A Spatial Evolution Framework for Urban Informality under Climate Stress

Thesis Abstract

Urban informal settlements persist as a salient facet of city dynamics in the face of climate variability, yet their spatial evolution under simultaneous governance and environmental stress remains inadequately understood. This study addresses the problem that current urban informality models inadequately capture how climate-induced shocks—heat, flooding, and precipitation variability—interact with built-environment constraints to drive informal spatial expansion, relocation, and densification. The aim is to develop a Spatial Evolution Framework for Urban Informality under Climate Stress that explicates the mechanisms, drivers, and feedbacks linking climate stressors to informal land-use change, while integrating governance, access to services, and social vulnerability. The specific objectives are to (i) map temporal changes in informal settlements in relation to climate exposure over a ten-year period; (ii) identify spatial pathways of informal expansion, consolidation, and relocation under flood and heat risk; (iii) quantify the influence of environmental stressors, tenure insecurity, and service delivery on informal settlement dynamics; (iv) test a predictive model of informal growth using a hybrid framework that embeds the compact city and vulnerability theories; and (v) generate policy-relevant indicators for climate-adaptive urban planning. The methodology adopts a mixed-methods research design combining quantitative geospatial analysis with qualitative insights. The population comprises all informal settlements in the metropolitan region of Lagos, Nigeria, with a target sample of 4,200 households across 38 communities selected through stratified random sampling to ensure representation of floodplains, hillside terrains, and service-poor corridors. Data collection employs (a) remotely sensed Landsat 8/9 imagery (2014–2024) and high-resolution PlanetScope data to delineate informal footprints and land-use change, (b) census and housing records for demographic and tenure variables, (c) structured household surveys (n=1,200) to capture vulnerability, livelihood strategies, and access to services, and (d) semi-structured interviews with 40 key informants spanning municipal planners, community leaders, and NGO staff. Instrument validity is established via pilot testing and triangulation with municipal land registry and cadastral data; reliability is assessed with Cronbach’s alpha for survey scales (target ?0.7). Data analysis employs (i) spatial econometric modeling (Spatial Durbin and Geographically Weighted Regression) to assess how climate exposure metrics (flood depth, heat index, rainfall variability) predict informal expansion while controlling for governance quality and service proximity; (ii) Markov chain and cellular automata simulations to model temporal evolution of informal settlements under varied climate scenarios; (iii) thematic analysis of interview transcripts to extract drivers and coping strategies, and (iv) integration of quantitative and qualitative results through a convergent parallel design to validate the framework. The theoretical base integrates the Vulnerability Theory, the Informality and Formality Continuum, and the Urban Political Ecology perspective, culminating in a novel Spatial Evolution Model that explicates the feedbacks between climate stress, informal land-use change, and urban governance. Expected findings include (i) evidence that climate stress intensifies informal densification in service-scarce zones and accelerates expansion along canal and flood-prone corridors; (ii) quantifiable thresholds where exposure, tenure insecurity, and limited service access synergistically trigger relocation and peripheral growth; (iii) validation of a predictive model showing higher informal growth under combined flood and heat stress, moderated by governance indicators and land tenure reforms; and (iv) a set of policy indicators for climate-responsive informality management, including targeted service provision, risk-based land-use zoning, and community-led relocation protocols. The study contributions to knowledge are threefold (i) theoretical advancement through a spatially explicit framework that links climate stress to informal evolution within an urban political ecology lens; (ii) methodological innovation by integrating advanced spatial models with qualitative insights to predict informal outcomes under climate scenarios; and (iii) practical guidance for urban planners and policymakers in designing climate-adaptive interventions that balance resilience, equity, and tenure security. The conclusion anticipates that climate stress substantially shapes informal spatial trajectories, but governance quality and service provisioning can attenuate adverse patterns. Recommendations emphasize (a) embedding climate risk into formal land-use planning and regularizing tenure for at-risk communities, (b) expanding adaptive service delivery in flood-prone corridors, (c) deploying predictive governance dashboards based on the Spatial Evolution Framework, and (d) sustaining participatory mechanisms to co-create relocation and resilience strategies with affected residents.