Case study of
#00006 Expand and target urban tree canopy on the hottest, lowest-canopy streets
Medellín, Colombia
#00054
Implementer
Alcaldía de Medellín — Secretaría de Medio Ambiente
Timeline
Since Jan 1, 2016
Location
Description
Launched in 2016 to counter urban heat island effects and severe air pollution in the Aburrá Valley, Medellín built 30+ interconnected 'green corridors' (corredores verdes) along road verges, streams, parks and hillsides, plus vertical gardens on metro stations, bridges and City Hall. The corridors use layered, forest-mimicking planting to cool through shade and evapotranspiration. The program was implemented by the municipal Secretaría de Medio Ambiente with a total budget of ~USD 16.3 million (~USD 6.50 per resident) and ongoing maintenance of ~USD 625,000/year, funded through the municipal budget including participatory budgeting. Green jobs were created specifically for residents displaced by violence, forming the maintenance workforce that sustains the corridors long-term.
Metrics
5Funding
Lessons learned
- At roughly $6.50 per resident total cost, this is one of the most cost-effective municipal cooling interventions documented — useful as a benchmark when making the case to other city governments.
- Reported cooling varies significantly by metric (~2°C city-average vs ~4.5°C at corridor sites vs ~10°C surface temperature); replicators should define which measure they will use before setting targets.
- Employing local residents — including people displaced by violence — as paid gardeners created a durable, community-rooted maintenance base; structuring green jobs into the program budget from the start was key to long-term corridor survival.
Sources
4Documented Jun 9, 2026