Urban vulnerability assessment of the coast of Chile

Vulnerability to weather-related hazards is a considerable humanitarian, economic and environmental concern for cities, especially in developing countries. However, there is a limited understanding of urban vulnerability and its specific implications. This study assesses the spatio-temporal vulnerability caused by climatic and societal change in Chile’s key coastal urban areas. In this urban vulnerability assessment, both regional and local approaches were undertaken, the former to give a broad sense of the possible futures that these cities face and the latter to explore, using all available and reliable data, how climatic and societal change affected one of these metropolitan areas. For the time points 2025, 2055 and 2085, the regional assessment shows that vulnerability is likely to vary across different scenarios and time frames. A significant future increase in exposure to hazards is mainly moderated, to a greater or lesser extent, by an increase in the adaptive capacity of the cities in question. Cities in central and southern Chile are more vulnerable. The local assessment provides a detailed evaluation of recent past vulnerabilities in the Concepción Metropolitan Area (CMA). In the local assessment, an urban indicator framework was first designed and then employed to explore changes in exposure and sensitivity of areas within CMA and the general ability of the urban system to adapt to different hazards. Five weather-related hazards were explored: coastal flooding, fluvial flooding, water scarcity, heat stress and wildfire, using a flexible methodology based on spatial fuzzy modelling with geographic information systems. Hazard-specific vulnerability and overall vulnerability indices were created. The local assessment results indicate a high vulnerability in the CMA that decreased slightly between 1992 and 2002. The combined socio-economic factors of sensitivity and adaptive capacity influenced the index more than the biophysical factors of exposure. Changes in age structure and economic growth had a greater influence on vulnerability that other variables. Overall vulnerability varied across municipalities and hazards, with wildfires and water scarcity influencing overall vulnerability the most. Fuzzy modelling enabled realism and flexibility in the standardization and aggregation of indicators with different attributes. It permitted the exploration of the individual and aggregate influence of the indicators that comprise the indices. ArcGIS software favoured transparency and simplicity in the aggregation of multiple entry criteria, facilitating spatial representation through maps, which can help identify indicators, components and hazards or combinations thereof that influence municipal vulnerability. The results can be used to improve and promote dialogue among policy-makers and stakeholders regarding the prioritization of resources for urban development in ways that can reduce vulnerability to climate change.