This interdisciplinary research project explores human-ecosystem-climate interactions at the neighborhood scale in metropolitan Phoenix. The project draws upon social and ecological theories of spatial heterogeneity in cities in order to understand how urban development leads to economic, social, and physical inequalities among neighborhoods, which in turn produce neighborhood differences in microclimate conditions. Microclimate conditions influence the biotic environment, which then completes the cycle by influencing the socioeconomic and physical systems of neighborhoods. Because neighborhoods have unequal resources for responding to climate stress, socioeconomic status of the neighborhood and other local characteristics will moderate the effects of this process. The research has three specific objectives. First, the project will show how the settlement of neighborhoods between 1970 and 2000 transformed the landscape by altering land use, land cover, and climate. Second, the project will demonstrate whether and to what extent the resulting differences among neighborhood microclimates expose humans and other biota to unequal levels of climate-induced stressors, such as heat, poor air quality, and storm hazards. Third, the project will investigate the resilience of human and plant communities in neighborhoods that have unequal amounts of capital to cope with climate stress. The research sites are seven Phoenix neighborhoods located at monitoring sites of the Central Arizona-Phoenix Long-Term Ecological Research project.

The neighborhoods, bounded by census block groups, included cases that varied by age, distance to urban center, land cover, income, and ethnic composition.The project used data from a wide variety of sources, including the census, social surveys of residents, historical land-use surveys and climate records, field measures of environmental conditions, and remotely sensed images of land cover and temperature. GIS mapping, graphing tools, spatial statistics, and multivariate statistical analysis were used to develop indicators of human, ecosystem, and climate activities and changes over time using. Using key indicators, neighborhood socioecological cycles were compared for places that differ by social class, physical features, and distance from the urban center. Research results were disseminated through publications in several disciplines and presentations at professional meetings.

Research on urban development in arid regions contributes to understanding the regional dimensions of global climate change. This project advanced the development of integrative theory in the social and ecological sciences by explaining how human actions influence climate change at the neighborhood scale. This is a necessary link between fine-scale ecosystem processes, such as variation in neighborhood microclimates, and coarse-scale environmental phenomena, such as global warming. The research helped improve models of urban growth and models of regional climate change. The project also informed human vulnerability theory, which explains how social inequalities expose poor people to higher risks of environmental hazards. While many studies of vulnerability focus on "natural" disasters that are more likely to harm poor people, this project studied chronic environmental conditions, specifically climatic variability and change, which poses a more lasting but less obvious threat to vulnerable populations. This project also provided opportunities for undergraduate and graduate students to participate and learn about the interface between science and public issues as well as the conduct of interdisciplinary research.