How cities can integrate climate risk and resilience
Cities and urban areas face growing climate risks, but risk is not determined by the severity of a hazard alone. It also depends on who and what is exposed, which populations might be particularly sensitive, and whether communities have the resources and capacity to respond. Our publication, A Framework to Integrate Climate Risk and Resilience: A Case Study on Heat, aims to connect these dimensions more clearly to move from measuring exposure towards identifying opportunities for action and to build resilience.
The framework was developed by reviewing academic and practitioner literature on climate risk, population vulnerability, as well as existing resilience and heat vulnerability indices. We examined how studies define key concepts, assign indicators to various risk dimensions, and then combine them into composite measures. We also considered whether the underlying data and methods could be applied consistently across cities with very different climates, development levels, governance arrangements and data availability.
Urban heat provides a useful case study because its impacts emerge through the interaction of several factors. Air temperature and relative humidity are important, but the underlying built environment also matters. An individual's housing, accessing to cooling, underlying health conditions, working conditions and individual behavior also matter.
Within the heat vulnerability index (HVI) literature, two main conceptual frameworks are used, the Population Vulnerability Equation, which generally combines exposure, sensitivity, and adaptive capacity, and the Risk Triangle, which conceptualizes risk through the interaction of hazard, exposure and vulnerability. While many papers use one or the other of these frameworks, the ways in which they operationalize the variables differ considerably, leading to a lack of consistency both within and between studies. In addition to variability in how indicators are chosen and categorized, the methods of combining, scaling, and weighting variables differ considerably from study to study. Other challenges, such as the omission of local community assets and a lack of relevant data, also hinder the effectiveness of HVIs. Finally, vulnerability to heat depends on context specific factors, such as the availability of air conditioning, climate zones, and social/behavioral norms. This variation presents a challenge in designing a one-size-fits-all framework for global cities with different climates, developmental stages, and sizes.
Our conceptual framework aims to fill some of these gaps by explicitly including both active and dormant community assets, emphasizing the policy levers that could work to activate dormant assets when fully utilized. Additionally, we use recent advances in our understanding of urban heat, including new livability and survivability metrics, as well as state-of-the-art remote sensing data, to estimate the potential risk of urban heat exposure.
