Colombia: cities weave nature back into their urban fabric

Barranquilla, Colombia lies on the coast of the Caribbean Sea, surrounded by wetlands and tropical forests. While the location is idyllic, it is also perilous: the city of 1.3 million is dangerously exposed to the hurricanes that routinely sweep through the Caribbean. To shield itself from those tempests, Barranquilla has launched an ambitious effort to restore the swamps, waterways and greenspaces that surround the city. Officials hope that work, supported in part by the United Nations Environment Programme (UNEP), will create a buffer against high winds and ocean swells.

Barranquilla is one of several Colombian cities that have, in recent years, re-incorporated nature into their urban fabric. This process, known as ecosystem restoration, is seen as key to adapting to climate change while also helping cities deal with other environmental threats such as nature loss.

"The climate is changing and unless cities adapt, many will face a grim future punctuated by extreme weather events," says Mirey Atallah, the Chief of UNEP's Adaptation and Resilience Branch. "The good news is that cities have a powerful ally in the adaptation process: nature." Urban areas are home to more than half of the global population. And if current trends hold, by 2050, two-thirds of the world's population will live in cities.

Urban areas, though, are coming under increasing pressure from climate change, which in many places is making heatwaves, floods and other disasters more frequent and more severe. This is why 124 mayors and governors from around the world are headed to Cali, Colombia for the upcoming United Nations Biodiversity Conference (COP16) later this month. These leaders will address how urban ecosystem restoration can dampen the impact of climate change while enhancing biodiversity, which is on a steep decline in and around many cities.

At COP16, leaders will also discuss the implementation of the Kunming-Montreal Global Biodiversity Framework, a landmark agreement designed to safeguard and restore nature. It includes a target on biodiversity-inclusive urban planning, encouraging local and national governments to take a whole of society approach and make space for nature to improve the quality of life for citizens and reduce the environmental footprint of cities.

Research from UNEP shows that well-functioning urban ecosystems help lower temperatures, shield residents from disasters, clean water and create natural space for biodiversity to thrive, among a host of other benefits.

Colombian cities are demonstrating how that can be done.

With the support of UNEP's Generation Restoration Cities project, Barranquilla is restoring the polluted Leon Creek, which runs through the heart of the city. Officials are hoping to revive the creek, which had been neglected for two decades, with the help of communities that live along its banks. Barranquilla is also reviving 600 hectares of the Mallorquín swamp, which separates the city from the sea, creating a barrier against storm surges and sea level rise. This effort includes the planting of 250,000 trees, most of them mangroves, and the creation of over 200,000 square metres of public space. As well, Barranquilla is restoring the Gran Malecón along the Magdalena River, a 5km-long structure dotted with greenspaces that was designed to protect against floods.

"Barranquilla has taken on the challenge of restoring its urban ecosystems to improve the quality of life for our people," says Barranquilla mayor Alejandro Char.

Medellín, Colombia's second-largest city, has planted over a thousand trees from 215 native species along the city's roadways and waterways, turning them into green corridors that link natural spaces in the city and contribute to ecosystem resilience. This is helping to improve air quality and reduce temperatures by up to 4°C in some areas, case studies find. That is considered important because cities suffer from what is known as the heat island effect, which makes them warmer than the surrounding countryside.

Cali, host of COP16 and located in the biodiverse Valle del Cauca region, is also implementing nature-based solutions. Crisscrossed by 10 rivers, Cali boasts 12 biodiverse parks and 61 wetlands, home to nearly 600 bird species. One of Cali's key initiatives is the Pact for Wildlife which aims to curb illegal wildlife trafficking and prevent the ownership of exotic species. Other projects include the Wildlife Monitoring Platform, a science-based, open-access system to help authorities control invasive species.

Urban areas have a disproportionate impact on nature and biodiversity loss, and climate change noted a 2021 report from UNEP. They account for at least 60 per cent of planet-warming carbon dioxide emissions and 75 per cent of resource use, while producing about 60 per cent of global waste. Given their outsized impact, urban areas are key to solving many of the world's environmental issues, say observers.

"Cities are both contributors to and victims of environmental degradation, but they are also hubs of innovation and leadership," said UNEP's Atallah. "As we approach COP16, it is imperative that we recognize the critical role cities can play in shaping sustainable future for all."

About Generation Restoration (2023-2025)

The UNEP Generation Restoration project, funded by the German Federal Ministry for Economic Cooperation and Development (BMZ), focuses on scaling up urban ecosystem restoration. Running from 2023 to 2025, UNEP, in collaboration with the UN Decade on Ecosystem Restoration and ICLEI's Global Biodiversity Centre, is working with 23 cities to address key political, technical, and financial challenges. The project has two key components: advocating for public and private investment in ecosystem restoration and job creation through nature-based solutions and Empowering city stakeholders globally to replicate and scale restoration initiatives.  

About the UN Decade on Ecosystem Restoration    

The UN General Assembly has declared 2021-2030 a UN Decade on Ecosystem Restoration. Led by the UN Environment Programme and the Food and Agriculture Organization of the UN, together with the support of partners, it is designed to prevent, halt, and reverse the loss and degradation of ecosystems worldwide. It aims at reviving billions of hectares, covering terrestrial as well as aquatic ecosystems. A global call to action, the UN Decade draws together political support, scientific research, and financial muscle to massively scale up restoration.

The Kunming-Montreal Global Biodiversity Framework

The planet is experiencing a dangerous decline in nature. One million species are threatened with extinction, soil health is declining and water sources are drying up. The Kunming-Montreal Global Biodiversity Framework sets out global targets to halt and reverse nature loss by 2030. It was adopted by world leaders in December 2022. To address the drivers of the nature crisis, UNEP is working with partners to take action in landscapes and seascapes, transform our food systems, and close the finance gap for nature.