0:33 Intro. [Recording date: May 18, 2018.] Russ Roberts: My guest is journalist and author Moises Velasquez-Manoff. He first appeared on EconTalk in March of 2014 discussing his provocative book, An Epidemic of Absence--his look at the idea that avoiding germs and parasites in modern times may have been the rise of very subtle immune disorders--asthma, various allergies. Today we are going to talk about a recent article he wrote in the New York Times--can dirt save the earth? And, if we have time we'll circle back to the story of germs and parasites. Moises, welcome back to EconTalk. Moises Velasquez-Manoff: Thanks for having me. Great to be back. Russ Roberts: No, your story in The Times starts with a little bit bizarre; and for me, as an economist, a fascinating story, even though it doesn't have that much to do with economics. But what it has to do with is complexity and emergent order, which of course I'm always interested in--as listeners know. Tell the story of John Wick and Peggy Rathmann--their cows on their porch of their house and what they discovered as they tried to live a wilder lifestyle on their ranch in Marin County-- Moises Velasquez-Manoff: Right. So yeah. So, in the late 1990s--so, Peggy Rathmann is a children's book author. And probably any parents out there, seems like anyone owns a copy of Good Night, Gorilla, including us, which is this classic children's book. She wrote that book and numerous others. So, she lives in San Francisco--lived in San Francisco in the late 1990s--and they needed more space because their apartment was getting full of their illustration. And her husband, John Wick, was then a construction foreman. So they started looking for places up north of San Francisco in Marin County and found this ranch of over 500 acres, which they ended up buying; and they bought it because they wanted--basically it had this huge barn that they wanted to turn into an illustration studio. And it gave them a lot of space. Ultimately that never panned out because the barn was oriented wrong for the light or something: it never really worked out. But, what did end up happening was that--so they were just enchanted with life up there, this bucolic life, lots of animals, and gophers; there were even mountain lions wandering around, as there are out here in the West. And, they decided to turn their land back to what they thought would be wilderness. So, it had--all that country is sort dairy country, or cow country. It's been that way for like a hundred years. Russ Roberts: Not exactly wilderness, by the way. One of the stranger things is when you go north of San Francisco, you do see, on Route 1, you do see cows grazing. It's 1 or 101. Route 101, I think. Moises Velasquez-Manoff: That's right. Russ Roberts: You see cows grazing by the side of this road. Kind of wild, but they are cows--not so wild. Moises Velasquez-Manoff: Yeah. No. Absolutely. It's a very agricultural landscape, and specifically dairy-oriented: for some reason, that climate produces--you get the marine zone wetness coming off the ocean, so even though it doesn't rain, like, except for 3 or 4 months of the year, you still get good grass growth there. I think that's one reason. At any case, so, some rancher had rights to their land, or the previous owner had sold rights, grazing rights. So they revoke those rights; they kicked the cows off the land in pursuit of going back to wilderness. And what happened was the landscape started changing right away, turning into something that they did not like. Which was, a lot of invasive weeds started moving in, and brush started moving in. I mean, if you know about ecological colonization theory, it's not that surprising. So, what happens is like, grasses are the first colonizers of a disturbed landscape; then brush moves in; then maybe some scrub--depending on what the climate allows for--some scrub trees. And they are probably the oak scrub forest or something naturally. And so, really what they were seeing was this sort of recolonization, without the grazing pressure, of these different plants which they didn't appreciate. Because, you know, you walk out to this landscape of rolling hills, verdant pasture; and all of a sudden it's becoming clogged with all these opportunistic weeds. Right? And they didn't really like it that much. So, they--first of all, John Wick went out and tried to actually, literally, kill some of the weeds back. There's one called the Woolly Distaff Thistle, which is--it's an invasive--it looks like a marigold on steroids. We have them in my backyard, too. It's prickly and has these yellow flowers--but it's a really powerful plant. It just moves in; it shoots in, and it's hard to like actually pull with your hands because it has these kind of spines on it. So, he was using these kind of herbicides and all sorts of stuff, trying to pull it out, mow it. Of course, none of that works. Because you are dealing with sort of this force of nature that's not--it's not sensitive to that kind of intervention. So, then they meet this rangeland ecologist, Jeff Creque, who says, 'Well, what you should do is instead of focusing on what you don't want to be there, trying to beat it back, you should focus on what you do want to be there.' And, so he looked at the hillsides and he said, 'I bet,' this is actually not in the article but he said, 'I bet that there are seeds in this dirt still from the old, perennial grasses that used to exist in California, pre-European contact.' So, like, in California in general, there have been grasses introduced with European, basically with cows when the Spanish first and then with the United States. So, annuals grow and then die in one year; and perennials are those more big, bushy grasses that live year after year; and they have these really deep root structures. So, he said, 'I bet there are perennial seeds in there, still, if you just graze the landscape in the right way.' So, yeah, so he said, 'If you bring back cows it could actually help with this problem that seems to have emerged after you kicked cows off.' Like, so, just to give some background again: Cows are generally, from the conservationist standpoint, are blamed for denuding landscapes; for desertifying them. And for good reason. I mean, that has happened around the globe, everywhere, throughout human history, where overgrazing has basically turned semi-arid landscapes into deserts. You know, all around the Mediterranean rim, and basically almost anywhere, throughout the American West, and anywhere that wasn't moist. And cows can be a horrible sort of environmental destructive force. Russ Roberts: It's like--we had the same issue in Yellowstone, which I've written a little about and I think it's such a fascinating related story, where they get rid of the wolves, because people are scared of wolves, I guess; ranchers don't like 'em near the Park; the elk population grows tremendously, and as a result the elks denude--and eat down to the ground basically anything, all kinds of stuff, riparian systems around creeks and streams. And that ends up killing the beavers, because they have no stuff to make dams with any more. So you get this crazy thing that wolves are connected to beavers. If anything, you'd think wolves would eat beavers. And so, fewer wolves, more beavers. But if works the opposite way. And, you know, cows don't have any predators. So if you do keep them in one space, they will kind of eat everything. Well, they have predators; they have us. But I mean, if people want to keep a herd going, they are going to kind of eat a lot. Moises Velasquez-Manoff: Right. So, Jeff Creque is basically making the point that if you graze cows like wild herbivores that are pursued by predators--so, the term is 'mob grazing.' That's one term. And the idea is just to keep 'em moving across the landscape. Don't leave them in one place too long. Keep a tightly packed herd, the way you can imagine a herd of buffalos pursued by those buffalo-wolves that we used to hear about back in those--those gigantic wolves that used to hunt buffalo on the plains-- Russ Roberts: 15, 20 feet long. Yeah. Hmh, hmh, hmh, hmh, hmh. Moises Velasquez-Manoff: What, the wolves? Russ Roberts: Yeah; I'm kidding. Moises Velasquez-Manoff: I'm not talking about the dire wolves. Russ Roberts: Kidding. Kidding. Moises Velasquez-Manoff: Well, it's funny, actually--I was reading--this is a little bit of [?], but I was reading Laura Ingalls Wilder, The Little House on the Prairie, to my daughter a few months ago. And they saw some of those--you know, when those settlers are moving onto the Plains, they still saw some of huge wolves that were remnants of an older population--they were just getting killed off--that used to hunt buffalo on the Plains in the Dakota. In any case. So, he brings the cows back and then manages them in this new way: Instead of just letting them free-roam, basically, he cut up his land, if I recall correctly, like 67 different separate lots that he moved them between. So that each lot would get intensely grazed for a very short period of time. And, sure enough, the landscape responds. Their pasture returns. And, actually, what's interesting, is he tells me, John Wick tells me, that weeds actually taste very good to cows. So, the weeds are like the first things to go. I mean, in a way it makes sense: Like, any plant that has prickles and stuff all over it is a plant that probably tastes pretty good. That's why it has prickles all over it, to defend itself. So, the landscape is reverting back to what they considered to be, what they really wanted when they thought of wilderness. Which is not at all wilderness. Right? It's more of a graze ecosystem.

10:14 Russ Roberts: It feels like wilderness to us, because we don't know what the real thing was. Moises Velasquez-Manoff: Yeah, but honestly, if you go back to pre-, like the Native American times, that's what these ecosystems were. They had large grazers like elk. And they had lots of predators, like big cats and bears. There was grizzlies out here in California. Russ Roberts: And humans. Yeah. Moises Velasquez-Manoff: And humans, of course. And pre-native American, there were even larger grazers. You know? There were these mastodons, and the mammoths. I'm not sure which ones were out here. But, huge grazers were out here shaping the landscape with huge predators following them. So, this is what exists when people don't interfere. Long story short; I'll fast forward here. So, they become curious about--Jeff Creque is very interested in climate change. He's worried about it. He thinks--he's interested in the idea that you can get carbon into the soil from the atmosphere. And basically how that would work was the plants, of course, capture carbon dioxide during photosynthesis. And, they use the carbon to build their own tissues, as well as to, they excrete sugars into the soil to feed micro-organisms, that then, in exchange for those sugars give them other nutrients that the plants might not be able to get on their own. So, he urges John Wick to get in touch with the soil scientist at U.C. Berkeley, Whendee Silver, and they basically come to an agreement where she's going to study their land and see if they are getting any carbon into the soil, doing what they are doing. Russ Roberts: And the argument-what would be the logic? Because they've got a richer grassland now? Moises Velasquez-Manoff: Yeah. Russ Roberts: They'd maybe absorb more carbon from the air nearby, and that carbon would show up either in the soil or the plants themselves. Moises Velasquez-Manoff: That's right. And there is--there is a whole sort of--well, there is an argument out there that I did not go into in this article. But, I guess its major proponent is a land manager named Allan Savory. And he gave this TED Talk--he's very influential in ranching circles; very controversial in scientific circles--mostly because the evidence of what he says is possible doesn't exist yet. Russ Roberts: Yeah, 'We'll find it. Give us time. We'll make it up if we have to.' Moises Velasquez-Manoff: But he makes his argument-- That's where we are, kind of. So, he basically argues that if you just graze right in this way, this mob-grazing way, which he calls 'holistic management,' that you can actually--we can deal with climate change. You can [?] the world's deserts, and sort of--it's the opposite of what most conservationists think about cows, which is that we should get rid of cows because they not only denude the world, semi-arid regions; they also belch methane, which is a greenhouse gas that's about 30 times more powerful than carbon dioxide. Russ Roberts: But the argument here is that cows are going to allow healthier--even though they themselves might not be so great, they are going to clear a path for some really good things to grow in the soil, and improve the soil so that there will be less carbon in the air. And then it's an empirical question of whether they are a net positive or negative. And then there's another empirical question of whether you can get those benefits without cows, somehow. Moises Velasquez-Manoff: Yeah. So, I think fundamentally, if you back up: The premise that grasslands can capture huge amounts of carbon from the atmosphere and put it in the ground is absolutely true. Some of the richest soils that we have are, were formerly grasslands. Like, the Great Plains. Like the Midwest. Like the Ukrainian Steppe. These were all grasslands before we plowed them up to plant stuff. And that, like, that is it, like 7 feet of topsoil or something, in Iowa? Like some amazing amount. And that soil is just incredibly rich? Those same ecosystems also hosted huge wild grazers. Right? I mean, there were just herds of, millions of buffalo running up and down the Great Plains. Russ Roberts: Lewis and Clark, what they saw when they went there. Moises Velasquez-Manoff: That's right. And, in Eurasia, it was, maybe horses; I mean, since there was this sort of human footprint it was a little bit bigger there. But there were also huge grazers there, as well. So, it's fundamentally true--there's also this Paleobotanist at the University of Washington, if I remember correctly, Gregory Retallack, who argues that in deep time, the co-evolution of large grazers and grasslands became so efficient at pulling carbon out of the atmosphere that it actually reduced the amount of carbon dioxide in the atmosphere such that it triggered the ice ages, which begin around 2 and a half million years ago; before that there were no, sort of, these periodic glaciations that we call the Pleistocene. That, they weren't happening. Right? Earth was kind of in a different sort of phase, where it was just a lot warmer all the time. So, he makes this argument that it actually cooled the earth and caused this, and these periodic glaciations. So, I think that's fundamentally true. And when we think about grazing and grasslands. But, whether or not cows, which are domesticated animals, can do, replicate, what happens in nature is, you know, still an open question, I think. Right? This is this idea that's out there that John Wick and Jeff Creque were interested to see if they were doing. And, actually, I should point out that they discovered that it wasn't happening. There was not carbon getting into the ground from grazing. So, what ends up happening--I'll back up a little bit from that point--is that they start their--Whendee Silver starts their studies with a series of just baseline measurements in Marin and Sonoma Counties of rangelands, just to get a sense of how much carbon is there to begin with. Right? In the soil. So, they dig these 3-foot long soil cores out of the ground and examine them. And, what she discovers is that dairies--dairy farms--have a lot of carbon in them. And it's very recent carbon. Like, it's got there recently. It arrived into the ground recently. And, so they go around asking, 'What are you guys doing different on these dairy farms?' And what they do is they: Dairy farms, they milk their cows; they take them to a central shed. And they have a lot of manure they have to deal with. It's a huge problem, actually, in dairy farming, in the sense that you just have to manage a lot of manure. And they use water to wash it away. And so they end up with this kind of slurry, this manure slurry. And what they did, a lot of those places, a lot of those farms, is they sprayed it back on the land as a fertilizer, in a way as a way to manage it. So they were basically--what she discovers is that there are things you can do to your land that increase the carbon content of the land. Right? And that dairy farmers are already unwittingly doing this. So, they decide: Maybe we can replicate this--John Wick. He says, 'Maybe I'd like to be able to replicate this, but I don't want to use cow manure. Because cow manure releases lots and lots of methane, which is a powerful greenhouse gas, and lots of nitrous oxide--an even more powerful greenhouse gas.' So the numbers are like methane is around 30 times more powerful than carbon dioxide; and nitrous oxide is around 300 times more powerful. So, they--Jeff Creque--he had been an organic farmer, so he was very familiar with compost. And compost is basically just--it's food scraps or shredded trees or any kind of organic material, really, that's been decomposed, partly decomposed, by microbes--by--these are microbes that are not anaerobic. So, like, the key to composting is, of course, anyone who has a backyard compost pile knows, is you have to constantly sort of turn the pile to keep it aerated--to keep oxygen in there. Otherwise you start getting really nasty smells. And, from the scientific point of view, you start getting those powerful greenhouse gases. So, they put a bunch of compost--about half an inch--over a few acres. But what they discover over the following years is that compost seems to act like, on one hand, like a kind of fertilizer--a long, slow-acting fertilizer on the landscape. So that it supercharges the grass growth. This is rangeland. This is land that is being--you know, it's grass, it's being grazed at the same time. So, it makes about 50% more grass grow. Which is great. It's great for anyone who has cows on the land--which John Wick does have. And it causes--it allows more water to be absorbed or held in the soil, because the more organic material you have in the soil, the organic material acts like a sponge and holds the water. So there's more water stays in the soil. This again, this is grassland that gets water only in the winter, really; and then, the rest of the summer here in California, on the Coast, we don't really get any rain. Except we get this marine layer moisture that comes in, but that's it. And then, what's happening also is that carbon is going into the ground at an incredibly rapid rate. So, and in untreated control plots, the carbon is getting lost from the ground. This is just--nothing is happening on the land; land is being grazed; carbon is seeping out of the ground. And no one is really sure why this is the case; but it's likely that it results from that transition I mentioned earlier of the kinds of grasses that grow there: from the old, perennial kind, which are--you know, they grow, year after year of the same plant, and they have really deep root structure, so that, those deep root structures push carbon into the ground, or deposit carbon in the ground--and annuals, which don't have these deep root structures. So, the landscape had gone from perennial to annual. And that probably causes, caused over time, a loss of carbon. But, on the treated plot, the opposite happened. Carbon was getting absorbed. And most of that carbon--so, compost is very rich in carbon. Obviously, anything that's organic has a lot of carbon in it. It also has nitrogen and a lot of other stuff in it. Um, but the carbon that was going in to the treated lots was, most of it was not from the compost. Most of it was from the air. Meaning that: She had--she, being Whendee Silver--had basically caused the ecosystem there, in that treated plot, to become so, to accelerate at such degree, to accelerate photosynthesis, that there was just carbon being pumped into the ground.

21:04 Russ Roberts: So, I'm going to pause you here, because it's a little bit complicated. And I just want to let--do a little reset here for listeners. First, I want to point out something you point out in the article, which really, an incredibly beautiful idea, that of course the carbon that we use for energy purposes, like oil, is the result of this process from billions of years ago. That, plants absorbed carbon, died, went into the ground, and eventually turned into petroleum. Correct? Moises Velasquez-Manoff: That's right. I think oil actually comes from some--but, I mean, fundamentally, yes, you are right. But oil comes from a marine process. Coal comes from a wetland process. But, yes, you are fundamentally correct. All that carbon came from photosynthesis and got deposited somewhere. And then got buried at some point. And then was fossilized after it got buried and became this fuel that we now power civilization with. Russ Roberts: Right. And we create civilization with it. And we pump a lot of it into the air as a result. And, it seems to be getting a little bit warmer. We can debate about how much. I'm a lukewarmer. The meaning--I think there's some warming; I don't know whether it's catastrophic; but I am worried about it a little bit, I think, because you should always worried about the downside risk that could be catastrophic. I learned that from Nassim Taleb. And common sense. And so, that's just a beautiful thing, that we could recreate that, use that same process, to get the carbon that's in the atmosphere now back into the ground. It's kind of a cool thing. The economics of it, of course--and by that I mean not the financial part, but the big picture economics--is: This does strike me as--my favorite Hayek quote: "The curious task of economics is to demonstrate to men how little they really know about what they imagine they can design." So, part of this--your article has this really crazy idea that somehow we are going to re-engineer the soil to solve this other problem we've got over here. And we don't really understand the whole thing, really that way. We get glimpses of what's going on. We run this one study--Whendee Silver's done it--that looks encouraging, this incredible reduction of carbon. But we don't know if it's going to scale. We don't know what the other effects are. We don't know if by spreading compost in a really wide range across all kinds of different terrains, what could happen. But, the bottom line is this encouraged people to start thinking about one way to fight global warming, and climate change: Which is to change farming rather than, say, cars. Which is really interesting. Which is why we are talking. Moises Velasquez-Manoff: That's right. And it's often these, these modifications in the agricultural world, are a lot cheaper than, you know, photovoltaic panels on all houses, or all this more high-tech stuff. Because, you are just tweaking how you do what you already are doing, in some respect. And I should point out that, um, this is often thought of in the circles of people, the proponent circles, as being beneficial to the farmers themselves-- Russ Roberts: And we're not going to punish them-- Moises Velasquez-Manoff: That's right-- Russ Roberts: for their bad use of cows and therefore put a big tax on cows, or force them to change. We're going to find a win-win, is the ideal. Moises Velasquez-Manoff: Well, it's more that, um, by getting carbon in the soil, you actually improve the efficiency of fertilizers. So, like, you need basically less fertilization of synthetic fertilizers the more carbon you have in the ground-- Russ Roberts: They are expensive-- Moises Velasquez-Manoff: That's right. You save money. And there are a bunch of other things, as well. Like, I mean--it's interesting because, a lot of this stuff was clearly known before the advent of the modern agricultural tool kit. We know of synthetic pesticides and fertilizers. This is what farmers had to do before, you know, the 19th century when [?] Russ Roberts: spread a lot of manure. Yeah. Moises Velasquez-Manoff: But they knew that you had to return all organic material to the land. Otherwise your land would stop producing. Right? And so, like, there are these--there were these revolutions in Europe, for example, where they sort of centralized the cow barn to all--in terms of all the fields--so they would be in the middle of the whole operation, so that they could get the manure back to the fields easily. Right? Russ Roberts: It's like the spoke and hub airline[?] system. It's great. Moises Velasquez-Manoff: Right. Right. Exactly. And they were often getting human waste back to the fields. I mean, there is a point where there was competition for the nitrogen in human waste for producing making gunpowder with it, rather than putting it back in the fields. Right? In Europe. Russ Roberts: I like your term--I think you mentioned it in one of your [?]--'humanure'. I don't know how to pronounce it--hu-manure. But that somehow--there are other words for it; we won't use them on the program, but that's an attractive name for it. Moises Velasquez-Manoff: The other term is 'night soil,' which is used in the early 20th century, which is just, whatever is in your chamber pot, which is another nice euphemism, went back on the garden in the morning. Right? And this is part of how agriculture worked, because otherwise your land would, after repeated growing, your land would start to lose its fertility and nothing would grow there. The other aspect of this was that you would rotate what you did on your land: crop rotation. You would change what grew where, because different plants both feed the soil in different ways and also take different things out of the soil. And you would also rotate in grazing with your farming. So that, you would let one field that, let's say, grew corn last year, you would just let it go to pasture and graze on it for another year; and then plow it the following year. These are all techniques to maintain fertility. Which, I guess they are just sort of coming back, because after almost a century of doing everything synthetically, a lot of the land is, in the United States and in the world, in the developed world, is exhausted-- Russ Roberts: is tired. You have an amazing statistic in here which I just never imagined to be the case. I assume it's true. "More than one third of earth's ice-free surface is devoted to agriculture." Part of the reason it's hard to believe is the United States, which of course has, for better or for worse, probably the world's most productive agricultural system--in certain crops for sure; I don't know how widely that's the case. But, we've got some great--we've got great machinery, to keep the price down; and we've got great synthetic stuff to keep yields high. And we have great seeds; and we're at the cutting edge of everything. But most of the world is not. A lot of the other parts of the world are not, and they need a lot more land to grow food. And it just--right? It's just surprising that that-- Moises Velasquez-Manoff: That statistic also includes rangeland; and about two thirds of what we do with land in the world is grazing it. Just like one third of that is actually used to grow crops. Because, most marginal land is used for grazing--like the hills and stuff, you can't plow up. That's just--you let cows roam on it; and especially in poor countries, you are able to get another protein source from that grass, that land from which otherwise you wouldn't be able to get anything from. Russ Roberts: Right. Cool.

28:42 Russ Roberts: So, where are we? So, this experiment gets done. Talk about where--I just like that story; for a lot of reasons, I like it, because of the unintended consequences part of it: The fact that these people hated these cows and thought that by getting rid of them, they'd make their land better when in fact their land got, to their eye at least, worse. The other thing I like, I just want to mention because I don't want to miss this chance, Moises, is that your research interests and interests as a writer strike me as united--I'm sure; I assume you've thought about this, but maybe not--so your first book--I don't know if it was your first one: An Epidemic of Absence: A New Way of Understanding Allergies and Autoimmune Diseases is about the microbiome; it's about our gut. And this article and other stuff we are talking about is about the soil. And on the surface they have nothing to do with each other. But, they are united in a couple of ways. One way is that they are both about complex ecosystems, emergent orders that are not easy to look at. Moises Velasquez-Manoff: That's true, yeah. Russ Roberts: So, the soil is underneath the ground; and my gut is inside my body. And so, they are complicated systems; they are hard to get at. And as a result, there's all kinds of things to be discovered there that may not be obvious and are connections you don't get to see and might not appreciate. So, I don't know--there's a symmetry in your work there that I love. And then there's cows. Because, cows are good for the soil, and they may appear to be good for helping us fight autoimmune disorders by introducing parasites and other things into our microbiome that we've lost as we've moved away from agricultural life. If we have time, we'll come back and talk about that and the gut. But I just wanted to point those out. Moises Velasquez-Manoff: Yeah. Well, actually, they're more closely linked, these two big themes in my work, in the sense that the microbiome of the soil is also what's responsible for the carbon sequestration. So, the plants--basically, what plants do is they capture carbon from the air, and beside making their plant forms, their actual tissues, they create sugars with a huge amount of the carbon that they get from the air. And those sugars go right into the ground to feed the microbiome of the ground. So, there is this whole microbiome in the ground--I mean, this whole ecosystem really in the ground, that's being fed--the plants are basically working as pumps. Carbon pumps. This is how it was described to me by, I think, Whendee Silver, I remember. But, the purpose of the plant in this big ecosystem is to just pump sugar into the ground, or other kinds of carbon, long carbon chain molecules, that are then consumed by this incredible array of life in the soil, that then returns other nutrients in exchange for those sugars. But that is the carbon pathway of how you get carbon from the air into the ground--is, basically, by passing it through all these life forms. And huge chunk of those life forms are microbes. In the soil. So, basically, healthy soil is basically about a healthy soil microbiota[?] Russ Roberts: It's all about the gut. Whether it's inside you or underneath the ground. It's all about the gut. Moises Velasquez-Manoff: That's right. You can think of the soil microbiome as a kind of analog to the gut microbiome, in a way. It sort of powers everything. Like you said. And yet we don't pay much attention to it. We haven't historically. Russ Roberts: Well-- go ahead. Sorry. Moises Velasquez-Manoff: Well, I was going to say that the advent of genome sequencing technology is letting us see both these microbiomes in a way we absolutely could not see them in times past. That's another part of this story. Russ Roberts: When I was a little boy, I did not grow up in farmland. I grew up in suburban Massachusetts, mostly, in Lexington. And we'd go out--we'd play in the dirt. And we loved worms; and I like to fish; so we'd dig up dirt and find worms in there. And if you'd asked me, since I didn't have a farming background, 'What's underneath the earth's surface?' it's--well, it's dirt and worms. Well, of course, I'm getting there. But the idea of the richness of soil, the chemical composition of soil, the difference between dirt, clay, and, say, loam--a rich, fertile soil--people for most of human history were obsessed with it. We're not really that involved with it. I'm going to read one more thing from your article, by the way; and then we'll get back to the policy stuff. And I hope listeners are enjoying this, because to me it's extremely interesting. But we'll get to some policy implications in a second. It says--you are talking about when they brought the cows back to the Marin County acreage that Wick and Rathmann, the children's book author at their ranch. It says, By summer's end, the cows, which had arrived shaggy and wild-eyed after a winter spent near the sea, were fat with shiny coats. When Wick returned the herd to its owner that fall [Russ Roberts: This is the herd that he had grazed on his land to try to get it back into shape] collectively it had gained about 50,000 pounds. Wick needed to take an extra trip with his trailer to cart the cows away. That struck him as remarkable. The land seemed richer than before, the grass lusher. Meadowlarks and other animals were more abundant. Where had that additional truckload of animal flesh come from? And, of course, the answer is they were eating carbs. Which brings us back to other EconTalk episodes. Moises Velasquez-Manoff: That's right-- Russ Roberts: Carbs and weight gain. So, I just thought I'd bring that in. I loved that. So cool. Moises Velasquez-Manoff: Yeah; that's right. And, of course, those carbs were coming from the sky. I mean, that's the whole--the carbon cycle, that we often forget. But the carbon cycle basically begins with photosynthesis. And then you eat the plants that have captured the carbon; and then plants eat those--I mean, other animals eat those animals, on down the chain. And they decompose, go into the dirt; other plants grow out of it. And eventually all that carbon is released back into the atmosphere--that, the carbon represented in that first plant that grew that was eaten by the cow. But that's the short-term carbon cycle right there.

34:38 Russ Roberts: So, what is this--this is really cool. It's fascinating to me; it's interesting; it's a beautiful example of the seen and the unseen, a theme I love in economics: emergent order, things that are complicated and related to each other in not-obvious ways. Which I love. But, is it important? Is it really a potential mitigator of climate change in any way? And, who is skeptical about it? Why are they skeptical? You know, obviously, if it was good farming practice across the board, it would just happen. Is there something that people are trying to encourage artificially? Are there subsidies, or various regulations? And, what's the potential? What do you think? It's a great story. Is it--is it of any meaning? Moises Velasquez-Manoff: So, carbon farming with compost is just one method of carbon farming. And carbon farming is the idea that if we can get carbon into the air, into the soil or into just living trees or plants, you know, woody material that's not the atmosphere, right? So, well, so, there are other methods of doing this that don't involve compost, like, you know, cover crops. Some of the older stuff that I alluded to earlier--the older agricultural methods that, because in the past, when we didn't have synthetic fertilizers and farmers who naturally obsess with soil health--you know, they maybe call it that. They sort of developed all this stuff. And so, there's a movement now, afoot, independent of what John Wick and Peggy Rathmann are doing, sort of encompassed under the moniker 'Regenerative Agriculture,' where they are trying to--a lot of the agricultural land in the world is exhausted, because it's just, you know, we've basically plowed the hell out of it and doused it with herbicides and pesticides, and fertilizers, when it was losing fertility. So, the idea is to sort of regenerate some of the soil. So, I visit one other farmer who is doing this stuff as a way to just farm more efficiently. And, um, to answer your question: because, we have to think of this as a suite of practices, right? It's not just compost. There is a whole number of things you can do. And the idea is to get farmers who are cultivating crops to take up some of these practices. And these guys--there's a number of people around the States now doing this--Gabe Brown, I reference: he's sort of a pioneer--they say that they are producing crops with fewer fertilizers, fewer pesticides. These are not organic heads. You know. There's no ideology here. What they are trying to do is farm more efficiently so they can make more money. Right? And-- Russ Roberts: Nothing to be ashamed of there. Moises Velasquez-Manoff: in being more efficient-- No, no. These are not--not that there is anything wrong with California hippies. But these guys are not California hippies. They are sort of middle-country, just regular farmers just looking for ways to do things. I mean, farming is a difficult business. The profit margins are so, so slim. Right? And so, anything you can do to keep more of the money that you generate is good. And what these guys do, it sounds like I've talked to a few of them, is that by focusing soil health, they reduce their pesticide use, their fertilizer use, their herbicide use. You know, they get basically nitrogen into the soil by using cover crops--cover crops like legumes. Legumes have the nitrogen-fixing bacteria in their roots. So you get that in there naturally without having to purchase synthetic fertilizer. And I know people will say fertilizer is cheap. But I also--you know, the profit margins are so slim, anything you can do is going to help you out. And so, what they do is they produce crops, they say, for about 20% less than conventionally-farming people. And so you see[?] realize[?] everyone doing this. What they are doing, right? Russ Roberts: Let me guess--one reason is these are smaller farmers than the largest farmers in America--I assume is part of it. Moises Velasquez-Manoff: That's part of it. But that is not the answer that they give. The answer that they give is that, people don't want to change the way they've farmed for, perhaps, generations. And, in a way admit--they know, and admit in a way that they made a big mistake-- Russ Roberts: Yeah. Sure. That's no fun. It reminds me of the doctors who thought women were dying in childbirth because the windows were open, and that brought in bad air. Right? And, while, what's his name-- Moises Velasquez-Manoff: Semmelweis-- Russ Roberts: Semmelweis,

God bless him, although it took way too long for people to agree to it--he said, 'Maybe you should just wash your hands.' He did a little, quick experiment, showed it; and they weren't convinced. Because it was one experiment. It was a small sample. For him it was so obvious, he didn't even to make it larger. But, for them, it was like, 'You're telling me that I've been murdering women because I went for the morgue, [?] in childbirth to go deliver her baby, and you're telling me for the last 30 years of my life, I'm a killer.' And he just couldn't face it. I think that's a huge part--there's a huge psychological part to that. Yeah: You've been an idiot, in this case; and maybe you've damaged the environment, too. It's no fun. Moises Velasquez-Manoff: And, by the way, Semmelweis ended up dying in an insane asylum. Russ Roberts: Yeah, I forgot about that. But he wasn't--go ahead. He wasn't fully appreciated. He resented the fact that in his lifetime, his ideas were seen as quackery. Moises Velasquez-Manoff: Absolutely. Russ Roberts: I don't know if that, literally-- Moises Velasquez-Manoff: An insane asylum. Russ Roberts: I don't know if that literally drove him crazy or not. I wonder if-- Moises Velasquez-Manoff: I think probably syphilis drove him crazy. But that was the big--it is a huge tangent. But, the idea being that you can be right and never be recognized for it and in fact be sort of marginalized, easily, in your lifetime. Russ Roberts: Well, Milton Friedman stayed happy and cheery even when he was in total intellectual desert and laughed at because he thought that inflation was caused by printing money. So, he's always my exemplar of the other part-- Moises Velasquez-Manoff: Well, there you go-- Russ Roberts: But, plenty of people do, at least become bitter and deeply troubled by the fact that the world doesn't recognize them for their genius. And, he was--I don't know if he was a genius or just lucky, but he was right. We know that now as much as we know anything. And it must have been no fun to think that people were dying because people didn't accept his ideas. Moises Velasquez-Manoff: Yeah. And in this case, and in the farmers' case--so, I mean, they don't care if other farmers accept it. Because they are making a profit. They are [?] as they did before. And they also--truth be told, so the guy I profiled in Kansas, Daron Williams[?], they are also selling to these niche markets where they can get slightly more money for their product. Because they can say, you know, 'This is cows, raised in such-and-such fashion.' Russ Roberts: Correct. Moises Velasquez-Manoff: But, not all of them are. There is a guy, Dave Brandt, out in, I want to say, I think he's in Ohio. He's using cover crops--no animals. He's competing directly in the commodities market. And he's getting--he says, 'Yeah, I produce stuff about 20% cheaper than all my neighbors. So, it's not--it's not absolutely true that, like--for example, if we think of that, if we could scale all this up, will that little advantage of having that niche market would go away. Right? Because there would be no niche market any more. But this guy is competing in a huge market already; and he's doing fine. So, I don't know. So, I mean--

41:49 Russ Roberts: So, I guess, just to bring in a little more economics--and I think you alluded to this in a phrase, maybe a sentence in your piece. But, if everyone did it, and it brought down the cost of production enough that it lowered price, through competition, people would eat more of some of this stuff. And that might offset some of the gains, because there would be more land, then, devoted to some of these products. And so--the world's a complicated place. Moises Velasquez-Manoff: It is complicated. But, I think that what is indisputable, or at least somewhat indisputable, is that-- Russ Roberts: Oxymoron of all time, Moises--I love that-- Moises Velasquez-Manoff: Right, is there a softer adjective for 'indisputable?' Russ Roberts: It's like somewhat literal. Is it figurative, or is it literal? Moises Velasquez-Manoff: Yeah. These guys, their land is more resilient when they farm it this way. So, they are more--they are better able to withstand the inevitable shocks of farming life, like not enough rain. For example, if you have more carbon in the soil your crops are more resilient because there is more water stored in the soil. Not having to use as much fertilizer because you have more carbon in the soil. So, there's a way that it improves farming such that, you know, they are constant sort of shocks from price to weather to what have you in farming that you are insulated a little bit from those shocks because your soil is healthier. And I that is something that everyone could get on board with, in theory. The flip side, though, is this psychological aspect of tradition that we talked about. And I have to say that the one practice that people have the hardest time--and I do, too, in some ways--considering that it might have been a mistake, is plowing. So, these guys are all doing no-till growing, which means they don't plow any more. Because plowing causes carbon soil loss. So, it's like 10,000 years of agriculture [?]-- Russ Roberts: Human history-- Moises Velasquez-Manoff: right? And all of a sudden, it's been a mistake? Russ Roberts: Yeah; we call it 'working the land.' You tell me I'm not supposed to work the land any more? It's--yeah. That's kind of weird. Moises Velasquez-Manoff: Well, the reason it is, is because we plow because it sort of loosens up the soil, obviously. And you can use cover crops also to loosen up the soil. Like, these guys all grow these huge daikon radishes that are like--feet long. If you look at photos of what David Brandt grows, they're like 2 feet long, these radishes. And they break up the soil--these huge roots going into the soil break it up. That's number one. And number two is, you plow to limit weed growth. And, what these guys use instead is--First of all they graze their land; they rotate grazing into their land. And they use carbon crops to basically--what they are doing is engineering an ecosystem, where weeds can't get a foothold. So, when you grow crops there that grow really high, you are squeezing out the weeds. You are not allowing the weeds to take root. Russ Roberts: It's just so incredible. Yeah. There's something really beautiful about it, right? And I love the inevitable trial-and-error: they are trying different things. Like, I'm sure the first guy trying this didn't say, 'Daikon radish. Of course.' You know, somebody thought of that idea and tried it, and it seems to work; and it's a beautiful thing. Moises Velasquez-Manoff: Well, you know, Gabe Brown pioneered a lot of this. He's in North Dakota, in the 1990s--incidentally, because he had--his crop had been ruined by hail for three years in a row, and banks would no longer lend to him. And so, he had no way to get to pay for things he needed to pay for conventional farming. So, he said, 'Well, how am I going to farm?' And then he thought, 'Well, how did the guys used to farm before they had synthetic pesticides and all this other stuff?' And he ended up reading the journals of Thomas Jefferson, who, you know, ran, like a-- Russ Roberts: a farm-- Moises Velasquez-Manoff: Yeah. Not just a farm--a plantation. Right? So, he read, and there he learned about crop rotation and using livestock. And you know, they had all this stuff figured out. And I think maybe even some of the carbon crops[?], at least the rotation of part of the carbon crops[?]. And then he also read about how Native Americans used to farm on the Great Plains. And, there he learned about legumes and mixing crops together. Legumes and corn. You know--the legumes get the nitrogen into the ground. And they provide, like, a way--the corn provides a way for the legumes to climb up. And the sort of idea that you are really creating an ecosystem more than just growing a mono-crop. Which you then harvest.

46:34 Russ Roberts: So, what's the potential for those? Is it going to make a difference, or is it just a cool thing for a few farmers? Moises Velasquez-Manoff: Well, the farmers--these guys are already running with it. We'll see how--I mean, that's sort of happening on its own. How we're going to yoke all of this to deal with climate change is, I think, a bigger question. I think we need some incentivizing to happen. That is--and there are some really interesting ideas out there. Like, so basically what you want to do is to incentivize farmers to treat their land a little bit differently so that they can get paid for carbon that's stored in the soil. So, obviously that's not going to happen under the current, the Trump, regime. Right? Because they don't believe climate change is real, or at least that's what they say. But, there is this--let's just assume that we come to our senses regarding climate at some point. And, again, this is an idea that is not only good for climate, it is good for agricultural land. Right? And we are--I spoke to some people who said, 'We are facing this much bigger problem: We basically don't have any more agricultural land. But we need to start, we need to feed a lot more people.' So, it needs to be more productive than it is. Now, you could say, 'Well, yeah, let's stop giving, you know, all our spare corn to--to the animals'-- Russ Roberts: Yeeah. We've got so many other problems. We've got so many problems in the agricultural area. I mean, we've artificially privileged corn, for starters. We pay people way too much money to do something that comes naturally--which is growing food for people in the name of "food security," which I think is just a cover for giving money to your friends. So, there are a lot of things we can do to fix agriculture. But, whether agriculture could be part of a climate-change solution, if things get bad, I think is definitely important. Worth considering. Moises Velasquez-Manoff: Yeah, but I--I think you are not going to get farmers on board talking about climate. Russ Roberts: Nope. Right. Correct. Moises Velasquez-Manoff: Half of them don't believe it's even real. I could mean that--I don't know that for a fact. But, for example,-- Russ Roberts: "Survey says...."-- Moises Velasquez-Manoff: Just talking to the farmers that I talk to who are doing it for regenerative agriculture, they are like, 'Climate change? Whatever.' You know, 'I just have to make sure that I manage [?]' Russ Roberts: They are just trying to do their job. They are not so interested in public policy. I get it. I am sympathetic to that. Moises Velasquez-Manoff: No, they--it's more than that. It's that they don't believe it's real because they read state people. Russ Roberts: Yeah-- Moises Velasquez-Manoff: They get that media. Russ Roberts: Well, I'm a little bit of a skeptic, too. I'm agnostic. I don't think it's false. I don't think it's fake. I think it's true that there has been some warming. We don't know how much. It's troublesome that it hasn't gone up a lot over the last 20 years--the temperature hasn't in the face of an enormous amount of extra carbon. Which suggests we don't fully understand the mechanisms. But, as I said--I think we should be cautious about it. But, for whatever reasons--not everybody agrees--and, it's--then you get the question: You're going to make them do something they wouldn't actually want to do. So that's going to be a lot harder. Moises Velasquez-Manoff: Well, yeah, first of all, you--I think the evidence is much stronger than you alluded to, that climate change is real and caused by humans. But, that's a whole different show, and many other shows. Russ Roberts: Yes it is. Correct. Moises Velasquez-Manoff: So, how are you going to get farmers on board, getting carbon into the ground? Well, you incentivize it through several possibilities. One is, in California, we have this Healthy Soils Initiative, where they are helping fund some of this stuff, because it often costs, you know, changing the way of doing stuff costs money up front. So that taking money from the State's carbon mitigation funds--so, California has got this ambitious plan to reduce our carbon emissions by, you know--the number actually I think is by 80% by 2050 or something like that, even though that isn't fact checked. Russ Roberts: If you keep raising the income tax, you'll do it easily. Because enough people will want to leave--move to other states--that you'll have fewer cars. Nah; I'm just giving you a hard time. I'm sorry. But I do think, to be serious for a second: I think the environmental movement as well as legislators need to think long and hard about how we spend our money to make the world a cleaner place. And, spending it wisely is always a good idea. No matter what you agree. No matter what the dispute. And, it's probably--right now, many things have been subsidized that are either not good or don't help or are actually counterproductive. So, it would be good to spend some money--that we already are allocating. Maybe move it away from some things and toward other things. Moises Velasquez-Manoff: For soil, here, there's now some money available to people who want to try to get carbon in the ground. And so, actually, this has been promoted. The carbon farming idea has been promoted--just as good agricultural practice--by a Department in the USDA [U.S. Department of Agriculture]--already. The Resources Conservation Service. Which is--this is a little-known-about--sorry, the NRCS, National Resource Conservation Service--that was founded in the wake of the Dust Bowl. Which, of course, is this huge agricultural-- Russ Roberts: dramatic [?traumatic?]-- Moises Velasquez-Manoff: dramatic experience that happened that we forget about. But basically we plowed the hell out of land that shouldn't have been plowed. And then, in conjunction with some dry years and a lot of wind, the topsoil--like, the entire upper Great Plains ended up blowing away. And if you read about what was happening at the time, like, the sky was red as far away as Washington, D.C. I mean, it was like a huge environmental catastrophe. And it was driven by farming. So, they founded this organization--it wasn't called the NRCS then, but it is now. And they focus on soil health, and in recent years they've been trying to promote soil carbon. And they have like 35 practices, 30-some practices that they consider that sort of build--that deal with this problem of, if you plow your land, you are going to have a lot of the carbon blowing away, or just eroding away, from water. So, they help also fund some of these things, already. Very tiny amounts of money. Not huge amounts of money. And the idea is they are funding you to take care of agricultural land, which in a way is sort of, even though people own it, is also a resource in common for the country. Russ Roberts: Well, it has external--how you use it can affect some people other than yourself. Obviously, when you own your own land, you have an incentive to not graze it to the ground; not take out all the nutrients. You may make mistakes--out of ignorance, or tradition, or other reasons. Russ Roberts: But, the other thought I had was--you mention niche markets. It would be an interesting challenge for a foundation to help to fund farmers to try experiments on their own land, who would then in turn could market their products as being more environmentally friendly, and use some kind of labeling to encourage customers to pay a premium; or maybe they wouldn't have to, because it's as you say, maybe it pays for itself. Moises Velasquez-Manoff: Yeah. I think it pays for itself. You know, there's an initial period of years where it's not paying for itself. Russ Roberts: Sure. Moises Velasquez-Manoff: But then, over time, as the soil gets healthier, it starts paying for itself. And you end up producing your crops for less investment per bushel than your neighbors. And so, one really interesting idea that is out there, and I actually did not talk about this in the article, is to give people who are building soil carbon--give farmers who are building soil carbon--a discount on crop insurance. Russ Roberts: That's cool. Moises Velasquez-Manoff: Because, in theory, their farms are more resilient. Russ Roberts: Yep. Should happen naturally. Moises Velasquez-Manoff: Well, crop insurance, as you know as an economist--it's a complicated--there's a complicated set of calculations that go to dictating what your premium is for the insurance. Russ Roberts: Well, I don't know anything about it--as an economist. Or as a farmer. Moises Velasquez-Manoff: But, you understand it [?] Russ Roberts: Sure. It's risk. Insurance, I know a little bit about. Moises Velasquez-Manoff: Right? So, in theory, your risk is lower [?] building [?]? You actually [?] lower premiums. So, there's one incentive right there. We use also, in New York, they are thinking about giving people, farmers who build soil carbon, tax breaks in some way or another--I don't know if they are calling them 'tax breaks.' They have another term for it. But, anyway, there are multiple ways of doing this, of helping out farmers who are doing this, besides just handing them cash--I guess is the idea. Some of them are--legislators around the country are very interested in this because they are very interested in agriculture. And some of them are also interested in climate-- Russ Roberts: It's a fascinating--go ahead. Sorry. Moises Velasquez-Manoff: We have this healthy soils initiative: it's sort of like the example in the country of how this can be, how it can be incentivized; and they are getting some state funds to do some of this; our farmers get some state funds to do some of this stuff. Russ Roberts: The other thing I was going to say is that, you know, farmers--we spend a lot of time eating, as human beings. And, as Americans, we eat a lot--mostly--for many of us, too much. And it's just interesting how few people are involved in agriculture. I often point this out: it's 2 to 3% of the American people are in farming: because it's so productive we don't need a big population in farming, industry, in terms of labor. And, not only is it efficient enough that we only need a few: we make so much food that we can export a bunch of it. And so, it's a very small group of people that we are talking about, to change their habits, if indeed this is a useful and productive thing to do.

56:22 Russ Roberts: But, I want to change--we're almost out of time, and I want to talk for a bit about the human microbiome--the small part of us. And I want to turn toward your book, An Epidemic of Absence. And that book had an incredibly provocative idea, which, again, was an amazing example for me of unintended consequences, complexity, and emergent order. This idea that by cleaning up our environment and taking worms and parasites and germs--basically, making our environment as sterile as possible--and I just talked to Janet Golden about the evolution of how we treat babies, here on the program, in the 20th century and what a great triumph that was--that we took so many things that killed people and got it out. We learned that milk could spoil and we learned that germs carry disease and we learned that there are all kinds of things that people shouldn't eat and should be near each other at certain times. And that was a great triumph of civilization. It lowered infant mortality in extraordinary ways over the first half of the 20th century. Lots of other things along the way, of course--not just our scientific knowledge. But, you point out that maybe that came at a cost. Certainly it came at a cost. Maybe that cost was very large for certain people, whose bodies, without the germs to fight, started fighting themselves. The autoimmune system started to eat us, instead of the germs that were no longer there. They had to have something to do. And I found that deeply provocative. The book came out in 2012; we talked about it in 2014. And, 6 years have passed since you published the book; and more than that has passed in some of the research. And, it's an idea that's deeply appealing--to the point where you, yourself, actually put worms into yourself, deliberately. And other people continue to do that, to fight certain autoimmune disorders. Do we have any more knowledge about whether this is just a possibility? true? maybe? What's happened? Moises Velasquez-Manoff: Well, I think the hygiene hypothesis has only gained more steam and more evidence in its favor. But, it's often, like: It depends who you ask, the meaning of what the hygiene hypothesis is, changes depending on who you are talking to. But, the idea that we need to tune our immune system early in life: that it needs to be educated early in life--I think we are just getting more and more evidence that this is true. And educated by the right set of microbes. And they are not just microbes that we are fighting against. Many of them are just commensal microbes that, because of the way we live now, and because of what, of dietary changes, for example, that we are selecting for different types of microbes that are not necessarily the ones that educate our immune systems in a way that prevents some of these diseases from arising. So, in terms of the microbiome front, that these are just the microbes and, you know, the unicellular organisms: there's so much research, it's hard to know what to look at. But, for example, I wrote an article about--a lot of this research started in Europe, with the farming stuff. So, it was: Farming kids were less allergic. Why? Because they are probably exposed to manure and cow sheds and they drink unpasteurized milk. So, then there is an interesting example--and I don't think this existed when we spoke last time--but, of Amish kids in the United States now. Where, these Amish kids, they actually come from the same part of the world--in Switzerland, German-speaking Switzerland, where a lot of this research first started. So it's an interesting comparison. Like, they are in theory comparing genetically similar people. So, what they, this most recent set of studies--of course, the Amish kids are like the least allergic of anyone they've ever seen in the developed world, of any subset of people. Russ Roberts: It just tells you [?] that that cell phones causes allergies. Moises Velasquez-Manoff: Well, yeah, it's funny. I visited one of these farms. And I was talking to, like, an Amish elder, and he was like, 'We can't deal with the cell phones.' Like, 'We've dealt with everything up until now. The kids are getting the cell phones and we can't stop them.' Russ Roberts: The ultimate parasite. Yeah. It gets hold of the human host and then they have their way. Moises Velasquez-Manoff: Yes. So like, that's a whole 'nother story. And also, it's just like a [?] idea: the Amish do get vaccinated[?]--I don't know; there's this idea that that they don't get vaccinated. They do. They get vaccinated. So it's not like they are not getting vaccinated. Russ Roberts: They are not against science. They are against technology of certain kinds, I think. They want to do certain things in traditional ways. Moises Velasquez-Manoff: Yeah. I mean, each sect differs. That's another thing that's not appreciated about the Amish: is that, they sort of decide in their communities what they are going to do. So each one--there are more strict ones and less strict ones. The one that I visited in Indiana: they got vaccinated. Like, they didn't want any external electrical lines coming to their houses. But they used lamps in their houses that had batteries. So, there you go. There's a paradox. One of them was a dairy farmer, and he had just upgraded to a modern dairy farming system because he was like, you know, he still plows his land with horses; but he, to be able to sell his milk into the market he has to pasteurize it and do all the stuff that modern dairy farming requires, so you can sell it. In any case, the guys, the kids were super non-allergic. And so they did this interesting study where they compared the Hutterites, which were another group that stemmed from the same area of the world. And they were sort of religious. And they destick[depict?] themselves--they live in the Upper Midwest and the Plains States of Canada--the plains, not the states, provinces of Canada. And they are as allergic as anyone else. Right? They are just as allergic as your average American, Canadian. Russ Roberts: Even though they are living this agricultural life that many might think is protecting them. Moises Velasquez-Manoff: Right. So, what's the major difference? Well, they keep their livestock far away. They do, like, this factory farming and they keep it far away from their homes. Whereas the Amish have these little farms where their homes are like 20, 30 feet from the barn. So, if you think of the cowshed as this factory of microbes that are, probiotic microbes that prevent allergy, they are missing all that in the Hutterite land. And they also--the men are the only people who work with the animals. So, what's interesting about the research from Europe is that they find that women who are pregnant who are working with animals have kids who are like the least allergic of all the women. It's like, the earlier your exposure begins, the less allergic you'll end up. And they think it actually--the microbes actually stimulate the mother's immune system. And that stimulation goes through the placenta--I mean, it, via, like Cytokines[?], which are these immune-signaling molecules. And starts training the infant immune system before they are even born. So, you get--so, this happens in Amish country, because pregnant women are out there milking the cows, too, and the kids are out there from an early age playing in the barn. They are getting this exposure. Whereas in Hutterite country, the kids don't have any of that exposure, and the pregnant women don't have any of the exposure. And, they did this really interesting study of the different immune profiles. And they have a different sort of--here are two populations that are genetically very close, because they come from the same part of German-speaking Switzerland; and southern Germany, I think; and they have this very different immune system. And they did these studies where--they tested in mice, and sure enough the mice were exposed to Amish cow dust, Amish cowshed dust, were less allergic than the mice that were exposed to Hutterite dust. So, I mean, like, this research is getting closer and closer to an actionable pro-biotic. Right? Based on, let's just say, an Amish cowshed pro-biotic. Where that, we would use as an intervention early in life. It's getting closer. We're still not there. Russ Roberts: Well, you just [?] your kid. Or, you could just, when you are pregnant, go milk some cows or when your kid's early on, go have him play in the cowshed, and breathe a lot and absorb it. We should build our own cowsheds! Every house should have a cowshed. Moises Velasquez-Manoff: That is going to be--it's going to be more complicated. Because it has to be chronic exposure. Russ Roberts: Oh, okay. Moises Velasquez-Manoff: So, taking your kid to a cowshed for a week-- Russ Roberts: not enough. But. But, while you are in the cowshed, you want to eat a peanut butter sandwich with your kid. Because that's another example where people are saying--this peanut allergy thing is because people are eating their peanut butter so late in life, they don't have a chance, right? Same argument, right? Moises Velasquez-Manoff: Well, yeah, in a way. Except for we're talking about exposing yourself to the allergen versus training your immune system-- Russ Roberts: Yeah. Okay. Different mechanisms. Fair enough. Moises Velasquez-Manoff: Different mechanisms. But you can do the peanut butter sandwich thing regardless of whether or not you are in a cowshed. Obviously. Russ Roberts: I just wanted to kill two birds with one--I don't know, peanut butter sandwich. One trip to Pennsylvania. Russ Roberts: Let's close with something you discuss in the--and we'll put a link up to your Amish article, which is really interesting, although it is a small sample, as you point out and that some people have pointed out may not be as reliable as we'd hope. But, it is very interesting. Moises Velasquez-Manoff: So, the Amish are a small sample. But, the other stuff, from Switzerland, those are thousands of kids at this point. Hundreds, at least. Thousands, probably, of kids they've done over and over and over in Europe, not just in Switzerland but also in Denmark, in parts of Germany. I mean like, everywhere. This is a very solid finding over there. Russ Roberts: That, exposure to agriculture reduces allergies? A correlation? Moises Velasquez-Manoff: To cowsheds, in particular. Russ Roberts: Okay. Moises Velasquez-Manoff: And to milk. I mean, it's very--it's a strong binding. Russ Roberts: Cool.