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Mercedes Bustamante: Before the water runs out

Biologist from the University of Brasília warns that deforestation in the Cerrado also harms other regions

Diego Bresani

Climate change is making the Cerrado (wooded savanna) hotter and drier. The volume of water in rivers and underground reservoirs is thus decreasing, and even the wettest years are not providing enough rainfall to compensate for the increase in droughts and evaporation over recent years. If the Cerrado dries up, water will also become more scarce in other regions—the rivers that begin in the fields and forests of Midwest Brazil supply eight of the country’s 12 hydrographic basins.

Mercedes Maria da Cunha Bustamante, a biology professor at the University of Brasília (UnB) who studies native vegetation in central Brazil, has been raising awareness of these issues and calling for more action from public authorities and landowners to stop deforestation and fires. As a member of the mitigation working group of the Intergovernmental Panel on Climate Change (IPCC), she also warns that the country is falling behind when it comes to adopting measures capable of mitigating the impacts of rising temperatures and heavy rainfall events expected over the coming decades.

Age 59
Field of expertise
University of Brasília (UnB)
Bachelor’s degree in biology from the State University of Rio de Janeiro (1984), master’s degree in agricultural sciences from the Federal University of Viçosa (1988), and a PhD in geobotany from Trier University, Germany (1993)
Published works
Author of 135 scientific articles and coauthor of 2 books

Born in Santiago, Chile, Bustamante arrived in Rio de Janeiro with her family at the age of 7. She is divorced and has two daughters—one recently graduated in architecture and the other is studying history at the Federal University of Rio de Janeiro (UFRJ). She spoke with Pesquisa FAPESP via videocall in early December. In January, her suggestions for improving environmental protection were backed up by measures announced by the new federal government, which reactivated the Amazon Fund to direct international funding to deforestation initiatives and restored the powers of environmental inspectors to fine rural landowners for environmental infractions. Bustamante also accepted an invitation in early January to become the new head of the Brazilian Federal Agency for Support and Evaluation of Graduate Education (CAPES), where she worked as director of programs and scholarships in 2016.

How would you assess Brazil’s participation in the 27th United Nations Conference on Climate Change (COP27) in Egypt back in November?
It was different. The country was represented on three fronts: officially, which was perhaps the least visible; by civil society, which has been highly organized since 2019 in response to the reduced role played by the previous administration; and by the Amazonia Governors Consortium, a group that understood COP’s importance to the region and organized its own space, which also received a lot of attention. These three fronts expose the disconnect between the former federal government, the states, and the public. The new administration [which took office in January] was welcomed at COP27 with great hope that Brazil will return to climate negotiations as the leader it once was, with the capacity to put together agreements with other countries. Brazil’s participation shows how the climate discussion is being shaped around the world—it is no longer just a matter for governments, it now also involves the engagement of civil society and the private sector. This recent period of dialogue being broken between these groups was very harmful, because there is no way to resolve the issue without everyone being in agreement. The natural approach is to have voices in the federal government leading the process, but since there were none and nature does not function in a vacuum, others occupied that space.

How do you assess the new government’s plans to end deforestation?
It’s good because the world knows what to expect from Brazil now. In December, the European Union (EU) approved a regulatory framework to trace and ban products associated with deforestation, including both primary products, such as wood, soy, cocoa, and meat, and derivatives, such as chocolate, furniture, and leather. We need to see how the rules will be implemented, how the private sector will respond, and how the European community will monitor them, but this is an indication that deforestation is being taken more seriously on the international trade agenda. Those who have not prepared themselves before will now have to figure out how to meet the traceability and transparency requirements. Consumer countries are taking responsibility and becoming more aware that their environmental footprints also cover the countries of origin of the products they consume. Deforestation is a problem with multiple factors and it cannot be solved quickly by any one person. Multiple actions need to be taken. One of them is to signal that from now on, oversight will be more strict and the law must be followed.

Why is signaling this so important?
Changing the discourse itself is important because it could dissuade people thinking of breaking the law. Announcing that you are going to apply the law is a good start, you don’t need to change anything immediately. It’s not enough, of course. The government needs to act on several fronts. It could also track where the money comes from and goes to, because many of these activities are linked to organized crime. The financial system could help discover who finances deforestation and who gains from it. Another approach the government could take is to utilize vacant federal land, which could be designated as community areas or conservation units to prevent encroachment. Processes for demarcating Indigenous lands also need to be restarted—some have been stalled for decades—and inspection and oversight bodies need to be restructured. IBAMA [the Brazilian Institute of the Environment and Renewable Natural Resources] has been highly discredited in recent years. There’s a lot to be done, or redone.

Farmers rarely realize that the level of underground reservoirs determines the flow of rivers

What are your expectations for the coming years in terms of the environment?
I worked for the government twice. From 2011 to 2013, as general coordinator of ecosystem management and director of policies and thematic programs at the MCTI [Ministry of Science, Technology, and Innovation], and in 2016 as director of programs and scholarships at CAPES. On both occasions, I saw that federal civil servants were generally well prepared. The environmental situation we are going to face in the coming years is much more complex than it was 10 or 20 years ago. The world is more complex and Brazil is more divided. It’s going to be an obstacle race, but we have an advantage because of our accumulated experience.

Most of the debate around deforestation is focused on the Amazon. What about the Cerrado?
The Cerrado is heavily deforested to make room for soy fields and cattle ranches. The situation is very concerning because the biome has already lost half of its native vegetation cover. And creating conservation areas in the region is difficult, because the proportion of vacant land is much smaller than in the Amazon. Since most of the land is private, we need to encourage rural landowners and the private sector to protect the Cerrado, and we have so far failed to do so. The priority still seems to be the potential to clear more space for agriculture. But continuing to do this will play against agriculture itself, because the Cerrado is already hotter and drier due to changes in land use and this will only be more accentuated by climate change. The last IPCC report indicates that this region of Central Brazil has already warmed up more than the global average and is going to get warmer still. A November 2022 report by the World Meteorological Organization [WMO] compared rainfall in 2021 with the historical average for the region, showing that the situation in the Central South of Brazil is critical. Rainfall is well below average throughout the area, which corroborates other regional studies indicating that large-scale transformations in the Cerrado are making the local climate hotter and drier and reducing the flow of large rivers.

What is the impact of these phenomena?
Other regions will be impacted too—the rivers that originate here supply eight of the 12 hydrographic regions in Brazil, as well as the Guarani Aquifer, which supplies water to the Midwest, Southeast, and South of Brazil. As the Cerrado dries up, water will also become more scarce in other regions. The IPCC classifies this as an agricultural and ecological drought, when the annual average soil moisture falls below a certain threshold in relation to the base period of 1850–1900. When the uppermost sections of the soil dry out, less water reaches underground reservoirs. If the drought is a little more intense for a number of years, even a very rainy year is not enough to refill these underground reservoirs, and the deficit increases over time.

Do rural producers yet realize that water is decreasing?
They do, but they always have a localized outlook. They say “this year was good, last year… So-so,” and fail to take a long-term perspective. They are primarily concerned with ensuring the next year’s harvest. They don’t realize that the rain in a wet year isn’t enough to recover from shortages in previous years, because replenishing underground reservoirs is a very slow process. Farmers rarely realize that it is the level of these reservoirs that determines the flow of rivers, which are often outside their property or region. The general pattern of water decline only becomes apparent when looking at data from a larger area and longer period. The WMO report, for example, compared current rainfall with the historical average from the last three decades. This is an important message: less groundwater recharge means less surface water. We need to rethink water use and irrigation.

Personal archiveBustamante (left) during fieldwork in the Cerrado area of the Federal DistrictPersonal archive

A study you published in Global Change Biology in September 2022 showed that the average temperature in the Cerrado is increasing and the movement of water in the atmosphere is decreasing.
Yes, in that article we showed an overview of the situation in the Cerrado for the first time. There are regions in the biome where the temperature has already increased more than the average rise. Some of them are expected to get even hotter. This is the case for MaToPiBa [acronym for an area that covers parts of the states of Maranhão, Tocantins, Piauí, and Bahia], where agriculture is advancing into the Cerrado, primarily for soy and maize farming. This is why this EU’s discussion on product traceability is so important for the Cerrado: MaToPiBa alone accounts for 63% of deforestation in the Cerrado in recent years. This situation cannot be sustained in the long term.

Is it possible to recover the recharge capacity of rivers in the Cerrado or are we close to a point of no return?
It’s difficult to tell. The Cerrado is a complex and heterogeneous system composed of a mosaic of grassland, shrubs, and forests. There are 19 different ecoregions, if you include subregional variations. It is also an enormous biome. In the typical Cerrado landscape of open fields, it is more difficult to identify whether the reduction in the number of trees is a natural phenomenon or a result of degradation. This is more easily identifiable in the dense forest areas. If you look at all of the areas in the Cerrado that have been degraded in recent decades, you will see that the majority of land is still used for pasture—and much of this pasture has very low productivity today. These degraded pasture areas could function as reserves for agriculture, or if they are important areas for water recharge, to help recover the native Cerrado. Studies of this biome clearly indicate that there is no single solution due to the diversity of the landscape and the specifics of each area. We have to plan better land occupation and preservation.

What needs to be done to improve planning?
Political will and collaboration with the private sector. It is easy to locate degraded areas on the map that could be used to restore the Cerrado and others that would allow for soy production to be expanded without further deforestation. But someone owns that land, so agreements need to be made. It’s up to the public sector to get these negotiations started. But it’s more difficult to convince landowners when the financial sector is offering loans to people wishing to deforest these areas to make way for crops. It will be important for the scientific community that studies the Cerrado to guide these processes. We already know enough to start planning, but we need a sign that we will have support from the public sector and collaboration from the private sector. At the moment, that’s what’s missing.

Another study of yours, published in the Journal of Applied Ecology last year, identified 16 million hectares of land suitable for agriculture that are important for restoration. What is the resolution?
There is an overlap. We have to get together with everyone involved to discuss how much we want to expand agriculture in Brazil to the detriment of other functions of land use. The way land is used affects water and biodiversity conservation, climate regulation, food and energy production, and the territories of Indigenous peoples and traditional communities. The maintenance of Brazil’s social diversity itself is associated with land use. Territorial planning must not focus on a single vision. The public authorities are responsible for arbitrating and reconciling the various demands. It’s not a simple task. In Brazil, there is enough space in degraded areas alone for agriculture to increase in the coming years as expected, with no further deforestation. I say this based on the maps made by my research group and others: we can maintain or even expand Brazilian agriculture without deforestation.

Fires started in areas that are being cleared can easily spread to native and protected areas

You mean just in the Cerrado?
No, in all Brazilian biomes. Without deforestation in the Cerrado, the Amazon, or any other biome. If we can increase productivity, we could even reduce the rate of agricultural expansion. In the Cerrado, these two processes are occurring simultaneously. Producers should stop clearing new land after a certain limit and instead diversify production. The Forest Code establishes that properties in the Amazon must conserve native vegetation on 80% of their land, known as a legal reserve. The legal reserve is 35% in the transition between the Cerrado and the Amazon, and 20% in the rest of the Cerrado and other biomes. This is the minimum that must legally be preserved. Before authorizing deforestation, the environmental agency should assess the conditions of the watershed where the property is located and should only approve the clearing of vegetation based on the regional perspective, establishing protections above the limit of the law when necessary. In situations where it is only possible to keep 20% of the area as a legal reserve, the environmental agency could help owners plan the layout of the protected areas to connect native vegetation between properties and form ecological corridors, which can have a greater environmental benefit than disjointed areas. It is not possible to continue deforesting 80%. In the MaToPiBa region, for example, it is crucial that we expand protection on rural properties—we are talking about the last large fragment of the Cerrado. The environmental agency needs to show that any increase in the area of preserved native vegetation can have a positive impact on agricultural crops, such as by maintaining populations of pollinating insects and controlling pests. You have to take all of this into account and convince farmers that it pays to preserve the native vegetation. I hate hearing people claim that they will lose money if they conserve the environment. Anyone who thinks that is doing the wrong math, because with conservation, everyone wins.

Do you talk to politicians in Brasília about these issues?
Yes, whenever I can. Especially at public hearings. But I’ve noticed that opportunities for reasoned debate on the major problems facing the country are in decline. Many important decisions in Congress are made overnight, despite many sectors of society not agreeing with the vote. The deterioration in the debate about what kind of Brazil people want over recent years is also the result of denialism, misinformation, and attempts to discredit scientists and science institutions. Politicians don’t need to be scientists, but since they represent Brazilian society, they should be expected to be able to make a distinction between what is science and what is not. While participating in certain discussions I’ve heard things like: “The European countries are demanding something of Brazil that they didn’t even do themselves—they cut down their own forests.” This argument is complete nonsense. Europe cleared its forests 200 years ago and it is now investing in recovering them. The world has changed. We cannot continue to follow nineteenth-century thinking. The notion that Brazil is a country of abundance, of infinite riches with water to give away or sell has already harmed us greatly. It contributed to the intensive exploitation of natural resources, with no thought for the limits or consequences of our actions. We need to focus on the coming decades, when the impact of climate change will be central to the development of so many countries.

You are part of the IPCC’s working group for mitigating climate change. Are we prepared to face the impacts in Brazil?
We could have worked much harder on mitigating greenhouse gas emissions. Our carbon dioxide (CO2) emissions have increased in all sectors because of deforestation, not just in land use and agriculture. We are also lagging behind in terms of adaptation. We need to remember that adaptation initiatives have a limit. Some are called hard limits, such as humankind’s ability to tolerate rising temperatures or rising sea levels. Others are soft limits, which can be resolved by removing barriers, encouraging policies, and improving living conditions. We don’t seem to be concerned with either hard or soft limits.

What research are you currently working on?
In one project I am examining the origin and impact of fires in the Cerrado, in collaboration with colleagues from the Federal University of Minas Gerais [see article “Intense forest fires damage native vegetation” on the Pesquisa FAPESP website]. Fires require a combustible material, favorable climate, and a source of ignition. In the past, they occurred at the end of the dry season and the beginning of the rainy season, when there is more lightning, but now, deforestation is the main cause of fires in the Cerrado. The worst part is that fires started in areas that are being cleared can easily spread to native and protected areas. We have to control legal and illegal burning activities. Over the coming years, the climate will become even more favorable to fires as it gets drier and hotter. In another study, we are monitoring the invasion of wetlands in the Federal District by shrub species. This gives us insight into changes in the water regime in these areas, which are important for water recharge.

We have to train more women to lead major studies. We have to teach more than biology

When did you first visit the Cerrado?
It was soon after I moved to Brasília in 1993, when I was still a visiting professor at UnB. I went on a university bus with a group of botanists to a conference in Corumbá, Mato Grosso. I had just arrived in Brazil after five years in Germany and I was still trying to figure out my place. Making this journey and crossing the Cerrado to the Pantanal was like a gateway to Brazil. But I was first introduced to the biome while I was studying biology in Rio de Janeiro in the early 1980s, when I attended a presentation at the National Museum by a botanist. She showed some slides of flowers from the Cerrado and I was amazed by their beauty. Before then, the only Brazilian ecosystems I had learned about were the “restinga” sandbanks, mangroves, Atlantic Forest, and a little bit of the Amazon.

What was it like doing a PhD in Germany?
I went there on a program created in partnership between DAAD [the German Academic Exchange Service] and CAPES. CAPES paid for the flights and DAAD paid my monthly fees. It was amazing being able to order a reagent and have it arrive the next day; after having done a master’s degree in Brazil, where I sometimes had to buy things with my own money because they never arrived. I remember the first meeting with my advisor, when I had obtained the first results of my research. I showed up with everything in a bit of a mess—she took one look at the jumble of papers on the desk and said: “Come back next week with this sorted, please.” Within two minutes she had sent me away. That was a lesson that stuck with me: never go to a meeting or presentation unprepared, because the other person is giving me their time. When I got back to Brazil, I noticed that a lot. People often arrived late and did not respect the other person’s time. Today I try to combine the two cultures. I don’t require my students to make an appointment with a secretary—I don’t even have one—and I try to be flexible in conversations, but I do say: “Always be well prepared for everything.” I remind my female students that people demand more of women and expect us to have to perform even better than our male peers. Despite recent progress, we are still judged more strictly than men.

You advocated for women in academia long before the issue became a hot topic. Why?
I come from a matriarchal family. All of the women on my mother’s side studied and graduated from university, even my great-aunts. Having examples to follow means a lot. I was born in Santiago, Chile, because my father worked at ECLAC [the Economic Commission for Latin America and the Caribbean], but my family moved to Rio de Janeiro when I was 7 years old. We arrived in the middle of the 1970 World Cup. I did my undergraduate degree in Rio and my master’s degree in Viçosa, Minas Gerais. When it comes to university, Brazil has an advantage over other countries: salary equality. Everyone starts with the same salary. The differences appear later, in the allocation of research funding and scholarships, which are still biased much more towards men than women. In the academic environment, I quickly saw the need to define spaces for women and said: “Look, we are here as equals. We do not always have the right conditions, but we have the right to a voice.” I always tried to maintain a respectful dialogue. I had worked so hard to get there, I couldn’t just say nothing.

How did the discrimination manifest?
In collegiate meetings, there was participatory exclusion. You were there, but your opinion wasn’t as valued as everyone else’s. This is a problem more associated with my generation. Now we are seeing a new generation of young men and women who are more enlightened, capable of recognizing discrimination and making a stand against it. Gradually, we are breaking down these barriers. In ecology—my field—I had seen situations where there is one woman studying alongside five men in the field. I would like to see more women in higher positions and at international bodies. We also need to train more women to lead research networks and major studies, as well as to apply for international funding and participate in international groups. We have to teach much more than biology.