In Medellín, Colombia’s second-largest city, a significant “greening” initiative launched eight years ago is showing fruitful results as it helps reduce temperatures and improve air quality. The initiative has established thirty green corridors covering more than 173 acres, leading to a noticeable decrease in average temperature by 2°C and enhancing the city’s livability.
Daicy, a local vendor who has been selling coffee under the shade of mango trees on Orient Avenue for over three decades, reflects on the transformation. “There’s greenery everywhere now. It’s much nicer to work under these trees. Before, we were burning!” she says. The avenue is now almost fully shaded by nearly 500 plants and trees, significantly altering the environment of this busy roadway.
The greening of Medellín began in 2016 under then-Mayor Federico Gutierrez, who initiated the project in response to alarming levels of air pollution. Mauricio Correa, an environmental engineer at the University of Antioquia, led the selection of suitable plant species, including mango and almond trees known for their resilience and pollution-absorbing capabilities. “Trees and plants capture sunlight and transform it, unlike concrete, which absorbs and releases it as heat,” explains Correa. This transformation has also improved air quality, with levels of fine particles (PM2.5) dropping from around 33 µg/m^3 in 2016 to an average of 23 µg/m^3 today.
While the green zones have made significant impacts, other factors such as Medellín’s sustainable metro system also contribute to these positive outcomes. However, concerns remain about the long-term ability of these corridors to combat global warming. Correa notes that while trees are adapting well, other plant types are struggling. Research continues on how to enhance these green zones, including studying fungi and bacteria that could improve plant resilience and pollution capture.
Medellín’s model is gaining attention across Latin America, inspiring cities like Bogotá, which plans to plant 8,000 trees along Carrera Septima, and São Paulo, which is bolstering its own greening efforts. Even Santiago, Chile, is exploring this method for potential application.
The success of Medellín’s green corridors comes at a critical time as Latin America faces unprecedented heatwaves. Recent events in Mexico, for example, have seen temperatures soaring past 48°C, leading to increased electricity consumption and power outages. Medellín’s approach offers a hopeful example of how urban greening can mitigate some of the impacts of global warming, serving as a replicable model for cities facing similar environmental challenges.