Effects of urban development on future multi-hazard risk: the case of Vancouver, Canada

Disaster risk reduction should anticipate how future natural hazard risk would be influenced by changes in urban vulnerability. This paper investigates the effect of one key driver of change, urban development. It models current and future risk for the year 2041 in a rapidly growing urban area, Vancouver, Canada, from both earthquake and coastal flood hazard. Three urban development futures are considered—status quo, compact, and sprawled development—that differ in the housing stock configuration used to accommodate an identical, projected increase in population and dwellings. Results indicate that while exposure is expected to increase substantially in future, the implications for risk vary greatly between hazards and impact types. For earthquake, population increase is attenuated by improvements in the building stock, whereas for flooding, disaster impacts increase at a much higher rate than population growth. Overall, disruption impacts are more sensitive than damage to changes in population and development. The effect of urban development on future risk is not unidirectional, but depends upon hazard type, impact type, and degree of climate change. None of the development futures is consistently best from a risk perspective, but along many dimensions, compact development yields more severe disaster impacts relative to status quo development. The findings underscore the importance of considering natural hazard risk in urban development planning, and of recognizing the inherent differences between hazards and impact types in this planning.