeners will remember that a couple months ago, I had a conversation with Freya Che from Carbon Plan all about soil carbon credits and soil carbon markets. I've been interested in this topic for over a decade because soil contains both maximum promise and, in my opinion, maximum peril as a so-called nature-based solution to

climate change mitigation. It's also just a really important carbon sink as part of the natural carbon cycle. But I realized after having that conversation that we were maybe putting the cart before the horse, or I guess the plant before the seed. Anyway, it sort of makes no sense to talk about soil carbon markets without first talking about soil carbon itself. What exactly is soil's role in the carbon cycle? What do we and don't we know about the impacts of changing agricultural practices and other hacks

to impact soil carbon sequestration? What are those hacks that might help us engineer soil to capture and store more CO2? And then once we understand what we know about all of that, then we can think about how and whether we should create a virtual commodity market to compensate growers and landowners for taking actions that benefit the planet. So here's that first conversation coming second. If you haven't listened to the episode with Freya, I highly recommend going back after this one. And if you have, then consider this one the prequel.

Our guest to talk about soil carbon science is Eric Slesserov, who has collaborated on a report on soil carbon with carbon plan, where Freya works, and in his day job as a staff scientist at Lawrence Livermore National Lab, where he studies, of course, soil carbon. Here's Eric. Eric, welcome to Catalyst. Well, hello, thanks for inviting me. Thank you for being here. I'm excited to talk to you about soil carbon and dig in.

I'm going to say that once and then I'm going to never say it again. All right, so let's talk about soil carbon at the highest level. My framework for thinking about this stuff is basically there was a natural soil carbon cycle predated humans or predated human agriculture. Then we've spent the past few thousand years messing with it by doing agriculture and by doing a bunch of other things. And then now we're interested in perhaps trying to mess with it again, only this time to try to maximize the amount of carbon that soil takes up and keep it in there as long as possible for the purpose of mitigating climate change. So before we talk about the things we might want to do to mess with it now, how did we mess with it when we started agriculture? The answer to that is complicated, but I think there are a couple main ways that agriculture has altered soil and its role in the carbon cycle. So plants are fixing carbon and they're adding into the soil through a number of ways.

See, their leaves, and to a large extent, via their roots, and also through carbon compounds that leak out of the roots or exuded from the roots. We call them exudates. And so they're adding carbon to the soil, and that carbon builds up because microbes can consume it. They can eat it, but they can't keep up with the rate at which plants are adding that. carbon under all circumstances for a number of reasons. And so the sort of natural baseline condition is that there's an ecosystem on the surface. There are plants. They're fixing carbon.

They're introducing it. There are microbes that are constantly breaking it down and releasing it back to the atmosphere. But those two processes ultimately come into some kind of balance that allows carbon to build up to a certain level in the soil. And how much builds up depends on a whole bunch of factors. But at some level, it depends on how much. plant growth is happening in a given place. So when humans come along and start developing agriculture, they're really finding another use for that plant growth at some level.

And so agriculture involves harvesting biomass, replacing forests with cropland potentially, converting ecosystems that were composed of deeply rooted plants like perennial grasses with ecosystems that are managed by humans and composed of our crop plants, which tend to be fairly short-lived and hence shallow-rooted and therefore add less carbon to the soil, particularly at depth. And so we're managing the plant communities in agro-ecosystems when we practice agriculture, and therefore controlling the amount of carbon that actually makes it into the soil, and at some level choking it off. And so what that means is that the balance between plant inputs

and the constant chewing away of those microbes on the carbon shifts, and we end up with less carbon on balance in those agricultural soils. So that's one half of the answer. But the other half is that agriculture often or almost always involves disturbing the soil. originally by hand or plowing a field with oxen or whatever livestock you've got available, and nowadays using machinery. And that disturbance, and also the amount of time the soil spends bare without vegetation on it, increases the rate at which soil is eroded.

And we think humans have increased the rate of soil erosion massively in agricultural lands since the advent of agriculture. And that means the carbon in that soil leaves the system, although it doesn't necessarily get reamitted to the atmosphere the way it does if microbes eat it and then respire it, it ends up in water bodies, essentially, in rivers and lakes or at the bottom of the ocean. Okay, so maybe I can try to summarize what you're saying,

and then we could dig into it further. I have already said dig into it a second time. This is going to be really difficult for me. inevitable. Yeah, you're just going to have to get used to. It happens to me, too. It's a big problem. Okay, so you're saying first half of the answer is by discovering agriculture and then pursuing it all over the world, we've basically limited or maybe reduce the total amount of carbon that is sequestered in the soil. And then second, in addition to that, we've, we mess with the soil. And in messing with the soil, we extract the carbon, though it's maybe sometimes goes into the, the atmosphere sometimes doesn't goes to places like the oceans. And that sort of last piece of like when it sometimes goes some places and other places gets to this broad thing that I always face whenever I'm having conversations about soil carbon, which is, it seems like there's still just an enormous amount of uncertainty that we have and a lot of locational specificity. Like,

it's hard to make these broad brush comments about what impacts a given thing we'll have on on soil carbon sequestration or release or where it will end up. Is that right? Like, where do you feel like we are in our scientific understanding of soil carbon and how that should relate to how we think about all these practices that we'll talk about in a minute that are aimed at trying to increase soil's role as a carbon sink? Yeah, you know, I think broadly speaking, that sounds right to me. there is still a huge amount of uncertainty and place specificity.

It's not that we know nothing. We know a good deal. And soil scientists and biogeochemists and the whole pot of people that study soil that label themselves in various different ways, I've been working very hard to understand the complexity, but the reality is there's still a huge amount of uncertainty. For instance, that erosion question I just brought up earlier, there's been an ongoing debate about whether erosion of soil and transport of that carbon

amounts to a source or a sink of CO2 to the atmosphere. We don't really even feel certain about the sign of the signal there. And that debate's resolving to some extent, but we know it's probably not a very big source or a very big sink. So gradually we're working our way towards higher certainty. But it's very hard to actually predict what's going to happen in any particular location, even with our best sort of current models. And I would also say that our, you know, even setting aside prediction, our conceptual understanding of what goes on in soil and why carbon sticks around as long as it does in soil has been evolving. really rapidly over the last couple decades.

And it's by no means settled. So that doesn't mean that we're totally confused and you shouldn't listen to the scientists, but it also means that this is not, this is not Newtonian mechanics, right? We can't calculate anything with high precision. We're still figuring out the basics of how things work at some level.

So I want to talk about some of the things that are rising in prominence now as actions that we might be able to take to use soil as a greater carbon sink and draw down CO2 from the atmosphere in some cases and get your perspective on where they fit in the mix, how much certainty we have around them, where the big questions lie and so on. There's now a bunch of conversation around enhanced weathering, which is sort of independent from soil carbon itself. We're not really trying to create new soil when we are doing enhanced weathering, right? Yeah, I mean, enhanced weathering.

that's a whole other can of worms at some level. I mean, is that also a soil pun? Maybe. So, and what I've talked about so far is organic carbon in soil, but soil has this huge role in the inorganic half of the carbon cycle as well, regardless of whether that inorganic carbon is stored in the soil or not. And that's because the weathering reactions that happen in soil, and these are basically transformations of minerals that formed at high temperatures and pressures deep below the earth's surface,

which are not thermodynamically stable in soil or in ecosystems at the earth surface. And as they're transformed, the reactions basically consume acidity and release divvalent and monovalent cat ions, so like calcium, magnesium, sodium, for instance. And that reaction on balance ends up basically pulling CO2 out of the atmosphere. And that CO2 then ends up as bicarbonate in water in the soil. It could end up in a stream and then flushed out to the ocean, where it's essentially sequestered in the ocean, or it could end up staying in the soil as a carbonate mineral, right?

So that process is going on all the time, and it's hugely important in regulating Earth's climate at really long timescales and might be influenced by things like mountain building, for instance, like tectonic processes, right? So it's slow, though. It's a very small fraction of the instantaneous carbon balance of the Earth at any given moment. The biological half of the carbon cycle is a bigger player.

The concept behind enhanced weathering is that maybe we could turn up the knob on that geologic sequestration pathway by grinding up rock and then spreading it out so that it can weather faster because it will have more surface area. It's basically like treating the rock like an anti-acid, basically, and spreading it over the earth. I think it's garnered a lot of interest recently because the ultimate resting place for the carbon is potentially more stable than organic carbon in soil, right? Stable meaning longer lasting, basically. That's the primary.

Right, right. It's a more durable place to store carbon than in organic matter, which is, you know, if it's anywhere near the surface where oxygen and water can get to it, ultimately is susceptible to decomposing, right? So that's why people are intrigued by, enhance weathering geoengineering, the catch is that we still don't have many field studies.

And so it hasn't really been proven even at a local level, let alone at scale. And it's probably pretty hard to quantify how much CO2 is actually being removed via that pathway. There are many people working on devising approaches for that. But I would say it's definitely an emerging technology, and it's not yet at a point where it's been fully proven. but I do understand the excitement around it. Right. Okay, let's bring it back to organic world and talk about some of the sort of farming-related practices.

People talk about regenerative agriculture as this broad category, but then more specifically within that, there's a bunch of agricultural practices that are purported to potentially either sequester more carbon in the soil or keep the carbon in the soil longer. I'll maybe bucket a few of them together and then just get your take on what the state of the science is on what we know about how effective these might be. But there are things like cover cropping and agroforestry, no-till farming. How should we be thinking about all those things as of today? Where to start here? There are a whole range of agricultural practices that were originally developed for,

for perfectly good agronomic reasons that aren't actually related to sequestering atmospheric CO2. And that would include cover cropping, which is partly about erosion management and nitrogen management in agricultural soils and maintaining soil fertility, because organic matter is good for soil fertility. Or No-Till, for instance,

which was developed as an erosion control measure, right? Or for that matter, agroforestry, which also has benefits in terms of soil health and erosion control, et cetera, right? So these practices were explored or promoted because they have real benefits in the right context for agriculture. And then what's happened over the last couple decades is that there's been an increased interest in using these practices to also defy climate change. There are difficulties, though. all of these agricultural practices, they yield increases in the amount of organic carbon in soil. And organic carbon is not necessarily a long-lived sink for atmospheric CO2.

And at some level, I think that's the central thing to keep in mind, is that microbes like to break down organic matter. It's how they make a living. And so any one of these practices might succeed in building up some carbon, but the amount of time it sticks around is unclear, in that it will depend on future land use and future climate. And so we really importantly need to think of conservation agriculture as giving us maybe a temporary place to keep some carbon out of the atmosphere, but ultimately it shouldn't be treated as equivalent to a more durable or permanent carbon removal strategy.

So that's probably the most critical thing to keep in mind. Virtual power plants are becoming a reliable way for utilities to manage capacity, but enrolling devices is just the start. What really matters is confidence, knowing those resources will perform when dispatched and being able to prove it from the control room to the living room. Energy Hub's platform handles the full picture, from near real-time forecasting, locational dispatch, and the kind of rigorous verification that holds up when regulators, grid operators, or leadership ask, did it deliver?

Easy enrollment creates momentum, proven performance builds trust. That's why more than 170 utilities rely on Energy Hub to manage over 2.5 million devices delivering 3.4 gigawatts of flexible capacity. See what that looks like at Energyhub.com. We're living through a profound economic shift, and energy sits at the center of all of it. Trillions of dollars are flowing into power plants, transmission lines, battery factories, data centers, but the future of energy isn't shaped by technology alone. It's shaped by markets, by policy, by capital, and by the institutions that connect them. I'm Alfred Johnson, CEO of Crux,

the capital platform for the clean economy. Join me for my brand new show, Critical Capital, as I talk with people deploying capital, shaping policy and building projects. Together, we unpack how risk is priced, how incentives are structured, and how progress is actually made. Listen to critical capital on Spotify, Apple, or wherever you get your podcasts. One of the things that I think is maybe important to distinguish, I feel like with any of these practices, especially if you're trying to then gain some kind of credit or economic value for the carbon that you sequester in the soil as a result of them, there's two different types of uncertainty. Maybe there are more, but at least two that I think of. One is the durability, which, as you

said, is at least in part, if not in large part, a function of future practices on the land, which you, you know, there's sort of legal mechanisms to contract around potentially, but there's inherent uncertainty there because you just don't know what's going to happen in the future. But then there's The other uncertainty, which is how much additional carbon did you sequester in the first place? It's a volume question more than it is a durability question. And I wonder how you think about the degree of certainty that we can have generally today that if I say, okay, here's a plot of land, here's what I've been doing on this specific plot of land, and here's what I'm growing and where it is geographically and everything.

Now I'm going to change one practice. I'm going to stop tilling or pick your practice. How much certainty can we have around the amount of carbon that is additional carbon that is sequestered? And what is your take on the sort of world of measurement around that, which also has its own whole suite of different solutions? Yeah, you know, at some level, the elephant in the room is the additionality question. You know, we, the we meaning the scientists, people like me love to talk about measurement and issues with measurement and how to measure best, et cetera. But I think that all pales in comparison to the more difficult question of what would have happened on that piece of land otherwise, right? Because if somebody was going to be practicing no-till agriculture, regardless of whether you paid them for it, then it's, you know, it doesn't count as a, you know, carbon removal or something that could be traded as an offset or anything like that, right?

and this issue plagues the forestry sector as well. It's just as bad in the soil world. And I personally, I think that challenge swamps the measurement issues. But there are also challenges related to measurement. I mean, we know how to measure soil carbon and how to estimate it, but if you want to know the answer in one particular field, it requires taking a lot of samples. At some level, you can get to.

around that by scaling up projects because basically if you want to get the right answer on average over a large area, you can get away with sort of achieving that with fewer samples. So there are sort of economies of scale when it comes to the measurement side of things. But the measurement practices are not really nailed down yet, at least not in the the protocols that I've looked at, you know, if, you know, if you want to actually get down to brass tacks, you know, one thing that I've griped about before is, is sampling depth, and I've got a piece with carbon plan on sampling depth with relation to soil carbon. And, you know, that, specifically in the case of no-tail agriculture, I think, is really important.

So, you know, there's been kind of a controversy around that. And depending on who you talk to, maybe it's a tempest in a teapot, or maybe it's a big deal. But, you know, basically shifting tillage regime, it means that not only are you changing the biology of the system and the rate at which carbon flows through it, but also changing the vertical distribution of carbon because tilling soil mixes carbon. and it also influences rooting depth. And what that means is that in, at least in certain environments, particularly in places like the Upper Midwest, for instance, changing from a full-till regime to a no-tail regime, which is supposed to sequester carbon,

can actually mean that you lose carbon deeper in the soil. And what that means for measurement is that you have to sample deeply enough that you can count up the gains you get at the surface and the losses you get below so that you can get a full accounting of the net effect, right? And it's still not clear exactly how deep we should be going, although it's probably deeper than 30 centimeters, which is the kind of minimum that people require. So maybe that answer is quite about uncertainty,

but I don't think that the current approach is to monitoring are totally nilled down, although I think we can solve those problems because they're technical problems, and the additionality issue is the bigger one. All right, so putting on your excited scientist hat, maybe it's the only hat you wear, but Oh, boy. Well, I'm curious where you think the coolest new science is taking place in and around and soil carbon. You know, we talked a little bit about some of the more novel stuff like enhanced weathering.

We haven't talked about, and we talked about some of the more sort of like practice, agricultural practice-driven stuff. we haven't talked about some other areas where folks are doing work, things like biotaur application to soils and some more like novel inorganic carbon maximization and stuff. But like what gets you excited? What do you think is really cool that you're seeing science built around? Yeah. I mean, I think what I'm most excited about isn't a particular practice or strategy or technology. It's more a way of thinking about how soil carbon works.

that could kind of bleed into all of these applications. And, you know, I guess, to back up a bit, the way we've thought about soil carbon has changed a lot, soil organic carbon has changed a lot over the past several decades. You know, it used to be the case that the sort of dominant theory was that soil organic carbon persisted in soil because it had intrinsically resistant chemical properties that made it hard for microbes to digest. And that idea has fallen out of favor because it's not really supported by the evidence because we find compounds that are potentially really easily

digestible by microbes that have been in the soil for a long time. So then the question is, why do they stick around as long as they stick around? And if we could answer that question, it would help with forecasting future climate because soil is huge, just in a totally unmanaged sense, knowing how climate's going to influence soil and vice versa, it's hugely important. But it would also be really helpful for evaluating the durability of any scheme that increases organic carbon sequestered in soil, right? So getting a sense of what controls the persistence of organic carbon is this essential question, right? So what gets me excited is that people are increasingly thinking about that quality of persistence in a more interdisciplinary way that links with the geosciences.

And that's what I'm really excited about. And rather than thinking about organic matter and soil as being controlled entirely by biological processes, We're learning that minerals in soil play this huge role in controlling the persistence of that organic carbon because they can encapsulate it or provide surfaces that the carbon sticks to or release metal ions that sort of co-precipricitate with the carbon and make it harder for microbes to get at because they've basically created these organometal precipitates. And all of that interactivity is really fascinating because it actually links the processes of soil formation and weathering to the biology in this really fascinating interdisciplinary way. So there are people at universities and research institutions all over the world that are studying various aspects of that sort of biogeo interaction.

and the role of minerals and the inorganic part of soil in regulating carbon cycling and vice versa, the role of biology in accelerating those reactions. All right, so I guess final question. A lot of all of this thinking and accounting around soil carbon relies upon modeling, ultimately, because we're not measuring everything all the time and certainly can't measure the future. So what type of modeling are we doing? How sophisticated is it? Is it well set or is it problematic? Give me a sense of the world of soil carbon modeling. Yeah. It's a – it's kind of a thorny topic at some level.

The history here is that people first started modeling soil carbon in a really quantitative way in the mid-20th century. And so this was in an era when people still thought of soil carbon as largely being just dead plant material that was hard to decompose. I'm simplifying a bit when I say that, but that was sort of the dominant paradigm at the time, right? And the way they represented that is that they basically did it in a very conceptual way, which is that they, scientists had figured out that some soil carbon is very bioavailable and it cycles quickly and some of it is less bioavailable and so maybe it's more recalcitrant is the word that was used for it and because of its chemical properties or perhaps for other reasons and so it cycles more slowly and so they conceptually they divided the amount of carbon in the soil into these

pools, and they assign different decay rates to them, and basically represented the return of carbon to the atmosphere from soil organic carbon pools, the way you might model radioactive decay, as a first-order exponential process. So basically, the amount leaving any given carbon pool is a function of some intrinsic turnover rate that's modified by environmental conditions like temperature or moisture. And that's a pretty hand-wavy way of representing the system, but it sort of worked at capturing, you know, in a broad-brush way, some of the dynamics and the spatial patterns, right? And so those models really got developed in the, you know, starting in the 70s through the 80s and into the 90s and kind of coalesced around what we call first-order soil. carbon models. And so, like,

Descent is an example of a model like that, or DNDDC, right? And those became the core of the way soil carbon is represented in Earth system models that are used to forecast climate and are really the workhorse still today. And are importantly

central in sort of soil carbon valuation schemes. And so they're, you know, they remain really important from an applied standpoint. But the tricky thing is that our understanding has evolved tremendously since the

1980s and 90s, and there's been this big paradigm shift on the more empirical side to really emphasize the role of microbes as actors in the system. They generate the enzymes that break down the organic matter. They're ultimately the sort of linchpin that connects the organic matter to the atmosphere because they're the ones that are breaking it down and releasing it as CO2. And also the role of minerals in interacting with organic matter and stabilizing it. And when you start to represent a system like that, you end up with models that have very different behaviors than the first-order models. And they come up with very different predictions.

For instance, a first-order model would predict that if you add more carbon to the soil, the amount of carbon stored in the soil will increase in a way that's basically linear at steady state. But a model that has microbes in it will not make that prediction. And so our understanding

has sort of outstripped the models. And so the models that are being used to make projections about carbon sequestration in soil or to come up with estimates for baselines for those calculations are

essentially outdated, which is not to say that they're wildly inaccurate, but they don't reflect our current understanding of how soil actually works. And maybe they didn't even really do that in the 80s and 90s, and people knew it, and they were just looking for a solution to the problem, but we still haven't reached a satisfactory place where the math represents our thinking. And so it's going to be an interesting process, seeing how the newer models that incorporate that complexity evolve and whether they get enough traction that they can push out the old-fashioned ones. Right. Well, as usual, in any conversation that I've had around soil carbon, I feel like I both know more and no less than when we first started chatting. I've done my job then. That's right. On

balance, it's more, though. So thanks, Eric. Really appreciate the time here. Yeah, of course. Eric Slesserov is a staff scientist at Lawrence Livermore National Lab, where he studies soil carbon. Well, what did you think? We got a bunch of comments on the previous episode on soil carbon markets. Folks have strong opinions on it. As you can imagine, I'm sure that is true of the science as well, so we welcome your feedback. You can find us on Twitter at At CatalystPod. You can also find me there. If you like the show, as always, go over to Spotify or Apple Podcasts and leave us a rating and review. This show is a co-production of PostScript Media and Canary Media. You can head over at canarymedia.com for links to more info on today's topics. And as always, PostScript is supported by Prelude Ventures,

the venture capital firm that partners with entrepreneurs to address climate change across a range of sectors, including advanced energy, food and agriculture, and definitely soil carbon stuff, transportation and logistics, advanced materials of manufacturing, and advanced computing. This episode was produced by Daniel Waldorf and Dalvin Abouaji, mixing by Greg Vilfrank and Sean Marquand, theme song by Sean Marquand. Our managing producer is Cecily Meza-Martinez. I'm Shail Khan, and this is Catalyst.