Climate justice in community design: Investigating alternative metrics of economic vulnerability to extreme heat in Metro Phoenix, Arizona

Vulnerability, which considers exposure, sensitivity to hazards, and adaptive capacity, is frequently assessed using income or poverty levels, neglecting affordability factors in the heat vulnerability index. Heat adaptation strategies, providing legal resources to vulnerable groups, effectively address extreme heat impacts. However, the higher living costs in metro Phoenix's Maricopa County, compared to state and national averages, underscore the limitations of relying solely on US Census poverty estimates of residents' living expenses. The question arises, Who is most affected during extreme heat? what is the relation between household income and cost of living in metro Phoenix areas by considering their vulnerability to extreme heat? This paper introduces an alternative economic vulnerability metric--Household Expenditure and Income Gap Highlighter Tool (HEIGHT) developed as a joint effort between Arizona State University Knowledge Exchange for Resilience and the Valley of the Sun United Way to measure and visualize the true costs of living at the neighborhood scale. This tool highlights the emerging gap between household income and living costs by counting for food, housing, health care, childcare, and utilities expenses. The HEIGHT tool’s results as an adaptive capacity index reveal the true cost of living in each county and neighborhood, emphasizing the disparity between household income and living expenses. We examine regional spatial variation and vulnerability clustering in metropolitan areas by using Geographic Weighted Regression (GWR), which reveals high vulnerability clusters around city centers. This study highlights the need to use alternative methods, beyond Census poverty data, for more accurate socio-economic vulnerability assessment, addressing income and living cost disparities. Recognizing socioeconomic factors is vital for landscape architects and urban designers to integrate economic vulnerability, affordability, and climate justice in community-based nature-focused solutions for climate change resilience.