Medellin, Colombia
City population: 2569000
Duration: 2014 – ongoing
Implementation status: Ongoing
Scale: Meso-scale: Regional, metropolitan and urban level, Micro-scale: District/neighbourhood level
Project area: unknown
Type of area: Previous derelict area, Residental
Last updated: March 2022

Medellin is the second-largest city in Colombia. The city used to be one of the most dangerous in the world, as Pablo Escobar founded here the Medellin cartel. After the death of Escobar, the city's homicide rate has decreased by 95% and extreme poverty by 66%, thanks in part to a string of innovative mayors who laid out plans to integrate the poorest and most violent hillside neighbourhoods into the city centre in the valley below. The same innovative mayors realised that Columbia and its cities are very vulnerable to climate change being located in a tropical zone and is influenced by El Niño and the La Niña. In Medellin, the municipality has built upon a tradition of planning to become an urban lab for the construction of public life with the aim of inclusive, peaceful and sustainable development. As such starting in 2008 Medellin began implementing a green strategy whose goal was the creation of a green belt around the city as well as waste control. The intervention discussed in this case is one initiated in 2014 when the municipality carried out planting and reforestation projects for the protection of the eastern slopes of the city. (1,2,3)

View of the city


Nature-based solution

  • Parks and urban forests
  • Large urban parks or forests
  • Pocket parks/neighbourhood green spaces
  • Green corridors and green belts

Key challenges

  • Climate action for adaptation, resilience and mitigation (SDG 13)
  • Climate change adaptation
  • Climate change mitigation
  • Environmental quality
  • Waste management
  • Green space, habitats and biodiversity (SDG 15)
  • Habitat and biodiversity conservation
  • Green space creation and/or management
  • Water management (SDG 6)
  • Flood protection
  • Health and well-being (SDG 3)
  • Creation of opportunities for relaxation and recreation
  • Social justice, cohesion and equity (SDG 10)
  • Social justice and equity
  • Environmental education


Creation of new green areas

Project objectives

Colombia is vulnerable to climate change, it is located in a tropical zone and is influenced by El Niño and La Niña. The city of Medellín is also particularly sensitive to climate change due to climate variability. Since the city is influenced by the Aburrá River and surrounding streams and mountains, it faces risks like landslides and flooding. The goals of this intervention are: 1. To tackle sprawl and lessen natural disasters (the areas of the green belt will be declared nature reserves) 2. To increase the city’s energy efficiency by implementing solar panels in the park 3. To sequester carbon emissions (climate change mitigation through a forest carbon sequestration project, Más Bosques para Medellín, that operates within the voluntary carbon market) 4. To provide citizens with new recreation, education, sport and community meeting facilities 5. To deliver an environmental education program that promotes green practices that contributes to reductions in greenhouse gas emissions

Implementation activities

The intervention is ongoing however the sources identify 3 stages: the design, planning, and the completion of a pilot phase of the project (2012, 2016, 2017). The greenbelt was officially presented as a tool to address several land use and ecological challenges, namely to restrain unregulated growth and sprawl in the hillsides around the city; protect water basins and forests key to the region’s biodiversity; control climate change effects, and reduce risks of landslides during extreme weather events. Through the planning and construction of the Jardín Circunvalar, one of the most delicate interventions that the municipality is facing is the relocation of thousands of residents living on unstable terrain or on the site of greenbelt infrastructure. Relocation efforts are accompanied by programs to educate residents about the risks facing their homes and lives, and to suggest preventative measures that will increase safety. (7)

Climate-focused activities

Climate change adaptation:

  • Implement measures that prevent/manage desertification, soil erosion and landslides

Climate change mitigation:

  • Increase green urban nature for carbon storage (wetlands, tree cover)
  • Improve carbon sequestration through selection of more adaptable species
  • Raise public awareness of behaviours, lifestyle and cultural changes with mitigation potential

Biodiversity conservation or restoration-focused activities

Biodiversity conservation:

  • Protect and enhance urban habitats
  • Preserve and strengthen existing habitats and ecosystems
  • Preserve and strengthen habitat connectivity
  • Protect species
  • Undertake specific measures to protect species
  • Undertake specific measures to protect native species
  • Means for conservation governance
  • Biodiversity offsets

Main beneficiaries

  • Marginalized groups: Low income citizens
  • Young people and children


Management set-up

  • Government-led

Type of initiating organisation

  • Local government/municipality
  • Researchers/university

Participatory approaches/ community involvement

  • Dissemination of information and education
  • Consultation (e.g. workshop, surveys)
  • Joint implementation (e.g. tree planting)

Details on the roles of the organisations involved in the project

This intervention was led by the Municipality of Medellin, and it is part of a bigger strategy of the city to address crime and climate change. The municipality was the initiator of the intervention, helped in the first years by the Nation University of Columbia. Later on, in the implementation stage, the municipality involved the citizens directly affected by an increase in the frequency of extreme rainfall events. Up to 50% of the residents living in “high risk” zones in self-built communities in Medellín are poor rural-to-urban migrants, internally displaced people within Colombia from the decades of the armed conflict plaguing rural areas with guerrillas, paramilitaries, and drug traffickers. (6,7)

Project implemented in response to ...

... an EU policy or strategy? No
... a national policy or strategy? Yes (One of the sources mentions that this type of intervention was targeted by the National Plan of Development (2006-2010) - Law 1151 of 2007 (4) )
... a local policy or strategy? Yes (The intervention was included in the new long-term Land Us Plan of Medellín (1999–2027)which is seen as the result of citizen discussion and agreement and was approved by eighty percent of the City Council. The intervention is also connected to the Municipal Development Plan 2012 - 2015 "Medellín un Hogar para la Vida" which names specifically the green belt as on of its objectives. Prior to this, one of the sources mentions that the project also was impacted by a 2008 municipal strategy called "Cambio Verde", which sought to motivate the community in the separation of waste to achieve an increasingly effective recovery of the recyclable material that is produced, favoring the protection of the environment and the quality of life of the recuperator.(2, 4))


Total cost

More than €4,000,000

Source(s) of funding

  • Public regional budget
  • Public local authority budget

Type of funding

  • Earmarked public budget

Non-financial contribution

Type of non-financial contribution
  • Provision of land
  • Provision of labour
  • Provision of expertise
  • Exchange of services
Who provided the non-financial contribution?
  • Public authorities (e.g. land, utility services)
  • Citizens (e.g. volunteering)

Impacts and Monitoring

Environmental impacts

  • Climate, energy and emissions
  • Enhanced carbon sequestration
  • Environmental quality
  • Improved waste management
  • Improved soil quality
  • Water management and blue areas
  • Improved water quality
  • Increased protection against flooding
  • Green space and habitat
  • Increased green space area
  • Increased number of species present

Economic impacts

  • Increase of jobs
  • Stimulate development in deprived areas

Socio-cultural impacts

  • Safety
  • Increased perception of safety
  • Social justice and cohesion
  • Fair distribution of social, environmental and economic benefits of the NBS project
  • Improved liveability
  • Education
  • Increased support for education and scientific research

Type of reported impacts

Expected impacts, Achieved impacts

Presence of formal monitoring system


Presence of indicators used in reporting


Presence of monitoring/ evaluation reports


Availability of a web-based monitoring tool

No evidence in public records


Photo 1
Photo 2
Information about this nature-based solution was collected as part of the UNA global extension project funded by the British Academy.