Explore the connections between rainforests, climate, agriculture, and how uncertainty travels from the Amazon canopy to decisions made in the field. The Amazon is often described as a climate engine, influencing rainfall, clouds, and growing seasons far beyond the forest itself. At the same time, rain-fed agricultural systems must operate under increasing pressure from land use change and global climate change, where timing and reliability of rainfall can matter as much as totals. Rather than providing simple answers, the way scientific knowledge moves from flux towers to climate models, and from climate information to real-world decisions, ensures uncertainty is managed rather than eliminated.
*Large-Scale Biosphere-Atmosphere Experiment in Amazonia (LBA): a major international scientific project led by Brazil to understand the Amazon rainforest's role in the global climate, focusing on carbon cycles, land-use change (including deforestation and logging), and water and energy dynamics through remote sensing and ground-based studies. Data collected from flux towers and field sites have been used to assess the impacts of environmental change on regional and global climate.
Transcript
Celso: I'm going to tell how I ended up working in the Amazon when I was a young guy. I did study meteorology in Sao Paulo. I grew up in Sao Paulo, Sao Paulo State, and I studied meteorology. And I learned about the meteorology in the Amazon. It was something interesting to study and think about. That there was this big project starting when I was finishing my bachelor's course, that was the LBA program. This is a large experiment that was planned for the Amazon, and there was people from... the US and Europe also joining in and a lot of the Brazilian researchers. I went to a few months there in the Amazon, and that's where actually I was just graduated, undergraduate, and I was a research assistant. And we started, I started helping build one of these towers.
There was these Dutch guys who went down to the forest with these towers and I helped like building one of them. That's the Jaru Tower. And I didn't know much about the sensors going to be put there. But it was very nice to be in the forest, you know, the first time, like to feel the heat and the view from the towers, like beautiful, beautiful view of the sea of green. I thought, oh, this is a nice thing to do for research. And I offered to help on analyzing the data itself and et cetera. And that's how I started. And there was this project or opening for, at INPE, that's where where I work now at the institution, that they were getting this data and started analyzing the meteorology, the interaction between the...the forest and the meteorology there. I wanted to do some PhD and I applied for a PhD in Wageningen, and I did my PhD there. Then in my PhD, then we actually continued those measurements in Jaru, but also in Manaus. There was also in another tower in Manaus, which is actually now still running until today. So since mid-1999, so more than 25 years now of data collected there. So, and that's more or less how, then I, after that, I lived in Manaus, I finished my PhD and I went to Manaus to spend a year there, and then there was a, I got a job here back in... In some research at this campus, where I am now.
Fabiana: My name is Fabiana. I'm a PhD candidate at Wageningen University. I'm in the, yeah, let's say last stretch of my PhD. My topic is estimating the contribution of forest to. to agriculture in this agricultural frontier in the surroundings of Amazon, in Cerrado and Amazon transition. And I started my PhD 4 years ago. Before that, I used to cover agriculture, but from a different perspective. I used to live in Cuyaba, in Mato Gros, so I used to cover agriculture, agribusiness in general, so visiting farms and and understanding crop systems. And now I will focus on understanding this link between forest, climate and agriculture.
Laurent: So Celso and Fabiana, what does the climate actually look like in the Amazon? And how different is it when you move from the rainforest into the agricultural areas of Rondonia or Mato Grosso? And how does that link to agricultural practice on the ground?
Celso: I'm going to say a bit about the general climate in the The Amazonian region, or it's a tropical rainforest region, so it's there's a lot of rainfall because there's such such a lot of rainfall and a lot of... this beautiful forest in the region. There's a lot of the whole nature, the society lives within nature there, and climate drives like many of the whole life in the region as well. So also, of course, it's also very productive region in terms of farming, and Fabiana can probably also tell a lot about that as well. Because it's such a rich climate, tropical climate is also very productive in terms of it usually has abundance of water available for those crops and for the society there. But the issue now that we are facing, we are, with climate change and with deforestation, some part of the Amazon, a lot of pressure in deforestation, this may be shifting. some of the rainfall regimes, rainfall patterns, and that's sort of a big issue. As you mentioned, there's an issue of the amount of rainfall, some sort of reduction, but also it's very important for farming is the timing of rainfall, whether there's a drier or a longer dry season. That's very important for the production. Fabiana, please go ahead.
Fabiana: Yes, I fully agree with Celso with exactly this, so Deforestation has impacted the forest cover and also the evapotranspiration and the balance of rainfall patterns in this area and is really a high risk of impacting agriculture in a really concerning way. So far, for example, Mato Grosso state, which is the biggest producer of many agricultural commodities such as soybean and corn, and also cotton. Mato Grosso relies heavily on a long rainy season to grow two crops per year. So it's not only a matter of having rainfall, but they need rainfall and a long rainy season enough to grow two crops in the same year. And what we've been seeing in this region is the dry season is getting longer and therefore the rainy season is getting shorter. So we've being more frequent droughts and loss of crop production because of this.
Celso: And it's nice to see, well, you know, there's also a sort of a connection between large-scale pattern, large-scale patterns of rainfall generation, usually because in the tropics they have this large convection in the forest that drives a lot of rainfall. But there's also the effect of local effects, local production. When you change the land surface, like when you clear part of the forest, you also change some of the interactions between the land surface and the atmosphere. And that's so there's a combination of both larger scales and smaller scale effects there.
Fabiana: Yeah, and we can see that is another risk for agriculture because when the deforested patches, they produce more heat from the surface. So it's why when this heat meets humid atmospheric conditions, they provoke, they cause even more rainfall. But when atmospheric condition is more humid, it's in the rainy season. So we see the risk, for example, of having more rain during the rainy season that would be, for example, January or February. And it would be very harmful for crops because it's in this period that Mato Grosso, for example, is harvesting soybeans. And if during the harvest, the crop receives a lot of of rain. It can have delays in the harvesting. It can have problems with the quality of the beans. And at the same time, the same deforested area that causes during the rainy season more rainfall, during the dry season, this heat from the surface don't find a humidity enough to create, to trigger rainfall. And then we have the dry season gets even drier and warm. And then it will affect, for example, the crops that needs more rainfall. That is the second crop, for example, that is cultivated after soybean, which is maize. So in the end of the season of maize, maize has faced a lot of drought risk because the dry season is starting earlier.
Zing: That's really interesting. I'm really enjoying the conversation so far. This question is also perhaps to you, but I mean, Fabiana, you can also add in as well. But I'm just picturing the Amazon forest and perhaps any forest globally acting more as a climate engine. If I'm trying to kind of pick out from my understanding of what you said and by an engine, it helps in redistributing moisture in kind of like the general area where, like Fabiano absolutely mentioned, it kind of It takes some water when it's too much water and then it releases it and which forms strain. So kind of that engine that kind of redistributes moisture in the area and really having this understanding how the Amazon influences climate in this way of exchanging water and energy. kind of, does that relate in some way with the ideas of kind of flying rivers? Is that how that conversation really comes in? And because I know, again, that area is quite scientifically useful and still being actively debated, does that really happen, the idea of kind of Amazon as an agent serving, as a driver for this flying rivers. What do you have to say about that?
Celso: Yeah, that's a very important issue to mention, I think. The whole, yeah, I think the way I see it, is a sort of an engine, a climate engine in the system. I mean, that's a consensus that the Amazon, the whole forest evaporates in general, like in three to four millimeters per day of water. When we scaled this up, we got an evaporation in the forest of like 20 billion tons of water transpired every day. And that's more or less the same amount that's even higher than the discharge of the Amazon River. It's like roughly 10 times the discharge of the volume of the Mississippi River. So it's a lot of water that is put from the forest to the atmosphere. That is transported with the trade winds, with the general circulation, to other regions. That's where this concept of flying rivers come from. You have a regular rivers in the ground, as you know, flowing to the ocean. And in the Amazon, you have a sort of an aerial river going in the atmosphere the other way around, flowing from east to west. And actually, because of the topography in the end, actually, it sort of deviates southwards, and it actually drives a lot of the moisture transport in the atmosphere to this region, to the southern or to the middle of the continent in South America. So part of the moisture in the Mato Grosso area are these most productive area in Brazil, it's actually come from the Amazon. And it's well known where this flying river concept came from. And now the question is, this is not the only mechanism that produces rainfall there. It's part of the mechanism. So there's a lot of the whole generation of the whole circulation of the atmosphere works anyway. But the question is, when we, when you start, when there's a risk of larger scale deforestation in the Amazon, there's a risk that this source of moisture will not disappear, but it will be much lower. And that's a main concern about the future there.
Zing: That's an absolute concern, but that's brilliant. That's really brilliant. Trying to picture water going upwards instead of kind of flowing like we used to see. That's really brilliant. Thanks for sharing that.
Fabiana: And I would like to add, because there's an amount of evapotranspiration from Amazon forests, so as Celso said, 20 billion tons of water per day. When we think about value, this is impossible to value. So I will use a comparison that Tasso Azevedo, director of an institute in Brazil, MapBiomas, tried to value this and he said, yeah, you can imagine so 20 billion tons of water being evaporated every day from Amazon forest, only from Amazon forest, not all the tropical forest, only Amazon forest. And then And you imagine how if you use the electricity capacity available to produce this 20 billion liters of water, you need the whole plants of electricity in the world to work in full capacity. And they would take six months to produce what Amazon produced to evaporate 20 billion tons. And then you, imagine the, how, much is the, is the value of these companies, how much they, having revenue. per year, we are talking about a sector that generates $2 trillion per year. But if they need six months to do what the forest is doing one day, we would say that the forest would value $365 trillion per year. So it's, yeah, almost three times the GDP of the whole planet. So just to say that the value is so unmeasurable. so huge that nothing can do what the forests do for the climate and for the rainfall patterns.
Zing: Interesting.
Laurent: And how did the eddy covariance tower help scientists validate this idea of the rainforest as a massive climate engine for the whole region?
Celso: There's a lot of these findings that we got from studying the forest and sort of deforestation. I think that that's a nice mentioning that that's where like some of these flux towers may also help identify these effects. Like we have been measuring with these flux towers some forest and deforested area, at least one of these legacy of one of these big large program that's called the LBA. The large LBA is the Large Scale Biosphere Atmospheric Experiment in Amazonia. It's a program that started in the late 90s that established a few towers in the Amazon. And so one of these towers was in a reserve in the Rondônia state in a far pristine preserved area. And nearby, there was another tower in a farm. And from this sort of experience, the same climate, we could measure differences between the evaporation in the forest and in the pasture or in this farm cattle ranch area. And also using this data, we also look at, studied the local circulations.
Laurent: So we have this extraordinary system moving 20 billion tons of water every day. What happened when you start cutting it down? Celso, your research looked directly at fragmentation effects.
Celso: When you have this fragmented area, you may have some local circulations generated from the difference between the surfaces, because there's a larger, it's warmer in the pasture or in the farmlands. warmer than in the forest during daytime and then generates sort of local circulation that you might, at some point, you actually start increasing precipitation, increasing rainfall because of this sort of enhanced local circulation. But that's up until a limit, a threshold of deforestation. And then after a larger area deforested, then you get a reduction in rainfall. And that's one of the interesting findings from the LBA program as well. And it's and it's been and it's been interesting to see and then to try to understand how they're actually the limits you need to find thresholds or that there's there at some point it's a large reduction of rainforest also and that will create a bigger bigger problems in the end.
Zing: I'm always very keen to kind of bring down this complex issues to how it affects mankind in terms of day-to-day. And Fabiana, you've mentioned agriculture and what you do in terms of your PhD research. And this question particularly focused on the area around Mato Grosso. So that you've talked about do farmers in this area. I'm just trying to see what you understand of their experience of forest loss on one hand side and global climate change. Do they see this as separate factors or do they understand them as combined source of uncertainty that kind of drives their decisions, their day-to-day decisions? When do we plant soybeans? When do we plant corn? Are we still going to be able to rely on these same crops in the next five years or 10 years? How does this really play in terms of how farmers really understand this based on patterns that they already see? You mentioned earlier and they could see that it's not just when the rain starts, it's also about how much rain falls. So it's all of these things. Do they see them as separate factors? You have, oh, forest has been lost and there is climate change, although they see these two as sort of interacting somewhat to affect how they make decisions.
Fabiana: My perception is that some farmers, they sometimes they surprise me because sometimes they show that they know the role of forest in regulating rainfall patterns. So it's a conversation that I had once with a big farmer and he was very well educated so he could elaborate this role of forest very accurately and But we cannot generalize and say that all the farmers understand this. So I think the farmers deal with risks with technology and they perceive climate issues as coming from many factors, a complexity that he cannot label it was deforestation or it was climate change or it was La Nina or El Nino. And then, but what we can see is that the farmer, I think he gets more conscious as he starts perceiving more changes in climate, impacting their production. And for example, when we just talk about Mato Grosso state, it is a highly productive state. They invest a lot in technology. They have a lot of rainfall. The rainfall has been reduced, but it still is a lot because it's a region that we can find areas with 1200 milliliters per year. And if you consider soybean needs 4, 500 milliliters. Corn, maybe 600 milliliters. So they still have enough rainfall to support these two crops. Of course, they have some issues in the end of the crop, the corn season, because of the dry season is getting longer. But they still have technologies. For example, we see increasing irrigation infrastructure in some areas of Mato Grosso already. they don't think that they are controlling the situation. They mitigate with technology. So, of course, we have, for example, in this state and also in Brazil in general, because Mato Grosso is only one of the states, is the most important producer in Brazil, but is one of the states in an agricultural belt that surrounds Amazon. and the deforestation rates that are going down now in Brazil, but not enough to stop with this damage to ecosystem services. And it is a complex issue. because the farming system and also the farmer groups are so complex. Brazil is so big that we have thousands of farmers with different sizes and backgrounds and education. So it's quite complicated to generalize who to blame in this matter. But I would say that the impact in this area, it has been managed by the farmer with technology. So I think it is how the farmer deal with risk.
Celso: And they have some knowledge of awareness of climate issues just by long practices before, like dealing with the natural El Nino, La Nina years. Sort of they have their own ways of dealing. But now, as Fabiana mentioned, they have access to irrigation and technology. So they sort of do not feel that much in that region.
Laurent: Irrigation in Mato Grosso has intensified massively in recent years. So what does that mean? for groundwater reserves in the long run.
Fabiana: There are, of course, there is the risk of depletion. I have to say that Brazil is quite a lucky counter in terms of water, natural resources, because in this area of Brazil, we have one of the biggest aquifers in the world, that is the aquifer Guarani. And the irrigation in this state, even as has increased, is still small compared to the total, I would say. Less than 5% of the crops in Brazil are irrigated, particularly in this area of Brazil.
Laurent: To wrap up, I would love to ask you both, what does your perfect fieldwork day look like?
Celso: I think that the most of the knowledge, the most important knowledge that we gain from this type, from work, is from collaboration, from the co-production of knowledge with the local people, for example. They also learn, they also know a lot of the life, of how climate, weather patterns affect their lives and how can they best plant or how can they adapt. They will learn from the soils there, what they learn from daily life there. We usually gain a lot of knowledge from this collaboration, from the co-production of knowledge actually. So my view would be a best way to work there would be like to be joining them and understanding with them the challenges and the whole, the processes, the interaction between climate and society there.
Fabiana: I think my perfect field work...Actually, I had a little bit of a perfect field work in my last field work farm, because what I like most is interacting with farmers, with employees and agronomists that are there in the farm, working and producing and trying to make their best. I really like explaining how nature is important and so close for our realities. not as a human beings only, but also as a company or as farming activity. So we all depend on nature and sometimes we live without realizing that. And so we love nature without realizing that we love and we need nature. And I think this kind of knowledge or this kind of interaction I like very much in having with farmers and with collaborators or farmers as well. And so in the last work, we had a meeting and I tried to explain ecosystem services and where in that farm where that people were working, where the ecosystems are providing services, which kind of services, and try to make this be tangible for them. because sometimes we from science, we scientists, we are used to so many technical terms and scientific terms, and we really should make an effort to simplify, to translate these. because it's this, nature is everywhere. And when we start explaining better what exactly nature is and how this impacts our lives, I think we will see people, farmers engaging much more in conserving.
Zing: Completely agree with you there. It's just about taking all this very complex science to now how does this translate to what we see in our day-to-day lives. And I think that to me should be the goal of all scientists, really, beyond and above and beyond all the science and the stats and all the interesting field work that we do. How does this really translate to the day-to-day impact? In this case, how does this impact farmers? You're talking about ecosystem services. And you can, if they can really see your weight, speaking with them in the farm, and you can show them how this service is available. It's very, it becomes very tangible. It's what they can see, it's what they can feel. And I mean, that really brings science alike to them. They would never forget that experience. I'm sure they would feel the impact and they know what you're doing. It's not just some university person coming to do something in our farm. They can see how they are collaborators, going back to what Celso mentioned earlier, how we all are collaborators in this nature and conservation of biodiversity in whatever space that we live. And I think That's a very exciting way to kind of bring this to a wrap.