Residents of the United States increasingly support organic and local food systems. New Social Movement theorists have described alternative agriculture as a social movement that transcends social class. Other scholars have critiqued alternative agriculture for catering to a middle-class, white public. Simultaneously, geographers have identified communities across the United States that struggle with reduced access to healthy fruits and vegetables. In some of these neighborhoods, known as “food deserts,” local groups are redefining an inequitable distribution of healthy food as a social injustice, and they have begun initiatives to practice “food justice.” The overarching research questions of this study are: 1) How do communities become food deserts? 2) How do food justice movements crystallize and communities practice food justice? 3) What are the social outcomes of food justice movements? Using an Ecology of Actors framework, this study analyzes the actors and operational scales of three food justice movements in Phoenix, Arizona. A narrative analysis of historical scholarly materials and other artifacts reveals that, for more than a century, some communities have tried to create minority-operated local food systems. However, they were thwarted by racist policies and market penetration of the conventional US food system. Interviews with residents, garden organizers and food justice advocates living and working in the city create a narrative of the present day struggle for food justice. Results of this work show that contemporary residents describe their foodscape as one of struggle, and carless residents rely upon social networks to access healthy food. Garden organizers and gardeners are creating networks of community gardens, market gardens, and informal farmers’ markets. They are actively transforming their communities’ landscapes with sophisticated garden ecology in an intense urban heat island. However, the movement’s continued success may be threatened. Many new Phoenix-based local food coalitions and national alternative agriculture social movements are now working to alter Phoenix’s foodscape. Composed of well-educated professionals, who have adopted a justice-based language around food, these organizations may unintentionally co-opt the local food justice movements.

This dissertation explores vulnerability to extreme heat hazards in the Maricopa County, Arizona metropolitan region. By engaging an interdisciplinary approach, I uncover the epidemiological, historical-geographical, and mitigation dimensions of human vulnerability to extreme heat in a rapidly urbanizing region characterized by an intense urban heat island and summertime heat waves. I first frame the overall research within global climate change and hazards vulnerability research literature, and then present three case studies. I conclude with a synthesis of the findings and lessons learned from my interdisciplinary approach using an urban political ecology framework. In the first case study I construct and map a predictive index of sensitivity to heat health risks for neighborhoods, compare predicted neighborhood sensitivity to heat-related hospitalization rates, and estimate relative risk of hospitalizations for neighborhoods. In the second case study, I unpack the history and geography of land use/land cover change, urban development and marginalization of minorities that created the metropolitan region's urban heat island and consequently, the present conditions of extreme heat exposure and vulnerability in the urban core. The third study uses computational microclimate modeling to evaluate the potential of a vegetation-based intervention for mitigating extreme heat in an urban core neighborhood. Several findings relevant to extreme heat vulnerability emerge from the case studies. First, two main socio-demographic groups are found to be at higher risk for heat illness: low-income minorities in sparsely-vegetated neighborhoods in the urban core, and the elderly and socially-isolated in the expansive suburban fringe of Maricopa County. The second case study reveals that current conditions of heat exposure in the region's urban heat island are the legacy of historical marginalization of minorities and large-scale land-use/land cover transformations of natural desert land covers into heat-retaining urban surfaces of the built environment. Third, summertime air temperature reductions in the range 0.9-1.9 °C and of up to 8.4 °C in surface temperatures in the urban core can be achieved through desert-adapted canopied vegetation, suggesting that, at the microscale, the urban heat island can be mitigated by creating vegetated park cool islands. A synthesis of the three case studies using the urban political ecology framework argues that climate changed-induced heat hazards in cities must be problematized within the socio-ecological transformations that produce and reproduce urban landscapes of risk. The interdisciplinary approach to heat hazards in this dissertation advances understanding of the social and ecological drivers of extreme heat by drawing on multiple theories and methods from sociology, urban and Marxist geography, microclimatology, spatial epidemiology, environmental history, political economy and urban political ecology.

This research is about urban homeless people's vulnerability to extreme temperatures and the related socio-spatial dynamics. Specifically, this research investigates heat related coping strategies homeless people use and how the urban environment setting impacts those coping strategies. Semi-structured interviews were conducted with homeless people in Phoenix, Arizona during the summer of 2010. The findings demonstrate that homeless people have a variety of coping strategies and the urban environment setting unjustly impacts those strategies. The results suggest a need for further studies that focus spatial environmental effects on homeless people and other vulnerable populations.