The Phoenix area is seeing an increase in heat-related deaths, but that's not the case in southern Arizona.
Maricopa County Health officials recorded 172 deaths from heat exposure in 2017, an 11 percent increase from the year before. Global climate change is driving temperatures upward, but so is a purely local phenomenon, the "urban heat island" produced by a concentration of concrete and asphalt.
Tucson also experiences the heat island effect, but with its higher altitude and lower temperatures, heat deaths are less common here. The Pima County Medical Examiner, which serves 11 Arizona counties, doesn't list heat deaths separately, but the office's annual report lists 61 deaths from exposure to the elements in 2016, falling to 37 in 2017. That's nearly a 40 percent drop.
Medical Examiner Greg Hess is working to find exactly how many people died from heat-related causes in the region, to see whether the trend here parallels the one in the Phoenix area.
The Arizona Republic reported Monday that Maricopa County public health officials recently revised the number of heat-related deaths for 2017 to 172.
The initial tally was 155.
Phoenix officials have been tackling the heat island issue by planting trees and promoting lighter-colored asphalt and other reflective construction materials.
Health officials say there have been 18 confirmed heat-related deaths this year. But 128 deaths remain under investigation.
The Associated Press contributed to this report.