As the planet’s temperature continues to rise and rates of severe and increment weather increase, city planners in Medellin, Colombia are scrambling to find solutions for families in “high risk” zones of the city.
An estimated 180,000 families live on steep mountain hillsides and jagged ravines susceptible to mudslides and other natural disasters in the event of heavy rainfall.
The Valle de Aburra, which encompasses the city of Medellin and surrounding municipalities of Bello and Itagui, is known as the “city of enternal spring” due to the generally mild weather. But as Colombian researcher Camilo Mora has argued, global climate change will have a disproportionate effect on tropical zones, where fragile ecosystems are largely unaccustomed to seasonal shifts in weather. For Medellin, this is likely to mean a prolonged rainy season with a higher prevalence of torrential downfalls.
“In Medellin you will see extended periods where there is no precipitation and times when there is heavy rainfall,” said professor of environmental studies at the University of Antioquia Julio Cañon. “We are also likely to see an increase in frequency of extreme rainfall events.”
Extended dry periods will make the unstable soil along the steep slopes even more treacherous, predicts Cañon, while intense rainfall will increase the incidence of landslides. The combination of less-resistant soil and heavier-than-usual rainfall cycles will, over the course of various dry and wet cycles, break the valley walls apart.
“The ground around the valley is weak, and during periods of heavy rainfall the water table rises, weakening the resistance structure holding the ground together on the valley walls,” said Juan Pablo Osorio, a geotechnical civil engineering professor at Universidad de Antioquia
Social trends related to the urbanization of Medellin contribute to the potential for disaster.
In 1981, Medellin had 1.3 million residents. By 2013, the city’s population had nearly doubled, to 2.4 million, not including the surrounding areas.
For decades, displaced people have been arriving in the city from conflict-torn rural areas throughout the state of Antioquia, pushing growth in informal settlements that expand outwards and upwards, climbing the mountainous peripheries of Colombia’s second-largest city. Until relatively recently, there was no central organization to this process. Now, Medellin’s urban planners are literally fighting an uphill battle to constrain the city’s growth and mitigate the risk of lost life and property.
Medellin Planning Director Jorge Perez told Colombia Reports, “one of the great problems countries like ours have in the urbanization process, is with high rates of displacement outside of the legal system, [which] makes it so people and communities in precarious conditions decide to occupy, invade or construct on land that is under high risk.”
According to the locally based El Colombiano newspaper, up to 50% of the families living in “high risk” zones of the city are displacement victims who came to the city to avoid the violence brought to the countryside by guerrillas, paramilitaries, and drug traffickers.
Since 1985, Colombia has accumulated between four and five-million internally displaced citizens. Many of these often poor rural farmers flee violence in the countryside to seek refuge in the cities, where they settle in marginalized communities on the outskirts. In Colombia, where the majority of the urban populations settle in valleys rather than on the country’s coasts, that has often meant sprawling vertical settlements rising up the surrounding mountainsides.
In the past, municipal governments have lacked the will power and resources to provide safety for these incoming settlers, both against violent street gangs and risks of natural disaster, creating communities where gangs are the authority and building permits are non-existent.
To protect these communities from natural disaster, Medellin is taking measures to educate the residents of these marginalized neighborhoods about the risks facing their homes and lives, suggesting preventative measures and helping to provide for them whenever possible. In areas where the city has been unable to find viable solutions to the inherent risks, the Medellin government has been working toward building public housing projects to relocate families into safer and more controlled environments, according to Perez.
Poor neighborhoods of the city are not the only zones at risk, either, as subterranean waterways below the city’s wealthy El Poblado neighborhood have contributed to fatal landslides in recent years. Environmental engineer Pablo Aristizabal said in an interview with University of Antioquia student newspaper that even though the informal settlements run a high risk due to their location, the threat is greater in zones such as Comuna 14 or Poblado, where the heavy building projects are constructed on land that is highly unstable.
Furthermore, the competency of city regulators has been called into question, especially after the high-profile collapse of an 11-story building in Poblado due to major structural flaws that should have been prevented by city building codes.
While Medellin’s wealthy have concerns of their own to , geotechnical civil engineer Juan Pablo Osorio argued that the informal neighborhoods are still at a much higher risk during the rainy season due to lack of engineering or any form of zoning oversight, which leads to inadequate structural foundations and poor building placement.
Solution? Metropolitan Green Belt
In an effort to combat unplanned outward expansion, the city has start to institute a “Metropolitan Green Belt” around Medellin, a ring of undeveloped natural space designed to limit territorial growth and prevent the settlement of zones that are not suitable for settlement due to unstable land conditions.
Started by Medellin Mayor Anibal Gaviria in 2011, the Green Belt is projected to cost the city $249 million. Construction will start at an altitude of 5,900 ft and will extend out for 46 miles.
“The green belt will not only protect the high mountain environment around the city where there is extensive natural richness, harmonizing the point of contact between nature and the city, but also [serve as] a strategy to contain urbanization, and prevent its spread into areas of high risk for disasters,” said the city’s director of planning.
According to El Colombiano, families living above the altitude limit will be relocated. This has generated its own controversy, as some have predicted that as many as 230,000 people live in the designated territory, not all of which is considered “high-risk.” In interviews with Colombia Reports, city officials declined to offer relevant statistics, or comment on the relocation issue.
The project, according to the city government, is still under construction.
Medellin: a greener future
A first-class metro and innovative public cable car transit system has brought accessibility to Medellin’s high-altitude neighborhoods. The transport innovations, meanwhile, have earned Medellin a reputation as a model of environmental policies for other cities in Latin America and the developing world.
The city’s new Territorial Organization Plan (POT) will focus on measures to harmonize the city’s relationship with its natural environment through the Green Belt, protecting and planting natural vegetation in the water corridors, promoting development and density in the city’s center, and increasing the the city’s commitment to public and alternative transportation such as bicycling.
Perez said he envisions a city where the city’s spacial limits are set, and further growth in encouraged in an increasingly dense city center.
History has not been easy on Medellin and the future may pose troubles related to climate change that are both unpredictable and outside the city’s ability to control. But as awareness of environmental issues continues to expand, and city leaders take innovative steps to combat historical problems and prevent future ones, the city may just find a working balance to ensure its wellbeing throughout the coming century and beyond.
- Interview with Medellin City Planning Director Jorge Perez
- Interview with professor of environmental studies at the University of Antioquia Julio Cañon
- Interview with geotechnical civil engineering professor at Universidad de Antioquia Juan Pablo Osorio
- Retos del Cinturón Verde Metropolitano en Medellín (El Mundo)
- La obra estrella de Aníbal Gaviria será el Cinturón Verde (El Colombiano)
- 180.000 familias de Medellín viven en zonas de riesgo (RNC)
- Informal Settlements Research ISR
- Un completo mapa de riesgos, fundamental en el nuevo Plan de Ordenamiento Territorial (Medellin City Council)
- El grito de las laderas de Medellín (De la Urbe)
- Cinturon Verde Metropolitano