Journal of Extreme Events

Barriers to the application of climate science in land use planning are often understood as a problem related to perceived disciplinary knowledge gaps. This paper argues that, instead, limitations to the application of knowledge are not strictly linked to transference, but are also attributed to the thought processes that planners use to understand and use information. This study uses an interactional co-production framework from Science and Technology Studies (STS) to explore these processes in the context of heat response planning in Chatham County, Georgia, in the United States: a coastal county exposed to hot and humid conditions that render its population, particularly its growing elderly and low-income, vulnerable to heat health risks. We specifically focus on the processes used by planners during a heat response planning workshop, exploring the discussions and actions taken to develop a plan. We attempt to answer the following questions: What are the processes used by planners to respond to climatic issues such as heat vulnerability? How do these processes determine the application of the scientific knowledge produced? How does this process enable or limit the use of climate knowledge in decision making at the city scale? This paper argues that planners engage in three steps to determine the applicability of climate knowledge to urban planning: (1) using their own experiences to contextualize and visualize the information in their community, (2) being extremely cautious about the use of information because of a fear of failure, and (3) asking for specific policies to be in place to justify and legitimate actions and promote projects throughout the city. Using these insights, this paper concludes with some thoughts on how climate knowledge might be better integrated into urban planning.

We tested mediation models using structural equation modeling (SEM) to better understand the pathways that lead to negative heat-health outcomes for socially vulnerable households and individuals in Phoenix, AZ. Extreme heat presents a significant risk to public health, and current theories of social vulnerability cannot explain the mechanistic pathways that lead to negative health outcomes. A better understanding of these pathways can be used to target more effective public health interventions. We find that self-reported indoor thermal discomfort was a strong and significant predictor of indoor heat illness outcomes (Std $\mathrm{\text{B}}=0.72$, $p<0.01$), suggesting that heat risk messaging could encourage the public to trust their personal sense of being too warm. Thermal discomfort (Std $\mathrm{\text{B}}=-0.28$, $p<0.01$) and self-reported indoor heat illness (Std $\mathrm{\text{B}}=-0.47$, $p<0.01$) were only predicted by socioeconomic status (SES); age, gender, and racialized group did not relate to heat illness or thermal discomfort based on our sample. However, specified mediators did not fully explain the relationship between SES and thermal discomfort or heat illness, suggesting that we do not fully understand how social vulnerability manifests as negative heat-health outcomes. In addition, results show that passive cooling techniques, like taking a cold shower, did not have a protective effect on heat-health outcomes, and these passive cooling behaviors were used in greater proportion by socially vulnerable individuals. This study concludes with 11 evidence-based hypotheses about how social vulnerability may produce negative heat-health outcomes.

Addressing the urban heat island effect is critical in mitigating the threat of heat from the perspective of land use planning and design. This paper, therefore, presents a structured review of urban heat island mitigation policy that is contained in the local-level planning policy documents and regulation of 20 large municipalities throughout the United States and Canada. It explores how the issue of the urban heat island effect is framed and approached and, therewith, facilitates an understanding of how aware municipalities are of the issue and its impacts. The review identifies a total of 307 instances of mitigation policy measures among 19 of the 20 municipalities, with the most commonly applied: approaches to mitigation being the promotion of latent heat flux, albedo modification, and provision of shade cover; and, framing contexts being public health, air quality, energy, comfort, and climate change. Although the review indicates that there is widespread awareness of the issue, it notes that only 79, or 25.7 percent, of the 307 mitigation policy measures were framed in any context. Thus, the majority of policy measures do not communicate an understanding of the significance and potential impacts of the urban heat island effect or provide a lens through which it should be perceived and, therewith, addressed. Indeed, they call for blind action. This suggests a need to promote awareness of the potential impacts of the urban heat island effect and communicate same in local planning policy documents and regulations.

Understanding how people perceive the risks of extreme heat is an essential part of developing better risk communication strategies and ultimately reducing vulnerability to heat. This study analyzed how tourists perceive and respond to extreme heat while recreating on public lands in southeastern Utah, a hot and dry environment. An increasing number of tourists are visiting national parks in the southwestern United States, exposing more people to heat-related health risks. This investigation focuses on how geographic differences of origin and thermal perceptions are associated with risk perceptions of extreme heat, and how risk perceptions in turn are associated with protective behaviors. This study found that risk perceptions of extreme heat were not significantly associated with demographic differences or the geographic origin of respondents. This study did find that while visitors could accurately predict the air temperature, on average within 1.1^∘C (2^∘F) of the actual temperature, visitors’ risk perception of extreme heat did not increase as temperatures increased. This study also found that visitors with higher risk perceptions were more likely to have engaged in certain protective behaviors — such as checking the weather conditions before their hike — but not others, such as the amount of water they carried. By understanding how people perceive and respond to the hazard, we can better understand best practices for communicating the risks of extreme heat with the intent of saving lives. These results are intended to help tourist agencies, emergency and natural resource managers and planners, and policymakers in creating and improving communication strategies for extreme heat.

Extreme heat is a growing concern for cities, with both climate change and the urban heat island (UHI) effect increasingly impacting public health, economies, urban infrastructure, and urban ecology. To better understand the current state of planning for extreme heat, we conducted a systematic literature review. We found that most of the research focuses on UHI mapping and modeling, while few studies delve into extreme heat planning and governance processes. An in-depth review of this literature reveals common institutional, policy, and informational barriers and strategies for overcoming them. Identified challenges include siloed heat governance and research that limit cross-governmental and interdisciplinary collaboration; complex, context-specific, and diverse heat resilience strategies; the need to combine extreme heat “risk management” strategies (focused on preparing and responding to extreme heat events) and “design of the built environment” strategies (spatial planning and design interventions that intentionally reduce urban temperatures); and the need for extensive, multidisciplinary data and tools that are often not readily available. These challenges point to several avenues for future heat planning research. Ultimately, we argue that planners have an important role to play in building heat resilience and conclude by identifying areas where scholars and practitioners can work together to advance our understanding of extreme heat planning.

Climate change will impact cities’ infrastructure and urban dwellers, who often show differentiated capacity to cope with climate-related hazards. The Shared Socioeconomic Pathways (SSPs) are part of an emerging research field which uses global socioeconomic and climate scenarios, developed by the climate change research community, to explore how different socioeconomic pathways will influence future society’s ability to cope with climate change. While the SSPs have been extensively used at the global scale, their use at the local and urban scale has remained rare, as they first need to be contextualized and extended for the particular place of interest. In this study, we present and apply a method to develop multi-scale extended SSPs at the city and neighborhood scale. Using Boston, Massachusetts, as a case study, we combined scenario matching, experts’ elicitation, and participatory processes to contextualize and make the global SSPs relevant at the urban scale. We subsequently employed the extended SSPs to explore future neighborhood-level vulnerability to extreme heat under multiple plausible socioeconomic trajectories, highlighting the usefulness of extended SSPs in informing future vulnerability assessments. The large differences in outcomes hint at the enormous potential of risk reduction that social and urban planning policies could trigger in the next decades.