Strength in numbers: A guide to urban resilience
Wamsler, C., and E. Brink. 2014. Moving beyond short-term coping and adaptation. Environment and Urbanization 26(1): 86-111.DOI: http://dx.doi.org/10.1177/0956247813516061
Urban centers simultaneously create and mitigate vulnerability during natural disasters. The social, economic, and environmental factors that determine where an urban center falls along the wide spectrum of least to most vulnerable are poorly understood. Given that the United Nations projects more than 90 percent of future population growth to be absorbed by urban centers in developing countries, understanding what determines an urban center's degree of vulnerability is critical for future improvements in resiliency to natural disasters.
Through a review of the disaster risk reduction literature, the study identifies several means of increasing resilience through reducing vulnerability. The "vulnerability" of a system is commonly thought of as the combination of its exposure, sensitivity, and adaptive capacity. Thus, urban centers can reduce their vulnerability through improvements in any or all of the exposure, sensitivity, and adaptive capacity categories.
Numerous options to reduce exposure and sensitivity, and increase adaptive capacity, are given: diversification of income, improving family members' education levels, or reorganizing the layout of one's home. Additionally, effective options for disaster-specific resilience are given: attachment of furniture to the floor in earthquake prone areas, recycling waste water in drought prone areas, or constructing water drainage points in houses for flood prone areas.
After mapping out numerous strategies for reducing vulnerability and improving communities' abilities to respond to disasters, the authors identify two essential attributes of the most effective strategies – flexibility and inclusiveness. Accordingly, coping mechanisms such as improving educational status or diversifying income may prove more flexible and inclusive than "hard" coping mechanisms such as physical changes in infrastructure. For example, diverse incomes allow urban residents to respond to a wide range of natural disasters in the best possible way given event-specific challenges.
The conclusion of the study mirrors the notion that ecological resilience is a result of niche redundancy. The idea of niche redundancy suggests that multiple species may be capable of performing essential functions within natural ecosystems. For example, two or three species of tree providing suitable habitat for a desirable bird species identifies a resilient ecosystem in the most fundamental sense. If one species of tree disappears from the area, others tree species may persist and continue to support the bird population. Similarly, the number of responses available to an urban society faced with a disaster may ultimately determine its degree of resilience.
Although the study notes that little data exists for urban residents' coping strategies, it also recognizes coping strategy's utility for informing transformation pathways to more resilient urban societies. Strategies such as improving learning mechanisms, facilitating transfer of knowledge, or offering alternative coping strategies to existing ones will likely strengthen portfolios of response options to natural disasters.
While the intensity and frequency of future natural disasters are projected to increase under climate change models, the specifics of precisely how they will do so remains uncertain. Thus, establishing fluid and constantly-evolving coping mechanisms that increase, or at least maintain, the number of coping strategies available to urban residents will likely trump static uses of currently effective strategies.