Economist and HKS Professor Wolfram Schlenker says declining R&D funding for new agricultural technologies and protectionist agricultural trade policies could make climate-related food shocks more severe.

The warning lights are blinking for the world’s food supply. At least that’s what 150 Nobel Prize and World Food Prize laureates said in a recently published open letter calling for a “moonshot” effort to begin ramping up of food production to meet the demands of a global population projected to reach 9.7 billion people by 2050. Harvard Kennedy School economist Wolfram Schlenker, the Ray A. Goldberg Professor of the Global Food System, says meeting those goals amid the headwinds of climate change will require urgent policy changes and, in some cases, policy reversals. Even as crop yields are under stress from rising temperatures and extreme weather events, public spending on research and development of new, climate-resistant crops and other food technologies has declined, Schlenker says. Additionally, many countries are also erecting more protectionist barriers around their domestic agricultural sectors, undermining the global free trade in staple food commodities that is essential to preventing severe agricultural shocks that can result in civil upheaval, mass migration, and global instability. In a groundbreaking 2009 study, Schlenker found that crop yields fall precipitously after a certain heat threshold. The study’s conclusions were validated just three years later when a heat wave over the U.S. corn belt saw yields drop by 25%. With 700 million people already classified as undernourished and the world having at least temporarily breached the crucial 1.5 degrees Celsius warming standard in 2024, the economics of food in the climate crisis era may be the most important problem nobody’s talking about. Schlenker joins PolicyCast host Ralph Ranalli to discuss the ticking food crisis clock and explore policy changes that could make a difference. 
 

Policy recommendations

Wolfram Schlenker’s recommendations
  • Limit beggar-thy-neighbor agricultural policies where countries impose export restrictions when food prices rise. Specifically, implement the Declaration on Sustainable Agriculture passed at COP28 by ensuring that the World Trade Organization has an enforcement mechanism that limits trade restrictions in agricultural markets following climatic events.
  • Reverse the current decline in public R&D funding for agricultural technologies. Private companies, which currently conduct most of the R&D, do not have the correct incentives to innovate when there are positive spillovers on others.  
  • Ensure that the current Social Cost of Carbon—the cost of emitting an extra ton of carbon dioxide—reflects the impacts on all countries and not just the U.S., as climate change is a global problem. 


Episode notes

Wolfram Schlenker is the Ray A. Goldberg Professor of the Global Food System at Harvard Kennedy School. An economist and engineer by training, he studies the intersection of climate, agriculture, and the global economy. His research interests include:

  • The effect of weather and climate on agricultural yields and migration
  • How climate trends and the U.S. biofuel mandate influences agricultural commodity prices
  • How pollution impacts both agricultural yields and human morbidity. He is a research associate at the National Bureau of Economic Research. He currently serves on the Board of Reviewing Editors at “Science.”

Schlenker holds a PhD in agricultural and resource economics from the University of California, Berkeley, a master’s in engineering and management sciences from the University of Karlsruhe, in his native Germany, and a master’s in environmental management from Duke University. 

Ralph Ranalli of the HKS Office of Communications and Public Affairs is the host, producer, and editor of HKS PolicyCast. A former journalist, public television producer, and entrepreneur, he holds an BA in political science from UCLA and a master’s in journalism from Columbia University. 

Scheduling and logistical support for PolicyCast is provided by Lilian Wainaina. Design and graphics support is provided by Laura King and the OCPA Design Team. Web design and social media promotion support is provided by Catherine Santrock and Natalie Montaner of the OCPA Digital Team. Editorial support is provided by Nora Delaney and Robert O’Neill of the OCPA Editorial Team.  

Preroll: PolicyCast explores research-based policy solutions to the big problems we’re facing in our society and our world. This podcast is a production of the Kennedy School of Government at Harvard University.

Intro (Wolfram Schlenker): I think agriculture crucially depends on trade. Because what happens with agriculture is still so impacted by weather shocks. And the lucky thing about the world is that not everybody gets hit by a weather shock usually in the same year. We have some years when they’re more correlated, like El Niño, which sort of pose threats. But in general, it works out like a perfect hedging against risk. So if you look at individual farms, they can get a 60, 70% drop in yields in a particular year because it was just a really bad year. If you aggregate out those four crops we talked about earlier over the whole world, the fluctuation in total production are within plus minus 5%. Because if somebody does really badly, somebody else does really well.  

Intro (Ralph Ranalli): The warning lights are blinking for the world’s food supply. At least that’s what 150 Nobel Prize and World Food Prize laureates said in a recently published open letter calling for a “moonshot” effort to start the immediate ramping up of food production to meet the demands of a global population projected to reach 9.7 billion people by 2050. Harvard Kennedy School economist Wolfram Schlenker, the Ray A. Goldberg Professor of the Global Food System, says meeting those goals amid the headwinds of climate change will require urgent policy changes and, in some cases, policy reversals. Even as crop yields are under stress due from rising temperatures and extreme weather events, spending on research and development of new, climate-resistant crops, and other food technologies has declined, Schlenker says. In a groundbreaking 2009 study, Schlenker found that crop yields fall precipitously after a certain heat threshold. Though criticized at the time, the study’s conclusions were validated just three years later when a heat wave over the U.S. corn belt saw yields drop by 25%. Additionally, many countries are also erecting more protectionist barriers around their domestic agricultural sectors, undermining the global free trade in staple food commodities that is essential to preventing severe agricultural shocks that can result in civil upheaval, mass migration, and global instability. With 700 million people globally already classified as undernourished and the world having at least temporarily breached the crucial 1.5 degrees Celsius warming standard in 2024, it may be the most important problem nobody’s talking about. Except here. Wolfram Schlenker joins me to talk about how to save the future of food.

Ralph Ranalli: So, Wolfram, welcome to PolicyCast.  

Wolfram Schlenker: Thank you so much for having me.  

Ralph Ranalli: We try not to be too driven by the daily news cycle on this podcast, but I have to say, as someone who cares about the ability of policy to impact issues like the climate crisis and who grew up in Southern California, I’ve been watching and thinking a lot about the wildfires that have caused historic levels of destruction in the communities of Pacific Palisades and Alta Dena. So I wanted to ask you, as an economist who studies possible climate related impacts and even potential climate related catastrophes, what was your reaction to watching the fires, and to the news—which was much less widely reported—that in 2024 the world at least temporarily passed the very important 1.5-degree Celsius threshold for global warming. To me it those seem to be blinking red warning signs, and I was just wondering about your reaction.

Wolfram Schlenker: So I have a bit of a personal story on the wildfires. When I just graduated from my Ph. D. I started out at UC San Diego. And at the time, there was a postdoc there, Anthony Westerling, and his entire career was about forecasting fires in California. So I’m gonna reveal to you how old I am, but this was, like, in the early 2000s, in 2003. And even back then, there were all those forecasts about how fire risks would increase, what would happen. So this is not something that’s unexpected. People have been warning about this for 20 years. The forecast that people have made 20 years ago, if anything, were underestimates. It turned out to be worse than we had anticipated.

So, this is sort of a clear signs of things to come. Now, one thing to keep in mind, though, is it’s sort of a convolution of different factors. On the one hand, we have nature changing. But there’s also policy angle. How do we adapt to it? How do we design cities? Can we do anything to make them less prone to spreading fires? There is really great research over the last 10 years about how certain building codes and other sort of government intervention can actually help us from fire-spreading. Economists always emphasize about people having the right incentives. So if you do something to save your own home, that should have a huge incentive for you to engage in this activity.

Ralph Ranalli: Right.  

Wolfram Schlenker: With fire risks—and this is in this famous paper by Judson Boomhower and Patrick Baylis—they show that there’s as much benefits on your neighbors as it is on you if you put in a fire-resistant roof, because the fires spread less. Given that there’s this huge externality, there might be sort of a role for governments to step in. So that’s sort of my take on it. Obviously, it’s not something that’s new. California always had fires. But sort of the densely population centers combined with changing climate is sort of just amplifying those risks.  

Ralph Ranalli: Yes. Growing up there, you understand that wildfires are a natural feature of the ecosystem. But over the decades when I’ve gone back to visit family and watching development push further and further into areas where fires are more likely, I’ve had this sense that it was increasingly a place living on borrowed time, particularly when you add man-made global warming and climate instability to that. But speaking of blinking red warning signs, I wanted to turn to your real area of expertise, which is the interaction between food, climate, and economics. And it seems like the concern about the world’s food supply was really ramped up very recently when 150 Nobel and World Food Prize laureates signed an open letter calling for a “moonshot effort” for the immediate ramping up of food production. And of course a moonshot means an urgent effort where everyone pitches in—scientists, policymakers, private industry, the public. They said it was needed because global food supply and demand is now getting to be what they called a “tragic mismatch.” Collectively, the world is going to need to ramp up food production by 50 to 70% over the next two decades in order to feed 9.7 billion people by 2050. We’re now closer to the year 2050 than we are to 1999. What did you make of that open letter, in terms of it being a wakeup call and, whether it can potentially get more popular attention to this issue?  

Wolfram Schlenker: I think it’s great that they’re raising the awareness. I would like to separate my answer into two parts: sort of the immediate effect and the more medium-term effect. I think, humankind has done a tremendous job in increasing agricultural production through the Green Revolution. So, if you look, for example, at the United States, which is one of the major maize—or in the United States you call it corn—growing region of the world, before around 1940, yields were completely flat. So, the only way to increase production was basically to increase the growing area. which has its own issues with deforestation, biodiversity intrusion, and so forth.  

But since 1940, we have this very strong upward trend. Yields have actually increased six-fold. It’s one of the sectors of the economy with the highest productivity increase of any sectors in the U.S. economy. It obviously has come with some downsides, too, with pollution and runoff of fertilizer and so forth, but I’ll put that aside for now. So, production increases have been tremendous. Between 1940 and 1980, they almost rose exponentially, so, far outpacing population growth. Since 1980, it started to slow a little bit, and we see now more like a linear trend. So, tremendous progress, not just in the United States, in many other countries as well. And that’s really been able to feed the world. You know, the world basically feeds itself on four basic stable commodities. They’re soybeans, wheat, rice and maize. They account together for about two-thirds to three-quarters of the calories that we humans consume.

Ralph Ranalli: Right, about 70%.  

Wolfram Schlenker: Yeah. So either directly because we eat it, like wheat in the bread, or indirectly because they’re used as feedstock. So those commodities have really… the production has gone tremendously, up to the point that governments felt the need to actually help farmers by increasing the price to set asides in the United States or other restrictions in the European Union. There were a lot of agricultural policies. So this is sort of the first part of my answer here. In real inflation-adjusted terms, prices are still pretty low despite recent inflation, especially for the basic commodities. And we’re doing a good job. In a way, actually, farmers are worried that the prices are too low and the government tries to help them.

Now, in the medium to longer term, we’ve already seen climate having a really— that’s my second answer here—climate having a real impact on food production. So there’s stories around the world, right? The heat wave in India in 2022, where wheat production dropped by 10%, and as a result, [Indian President Narendra] Modi put on an export ban on wheat, which led to repercussions around the world. There’re some estimates that wheat prices went up by 6% for other countries. Same in the United States.  

Ralph Ranalli: Yeah, 2012, right?  

Wolfram Schlenker: Exactly 2012.

Ralph Ranalli: It was a heat wave that hit the Corn Belt, and the yields dropped something like 25%?

Wolfram Schlenker: Correct. This is, this is a funny story. We had this paper in PNAS in 2009…  

Ralph Ranalli: PNAS is the proceedings of the National Academy of Sciences, right? In that paper you analyzed temperature data from 1950 to 2005.

Wolfram Schlenker: Correct, and so, any time you do empirical study, you use past data, there’s this question how relevant they are for the future. So I gave this talk in Iowa to farmers as well as the chief breeder of Monsanto, and he in 2011 basically said “This paper is so wrong, it’s not even close to being right.” Which was, as a junior assistant professor, kind of shocking. But in our defense, since you just mentioned 2012, 2012 came along, and if you believe our model, which basically emphasizes this crucial role of extreme heat on corn yields, the forecasts were dead on. They couldn’t have been more accurate in predicting how the sample, what would happen. We’ve seen this in other countries now, too, so this article has survived over time. I’m pretty confident there’s something to it, although there’s a bit of a puzzle whether it’s actually extreme heat or soil moisture deficit because the two of them are highly correlated. But it is a very, very good, predictor of yield declines.

Ralph Ranalli: Can you explain, in terms that a non-food-economist would understand, how basically what you found was that yield growth increased gradually up to a certain temperature point and then yields really drop off?  

Wolfram Schlenker: That’s the gist of the article. So basically the idea is if, if you were to run your own greenhouse and you could set your optimal temperature, like for corn or maize, according to our article, you would send it at like, 29 to 30 degrees Celsius, which is like 84 to 86 degrees Fahrenheit. And you would keep it constant at that. That’s when the plant thrives the most. If it’s colder, it’s not good for the plant. On the other hand, if it’s hotter, it’s also not good for the plant. And there’s this huge asymmetry in the sense that being above the temperature threshold is much worse than being below it. So when you have fluctuation, you lose some by being below, you lose some by being above. But being above is much worse than being below.  

Ralph Ranalli: Right. That’s about 86 degrees for corn, right?  

Wolfram Schlenker: Correct.  

Ralph Ranalli: So, with climate change, with increased global heat, you have many more hot days that can push you toward the edge of that productivity cliff.  

Wolfram Schlenker: There’s just huge yield declines, because what we basically use is a very simple measure that’s called degree days, which is basically measuring by how long and for how much you exceed these thresholds. So, think about your threshold of, let’s pick 86. If you’re basically at 87, you’re one degree above. If you’re 88, you’re two degrees above. 90, you’re four degrees above. And it’s additive in both time or, how much you’re above. So you can either be four days at 87 or one day at 90 degrees. Both times you get four. And so what happens basically when the maximum temperature rises, you can see a very sharp increase in these extreme days that we currently don’t see a lot because it’s truncated at the top.  

And as you mentioned earlier in 2012, it’s just a very, very good predictor of what happens to yields, because these conditions, when it’s very hot, is basically signaling you two things. A, the plant wants a lot of water, because it’s hot. B, it doesn’t have a lot of water, because if there was water, there would be evaporative cooling, which basically cools the atmosphere. So there’s really hot temperatures, and this comes back to the soil moisture I mentioned earlier.’ They’re just signaling you a condition that’s just a dire condition for the plant, which is basically signaling that you want water, but you don’t have it, and that’s when it starts to shut its stomach and also starts to wilt and so forth. And it’s that interplay that really predicts yields very, very well. If you just focus on temperatures above 86 Fahrenheit, and you could disregard anything that happened below the threshold, you can explain more than half of the variation in corn yields from year to year. So it’s really this really predominant driver and really strong signal.

Ralph Ranalli: It is challenging, because agriculture is a very complex system. You mentioned that irrigation can have a mitigating effect on temperatures, and I remember reading that in one of your studies. Can you talk about that a little bit more?  

Wolfram Schlenker: Sure, so, drought is a relative concept, right? It’s like, there’s a water demand and a water intake, and when that’s out of balance, then you basically see the plant suffering. So if it’s very hot, your water demand goes up, but if you irrigate, you can sort of meet it. You basically have the plant suddenly wanting a lot of water. If you provide it to them, you might still see some decline in yields, but it’s much less than if they run dry and they basically dehydrate. And that’s the question: how you can adapt by putting more irrigation.  

Now, I should mention that there are some countries which use very elaborate irrigation systems. Israel is one of them, but that usually works only best for high valued crops like cherry tomatoes or other things that are produced. Commodity crops like corn aren’t really that irrigated. Rice is a different thing, where we often use flood irrigation. But rice and soybeans and wheat aren’t that widely irrigated. And the fear is that if you were to use a lot of irrigation, A, it would make the crop much more expensive and that, sort of going back to where we started, it would sort of take away some of the gains we’ve made in making food cheaper and accessible for people. And B, it might also have effects on whether they’re sustainable in terms of pumping too much, running out of groundwater. We’re seeing this in some regions of the world, like India, that if you pump too much groundwater then you can’t sustain it forever  

Ralph Ranalli: So, I think we saw in the last election that the price of food is a big deal. It has lots of repercussions, and that’s been true throughout history. You look at the, the analysis of the fall of the Roman empire, for example, right? Historians and scientists have said a major factor was that there was a 20% decrease in food production, which led to widespread turmoil in the empire and helped contribute to its fall. And coming all the way up to this past November, a lot of the talk was prices at the supermarket. How troublesome is it for, say, the U. S. economy if we see a big, drop in yields like what some of the studies have predicted? What are the ripple effects from a major drop in U. S. food production?  

Wolfram Schlenker: I think I completely agree with you. I think food prices is just one thing of the most salient issues that consumers face because they need to eat, they need to buy every week, they go to the grocery store, so it really weighs heavily in their decisions. I think in terms of U. S. yields, the commodity prices of the end product that people pay for in the supermarket is a small fraction. So even if they go up by a factor of two, it wouldn’t necessarily impact the prices of the goods in the supermarket that much. So I don’t think most of the damages would be felt in the United States. I think it’s in other countries. If you live on like a dollar a day… You know, we have the sustainable development goals to end hunger by 2030, which we’re very far away from—700 million people are still facing undernutrition. Those people have a hard time if you double the prices because the basic cost of a diet and those raw commodities are suddenly getting almost to the entire income that you have if you live a dollar or two dollars a day. So for them, the impact would be much more severe. And we’ve seen after the COVID pandemic that the progress we’ve made in reducing world hunger and malnutrition is partly reversing, because while supply chains held up surprisingly well in developed countries during COVID, the reduction in trade and so forth has really had some negative effect on other countries.

Ralph Ranalli: And that’s particularly an issue in places like Africa, where their domestic food production is seeing the effects of climate change. And the great inequity of that is that these are places that have contributed the least to the climate problem in terms of their output of CO2 and other greenhouse gases. And yet they’re going to be feeling the biggest effects.

Wolfram Schlenker: So, they’re certainly not responsible in terms of emissions. Also, to what you mentioned earlier about those thresholds for crops. It seems to be very hard through crop varieties to adjust certain crops to different heat sensitivities. So in a follow up paper with other authors, with David Lobel and Justin Costano Roberts, we looked at African yield and we again found those sort of thresholds effects. And since Africa is a continent that’s warmer to begin with in many areas, they would actually suffer even more from climate change than places that start at a colder baseline, since they’re shifting even more of their temperature distribution in this extreme heat that you mentioned earlier. So yes, if you look at, for example, the U. S. government has what they call a social cost of carbon, which is the cost imposed by emitting one ton of CO2 into the atmosphere. And a large part of those damages occurs to countries in the global south, especially Africa, both in terms of human mortality as well as agricultural impacts.

Ralph Ranalli: I’m curious about your take on the public conversation on this. Right here, with just you and I talking, the seriousness and the gravity of this issue is right there for anyone to see. But if you look at the public conversation writ large, to me, it seems like there’s this unfathomable lack of conversation about climate and food. And we seem to be talking not only about the wrong things, but in the wrong ways. Take the price of gasoline. When gas prices go up, you have a lot of consternation and debate. But using that gasoline drives climate change, which is going to make growing food much harder, and the amount that the average U. S. family spends on food is four times what it spends on gasoline. So it seems like this is what we should be worried about. And then we also talk about climate migration, right, but almost always in terms of people and not food. Admittedly it’s very difficult and sometimes dangerous, right, for a family to pick up and move from a place where climate and extreme weather effects are making their lives unlivable. But it’s another thing entirely for a commercial farmer to pick up and move his 5,000-acre farm from one place to another. There just aren’t that many 5,000 acre places where you can grow food. Why do you think we don’t talk about this topic more? And is there a way to push it more into the public consciousness. Besides you and I doing this podcast, of course.

Wolfram Schlenker: So you raised several issues here and I think this would take hours to answer all of them, so I’m gonna give you my best shot at a few aspects of them. So, I’m with you. As a bit of a background, I think economists tend to be optimistic that if you give people the right signals, people adapt, deal with issues and go forward. So, I’m not in the camp of the most alarmist that think the world’s gonna end because of climate change as much as I think we should do something about it, just to be clear. But I also don’t want to overstate the severity of it. But you just mentioned climate migration and other things. I think one thing that developed countries often underestimate is the spillovers between the world and conflict spreading between nations and how climate can be a very strong driver about this.

So you mentioned earlier the fall of the Roman Empire. There’re papers that look at a 1,500 years of European history, and it’s just amazing how much they line up with weather events. Like the Little Ice Age, when there were low crops. We have the episodes of witch burning, and people looking, basically, for somebody to blame the dire situation on. Then there’s other episodes, like the Enlightenment, aligns when crop yields were very good in Europe. So it sort of had this really big influence on human society.  

You might say, well, after industrial revolutions, is that still true? But you mention just the global south, a large share of the population often still works in agriculture. A lot of them might be displaced. They might migrate. They might see better opportunities elsewhere. The 5,000 acre farm is really a US example. In most of those countries, they have less than an acre. But, it’s hard for them. How can they reallocate? Do they have specific skills? Do they find more jobs in manufacturing? Do they migrate to become immigrants in other countries? We had a paper that sort of showed how asylum applications to the European Union responded to weather shocks over the maize growing area all around the world and where farmers were growing crops. And so I do think this interconnection is sort of this amplifier about how climate impacts, which predominantly will be in the global south, can then again impact other countries because they sort of lead to this upheaval and repercussions throughout the world. So in that sense, I agree with you that it’s sort of underappreciated.  

The other angle I wanna talk on, which I think is lately becoming more close to my heart, given the current policy debate and tariffs imposed by the U. S., the export ban by India, and so forth. I think agriculture crucially depends on trade. Because what happens with agriculture is still so impacted by weather shocks. And the lucky thing about the world is that not everybody gets hit by a weather shock usually in the same year. We have some years when they’re more correlated, like El Niño, which sort of pose threats. But in general, it works out like a perfect hedging against risk. So if you look at individual farms, they can get a 60, 70% drop in yields in a particular year because it was just a really bad year. If you aggregate out those four crops we talked about earlier over the whole world, the fluctuation in total production are within plus minus 5%. Because if somebody does really badly, somebody else does really well.  

And this is really one area where agriculture is very different from other things we produce. If you say “Oh, I don’t want to have EV cars from China” and I put 100% tariffs on it, you can have your own domestic car production company, but their output doesn’t fluctuate by 60, 70% year to year. And so we need trade to basically smooth those shocks. And if we take that away, we would make food prices way more volatile. We would discourage storage, which helps smoothing out shocks across years, even in biblical terms, like the good years followed by the bad years and how we insure against them. And we’re sort of moving away from that. And it’’ one of the biggest innovations we have to insulate ourselves against those shocks, it’s basically to trade with one another, and basically keep those markets open.  

It’s interesting because the Conference of the Parties in 2023, for the first time, had a declaration on agriculture. These are basically the, the talks on, on climate change.  

Ralph Ranalli: The UN Climate Change Summit, the annual COP conference?  

Wolfram Schlenker: Correct. And for the first time they had a declaration of agriculture. In Point 5, there are calls for open, fair access to food to everybody around the world. And I think it’s an important point we need to keep in mind that it would make the world much less safe if we don’t have this trade in agriculture and people face famines and other shocks. But this is sort of a long-rounded way to get back to your initial question about why don’t we talk much more about this, especially in developed countries. And, you know, economists love free trade. We always advocate it. But I think for the first time I’m seeing also a rationale for why some governments might be wary about doing agricultural trade, especially if you’re an importer. If you’re an importer of wheat, of Indian wheat, and suddenly a government that was up for reelection says, “Oops, our prices are rising, let’s stop all exports.” You are at their goodwill, and your local population is suddenly saying, “Where is all of our wheat? Our prices are going up.” Very much because the other country put on export restrictions.

And so there is potentially this national security risk of being dependent on imports on food. And again, you mentioned earlier about how much we spend on food, how dependent we are on it. And in that sense, I can see more of a rationale for why some governments want to either have very strict enforceable rules about free trade, or subsidize their local agriculture sector a bit more to be less dependent on others. So there are some of my colleagues, it’s not my area of research, but that work in international security, and they have documented how basically Russia tried to take over a lot of Ukraine’s wheat exports, and how that sort of impacts voting in the UN Security Council. So a lot of African countries who used to get wheat from Ukraine are now getting it from Russia. And not surprisingly, they’re not voting against Russia because they depend on their wheat imports. So it could also be seen as sort of a strategic tool in influencing international diplomacy.  

Ralph Ranalli: You just mentioned working with colleagues who approach this from related but different perspectives. You’re working with the Salata Institute for Climate and Sustainability at Harvard, which is a relatively new multidisciplinary center at Harvard and we’ve had Jim Stock, the director and Harvard’s Vice Provost for Climate and Sustainability, here on PolicyCast if our listeners want to go back and listen to that episode. And you’ve said how great it is to be working in concert with people who are also bringing their perspectives and their very, very high-level research and scholarship to this area. Can you talk a little bit about the work of some of the people that you collaborate with, how that has a multiplier effect on your work, and how you enable greater mutual understanding by working together?

Wolfram Schlenker: Sure I’d be happy to. One of the, the main reasons that really attracted me to coming here to the Kennedy School was really sort of the Salata Institute and its vision and how it’s set up as a provostial initiative and sort of trying to foster cross campus collaboration. It’s really wonderful. I think there’s sort of several ways. So in the past, I started out as UC San Diego, as we mentioned at the beginning, and back then the Scripps Institute of Oceanography. What I learned from them was basically getting really detailed weather data, which sort of allowed us to construct this measure of extreme heat much better and led to this article. I don’t think without the interaction with them, I would have been able to really do this on sort of the level that we did.

I think nowadays here at Harvard, I think there’s three areas that are—I’m not necessarily working with them—but I’ve interacted and seen their work. One is remote sensing. So I think there’s a lot, lot more we can do, and I have articles jointly, not here at Harvard, but with colleagues who are from other disciplines using remotely sensed data. And this is especially valuable for crop yields around the world, where we often don’t have good government data. We now have sensors like Landsat and others which give us very detailed data on crop progress in areas where we before didn’t have data and couldn’t measure things well, as well as even soil moisture and so forth. So working with natural scientists, remote sensing specialists really helps me in getting better representation about the food supply and the food situation around the world.  

The second one is this interaction with biodiversity. There is sort of this inherent conflict. So I talked about the COP of the climate, UNFCCC that we talked earlier. There’s another COP which I think gets less recognition, which is for biodiversity. They just had one down in Colombia. And Jeannine Cavender-Bares, who has joined Harvard too, is leading a big effort there on measuring biodiversity from space. And there is sort of this inherent conflict about, you know, we want to increase agricultural production, so we increase the growing area. That often comes at the cost of deforestation. It infringes on species richness and biodiversity and other issues. So there’s a Harvard-wide working group on biodiversity, and for me, it’s sort of interacting, especially with the ag and the food supply, is a very important research area going forward. That’s number two.  

And number three, I’m not directly involved, but one of the first initiatives, started before I arrived this past summer, is the methane initiative of the Salata Institute.  

Ralph Ranalli: Right. We’ve had Rob Stavins on this show talking about the methane initiative, and why methane and natural gas are a big concern for short-term acceleration of global warming.

Wolfram Schlenker: And it’s not just natural gas and so forth, it’s also cows. They produce a lot of methane. Again, back to the remote sensing, there’s really cool work coming out of Harvard measuring South American methane emissions from cattle. It’s important because companies actually have very stringent goals of how much they want to reduce their methane emissions, partly because there’s directives by the European Union and so forth on sort of measuring their scope emissions. And I think there’s going to be a lot of progress being made. There’s now feed additives like Bovaer that basically reduces methane emissions quite substantially and looking at those innovations, trying to measure it, trying to get it into potentially, a trading system for pollution permits. That’s really a frontier that requires several angles, not just the scientists who measure it, the policy makers who designed the right policies, and the business school basically brings in the business leaders who want to measure this and get it on the shelves. So, it’s really a multi-faceted effort.  

Ralph Ranalli: So, I wanted to return for a minute to that open letter from the 150 Nobel and World Food Prize laureates. One of the things they said was that we have to do this now, because it can take 10 to 15 years of lead time to do some of these measures that are going to make a difference. I mentioned Rob Stavins and Jim Stock, and we’ve also had David Keith on the show, and his big thing is geoengineering; he thought it was time to start considering that before it was too late for it to have an impact. But in agricultural science, there are also some technological fixes that are potentially impactful if we start working on them soon. Like improving photosynthesis for wheat. Or developing cereals that can source nitrogen biologically so they can grow without fertilizers. Or research into indigenous crops, or reducing food waste by improving fruit shelf life. Can you talk about some of those things that, if we started doing them now, might make a difference?

Wolfram Schlenker: I think it’s like with anything in a climate crisis, the right approach is often all of the above because we often don’t know yet which of the technologies will actually turn out to be the most successful. So I wouldn’t want to be pitching one specifically that’s making big progress. Like, I think Africa is using not enough fertilizer. Part of the reason is, that it is just much more expensive to get fertilizer there. It’s like a much higher transportation cost. It’s also highly energy intensive, actually. There is a startup, I think, Pivot, that is now basically what something you mentioned. It’s basically using geoengineered bacteria, which basically are much better at nitrogen fixation. And so they dip the seeds into it, they plant it. There’s a colleague, Tavneet Suri, over at MIT Sloan, who has a field trial in Kenya, that seems to… I mean, I don’t want to jump her study before it’s out, but I think that’s one avenue that people are pursuing.

Ralph Ranalli: Okay. We’ll keep it between you and me.  

Wolfram Schlenker: Yeah, none of your listeners will ever hear about this. But, I think that the reason for this time lag is that, crop development cycles just take a long time, right? We are like, often coming up with new crossbreeds. We grow them. It takes a year to usually grow them. It’s not like something you can just replicate in two weeks and then start over. You grow it for a year, you refine it, and then you get approval and so forth. And so this whole process of getting new crop variety often takes 10 to 15 years. It’s not just something you can turn off immediately. Now, there are some other interesting things. We’re using more and more AI, even in those fields. So they’re surprisingly good at predicting what kind of crossbreeds might actually be successful in certain characteristics. So I think companies are starting to experiment with that. That might speed up the process a little bit. I think that is one avenue going forward as well, bringing those modern technologies in.  

But I think there’s also a really big role for policy. Because I think part of the reason Africa is producing less—it’s not just the cost and so forth—there’s also institutional issues, like credit market access, high inflation, other things that keep farmers from potentially growing the most they could. And there is this intertemporal problem: I sow in the spring, and I get my harvest late in the fall in the northern hemisphere. And so I basically have to bridge this with either loans. If there’s huge inflation, I don’t have credit, I might not optimally allocate things. So we also have to work on those policy angles to get people to optimally plant and grow crops.  

Ralph Ranalli: Well, that is the perfect segue because at the end of every PolicyCast episode, we ask our guests for some specific policy recommendations that they think that our listeners who might be policy makers or policy influencers should support. So, if you were in control of the levers of policy power for a day, what couple of policy recommendations would you put forward that you think would make a difference and that people who are interested in policy and involved in policy should get behind?

Wolfram Schlenker: Let me give you three. I think the one and most immediate one is, because I think people underappreciate it, is what I mentioned earlier—to ensure again that the WTO is working. We had the Uruguay Round in the 1990s. It led to a decrease in tariffs and distortions in the ag sectors. I have this feeling we’re moving in the opposite direction right now. And so reinforcing what COP 23 said on the declaration of agriculture. There needs to be international agreement on not using beggar-thy-neighbor policies and amplifying food policy shocks to neighbors if climate shocks hit. So that’s sort of more in the international diplomacy negotiation realm.

The second thing is I think we should increase, again, the amount of public expenditures, and that’s what the letter said, on R&D. It has historically been much higher. It’s come down a lot, and most of the R&D now is done by private companies. And again, as an economist, I can sort of see why we want to incentivize private companies to do things, but there are very important spillovers. And whenever there are spillovers, companies might not have the perfect incentives to innovate. In a way, if you’re a monopolist, it’s actually a really weird situation. You might not actually want to innovate. Because if you innovate and food becomes more abundant, prices drop and farmers are willing to pay less for seeds. So the monopolist has actually not the right incentives here. It’s interesting because oftentimes we think monopolists, when we talk about innovations, have good incentives because they capture all the benefits. But here, given how inelastic demand is, if you have a lot of progress in food production, prices drop, the farmers complain, they might not buy your seeds anymore, and so forth. So, number two would be increased R& D budget for—they call it moonshot—but even just going into new crop varieties and so forth, which we have decreased very rapidly over the last several years.

The third one is maybe highly technical, but I think it’s highly consequential. The United States, as I mentioned earlier, there’s an article by Michael Queensland saying the most important number you’ve never heard of is the social cost of carbon. EPA currently proposed to revise it. It’s going up from, like, 53 to 200. It’s very important because when you do sort of evaluations, which projects make sense or not, you basically have to look at the costs to be imposed by emitting carbon. And that’s an important component. There’s a huge push by the incoming administration and some states to use a U.S.-only number, meaning we only measure the damages inflicted on the U. S. Now in a global problem like climate change, if every country only focuses on their own, we’re not gonna get the efficient outcome. And as we mentioned earlier in this podcast, there’s also a lot of interlinkages between countries. We can’t just think, this is the impact on the U. S. and it doesn’t impact us what happens in the rest of the world, not even just from a moral value, even just from economic and security reasons and so forth. So I think as a policymaker, I would very strongly lobby, and again, this is sort of sounds maybe very technical, but if you look at the U. S. only number, it would be very small. There’s a chance that they will succeed in the courts and this will be what we drive our policy for, but I think it will be highly misleading and actually have huge impacts on sort of how we evaluate certain policies. So we should use a global cost there when we evaluate projects.

Ralph Ranalli: Well, Wolfram, thank you so much for being here. I’m really glad you were able to share your knowledge and your research, and I promise we will do our small part here at PolicyCast to raise the awareness in the public discourse about this vital issue. So thank you so much for being here.

Wolfram Schlenker: Thanks so much again for having me.

Outro (Ralph Ranalli): Thanks for listening. If you liked this episode, please don’t forget to subscribe to PolicyCast on Apple Podcasts or your favorite podcasting app, so you don’t miss any of our important upcoming episodes. And please leave us a review while you’re there. And if you’re enjoying PolicyCast, we encourage you to check out some of the other great HKS shows, including the Environments Insights podcast from Professor Robert Stavins and the Harvard Environments Economics Program. Just search for “Environmental Insights” on your favorite podcasting app. And until next time, remember to speak bravely, and listen generously.