Urban Sprawl, Sustainability, and Housing Affordability Trade-offs in African Cities: A Panel SEM Analysis of Nigeria, Ghana, and Kenya

The effects of cities' expansion on sustainability, housing affordability, and carbon emissions are critical for formulating effective policies. This study examines the relationships between urban expansion and key outcomes such as CO₂ emissions, green space, and housing price-to-income ratios in cities in Nigeria, Kenya, and Ghana. Standardized data on multiple urban indicators were analysed using linear regression, mediation analysis, and structural equation modelling (SEM) to separate direct and indirect effects. Regression results indicate that urban expansion increases CO₂ emissions and affects housing affordability, while built-up area and economic factors moderate these effects. Mediation analysis shows that infrastructure spending partially explains the effect of urban expansion on green space, though its impact on CO₂ emissions and housing affordability is limited. SEM confirms these findings, demonstrating strong explanatory power for CO₂ emissions and housing affordability and revealing interconnections between environmental and social outcomes. The study shows that rapid urban expansion can intensify environmental degradation and housing challenges, but targeted infrastructure investment can help mitigate these risks. These results provide empirical evidence to guide urban planning policies aimed at balancing growth, environmental sustainability, and housing affordability.