“Like Putting a Lid on A Pot”

UN Secretary-General António Guterres issued an urgent call to action this summer: “Scorching conditions have killed 1,300 pilgrims during Haj; shut down tourist attractions in Europe’s sweatbox cities; and closed schools across Asia and Africa – impacting more than 80 million children… The message is clear: the heat is on. Extreme heat is having an extreme impact on people and planet.” 

Nowhere is immune – not even normally temperate cities. So what solutions are out there? We spoke with Carlos Cadena-Gaitán, Associate Professor in Politics and Development at EAFIT University in Medellín to hear how his city high in the Colombian Andes is dealing with the challenge of urban heat. 

OPEC Fund Quarterly: What heat stress challenges are facing your hometown? 

Carlos Cadena-Gaitán: Medellín is known as the City of Eternal Spring, but these days it barely lives up to its name. Over the last decade it’s been changing into a tropical city, in some ways like Cartagena on Colombia’s Caribbean coast. 

We’re now suffering extreme climate variability, pronounced dry seasons and above average temperatures. That’s brought the urban heat island effect to some neighborhoods, along with the inevitable stress and strain on human health. Worse still, data suggests that in 5-10 years’ time many neighborhoods – including poorer, more vulnerable communities – will regularly suffer from extreme heat island effects. 

Heat is only part of the problem, however. Medellín lies 1,500 meters above sea level, high up in the Andes, but is surrounded by even taller mountains. When we have extreme air pollution combined with low winds, it’s like putting a lid on a pot. Pollution churns from car exhausts and factory chimneys but cannot exit the valley. Every year for the last decade we’ve suffered extreme air pollution stress, causing terrible health effects. 

OFQ: What can Medellín teach the world about responding to crises? 

CCG: “Climate governance” is the key term here. For decades we’ve seen various communities work together and push forward urban environmental projects with a long-term perspective. It involves grassroots initiatives following up on governmental issues, combined with active, long-term participation from the private sector and academia. 

It’s a semi-formal network with four nodes – public, private, civil society and academia – providing fertile ground for innovative initiatives such as our green corridors. Things that people said cannot be done, but still we’ve managed against all odds. Remember that in the early 1990s Medellín was a failed city, the most violent place on earth, home to Pablo Escobar and the Medellín cartel; and remember that Colombia endured 50 years of civil war and remains a very unequal society. So if we can do it, anyone can! 

One of our most celebrated projects in Medellín has been our “green corridors” initiative. That was initially funded via international cooperation, but was soon supported by the city government as well. It involves turning some of the main transport arteries into green avenues, so the area separating one lane from the other becomes a little garden. Or in some cases, vast gardens! They quickly turn into lush green forests because we’re in the middle of the tropics and have fertile volcanic soil. 

OFQ: How much water do these gardens and corridors use? How efficient and sustainable are your irrigation systems? 

CCG: We take water for granted in Medellín. It’s such a rich city when it comes to rain patterns and our water basin. City-wide, we have more than 4,000 creeks, all flowing into the Rio Medellín. We haven’t even started a discussion on whether we will have enough water to maintain our gardens and parks. But that does raise an important point about the confluence of green and blue urbanism – green for the environment and blue for water in terms of availability and reservoirs, for human and animal use, as well as for dealing with excess flows during the rainy season. These things need to be understood and planned altogether. 

OFQ: What specific case studies can you share for tackling heat stress and improving the city environment? 

CCG: One example is the massive Parques del Río Medellín project. Starting in 2015, the city converted a stretch of the principal highway, which runs parallel to the Rio Medellín, into a park. The project wanted to reclaim the river and its banks as a public space, after decades of being channeled off as a prisoner of two massive highways. You could call it “depaving” the way! 

What we decided to do was to turn a stretch of this highway, on the west and the east side of the river, into a park. It’s a truly beautiful park and not only for people but for all kinds of animals in celebration of our vast biodiversity. The main section is beside the town hall in the city center. It’s a massive and award-winning project. 

During my tenure as Medellín Transport Commissioner, we also turned the center into a low emission zone, following the example of London and other major cities. The zone is already running in Medellín city center, but the long-run idea is to make a larger protective “hub” for all our green corridors. If all these elements come together, then the future can be very different for Medellín. We’d be able to show specific indicators related to improved air quality and resilience in terms of urban heat island effect stress, as well as disaster risk management. 

OFQ: You mentioned “climate governance” and grassroots participation in policy-making. How does that work in practice? 

CCG: That’s something we’ve had for decades, which allows local communities to decide on what to do with 5 percent of the city budget. It fundamentally empowers communities. There are also incentives for different communities to come together for really big projects. It’s one of the reasons why Medellín is so special, as our people are able to decide on projects that deal with neighborhood level issues. 

Participatory budgeting is not perfect and can be influenced, but what is clear is that people across Medellín are increasingly prioritizing climate and sustainability projects by, in and for their communities. So I’m optimistic that despite its many challenges, Medellín will find a way to adapt – and perhaps even become a model of climate governance. 

Carlos Cadena-Gaitán 

Dr. Carlos Cadena-Gaitán is Associate Professor in Politics and Development at EAFIT University in Medellín, Colombia. He previously served as Transport Commissioner of the city of Medellín from 2020-2021. Prior to that, he worked and consulted for the Inter-American Development Bank, United Nations University and UN-Habitat. A frequent media commentator on climate change and transport planning, he has won several international awards, mainly for his work at “La Ciudad Verde”, a sustainability NGO that he co-founded in 2011.