Coproducing Opportunities to Advance Extreme Heat Resilience in Southern Arizona

Extreme heat events in the U.S. Southwest have become more frequent, longer, and intense over the last few decades (EPA 2023; USGCRP 2023), mirroring global patterns (IPCC 2023; Perkins-Kirkpatrick and Lewis 2020) and endangering the health of people and ecosystems (UNDRR 2020). In Southern Arizona, consisting of counties centered around Tucson Metropolitan Statistical Area (Pima County), heat-related fatalities have steadily increased over the last decade. In Pima County alone, heat-related fatalities reached a record of 176 in 2023, having disproportionately higher impacts on heat-stressed vulnerable groups like unhoused populations, undocumented migrants, and outdoor workers (Pima County Office of Medical Examiner 2023). Heat hazards will continue to magnify due to climate change. Under the high greenhouse gas emissions scenario, the number of days with temperatures higher than 100°F in Pima County is projected to rise to 182 days, i.e., half of the year (USGCRP 2023). These escalating risks and compounding impacts on sensitive desert habitats, water security, air quality, and wildfire likelihood (USGCRP 2023) underscore the importance of local action.