Words That Fell Trees: Bolsonaro Rhetoric Tied to Surging Amazon Deforestation

When Jair Bolsonaro took office as president of Brazil in 2019, he brought with him a rhetorical style that openly disparaged forest conservation. A new international study led by the University of Bonn, published in The Journal of Politics, now provides rigorous quantitative evidence that those words had measurable consequences on the ground. According to the analysis, the destruction of the Amazon rainforest accelerated considerably in periods when Bolsonaro and his ministers posted messages opposing forest protection on Twitter, suggesting that political rhetoric alone can shift how ordinary people weigh the risks of breaking environmental laws.

The central question the researchers set out to answer is deceptively simple: can political leaders influence whether society complies with legal requirements simply through what they say? Brazil offers an ideal testing ground for this question because it contains the largest share of the Amazon rainforest, the world’s most extensive tropical forest and a critical reservoir of biodiversity and carbon. During the first months of Bolsonaro’s term, he and members of his cabinet repeatedly made derogatory remarks about the protection of this ecosystem, creating a natural experiment in how elite signaling might alter behavior at the forest frontier.

To measure deforestation with precision, the team drew on data from the initiative MapBiomas Alerta, which reviews and validates deforestation alerts from multiple satellite-based sources covering the whole of Brazil. This validation process gives researchers a high-quality record of where and when forest loss actually occurred, rather than relying on raw, unverified alerts. On the other side of the analysis, the researchers examined more than 3,600 Twitter posts that Bolsonaro and his ministers of agriculture, environment, and foreign affairs published in 2019. From this large corpus, they identified 38 posts that signaled a lower enforcement risk for infringements against environmental laws, such as statements criticizing conservation policy or downplaying the likelihood of punishment for illegal clearing.

A crucial insight guiding the study’s design is that political messages are only effective if they are heard. A tweet from the president does not automatically reach a farmer deciding whether to clear a remote plot of land. The researchers therefore estimated the Twitter reach of government messaging across 578 municipalities in the Amazon region. Their proxy for exposure was local Twitter activity: they analyzed how many tweets relating to the topic of forest were posted by citizens in each municipality between 2015 and 2018. The logic is straightforward. The higher the pre-existing Twitter activity in a municipality, the greater the likelihood that relevant tweets from the government would be seen there, whether directly or through secondary diffusion.

That diffusion mechanism, the authors argue, likely extends well beyond the platform itself. As Dr. Gustavo Magalhães de Oliveira, a postdoctoral researcher at the Institute for Food and Resource Economics at the University of Bonn, explains, the team assumes such messages spread through word of mouth. Supporters share them, critics share them, and they are discussed locally until they reach the people who actually make decisions about deforestation. Those decision-makers, whether landholders, speculators, or intermediaries coordinating illegal clearing, view the statements as a political signal about how the federal government will treat environmental crime.

The empirical results show a direct and far-reaching response to that signal. In the regions with the greatest exposure to the government’s messaging, deforestation increased significantly in the months when Bolsonaro and his ministers had published posts opposing forest conservation. Importantly, the researchers checked whether this pattern was an artifact of Twitter alone. It was not. As Oliveira notes, the impacts were not limited to Twitter; the same pattern emerges when the team analyzes other forms of exposure, such as television. This convergence across communication channels strengthens the interpretation that the underlying driver is the political signal itself rather than any quirk of one medium or its user base.

One of the most striking findings concerns what did not change. The researchers found that the government statements had no influence on municipal environmental fines or on deforestation bans. In other words, the actual machinery of enforcement on the ground, the inspections, the penalties, and the legal restrictions, remained the proximate context in which landholders operated. What shifted was something more subtle: expectations. According to Oliveira, the analysis indicates that, as a result of the messages, people changed their expectations of the extent to which they would be prosecuted for breaking the law. The effect is thus not attributable to any changes in the local enforcement of forest conservation laws, but to the perceived risk of punishment, which elite rhetoric could lower even as formal rules stayed on the books.

The study also reveals that the phenomenon appears to be driven by economic incentives rather than political loyalty. If the mechanism were simply that Bolsonaro’s base felt emboldened to follow his lead, the effect should have been strongest in municipalities with high levels of support for the president. The data show no such pattern. Instead, the effect was stronger in areas where agricultural returns are high and where nature conservation policy had restricted deforestation in the past. This makes economic sense: rhetoric lowering the perceived cost of illegal clearing matters most where the potential profits from cleared land are large and where accumulated pressure from conservation rules had created pent-up demand for conversion. Where the economic payoff is small, even a permissive political climate does not move the needle.

The magnitudes involved are substantial. The researchers estimate that, in 2019 alone, between 190 and 1,700 square kilometers of forest fell victim to the statements by the Bolsonaro government. The upper bound of that range, nearly 1,700 square kilometers, is almost double the area of Berlin, a comparison that underscores how a handful of social media posts from senior officials can translate into landscape-scale environmental damage. It is worth emphasizing that this estimate is additional to the deforestation driven by the broader weakening of Brazil’s environmental authorities during Bolsonaro’s term, which the study treats as a separate channel. Even setting aside institutional erosion, the perception of a low risk of punishment was itself a relevant driver of forest loss.

Beyond its immediate findings for Brazil, the study carries a broader warning about the power of political language. It provides evidence of how influential words can be when they come from people holding great political power, and it is quite possible that the effect extends beyond forest conservation and the context of the Brazilian Amazon. Wherever compliance with law depends partly on citizens’ beliefs about enforcement, leaders who signal tolerance for rule-breaking may erode that compliance without changing a single regulation. The research was a collaboration between the University of Bonn, the University of Texas at Dallas in the United States, and Wageningen University in the Netherlands, funded by the Bonn SDG Fellowship Program, the German Federal Ministry of Food and Agriculture, the German Research Foundation as part of the German Excellence Strategy, and the EU program Horizon. For scientists and policymakers alike, the message is sobering: in the digital age, the pen, and the tweet, can be mightier than the chainsaw, and protecting forests may require defending not only institutions but the credibility of the rules themselves.

Subject of Research: The effect of political rhetoric on Amazon deforestation and environmental law compliance in Brazil

Article Title: How Bolsonaro’s statements destroyed the rainforest

Article References: How Bolsonaro’s statements destroyed the rainforest. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: Amazon rainforest, deforestation, Jair Bolsonaro, political rhetoric, environmental enforcement, Brazil, Twitter, The Journal of Politics, University of Bonn, MapBiomas Alerta, deterrence, land use