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The Leading Voices in FoodAuthor: Duke World Food Policy Center
The Leading Voices in Food podcast series features real people, scientists, farmers, policy experts and world leaders all working to improve our food system and food policy. You'll learn about issues across the food system spectrum such as food insecurity, obesity, agriculture, access and equity, food safety, food defense, and food policy. Produced by the Duke World Food Policy Center at wfpc.sanford.duke.edu. Language: en Genres: Health & Fitness, Science, Social Sciences Contact email: Get it Feed URL: Get it iTunes ID: Get it Trailer: |
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E276: Climate Change - A little less beef is part of the solution
Episode 276
Friday, 20 June, 2025
Interest and grave concern have been mounting over the impact of agriculture and the food choices we all make on the environment, particularly on climate change. With natural weather disasters occurring much more frequently and serious threats from warming of the atmosphere in general, it's natural to look for places to make change. One person who has thought a lot about this is our guest today, Dr. William Dietz of George Washington University. He's been a prominent voice in this space. Bill, you're one of the people in the field I respect most because our relationship goes back many years. Bill is professor and director of research and policy at the Global Food Institute at George Washington University. But especially pertinent to our discussion today is that Dr. Dietz was co-chair of the Lancet Commission on the global syndemic of obesity, under nutrition and climate change. Today, we'll focus on part of that discussion on beef in particular. Interview Summary Bill, let's start out with a basic question. What in the heck is a syndemic? A syndemic is a word that reflects the interaction of these three pandemics that we're facing. And those are obesity, under nutrition, and we've also called climate change a syndemic insofar as it affects human health. These three pandemics interact at both the biologic and social levels and have a synergistic adverse impact on each other. And they're driven by large scale social forces, which foster clustering and have a disparate impact on marginalized populations. Both in the developed and equally important, in the developing world. Here are a couple of examples of syndemics. So, increased greenhouse gases from high income countries reduce crop yields in the micronutrient content of crops, which in turn contribute to food insecurity and undernutrition in low and middle income countries. And eventually the reduction in crop yields and the micronutrient content of crops is going to affect high income countries. Beef production is a really important driver of the climate change, and we're a major contributor in terms of the US' contribution. And beef production drives both methane and nitrous oxide emissions, and in turn, the consumption of red and processed meat causes obesity, diabetes, colon cancer, and cardiovascular disease. And finally, obesity, stunting and nutrition insecurity occur in the same children and in the same population in low- and middle-income countries. Okay, so we'll come back to beef in a moment, but first, help us understand the importance of agriculture overall and our food choices in changing climate. Well, so I think we have to go back to where this, the increase in mean global surface temperatures began, in about 1950. Those temperatures have climbed in a linear fashion since then. And we're now approaching a key level of increase of 1.5 degrees centigrade. The increase in mean surface temperature is driven by increased greenhouse gases, and the US is particularly culpable in this respect. We're it's second only to China in terms of our greenhouse gas emissions. And on a per capita basis, we're in the top four with China, India, and Brazil and now the US. And in the US, agriculture contributes about 10% of greenhouse gas emissions, and about 30% of fossil fuels are responsible for greenhouse gas emissions. But when you look at the actual contribution of car use among the fossil fuel use, it's pretty close to the contribution of greenhouse gases from agriculture. The important point here is each one degree increase centigrade in air temperatures associated with a 7% increase in water vapor. And this is responsible for the major adverse weather events that we're seeing today in terms of increased frequency and severity of hurricanes, the droughts. And I learned a new term from the New York Times a couple of days ago from the science section, which is atmospheric thirst. I had trouble understanding how climate change would contribute to drought, but that same effect in terms of absorbing moisture that occurs and drives the adverse weather events also dries out the land. So increasingly there's increased need for water use, which is driven by atmospheric thirst. But that increase in air temperature and the increase in water vapor, is what really drives these storms. Because in the Pacific and in the Atlantic and the Gulf of Mexico, this increase in air temperature is associated with an increase in water temperature, which further drives the increase in the severity of these storms. Thanks for that background. Now let's get to beef. You and I were not long ago at the Healthy Eating Research conference. And you gave what I thought was a very compelling talk on beef. We'll talk in a minute about how much beef figures into this overall picture, but first, tell us how beef production affects both climate and health. And you mentioned nitrous oxide and methane, but how does this all work? Cattle production is a big driver of the release of methane. And methane comes from cow burps. The important thing to understand about methane is that it's 80 times more powerful than CO2 in terms of its greenhouse gas emission. And that's because it has a very long half-life when it gets up into the atmosphere? Well, actually it's interesting because the half-life of methane is shorter than the half-life of nitrous oxide. So, it's an appropriate target for reduction. And the reduction has to occur by virtue of reduced beef consumption, which would reduce beef production. The other piece of this is that nitrous oxide is derived from fertilizer that's not absorbed by plants. And the application of fertilizer is a very wasteful process and a huge percent of fertilizer that's applied to crops is not absorbed by those plants. And it washes into the Mississippi River and down to the Gulf of Mexico. But also, increases the genesis of nitrous oxide. And nitrous oxide is an even more powerful greenhouse gas than methane. About 260 times more powerful than CO2 with a very, very long half-life. So, as a target, we really ought to be focused on methane, and if we're going to focus on methane, we need to focus on beef. You could imagine people who are opposed to these views on climate change making fun of cows burping. I mean, are there enough cows, burping enough where the methane that's coming out is a problem? Yes. Maybe a better term that we can use is enteric fermentation, which is in effect cow burps. But enteric fermentation is the major source of methane. And nitrous oxide, the same thing. The agricultural system which supports cattle production, like the feedlot fattening from corn and wheat. The genesis of nitrous oxide is a product of fertilizer use and fertilizer use is a real important source of nitrous oxide because of the amount of fertilizer which is not absorbed by plants. But which washes into the Mississippi River and causes the dead zone in the Gulf, but also generates an enormous amount of nitrous oxide. So, between those two, the enteric fermentation and the origin of nitrous oxide from fertilizer use, are a lethal combination in terms of increasing greenhouse gas emissions. And it's important to know that those greenhouse gas emissions are associated with important declines in crop yields. Crop yields have declined by about 5% for maize for wheat, for soybeans, and somewhat less for rice. These crop yields have yet to affect the US but are clearly a problem in the Global South. In your talk, you cited a paper by Scarborough and colleagues that was published in the Journal Nature Food that modeled the environmental impact of various diets. Could you please explain what they found? This was a really nice study of four diets in the United Kingdom. Actually it was five diets. They looked at vegans, vegetarians, low meat eaters, medium meat eaters and high meat eaters. And looked at the contribution of these diets to the genesis of methane, nitrous oxide, and also importantly, land use and water use. And the most expensive, and the most detrimental environmental impact of these diets, were the among the high meat eaters. These were substantially greater than than the genesis of for example, methane by vegans. For example, high meat eaters generated about 65 kilograms per day of methane compared to vegans, which generated only four kilograms per day of methane. And when you reduce beef, and there were two lower categories, these measures come much more into line with what we'd like to have. The low meat eaters generate about half of methane that the high meat eaters generate. This is also true for their genesis of nitrous oxide. And importantly, the land use among vegans and vegetarians is about a third of the land use required for the production of beef. And water use by meat production is about twice that generated by the water use by the production of plant-based diets. I think these are important data because they, they really reflect the importance of a lower meat consumption and higher plant-based diet. Not just in terms of greenhouse gases, but also in terms of land use and water use. Not to mention health. Not to mention health. Yes. I think it's important to continue to remind ourselves that beef consumption is associated with a variety of chronic diseases like obesity, like diabetes, like colon cancer and like cardiovascular disease. So, there's this double whammy from beef consumption, not only on the climate but also on human health. In your talk that I heard it was interesting to see how you interpreted this information because you weren't arguing for no beef consumption. Because you were saying there could be tremendous benefit from people going from the high beef consumption category to a lower category. If you could take all the people who are consuming beef and drop them down a category, it sounds like there would be tremendous benefits. People could still have their beef but just not have it as often. Right. I think that's an important observation that we're not talking about the elimination of beef. We're talking about the reduction in beef. And the Eat Lancet Commission pointed out that protein consumption in the US was six times what it should be in terms of human needs. And a lot of that protein comes from beef. And there's this belief, widespread, popular belief that beef is the most important source of protein. But comparisons of plant-based diets and plant-based proteins have an equivalent impact and equivalent absorption pattern like beef and are equally nourishing. That's a really important thing to make prominent because people are thinking more and more about protein and it's nice to know there are various healthier ways to get protein than from a traditional meat diet. Well, one of the, one of the important reports from the dietary guidelines advisory committee was to reclassify lentils, beans and peas as proteins rather than vegetables. And I think that's a, something which has not been widely appreciated, but it gives us a real important area to point to as an alternative protein to beef. Bill, on this calculus, how important is the way the cattle are raised? So, you know, you have big cattle farms that might have a hundred thousand cattle in a single place being raised in very close quarters. And it's industrial agriculture, the kind of the epitome of industrial agriculture. But more and more people are beginning to study or experiment with or actually implement regenerative agriculture methods. How much would that help the environment? That's kind of a complicated question. If we just start with beef production, we know that grass fed beef has a healthier fatty acid profile than feedlot fat and beef. But the total generation of greenhouse gases among grass fed beef is greater because they're fostered on land for a longer period of time than those cattle which are committed to feedlots. My understanding is that most of the cattle that go to feedlots are first raised on grass and then moved to feedlots where they're fed these commodity products of corn and wheat and, and maybe not soy. But that feedlot fattening is a critical step in beef production and is associated with overcrowding, antibiotic use, the generation of toxic dust really. An enormous amount of fecal material that needs to be adequately disposed of. It's the feedlot fattening of beef is what adds the adverse fatty acid content, and also contributes to the local environment and the damage to the local environment as a consequence of the cattle that are being raised. Appreciate you weighing in on that. Let's talk about what might be done. So how do we go about increasing awareness, and the action, for that matter, in response to the contributions of beef production to climate change? It begins with understanding about the contribution of beef production to climate change. This is not a well understood problem. For example, there was a study of 10 major news sources a couple of years ago which asked what the major contributions were of climate change. And they surveyed a hundred articles in each of 10 sources of information, which were popular press like New York Times, Washington Post, etc. And, at the top of that list, they characterize climate change as a consequence of fossil fuels. Whereas a recognition of the contribution of the agricultural system was at the bottom of that list and poorly covered. It's no surprise that people don't understand this and that's where we have to start. We have to improve people's perception of the contribution of beef. The other thing is that I don't think we can expect any kind of progress at the federal level. But in order to build the critical mass, a critical focus, we need to look at what we can personally change. First in our own behavior and then engaging family, peers and organizational networks to build the political will to begin to generate federal response. Now, this brings up a really critical point that I'm not sure we have the time to do this. I don't think we are facing the whole issue of climate change with the kind of emphasis and concern that it deserves. I mentioned at the outset that the mean surface temperature is increasing rapidly. And the expectation was, and the goal was to achieve no greater than a 1.5 degrees centigrade increase by 2050. Well, in 2024, there was already a report that the mean surface temperature had already increased in some places by 1.5 degrees centigrade. So there has to be an urgency to this that I don't think people, are aware of. Youth understand this and youth feel betrayed and hopeless. And I think one of the important characteristics of what we can personally change, in engaging our family and peers, is a way of beginning to generate hope that change can occur. Because we can see it if it's our family and if it's our peers. Another important and critical strategy at the institution and state level is procurement policies. These, I think, are the most powerful tool that we have to change production at the municipal or local level, or at the state level. And we were part of an effort to get the HHS to change their procurement policy for their agencies. And although at the very last minute in the Biden administration, they agreed to do this, that's been superseded now by the changes that Trump has instituted. Nonetheless, this can be a local issue and that's where local change has to occur if we're going to build political will from the ground up. Bill, tell me a little bit more about procurement because a lot of people don't even think about that term. But it turns out that the federal government and local and state governments buy lots of food. How is it that they buy lots of food and how they could have sway over the food environment just by their purchasing decisions? So, let's take schools. Schools are a logical place. They have large contracts with vendors and if they set standards for what those vendors were supplying, like insisted on alternative proteins in at least some of their meal services that would have a big impact on reducing greenhouse gas emissions from school meals. And would have a positive impact on the health of students in those schools. This is known as value-based purchasing. Purchasing of products related to values that have to do with not only greenhouse gases, but also animal husbandry and fair workers' rights, and strategies like that. These are possible. They should be beginning in our universities. And this is an effort that we have underway here at George Washington University. But there are even better examples where universities have used plants as a default option in their cafeterias, which has, shown that when you do that and when you make the plant-based option the only visible choice, people choose it. And, in three universities, Lehigh, Rensselaer at Polytech, and Tulane, when they made plant-based options the only visible option, although you could ask for the alternative, the choices went up to 50 to almost 60 to 80% when the plant-based option was offered. And these were things like a lentil olive and mushroom spaghetti, which has a very low greenhouse gas emission. In fact, the net effect of these choices was a 24% reduction in greenhouse gases on days when the default was offered. These are practical types of initiatives. We need to increase the demand for these options as an alternative to beef. Bill, I like how you're approaching this from kind of the big top level down, but also from the ground up. Because you talk about things that the federal government could do, for example, but also how important individual choices are. And how people can work with their families and friends and have an inspirational effect by changing their own behavior. Those sorts of things make me hopeful. But let me ask, how hopeful are you? Because I'm hearing from you this sort of dire picture that we might be too late, and that the climate change is happening so rapidly and that the social change needed to overcome that is painfully slow. But on the other hand, you're speaking some optimistic things. So how do you feel overall about where this is going? I'm moderately hopeful. And moderately hopeful because I think young people are engaged. And we need to address the hopelessness that many of them feel. They feel betrayed by us. They feel like the adults in this country have let them down and have not focused enough. That's understandable. Particularly now given the distractions of the new administration. And I think we're in a real crisis and things all of a sudden are very fluid in terms of national initiatives. They've been dominated by the Trump administration, but I think that's changing. And I think that the kind of despotism that led to the station of troops in California, in Los Angeles, is a case in point of overreach of the government. The kind of ICE activities really deserve resistance. And all of that, I think, plays into this notion that we're in a fluid time. This is not a time that people are necessarily going to focus on beef consumption. But the fact that all of these climate changes, clearly a major issue at least for those who admit it, means that we need to begin and continue to build the political will for changes in beef consumption as well as changes in transportation policy. I think that actually beef consumption is an easier target then changes in transportation policy, which is driven by the way our communities are constructed. And in many cases, the only way to get from one place to another is by car, which means that we're going to have a continued dependence on fossil fuels. I don't think we can say the same thing about beef consumption because if we institute reductions in beef consumption, I think we can have a very immediate and longer-term impact on greenhouse gas emissions and therefore on climate change. Bio William (Bill) Dietz is the Director of Research and Policy for the Global Food Institute and a Professor in the Department of Exercise and Nutritional Sciences. Dietz is a member of the National Academy of Medicine (formerly the Institute of Medicine) and serves as a consultant to the Roundtable on Obesity Solutions. He also is the Director of the STOP Obesity Alliance at The George Washington University. He served as Director of the The Sumner M. Redstone Global Center for Prevention & Wellness until June 30, 2024. He is Co-Chair of the Washington, DC Department of Health’s Diabesity Committee, a Commissioner on the Washington, DC Office of the State Superintendent of Education’s Healthy Youth & Schools Commission, and Chair of its Subcommittee on Physical Activity. Dietz is also Co-Chair of The Lancet Commission on Obesity.
