Why do citizens evacuate, and where do they go? Evacuation is an important aspect of mitigating the costs of climate-change induced disasters to human life, but many cities struggle to achieve high rates of evacuation, especially among vulnerable residents. Using Facebook data aggregated to the neighborhood level, this mixed methods study analyses the movement of Facebook users to and from cities struck by storms and floods. I examine why evacuation varied among cities during Hurricane Dorian, a major hurricane which struck the US southeast in 2019. This study examines the local political drivers of evacuation, including the intersecting roles of evacuation orders, policy tools, bonding, bridging, and linking social capital, and social vulnerability. I combine mobility network analysis and geographic information systems with statistical matching models and case studies of affected communities. This study highlights how linking social capital and “soft” community-oriented preparedness policies boosted evacuation between cities, while bonding social capital was associated with less evacuation. By clarifying the role of community level factors in evacuation, this study aims to open a research agenda for analyzing the politics of human mobility during crisis.

This study examines why some communities are more vulnerable than others,focusing on the transformative effect of residents’ social capital on changing levels of vulnerability over time. We examine the case of Japan, the third largest economy in the world. Japan faces dozens of earthquakes, floods, and typhoons each year, but some communities are more socially vulnerable in the face of disaster than others. Drawing on difference-in-differences models and matching experiments, we test the effect of bonding, bridging, and linking social capital on vulnerability. We find that controlling for cities’ governance capacity, resource demand based on population, and damage from recent hazards,the level of bonding social capital in a community leads to lower levels of vulnerability. However, other types of social capital do not immediately lead to lower vulnerability, implying that greater government support is necessary in these cases.

Over the past thirty years, disaster scholars have highlighted that communities with stronger social infrastructure - including social ties that enable trust, mutual aid, and collective action - tend to respond to and recover better from crisis. However, comprehensive measurements of social capital across communities have been rare. This study adapts Kyne and Aldrich’s (2019) county-level social capital index to the census-tract level, generating social capital indices from 2011 to 2018 at the census-tract, zipcode, and county subdivision levels. To demonstrate their usefulness to disaster planners, public health experts, and local officials, we paired these with the CDC’s Social Vulnerability Index to predict the incidence of COVID-19 in case studies in Massachusetts, Wisconsin, Illinois, and New York City. We found that social capital and social vulnerability predicted as much as 95% of the variation in COVID outbreaks, highlighting their power as diagnostic and predictive tools for combating the spread of COVID.

Abstract: Rising partisan polarization in the American public over the last decade has been linked to stress and anxiety, raising questions about how communities and public health experts should respond. As the strength of an individual’s social network has been linked to better health outcomes, could building a diverse set of connections moderate the effect of political polarization on an individual’s health? This study examines the role of social capital as a key intervening variable in the relationship between polarization and health. Drawing on a nationally-representative survey of 2,752 US residents conducted in December 2019 compared with county level data, we use negative binomial, logit, and gamma models to examine the interaction between indicators of political polarization and bonding, bridging, and linking social capital on physical and mental health outcomes. We find consistent evidence that bonding social ties intervene to improve the physical and mental health of individuals in polarized communities, while bridging ties are related to worse health for politically isolated residents. By highlighting the relationship between polarization, social networks, and health, our findings shed light on how public health experts, and policymakers can improve health outcomes in polarized communities.

Recent studies have linked the strength and type of social ties in communities to abating the spread of COVID19. However, less attention has gone to social infrastructure, the places in neighborhoods that foster social ties and connectedness. This study highlights the role of social infrastructure in COVID-19 outcomes in Fukuoka, a major city in Southwestern Japan, drawing on mapping, modeling, and statistical simulations. I find that city blocks in Fukuoka with more social infrastructure see lower rates of COVID spread, even after controlling for social capital, vulnerability, and health care capacity. However, some kinds of social infrastructure are more beneficial than others; parks, libraries, and public educational sites are linked to lower rates of infection, likely because social distancing is easier here, while public meeting facilities, community centers, and schools are linked to rising infection, likely because these places may facilitate transmission through gatherings. City officials should carefully inventory the amount of social infrastructure in their neighborhoods and prioritize expanding outdoor social infrastructure during and after the COVID-19 pandemic, where risk of transmission is lower.

Why do some cities adopt more renewable energy than others? This mixed methods study examines the effect of linking ties between companies and mayors, to quantify the effect that a well connected city mayor can have on their city's renewable energy transition. We draw on the case of sizable cities (at least 30,000 residents) in the US states of Massachusetts and the Japanese prefecture of Chiba. We catalogue instances of mayoral support for renewables and specific companies over the last ten years drawing from online newspapers and government documents, statistical modeling, and case studies of key mayors. Mayoral support and ties to renewable power greatly improve solar adoption, but that the strength of grassroots social capital in these cities can strengthen or shackle mayors' efforts, depending on the type of social capital. By highlighting the role of mayors in renewable energy, we hope to clarify in what situations mayors can make a difference in helping cities transition to renewable energy.