In this episode, we sit down with Professor Meredith Niles to explore how climate-friendly agriculture—from methane-reducing rice irrigation to no-till farming—is actually a quiet powerhouse for public health. While traditional environmental messaging has hit a wall, shifting the narrative to human health benefits (like keeping heavy metals out of baby food and clearing our air) might be the key to finally getting farmers, consumers and policymakers on board. It’s time to take off the carbon goggles and look at the health potential of sustainable farming.

How do we combat climate change? For most people, the obvious answer is: create more renewable energy or switch from gas to electric cars. But the agriculture industry actually has a large role to play.   

About 17% of the world's greenhouse gases come from farming. Everything from cow burps to fertilizer create the pollutants that are warming our planet.

Meredith Niles has been working at the intersection of food and climate change for decades. She’s a professor at Brown University, and her lab tries to find ways to help farmers reduce those emissions, by adopting more sustainable farming practices.

[00:01:17] Megan: This is Meredith. She says the good news is that there are lots of techniques farmers can use to reduce their farm’s climate impact. The bad news is that farmers are not adopting these practices very fast. Mostly because environmental concerns just don't seem to move the needle for that many people.

[00:01:50] Megan: And a similar thing happens for consumers. People like you and me, making decisions at the grocery store.

But, the evidence really shows on the consumer side, only about 4% of US consumers actually purchase something for its environmental and sustainability footprint.

[00:02:34] Megan: It's run its course. We're kind of stuck.

[00:02:36] Megan: But lately, Meredith has reached a realization—in this effort to make agriculture more sustainable, maybe we should talk a little less about climate change and a little more about public health.

[00:02:56] Megan: It turns out that lots of the sustainable practices that make agriculture better for the environment can also bring public health benefits. And right now, health concerns seem to be on people’s minds. Water quality and air quality are getting more attention and food safety and nutrition has become a major concern for Americans, especially in the Make America Healthy Again movement.

So how can farmers tackle environmental sustainability and public health at the same time? To answer that, we have to take a little climate science detour and explain why the farming industry creates so many greenhouse gas emissions in the first place.

But cows aren't the only source of greenhouse gases.

[00:04:16] Megan: Meredith says, rice is typically grown in fields that have been flooded with water. But when these fields are under the water, microbes in the soil actually produce methane, just like the cows.

But when we look at the greenhouse gas profile for the U.S., it's largely production from nitrogen fertilizers, soil management, and then also some of the emissions from animal agriculture.

[00:04:57] Meredith: So farmers generally, especially larger farmers who use tractors, they often will have a plow on the back and cultivate, plow up the land, smooth it out, before they plant something.

[00:05:18] Meredith: But you don't necessarily have to do that. There are other ways that you can manage your soil without tilling. So no-till or reduced till will just do a very small sort of slit in the soil, for example, and insert the seeds through that small slit.

Or you can do what's called direct drilling, where you can actually literally just drill the seed into the soil, and all of that is an attempt to keep those nitrous oxide emissions in the soil, right?

[00:05:56] Meredith: One of these practices that's being promoted for environmental benefits is what's called alternate wetting and drying. And so instead of just flood irrigating the rice and leaving it flooded, you actually do what it says: you alternate dry and wet the rice, and that reduces on average about 50% of the methane emissions from rice.

[00:06:22] Meredith: Exactly, so because it's not in that anaerobic water condition, the methane's not being generated as much.

[00:06:34] Megan: Things like seaweed or something like that?

[00:06:55] Megan: You can even store cow manure in different ways, so instead of creating emissions, you can capture them and turn it into energy.

But again, we're asking sort of individual small businesses to take on the cost of a lot of these and that can be really challenging, especially in tumultuous farming economies, right? You know, the last five to ten years, if you're a farmer, it's ups and it's downs, and it's highs and it's lows. And if you're in the international market, you're dealing with tariffs or you're not dealing with tariffs, you know, things are changing all the time.

[00:07:52] Meredith: So we've seen, for example, no-till and reduced tillage, it's implemented on about fifty to sixty percent of U.S. row crop agriculture at this point. That's great.

[00:08:15] Meredith: So I'll give you, like, a really tangible example.

[00:08:22] Meredith: It also reduces heavy metal content in the rice. Lead, arsenic, cadmium, other things that are really not great for human health.Those things naturally occur in soils, and some crops uptake those heavy metals more readily.

And so this is actually really important, I think, from a human health standpoint, especially because rice is one of those first foods that we feed babies. And we know that heavy metal content for babies is not a good thing for long-term development.

So this is a great example where we've been trying to promote climate-smart rice. There's no problem with that. I think that's fantastic. But we should also talk about this practice for its potential to both reduce emissions for human health and also potentially improve the heavy metal content that's in rice as well.

So Meredith's idea isn't about coming up with new sustainable practices, it's about changing the way we talk about, and market, the practices that already exist.

So from my perspective, we should be talking about both, and I think the public health community has, for a long time, not engaged in agriculture very much at all, or generally painted it as a problem as opposed to recognizing that many of these practices have really tangible, positive public health benefits.

[00:10:37] Meredith: If we can build the evidence base to show that some of these practices can reduce heavy metal content, for example, there might be other more unique ways that would give access to people in more low-income households to those products.

A great example would be the WIC program, the Women, Infants, and Children's program, which serves half of all babies born in this country. And if that program, for example, started to allow for purchasing of rice products that were grown with practices to reduce heavy metal content, now we're talking about greater access and equity for people all across the income spectrum that might want to purchase sustainable food, for example.

[00:11:25] Meredith:These are big ideas. Like, I'm not saying I have the blueprint for exactly how to make this happen, but I'm kind of dreaming big with what I think is possible if we put public health at the forefront of how we think and talk about agriculture.

[00:11:42] Meredith: New funding streams, new ways of people thinking about agriculture and food that isn't just environment. I think that has been the big framing, and I think there's just new ways for us to engage different groups of people to generate the interest, both for consumers and for farmers.

I mean, farmers are living on their land. They're living in these communities. It's not like they're wanting to go out and create environmental pollution or public health impacts when they live in those places. But I think the environmental piece can sometimes just feel really distant and hard to wrap your head around, especially something like climate change.

But, you know, some of these practices reduce water pollution. And water quality for your river, your lake, your groundwater, your drinking water, that's very local. You know, that impacts farming communities and farming families. So I do think also changing the narrative could move the needle on the way we talk to and engage with farmers on this as well.

[00:12:57] Meredith: It's already happened, actually. MAHA is a huge motivator for some of the changes that we're seeing around this in the current Trump administration. So for example, at the end of 2025, the USDA, the U.S. Department of Agriculture, announced a pilot program for regenerative agriculture, which they themselves said in the press release was motivated by the Make America Healthy Again commitment.

There's a strong interest in regenerative agriculture, sustainable agriculture, among the MAHA movement. So that connection is there, and it's actually quite interesting because it's bringing together really different groups of people that haven't always connected on the same issues where historically you might have seen, like, environmental groups really pushing a lot of these practices, now you see MAHA and other, what you might consider more, like, right-leaning, organizations interested in sustainable food and healthy food.

So there's a strong overlap here, and I do think there's huge opportunity with that. I mean, I think it's fantastic that more people care about where their food came from, and are asking questions about where their food came from, and how we're growing it, and how we're producing it, and what's winding up on our kids' plates.

Like, those are all positive things, in my opinion, for public health. And so I think this is an interesting group of people who have not historically been engaged in thinking about agriculture but are very much interested in thinking about agriculture now.

Where I think we have to have a little caution is just to make sure that the movement doesn't get ahead of the science. And so I think we still have a lot of research to do in this space and a lot of science to establish that, in fact, there is a relationship between how we grow the food and the nutrient content, for example, or even the motivation of health as a framing to change behavior. But I think there's great opportunity there, and it's something I'm really interested to explore.

[00:15:10] Meredith: I think it's about talking and framing things in what resonates most with that community. That's true of most things, I would say. Not everyone's gonna be motivated by the same thing that I am. And so if you have a common ground and you can frame something that resonates with that community, but you achieve the same outcome, you know, I think you're still ultimately getting to the same place.

I do tons of research on climate change. I'm still doing research on climate change. I'm not stopping talking about climate change. I'm saying, "Can we add some other things into the mix?" Because it seems like the climate change thing isn't working for everybody, but I still want to achieve the same outcomes.

I mean, I also think the reality is there are different benefits, like multiple benefits, and I think we've actually probably spent too long focusing only on climate.

The singular focus on carbon can sometimes overlook many other important ecosystem services that we also need to be thinking about and prioritizing, like water quality and biodiversity. So I think many people that live in the space I live in have thought about food and ag for a long time, and climate, are welcoming the opportunity to, like, not only have what we would call the carbon goggles on. Like, we need to have the carbon goggles around, but only focusing on climate, and carbon has sometimes been detrimental, I think, to the other environmental and ecosystem services that we have to think about.

[00:16:49] Meredith: Thank you so much. It's been a pleasure.

Humans in Public Health is a monthly podcast brought to you by Brown University School of Public Health. This episode was produced by Nat Hardy and recorded at the podcast studio at CIC Providence.

I'm Megan Hall. Talk to you next month!