Aerial view of the cities of Novo Hamburgo and São LeopoldoAerial view of the cities of Novo Hamburgo and São Leopoldo

 

The destruction caused by the extreme rains recorded in Rio Grande do Sul between the end of April and the beginning of May is yet another tragic chapter in the effects of global climate change. Around 2.3 million people in 95% of Rio Grande do Sul's municipalities were affected, according to a Civil Defense report. Almost 600,000 people had to leave their homes and 171 deaths were confirmed by June 1st. The constant nature of climate disasters in Brazil poses new challenges to urban planning, which involve, among others, the issues of regulation and housing.


Unfortunately, this is a recurring scenario. It was the fourth extreme event in less than a year. In 2022, 233 people died in landslides caused by rain in Petrópolis, in the mountainous region of Rio de Janeiro. The following year, 65 died on the coast of São Paulo in a similar event. In 2023, there were 1,161 landslides, floods and drought events in the country, according to the National Center for Natural Disaster Monitoring and Alerts (Cemaden). It was also the year in which the Amazon rivers dried up at historic levels, with temperatures that reached 40°C (104°F).


For social scientist and architect José Police Neto, coordinator of the Housing & Real Estate Center at Laboratório Arq.Futuro, a decision which has to be made is whether cities will accept the risk of occupying the areas subject to flooding. “One of the reflections we started to make internally is how the much-needed changes in urban regulation end up guiding the city towards a new logic that was not the one that guided us until now”, he says.


The Federal Constitution (1988) and the City Statute (2001) assigned urban regulation and the organization of cities to municipalities. In 2015, the Statute of the Metropolis attempted to compose the task for the metropolitan public entities. “But the issue of contextualization and metropolitan governance is very far from being a reality in Brazil, and even the international experiences that have advanced a little in this direction are a complex process”, observes Police.


Until now, regulation has been guided by utilization coefficients, building setbacks, soil permeability and densification. Police comments that the hydrological and geotechnical bases were not treated with much emphasis. Brazilian cities grew where they always were, regardless of the security of the territory, as a rule established in areas that belonged to families who owned the land. “It was only around the 1960s that a slightly more public debate began in Brazil, with the participation of society, and architects and urban planners presented their international experiences”, observes the Laboratory specialist.

 

Scientific evidence


Faced with new climate threats, the solution, more than ever, is to resort to scientific parameters. In Police's opinion, it is the elements of science that will offer layers that, when superimposed, will tell where the city can accommodate itself with solidity and lower risk. “And we have to do a lot of math to see if the city stays on its feet like this”, he emphasizes.


Lawyer Safira De La Sala, deputy coordinator of the City and Regulation Center at Arq.Futuro Laboratory, reiterated the need for urban planning supported by scientific evidence. “Our main gap is recognizing that the city is not designed on a blank sheet of paper, but rather built on a region with its own ecosystem and environmental dynamics — and this cannot be ignored”, says Safira. “The role of the urban planner is to be guided by material and physical reality in all other themes that planning has already incorporated over the years, such as transport-oriented development, for example. It means understanding how all the themes that are familiar to planning relate and can be better applied based on territorial and risk analysis.”


Safira explains that, in 2012, the requirement for geotechnical maps used in urban planning — analysis of the geological, hydrological and geotechnical characteristics of a city — was added to the City Statute. These requirements, however, rarely direct planning in the country. “If there are areas of greater susceptibility to environmental risk — occupied mainly by vulnerable populations — the Master Plan and the Zoning Law, sometimes even the Construction Code, must disallow the occupation of these areas or require measures that, in case of occupation, reduce the vulnerability of people and the infrastructure involved”, highlights Safira.


As Undersecretary of Urban Development of the State of São Paulo, Police participated in negotiations on the reconstruction of São Sebastião, a city on the North Coast of São Paulo devastated by the rains of February 2023. The reconstruction of the region involved the relocation of around 750 families to safe locations. “In Rio Grande do Sul, we are talking about something like 15,000 to 18,000 families who will have their lives transformed because their neighborhoods can no longer exist”, he highlights. The need to “do a lot of math” to resettle people and preserve as many families as possible in their neighborhoods applies here. And, above all, to understand that the cost will be for everyone, not just for those who leave.


The great regulatory challenge will present itself in the form of creating new cities resilient to climate disasters. “The world will have to have this debate
because of climate change”, emphasizes Police. “These disasters often happen in mountainous regions, largely because they occupy the slopes, however there are risks in coastal cities as well. As the tides rise, the canals serve as a retention basin for rainwater. If the tide rises and the rains are more intense at the same time, the waters flood the coast for a week or two. There have already been episodes like this on the Brazilian coast. They have not yet produced a drowning city, but they signal that this risk is growing and that the social cost is enormous.”
 

The resilience equation


Another challenge will be to seek solutions from the experiences of other nations. Police recalls that the Netherlands and China spent a lot of money to develop and implement flood protection projects. In New Orleans, in the United States, rebuilding the system of dikes, pumps and floodgates cost 14.5 billion dollars, around 74 billion reais — in August 2005, Hurricane Katrina had devastated the city, breaking dikes and displacing 1 million people. “This challenge will require dedication, because we do not have enough wealth to transform cities into disaster-resistant places,” he believes.


Police continues: “As, on a large scale, it is the lower-income population that is exposed to the most susceptible areas, the tendency is for there to only be a public solution. As it is a public solution, it will depend on everyone's funding. So, it is a complex mixture of work and negotiation. This is not a donation due to the catastrophe, but rather a change in the logic of assembling cities, which will be born from scientific studies. The City Statute tries to give recommendations on what cannot happen. We will have to reformulate these recommendations, pointing to urban designs based on regulation. Gradually, an urban transformation is taking place to protect cities from climate change.”


The risks of flooding in the metropolitan region of Porto Alegre were known in advance, see the historic flood of 1941 — at the time, Lake Guaíba, which borders the capital of Rio Grande do Sul, rose 1.76 meters above the flood level, a mark now surpassed in 2024, when the water level rose 2.35 meters. “The issue is that we don’t have a culture focused on prevention”, comments Police. “Every time urban regulation is discussed, it is much more from the aspect of profit. Is it a ‘sin’ to try to value the city in regulatory processes? Of course not. The process of transforming the city cannot take away the value of the city. When debating a master plan or zoning law, you want your asset to increase in value and for the city to increase in value. The issue is that every time the city increases in value, access to it by the lower-income population becomes even more difficult. The city can become more expensive, and the general population does not become much richer at the same time.”


Data and evidence will be indispensable for the urban planning debate. In short, it is known that, by reducing the size of occupied areas, access to land will be reduced and the city's general sales value (PSV) will fall. The square meter tends to increase in value, because it will become scarce. The typical solution is to densify the city, through taller and more robust buildings, to accommodate a larger population in safer areas. Smaller housing units may be needed because there will be fewer square meters available.


Adapting to climate change is not a ready-made recipe. Planning depends on the geographic characteristics and infrastructure already established in each location. “It is a time-consuming process, which affects everyone, from the elites to the lower-income population”, emphasizes Police. “It is a process that awakens passions, because there are those who are passionate about the vertical city and others who are very passionate about the horizontal city. However, it is a process that we will have to live through and that will need to be agreed upon with society.”

 

The three fundamentals


In adapting to increasingly frequent extreme climate events, the challenge of urban planning is to be able to incorporate the different gradations of risk of loss of human life, property and wealth and identify responses to face these risks. Safira cites three fundamental steps to guarantee the protection of the population: prevention, risk management and reconstruction.


The path begins with regulating land use and occupation and choosing the most appropriate construction techniques for local conditions. Geotechnical maps, for example, estimate return times for climate events and provide data that helps organize and minimize the impact on citizens' lives. This information can be used to regulate source drainage control devices that slow water runoff or increase soil infiltration. Or even nature-based solutions, a concept that encompasses engineering ideas that try to reproduce natural processes.


According to Safira, the issue is complicated in the so-called “informal city”, which is outside of legality and has few resources to adapt to catastrophes. Therefore, the second step is risk management. She says that the creation of the Cemaden Monitoring and Warning Center, in 2012, was an important milestone in Brazilian disaster reduction policy. “However, there is no point in just having the best monitoring and alert center if there is no contingency protocol for practical action, carried out by technicians from different areas”, she states. “The monitoring and alert system must be connected to a plan that allows the population, civil defense and governments to know how to act at the time of alert. Today, this is the main gap in the risk management system in Brazil.”


Finally, the third stage is the reconstruction system of the affected city, which also involves a macroeconomic structure for collecting and managing financing funds. Territorial planning can be a strategic issue. “If we start to direct urban development, vacating risk areas where lower-income populations live, we can open up other financing possibilities”, says Safira. The report “Natural catastrophes in 2023”, by Swiss reinsurer Swiss Re, indicates that losses covered by natural catastrophe insurance have outpaced global economic growth over the last 30 years. The supply and cost of this insurance — directly linked to the risk of the accident — could decrease due to the implementation of adaptation measures to natural disasters and the construction of resilient infrastructures, the report states.


In rebuilding the city, removing and relocating families is a delicate decision. Environmental engineer Juliana Mitkiewicz, coordinator of the Laboratory's Women and Territories Center, emphasizes that climate justice becomes a central concept at this critical moment, when it is observed that it is the most vulnerable populations that suffer the greatest losses in natural disasters. “These communities, often already marginalized, face the loss of their homes, their livelihoods and, in some cases, lives,” she notes. “It is an issue that goes beyond a simple emergency response. It’s a question of equity and human rights.”


Removal and relocation mean more than just moving people from one place to another. “We are talking about uprooting lives, breaking community ties and displacing cultures”, highlights Juliana. “Many of these families will be relocated to unfamiliar areas, far from their support networks and their historical links. This can have a profound impact not only on physical well-being but also on psychological and social aspects. Therefore, any urban and regulatory planning that intends to be effective and fair must consider these points.”


Juliana adds: “Decisions cannot be made from the top down, without the active participation and consent of the affected communities. We must ensure that the voices of these populations are heard and that their specific needs are met. This implies in-depth debates about the territory and infrastructure of cities, considering both urban sprawl and verticalization, based on studies, solid data and evidence, and social participation. Only with an inclusive approach based on climate justice will we be able to create resilient cities that protect all their inhabitants, especially the most vulnerable, from the inevitable changes that the climate imposes on us.”

 



English version:  Ana Clara Kransfeld

English version review: Randy Charles Epping




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