Climate-related risks: implications for municipal governments in Brazil

1. INTRODUCTION

The intensification of extreme events amplifies the risk of urban disasters, which is a critical issue in today’s climate emergency debate. In 2020 alone, socio-environmental disaster events affected 98.4 million people and were responsible for economic losses of at least US$171.3 billion (CRED & UNDRR 2021). Governments have responded to such climate-related risks by launching policies and programmes in different areas and levels (Vieira et al. 2024). In general, national governments assume attributions related to policy planning and financing of subnational governments, which, in turn, become responsible for planning and executing such policies in response to their specific territorial and socio-environmental features.

In spite of such relevance, local governments often have heterogeneous capacity to properly plan and execute such actions (Cid et al. 2024; Cvetković et al. 2021; McGregor et al. 2022; Londe et al. 2015). The consequences of the mismatch between assigned responsibilities and available capacities are not merely administrative. They have material implications for vulnerability reduction in the built environment (Di Giulio et al. 2025). Cities with consolidated institutions, technical teams and the required financial resources might translate federal goals into territorial planning, upgrading infrastructure and restricting occupation of risk-prone areas. Meanwhile, municipalities with limited capacity struggle to implement even basic requirements, potentially reinforcing vulnerabilities precisely where climate exposure is highest. Even though this is not a direct relationship between capacity and climate-related risks responses, since municipalities with higher levels of capacity might as well face higher levels of informality and precariousness, this dynamic can amplify existing asymmetries between cities and regions marked by significant social and urban inequalities.

Recent studies have advanced this debate by arguing that municipal capacity for responding to climate-related risks relies on other factors, besides federal policies. These studies point to subnational institutional arrangements (Barbi & Rei 2023), multilevel governance dynamics (Ishtiaque et al. 2021), and collaboration and learning processes (Eakin 2026; Fisher & Dodman 2019). However, few studies analyse how federal regulation interact with municipal contexts.

The present article contributes to this debate by examining how Brazilian federal legal frameworks assign responsibilities to municipalities in sectors directly connected to climate adaptation and disaster risk management, and what this implies for local implementation under heterogeneous institutional and territorial conditions. It investigates how the concentration of regulatory, operational and coordinative mandates at the municipal level interacts with local contextual features—such as municipal capacity, accumulated experience with disasters and territorial risk profile—to shape the conditions under which implementation is, or is not, feasible.

Empirically, the article develops a multilevel approach. On the one hand, it analyses the case of Brazil, where climate-related disasters have become more frequent and more intense in the last decades, with almost all its municipalities being affected by disasters between 2013 and 2023 (CMN 2025), and there a significant heterogeneity among municipal governments in terms of capacity for planning and responding to climate-related risks (Londe et al. 2015). The marked heterogeneity in the technical and fiscal capacities of Brazilian local governments has shaped, and often constrained, the effectiveness of locally implemented policies (Marchezini et al. 2025; Londe et al. 2015).

The country is an interesting case study for reflecting on broader Global South urban dynamics, where climate risks increasingly intersect with historical patterns of exclusion and uneven development. While approximately 1.81 billion people (23% of the world’s population) are directly exposed to flood risks, 89% of this population lives in low- and middle-income countries (Rentschler et al. 2022).

On the other hand, the article investigates local level developments by studying the Greater ABC (GABC) Region, in the São Paulo Metropolitan area. Comprising seven municipalities with a shared industrial legacy, the region combines high population density with significant environmental remnants, creating complex territorial configurations for risk management (Nogueira & Canil 2017).

Through an exploratory review of federal legislation combined with an examination of experiences in the GABC and semi-structured interviews, the study reveals how well-intentioned legal frameworks impacted differently on local governments, depending on their previous experience with disasters, capacities and territorial conditions. These impact can inadvertently create municipal legal overload and fail to reduce the inequalities and vulnerabilities they were designed to address.

The paper is structured as follows. Section 2 examines the role and limits of municipalities in climate-related risk governance. Section 3 presents the methodological procedures. Section 4 analyses the federal legal framework, mapping municipal responsibilities across four policy axes connected to the built environment. Section 5 examines how this framework operates in the municipalities of the GABC. Section 6 discusses the implications of these findings. Section 7 concludes.

2. CLIMATE-RELATED RISKS AND MUNICIPALITIES

Extreme events are increasingly recognised as drivers of socio-environmental disasters, placing climate risk at the centre of urban policy debate. Even though this sort of disaster has a direct connection with the outbreak of a hazard, such as a flood and/or a landslide, there is nothing ‘natural’ about disasters as they only take place when natural hazards meet conditions of vulnerability in the built environment, which is informed by socio-economic conditions (O’Keefe et al. 1976). Even if climate change is expected to make extreme weather events more frequent and more severe, it is necessary to acknowledge the human-made components of both vulnerability and hazard. Therefore, human agency has a significant role in proactively responding to disaster causes and effects.

The literature has advanced the understanding of climate-related risks by arguing that the risk is the product of a necessarily contextualised equation that conflates the exposure to the hazard, the vulnerability of households and citizens, governmental capacity to plan and act, and the existence of mitigation measures (Wisner et al. 2015; Crowley et al. 2022). Vulnerability and governmental capacity, notwithstanding, are not homogeneously spread among countries and cities. There are countries, territories and peoples with higher vulnerability and lesser capacity, resulting in a disproportional exposure to risks of disasters. This is the case of many cities in the Global South, characterised by urban poverty and rapid, informal and fragmented urban growth, resulting in unequal access to urban infrastructure and public services, high levels of environmental and socio-economic inequality, and vulnerability (Lobo et al. 2023; Dodman et al. 2019; Mitlin & Satterthwaite 2013).

Against this background, and in line with international frameworks, such as the Sendai Framework for Disaster Risk Reduction 2015–2030 (UNDRR 2015), national and subnational governments have begun to develop programmes and legal frameworks to structure governmental responses on climate adaptation and risk reduction (Vieira et al. 2024). National governments usually provide guidelines, nationwide policies, data and financial resources for subnational governments, which, in turn, assume the main role in the planning and implementation of climate-related risk responses at the local level. In this arrangement, municipal governments’ capacity for implementing policy is critical to achieving disaster-risk reduction and disaster-resilience outcomes (Di Giulio et al. 2025; Lyles et al. 2014; Torabi et al. 2017).

Notwithstanding, local governments often have a heterogeneous capacity to plan and execute such actions properly (Cid et al. 2024; Cvetković et al. 2021; McGregor et al. 2022; Londe et al. 2015). Governmental apparatuses with a low organisational capacity to process the complexity of climate policies may distort and even ruin them (Chudnovsky & Fernandez 2024). As a result, there is a latent risk that current intergovernmental climate-related risk policies fail to reduce existing asymmetries between cities and regions.

Furthermore, the literature on capacities for disasters and their risk management is still emergent. It lacks conceptual and operational definitions of some of its founding concepts, e.g. on what constitutes and how to measure such capacity (Oda et al. 2025; Scott & Few 2016). The concepts of state, institutional and organisational capacity, for example, are not clearly defined, even though they are generally associated with the availability of human and financial resources, administrative skills, technical training, and data management. They are described as essential for achieving concrete and tangible outcomes (Oda et al. 2025).

Recent studies have advanced this debate in two directions. By bridging this debate with the areas of political science and public policy, studies have argued that policy capacity is essential for disaster management (Capano & Toth 2023, 2024; Christensen et al. 2016; Oda et al. 2025). This is defined as the set of skills and resources necessary to perform policy formulation and implementation functions (Capano & Toth 2024; Wu et al. 2015). These skills and competencies may be analytical, operational or political, and manifest at the individual, organisational and systemic levels (Wu et al. 2015). The existence of such capacity, however, does not guarantee that it will be used for policymaking, since it can be activated (or not) by the decisions of political leaders and by the implementation arrangements (Pires & Gomide 2024; Centeno et al. 2017). It is precisely the interaction between policy capacity, political leadership and social support that seems to be fundamental to the success of public policies (Centeno et al. 2017)—a combination that remains difficult to achieve in contexts marked by high levels of precariousness and cumulative spatial inequalities (Bittencourt et al. 2021).

However, the literature on climate change and disaster-risk management has argued that municipal potentiality for having solid subnational responses to climate-related risks relies on other factors, besides federal policies and the formal existence of indicators of municipal capacity. These studies contend that the robustness of policies for climate-related risks by subnational governments relies on the existence of previous institutional arrangements related to climate change, including the participation of several stakeholders (Barbi & Rei 2023); of collaboration and learning processes involving multiple stakeholders (Eakin 2026; Fisher & Dodman 2019); and aspects related to the multilevel governance, such as how the structure of relations and their associated power dynamics between these actors affect adaptation governance process at different levels (Ishtiaque et al. 2021).

Building on these debates, this article contributes to the debate by examining how Brazilian federal legal frameworks assign responsibilities to municipalities in sectors directly connected to climate adaptation and disaster-risk management, and what this implies for local implementation under heterogeneous institutional and territorial conditions. It is assumed that municipal responses to federal climate risk regulations are shaped by the interaction between national policy mandates and local contextual conditions, such as municipal capacity, disaster experience and territorial risk profile. Municipal action in climate-risk governance, therefore, is not self-executing: where broad responsibilities are not matched by stable support, coordination mechanisms and enabling conditions, the promotion of federal mandates without the adequate induction of local capacities is unlikely to produce structural changes in the unequal distribution of vulnerability across municipalities.

3. METHOD AND DATA

This study is an exploratory qualitative analysis of how Brazilian federal mandates relate to local disaster risk management and climate adaptation in the built environment. The GABC Region provides the empirical setting for examining how federal mandates interact with local governance conditions. The region is also analytically useful because it combines a regional coordination mechanism, hydrographic and environmental interdependencies that cross municipal boundaries, and persistent precarious settlements in risk-prone areas.

To investigate how municipalities with varied capacities and experiences respond to federal normatives on climate-related risks, the research combines two complementary procedures: a documentary review of the federal legal frameworks and semi-structured interviews with municipal officials in the GABC. For full methodological details, including the interview guide and a list of reviewed legal instruments, see the supplemental data online.

4. FEDERAL LEGAL SYSTEM AND MUNICIPAL RESPONSIBILITIES IN THE BUILT ENVIRONMENT

Brazil’s 1988 Constitution assigns municipalities a central and unavoidable role: they are autonomous entities of the federation responsible for executing urban development policy within their territory. Since the early 2000s, this constitutional mandate has been progressively detailed through sectoral legislation directly connected to the built environment. Table 2 reorganises these legal assignments into four policy axes: territorial planning, land use and housing; urban infrastructure and service provision; environmental regulation; and disaster risk and civil defence, synthesising the municipal role produced by each framework and its relevance for climate adaptation.

The first policy axis concerns territorial planning, land use and housing. The federal legal framework positions municipalities as territorial regulators and land managers, a role operationalised mainly through the City Statute (Law 10.257/2001), which defines the master plan as the basic instrument of municipal urban policy. Through this instrument, municipalities regulate land use and occupation, guide urban expansion, and organise the territorial distribution of infrastructure and public facilities.

This planning framework was later connected more directly to disaster risk. Amendments introduced by the National Policy for Protection and Civil Defence required municipalities susceptible to disasters to incorporate into their master plans risk mapping, land-use parameters, preventive measures and drainage provisions for areas exposed to landslides and flash floods, including possible relocation. The urban land regularisation framework (Reurb, Law 13.465/2017) reinforced municipal centrality by assigning local governments a decisive role in regularisation procedures, including slum upgrading, approval of urbanistic projects and, where necessary, resettlement solutions in risk situations. The Metropolis Statute (Law 13.089/2015) adds a metropolitan layer by requiring municipal master plans to be compatible with the integrated urban development plan of the metropolitan unit. Together, these instruments place municipalities at the centre of land regulation, urban expansion and the incorporation of precarious settlements into the formal city—functions that are critical for adaptation because exposure to floods, landslides and related hazards is strongly shaped by patterns of land occupation and urban growth.

The second policy axis concerns urban infrastructure and service provision. Here, the legal framework positions municipalities as planners, providers, regulators or supervisors of key urban systems whose design, maintenance and coordination directly affect urban resilience to extreme rainfall, flooding and service disruption.

Federal legislation requires municipalities to prepare mobility plans aligned with their master plans (Law 12.587/2012), municipal sanitation plans compliant with federal regulatory standards (Laws 11.445/2007 and 14.026/2020), and municipal waste management plans organising selective collection and reverse-logistics schemes (Law 12.305/2010). Municipalities remain responsible for the territorial and institutional organisation of these systems even when direct provision is shared, delegated or contracted out. In practice, these systems are implemented in the same urban space and depend on shared streets, drainage networks and underground infrastructure. Their operation, therefore, requires continuous coordination across sectors that are legally distinct but territorially interdependent.

The third policy axis concerns environmental regulation. Federal legislation does not simply create environmental objectives external to urban policy. Instead, it recognises the built environment as part of the broader environment, whose quality must be preserved to ensure human wellbeing, promoting compatibility between ecological considerations and socio-economic development. Municipalities therefore act as local gatekeepers of environmentally sensitive land by adapting urban occupation to water protection rules and ecological restrictions defined in national law.

The National Water Resources Policy (Law 9.433/1997) defines the river basin as the territorial unit for water management and requires municipalities to integrate local policies on land use, sanitation, soil conservation and the environment with basin-level management objectives. The Forest Code (Law 12.651/2012) establishes rules for the protection of permanent preservation areas, such as riparian buffers, hilltops and steep slopes that directly constrain occupation in the zones most exposed to floods and landslides. The National Policy on Climate Change (Law 12.187/2009) adds a cross-cutting layer by establishing national objectives for mitigation and adaptation and requiring their integration into sectoral policies. For municipalities, this means climate adaptation is not a standalone field of action but must be incorporated into existing planning and regulatory frameworks connected to the built environment.

The final policy axis concerns disaster risk management and civil defence. The National Policy for Protection and Civil Defence (Law 12.608/2012) assigns municipalities the most operationally defined set of responsibilities in this analysis: identifying and mapping risk areas, monitoring critical zones, issuing alerts, preventing new occupations in hazardous areas, organising shelters and carrying out simulation exercises. The framework also links civil defence to territorial planning, requiring the incorporation of risk provisions into master plans. Implementation remains constrained by local resources and capacities, but the legal specification of municipal duties is comparatively clearer here than in other sectors.

Taken together, these four policy axes show that Brazilian federal legislation assigns municipalities a central role in shaping the built environment in ways that are directly relevant to climate adaptation. These responsibilities converge in the same municipal territory and must be translated into action by governments whose capacity, experience with disasters and territorial conditions vary substantially. The following section examines how this framework operates in the municipalities of the GABC.

5. THE GABC REGION: PERSISTENT VULNERABILITIES

The GABC comprises the municipalities of Santo André, São Bernardo do Campo, São Caetano do Sul, Diadema, Mauá, Ribeirão Pires and Rio Grande da Serra, and is located in the south-east of the São Paulo Metropolitan Region (SPMR), adjacent to São Paulo city, South America’s largest metropolis. It covers an area of approximately 830 km², home to 2.7 million people, with more than 80% living in urban areas (IBGE 2022).

The territory presents highly diverse characteristics. It is a predominantly urban region with strong representation from industrial and service sectors. At the same time, it encompasses significant environmental attributes, including remnants of native vegetation and protected areas that play an important role in safeguarding water resources for public supply. The region is characterised by undulating topography and an extensive hydrographic network. Among its watercourses is the Tamanduateí River, which became a central axis for the urban expansion of the SPMR. In contrast, other basins in the territory contain strategic water sources and are subject to specific state regulations restricting land use and occupation in order to protect water quantity and quality.

The physical–territorial and climatological characteristics favour susceptibility to flooding and gravitational mass movements. According to mapping by the Brazilian Geological Survey (SGB), the seven municipalities contain areas of high susceptibility associated with topography, geological conditions and precipitation patterns (SGB 2015). When occupation characteristics are considered, these configure disaster risk situations. Currently, the GABC territory combines, unevenly, areas of high population density, recent urban expansion spaces and significant environmental remnants. Figure 1 illustrates the territorial context of the region.

Figure 1

The relationship between urbanisation and hydrographic configuration is central to understanding the current picture. The built environment is characterised by large areas of soil impermeability and the prioritisation of individual wheel-based transportation, combined with conventional drainage solutions. In central areas, watercourses have been channelled to expel stormwater rapidly downstream in urban settings (Travassos & Momm-Schult 2013), thereby enabling the occupation of the original floodplain areas.

These structural vulnerabilities are being intensified by changing precipitation patterns. Recent studies on climatic indices in the region have identified more intense daily rainfall in recent years, which acts as a trigger for floods and landslides in the most susceptible areas (Valverde et al. 2018). This territorial configuration shapes the conditions under which municipalities exercise the responsibilities assigned by the federal legal framework. The following examines how local governments respond to these demands, considering their institutional capacity, experience with disasters and the specificities of risk in the territory.

Despite territorial vulnerabilities, the GABC presents institutional capacity for disaster risk management above the national average, albeit unevenly. The municipal capacity indicator (MCI),³ an index managed by the federal government, classifies Brazilian municipalities on a scale from A to D according to their institutional capacity in disaster prevention, mitigation, preparedness, and response and recovery. The indicator considers three dimensions: I, planning and management instruments; II, intersectoral coordination and capacities; III, policies, programmes and actions. Table 3 shows the classification of the GABC municipalities according to the MCI.

The data reveal considerable variation within the region. MCI classifications are determined not by total score alone, but by whether a municipality meets minimum thresholds across all three dimensions simultaneously; a failure to reach the required minimum in any single dimension results in reclassification to the next lower category regardless of overall performance. Since all seven GABC municipalities are listed among prioritised municipalities for flood and landslide susceptibility, they share the same risk profile reference group, making their scores directly comparable. Three municipalities, namely Santo André, Mauá and Ribeirão Pires, achieve category A, meeting or exceeding the minimum across all three dimensions. São Bernardo do Campo, Rio Grande da Serra and Diadema are classified as B, with sufficient performance in planning (I) and coordination (II). São Caetano do Sul is the only municipality classified as C: despite strong scores in the first two dimensions, it falls below the minimum required in the policies, programmes and actions dimension (III).

The interview data highlight the importance of these three dimensions for municipal capacity in disaster risk management. All respondents emphasised the relevance of risk mapping for prevention and response activities, the need for civil defence to work jointly with other municipal departments, and the role of institutional partnerships across different governance scales.

Santo André and São Bernardo do Campo emphasised the importance of organising risk management under a municipal governance system, stressing the need for sectoral coordination. As noted by one interviewee:

Similarly, in São Bernardo do Campo:

Interviewed managers also highlighted that the publication of the National Policy for Protection and Civil Defence (Law 12,608/2012) was a key milestone that supported and guided the establishment of municipal systems for disaster risk management.

Intersectoral coordination is also important due to the need for multiple municipal departments to act in response to the vulnerability conditions that shape disaster risk in the studied context. Interviewees highlighted the need for joint action with housing, urban planning, health and social assistance teams, noting that risk situations are often linked to precarious housing and social vulnerability. As one respondent explained:

Another interviewee noted:

Similarly:

In some cases, emergency response requires coordination with social services:

Taken together, these accounts highlight that regulatory responsibilities related to land regularisation, urban planning and land-use control need to operate in conjunction with the municipal protection and civil defence system as part of an integrated approach to disaster risk management.

Municipal action in the territory therefore deals with the multiple demands generated both in the phases preceding disasters and in the response following disaster events. In this context, municipal managers frequently expressed a perception of institutional overload at the local level. As one respondent stated:

Another noted:

Interviewees directly associated this issue with the budgetary implications of disaster risk management and the financial capacity required to structure teams, highlighting asymmetries between larger and smaller municipalities. As one respondent observed:

Another interviewee added:

while a coordinator from a smaller municipality explained:

References to support from other government levels were mainly related to budgetary capacity. States and the federal government appear as relevant actors in the provision of equipment and financial resources. For example:

The multilevel dimension presents a particular feature in the GABC Region, namely the presence of the GABC Intermunicipal Consortium, established in the 1990s as a formal mechanism for coordinated regional governance. Interviewees emphasised the role of the consortium in fostering regional coordination, particularly through the Risk Working Group, which functions as a platform for exchanging experiences and aligning practices among municipal civil defence teams. They also highlighted the importance of ad hoc cooperative initiatives to mobilise resources for specific actions, including joint procurement processes, such as the collective purchase of uniforms for civil defence teams. For municipalities with more limited institutional and budgetary capacity (particularly Rio Grande da Serra), the consortium emerged in the interviews as an especially relevant mechanism for supporting local action. The representative from Ribeirão Pires also highlighted the importance of the consortium in coordinating the development of key risk management instruments, such as risk-mapping (I5). Recently, the consortium intermediated the mobilisation of resources from the State Water Resources Fund to support the preparation of municipal risk reduction plans for Ribeirão Pires, Diadema and Rio Grande da Serra.

Effectively, the most disaster-susceptible areas should be considered priorities for housing policy, for example. Despite these advances and efforts to strengthen coordination both within municipalities and across the region, significant challenges remain for municipal action across the different dimensions of climate adaptation. In particular, areas most susceptible to disasters should be prioritised in sectoral policies such as housing policy. Brazilian legislation allows the consolidation of precarious settlements in areas adjoining watercourses, for example. However, despite the existence of specific regulation, its implementation faces obstacles given the complexity and magnitude of the problem. As Nogueira et al. (2014) observe, municipalities constitute the primary locus of policy implementation, yet they represent the weakest tier of Brazil’s federal system in both economic and technical–administrative capacity, creating a fundamental tension for effective policy delivery at the local level.

The institutional framework needs to respond to growing demands in a context of intensifying extreme events. Administrative capacity must be analysed alongside territorial specificities. In the case of GABC, although there are cooperation efforts and implementation of management instruments, challenges remain that are intrinsic to the territorial configuration itself. The region underwent an intense industrialisation process between the 1950s and the 1980s, marked by the installation of automotive assembly plants and meta-industries, especially in São Bernardo do Campo and Santo André. This process triggered accelerated, uneven urbanisation, attracting large contingents of workers from other regions of the country, mostly on low wages. Population growth exceeded formal housing supply capacity, resulting in the expansion of precarious settlements as an alternative for the low-income population, frequently located in risk areas or environmentally sensitive areas, such as hillsides and riverbanks, despite the existence of regulation for land use and occupation (Maricato 2003).

In 2022, the region recorded 222,683 households in precarious settlements, occupying 2832.43 ha. The figures represent increases of 4.5% in households and 6.9% in area compared with 2017 (Feitosa 2022). Despite consolidated urbanisation, the data indicate the continuity of occupation of sensitive areas by precarious housing. The study also notes that around one-third of these settlements present medium or high susceptibility to floods and landslides.

From 2000 to 2024, 37 deaths and 23,451 people directly affected by disasters of hydrogeological, meteorological and other origins were recorded across the seven GABC municipalities, according to data from the Digital Atlas of Disasters in Brazil, a platform that gathers records of disasters occurring in the country managed by the Ministry of Integration and Regional Development (MIDR) (2026). The consequences of disasters in this period totalled more than US$52 million in material damage, according to the same source.

The substantial quantity of precarious settlements in the region, in itself, indicates the challenging scenario. Even though the municipalities are endowed with technical–administrative capacity, action on all settlements is unfeasible, given the dimension and complexity of the problem. Ramalho (2013) analyses approval processes for land regularisation in four settlements in the Alvarenga Basin, São Bernardo do Campo, and verifies that six years of processing in the environmental authority were necessary before approval. The approved processes addressed actions affecting less than 3% of the settlements mapped by the local housing plan within the water-source-protection area. Since then, other specific initiatives have moved forward, but criticism of the slowness of the approval processes has not been overcome.

The concentration of legal responsibilities at the municipal level is reinforced by external accountability mechanisms that create additional pressure for implementation, operating alongside local institutional capacity. Public prosecutors use civil inquiries to require municipalities to publish risk maps, contingency plans and early-warning systems, with non-compliance triggering escalating civil actions, including injunctions, fines and asset-freezing. Civil courts adjudicate liability for preventable flood and landslide losses, awarding damages and mandating remedial works. Audit courts scrutinise spending on drainage, slope stabilisation and emergency procurement, issuing fines and referring suspected fraud to prosecutors. Integrity breaches in disaster procurement can lead to administrative improbity or criminal cases, resulting in loss of office, suspended political rights and restitution requirements. These instruments collectively ensure consequences for governmental omission.

The GABC illustrates these mechanisms in action: the court of auditors warned mayors to take preventive measures ahead of the 2024 rainy season, while the public prosecutor’s office continues investigating a flood-alert application, costing around US$375,000, that malfunctioned during flooding. In Mauá, ongoing prosecutorial demands for preventive measures reflect institutional responses to recurring tragedies, including five rain-related deaths in recent years. However, even if legal mechanisms for accountability are triggered, the effectiveness of any judicial decisions still depends on the administrative capacity of the municipality. This capacity, as demonstrated, proves to be limited in the face of the complexity of urban and environmental demands in the region.

This scenario reveals the permanent tension between urban growth, socio-environmental vulnerabilities and limitations in municipal state capacity. In the GABC, three municipalities display stronger institutional capacity, while the others, although presenting more limitations, still perform above the national average. Cooperative action through the intermunicipal consortium also plays a relevant role, contributing to regional-scale governance and action. However, the significant persistence of precarious settlements in vulnerable areas means that risk management policies remain highly dependent on intersectoral coordination and on the capacity to address housing-related challenges.

6. DISCUSSION

The GABC Region case helps clarify the implications of the federal legal framework identified in Section 4. The issue is not simply that municipalities bear extensive responsibilities in climate adaptation and disaster risk management. Rather, municipalities become the point where regulatory, operational and coordinative functions converge across sectors that are territorially interdependent. In the built environment, land-use control, precarious-settlement upgrading, environmental restrictions, infrastructure provision and civil defence routines are not implemented separately in practice. They meet in the same urban space and must be translated into routine decisions by local governments with varying capacity, experience with disasters and territorial conditions. The GABC case shows how this institutional design places municipalities at the centre of adaptation-related action, but also concentrates on them the burden of making fragmented sectoral mandates work under complex metropolitan conditions. This condition is hereby called municipal legal overload: the mismatch between the breadth of legally assigned responsibilities and the enabling conditions available for their implementation.

At the same time, the case suggests that persistent vulnerabilities cannot be explained by a single factor such as lack of capacity alone. The GABC municipalities present institutional capacity above the national average, yet the region still contains extensive precarious settlements in environmentally sensitive and risk-prone areas, and long-standing difficulties in advancing land regularisation and integrated risk reduction. The Alvarenga Basin case in São Bernardo do Campo illustrates this well: six years of environmental licensing were required to address actions covering less than 3% of the settlements mapped in the water-source-protection area, despite the municipality holding one of the stronger institutional profiles in the region. Legal overload therefore operates together with territorial complexity and fragmented sectoral coordination, and is further shaped by the previous experience of municipalities with disasters.

The case also helps qualify the role of regional and institutional mediating arrangements. Cooperative action through the intermunicipal consortium contributes to governance at the regional scale, especially where risks and infrastructure systems transcend municipal boundaries. For municipalities with more limited institutional and budgetary capacity, such as Rio Grande da Serra, whose civil defence coordinator noted that revenue constraints directly limit the structuring of local teams, the consortium has functioned as a compensatory mechanism, enabling joint procurement and the exchange of practices that would otherwise be unfeasible at the individual municipal level. Accountability mechanisms also create pressure for implementation, as illustrated by the court of auditors’ warning issued to GABC mayors ahead of the 2024 rainy season and the ongoing investigation into the malfunctioning flood-alert application. However, neither regional coordination nor external oversight displaces the core fact that legal and operational responsibility remains concentrated in municipalities. The main implication is that municipal centrality requires more stable enabling conditions if adaptation is to be implemented equitably. This includes stronger vertical support, more routine intersectoral coordination, and institutional arrangements capable of addressing metropolitan and basin-scale problems without leaving implementation gaps to be absorbed locally, and absorbed most heavily by those municipalities with the least capacity to do so.

7. CONCLUSIONS

This paper examined how Brazilian federal legal frameworks assign responsibilities to municipalities in sectors directly connected to climate adaptation and disaster risk management, and what this implies for local implementation under heterogeneous institutional and territorial conditions. Municipalities are positioned simultaneously as territorial regulators, infrastructure providers, environmental gatekeepers and civil defence operators. These mandates converge in the same municipal territory but are implemented by governments whose capacity, experience with disasters and territorial conditions vary substantially. Where this variation is not accounted for, legal assignment is unlikely to produce structural changes in the unequal distribution of vulnerability across municipalities.

The Greater ABC (GABC) Region of Brazil case illustrates this tension. Even with institutional capacity above the national average, the persistence of precarious settlements in risk-prone areas reveals the limits of legal centrality without enabling conditions. The mismatch between assigned responsibilities and available support is most acute in municipalities with more limited institutional capacity, and is compounded by territorial complexity, fragmented intersectoral coordination and limited accumulated experience with disasters.

This study is bounded by its focus on one metropolitan sub-region and on civil defence coordinators as the primary source of institutional perspectives. Future research could extend to other Brazilian metropolitan regions, examine how different intergovernmental support arrangements condition the translation of federal mandates into local action, and investigate more systematically how accumulated disaster experience shapes institutional learning across municipalities with varying capacity levels.

DATA ACCESSIBILITY

The data supporting the findings were collected by the authors from official government web portals and are publicly available. Interview data are not publicly available due to the privacy of the research participants. Further information is provided in the supplemental data online.

ETHICAL APPROVAL

All interviewees were informed about the objectives and scope of the research prior to the interviews, and consent to participate was obtained. Participants were also explicitly told that they could decline to answer any questions they were uncomfortable addressing. To ensure ethical research practices, the identities of interviewees were anonymised in the presentation of the results, following ethical approval (CAAE: 96193626.9.0000.5594).

SUPPLEMENTAL DATA

The supplemental data file for this article can be accessed at: https://doi.org/10.5334/bc.717.s1

• Table S1: Federal laws reviewed in the legal analysis

• Table S2: Categories and criteria used to analyse federal legislation

• Table S3: Municipal mandates related to the built environment under Brazil’s federal legal framework

• Table S4: List of interviews and informants

• Table S5: Semi-structured interview guide