Urban Growth – Understanding the Dominant Drivers and Spatial Dynamics of Risk

Abstract

Asian cities located in deltaic settings such as Ho Chi Minh City (HCMC) exhibit high exposure to flood risk due to their location, low elevation, and, in tropical regions, significant annual climatic extremes. Adaptation and disaster risk management in such contexts must focus on minimising exposure and reducing vulnerability by strengthening urban resilience. Geographic factors determine biophysical exposure, which can be influenced by spatial planning and construction technology, while social vulnerability is shaped by population density, income, education, risk awareness, and institutional capacity. Effective spatial planning should address both exposure and vulnerability through place-based risk assessments. Key impact and vulnerability indicators vary across and within megacities, with location, urban form, building types, socio-economic conditions, and governance capacity all affecting risk. Exposure and vulnerability are dynamic, shaped by rapid urbanisation and socio-economic change. Risk assessments have often overestimated climate extremes by neglecting non-climatic drivers such as urbanisation. The HCMC case study highlights the urgent need to integrate future urban development dynamics into scientific methods and datasets, enabling a better understanding of the relative importance of non-climatic and climatic drivers in shaping urban risk.