Torrential downpours are a frequent occurrence in São Paulo — a quintessential feature of its tropical climate — but when the rains come, thoroughfares such as Avenida Nove de Julho often transform into churning rivers. The water reclaims ancient paths, buried beneath successive layers of concrete and asphalt.

The fate of Nove de Julho was typical of the many rivers and brooks in what become Latin America’s largest metropolis as development exploded in the 20th century. The river, like many others, was tunnelled to make way for cars above it.

This was brutal urbanisation in its purest form in the centre of the metropolis of some 20mn people. The new, industrial, outward-looking Brazil of the post-WWII period did very little to preserve its natural habitat, with little or no consideration for the environment.

In the suburbs, composed mostly of favelas (shanty towns), urban planning was absent when migrants from all over Brazil settled there, a lack of planning which has caused problems up to this day.

Concrete and contradictions

Understanding Sao Paulo’s climate vulnerability requires recognising that its developmental history was marked by a profound inequality, in one of the most unequal countries in the world.

The differences between centre and periphery lie at the heart of São Paulo's climate adaptation challenges.

The city grew up through what planners call "grey infrastructure" – intensive construction with minimal green areas resulting in a concrete jungle, river tunnelling and channelisation – but this approach varies dramatically between affluent central neighbourhoods and underserved peripheral communities.

This presents a challenge when adapting to climate change, according to Luciana Travassos, a professor in territorial planning at the Faculty of Social Sciences and Humanities at the Federal University ABC, one of Sao Paulo’s public universities.  

What developed countries forget when trying to establish common, global climate action plans is that in many parts of the world the urbanisation process they went through more than a century ago is still to happen, the professor said.

“Until very recently, the outskirts of Brazil’s large cities were not specifically considered in climate adaptation plans by public bodies, with the National Secretariat for the Peripheries only created in 2023. There are some very daunting tasks ahead, and planners should be focusing on two main areas: a very daunting challenge which, if overcome correctly, could give way to a very big opportunity,” Travassos told bnl.

“The challenge is related to urbanisation processes in the suburbs of large Brazilian cities, in terms of provision of infrastructure. In many favelas, built quickly and in a disorderly manner without much official planning involvement, infrastructure we take for granted in the cities is yet to be built. But this is where the opportunity to rethink our cities comes in.”

As in Sao Paolo’s concrete centre, streams and rivers are at the centre of the rethink in the favelas. While not channelled like in the centre, rivers in the favelas also only resemble rivers in the name: riverbanks are mostly occupied by precarious settlements for which the river acts a landfill of sorts – with the consequent harm to human and environmental health.

Climate crisis abound 

From a broader perspective, Brazil has had to grapple in the past two years with multiple climate crises across its vast geography, in what has been a true baptism of fire regarding climate change impact.

In 2024, the northern state of Amazonia – where water had always been abundant – had to put up with its second consecutive year of severe drought. The Amazon River recorded the lowest water levels since records began, disrupting livelihoods and businesses in an area where waterways are at the centre of the transport system. 

The drought led to widespread wildfires in many regions. In Sao Paulo, residents – poor and rich – had to endure significantly degraded air quality for weeks as the city was surrounded by several wildfires, hitting residents with respiratory-linked conditions especially hard.

Other parts of the country had the opposite problem. In May 2024, Brazil's southernmost state of Rio Grande do Sul experienced the country’s worst floods ever, taking more than 200 lives and paralysing the wealthy state for weeks.

Brasilia tackles the peripheries 

Until the current parliament was installed, urban planning, whether linked to the environment or not, was practically absent from federal policies. The National Secretariat for the Peripheries was only created in 2023 by executive order of President Luiz Inacio Lula da Silva, a first step in trying to address the issue.

After two years of deliberations, in May the secretariat launched a comprehensive guide focused on community-led climate adaptation strategies for favelas and peripheral areas, taking on previous projects piloted in some favelas.

The ‘Community Plans for Risk Reduction and Climate Adaptation’ guide was unveiled during a meeting of the BRICS Disaster Risk Reduction Group which took place in Brasilia, as Brazil holds this year BRICS’ rotating presidency.

If well-funded and well implemented – and those are two big ifs in Brazil – the guide could represent a turning point in the way the country addresses climate vulnerability in its most disadvantaged communities, according to experts.

The guide details Community Plans (PCRAs) as essential urban planning instruments for identifying and analysing risks from the perspective of residents who directly experience climate impacts, according to the secretariat’s head, Guilherme Simões.

Since 2024, twelve PCRAs have been implemented across Brazil in partnership with universities, municipalities, states and social movements, in an initiative conducted in cooperation with the Oswaldo Cruz Foundation (Fiocruz) through 2028.

The investments in the twelve plans stand at around BRL2mn ($350,000mn) – a drop in the ocean, but still a drop for urban planning in the favelas at last. The guide will be distributed to communities, managers and partner organisations involved in disaster risk reduction work, and will also be available on the Ministry of Cities website.

The absence of the authorities in many of Brazil’s favelas has often been offset by initiatives led by residents, who have long been self-managing in the face of the government's neglect of their daily problems, including those related to the climate. 

In fact, the National Secretariat for the Peripheries looked at some of those initiatives to compile the recently published guide as community governance networks based on the problems identified by residents have proved successful in addressing problems in climate-sensitive territories, such as hills, riverbanks and floodplains.

Recife leads the way 

Recife, the capital of the northern state of Pernambuco and Brazil’s ninth largest city, has been at the forefront of this. Recife ranks, together with Rio de Janeiro, as one of Brazil’s two most exposed cities to rising sea levels.

Launched in 2024 by a coalition of organisations with established histories in vulnerable territories across Recife's metropolitan region, the Governance to Confront Environmental Racism (Gera) Network is one of the best known initiatives. Gera Network has implemented adaptation strategies in riverside areas with particular emphasis on supporting civil society political advocacy.

Also in Recife, Communities for Climate has been a significant initiative organising campaigns focusing on metropolitan political advocacy through grassroots pressure on elected officials, organising demonstrations demanding climate mitigation and adaptation measures that respond to the specific needs of peripheral populations.

Planning tools 

Academic institutions are also contributing to community-based climate governance. The TIG-Periferia extension project led by Federal University of Pernambuco (UFPE) professors has had some success in strengthening monitoring and participatory mapping capabilities aimed at climate self-management processes. Since its inception, TIG has conducted climate literacy workshops in high-risk communities and collaborated with residents on mapping exercises to support community climate action plans. 

In collaboration with Observatório da Metrópoles Núcleo Recife, TIG has been updating and making publicly available the Geographic Information System for Precarious Settlements (SIGAP) in Recife's Metropolitan Region, a planning tool for precarious settlements and Special Zones of Social Interest.

Recife’s Town Hall has shown moral – and sometimes financial – support to some of these initiatives. The city’s mayor, Joao Campos, got the most votes of any candidate in the local elections in 2024, with a whopping 78% of votes cast.

At the state level, other citizen-led initiatives include the Northeast for Climate Resilience project, developed by NGO World Vision, working to reduce disaster risks in economically disadvantaged communities by strengthening connections between public authorities and community members, bridging traditional governance gaps.

The Waterproof Data project, associated with CEMADEN Education, represents another innovative approach, expanding flood data collection by recording rainfall using PET bottle rain gauges installed in schools and communities in risk areas, a citizen science approach which generates data used to develop more accurate flood forecasting models.

Planning without implementation

Brazil's approach to climate adaptation suffers from what Travassos identified as three fundamental problems, despite abundant planning expertise at multiple governmental levels.

"We have at the three government levels [city, state and federal], competent people who are thinking about planning alternatives, who are proposing planning alternatives within the scope of plans, programmes, and projects. So, we do have a significant critical mass of people thinking about adaptation to climate change," she explained.

“But this planning prowess faces critical limitations. Firstly, there is a lack of articulation with the other existing planning instruments, and climate adaptation plans are very poorly integrated. They may be finally being integrated into the discourse, but they are not generating different actions from the point of view of implementation.”

The second challenge relates to funding, she added. Just as those plans envisaged in offices of government departments are not integrated with other policies, they also suffer from low funding.

The third issue concerns the transferability of global climate solutions to Brazil's unique context in which the global climate change adaptation agenda is an agenda that is often very difficult to implement in Brazilian cities.

This disconnect creates a troubling dynamic where adaptations primarily benefit areas already enjoying greater privilege. In other words, what comes as a priority agenda in the global discussion may only be implemented in some parts of already urbanised cities.

Far from fixing the most pressing problems, this could potentially generate an even greater difference in treatment between central and peripheral areas.

The politics of climate action

The implementation of climate adaptation measures in Brazil is heavily influenced by political leadership at various governmental levels.

While recent federal initiatives show progress, Travassos was sceptical about their potential impact.

The stark contrast between administrations becomes particularly evident in climate policy.

"Obviously, the contrast between a government with a broad, left-leaning front like the one currently led by Lula is in stark contrast with the previous government led by [Jair] Bolsonaro, which was openly in denial about climate change. In this context, the difference is huge,” said Travassos.

“But the right and the centre-right still lead many state and local governments, and for them the importance of climate adaptation is not as important. Those of us who are concerned about this issues are holding their breath for next year’s general election.”

Current opinion polls suggest the current governing coalition, led by Lula’s Workers’ Party (PT), may struggle to reach a majority to form another government.

Changing perspectives

São Paulo's current urban form reflects specific historical visions of progress and development, and Travassos' family history provides a window into these generational perspectives on urban transformation.

"My grandfather was a public works engineer – he built the avenues Vinte e Três de Maio and Anhangabaú, which included some tunnelling of water streams. From my grandfather’s point of view, that was progress,” she said.

“But then, as I chose this field of work, my dad would say that I wanted to destroy everything my grandfather had done," Travassos recalled with a laugh.

As São Paulo and other large Brazilian cities confront increasingly severe climate impacts, the question of how to adapt these massive concrete urban conglomerations becomes increasingly urgent.

Policymakers face the challenge of rethinking the relationship between planning, implementation and equity during the remainder of this century.

As heavy rains continue to test São Paulo's urban infrastructure, reclaiming ancient waterways beneath concrete arteries, the city faces increasingly urgent choices about its future development.

The water flowing through its streets carries not just the remnants of tropical storms but also a profound message about urban planning priorities in an age of climate instability.

For Travassos and others working at the intersection of urban planning and climate adaptation, the challenge extends beyond technical solutions to include questions of justice, equity, and governance: creating a city that can weather coming storms while addressing the needs of all its residents, not just those in privileged central districts.

This article is part of a series on the impact of the Climate Crisis on major cities around the world. 

The other articles in the series are: 

Cities confront the rising tide of climate change

Taipei’s climate countdown

Jakarta’s sinking villages

Rising seas threaten India’s coastal cities