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Climate change and agriculture: air, water, and soil

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Climate change is making conditions worse for certain crops, while improving productivity for others. SciLine’s next media briefing will cover the myriad ways agricultural production is being affected—and may soon be even further—by climate-driven shifts in air quality, including changing carbon dioxide and ozone levels; water quality and quantity; and soil health. Three scientists will make brief presentations and then take reporter questions on the record. 

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ELENA RENKEN: Hello, and welcome to SciLine’s media briefing on climate change and agriculture: air, water and soil. I’m SciLine’s manager of journalism projects, Elena Renken. For those of you not familiar with us, SciLine is a philanthropically-funded, editorially-independent and completely free service for journalists and for scientists, based at the nonprofit American Association for the Advancement of Science. Our mission here is to make it easier for reporters, like you, to get more scientifically validated evidence into your news stories. And that means not just new stories explicitly about science, but any story that can be strengthened with some science. And if you ask us, that’s just about any story you can think of. Among other things, we offer a free expert matching service that connects you to scientists who are both deeply knowledgeable in their fields, and excellent communicators, all on your deadline. Just go to, and click “I need an expert”. And while you’re there, you can see our other resources for reporters. Now, a couple of quick logistical details before we start. We have three panelists here today, who will make short presentations of five to seven minutes each. Before we open things up for Q&A. To submit your questions, during or after those presentations, hover over the bottom of the Zoom window, select Q&A, and enter your name news outlet, and question. If you want to pose your question to a specific panelist, be sure to note that. A full video recording of this briefing should be available on our website later today or tomorrow, and a timestamped transcript will be posted within a couple of days. If you’d like a raw copy of the recording as soon as possible, today, please submit a request with your name and email in the Q&A box, and we’ll send you a link to the video today. You can also use that same Q&A box to alert SciLine staff have any technical difficulties you might have here.

All right. I’m not going to give full introductions to our speakers. Their bios are on the SciLine website. I’ll just say that we’ll hear first from Dr. Courtney Leisner, who will discuss how climate change affects plants through the air and atmosphere. Next, we’ll hear from Dr. Mallika Nocco, and we’ll focus on how climate change influences water quantity and quality, and how that impacts agriculture. Third, we’ll hear from Dr. Michelle Wander, who will cover how climate change affects agriculture via soil quality. Over to you Dr. Leisner.

Climate change and agriculture: air and atmosphere


COURTNEY LEISNER: Hello, thank you for the introduction. Let me share my screen. All right, hello! I’m going to talk about climate change and agriculture. As many of us know, the levels of greenhouse gases in the atmosphere are rising. And this is due to human inputs and direct impacts on emissions of greenhouse gases, like carbon dioxide and methane. And because of the actions of those greenhouse gases, we’ve experienced significant global warming. Now, in this thermometer image, you can see that we’re approaching about a 1.5 degrees Celsius increase in temperature, and this is all relative to preindustrial times, or 1850 to 1900. Now, 1.5 is considered this essential tipping point, where we might see significant impacts on ecosystem services, or agriculture in a way where it might be hard for us to maintain the same level of agricultural productivity. Now, there’s still some differences in how we see temperature changes over the entire globe. In this image here, we can see that looking at the annual hottest day of temperature change, in the mid latitudes, you do see some high increases in temperature, however, there is definite differences when you look across the globe of where things might get hotter than others. This is also seen when we look at precipitation and soil moisture. So in this image here, we look at annual mean total soil moisture change. And if we look across the different images of our globe, and looking at different warming scenarios, we can see that in areas where it’s wet, it’s going to continue to get wetter, and areas where it’s dry, it’s going to continue to get drier.

And you can really imagine how that might impact climate change—how climate change my impact agricultural productivity because of what types of crops we grow in different areas of the world.

So let’s look at how that food production impacts by climate change. And I want to focus your attention just at the top image here. This is an example of food production impacts on maize or corn yields under three different warming scenarios. Now, this is not only just impacts of elevated temperature, but how we might look at impacts of precipitation, or elevated CO2 enhancement on growth on food production. And as you can see, especially in the more later mid to end century projected warming scenarios, especially in the United States, for example, we have potentially significant decreases in food production. However, the picture is a little less clear when we think about nutrient content. So recent work, especially work done about 10 years ago in 2014 from Samuel Myers’ group, found that when plants are grown under elevated CO2, they actually have a decrease in seed nutrient content. And this was seen in crops such as soybean and rice. However, in crops like maize or corn, we did not see this nutrient decrease. It was also unclear how elevated temperature might impact that relationship with CO2 and seed nutrient content, so this is an active area of research that a lot of scientists are working on.

Now, if we look specifically at instances of climate change impacts on agricultural production in the U.S., there is a lot of growing evidence that we will have reduced agricultural production across different regions of the United States. This is due to not only elevated temperature, but also thinking about frequency and duration of drought. Also, elevated temperature can impact the incidence of pests or crop diseases, and that will also increase due to climate change. And so here, what I’m showing is the Plant Hardiness Zone. This is just for the Southwest United States. And on the left, we have a historical Plant Hardiness Zone versus a higher scenario, where we have really high emissions for the end of the 21st century. And when we say “Plant Hardiness Zone”, really what we’re talking about is the cold temperature requirements of different crops. And the different heat colors here show the annual average lowest minimum temperature. And then you can see here, if we look specifically at California, for example, that by—when we have a lot of greenhouse gases, by the end of the century, we’re going to have really, really high low minimum temperatures. Now, one might think, well, what if we grew crops in areas where the temperature wasn’t as high? So for example, here, if we look at Colorado, we can see that the mean hardiness zone is still pretty low. But if you think about the topography, or the soil in Colorado, that might not necessarily be conducive to growing the same plants or crops there. So it’s something we really need to think about when we when, we think about climate change impacts on agriculture on a national or global scale.

And I, lastly, just wanted to mention that there’s a lot of advancements in developing higher yielding or stress tolerant crops, or climate-resilient crops. So one area that people are really doing a lot of active research and work in is using breeding, or genetic engineering approaches, to help understand the physiology or different genes involved in crops that make them resilient to things like drought or high temperature. And another big area of research is if we look at the crop wild relatives. So crop plants, generally are domesticated or bred from wild ancestors. And if we look at the location of where the wild ancestors are grown, what are the traits they have, what are the genes that they might have that might make them more resilient to elevated temperature, or growing in areas with less water? And can we use those to breed them into our modern elite crop plants that have high yield, and use that as a way to build in this resilience? And finally, if we think about, we hear a lot in the news about artificial intelligence, or how we can use all this strength and computational biology to do really groundbreaking science. We can apply that to agriculture as well, in many different ways, but one of them is crop modeling. So if we can understand different genes or different traits that are very important for plants to survive in really stressful environmental conditions, can we use models to predict how crops might respond under very specific environmental scenarios in the future, and then use that information now, to breed them to be more resilient for the feature. So I hope I ended on a positive note to think about the ways we can really enhance agricultural productivity even in light of a future climate change. So, thank you.


ELENA RENKEN: Thank you so much. And over to you, Dr. Nocco.

Climate change and agriculture: water quantity and quality


MALLIKA NOCCO: Okay, thank you so much. My name is Mallika Nocco. And I’m at the University of Wisconsin-Madison. And my work is primarily in the Midwest, and also the California Central Valley. So thinking about global climate change in water and agriculture. So first of all, I really want to say that global climate change impacts agriculture and the environment by increasing irrigation demand. So I’m sure, hopefully, in this group, that many or many think of global climate change and think of, okay, there’s going to be this increase in temperatures, increases in maximum temperatures. And something that people may not think about as often is it that there’s an increasing aridity that we’re going to see. And this is because a warmer temperature can actually holds more water vapor. So then there’s this term that we use called “the vapor pressure deficit”, and that is the difference between the total amount of water vapor that can be held by the atmosphere at a certain temperature, and the actual amount of water vapor in the air. And this is how we think about aridity from the perspective of crops and plants. So really, with this increasing global climate change impacts to both temperature and aridity, those things are going to act together to increase the evaporative demand of the environment. And this is really the demand for irrigation. So that’s one of the large takeaways from what we’re going to see with an increasing temperature and increasing aridity is there going to, there’s going to be more need for irrigation. And we see that through irrigation expansion in areas where there might not be a need, you see more expansion for irrigation. Because irrigation, in a sense, is a way to remove that risk of not having enough water to produce a crop. This also means that more water is going to be diverted for irrigation. So further stresses on groundwater supplies and surface water resources. I’m just going to use that example from California. In an average year right around this time, the groundwater components of what is used for irrigation is about 30 to 40% of the total irrigation water. But then in what we call “a drought year”, a drier year, it’s a 60 to 70% amount of the total water use for irrigation is coming from groundwater. So there’s this increased stress on this additional resource of groundwater during those drier years. And what we can expect to see is warmer years and drier years, which is going to stress out those water resources a little bit more.

So another impact on climate change—or of climate change on water in agriculture and in the environment is by increasing something that we call “weather whiplash”. And this is a—I know this is a cool-sounding term for something that is pretty unfortunate, which is we are seeing an increase in the intensity and frequency of droughts, and floods, or extreme precipitation events. So we’ll have a drought, we’ll have a drought, and then it’ll be followed by floods or extreme rains. And this is the term, this is what we mean by whiplash is it’s a collision of these unexpected conditions, and this rapid back and forth swing in weather. So what can that mean, in terms of productivity and cycling, like, I just want to give a few examples of that. Flooding, following drought, it can disrupt planting. It can disrupt water transferring cycles, any sort of preseason activities. Drought, obviously, can further stress areas that don’t have irrigation, or areas that have irrigation and limited water resources. And in terms of water quality, an example of something that’s happening, increasingly with weather whiplash, is during the drought of the dry year, you’ll see a collection of nitrogen in a dry droughty soil. It’s a nitrogen-enriched soil, and then you have that really wet flooded—flood conditions following the—the dry year, and that’ll mobilize and move that nitrogen into water resources. So you’ll see issues with drinking water when a lot of nitrogen is pushed through the soil profile. So that’s another kind of environmental impacts associated with increasing weather whiplash.

I want to give one more example related to that increasing weather whiplash. And this is something that we see, especially with our fruit crops or our tree crops, where we rely on them to flower to produce yields, and to produce a fruit crop. And sometimes with the weather whiplash, it can also happen when we see an increased—all of a sudden, there’s increased temperatures followed by decreased temperatures, or vice-versa, there’s a—there’s decreased temperatures followed by increased temperatures, again. And this, sometimes people call this “a false spring” is one of the things that you’ll—the terms you’ll hear associated with this weather whiplash. And when a false spring happens, if you can think of a flowering crop, an example is there’s a false spring in 2012. And there were there was early flowering. All the trees just thought, oh, it’s time to flower. And this—and then there was followed by a freeze, and this really devastated a lot of cherry crops, as an example, in Wisconsin, in our, in our Door County region. So that’s just one example of what this whiplash can do in terms of flowering tree.

So I study irrigated agriculture. And one aspect that’s related with climate is irrigated agriculture can actually change regional climate. And what will happen is we have these large expanses of irrigation, and they can decrease maximum temps and increase minimum temps. And folks, I’ve seen this in the western part of the United States. I’ve demonstrated it in the Midwestern part of the United States. And what we also see is an intensification and increasing of precipitation. So I wanted to mention that because this is something that you may come across as well, but it’s also important to know that this regional cooling effect that can be associated with irrigated agriculture isn’t enough to reverse the impacts of global climate change. And it’s also, oftentimes, a cooling effect that can be fed by the unsustainable use of ground—of groundwater or surface water. So that’s also something to consider. I also wanted to point this out, and I’m happy to answer more questions related to this complicated cartoon that I’m putting up here in the Q&A period. But I just wanted to point out that irrigated agriculture can also intensify and change several different cycles. So we think of it as something that’s changing the water cycle, but you can also change the carbon cycle. So the screen is the carbon cycle, because oftentimes, irrigation is accompanied by intensification. So you can see there’s more plants planted in the irrigated system. It changes the nitrogen cycle, because, oftentimes, the more water that’s pushing through, the more nitrogen that’s required for the intense crop into the groundwater resources.

And finally, as I mentioned, it can change the energy cycle through those changes to regional climate. And yes, happy to talk more about that in the Q&A period. Just a few specific examples. So this is an irrigated system in the Midwestern United States, in Wisconsin in the Central Sands Region. We have a potato crop that’s irrigated. And here, in the Midwest, we get a lot of rain, generally, but the rain doesn’t always fall when we want it, and it doesn’t always fall in the amount that we want. And that’s something that’s becoming increasingly unreliable. So this is the reason, that especially sandy soils, are often irrigated in the Midwest. And the water quality problems that are associated with this are coming from a place of they can have water quantity impacts on lakes and streams that are adjacent to these agricultural regions. In terms of water quality, there can be drinking water issues with nitrate pollution to groundwaters. And I also just wanted to point out that there is a connection with irrigated agriculture, expanding, and also the consumption of energy. And irrigated agriculture can be a significant component of energy usage in agriculture, because it takes energy to pump groundwater as the climate becomes drier and drier. Lastly, I know that we’re moving into soil health, so I wanted to talk a little bit about soil health connections. And this is just some drone imagery from an experiment, our group is working on, where we are trying to understand the cover crop usage of water in these almond systems, because there’s concern about doing something that we think of as a valuable soil health practice, and how much water that’s going to use. So what—there is this connection, and we need to kind to think about water resources for agriculture in a changing climate, how best to use those water resources, and also how best to maintain a healthy soil. And with that, I will transition to the next panelist. Thank you.


ELENA RENKEN: Thank you so much. It’s great to keep in mind how those false springs may affect agriculture throughout the season. And over to you, Dr. Wander.

Climate change and agriculture: soil quality


MICHELLE WANDER: —unmute myself. And I was going to try to be fancy and use a pointer, if I can. So it’s a pleasure to talk to you today about climate change and their impacts on soils and soil health and water. And wanted to start with the basics of soils, soils are interesting, because they take a long time to change. And so in many ways, we focus on their inherent characteristics, which I’ll have you think about as their nature. And right now, we have a lot of interest in figuring out how to manage them in terms of nurture, to mitigate and adapt to climate change. So a lot of the conversation that we’re hearing about soil quality and health is really trying to emphasize this stewardship component in relationship to soil services or ecosystem function. So the yellow box on the right has a list of things, and different framings and presentation—highlight different things. But I think for all of us, in agriculture, we think about this ability to support life and think about that as crop productivity. But of course, this includes other—or other life, biodiversity issues and feedbacks. And so in agriculture, we think about the ability to retain and supply nutrients. We think about—ask soils to sequester and detoxify pollutants. We rely on them for protection of water and air quality through some of the feedbacks that were pointed to today. And this issue of buffering and stress, which we—think we’ve also heard a little bit about, I want to emphasize.

We also think of soils and not all soils are under agricultural production, the sort of widening of appreciation of their contribution to cultural and aesthetic services. But I wanted to really get into this the way we think about soils, and we think about their utility is, is in terms of what they do for us. And we really think often about their resistance and resilience, or ability to recover from stress. So I’ve highlighted some words to attract you to terminology. So this resistance and resilience idea of soils, and us trying to track whether they can withstand and maintain their utility to us is a really important thing that we often characterize them in terms of their physical, chemical and biological properties. Now, the traditional inventories, and soil survey has focused on the inherent properties that are very influenced by the nature or parent material. So the picture on the right is showing you a soil that’s a very thin soil developed on a rocky granitic, or granite parent material. So this is inherently resistant to change that parent material, but it’s a very vulnerable soil.

And then we think about the dynamic properties that change pretty quickly. And those are often the things that we emphasize in terms of soil health, and quality, are the things that would respond to stewardship. So these might be decades, or years, or if we think about, now, like with mass failure with some of these flooded environments, where we have massive erosion, that can happen in days or very quickly. So a lot of the soil health conversations, focus on soils as an opportunity to mitigate climate change. So this is when—we often have thought about this transition from relatively undisturbed or natural lands, into arable lands, that term, agriculturally-used lands, and think about them in agricultural lands that we’ve lost a lot of carbon through their transition in agricultural use. And these sorts of diagrams or arrows. So thinking about it, by adding inputs or changing crop inputs, or carbon inputs, we could actually increase the sequestration. That emphasis and conversation is a big one. I have some resources around that conversation. But I really today want to suggest that we might think more about this adaptation, and just trying to maintain what we have, and prevent loss because some of the changes in climate, in many places and important agricultural systems, are going to have to work very hard to do that, in that challenge. And this is an example why we’ve already heard about increases in rainfall, and the dry getting drier, and the wet getting wetter. So here if you look here on the left, this is a diagram of rainfall intensity, which is one of the ways that we describe the erosive power of rain and a major driver in all of our models, it has now really come out of U.S. efforts and is used globally, this rainfall intensity. So they looked at here, this is for 2015, where you see that red is a less intensive to yellow, and up to the blue. I think they were thinking of water in their color scheme. So the—we have in the Southeast, the more intensive rainfall. So if you look over here on the right, which we’ve already heard the sort of intensification in the wet areas of rainfall, which is going to contribute to increased water erosion. And they did a similar thing where they do different climate scenarios, but sort of, on average, this prediction from the low-end 30 to 66% increase in water-driven erosion is really big. And so that’s quite worrisome if we think about that.

But you might be thinking, well, if you’re in the Midwest, in our, in our prime agricultural lands, that that’s not an issue. But these are pictures from my drive to work right out my driveway, in what I would submit to you as some of the most valuable land in the country, if not the world, less than 2%, very flat lands in the winter. And we see this rainfall, and I think this is, what was the term that was so nice of the—I forget what it was, this terrible, conditions of very—it was freezing, then it got warm, then it rained. We have a lot of runoff. And carries off this residues that are vital for protecting the soil from erosion. And then we see here in a spring picture, same field, this is actually an ephemeral gully, which I think would surprise people to think about this forming on such flat land. And you see this export, which is what erosion does is take the most nutrient-rich, organic matter-rich material, the fine particles, and export them off the field, where they become a real—we take from where they were valuable, and we put them into waterways. And now we have these unexpected ramifications in terms of infrastructure. So I think this is not—we have to do a little bit of a difference in the way we think about not—what soils can do for us, but what we can do for soils, really, to maintain the productive lands that we have.

Switching gears now. And I like this ability to dovetail on the wet getting wetter, and the dry getting drier. And that’s really what we have here, where we have this increasing salinization and desertification. We have another IPCC effort working on this. And you may think that this is a distant problem, but people working in California would be very familiar with this, where they’re doing irrigation and had problems with salinity. So as salt—salt concentrations increases, this is problematic for plant growth. And in climate changes, we’ve already seen, we have changes in rainfall. In the far West, where there’s grass us we would expect it there and rise in temperature. This increases evaporation, and evapotranspiration, that would be the water that moves through the plant, and salts that can be there for a variety of reasons. So in California, where they’re doing a lot of irrigation, and we already heard about them relying on groundwater, that groundwater, a lot of it is saline. And so they have a really difficult time using that. And they alternate sources of groundwater, and that can cause dispersion of the surface soil, and cause terrible crusting problems, for example, for immersion of cotton, where they do a rotation. So over here on the right, this list of climate mitigation practices. For landscape-specific issues, we have lot of tactics we can deploy. But those are at costs and different landscapes with different resources have different potential opportunities. And so again, I take you back to what, for me, is a bit of a surprise where we have had expansion of—I had my little graph here, but where we typically think about it. But in this zone where we have increasing both intensified rain, and then intermittent summer droughts, we have gotten some surprises.

So here you have a picture on the left here of the background is in the Dakotas, from South Dakota. And that that white is not snow. This is salt accumulation. So they have, this is—we have, in the center of the continent, and up into the Canadian Prairies, we were—this is an ancient seafloor that’s got a lot of salt, and with the movement of a lot of crops, and in Minnesota, too, soybean, which is a salt-sensitive crop, real problems being a surprise. And this is a cartoon on the right of how this happens where salts get moved up, and they can concentrate in the picture of the right, upper right corner here in the root zone. And this not only makes it harder for the plants to take up water, it also makes them vulnerable to salt stress and disease. So we have a lot of problems, and we don’t want to follow in Rome’s footsteps. We can—Rome switched from wheat to barley, because barley was much more salt-tolerant. So that’s one tactic. But the truth is, in some of these places that are rain-fed, we don’t have the options for leaching down all the salts on broadly landscapes that they have in some regions, where they have lots of surface water they could import. Which is at cost, which the point’s already been made. So I wanted—


ELENA RENKEN: Dr. Wander, I’m so sorry to interrupt, we want to make sure to leave time for some reporter questions. So if you could wrap up shortly, that would be great.


MICHELLE WANDER: OK. So I think we could look at some case studies. So here, I have some resources, where I would encourage you to consult these articles about. Some of the challenges aren’t just the agronomics. I think the policy, and the economics to lure farmers towards it. And a point that we’ve seen is this is very region and crop-specific, so different things will work in different places, and there’s no silver bullets. So here’s a list of resources around some of the topics I’ve touched on.


What is being done well in press coverage of these issues, and where is there room for improvement?


ELENA RENKEN: Excellent. Thank you so much. And I want to remind reporters, that to submit questions, you can click on the Q&A icon at the bottom of your screen. And while we’re gathering those questions, I’m going to start off by asking each of our panelists to briefly address a question that I hope will be of immediate value to all the reporters here today. What have you seen in the media’s coverage of this topic that has frustrated you as an expert in this area? Or what has impressed you that you’d like to see more of? Dr. Leisner, do you want to start?


COURTNEY LEISNER: Sure. I think a key point is that climate is not weather, and climate is weather over a 30-year period. So I think it’s important for the news to convey that while maybe we experienced a snowfall in July in Washington State, which is a reality that happened, that does not indicate climate change is not real. So again, we’re talking about the change in our global climate over a climatic period, not individual weather month-to-month, or year-to-year. So I think that’s a key point. I hope that the news media can take away.


ELENA RENKEN: Thank you. And Dr. Nocco, do you want to weigh in?


MALLIKA NOCCO: Yeah, absolutely. So something that I just appreciate, in general, is the coverage of news that is related to water and agriculture. I feel like it is covered, and it is in the news. Whenever I’m noticing that there are extreme events happening, and I just appreciate that coverage. In terms of areas that I think could be improved, even though I use the word “drought”, and this builds on what Dr. Leisner just mentioned, the difference between climate and weather. I would love to see more context and coverage around just that there is increasing aridification, and this whiplash, and intense events, and less around, like, oh, it’s drought again, it’s drought again, it’s drought again. And thinking about it, thinking about those things a little bit more clearly would be great. The other thing I would always love to see more coverage on is solutions. So any people and scientists, who are exploring solutions to some of these problems, I always appreciate that type of coverage.


ELENA RENKEN: Great. Thank you. And Dr. Wander?


MICHELLE WANDER: Yeah, I appreciate press covering these complex issues. I think climate change and agricultural interactions are really important. And so maybe that helps attract them to these really difficult issues. And I think that temptation to make things overly simple, and have silver bullets is a temptation. And I think this is something that is done—and also the desire for the just the positive. Right? So it’s my own example of, I think this argument about whether we just emphasized that schools could save us with sequestration, when really, in fact, this is a very complex and nuanced discussions for all of these, and they’re very system-specific. So I think reporters, in some ways, have a better shot at getting through to make these important issues real to people, and motivate action, when they get into the particulars of a place. Because this weather whiplash is people are having particular kinds of challenges and opportunities, and they’re really location specific. So that don’t take this—the oversimplification, if you can avoid it, and thank you for dealing with the complexity.

When it comes to climate change, is the primary risk that certain crops may disappear altogether, or is it more that farmers will need to adjust their agricultural practices?


ELENA RENKEN: Thank you. And a question here from Katherine Bagley at Grist: “When it comes to climate change, is the risk that certain crops will disappear or no longer be able to be grown, or is the risk more that industries and farmers will need to adjust their practices as plants shift to different hardiness zones?”


COURTNEY LEISNER: I could take a jump at that one. I think that there’s not a risk, let’s say, that we’re not going to be able to grow soybeans in the United States or globally. There will be places where we can grow it, or we might still be growing in the Midwest. I think it’s more the latter, where the agronomic inputs that are needed to get enough yield for it to be economical for a farmer might be too high for them to want to grow those crops anymore. And I think this goes really well with Dr. Wander’s point, which is not only do we need to think about climate change at a local or regional scale, because we have these pockets of where intensification happens differently, but also crop-specific. And I think one key thing that is a positive, or a thing to think about in the future, in terms of agricultural responses to climate change, but also sustainability, is diversifying the crops that we grow, or the kinds of things that consumers are open to buying, to making them economically-relevant for a grower. And I think that helps build in resilience, to where maybe a grower can have multiple different things that they’re able to have on their fields that grow in their region now, but that there’s a market for it to be economical for them.

How can reporters assess the scientific validity of proposed solutions to major agricultural challenges driven by climate change?


ELENA RENKEN: Great. Thank you. And another question. This one from Ellyn Lapointe at Business Insider: “I often look for stories on solutions to big problems in agriculture, or the food system, driven by climate change. So for any of our panelists here, do you have advice for vetting those solutions to make sure they’re scientifically sound? And are there any solutions you’ve seen in the news that are not actually viable from your perspective?”


MALLIKA NOCCO: I can tackle the vetting component. I mean, one of the recommendations that I would have is when you see, or come across a solution, to try to find the scientists who have published in the peer-reviewed literature related to that solution. And I think that it is important to—any sort of a solution is going to have different phases, even in the scientific community. So I would try to find a solution where several different people have published about it, as opposed to something where there’s maybe only one group, in one place, that’s publishing about it. So I would try to look for consensus among scientists who are in different places. And if it’s agricultural, like maybe different types of crops, and even trying to find where the disagreements are. Because I think that in science and agricultural science, the disagreements that will start to come up, when people do studies, they help us to see the nuances and understand the conditions, and the locations, and the crops under which a solution could work, and also the conditions under which your solution might not work. And that means that we’ve actually gotten somewhere if we’re starting to understand what their tradeoffs are.


MICHELLE WANDER: Can I jump in on there, too, a little bit?




MICHELLE WANDER: So I think part—my cover crop, or cover crops as a case study is related to this, where I think, often, we want to have a generalization that a practice works. And a lot of our policies actually reinforce this, where we’ll—we will endorse, for example, no-till. And so sometimes our classification, and the way we frame, and describe things lead us into problems because the term, and doesn’t reflect the real complexity, and really what and how it will work. So that’s definitely the case for cover crops. There’s many kinds of cover crops, and different combinations of cover crops would have benefits to different kinds of ecosystem services. So in terms of actually—we have a lot of work to actually do location and system-specific measurement to have some real proof for some of these benefits. Right? So especially if we want to stand up both ecosystem service markets, or policies and programs that get it right, and region specific. And some of these wonderful contrasts, we sort of seen today, between challenges in arid lands and irrigated systems, some of these, we’re going to have totally different issues, and priorities, in both ways we measure it, and challenges that are making them more or less sustainable. And but I would say, I think we—from the scientist’s side, thinking about that. But I think when you’re going to actually look to farmer in the face, I think going things that are really—have some grounding and participatory research, and farmer engagement, or farmer learning networks, and some of, really, on-the-ground to understand barriers for uptake. So cover crops, we know they can do things, and there are some successes, but they’re also failures. Track down the failures, and work with folks to really improve and address some of those things that — you can have policy preventing uptake. You can have agronomies. All kinds of things. So cover crops is a wonderful roadmap for we know things could be great, but we often know if farmers aren’t adopting it, there’s a real—something to really hunt down and listen to.

Is regenerative agriculture a plausible way to reverse the course of climate change?


ELENA RENKEN: Absolutely. Thank you. Another question here from Darrell Anderson from Farm to Fork Radio: “Is regenerative agriculture a plausible way to reverse the course of climate change?”


MICHELLE WANDER: And I guess I’d jump on that in the sense of, I think regenerative ag as a—like sustainable ag, or it’s another term. And I put it in a paper about carbon-centric practices that I didn’t talk about much, but that’s connected to this slide about often we’re really looking at those remedies. So I think that the energy, and the intent of regenerative ag is really in sync with that idea that the carbon systems. And also, I think, this notion that Dr. Leisner—this notion that diversification and groundcover are really important components, dealing with weather and some of the cover cropping challenges. So the question that was asked about integrating covers into perennial systems, there’s some really interesting stuff and feedbacks that are on the frontier. So again, I would say break apart regenerative ag, learn what that particular location is really countering with, and is it—what do they really mean. Right? Because that’s an awfully—it’s an aspirational term. And that’s wonderful, and we need that.


MALLIKA NOCCO: I’ll just jump on this one, too. And I agree with breaking apart the term “regenerative agriculture” and just thinking, okay, what, what does that mean, again, and what place and in what type of context. So, for me, in the work that I’m doing that I’m calling “regenerative agricultural” or “regenerative practices”, we’re looking at stacked management practices. So combining different types of management practices, like cover cropping, or reduced tillage, or different types of soil amendments. And then the other thing, I would add to Dr. Wander’s comments are to also break apart the term “reverse the impacts of climate change”, into more specific functions for a system. So I’ll just share, again, we have a project in California, where we are looking at how these stacked practices, that could be called “regenerative practices” are changing the physical structure of soils, in terms of looking at properties that could contribute to how they store water, looking at properties that can contribute to how they drain water, or water moves through soils. And thinking about how this may improve the function of the systems when the droughts come, or when the floods come, or be able to rebound from those types of events. So that’s what I would say about regenerative agriculture. But again, I do—this made me think of another thing that I appreciate about coverage on these topics. When I meet with prospective young, early career graduate students, or undergraduates, it’s the terms like these that are bringing them to my lab. Right? So I’m getting e-mails from students, who want to become scientists, because they’re reading your coverage and using these terms. So I do think that the terms have value, because they’re getting young people excited about science, and this kind of science. And we want—we want that. So I appreciate that, and I think that there’s power in those terms.

What are your thoughts on farmers working at night to avoid record temperatures, as an adaptation strategy?


ELENA RENKEN: Very good to know. Thank you. And a question from Ana Bueno at KXLN Univision in Houston: “Last year, we saw more farmers working at night to avoid record temperatures, but darkness comes with its own risks. So do you have any thoughts on that plan, whether that would be a bad adaptation plan?”


MICHELLE WANDER: I can’t imagine what it was like to be trying to survive in those temperatures. And I think that this maybe speaks to the earlier question about will we be able to continue to grow things in certain places? And so I think that maybe we will get some technology fixes to help with guidance, and working at night is certainly a possibility. But that has cost to quality of life, if you want to interact with people that are awake in the day. But I think it—the question answers itself of, yes, people can do it for a while, but that’s probably not very sustainable in some ways. And—but an example of what we’re grappling with. And so probably certain things will be moved out of the region for that reason, right, and become unsustainable.

Are our national agricultural policies keeping up with the science around climate and agriculture? How could the upcoming farm bill address agriculture’s role in the climate crisis?


ELENA RENKEN: Good to know. Thank you. And a question from Rae Solomon at KUNC radio in northern Colorado: “Are our national agricultural policies keeping up with the science around climate and agriculture? Are there any areas where policy is particularly out of step, or even any ways that the upcoming farm bill could help address agriculture’s relationship with the climate crisis?” Anyone want to take any aspect to that?


COURTNEY LEISNER: Yeah. I think that a lot of governmental policies have very much embraced that climate change is real, and something that we need to be investing in, in all these different facets that we’ve talked about. Agricultural production systems is an umbrella for many different—we have agroforestry, cattle, everything. We have soil. Water. So, yes, I think they’ve done that well. I think one area that maybe is a little out of step, or could use a little more insight from the researchers, who are doing this work, is on how do we incorporate maybe some more of those cutting-edge breeding or genetic engineering approaches to make plants more resilient to climate change? And I think part of that is not only understanding technology, but understanding how do we potentially deregulate these types of technologies, or approaches, in a way where we make this accessible, and economical for the growers to have access to plants that might be more drought or temperature-resilient, for example.


MICHELLE WANDER: I guess I would say we’ll probably all aware of the challenges in politics these days. Right? So The Farm Bill is really interesting, and maybe it’s a two steps forward, three steps back kind of thing. But the response to learning with the cover crops. and policies at the, at the changes in the cover crop insurance, that took out some significant barriers to allow people to have a better shot at retaining their access to crop insurance in some of these weather-stressed years that they did—so they didn’t have an exact planting date. They could just resume and pick up the insurance as soon as they got the main—the insured crop planted. And that happened very quickly in 2019. So that was sort of a good example of a, of a really need, and it was handled very quickly. And then also people figured out how, very cleverly, to distribute monies, not through government agencies, but through volunteer organizations or private sector entities to get cost share out. So I think some of these things in the government, in many years in the foundation for food and agricultural research, if people aren’t familiar with it is sort of running a large experiment with private sector, trying to get a lot of innovations. And they are investing heavily in, for example, and that kind of stuff. So people are interested in policy check out far.




MALLIKA NOCCO: Oh, go ahead.


ELENA RENKEN: No. No, please go ahead.


MALLIKA NOCCO: Oh, I was just going to add. I think, oh, go ahead. No, no, please go ahead. I was just going to add something that I think about sometimes, it’s I do think I’m not a policy expert, but I do appreciate the policies that have led to incentives for farmers and producers to try soil health or soil conservation, and water conservation practices. Something where I think there could be an additional benefit is taking into account how long it takes for some of these practices to actually show demonstrable effects for a grower. Sometimes, the incentive will only last 2 or 3 years. But to use cover cropping as an example, we really want to—want someone to try something like that for about 5 years would be great, to see some of the longer term effects that we would hope to see and impacts to their agroecosystems.

How would you recommend getting this kind of science to farmers accustomed to long-standing farming practices?


ELENA RENKEN: Great. Thank you. One more question here from Elijah de Castro from the Barnwell People-Sentinel in South Carolina: “How would you recommend getting this kind of science to farmers who are used to agricultural practices that haven’t changed in years?”


MALLIKA NOCCO: I can start with this one, I am not sure if folks are familiar with Cooperative Extension in the land grant university system. My position is actually funded, in part—in part or majority by Cooperative Extension. So I would call myself—I’m an assistant professor and extension specialist for the state of Wisconsin. And those of us who are extension professionals have partnerships and relationships with growers to try to build these relationships, and get them scientifically-based information that would support some of these practices that we’re talking about in behavioral changes. So that’s one area of the land grant system that is committed to this type of work, that I think it would be great for everyone here to be aware of.

Could you provide examples of drought-tolerant crops that have been developed or are currently in use?


ELENA RENKEN: Definitely. Thank you. And then we had a question specifically for Dr. Leisner: “You mentioned stress-tolerant crops, can you give any examples of drought-tolerant crops that have already been developed or are already being used?”


COURTNEY LEISNER: Sure. So I don’t remember which large company came out, but I know there was recently in the last five or so years, they came out with a drought-tolerant corn line. Obviously, the information regarding which gene, or genes, involved is not publicly-available. But they found that for corn, specifically, it maintained adequate yield under drought-like conditions. So I know that that was a more recent release of drought-tolerant corn that has come out.

How sustainable is the almond industry going to be under various climate scenarios?


ELENA RENKEN: Excellent. Thank you. And next: “I was wondering, we know that the almond industry uses a lot of water, how sustainable is that going to be under various climate scenarios, or what’s being done about this?”


MALLIKA NOCCO: So I can speak to what’s being done about this. And I am partnering with the Almond Board of California as a part of a large group of scientists. We are called “The Tree Remote Sensing of Evapotranspiration Research Group”, or “T-REX project. And you can Google that and check out our website. And the goal here, and this is an industry-driven goal. And I will, as I think stated in my conflict of interest form, I have received funding to be a part of this research project. But one of the goals of it is to try to reduce the water that is used to produce almonds, and try to figure out many different ways to hack that. Right? So one of the ways that we’re trying to do it is by improving irrigation management, and in trying to build better tools for almond growers to manage water, with as much precision as possible. So using precision irrigation. Also, with using as good of scheduling as possible, as they can, in terms of the timing of application of water. We are also working on ensuring that their systems are functioning optimally, with micro irrigation systems, which is what’s typically used in almond orchards. There’s this issue of trying to make sure that they’re uniformly applying water, and making sure that there are no like leaks or clogs in the system. We call this checking their distribution uniformity. And just by ensuring that the systems are optimal, there actually could be a significant water savings across the Central Valley. So we’re trying to work on all of these issues. But what I will say is that these issues are all related to trying to still produce an almond crop that uses the least amount of water possible. And I think whether or not almonds should be grown, and whether there should be almonds produced in the Central Valley. And they’re always going to require water to be produced, and they are always going to use more, or have a greater evapotranspiration than the precipitation that’s falling in that region. And so those are policy questions, I think, that those who are living in the state of California, and are water users, and are involved in their government, I think that’s for those communities to decide as well as policymakers.

What common misunderstandings do consumers have about agriculture and climate change, and what important insights about farming could benefit consumers?


ELENA RENKEN: Thank you. This question comes to us from Crystal Nay from Modern Ag Media: “Do any of you see a lot of misunderstanding on the consumer end regarding agriculture and climate change? And is there anything you think consumers should know about farming that they might not?”


MICHELLE WANDER: I guess in this, this is maybe a Herculean task for education. I think—I think we’re going to see in the conversation, people try to quantify and compare tradeoffs in utility of different ecosystem services provided. So we’ve probably had a lot of people at least expose a little bit to greenhouse gas emissions, and the calculations that are combining energy use and emissions, not only of balance of carbon dioxide, but other heat trapping gases, right, methane and nitrous oxide. And some of these are—we’re going to have some real surprises as we get better at understanding differences. And these are interested—things in terms of the hydrology, changes in soils, feedbacks and coincidence of—it sounds really gory and complicated. But in the end, we’re probably going to have real differences in just like that lifecycle analysis and budgeting for energy, carbon and greenhouse gases, we’re doing that for water. So people will talk about green water, blue water, embodied water in an expert—we’re doing all these kinds of accountings. And I think a lot of industry is trying to do that in their triple bottom Line Reporting. And we have rules and protocols. And some of this is going to be like a horrible football game, because it’s going to pick winners and losers. And the assumptions and the accounting systems can get really complicated. And you can present your data in a way, very sincerely But the way that you choose to put a numerator and a denominator, it can look—make this system We’re seeing that. And so for the public to there. And the key way this is going to happen, or not happen, will be educators in the press corps, to help them stay calm, when things are contested. And for scientists to try to both educate. And it may be asking the public a lot to follow these things that might bore them to tears, but they’re really important.

So if we’re—to get it right, for example, California almonds, and when and where, how to diversify them, and the true costs in a reasonable average. So again, for the—the weather, the meaningful weather average, and way to support farmers adopting practices that take long-term commitment. Right? These are—these are fundamentally different than applying a fertilizer or a single-moment decision. These are system-level transformations. Right? They lured the establishment of nut crops in California with long term subsidies. Right? So we can do it. But we have to know what direction to run. And to run in the right direction, we’re going to have to look at tradeoffs and ecosystem services, and go there. And we know that’s going to be hard, because it’s going to have pushback from people who will be getting job opportunities or losing job opportunities. So it’s going to be hard. And so the press and education around this is going to be really important.


COURTNEY LEISNER: And if there’s time, I also just wanted to add, I think that there’s this great discussion of weather whiplash, right, that we, that we have all been discussing. And it just makes me think about, so I work on blueberries. It’s part of the research. We do we look at how blueberries, as an example of a perennial crop, like almonds, respond to climate change, because we know much less about perennial crops and their responses to climate change. However, I also have very young children, and they love to eat blueberries. And they would like to eat blueberries every day of the year. But we shouldn’t necessarily, as a consumer, expect a farmer in the United States to be giving, it’s not economically-beneficial for them to produce blueberries year-round. So we have to get those from South America, depending on what time of the year it is. And so there’s this idea that we want to go to the grocery store, as a consumer, and get what we want. But there’s the reality of, for example, this weather whiplash, where it gets very warm, plants flower. And then oh, no, there’s a frost; the blueberries are all gone. And how does that impact the farmer, and the strife that they have to go through to deal with these—this unpredictability now, that they are having to handle. And maybe just understand that that’s, that’s their day-to-day challenge. It’s not necessarily this bucolic lifestyle, where they’re not having to have real dollars and cents that are affecting their livelihood, that’s directly impacted by the extreme weather that we’re seeing now with climate change.

What is one key take-home message for reporters covering this topic?


ELENA RENKEN: Very good to remember. And now before our final question, when I’ll ask some of the—for some piteous takeaways from our experts today. I wanted to flag for reporters that as you log off, you’ll get a prompt for a survey that will take under a minute to complete. I know we’re all a little tired of surveys, but your feedback would really help us design briefings that are even more useful to you. Now, for our panelists, I want to end today by asking each of you to offer our reporters a take-home message in about 30 seconds. So if there’s one thing you really want them to remember, as they consider covering this topic, what would it be?


COURTNEY LEISNER: I would say that my takeaway, and I think this has been echoed by all three of us, is that there are really regional-specific impacts of climate change. But I think as reporters, you can really be the voice to understand those in the region that you live, how they will be directly impacted by climate change, and how agriculture, or the crops that are grown in that region, might be better or worse suited under climate change, and what tools and resources are needed to help bring resilience to that—those specific agricultural regions.


ELENA RENKEN: Thank you.


MALLIKA NOCCO: So my takeaway would be that there is going to be an increasing need for water, and for irrigation, to produce crops here in the United States. That water needs to come from somewhere, so there’s going to be stresses on water resources. And that’s going to be groundwater and surface water. And I think, very similarly to Dr. Leisner, trying to understand that interaction between increasing water stress, increasing production, and how that plays out in different communities, is going to be very important, because there’s also these values that the communities have for water. So some communities have strong values around surface waters. Some communities are going to have drinking water challenges. And all of these are going to have interactions with agriculture. And I think it’s important to think of that in a community, or story, or case-based approach.


MICHELLE WANDER: I think that that’s an example of some of the known/knowns is that we are going to have some real stresses on agriculture, and society. And the unknown/unknown is how we’re going to deal with that. Right? And it’s going to be really to work, people are going to have to think about adaptation, and really committing to a long-term vision, and not get frozen in short-term challenges. Right. Somehow we have to move together, and be very compassionate for people who will be—you hate to think of somebody having to farm at night to survive, for example. That was a very vivid question. So I think some of these things are—or changing, taking out our nut crop—nut crops in western. The drought almost took care of that when they stopped irrigation, right, during for a period of time. Some of these things, we know this is coming, and we need to somehow support that. And I think the press is probably one of the most important tools that we have to get people to appreciate that that long-term societal challenge. And it is going to be—come down to location-specific solutions.


ELENA RENKEN: Excellent. I want to thank our panelists for so generously sharing their expertise today, in the interest of enriching the news with scientific evidence. And thank you to reporters, for your commitment to factual scientifically-informed reporting. Reporters, please follow us on Twitter @realsciline, and make sure you’re registered with at to get notified about any upcoming events. Thanks again, and we hope to see you at the next SciLine media briefing.

Dr. Courtney Leisner

Virginia Tech

Dr. Courtney Leisner is an assistant professor in the School of Plant and Environmental Sciences at Virginia Tech. Her research is focused on understanding how we can maintain an adequate and nutritious food supply under portending future climate change. In her research, she uses genomics-enabled plant physiology to understand climate change’s impacts on plant production and nutritional quality. She currently teaches courses within the School of Plant and Environmental Sciences covering topics such as genomics of crop breeding for abiotic stress, plant physiology and fundamentals of plant biology.

Declared interests:


Dr. Mallika Nocco

University of Wisconsin-Madison

Dr. Mallika Nocco is an assistant professor and extension specialist in agricultural water management in the Department of Biological Systems Engineering at University of Wisconsin-Madison. Her expertise is in soil-plant-water relations, irrigation management, and in water productivity. In her role, Dr. Nocco works with growers to navigate the ever-changing terrain of sustainable agricultural practices and to implement water-saving measures that advance production goals. As a cooperative extension scientist, Dr. Nocco collaborates with scientists, growers, policymakers, and water districts to develop irrigation management strategies that balance farm livelihoods and water conservation, with the goal of meeting the growing and changing needs of agricultural communities.

Declared interests:

I have received grant funding from the Almond Board of California, the California Tomato Research Board, the American Viticulture Foundation, and the Wisconsin Potato and Vegetable Association, which are all grower-funded organizations related to agriculture.

Dr. Michelle Wander

University of Illinois Urbana-Champaign

Dr. Michelle Wander is a professor in the College of Agricultural, Consumer and Environmental Sciences at University of Illinois Urbana-Champaign. Her expertise is in agroecology and agricultural sustainability, and her research is on influence of management on soils, organic matter and system performance with an emphasis on nutrient cycling, plant-soil relations, roots and physical protection of organic matter, soil conservation and alternative methods for soil testing. Dr. Wander works with farmers, educators, and policymakers to quantify the benefits of diversified and organic production, precision conservation and woody perennial polycultures, and determine how standards, voluntary marketing, and decision support tools can encourage soil stewardship.

Declared interests:


Dr. Courtney Leisner presentation


Dr. Mallika Nocco presentation


Dr. Michelle Wander presentation