August 2nd, 2023
Via C40, a look at Medellin’s green corridor initiative:
Since 2016, Medellín has created 30 ‘Corredores Verdes,’ an interconnected network of greenery across the city. This ambitious initiative adds to and further connects existing green spaces, improves urban biodiversity, reduces the city’s urban heat island effect, soaks up air pollutants, and sequesters a significant amount of carbon dioxide. The Green Corridors project demonstrates how integrated, nature-based policies like widespread urban tree planting can have a far-reaching impact on the local and global environment, as well as significantly improving citizens’ lives and well-being.
This is one of the 100 solutions highlighted in the 2019 edition of Cities100. Now in its fourth year, Cities100 provides recognition for 100 of the boldest projects from cities around the world which are working to address climate change and build a better, greener future. The publication highlights solutions that are replicable and scalable, and which reduce emissions and address the issues that cities face as a result of climate change. Read the Cities100 report, by C40 and Nordic Sustainability, for full details.
As a result of 50 years of rapid urban development, Medellín was experiencing a severe urban heat island effect. To address this phenomenon, the city implemented a three-year ‘greener Medellín for you’ programme, significantly shifting its urban design paradigm. As part of the $16.3 million initiative, 75 citizens hailing from disadvantaged backgrounds were trained by Medellín’s Joaquin Antonio Uribe Botanical Garden to become city gardeners and planting technicians. They have helped to plant 8,800 trees and palms in the 30 corridors that cover 65 hectares. In one of the city’s busier thoroughfares, 596 palms and trees have been planted, as well as more than 90,000 species of lesser plants.
These Green Corridors provide Medellín with a host of ecosystem services: they help to reduce average city temperatures by 2°C, enable carbon uptake via plant growth, capture particulate matter (PM2.5) to improve air quality, and increase urban biodiversity thanks to creation of more wildlife-friendly habitats. These rapid effects demonstrate why nature-based solutions are rapidly increasing in popularity in the field of sustainable urban design.
The Green Corridors project also won the 2019 Ashden Award for Cooling by Nature – watch the video below to hear more about the project from the city’s mayor
Medellín’s advice for other citiesTarget busiest areas for greatest impact
Oriental Avenue, one of the city’s most polluted streets with more than a million people passing through daily, has been targeted as one of the key Green Corridors. The more polluted the area, the greater the potential environmental returns, meaning that including these avenues in the green, interconnected, biodiverse network will reap great rewards for general city life.Make the most of national and local legislation opportunities
Colombian legislation dedicates that a part of cities’ budgets – Participatory Budget – is to be invested in projects citizens which help to select, through a democratic vote. The Green Corridors received a popular mandate though this vote, enabling it to be implemented across the city.Wider benefits
Social: As part of the “A greener Medellín for you” programme, 75 locals from more disadvantaged backgrounds were trained by Medellín’s Joaquin Antonio Uribe Botanical Garden to be city gardeners and planting technicians to plant and maintain the 30 Green Corridors as part of their full-time work.
Health: Three years after the programme’s beginning, Medellín’s urban heat island effect has been reduced by 2°C. In spite of climate change, city officials expect a further decrease of 4-5°C in 28 years’ time. This reverses the previous trend that saw the city’s average temperatures in 2010 a whole 6°C above what should have been Medellín’s average temperature.
Economic: $16.3 million has been invested in this ecosystem services project, which has had a number of positive impacts on citizens’ lives and well-being.
Environmental: A bioclimatic study estimated that in just one corridor, the new vegetation growth would absorb 160,787 kg of CO2 per year for the initial phase of the plants’ lives. The study’s 100-year projection is that around 2,308,505 kg of CO2 would be taken up in the plants’ biomass.
'Black Swans' are highly improbable events that come as a surprise, have major disruptive effects, and that are often rationalized after the fact as if they had been predictable to begin with. In our rapidly warming world, such events are occurring ever more frequently and include wildfires, floods, extreme heat, and drought.
'Green Shoots' is a term used to describe signs of economic recovery or positive data during a downturn. It references a period of growth and recovery, when plants start to show signs of health and life, and, therefore, has been employed as a metaphor for a recovering economy.
It is my hope that Black Swans / Green Shoots will help readers understand both climate-activated risk and opportunity so that you may invest in, advise, or lead organizations in the context of increasing pressures of global urbanization, resource scarcity, and perils relating to climate change. I believe that the tools of business and finance can help individuals, businesses, and global society make informed choices about who and what to protect, and I hope that this blog provides some insight into the policy and private sector tools used to assess investments in resilient reinforcement, response, or recovery.