Densifying and recycling the city: a social, ecological and economic necessity for UN-Habitat

During a speech at the MIPIM international real estate fair in Cannes, southern France, Brazilian Anacláudia Rossbach, Executive Director of UN-Habitat, emphasized the need to further develop approaches to densification and urban recycling. She elaborates on these challenges and outlines potential solutions in an interview with AFP.

Question: Why is it so important to increase urban density and recycle existing buildings?

Reply : "From an environmental perspective, if we don't increase the density of our cities, if we don't optimize the spaces we already have that are vacant or underutilized to meet housing needs, we're going to have to continue sprawling. And cities have already sprawled more than necessary; we're growing more in area than in population. By putting pressure on natural environments, you make cities and populations more vulnerable to climate events."

From a social perspective, we know that urban sprawl generates fragmentation. A high-income household will be able to get around by car, pay for gas, and so on. But not necessarily those with lower incomes. We have numerous examples of low-income communities living in segregated, separate, and marginalized conditions, cut off from access to employment, education, and everything else that cities have to offer. This is not sustainable from a social point of view.

And from an economic standpoint, sprawling cities incur higher costs because they require more infrastructure, which is more expensive for the city. Several studies show that the most sprawling cities tend to collect less revenue but spend more, so it's a bad deal. Broadly speaking, sprawling cities are not efficient; they are not productive.

Question: The population is often reluctant to accept urban densification; how can we make this type of urban planning acceptable?

Reply : "I believe the only way forward is through participation, dialogue, and governance. Society needs to understand the threats we face. This means sharing technical information transparently about what happens if we don't increase density, the cost to society, and all the aspects we've just discussed. This is a conversation that needs to take place between local or national governments and residents."

In Bogotá, 70% of the population lives on 30% of the city's land area. And the city government has decided to maintain this situation, increasing density in certain neighborhoods to preserve surrounding natural spaces. By engaging in dialogue with residents and empowering them to participate in decision-making, a kind of social contract is being established.

We can also share examples where people live well in high-density areas, which can also be a source of social cohesion. Densification also means children playing together, women supporting each other, a sense of community, and access to transportation and shops nearby.

Question: Do you have any examples of successful building transformations?

Reply : "Rehabilitation is not simple, especially if you change the function of the building. There are many examples of offices converted into residential buildings in Boston, New York, and Sao Paulo. In Paris, too, there are excellent examples of recycling public buildings into social housing."

This isn't enough; more needs to be done, but it's important to have examples to show that it's technically and financially feasible. Renovation is becoming an increasingly important economic opportunity, but it's more expensive, and there are still gaps in terms of affordable prices for the general public. I think the challenge is to bridge this gap between sustainability and affordability.