- Hectare for hectare, wetlands in the Brazilian Cerrado holds six times more carbon than the lowland Amazon, according to the first study to estimate carbon stocks in the biome.
- Researchers also found that these wetlands are less stable than other tropical peatlands, and thus potentially more vulnerable to changes in rainfall and groundwater levels.
- Satellite mapping suggests these wetlands may also cover as much as 16.7 million hectares (41 million acres), or 2% of Brazil’s total landmass, a far greater area than previously thought.
- Researchers say they hope that more accurate estimates of the Cerrado’s carbon storage may help change perceptions of it as an environmentally insignificant “sacrifice biome” suited for industrial agriculture.
Fieldwork in the wet grasslands of the Brazilian Cerrado often means long trudges through head-high reeds, following tapir trails and watching for tick nests or boggy pitfalls. All this is made more difficult when your equipment is not waterproof. So in February 2024, when a thunderstorm broke over Chapada dos Veadeiros, a national park in the northeast of Goiás state, ecologist Larissa Verona and her team sprinted for their truck.
“The rain passed in about 10 minutes, but when we returned, we saw a fire had started right in the middle of the road,” presumably from a lightning strike, she tells Mongabay in a video call. “Oh my god, we need to go,” she recalls thinking. “We don’t want to be here when the fire chief arrives.”
Wildfires have become increasingly more common in the Cerrado, Brazil’s second-biggest biome (after the Amazon), which sprawls across 2 million square kilometers (about 770,000 square miles) and hosts a mix of savannas, grasslands and forested corridors. In the past half-century, some 55% of the Cerrado’s native vegetation has been cleared — largely to support the expansion of industrial monocultures and often with the justification that this biome holds less environmental value than the Amazon Rainforest to the west or the Atlantic Forest to the southeast.
This has resulted in degraded soils and dwindling groundwater. But draining and clearing vegetation from the Cerrado’s peaty, wet grasslands, known locally as veredas and campos úmidos, could also threaten a critical carbon stockpile, according to recent research.
The Cerrado’s wetlands could store up to 20 billion metric tons of carbon dioxide, scientists estimated, using a combination of deep-soil sampling and satellite mapping. That represents six times the amount stored by an equivalent area of lowland Amazon forest, the study states.
These carbon-rich wetlands also cover a much larger swath of the region than previously thought.
“We already knew that they probably store a lot of carbon, because it’s something that people who live and work in the region talk about,” says Verona, who started collecting soil samples for her master’s thesis at the State University of Campinas four years ago and is now a technician at the Cary Institute of Ecosystem Studies in the U.S. “But we realized we didn’t have structured information about how much carbon is there.”
The research joins a growing body of work reevaluating the environmental significance of the Cerrado: as a biodiversity hotspot, water tower for adjacent regions and, now, a carbon stockpile. Despite this, the region’s organic soils remain vulnerable to longer, warmer dry seasons, which are already drawing out more emissions from the Cerrado’s wetlands, the researchers found.
“How can we be this far into the 21st century and still not know about this system and all the carbon it stores?” study co-author Rafael Oliveira, an ecologist at the State University of Campinas, asks Mongabay in a video call. “I think the Cerrado can be another climactic icon, like the Amazon, and this paper is one of the first to highlight this with data.”
Digging deeper
Verona and a field team collected peat from six sites in and around Chapada dos Veadeiros, going as deep as 4 meters (13 feet), further than the research team itself expected was possible, and an early indication that the grasslands held more carbon-rich organic soils than previously recorded. Earlier analysis of carbon stocks in the Cerrado’s grasslands has taken soil from as deep as 1.6 m (5.2 ft), with most research only sampling from the first 20-100 centimeters (8-39 inches) of soil, so Vereda’s study states that, to date, the Cerrado’s carbon stocks could have been underestimated by 55-90%. Their research indicates that the wetlands here match the known carbon richness of peatlands in Indonesia and the Congo Basin.
Lacking exhaustive records of peat across the Cerrado, the researchers used satellite imagery of wet grassland vegetation to predict the extent of these carbon-rich soils. While this was validated at nearly 150 recorded peat sites, the study’s authors say more field testing is needed.
Susan Page, a professor of physical geography at the University of Leicester in the U.K., who specializes in tropical peatlands, says the study offers “several novel insights” into how peaty, carbon-rich soils accumulate, adding she hopes it will spur more research into other tropical wetlands.
“Given that these [Cerrado] carbon stocks were previously unknown and unmapped, they have so far been excluded from national, regional and global peat and organic soil carbon stock estimates and global climate models,” says Page, who wasn’t involved in the study. “Hopefully, the groundbreaking work … will be recognized in future carbon stock assessments whilst also providing the basis for greater protection of these fascinating environments.”
Verona’s research also suggests the Cerrado’s boggy carbon stocks are already vulnerable to temperature rises driven by climate change. Measuring trace gas emissions at wet grassland sites across one year, Verona and a field team found that the Cerrado’s wet grasslands release 70% of their annual emissions during the dry season, peaking in September.
This is far higher than other tropical peatlands with similar carbon density, potentially because grasses are more vulnerable to decomposition than the woody vegetation more common in other tropical peatlands.
As the Cerrado becomes hotter and drier, the researchers say they expect the Cerrado’s peatlands to become increasingly vulnerable to drying, dying and releasing emissions. Together, draining, longer dry spells and more frequent fires “threaten to unlock an old and previously stable carbon pool,” they warn. A longer series of gas sampling would be needed to estimate the extent of these emissions, they add.
An exploited ecosystem
Since the 1970s, successive Brazilian governments have targeted the Cerrado for the “sustainable intensification” of mostly soybean agriculture, incentivized by subsidies for fertilizers and central irrigation. Three-quarters of the Cerrado is now privately owned, compared to roughly a third of the land in the Amazon.
In Fecho de Pasto de Clemente, a traditional Cerrado cattle grazing community in western Bahía state, the local association of small farmers estimates that more than 90% of community-owned land has been taken over by agriculture since the 1970s, mostly where historical deeds have not been recognized by the state. On what land is left, the community has also noticed the impact of nearby agriculture in less productive soil and increasingly sparse wildlife.
“The region where I live used to produce rice, beans, cassava, sugarcane, fruit and coconuts,” says Elizete Carvalho Fagundes Barreto, a farmer, social worker and the association’s financial director. “Agribusiness has suppressed the native vegetation, compressed the soil and drained the springs. Fish are no longer found in the rivers; wild animals have become increasingly rare.”
Barreto describes the study’s findings as “very necessary” and potentially an “important tool for protection” in the region, including via financial structures such as carbon credits. But she stresses that without land ownership, local communities still risk being displaced from the Cerrado in the future. “There are laws for land regularization, but in practice it is still a dream and a struggle to make it happen,” she says.
“It is very frustrating and worrying, because these offensives directly affect the sovereignty and sustainability of our territories and the quality of life of all socio-biodiversity and the balance of the Cerrado biome,” Barreto says.
Agricultural expansion was initially driven in part by a “lack of knowledge” of the Cerrado’s ecological history and value, according to Sandro Dutra e Silva, a professor of environmental history at Goias State University, who moved to the Cerrado in the 1980s as industrial agriculture was taking hold of the region.
When ecologists began to study the Cerrado, they assumed its mosaic of habitats had been created by early settlers deforesting older habitats, says Dutra e Silva, who wasn’t involved in Verona’s study. “In fact,” he says, the Cerrado’s grasslands “existed long before the Amazon, and probably played a role in its creation.
“Still environmentalists are pushing for reforestation — thinking about forests as the most important landscape for planetary environmental health,” he adds. “This paper shows that we need to focus on different landscapes, including those we have historically thought of as ugly.”
Grasslands need protection
This perception of the Cerrado compared to its neighboring forested ecosystems is borne out in current legal protections. Brazil’s Forest Code mandates that private properties in the Amazon must preserve native vegetation across at least 80% of their area; the same rule protects just 20% of private Cerrado land. Verona says she hopes the new study can encourage legislators to increase that proportion, known as the legal reserve.
The study also found that veredas store four times more carbon on average than dry vegetation in the Cerrado. With more accurate mapping, Verona suggests the Forest Code could instead be amended to require landowners to specifically protect the most carbon-rich habitats within a land parcel.
Other legal protections exist, but are practically overlooked. Any seeps where groundwater reaches the surface are automatically protected from development under Brazil’s Native Vegetation Law, though in reality in the Cerrado this is often ignored by IBAMA, the federal environmental agency, according to Oliveira. “We know this is the law, but we’re not applying it,” he says. “We’re turning a blind eye.”
IBAMA didn’t respond to Mongabay’s request for comment.
Even as Verona and Oliveira were waiting for the study to progress through peer review late last year, the state of Mato Grosso passed legislation opening two large regions, the Araguaia and Guaporé river wetlands, for agricultural draining. “That exact region emerged in our paper as an important region for carbon. They claimed the wetlands are not really important. Our findings contradict their arguments,” Oliveira says. Verona adds: “It’s frustrating because [that draining] is happening right now; it’s an ongoing thing.”
Other Cerrado experts suggest it’s not just a lack of knowledge about the Cerrado’s ecosystem functions that continues to drive policy decisions about the biome. Gustavo Oliveira, a political ecologist at Clark University in the U.S., says the paper’s findings are “absolutely important” but not enough on their own to shift political consensus on the Cerrado as a sacrificial biome.
“For some people, carbon stocks might hit the spot and make them pay attention, but we also need to have conversations about broader change,” Oliveira, who wasn’t involved in the study, tells Mongabay. Incremental improvements to local conservation policy also risk “scapegoating” smaller landholders, he says.
“Those changes are important; they’re also not enough. We need to focus on the biggest water grabbers,” Oliveira adds, calling for addressing the system of subsidies and tax incentives that encourage the spread of agriculture through the Cerrado.
Banner image: Veredas and campos úmidos are both names for wetlands within Brazil’s Cerrado biome, but the former are distinguished by the presence of palm trees. Image courtesy of Guilherme Alencar.
Citations:
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Verona, L. S., Zanne, A. E., Trumbore, S., Bernardino, P. N., Alencar, G. M., Andreuccetti, T., … Oliveira, R. S. (2026). Vast, overlooked peat, and organic soils in Brazil’s Cerrado: Carbon storage, dynamics, and stability. New Phytologist. doi:10.1111/nph.71027
Hofmann, G. S., Weber, E. J., Bastazini, V. A., Rossatto, D. R., Franco, A. C., Granada, C. E., … Pereira, M. J. (2025). Climate change in the Brazilian Cerrado: A looming threat to terrestrial biodiversity. WIREs Climate Change, 16(5). doi:10.1002/wcc.70022
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Machado, R. B., & Aguiar, L. M. (2023). Could you spare an acre for conservation? Science, 380(6642), 238-239. doi:10.1126/science.adh1840
Bassani, A., Pilon, N. A., Peixoto, F. P., Mattos, C. R., Silveira, F. A., Cunha, L. S., & Oliveira, R. S. (2025). Legally protected, practically overlooked: The neglect of diffuse seeps in the conservation of Cerrado non-floodplain wetlands. Perspectives in Ecology and Conservation, 23(3), 151-156. doi:10.1016/j.pecon.2025.06.001
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