Timothy Searchinger: Biofuels vs Foods and Major Climate Change Policy Errors – #23

Steve and Corey talk to Tim Searchinger about the unintended consequences of biofuels policies.

Steve: Thanks for joining us. I’m Steve Hsu.

Corey: And I’m Corey Washington. And we’re your hosts for Manifold.Our guest today is Timothy Searchinger. Tim is a research scholar at the Woodrow Wilson School at Princeton University in the Science Technology and Environmental Policy program. Though trained as a lawyer, Tim’s work today encompasses ecology, agronomy, and economics, and analyzing the challenges of feeding a growing world population while reducing greenhouse gas emissions.He was lead author on a groundbreaking series of articles in Science magazine that offered the first calculations of greenhouse gas emissions associated with land use changes due to biofuels and the potential effects on food consumption. He’s also lead author of a series of reports for the World Resources Institute, the World Bank, and other organizations on how to meet global feed needs in 2050 while reducing greenhouse gas emissions.He works across the world and currently has projects in Rwanda, Colombia, Thailand, Vietnam, and Denmark, on evaluating the potential for livestock or crop improvements to reduce emissions and protect forest.Tim Searchinger, welcome to Manifold.

Tim: Happy to be here. Thank you for having me.

Corey: So Tim, you and I are old friends, and we hadn’t seen each other for quite a while. To be honest, how I came to bring you on the show today was, I was looking at The New York Times in November of last year, and there’s a huge story on the cover titled: “Palm Oil was Supposed to Help Save the Planet. Instead it Unleashed a Catastrophe” about the destruction of forests in Borneo as a result of changes in US biofuels policy.And in that article, you’re profiled as the person who probably before anybody else realized that this change was going to be a catastrophe. It’s a well-meaning change in policy that had unintended consequences. Can you tell us what’s happening in Borneo?

Tim: Well, Borneo is obviously a naturally highly forested place with very wet, very carbon dense and biologically diverse forest. And it is now being converted, has been heavily converted to oil palm production. It’s also been heavily deforested for timber purposes. A lot of it is for oil palm production. Oil palm has become the cheapest way of supplying the world’s growing demand for vegetable oil. And some of that vegetable oil is going to meet rising food request. When people go from eating $1 a day to $2 a day, the first thing they do to diversify their diets is eat more vegetable oil. But some of that vegetable oil is going to supply biodiesel, one of the big sources of biofuels.The basic story is the world’s increased demand for vegetable oil, including biodiesel, means you’ve got to produce it somewhere, and one of the big places to produce it is by converting tropical forest in Borneo. And that has huge implications: larger releases of carbon dioxide, the most potent greenhouse gas, very sharp biodiversity effects, and then a lot of effects on indigenous people who are living there.

Steve: Can I ask, the carbon release, is that from burning off the jungle?

Tim: Yeah. Basically, vegetation is 50% carbon, so when you see a tree what you’re looking at, 50% of the physical quality of the tree, the non-water part, is carbon. And then on top of that, soils store a huge amount of carbon, so soils and vegetation store four times as much carbon as there is in the atmosphere. About a third of the carbon in the atmosphere that’s been added by human beings has been through land-use change caused by primarily agricultural expansion over the last 150 years. So when you clear a forest, you put that carbon into the atmosphere.

Steve: And the crops that you’re growing then, in that agricultural land, those crops are fixing carbon from the air in order to grow, but then I guess eventually you may burn them, so that carbon gets back into the atmosphere?

Tim: Yeah. The typical crop of course is only growing a little bit each year and you plow it up. The carbon that is absorbed by the crops, we eat it. So actually every time we breathe, we’re breathing out carbon dioxide that was actually fixed by a crop. So some of the carbon dioxide is going to feed people.In oil palm, there is a tree that’s created, and that stores some carbon. And then the oil palm of course is also heavily carbon. Now the benefit of using vegetable oils for fuel is that you displace fossil carbon, you displace diesel or gasoline, and that gives you a greenhouse gas benefit. But the cost is that you’ve lost all of this carbon that would be stored there otherwise.One way of thinking about biofuels is, the benefit is displaced in fossil fuels, but the cost is whatever you’re not producing on that land as a result. And the historic error with biofuels was that people basically treated land as free. They didn’t count any cost to the loss of the carbon that would otherwise be on that land, including the carbon that would be being produced and being consumed by people.Over a really long period of time, you can get a greenhouse gas benefit from using biofuels. But for decades you’re going to increase carbon in the atmosphere due to the loss of the native vegetation.

Corey: What was the policy change in the US that led to this deforestation in Borneo?

Tim: Yeah, so the big … And by the way, that’s not all due to US biofuel policy. First of all, we have growing world demand for vegetable oil. And then on top of that, Europe has had a large increase in biofuels too. Most of Europe’s is due to biodiesel, whereas in the US we are primarily using ethanol from corn, which causes other problems but less problems than you have in Borneo.Borneo has been… Essentially what happened is that the world figured out how to produce vegetable oil at a high yield from oil palm, and that made that a good place to produce it. The policy change in the US was mainly in December of 2007, when Congress adopted a huge increase in the biofuel mandate. We’d been subsidizing biofuels for quite a while, but there was a multifold increase in the biofuel mandate, which basically requires that increasing percentages of our transportation fuel be co-blended with some kind of biofuel, eventually up to about 14%, and biodiesel is one of those fuels. In fact, it has a kind of preference in particular.

Steve: But do you have a breakdown? So for a particular hectare in Borneo that they burned off the jungle in order to start growing stuff there, how much of that demand is response to US biofuel policy versus people going from $1 a day to $2 a day and needing some cooking oil?

Tim: Probably actually a minority of the total amount of deforestation is due to the US biofuel policy. Nobody really knows the exact percentages because these things all get blended in one place or another. One of the questions is, would the world have been better able to meet the demand for vegetable oil without also the increased demand for biodiesel. So there’s certainly a significant amount of increased deforestation, but nobody really knows.And for Borneo per se, Europe has probably been a bigger driver because they’re even more into biodiesel than in the US. However, probably Europe wouldn’t have adopted this biofuel mandate if the US hadn’t been going for it.

Steve: But the non-biofuel part of it goes back to what Bernie said the other day, which was that population increases in the third world are leading to a huge environmental or carbon impact.

Tim: Yeah, exactly. So our population has been growing a lot. Right now we’re about 7.5 billion. We’re going to go to about 10 billion by 2050. So you have to provide that food. Then on top of that, you have decreasing numbers of just horribly poor people, or at least decreasing percentages. As I said, when people are able to eat just a little bit better, one of the first things they do is they try to fry their food or do something to increase the tastiness of it. And vegetable oil is one of the things we use, so there’s been a particularly large increase in demand for vegetable oil. So the combination of those two drives the demand for vegetable oil. In the US, we never think about it, right? I mean, you think about frying, but you don’t think about the price of vegetable oil or whatever. You have no idea if increased demand has greatly increased the price.

Steve: I seem to recall that in some relatively poor countries like Indonesia or places like that, if the government raises the price of cooking oil, that riots ensue. So I guess that’s very important to their level of wellbeing.

Tim: Exactly, exactly right. So I don’t think we are increasing significantly the consumer demand for vegetable oil per person, but we are doing it through biodiesel.

Corey: One of the general ideas that comes through in your work is that there are trade-offs, and that land use is effectively a zero sum game. You could use land for growing food, for livestock, you can use it for wood pulp, timber. But you increase one at the expense of decreasing the others.

Tim: I think that’s mostly accurate. The real issue is that people who have looked at these changes count the benefit of what they’re going to be producing and not the cost. And so it might get better. The basic way to think of it is this. We need more food, about 50% more food by 2050, and we need more carbon storage. Almost every strategy for solving climate change assumes we’re actually going to increase the amount of carbon stored in vegetation and soils. But given that fact, we also have a fixed amount of land. We’re not making any more land. So the only possible way to do that is to increase the efficiency of using land.What that means is, if you have land that’s really good at growing forest and would be bad at producing corn, you want it growing forest. But vice versa, if it’s really good at producing corn and would be bad at producing forest, you want it producing corn. So it is possible that when you change the use from one to another, you’re able to increase the total benefits, the total output. But just changing one form to another by itself doesn’t actually do that. In the case of biofuels, if you stop using land for food and you start using it for energy, you get a benefit in terms of displaced fossil fuels. But the bottom line is you’ve increased the demand on the world’s land, so there’s going to be a cost.And we can go into it, but the fundamental error that was made in bioenergy was the belief that land was free. And the typical analysis that assumes that bioenergy is good for the planet, would be identical if you assumed that literally land was created to grow the biofuel production. You increase demand for biofuels in the US, and instead of using Iowa or Michigan corn land or soybean land, instead of doing that, you actually cause land to emerge out of the Pacific and grow it there. That would actually have the exact same calculation, according to the people who are generating estimates of benefits from biofuels, as using the best land in Iowa or Michigan.Obviously there’s a difference. One is it has a big cost because you’re not producing food, and one is you get additional land. So the basic issue is land has a cost. It has an opportunity cost. Use it one way, the cost is not using it for another. And the simple, simple point is you have to count that opportunity cost.

Corey: The arguments that people pro biofuels are going to give… I want to try an argument on you. I think it’s going to bring up some points you just made, but here’s the argument. Biofuels are key to a clean energy future. Unlike fossil fuels, they offer zero net carbon emissions opportunity for creating energy. When you grow biofuels, plants suck carbon out of the atmosphere. When you burn biofuel plants, some of that carbon gets back into the atmosphere, so it’s a zero net emissions. Repeat the cycle, you always end up with a net zero carbon emissions. What’s wrong with that argument?

Tim: Yeah, well there are a few ways of saying what’s wrong with that argument. One is what I just said, that it assumes the cost of using land is zero. It says, look, to grow those plants you need an acre of land. And where in that analysis are they counting the cost of that land? That land, if you’re not using it for biofuels, could either be a forest or storing carbon in some way. Or it could be producing food, and if you produce the food there, you increase the capacity to have forest storing carbon somewhere else. So one way of saying it is, that analysis treats land as free.But there’s another way of thinking about it as a kind of pure math error. Basically, when you burn biofuel you’re emitting carbon. I mean, what literally comes out of the tailpipe of the car is carbon. And in fact for the case of ethanol, you’re going to emit overall about one and a half times as much carbon as when you have gasoline, because the amount that comes out the tailpipe is the same, but actually there’s another 50% that goes off when you ferment starch into ethanol. So when we turn that corn into ethanol, you actually have more carbon being emitted. The theory is that that carbon is offset by the growth of the plant, so bioenergy, if it’s going to work at all, works as an offset.Now let me give you an example where that would be true. Imagine for some reason or other you have a bare acre of land and it’s going to remain bare. Somebody just likes to go out and plow and grow nothing for some reason or other. And now you’re going to say, “No, no, instead of doing nothing with it, we’re going to grow plants and turn them into a biofuel.” Now those plants absorb additional carbon, and then that carbon, that additional plant growth offsets the carbon emitted by burning the biofuel.But the key requirement for any offset is [that] something be additional. So if you have an employee and that employee works overtime and you say, “I’m going to offset your overtime with vacation time,” you can’t say, “Well, here, I’m going to offset it by letting you take the vacation time you’ve already earned.” [laughs] You have to give them additional vacation time. So if you want plant growth to offset the carbon emitted by burning it, you have to have additional plant growth. In the example I gave there was additional plant growth.But what happens if you’re just taking a corn field that was already producing corn? It was already absorbing carbon from the atmosphere. And just diverting that to biofuels doesn’t offset anything, because it doesn’t create any additional plant growth. What it does do is simply divert plants that are going into food, into biofuels, and then you’ve got to replace the plant somewhere else. So that’s the difference. The basic error was this belief that all plants are free and an offset. But when you use plants for one purpose, you’re not using them for another. And only additional plant growth actually constitutes an offset.

Corey: You’re convinced Steve?

Steve: Well, I think it’s obvious that you want to have as much biomass as possible because it’s mostly carbon. And so to the extent that you’re growing stuff on the land, that’s great because you’ve sequestered some carbon there for free. But if you chop it down and burn it, and the average amount of biomass on that land over the course of the next year is reduced, I see the point. I mean, you’re not actually sequestering as much carbon there as you could be.If we allowed you to grow the biggest, the most massive trees possible on that land, that’s probably the best possible use of that land to sequester carbon, right? And then if I built little greenhouses on top and grew my biofuel stuff up top, then I guess we’d be okay, right? Then I’d be using land productively both to sequester carbon and to produce some stuff to run my car or cook my vegetables in. But that’s not apparently what people are doing. And to clear the land in the first place, they’re burning down some beautiful jungle that was sequestering tons of carbon.

Tim: And if you’re producing food, that food absorbs carbon. And the question is, why don’t we think that growing food is good for the climate? Why isn’t that a carbon sequestration strategy? Well, the only reason it isn’t is that we actually eat that food, and then we emit the carbon.

Steve: Yeah, if we grew the food and we just left it lying around, so it was not floating in the atmosphere absorbing photons, that would be fine. But what we actually do is we eat it, and eventually it gets back into the atmosphere potentially. I don’t know if—

Tim: Exactly. But the point is, we can actually solve climate change to some extent if everyone stops eating. Nobody tends to offer to do that. We make this as a joke, but there are actually … I had a paper in Science in 2015 where I showed that the calculations that the federal government does to find some greenhouse gas benefits from ethanol literally count the fact, they estimate in an economic model, that much of the food diverted to biofuels is not replaced. As a result people eat less, as a result people breathe out less carbon dioxide, and the greenhouse gas benefit from people breathing out less carbon dioxide is the benefit that they attribute to ethanol.Unfortunately, the people who eat less when we divert plants to ethanol, are not me. You can’t see me, I’m a little overweight. The world would be better off if as a result I ate less. But actually the people who respond to higher prices are the world’s poorest people.

Corey: Steve’s gone keto and he claims he’s eating less as a result.

Steve: Yeah, I’m very green from keto. No, I mean, if you compete in the marketplace for carbon, pricing out poor people so that they literally starve and die so that I can drive my SUV, that is very green, right? I’ve helped the environment.

Tim: It’s a great greenhouse gas strategy, but you don’t care about people at all.

Steve: Right. I mean, it’s very similar to what Bernie was saying, which is that the fewer people, the better off the environment, right? Growing up in the ’70s, we took this very seriously. I remember overpopulation being a huge thing. We would discuss it in school, and it would be part of our social studies learning or even science learning class where we would say, “Yeah, overpopulation is one of the biggest problems facing humanity.” And it’s kind of obvious that if each of us has a non-zero carbon footprint, which is inevitable, having more people is just bad for global warming.

Tim: But of course there are different ways to deal with the population. So the good way to deal with population growth is to educate girls and lower mortality rates for children, and as a result people decide to have fewer babies. That’s happening in most of the world, and that’s the good way. The bad way to do it is to make food prices really high [so] that they die. Now in the real world, of course, very few adults actually die because of reduced food consumption. Actually some children die because of insufficiency. In that regard, you’re right, maybe there is a greenhouse gas benefit to increased child mortality.

Steve: Yeah, if you were a crazy right-wing economist you might say “Oh, the incentives: if I make food really expensive, the incentive is to have” — maybe, I’m not sure this is really true, but — “is to have a smaller family, and it does curb population growth,” or something, I don’t know, but …

Tim: [laughs] Yeah. Hopefully no one’s actually saying that. The interesting thing, of course, is that actually higher child mortality tends to lead to higher population growth, because people overcompensate by having more children.The good news is that one of the best things you can do to reduce climate change is literally keep children alive and educate girls and provide access to family planning to the people in Africa, who are the only people who are still having large numbers of children.

Steve: But if I’m not misremembering, it’s the access to family planning part that got Bernie in trouble. Does anybody remember what he actually said?

Corey: I don’t remember the context of the claim. Was this the speech he gave recently?

Steve: I don’t know if it was a speech or some, just public interaction. He basically said like, “If you want to save the environment, you need to limit the population.” I think he might have used the word abortion. I don’t remember. But I just saw it. You know how you see these outrage things on your Twitter feed, like, “Oh, Bernie said this.” But the basic point that limiting human population is good for the environment, I think that’s true. How he said it, I don’t necessarily endorse.

Tim: The good news is that almost everywhere in the world people have reduced their fertility rates to replacement levels or below. We’re going to continue to have population growth in Asia due to the fact that that happened only too recently, and as the children who were born in the last few decades age, their population will grow.But the one place in the world that still has a lot more than replacement-level children is in Sub-Saharan Africa, basically because that’s the place in the world where we still have very high infant mortality and where we don’t educate girls in high school. By doing those two things in pretty much every culture in the world, people voluntarily reduce their fertility rates. So there is a kind of a win-win for humanity there.

Corey: I was just in Nigeria actually, in cities importantly, and I was talking to some of my colleagues there, and they point out there’s a pretty substantial difference between urban areas and rural areas there. People in urban areas now are having three, maybe four kids, which is a significant reduction, but in the rural areas it was still on the order of seven or eight kids. I think Niger right now has the highest birthrate in the world, and it’s on the average of nine kids per female.

Steve: So having never been to Africa but having looked at these numbers, it’s hard for me not to predict real crises and disaster in the next few decades for Africa, because how are these people going to feed themselves? It just seems like the population growth is outpacing economic growth in a lot of these places. So the per capita GDP, I wonder if it’s going up. It may be going down.

Corey: I asked that question when I was there, what the growth rate was, and I think I didn’t get a straight answer because the people didn’t trust the numbers out of the government, but it’s supposed to be in order of a couple percentage points definitely below population growth.

Steve: Even though for the upper class in India — and maybe middle class, depending how you define it — there’s been successful economic development, I think if you look at the numbers of the people who were closer to the bottom — and by bottom I mean maybe bottom 25% of the Indian population — I think things have not been getting better. Like if you look at malnutrition numbers. So it’s pretty scary.

Tim: Yeah. Actually, Africa went through a period of significant economic growth for a while, and then it kind of became a question of what’s going on there and it tapered off a little bit. There are I think real opportunities there, but there’s no question that the extremely high rate of population growth is a huge problem.The good news is that when countries do reduce their populations, they tend to get an economic dividend, because [when] you find yourself with a larger percentage of the population in the productive years, you have fewer people that you have to care for who are too young to work or too old to work, at least at that time. So you get these big economic dividends, and hopefully by the time that that population ages, you’ve had this huge amount of economic growth in between. This is an opportunity.And the other thing is that even the poorest countries in the world that have actually gone to the effort to educate their girls, have pretty much all had huge reductions in fertility rates. The urban population growth helps too. But this is just one of the many issues.

Corey: I want to get into a topic you discuss in some of your articles, which is the calorie gap. Let me know if I get this right. You say between 2006 and 2050 there’s a calorie gap of approximately 6500 trillion kilocalories per year. We need about 70% increase in available food in those 44 years.

Steve: Can we define what you mean by gap?

Corey: Let’s let Tim define it.

Tim: Yeah — by the way, we updated. That’s an older paper. We now have a new one where we focus on 2010 to 2050, where the calorie gap is 56%. And what this is, the gap is the number of calories produced in 2010 globally by the world’s farmers made available, let’s put it that way, and the number of calories that are going to be needed to feed the world in 2050 under business as usual if trends continue along the projected lines. That means in 2050 the world’s farmers would need to produce 56% more food.

Steve: So you did the calories per capita in 2010, and you want to maintain that?

Tim: Yeah. Actually, we did more than maintain calories in 2010. We somewhat improved them as the world’s poorer people get wealthier. In fact, we added just a small amount, which would be the amount that would be needed to make sure that nobody is hungry.

Steve: Okay. So you have a basic requirement level of, I don’t know, is it like 2000 calories or 1500 calories per day per person, or…

Tim: Yeah, it’s usually like 2200, but actually the food available, meaning the food that is in theory available to consume, needs to be around 3000 calories because there’s a lot of waste.

Steve: Okay. And so the gap is relative to that.

Corey: And you’re building in some economic growth because you’re assuming people start consuming meats?

Tim: Yeah, we have an increased consumption of meat, and that’s based on the FAO, the Food and Agricultural Organization’s projected diets. It could actually be much larger than that. They were relatively conservative because even in 2010, 60% of the world’s 10 billion people still didn’t consume very much meat or milk — more, but not that much. So even if in that scenario you have to produce basically more or less 50% more food per year, and then the question is, how do you do that? Part of the challenge is that — and this again comes back to the biofuels — almost everyone who looks at that, even without biofuels, predicts that we’re going to have to clear more land, because we have to increase yields at a higher rate than our historic rate.Almost every climate strategy requires that we actually reduce the amount of agricultural land, so whether you then add a biofuel demand on top of that, it’s potentially completely disqualifying. Let me give you a couple of ideas about that. It’s not just liquid biofuels. It’s also just cutting down trees and bringing them to power plants that are people talking about, or fast growing trees and things like that. A lot of people say, “Look, we need to get 20% of the world’s energy from bioenergy in 2050.” You say, “Okay, what percentage of the world’s harvested plants today would that require?” We harvest plants for crops, we harvest wood, we have grass eaten by livestock, and we harvest a fair amount of crop residues. So of all those that we harvest today, how much of that would have to be used to produce 20% of the world’s energy in 2050? And the answer is all of it. 100% of all of our harvested biomass is just enough energy to produce maybe 20% of the energy demand in 2050.So you immediately should realize if somebody’s telling you that that’s a good idea, when on top of it the fact is that we already need to produce 50% more of just about all plant material to meet growing needs, and we need to do it without clearing more land, you could probably understand that somebody must’ve made a big mistake. [Steve laughs] And the mistake was that they basically treated land as a free. They always double-count land. So on these projections they’re basically saying, “Hey, I can use that hectare of land, that acre of land both for food and for biofuels.” They just don’t deal with the fixed land budget.Let me give you one reason, one intuitive reason to understand this. People have this belief that something that’s renewable is free. I have a tree: I cut it down, I burn it, the tree re-grows. I could burn my tree and have it too. So what’s wrong with that thing? Why isn’t that free? Well, think of something else that’s renewable, which is your paycheck. You’re academics, you’re making the big money, so I say to you, “Hey Steve, give me your paycheck. It’s not going to cost you anything. You’re going to get another paycheck next month. It’s renewable.”But you’re a smart guy, and you realize if you give me your paycheck, you can’t use it for food, you can’t use it for rent, you can’t put some in the bank. The cost of giving me your paycheck is not using it for these other purposes. Well, that’s exactly the same truth for plant growth. If you use plant growth for energy, you’re not using it for food and wood products and carbon storage. If you want to be richer, you’ve got to get a bigger paycheck. You don’t just divert your existing paycheck to something else. And that’s basically the error that was made with bioenergy.

Steve: I’m reminded of the prophetic science fiction movie “Soylent Green.” Does everybody remember “Soylent Green” with Charlton Heston?

Tim: I’ve never seen it.

Steve: Oh, you’ve got to watch it.

Tim: I know, I know.

Steve: In the movie “Soylent Green” the whole world except for very, very rich people is reduced to eating these soylent crackers that the government produces. I think originally they wanted them to be made of soy and lentils, which is why they were called soylent, but I think in the movie they actually say they’re made of algae, which is growing in the sea. And that is a kind of a new, free source of land, right? You grow the calories in the ocean. But we all know what soylent green ends up being. It’s actually made of recycled people. That’s the big reveal. Oh, I’m sorry if I spoiled it for you.But the issue there was, of course, the free land was you start farming, you start growing algae in the oceans, and then that’s the way you get the calories you need.

Tim: Well actually, algae could be one of the ways that we meet some food needs. And growing in the ocean is difficult because of lots of practical reasons. Growing on land still takes a fair amount of land and water, but it’s more efficient than other things. But one day maybe algae could be a good source of animal feed, and it’s also potentially a source of fish-oil quality oil that you could use. So there could be some values, but it’s not going to feed … It’s still going to be small. [laughs]

Corey: Of course, you can’t predict technological change. Often we think there are insurmountable problems, and then there’s some disruptive technology that arises. We now have very effective and radically powerful tools for genetic engineering, and it seems quite possible that over the next 50 years or so these tools will allow us to develop plants that are, say, 500 times more effective at producing calories for human beings than existing plants. We may also be able to engineer algae of a certain kind that could provide food for people. So aren’t you assuming that there’s no disruptive technological change in your calculations?

Tim: Well, in a way we’re kind of relying on some disruptive technological change, because when we try to come up with solutions, you have to increase yields at a faster than historical rate. Historically, a lot of those yield gains came from just adding synthetic fertilizer, from doubling irrigation area, and those really aren’t doable anymore for environmental reasons and just fundamental limitations. We already used the fertilizer. So it’s all going to have to come from being smarter. I’m a big, big fan of crop breeding and using genetic techniques, etc. etc., but this has got to be … 500 times is not in the cards. I mean, we’d be happy to have 70%. [laughs]But the other thing, again, when you’re thinking of the biofuel side… So I’m in favor of all of that, and in the best of all possible worlds we’d still free up land and then we could benefit the climate by reforesting that land. But remember, the other point is that there are other ways to make energy. Bioenergy is peculiarly inefficient. Sugar-cane ethanol, which is the most efficient biofuel, converts 0.2% of the energy in solar radiation into usable energy. Not 2%, 0.2%. And you put a solar cell out there today and you’ll get 20%.So even if you were foolish enough to say, “Well look, what I want to do for energy is devote some of the world’s best agricultural land,” if you cover that agricultural land in fuel cells you’ll get 100 times more usable energy even on that really good land. And of course, solar cells have gone up in efficiency a lot, lot more, and a lot faster even than crops.So the point is that photosynthesis is necessary for food, it’s necessary for vegetation, for forest, but it’s really inefficient. I mean, photosynthesis is a 3.5 billion year old technology [laughs], and it’s improved only a little bit. If all you want to do is make usable energy, you don’t have to do it through photosynthesis. You use chemical means to get your energy from the sun. That’s why even in the last 10, what, 12 years, we’ve increased the efficiency of even off-the-shelf solar cells 300%. So that’s basically the story. Photosynthesis is a solar energy, it’s just a peculiarly inefficient one, and that also requires a lot of water, a lot of land, a lot of things we need for other purposes.I think we’re much, much more likely to be able to come up with liquid solar fuels, which would be dramatically more efficient than significantly more efficient biofuels.

Corey: I wasn’t saying there’s a 500-fold increase but about a 5x increase, right, 500%. So there’s got to be an assumption about yields built into your calculations. Are you assuming any significant increase in productivity? Because, given what we’ve seen over the last couple of years in genetic engineering, it seems not implausible that you’ll get something like a 5x productivity increase from agricultural plants. How would that affect your calculation and your talk about a calorie gap?

Tim: Well, so first of all, we start with the baseline assumption of roughly historic yield growth rates. And…

Corey: That’s where I think you may be wrong.

Tim: That may be wrong, but actually right now achieving that seems hard, because growth rates in the last 20 years have been lower. And remember, a lot of those growth rates were due to just adding synthetic fertilizer and doubling the area of irrigation. In other words, we need more smart farming. We need those genetic breakthroughs just to achieve that. If we get more, great, even better. In the best case scenario we do that.Now the other thing, and this is getting into my food work, but two thirds of the world’s agricultural land is actually pasture land. And 40% of that, an area almost as much all the world’s crop land, is pasture land that was created out of forest. So another really, really big and important thing to do is to increase the yields of pasture land. That also can be done to some extent with breeding, but most of it is just better management probably.So all those things are incredibly important. And let’s imagine in the best case scenario we actually reduce our agricultural land. Again, most climate strategies assume that we’re going to do that — or not assume, but hope we’re going to do that. Well, then we still have land available, and then the question is how to use it. Most of the time, if you just let that land regrow as forest, for about 50 years you’re going to get more carbon savings than using that land for bioenergy. So still that doesn’t mean the land is free for bioenergy, it just means you have a choice.Then the way to think about this is that, okay, let’s even assume that the bioenergy might be a little bit better. Let’s say we have fantastic high-energy crop yields and they’re better than growing a forest. Well, the point is that if you have 100 acres of land, you’ll still be better off if you take one acre of land and use it with a solar technology and reforest 99, getting the same amount of energy than if you devote 100 acres to bioenergy. The point is there’s always an opportunity cost. You devote a hectare, an acre of land to bioenergy, the cost is not using it for something else. This is not unrealistic.The entire East Coast of the United States — not the entire, but most of it — was deforested a little over 100 years ago, 140 years ago, and it regrew due to two changes. One was the expansion of agriculture in the Midwest, which basically out-competed agriculture on the East Coast. And the second is the decline of bioenergy, because we used to cut down a huge number of trees for all kinds of purposes, home heating, but also charcoal production for steel, etc. etc. So basically, by not using that land for those purposes, the forests regrew, and they sequestered a lot of carbon. And in fact, forest growth of the US is helping to hold down climate change.So it’s all a very simple point. Every acre of land has an opportunity cost. That’s it. You can devote that land to bioenergy, but then the cost is not using it some other way. And it’s just not worth it. We can use land, as I said, for energy purposes, [but] the solution is going to be something that’s much more efficient. Bioenergy is [a)] just inherently very inefficient at converting solar radiation into usable energy, and b) it competes with an inherently limited and valuable asset, which is not just land, but the land that gets enough rainfall that you can actually grow things as well. That’s why. It was just a mistake. It was a mistake that was made because people treated land as free.

Corey: Now it’s an interesting mistake, because not all mistakes turn into policy. I mean, I guess the explanation is kind of obvious, right, there are political interests that want biofuel. We want our farmers to be able to have more markets for their product — we live here in the Midwest — and that drove policy at a national level.It’s interesting, because I grew up in the East Coast with a wood-burning stove; and yet the simultaneous culture of ecology — everyone wanted to be environmentally friendly in Amherst going back a long time, but also a lot of people had wood-burning stoves — it just wasn’t on anybody’s radar screen that this was a problem back in the ’70s and ’80s. Am I right in your diagnosis that this is simply a kind of power politics writ large?

Tim: I think there was a genuine scientific mistake, and I could tell you how that scientific error was made. It was a little bit this renewable, is it free? but there’s another one that I’ll come back to. But it’s true, scientists say things all the time that politicians don’t act on. [laughs] In this case, even before anyone was thinking that biofuel would be good for climate, biofuels were being pushed as a way of increasing farmer incomes. And there was this kind of silly argument that it was good for energy independence, which was never going to be enough to matter at all.We actually had our original ethanol subsidies going back into the ’90s, and then in the early 2000s we get our first biofuel mandate, and no one was thinking about climate at all.

Steve: I grew up in Iowa, so I remember very clearly the advent of ethanol. You’re absolutely right, there was no carbon accounting at that time. Nobody cared or thought at all about that, it was all kind of on the margins: this is another nice product that farmers can produce, and also it helps us stay independent of Middle Eastern oil, for example.But I’m curious about your claim — which I don’t disbelieve, I’m just curious to know the details of — which is that when we switched over to really caring about carbon accounting, some people literally just continued to make the mistake in the way they accounted for the carbon footprint of agriculture or biofuels versus other uses of the land. Can you give us a little intellectual history of how that went?

Tim: Yeah. The mistake, by the way, is literally there’s no cost assigned to land, or another way of saying it is they view all plant growth as offsetting the carbon emitted by burning of the plants, not just additional plant growth. So I’ve already explained a little bit the error. But let me tell you where the source of the error came from, it’s interesting.So you have to go back to 1990. In 1990 you had the first international treaty [report] on climate change [IPCC est. 1988; First Assessment Report 1990], and it required that countries report their emissions. That’s it. Just report your emissions. And they turned to a group of scientists and said, “Tell us how we should report our emissions.” And they said, “Well, look, think of it as a series of accounts. In the energy account, you burn coal, you count the carbon released by burning coal. And on the cement account, you count the carbon released by burning cement. And in the land use account, you cut down a tree, you count the carbon in the tree.”Now notice there’s a little difference here. We count the carbon when we burn coal, not when we mine the coal, but when we burn the coal. For trees, we don’t count the carbon when the carbon is emitted somewhere. We count it the minute you cut down the tree, when we kind of mine the tree. And that rule was adopted for practical reasons. It was the only way to really keep track of what’s going on in the forest.And then they said to themselves, “But wait a second. What if you then burned the tree for bioenergy? Do you have to count the carbon again when it goes up the smokestack?” They said, “No, that would be counting it twice. We don’t want to count it twice.” So they said, “Look, the rule is, for bioenergy count the carbon when you count down the tree.” Now that rule worked for two reasons. One was that the significance of losing a ton of carbon in the forest was exactly the same as the significance of omitting a ton of carbon in the energy account. One ton was one ton. All you had to do was report it.It was also worldwide. You cut down a tree in the US, you burn it in Europe. Europe actually claims fewer emissions because it replaces coal with the tree, but the US reports more emissions because it cut down the tree. And for global accounting, which was the sole goal, it worked out.Now fast forward to the Kyoto Protocol, and it put a cap on emissions. But there were two big differences. First of all, the cap did not apply equally to land use. And secondly, most of the world wasn’t even part of the Kyoto Protocol, including the US. So now there’s a cap on energy emissions in Europe, but no cap in the US. So if you cut down a tree in the US and you ship it to Europe, if Europe doesn’t count the carbon emitted by burning it — and of course Europe is where it really is emitted — it never gets counted, because the US isn’t subject to the cap.What should’ve happened on the Kyoto Protocol, they should have said, “No, no, now you’ve got to count bioenergy when you burn it, because we’re not counting it when it’s cut down.” And nobody noticed. They thought, “No, no, the rule is bioenergy is carbon neutral.” So under the Kyoto Protocol you could literally chop down the Amazon, turn it into a parking lot, ship those trees to Europe, and Europe would count it as 100% greenhouse gas reduction.That theory got incorporated into all these lifecycle calculations for biofuels, it got incorporated in cap-and-trade systems, and it was simply a mistake. Bioenergy was never intended to be carbon neutral, it was simply you count the carbon in one account rather than another. But if all you’re doing is playing with one account, mainly the energy account, you’ve got to count the carbon in that account.

Steve: Was it the case that people with well-functioning brains immediately spotted this problem because it’s kind obvious, but they just said, “Oh, this is not going to be a big deal. We have this slightly imperfect accounting system. As long as it doesn’t go to scale, it’s fine.” Is that what happened?

Tim: No, they didn’t… I don’t want to brag, but I’m the first person who figured out where the error was, and that was in the paper in Science in 2015.

Steve: Wow.

Tim: And the reason I think is that people have this alternative intuition, which was anything that’s renewable is free. Plants are free. Just what you said, Corey: growing plants absorbs carbon; burning plants just puts the carbon back in the atmosphere. It’s a balance. That was not actually the rationale of the Intergovernmental Panel on Climate Change for their national accounting. They said, “No, you count it in the land use account.” But they had this alternative, mathematically incorrect explanation, and that’s where the error came from.I only figured it out because I was going back through some older documents, and I said, “Oh my god, I found… They said count it in the land. Okay, now I understand.” And I went and talked to some of the scientists who were around at the time of the Kyoto Protocol, and they said, “We did that? Oh, we never thought about that.”So here’s another simple, simple, simple way of thinking about it. People think that bioenergy is good because it’s plants, and growing plants is good. And that’s true. Here’s the rule. Growing plants is good. Burning plants is bad. And just because you grew them doesn’t mean burning them is good. But people think it’s all the same thing, bla, bla, bla. No. We need to grow plants, but that doesn’t mean we need to burn them.

Steve: So after your Science paper, did people immediately grasp the essential point, or are there still legions of very confused economists and policy makers and “environmental” scientists out there?

Tim: There are hundreds to thousands of scientists who’ve grasped the essential point, and there are plenty who haven’t. And there’s plenty of stuff that is completely contradictory. You can read stuff by the IPCC, the Intergovernmental Panel on Climate Change, that would say, “Oh yeah, of course this is right.” And then they go and they sight a whole bunch of estimates of large bioenergy potential that were based on this accounting. So basically, you can see the principle and then you sight something, and part of the challenge is — this is a challenge the IPCC has in general, which is sometimes they don’t even think they have to be the job, but they certainly don’t take the time to evaluate all these modeling studies. They just say, “Oh, look, there are modeling studies that say almost no biofuels, there are modeling studies that say huge amounts of biofuels.” They throw them all together, and then people naturally tend to focus on the number in between, in the middle, and they don’t evaluate whether they were valid or what the assumptions were, or whether it was even based on an accounting error.

Steve: But we should trust this kind of process to, for example, estimate the temperature increase from doubling atmospheric carbon, because they couldn’t make equally simple mistakes in that process?

Tim: Well, hopefully they haven’t, but I agree with you even in that take they tend to put all the studies together. The good news about that is that we know perfectly well that [when] you increase carbon dioxide in the atmosphere, you get a lot more warming. But actually, my personal view — well, not just my personal view — it’s clear that there has been an underestimate so far of the amount of warming. Warming has been going on at a higher rate than the mid-level estimates by the IPCC.But anyway, unfortunately it’s really that basic an error, and yeah, you see contradictory views all the time. But basically Corey, you had talked to somebody who gave you your counterargument to me, and that’s still what people think, and it’s just clearly wrong because it treats land as free. It’s a powerful, powerful intuition.Unfortunately, the bigger problem in biofuels is just cutting down trees and putting them in power plants. We’re doing that somewhat in the US, but Europe is doing that big time. What’s happened is that even though most people in Europe realized this was a mistake, it just got a lot of power behind it. Power plants were already doing it, and one of the easier ways to claim you’re solving climate change is just cutting down trees and putting them in your power plant and calling it carbon neutral. So actually it’s going on at a significant scale.

Steve: When you say put them in your power plant, you’re being…

Tim: Burn them. Put them and burn them in your power plant. What’s happened in Europe and to some extent in the US, but more in Europe, is that power plants have literally just said, “We’re going to replace our coal or even natural gas with trees. We’re just going to cut down trees and burn them.”

Steve: That’s absurd.

Tim: It is absurd. It is exactly a result of this error in believing that biomass is carbon free.

Steve: Wow. See, I thought you were saying that euphemistically to represent cut down trees, plant some nice little corn crop or something, and then pretend that because we’re burning, we’re making ethanol, we’re okay or something.

Tim: And most of those trees are coming from the US and Canada, where we cut them down and turn them into wood pellets, and then we ship them to Europe.

Steve: That’s insane.

Corey: What’s the carbon footprint of the shipping?

Tim: Well, the shipping turns out not to be the big number. The real big number is that turning wood into wood pellets and then burning them into electricity is very inefficient. You lose a huge amount of wood and therefore a huge amount of carbon everywhere along the chain. And then when you burn wood, you burn it at a lower temperature, so it produces less electricity than when you burn fossil fuels. So when you count it all, the result is that [if] you’re doubling or tripling the carbon in the atmosphere for 30, 50 years, you’re increasing carbon for decades to centuries. Eight hundred scientists wrote a letter to the European Parliament in January of 2018 saying don’t do this, and they went ahead and did it. They repeated an error they had made before.So this is a gigantic challenge. And part of the problem is, when you treat biomass as carbon free, you are in effect making it more and more valuable to cut down trees to solve climate change. If you basically say, “Well, look, we’re only going to give you the equivalent of $20 a ton for climate mitigation of CO2,” then trees are only so valuable. But if you say, “No, it’s $100 a ton,” they say, “Oh my god, I can make a lot of money off this tree if I cut it down and burn it,” on the mistaken idea that it solves climate change.So this very, very, very basic error, this belief that biomass is inherently carbon free because it starts as plant growth, is now growing. It’s going on in Asia. It’s going on in Europe. It’s going on in parts of the US. Washington State incorporated this error into its new climate law. It’s a huge challenge, and unfortunately it derives literally from this mistake at the time of the Kyoto Protocol.

Corey: To give an idea of how widespread this has become, I was speaking with my father’s real estate agent in Amherst, Massachusetts — again, a very, very green state — and we were talking about how we should handle the renovations of the house, because we want to rent it out. It currently has electric heating, which is thought to be undesirable in the real estate market, and she was suggesting we put in a pellet stove to improve things- When I heard this I first thought I didn’t quite hear right, because Amherst, it turns out, has outlawed gas heating because it’s a greenhouse [gas] producer, but she was recommending a pellet stove to improve upon that, and I just sat there probably for a minute.

Tim: Now the irony of that is that one of the better ways we’re going to be able to solve climate change is through heat pumps. Heat pumps are [nearly] 300% efficient. For every unit of energy you put in, you get three times that amount of energy out in the form of heat. In the old days, resistance electric heating was terribly inefficient. If you have an old house Corey, that’s probably what it was. But actually putting in a heat pump is extremely efficient.

Corey: I’m not familiar with the technology. Can you explain it to us?

Tim: So heat pumps are basically reverse air conditioners. An air conditioner just uses compression to move heat from the inside of the house to the outside of the house. It’s not creating heat, it’s just moving heat around. The heat pump does the opposite. It goes in the opposite direction. Because you’re basically using electricity to compress and then release heat somewhere else, you can actually end up getting a lot more energy in the form of heat than you’re putting in. It’s not [yet] at 300% efficiency. In the past, heat pumps weren’t quite as good at very low temperatures, but I understand they’re getting a lot better, even at very low temperatures. And if worst comes to worst, you supplement it with a tiny bit of resistance heating for the coldest days of the year. I think they’re very good solutions. For residential heating they’re actually very good solutions.

Corey: I want to get your recommendation on policy. You’re a critic of biofuels. We think we’ve made that clear. What would you like to see going forward as regards our energy needs in the US and across the world? And what impact will this have if someone were to adopt your changes on poverty and food availability?

Tim: So let me be clear, I am not really an energy expert. I’m a land guy and an agriculture guy. I can give you my somewhat better than layman’s idea on the energy sector, and then hopefully my expert ideas on land and agriculture. But in the energy sector, my basic view is, look, you go all out as fast as you can, as much as you can, with solar and wind today. People say, “Okay, well that may not solve the problem completely, because we are going to have these storage challenges down the road.” And my answer is [to] work on storage, but that doesn’t mean you shouldn’t do everything you can now, where you can increase solar and wind by a lot without even worrying about storage.One of the things that I’m a big believer in is do the things you know how to do today. Do research for the future, but do the things you know how to do today. Solar and wind are now very cost-effective and getting cheaper and cheaper all the time, and combining those with long-distance transmission lines — this is one thing that Bernie had in his strategy, having to fund these long-distance transmission lines — that’s something we should be going all out [for] today. Similarly, electric cars, not because… Right now a dollar for an electric car is not an efficient way of reducing greenhouse gas emissions, but we have to move quickly to having solely electric cars. And heat pumps would be another good example of where you move in that direction.So that’s on the energy side. And then we have to really hope that storage becomes cheaper.

Corey: Not nuclear?

Tim: The challenge I see with nuclear is that it is phenomenally expensive. I mean, you have all the historical challenges with nuclear of the waste, the risk, etc. etc., of particularly the waste. But it’s phenomenally expensive, and it takes years to get it to work. Everyone says, “Well, look, there may be these alternative forms of nuclear that could work,” and I would be open to putting money into that, or research; but the big plants have turned out to be just phenomenally expensive every time someone tries to build them.

Steve: I think that may be a US-centric view, because for example France gets a lot of its electricity from nuclear power, and I think the Chinese and maybe even the Japanese also are pretty successful with nuclear. So I think in the US, because there’s, some would say, an irrational fear of nuclear waste and the dangers from the nuclear power, it is more expensive.

Corey: You think it’s due to regulation, Steve?

Steve: Yeah, basically. I mean, I don’t we’ve built a new nuclear reactor, a functioning one here in a long time if I’m not mistaken.

Tim: Yeah, but the UK just is paying for one and it’s phenomenally expensive. And then we were subsidizing one here that was abandoned just recently after billions of dollars. I mean, there are ideas for alternative nuclear. I’m game for that. I wouldn’t shut down nuclear power plants for sure. I think that’s crazy. But my feeling is, at least right now, go all out, put your dollars as much and as fast as you can in solar and wind — and of course efficiency, which everyone kind of says as a second thought, but there are huge opportunities.

Corey: So how expensive are they, nuclear power plants?

Tim: Well, I’m not up on it, but they’re 20 cents more per kilowatt hour or something — I don’t know, to be honest — and they keep coming in over budget. I mean, as I said, there was a nuclear power plant that was recently abandoned in the southeast, after billions of dollars.

Steve: I don’t know if you want to go in this direction Corey, since we’re not really, I think I sense, experts on this. But my understanding is that that’s a very US-centric problem, that if you ask people in France or in China, they would say nuclear energy is perfectly viable actually.

Corey: We’re not going to hang this on Tim since he’s a self-professed—

Tim: Yeah. Again, I’m open on the nuclear issue, but every time I start focusing on it, that’s the impression I get.But anyway, on the land-use side, where I do have some thoughts, we had this report with 22 recommendations [laughs] — big, big menu items, they’re big, only one of which is get out of bioenergy — the way to think about it is, we need to make more efficient use of land. That means more efficient diets. So we recommend cutting our beef consumption, which really matters a lot when you factor in land use.

Corey: Keto Steve, keto Steve, Mr. Beef.

Steve: Yeah, I think the paleo keto lifestyle has the maximum carbon footprint, because you’re eating things at the top of the food chain.

Corey: Is there any sort of guilt? Is there a guilt module in your brain that’s responding at all to this, Steve?

Steve: You know, it’s interesting. I’ve never sat down and calculated, relative to say my driving habits, how big my change in diet is in terms of carbon footprint.

Corey: So because you’re doing do one thing that’s bad, you haven’t bothered to do this thing that might be a smaller footprint too.

Steve: Yeah.

Tim: But Steve, are you eating beef or are you eating other meat?

Steve: No, I’m mostly eating chicken and fish, so in that sense I’m not eating kobe beef every night or anything like that. But definitely compared to someone who’s a vegetarian, it’s obvious to me that I have a bigger carbon footprint.

Tim: Beef is off the charts compared to everything else, and a lot of that is due to the huge land-use requirements for beef. I have some papers on that where we basically …

Steve: Yeah, I don’t eat a lot of beef actually.

Corey: But you do ridicule people who eat soy.

Steve: I don’t ridicule people, but… In fact, I haven’t done any research on this in—

Corey: What’s the term I heard? “Soy boy”?

Steve: Soy boy.

Corey: Soy boy, you called somebody soy boy.

Steve: But I think that’s a…

Corey: That sounds like ridicule.

Steve: Yeah, but that…

Corey: Oh, it’s not ridicule?

Steve: That’s not supposed to be an actual nutritional — it’s more of a cultural judgment than a nutritional one.

Corey: Oh, it has no implications for what you might recommend that somebody do, just calling them that. [Tim laughs]

Steve: Well, so there are separate claims. There’s one claim that you shouldn’t eat too much soy because of, I guess, estrogen-like hormones…

Corey: Yeah, because you’re masculine.

Steve: And this is all kind of like “bro science” nutrition, so I don’t really know whether any of this is true. But then there’s a second thing, that people who do opt to eat a lot of soy tend to be of a certain cultural or personality type, and that’s what the joke is more about when you call someone a soy boy.

Corey: Your second appellation was “Brooklyn,” like people who eat soy must live in Brooklyn.

Steve: Exactly, yeah. A lot of soy boys in Brooklyn.

Tim: But you know, the biggest development this year was we now have these plant-based hamburgers that taste like hamburgers.

Steve: Yeah, if you can grow meat directly without having to deal with the cow, I think that could decrease a lot the carbon footprint of eating meat.

Tim: Yeah. Actually, this company Impossible Foods has made a plant-based burger that really tastes like a hamburger. Burger King among others is rolling it out nationwide, and you probably can’t tell the difference.

Corey: So let me jump in. I think you’re right, you can’t tell the difference. But as a friend of mine once said, “It tastes like beef, and it hits your stomach and it feels like vegetable.” It’s just gone. You don’t feel it after you consume it. That, I think, may be an impediment to people who actually want the full nutrients.

Tim: That’s interesting. Maybe. It’s got plenty of fat in it, and plenty of protein, so in that sense it doesn’t have more carbohydrate. That may be true of veggie burgers that have more carbohydrate, but this one really is replicating the nutritional profile of beef, whatever good or bad.

Steve: From my own personal taste I think I could be perfectly happy. And at one time I was almost a vegetarian. I ate only a little bit of chicken and fish and was mostly eating vegetable protein. But this keto thing sort of forces you, when you cut your carbs, to basically eat tons of meat-like stuff.

Tim: Yeah. To be honest, I really think that is the key on the diet side. I mean, I don’t think that guilt alone, let alone eco guilt, is going to drive it. But I do think that when you can get a plant-based hamburger and it tastes exactly like what you want, and it’s actually cheaper, I think there’s a chance a lot of people will switch.

Steve: And will that be a big impact? Since you said like a third … How much of land is pasture land? It’s quite a bit, right?

Tim: We have about three billion hectares of pasture — just people who don’t know, the continental US has about 800 million hectares — there are three billion hectares of pasture land in the world. And over a billion of that was historically forest. If you didn’t need that billion hectares of land for beef, you could reforest it, and that would have a big effect on the climate.I just did a little calculation. This is extreme, but I estimated that if you reduce global beef consumption by 75% for about 35 years, you could regrow enough carbon to offset about 20% of human greenhouse gas emissions. And the real issue is we need [to do] both. We’re now at the stage where we need to both almost completely get rid of carbon from the energy sector, and we need to dramatically reduce the emissions from agriculture, and we need to reforest land. So we need all of the above.A lot of climate strategies just kind of assume that this land is available to reforest, but in the real world it only becomes available to reforest if we a) dramatically increase the efficiency of grazing for the beef and dairy we do produce, but like double or triple that, and then b) hold down beef consumption, beef in particular. Only 25% of the world’s population eats a fair amount of beef. That’s it. So we basically need that 25% per capita to cut its consumption by about half.

Corey: Yeah, I’m not one of these people. But I want to ask a question about people like me who eat a fair amount of fish and some chicken. What fraction of land is dedicated to poultry compared to beef?

Tim: A very small fraction of land is dedicated to poultry compared to beef. I’ve never actually calculated it, to be honest. It must be in the order of maybe of 15% of all crop land but not out of all agricultural land.

Steve: I think you can look up the carbon footprint of a serving of chicken versus beef. It’s quite a bit lower, so you’re definitely better.

Tim: Yeah, but most people who calculate that don’t attribute a greenhouse gas cost to the land use. So the same issue happens that we’ve been talking about in the bioenergy context, the same issue happens in lifecycle calculations for diets.

Steve: But the way you want to do the calculation… So suppose I had free-range cows grazing on a pasture, would you compare that to planting the biggest, most massive trees on all that land if I wanted to—

Tim: No, I actually had a paper where I basically said on average how much carbon have we lost to produce each pound of beef, and from vegetation as a global average, and that’s the number I’m using. But it almost doesn’t matter, the details. If you ascribe any reasonable amount of land-use cost, it dwarfs everything else.The reciprocal of what I said, which is that roughly a third of the world’s grazing land was originally forest, is that a lot of what’s grazing land was native grazing land. But the problem is that we’ve used that up long ago, because there was no alternative purpose for that for humans, other than to graze it for cattle and sheep and goats. So when we expand our beef production, it comes at the cost of forest.That’s the point. We need to kind of hold things down. At the end of the day, we’re going to still have beef and we’re going to still use that native grazing land, and we’re going to still use a lot of waste products for feed, like citrus pulp and brewers’ yeast and all this kind of stuff. But at the margin, it comes out of forest, so we basically need to hold down that consumption for that purpose. That basically means that each of us can actually have a big effect just by reducing our beef consumption.

Corey: I have a question about unintended consequences again. If you were to push people away from beef, I understand that moving them to chicken may not have much of an impact. Does moving them to fish have a serious impact on the ecosystem or on carbon production?

Tim: So fishes are interesting. We are dramatically overfishing.

Corey: That’s what I was thinking.

Tim: And there are huge environmental implications of that. But in part because of that, all additional fish consumption for the last 20 years has come from aquaculture. So as the population grows, all of the additional fish have to come from aquaculture.Aquaculture also has environmental effects, although as a whole it is… The greenhouse gas balance of aquaculture is more like chicken than beef, but it still has a variety of significant effects. So the question is, if we want to expand our aquaculture, we have to do it well. Most aquaculture is actually in Asia and it’s very low tech, and you need to do it with circulating ponds and things like that.Ultimately we probably need to have kind of indoor aquaculture. And that’s a possibility. And then there are other issues related to aquaculture. One of the issues is that we actually use a lot of wild fish as food for aquaculture. We can’t do that anymore. We have to reduce that, to not increase it. That means you have to substitute fish oil. What all fish need is some fish oil. Fish oil actually comes from algae. When you were talking about algae before, the most valuable use of algae production is likely to be fish oil.

Corey: Oh, the fish oil doesn’t come from fish? Fish oil doesn’t come from fish? Is that your…

Tim: No, the fish get it from algae.

Corey: Interesting. No production internally.

Tim: I don’t think so. I mean maybe, there may be some from fish, but there’s a whole lot that comes from the algae. You can also make a fish oil from genetically engineered canola oil, and that would be another alternative. But basically, over time aquaculture has the potential to be a very efficient form, and relatively environmentally beneficial form, of animal food.

Corey: But as you know, there are environmental downsides to aquaculture. So have you examined those, whether it’s waste products from the fish, or…

Tim: Yeah, there are a whole series of them. It uses a fair amount of land. It uses a lot of water. You get diseases on wild fish. You displace wild fish, particularly in inland lakes, with aquaculture fish like tilapia. So there are a huge number of environmental effects. But the bottom line is, producing food has large environmental effects. I mean, that’s just the reality.The goal is to do that with lower environmental effects. There’s no such thing as food production with zero environmental effects. The closest thing to food production with zero environmental effects would now be farm-raised mussels because they’re filter feeders, [laughs] and they’re probably taking excess nutrients out of nearshore waters. But with the exception of that, the goal is just to hold down the effect to the extent we can.

Steve: Hey Tim, we’re almost out of time. I want to drop one kind of explosive question on you and just see how you feel about it, given that you’re an expert in this area.If I let an immigrant into my first-world country who is coming from, say, a subsistence farming background or maybe even he’s a hunter gatherer, and suddenly the week later he’s driving around in a Dodge Charger, living a first-world lifestyle, isn’t that an incredible increase per capita in our carbon footprint, and therefore aren’t there ethical issues associated with that?

Tim: [laughs] What a question. Well, it’s true. Every American generates a lot more greenhouse gas emissions than pretty much anybody anywhere else, so if you increase the American population, the cost of that is more emissions. Now of course, we don’t live only for emissions. We live for lots and lots of other reasons, and solving climate change is only one of many, many goals. Another goal is to harbor refugees. Another goal is to build our culture. So in the real world there are all these trade-offs, and that’s probably one of the smaller reasons to think about in dealing with our immigration policy.But yeah, it’s true [for] every American, not just immigrants. Every time you have a kid, right? The reality is that I have two kids, so my hope is that my two kids contribute enough to the world to offset their greenhouse gas emissions. And of course, I fly around all over the place giving lectures about solving climate change while generating greenhouse gasses. The thing is there are trade-offs, and in the real world we just have to muddle through.

Corey: I was hoping that we’d have time to go into your bio Tim, but I think we’ve had such a long, interesting discussion about biofuels to bring us to the end of this program. But I want to thank you for coming on the program. This has been a pleasure.

Tim: Well, thanks for having me. It was real fun.

Steve: Thanks again.

Creators and Guests

Stephen Hsu
Stephen Hsu
Steve Hsu is Professor of Theoretical Physics and of Computational Mathematics, Science, and Engineering at Michigan State University.
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