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The Leading Voices in Food

E237: Agriculture impacts climate more than you think

Hosted by: Kelly Brownell (Duke)
May 24, 2024

Is it possible to decarbonize agriculture and make the food system more resilient to climate change? Today, I’m speaking with agricultural policy expert Peter Lehner about his climate neutral agriculture ideas and the science, law and policy needed to achieve these ambitious goals. Lehner is an environmental lawyer at Earthjustice and directs the organization’s Sustainable Food and Farming Program.

Based in New York, Peter Lehner is the managing attorney of Earthjustice’s Sustainable Food & Farming Program, developing litigation, administrative, and legislative strategies to promote a more just and environmentally sound agricultural system and to reduce health, environmental, and climate harms from production of our food. Peter is one of the leading experts on the impact of agriculture on climate change and is the author of Farming for Our Future; the Science, Law, and Policy of Climate-Neutral Agriculture. From 2007–2015, Peter was the executive director of the Natural Resources Defense Council (NRDC) and the NRDC Action Fund. Among other new initiatives, Peter shaped a clean food program with food waste, antibiotic-free meat, regional food, and climate mitigation projects. From 1999–2006, Peter served as chief of the Environmental Protection Bureau of the New York State Attorney General’s office. He supervised all environmental litigation by and against the state. He developed innovative multi-state strategies targeting global warming and air pollution emissions from the nation’s largest electric utilities, spearheaded novel watershed enforcement programs, and led cases addressing invasive species, wildlife protection, and public health. Peter previously served at NRDC for five years directing the clean water program where he brought important attention to stormwater pollution. Before that, he created and led the environmental prosecution unit for New York City. Peter holds an AB in philosophy and mathematics from Harvard College and is an honors graduate of Columbia University Law School. Peter is on the boards of the Rainforest Alliance and Environmental Advocates of New York and a member of the American College of Environmental Lawyers. He helps manage two mid-sized farms and teaches a course on agriculture and environmental law at Columbia Law School.


How does agriculture impact the climate? And I guess as important as that question is why don’t more people know about this?

It’s unfortunate that more people don’t know about it because Congress and other policy makers only really respond to public pressure. And there isn’t enough public pressure now to address agriculture’s contribution to climate change. Where does it come from? Most people think about climate change as a result of burning fossil fuels, coal and oil, and the release of carbon dioxide. And there’s some of that in agriculture. Think about tractors and ventilation fans and electricity used for pumps for irrigation. But most of agriculture’s contribution to climate change comes from other processes that are not in the fossil fuel or the power sector. Where are those? The first is nitrous oxide. Nitrous oxide is a greenhouse gas about 300 times more potent than carbon dioxide. And it comes because most farmers around the world and in the U.S. put about twice as much nitrogen fertilizer on their crops, on the land, as the plants can absorb. That extra nitrogen goes somewhere. Some of it goes off into the water. I’m sure your listeners have heard about harmful algae outbreaks or eutrophication of areas like the Chesapeake Bay and other bays where you just get too many nutrients and too much algae and very sick ecosystem. A lot of that nitrogen, though, also goes into the atmosphere as nitrous oxide. About 80% of nitrous oxide emissions in the U.S. come from agriculture. Excess fertilization of our hundreds of millions of acres of crop land.

Quick question. Why would, because the farmers have to pay money for this, why do they apply twice as much as the plants can absorb?

Great question. It’s because of several different factors. Partly it is essentially technical or mechanical. A farmer may want to have the fertilizer on the land right at the spring when the crops are growing but the land may be a little muddy then. So they may have put it on in the fall, which is unfortunate because in the United States, in our temperate area, no plants are taking up fertilizers in the fall. Also, a plant is like you or me. They want to eat continually but a farmer may not want to apply fertilizer continuous. Every time you apply it, it takes tractor time and effort and it is more difficult. So they’ll put a ton of fertilizer on at one point and then hope it lasts for a while, knowing that some of it will run off, but hopeful that some will remain to satisfy the plant. There’s a lot of effort now to try to improve fertilizer application. To make sure it’s applied in ways just the right amount at the right time. And perhaps with these what’s called extended release fertilizers where you put it on and it will continue to release the nutrients to the plant over the next couple of weeks and not run off. But we have a long way to go.

Okay, thanks. I appreciate that discussion and I’m sorry I diverted you from the track you were on talking about the overall impact of agriculture on the climate.

I think what’s so exciting about this area is that everyone cares about our food. We eat it three times a day or more and yet we know very little about where it comes from and its impacts on the world around us. It’s wonderful to be talking about this. The second major source of climate change impact in agriculture is methane. Methane is another greenhouse gas much more powerful than carbon dioxide. About 30 times more powerful over a hundred years and about 85 times more powerful than carbon dioxide over 20 years. Which is I think the policy relevant time period that we’re looking at because we’re all trying to achieve climate stability by 2050. And where does methane come from? A little bit comes from rice, but the vast majority of it comes from cows and from manure. Cows are different than you and me. They can eat grass, and their stomachs are different, and release methane. Every time they breathe out, they are essentially breathing out this potent greenhouse gas methane. This is called enteric methane and it’s the largest single source of methane in the United States. Bigger than the gas industry or the oil industry. The other major source of methane is manure. Our animals are raised in what are called concentrated animal feeding operations. They’re not grazing bucolically on the pasture, they are crammed into buildings where there may be thousands, or tens of thousands, or even hundreds of thousands of these animals. Those hundreds of thousands of animals produce a vast amount of manure, whether it be say pigs in North Carolina or dairies in many States, or cattle or chicken. All our meat nowadays is grown in these concentrated areas where you get concentrated manure and that is often stored in these lagoons. These big pits of poop basically. And that, as it decomposes in this liquid environment, what’s called anaerobically , releases a tremendous amount of methane. That’s the second largest source of methane in the country after the cows belching. So you have nitrous oxide and you have methane. And then the third way agriculture contributes to climate change, which is different say than the fossil fuel sector, is by changing the land itself. Agriculture uses a tremendous amount of land. Think about it. When you go around, what do you see? You see agriculture uses about 62% of the contiguous United States; 800 million acres of land for grazing; or almost 400 million acres of land for cropland. Healthy land before it’s been used for agriculture has a tremendous amount of carbon in the soil and in the plants. Just think about a forest with all the rich soil and the rich vegetation. When that is cleared to be a cornfield, all that carbon is lost and essentially it goes into the atmosphere as carbon dioxide. And that soil after that can’t absorb any more carbon. Healthy soil is absorbing carbon all the time and most agricultural soils are not. So that release of carbon when you convert land to agriculture and that continuing inability to sequester carbon is another major way that agriculture contributes to climate change. So these three ways: nitrous oxide, methane and carbon from soil are all important contributors to climate change that don’t really fit most people’s model of what drives climate change – burning coal or oil and releasing carbon dioxide. But the bottom line is if we don’t address agriculture’s contribution to climate change, no matter how successful we are in reducing our fossil fuel use, we are very likely to face catastrophic climate change. Agriculture’s contribution to climate change is so significant. Far more than the indicated by many figures. We can’t achieve climate stability without addressing agriculture as well. Agriculture drives about a quarter or a third total green climate change.

Given how important this is, why don’t people know more about it? And does industry play a role in that?

Industry plays a big role, as does politics. Industry – and by industry we mean the food industry. And you’ve covered this before. It’s very concentrated industry where usually two or three or four firms control the market, whether it be for seeds or retail or beef or chicken or pesticides. It’s a very, very concentrated industry with tremendous political power. They have done their best to ensure, first of all, the agriculture industry doesn’t even have to report their greenhouse gas emissions. Every other industry has to report their greenhouse gas emissions. The big polluters have to report. On the other hand, agriculture was able to obtain a rider in Congress. That’s an extra provision on a budget bill starting about a decade ago that prohibits EPA from requiring agricultural facilities to report greenhouse gas emissions. So unlike most areas, agriculture doesn’t even have to report their emissions and industry certainly wants to keep it that way. Also, as I was explaining, agriculture contributes to climate change in a way that is different than what we normally think about. I think that added complexity has just meant it is harder for people to understand. And third, there’s a tremendous amount of mythology in agriculture. People think or would like to think that their food comes from this nice family farm with a few animals and a few diversified crops on the hillside. And that in some sense was the reality 50 or 100 years ago, but now it’s not the reality. While there’s still lots of small farms like that by number, those produce very little of our food. Most of our food is produced in these gigantic animal factories that I mentioned earlier or in gigantic monoculture chemical-dependent agricultural operations. So, we have this disconnect between what is the mythology of agriculture and where our food comes from and the reality of it. People really don’t want their myths disrupted.

Given the importance of these issues, what are some of the main ways that the impact of agriculture on climate can be changed?

That’s another exciting part of this. That there’s a lot of things that can be done to reduce the impact of agriculture’s contribution to climate change. And we know this because there are a lot of producers who have piloted these programs, who’ve implemented these programs and these practices on their own operations to reduce the climate impact. And they’ve been successful. So these can be, for example, rotating crops instead of having the same crop year after year after year, which really depletes the soil. You can have different crops in different years and each crop puts a little different in the soil and takes a little different from the soil. As a result, very often you end up needing less artificial pesticide and fertilizer, both of which contribute to climate change. You can manage your animals different. You can manage your manure differently. For example, if manure is treated and handled dry, as opposed to in these wet manure lagoons, it produces very, very little methane. Instead of producing tremendous amounts of methane, it produces almost none. So, if we manage manure differently, we can significantly reduce methane emissions. And of course, there’s what we think of as the demand side. In the same way that we think about LED light bulbs or more efficient cars as part of our energy transformation, we can use our land and food more efficiently. We waste a tremendous amount of food. Maybe 30-40% of the food we produce is wasted. That’s crazy. It’s all the effort and the greenhouse gases from producing the food are wasted if the food is wasted. Even worse, the food is dumped into a landfill for the most part where it releases more methane. And it’s inefficient. We have a system that very heavily subsidizes meat production, but meat uses, particularly beef, a tremendous amount of land because cows need a lot of land the way their biology requires land and time. So we have almost 800 million or 700 million acres of land devoted to cattle grazing that could be storing carbon. Then it takes about 15 pounds of grain to get a pound of beef where people can eat the grain directly much more efficiently. So there’s a lot of practices that we can do at every stage of the process to reduce the climate impact of agriculture. The challenge is that it’s only on a couple percent of American cropland or very little portion of our food is produced that way.

So Peter, let me ask you a question about that very point you’re on. We’ve recorded a series of podcasts on regenerative agriculture. Some of the most interesting podcasts we’ve done from my point of view. And they’ve included scientists who’ve studied it, policy people who look into it, but also farmers who have done this. I’m thinking particularly, well, three names pop into mind, but there are more. So Nancy Ranney, who ran a ranch in New Mexico for cattle, Gabe Brown, a regenerative farmer in North Dakota, and Will Harris from Georgia were all people we spoke to. I got the sense in each of those cases that these people were converting to this new model of farming because of what they cared about. It was their own passions that led them to do this and belief that a different system of agriculture was going to be important for the future. They were doing it for that reason, rather than any incentives from the government or policies that were encouraging, things like that. So there will be a small number of such people who would do it because they’re passionate about it. I’m assuming that number will grow, but never fast enough to really do anything to scale like we really need it. So I’m ultimately you’re going to need policies in place to ensure these things happen in more and more farms. Are there particular policies that are oriented this way that you think might be especially helpful?

Kelly, you are spot on. I know Nancy and Gabe and Will, and they’re terrific. They are pioneers and they are showing that we know this works. We’re not looking at ideas that might work. We are looking at practices that we know work because of what they and others like them have done. As you said, they’re doing it because they believe it’s the right thing. We’ll get some farmers that way, but we need policy to move from 2% of American crop land to 92% of American crop land. So, how do we do that? One is the current farm bill is very important. The farm bill is the most important environmental law nobody’s ever heard of. It dates back to the depression. It’s renewed every five years. Congress is debating it right now. It was supposed to be renewed last year, but they couldn’t get their act together. So they may or may not be able to reauthorize it this year. But the farm bill in one section provides a tremendous amount of money for nutrition assistance. And you’ve probably talked about that, what we call the Supplemental Nutrition Assistance Program. In another part of it, it provides tremendous amounts of subsidies to farmers, about $20 billion a year of subsidies to farmers. Right now, those subsidies really are not designed to encourage farmers to adopt the practices that you talked to Nancy or Gabe or Will about. These practices that I was talking about earlier and that sometimes are called regenerative, sometimes agroecological, organic farming is often a part of that. These $20 billion of subsidies though, could be redirected, reshaped somewhat and not necessarily radically, but reshaped and focused on encouraging farmers to adopt these practices that can help mitigate climate change. And importantly, the same practices, and as I’m sure the folks you’ve talked to said, also help them be more resilient to climate change. They can better help the producer better withstand floods and droughts and temperature extremes. So there is a tremendous upside from this. We are already spending $20 billion a year on farm subsidies. Let’s start spending it more intelligently in a way that really addresses our needs.

Do you see signs that things are moving in that direction?

I wish I did. There are some signs that we’re moving in the right direction. The Inflation Reduction Act, which Congress passed a couple of years ago, was the first time Congress ever linked agriculture and climate change. In the 2018 Farm Bill, there’s no mention of climate change. And when we were working on that with members on the Hill, there was really no overt conversations about climate change. Fortunately, things have changed. So, a step forward is that we’re talking about climate change. And in the Inflation Reduction Act, Congress provided $20 billion to go to programs that are established under the Farm Bill. So, 20 extra billion dollars to these Farm Bill conservation programs and required that that money be spent on practices that will reduce greenhouse gas emissions, essentially help us mitigate climate change. And that, again, was the first time Congress linked agriculture and climate change. Super important. Part of what’s going on now on the Hill is a fight to ensure that money that the Inflation Reduction Act provided stays. There are those in Congress that would like to raid those funds and put them to other purposes, which we think would be a big step backwards. So that was really great opportunity. As to the Farm Bill money itself, there’s definitely some conversations, particularly among the Democrats, to ensure that all of the Farm Bill programs are a bit more climate-focused. But we’re far from consensus on that. So, we’re making a bit of progress, but right now Congress is, I think it’s fair to say, not at its most functional. And so the type of policy discussions we need, and an honest discussion of how can we help American farmers shift to practices that are better for them, for the communities, upwind and downwind and around them, better for climate change resilience and climate change mitigation. We’re really not yet having that conversation as robustly as we need. Hopefully we’ll be able to get to a place where the politics will allow us to have that. And frankly, this podcast and other conversations are really important to educating people so we can have that conversation.

When you’re trying to make policy advances, having public support for it can be a real asset. Do you see signs that the public is becoming more aware of this, that they’re urging their political leaders to move on this front?

For sure. The public is very much concerned about climate change. Every poll shows that. And people are concerned about it both as citizens and as consumers. So, if you follow the food marketing world, what you see is that many surveys show that consumers are very interested in the climate impact of their food choices. And far more than was the case a couple of years ago. And they want to know how can I buy food? How can I eat food that is climate friendly, that helps us stabilize the climate? And industry is responding to that. Now, some industry is responding to that by deceptive advertising. You may have seen that the New York Attorney General recently sued JBS, the world’s largest beef company, for misleading statements about the climate-friendliness of their beef. So some companies are talking more than they’re doing, but others are trying to respond to consumers’ interest in more climate-friendly food. You see a growth in plant-based foods, plant-based milks, because plant-based foods have a much, much lower climate impact than meats, particularly beef. And so consumers are interested in that, and that market is responding. And I think you’ll see more of that in governmental procurement as well. Governments that are trying to think about how can we, say New York City, reduce our climate footprint while a big part of a city’s climate footprint is the food it purchases, say for New York City schools. And a city can take action by trying to buy lower climate impact foods. And that would be foods produced in a way that you’ve talked about with regenerative practices and also lower climate impact, such as more plant based. So, I think we’re seeing a lot of progress on that for sure.

So Peter, related to this, what would you think about some kind of labeling system on food products that gives an environmental score, let’s say?

I personally like the idea of labels. I’m not an expert by any stretch. I do remember that not too long ago, New York City required restaurants to label or have on the menus the calorie content of food. And that provision was later adopted by the Affordable Care Act and now is required of chain restaurants. And Trump tried to roll that back. So we litigated to try to preserve that and get that requirement reinstated in the Affordable Care Act successfully. And during that, I learned that labels really make a difference. Calorie labeling on menus does in fact help people make more informed choices and often better choices. And there’s no question, again, I’m not an expert. You probably know much more, but for example, the added sugar labels make a difference and others. So I think as a whole, labels can make a big difference. Now, environmental footprint is a complicated multifaceted issue because something may create harm to water. It may create harm through toxic, say pesticide residue, or it may have a big climate footprint. How do you put all of that into a simple label? It’s a complicated question. But I do think there’s interest in having particularly climate, the climate impact food be identified on the label. And perhaps we will move in that direction.


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