Violence in the Brazilian Amazon has increased sharply in the past few decades, unlike violence in the rest of the country. From 2000 to 2019, the homicide rate in the region almost doubled. This pattern has emerged amid growing concerns about the capacity of the state to enforce the rule of law in a region that is larger than the European Union, contains the world’s main tropical forest, and is mostly sparsely populated. The dominant view is that land conflicts and environmental crimes historically associated with the Amazon, such as illegal logging and mining, are what mainly drive local violence. Yet there have been major increases in violence in areas where these illegal activities have not traditionally been prevalent. At the same time, anecdotal evidence suggests that the Amazon basin has become an increasingly important drug-trafficking route for cocaine coming out of the Andean region—which produces almost all the cocaine in the world—and heading to Southern Brazil and Europe.
Our research explores the possibility that the displacement of cocaine trafficking from aerial routes to waterways partly accounts for the recent increase in violence in the more remote areas of the Brazilian Amazon. In the early 2000s, Brazil’s government began implementing a major monitoring system for Amazonian airspace, which led to the adoption of a policy in 2004 that continues to allow the Brazilian Air Force to intercept and force or shoot down suspicious aircraft. Our research presents evidence that this air-interdiction policy displaced cocaine-trafficking routes to the network of rivers in the Amazon, increasing violence on the ground.
Our analysis focuses on municipalities located in the western portion of the Amazon. This area is closer to the Andean border and constitutes a natural river pathway for moving cocaine from producing countries to Manaus, the only major international transportation hub in the upper Amazon basin. In addition, the Western Amazon is distant from large urban centers and highways and has historically been somewhat protected from traditional environmental crimes and property rights disputes associated with deforestation and violence in the Eastern Amazon. Finally, our analysis focuses on municipalities with fewer than 100,000 inhabitants to avoid the idiosyncratic nature of violence in large urban centers. Of the 277 municipalities in the Western Amazon, only 8 have more than 100,000 inhabitants.
The air-interdiction policy increased the probability of detecting and intercepting aerial cocaine trafficking. This made aerial cocaine trafficking costlier, so traffickers shifted at least some cocaine trafficking to the ground. Fuel consumption by small airplanes fell in the western portion of the Amazon, and traffickers began using boats. Unlike airplanes, boats cross many cities and take a substantial amount of time to reach their destination, requiring support along the way for fuel, food, and protection. This exposed many more communities to drugs and drug-trafficking organizations, leading local populations to become more involved in the business. Cocaine seizures and overdose deaths increased in this region after the adoption of the policy.
Our research finds that the air-interdiction policy increased violence in Western Amazonian municipalities by displacing cocaine trafficking to river routes. The responsiveness of local homicides along river routes to cocaine production in the Andean region increased significantly after the adoption of the policy. Specifically, about 1,430 homicides that occurred between 2005 and 2020 can be attributed to the displacement of cocaine trafficking caused by the air-interdiction policy. This figure represents 27 percent of the total number of homicides in municipalities along river routes during that period. Alternatively, the policy increased the homicide rate by 5.4 per 100,000 people in municipalities next to river routes compared with what would have happened if the policy had not been implemented.
Most of these new homicides involved male victims aged 20 years or older and, among this group, were caused by firearms outside the home. Drug trafficking in the region was highly fragmented during most of the period we analyzed, involving multiple small criminal groups and local populations. This lack of large, hegemonic, organized cartels exacerbated the violence. Additionally, our research finds no evidence that the effect on homicides stemmed from changes in local income, other socioeconomic conditions, or increased enforcement by the police. Furthermore, the policy did not significantly affect local gross domestic product per capita or deaths due to common diseases, suicide, or traffic accidents.
Our findings show that criminal groups can be highly responsive. Faced with stricter enforcement, they may adapt to new technologies in ways that produce different social implications. A systemic view of crime enforcement that considers these responses and their socioeconomic consequences is therefore essential to designing public security policies.
Note
This research brief is based on Leila Pereira et al., “Landing on Water: Air Interdiction, Drug-Trafficking Displacement, and Violence in the Brazilian Amazon,” IZA – Institute of Labor Economics Discussion Paper no. 17425, October 2024.