Pima County’s heat deaths have surged at an unprecedented rate over the past two years, coinciding with a sharp rise in prolonged summer heat. That worrying trend brings the number of Pima County heat deaths to a similar rate as Maricopa County’s, despite the north county being hotter.
That’s according to a report, published Aug. 8, 2024 by Making Action Possible for Southern Arizona, which examined temperature data from the National Weather Service and death data from the Maricopa County Department of Public Health and the Pima County Medical Examiner’s Office. Researchers with the University of Arizona modeled the relationship between daily median temperatures and heat-related deaths to estimate how temperature changes impacted deaths.
Many people most affected by heat, the report notes, have multiple factors in their lives that make them more susceptible to high temperatures, including drug use, unstable housing and the stigma that comes with both.
“Social isolation has also worsened by many measures,” the report warns.
In those findings, Pima County saw a startling rise in heath-related deaths in recent years. So did Arizona: the report says state-wide heat-related deaths increased tenfold in 20 years.
Heat deaths are rising in Pima County
Pima County saw 126 heat-related deaths in 2023, a number that does not count 50 heat-related deaths of undocumented people crossing the border with Mexico.
The deaths caused directly by heat, rather than just where heat was a related element, grew sharply.
There were 50% more heat-caused deaths in Pima County in 2023 than in 2022, and more than double any year before 2022. In total, 43 people died from heat-caused deaths in Pima County in 2023 and 28 died in 2022, the report said.
Even adjusting for population growth in Pima County (about 8.5% since 2010) the report found the death rate in 2023 was still several times the rate in most previous years.
“More people tend to die on hotter days, and summers have gotten longer and hotter as a result of both global climate change and local urban heat island effects,” the report says.
Tucson may have warmed more than Phoenix since 2001, according to the report’s analysis.
The report would characterize the increase in heat deaths as a pattern of exponential growth.
Of the victims in 2023, nearly three-quarters were men; 70% were over 50; more than half had chronic health conditions. Racial minorities were overrepresented among the victims as well, the report said.
Despite lower temps, Pima County’s heat-death rate matches Maricopa’s
Pima County has less than a quarter of the population of Maricopa County, but a proportionately similar number of heat deaths. In 2024, Maricopa had 140 deaths per million people, while Pima had 118 deaths per million people.
“Pima County (Tucson) had a death rate almost as high as Maricopa County, despite the fact that summer in Tucson averaged seven degrees cooler than Phoenix,” the report said. “This suggests that Pima County’s population is much more vulnerable than Maricopa County’s population.”
The reason for that wasn’t clear, but possible reasons could be that Pima County had a higher rate of unsheltered people and people with lower incomes. A recent University of Arizona report found roughly 16,000 households (or 11% of renters) in Pima County struggled to make rent in 2023.
Another possibility was that residents in Maricopa County were more acclimatized to hotter summers, whereas Pima County residents were dealing with a sudden spike, the report hypothesized.
Still, the unmistakable trend in both Maricopa and Pima is hotter, and therefore deadlier, weather.
Housing, homelessness a key factor in heat deaths
Heat deaths for unhoused communities have gone up as the number of people living outside has gone up. Before 2019, Pima County had a stable — and at points even declining — number of unhoused people. From 2013 to 2019, there was no clear increase in heat-caused deaths, the report said.
Then in 2020, more people began living on the streets and heat-caused deaths began to rise as housing prices reached an all-time high. The report says that being unsheltered exposes an individual to 200 to 300 times the risk of heat-related death.
Being outside, and having ingested either methamphetamine, fentanyl or both, also increased a person’s vulnerability to heats.
In 2023, more than 60% of heat deaths in Pima County took place outside. Of the heat-related deaths in Pima County, 40% were of people who ingested methamphetamine, fentanyl or both. That comes as overdose deaths doubled in the past decade, the report said, “indicating more widespread and/or intense usage and addiction.”
What can be done?
Heat-death solutions intersperse with other areas of social concern, says the report. Reducing housing costs means fewer people will live on the street. Similarly, reducing the urban heat island effect, where cities are hotter because buildings and roads absorb and maintain heat, will limit the number of people who go into emergency rooms for heat-related sickness or who are not able to exercise regularly in the summer.
Some of the work toward more walkable infrastructure needs to happen at the state level, but localities are making moves toward changes that could also help reduce the impact of heat.
The report suggests reducing parking spaces tied to new development to cut down on the amount of hot asphalt in a city. In Tucson, the planning department is putting forward a new zoning approach, called the Community Corridor Tool, they say will encourage denser development.
Cities can also invest in trees to cool down the outside, and more shelter beds to keep people inside, the report says. Tucson has moved toward both, with the recent introduction of a Community Forest Action Plan and plans to open a new low-barrier emergency shelter this spring.
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