Short Wave - Farming Releases Carbon From The Earth's Soil Into The Air. Can We Put It Back?

Episode Date: August 18, 2020

Traditional farming depletes the soil and releases carbon dioxide into the atmosphere. But decades ago, a scientist named Rattan Lal helped start a movement based on the idea that carbon could be put back into the soil — a practice known today as "regenerative agriculture." NPR food and agriculture correspondent Dan Charles explains how it works and why the idea is having a moment. Email the show at [e-mail]. See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy

You're listening to Shortwave from NPR. Hey, everybody. Emily Kwong here with NPR Food and Agriculture correspondent, Dan Charles. Hello, Dan. Hi, Emily. Where are we starting today's episode? Let's start about 50 years ago. In Nigeria, there's a young scientist, fresh out of graduate school. He's just joined an organization, a new one called the International Institute of Tropical Agriculture.

Okay. In Nigeria, it's close to the equator. very tropical climate. His name is Ratan Lau. I met him recently at Ohio State University. That's where he now works. And he was telling me this story about his experience in Nigeria,

where he got an assignment that in hindsight seemed so ambitious, it's flat out ridiculous. I was 25-year-old in charge of a lab and given the mandate of improving quality and quantity of food production in the tropical. Yeah, that is a big mandate for a 25-year-old. Hello, please find a way to make more food and better food for the equatorial region of the earth.

Yeah, just make the world better. Those were challenges which were really, really a big lesson. And he struggled. His central problem was the soil. Oh. It was not like what he'd seen in India where he grew up or Ohio where he'd studied. He would clear a piece of the forest and very very, quickly the most fertile part of the soil, the so-called organic matter, the microbes, the decomposing

roots. It vaporized or just washed away, leaving behind a gravelly dirt as hot and hard as a road. So I would set hard on drying that you cannot even dig until you wet it overnight and come next morning. So the topsoil just vanished. Where did it go? Well, a lot of it was just going into the air as carbon dioxide. And today, thanks in part to Ratan Lowe and a bunch of other scientists, we understand the bigger implications of this, how this is not just bad for growing crops.

It is contributing to global warming, maybe 10, 20% of all greenhouse emissions worldwide. So it sounds like a considerable portion of greenhouse gas emissions is coming from farming. Yeah, it's a real chunk. Yeah. But this is not just a bad news story, Emily. ever since that experience in Nigeria,

Rattan Lowe has been determined to put the carbon back in the ground, restore the soil. And that idea now has a trendy name, regenerative agriculture. Soils like animals can also be endangered because we are abusing them because eventually they are degraded so much,

they are no longer what they were. So today on the show, the story of how Ratan Lahl laid the groundwork for this idea, which could improve agriculture and make a dent in climate change at the same time. You're listening to Shortwave, the Daily Science podcast from NPR. Okay, Dan, so let's dig in. Digging in. Retan Loll was in Nigeria trying to improve agriculture by making the ground more fertile,

running into some big problems. You should know something about Ratan Lauer. He is not the sort of guy who's going to give up. I'm by nature competitive. You're either going to be in the top one, two, three, four, or you're not going to survive. This attitude goes back to his childhood. He grew up poor in India.

His ticket out of the village was a government stipend, a few dollars each month to study at university. And he'd only keep getting that stipend if his grades were in the top five in the class. I was always scared if I'd, did not get good grades. I will not get the stipend. So that was the motivator always.

Fear. It was fear or it was insecurity. That insecurity never really left me even when I was here. He found his way to the U.S. for grad school at Ohio State. Got a Ph.D. in soil science. And so now picking up our stories back in Nigeria, determined to find a find a way to protect the soil in his research plots. And one day, a famous scientist came to visit. Roger Ravelle, one of the pioneers in what we now call climate science. So Rattan Lowe tells

Ravelle about his problems, how this organic matter just keeps disappearing. And Ravelle says, you know, the organic matter is going into the air as carbon dioxide. That's the main greenhouse gas. And he asks Rattan Lauer a question. Can you put it back? Can you put it back? Like put the carbon back into the soil? Mm-hmm. Yep. That simple statement, can you put it back, was my introduction to climate and so on. It stuck with you. It stuck with me. It's still there.

Yeah, it sounds like a question that changed his life. Yeah, it sort of brought together these two worlds. On the one hand, there's farming, which Lao had been focused on. And on the other hand, there's climate science, how we're heating up the globe, releasing greenhouse gases. And, Dan, this problem, we should say that Rattan was trying to solve in Nigeria, where too much carbon escapes when you use land to grow food, it's not a problem specific to one country. Oh, it's happening everywhere. It happens perhaps faster in Nigeria because of the hot climate and the physical structure and chemical makeup of the soil. But the same thing happens everywhere that people are growing crops.

So, you know, just an example, the American Midwest. A couple hundred years ago, when that was all covered with grass, that soil was really rich in carbon. Then settlers arrived. They plowed it all up. And immediately that released carbon dioxide into the air, tons of it from every acre of soil. And today, roughly half of the carbon across the Midwest is gone. Wow. Scientists have actually come up with an estimate for the total amount of carbon released from soil around the world since people started farming.

You want to hear the number? Oh, of course I do. What is it? What's the damage? 130 billion metric tons of carbon. Yeah, I figured it was with a B. Okay, that sounds like a lot. So it is a lot.

I mean, so to put this in perspective, at the current rate that the U.S. is burning fossil fuels, it would take us a quarter century. to release that much carbon dioxide. Okay, so Dan, you were saying that Ratan Lalt, he was working on ways to get that carbon back into the ground. How exactly did he start to do that? Okay. So this idea, what people call carbon sequestration in soil, really became his calling card.

When he came back to Ohio State, you know, to teach in the late 1980s, he was writing articles, giving speeches, describing the soil as this vast global reservoir of carbon. So farmers have been depleting the reservoir, releasing carbon into the air. But he started doing experiments to see if they could also refill that reservoir. This is the West Maltz experiment, and it was set up, I believe, back in 1989. So this is Nal Munna Lowe. He's a PhD student at Ohio State, one of Lowe's students. And he is showing me one of these experiments.

He's going on for 30 years, small squares of soil at the University's Research Farm. So much dedication. 30 years, a 30-year experiment. Gotta keep going to see these long-term phenomena in action. Anyway, so some of the plots have been covered with mulch made of straw every year. Others have stayed bare. And those bare soil plots now contain less than 1% carbon. Versus the carbon content in a plot that receives the maximum amount of mulch is probably upwards of 4%.

Okay, 4% versus 1%. That's a lot, yeah? That's actually a huge difference. If you have that big of a difference in an acre of soil, depending how deep you're measuring, that would be 30 tons of carbon. If you extended that across all American crop land, it would be billions of tons of additional carbon back in the ground. It would cancel out about one year's worth of the country's total fossil fuel burning. And it also makes the soil better. It's more fertile.

It holds more water. It contains more nutrients like nitrogen. Life blood of soil is the organic matter content. You could put that on a t-shirt. And again, when we say organic matter, we're talking about all the decomposed leaves and the roots of grasses, fungi and bacteria, waste, anything that breaks down and nourishes the soil. Right. And scientists are figuring out ways to preserve it and actually build up the amount of organic matter in the soil. The main thing, honestly, is to just stop tilling the soil because that exposes all this organic matter to oxygen

and right away it starts decomposing. So you want to leave the soil covered, ideally with living vegetation. Some fields, maybe you shouldn't even grow crops. You know, let that land be a forest or prairie. You want to leave the soil undisturbed. As soon as that happens, the life-giving process begins to start.

It's a slow process. So it's a slow process, but it's become all of a sudden really trendy, this idea of regenerative agriculture, building up the soil. I've seen TED talks about soil health. Companies are promising to pay farmers to do things that capture carbon. One of these companies, a startup called Indigo Carbon, released a video I was watching. What if I told you that the most promising technology we have to address climate, climate change is growing on 3.6 billion acres across planet Earth. What a seductive question.

I would say tell me more, but really, but really, but really. Yeah. Could regenerative agriculture really make a difference with climate change at the end of the day? Yeah. So I would say your skepticism is well placed. There is a lot of debate about exactly how much carbon these farming practices actually do capture in real life. Ratan Lau, for his part, he has said if the world's farmers all got on board with this, it should be possible to capture about a billion tons of carbon each year.

Others say that is way too optimistic. It doesn't square with what they've observed in the real world. But one thing is undisputed in all of this. When farmers do the things that increase the amount of carbon in their soil, it is also good for the environment in all kinds of ways. You get cleaner water. You get more wildlife on the landscape. And Ratan Lyle says maybe that is the most important result of this whole healthy soils movement. So what I changed, Dan, is that now we think agriculture is a solution not only to food security, but also environment restoration.

Agriculture as a solution, not just to food security, but also environmental restoration. Okay, so basically, right, helping the soil doesn't just make a difference in the bottom line of climate change, but in the health of the environment too. Right, right. So, Ratana's been at this for a few decades, it sounds like, but it also seems that he's got a lot of disciples, a lot of PhD students who are going to keep working on this problem for a long time. Oh, I think so. And really, he was never the only scientist working on this, but he was the one who more than any other, I think, really tried to reach government officials and communicate this big idea to the public. And I think he has succeeded. So is it safe to say we're kind of in the middle of a soil renaissance?

Yeah, let's say so. We're in the middle of a soil renaissance, Emily. Let it be declared today by Dan Charles, NPR Food and Agriculture correspondent. Thank you so much for sharing this story. Thank you. This episode was produced by Brent Bachman, fact-checked by Rebecca Ramirez. and edited by Jeff Brumfield. I'm Emily Kwong.

We're back tomorrow with more shortwave from NPR. Black voters play a crucial role for any Democrat who seeks to win the White House. But some big devise amongst that block and some serious ambivalence could determine who is elected president this November. Listen now on the Code Switch podcast from NPR.