Climate change, urbanization spur scorching Phoenix heat wave

Jerod MacDonald-Evoy

(Arizona Mirror) Phoenix is close to breaking a record streak for consecutive days with high temperatures at or above 110 degrees, and the heat will continue to become more enduring as urbanization grows and the impacts of climate change continue.

“You can’t argue that we are definitely seeing that warming climate,” Phoenix National Weather Service Meteorologist Issac Smith told the Arizona Mirror. “This is becoming more frequent.”

In the early 1900s, the Greater Phoenix area only experienced approximately five days per year that reached 110 degrees on average, as compared to the 27 it has typically seen from 2011 onward, according to State Climatologist Erinanne Saffell.

“It is five times what it was in the early 1900s,” Saffell said.

The existing all-time record for consecutive days with a high at or above 110 degrees was set in 1974 — at 18 days. Current predictions have this year surpassing that record. The previous three years — 2020, 2021 and 2022 — are all in the top 10 for the most consecutive days with temperatures at or above 110.

The current heat wave is caused by an area of high pressure that has stayed over the area for several weeks that will continue to build over the weekend, leading to even higher temperatures, according to Smith. That high pressure leads to less moisture in the atmosphere.

Overall temperatures have been rising across the globe, contributing to what we are seeing in Arizona. The global temperature has risen by approximately 2 degrees Fahrenheit since 1880, but in Phoenix you can add another 5 degrees to that number, according to Saffell.

That is due to the urban heat island effect.

The urban heat island effect is when the temperatures in an urban area increase due to the heat the area retains, mostly due to heat-retaining structures and ground coverings, lack of vegetation and other impacts of urbanization.

This effect can have a swirl of consequences, such as a city temperatures not cooling at night, leading to residents “cranking their air conditioners” after sundown, which then drains energy usage and strains systems, according to Saffell. Asphalt can heat up to 180 degrees, which is then retained in the air.

“While we may have once viewed heatwaves as random annoyances, it’s becoming impossible to deny that they are getting hotter, longer, more frequent, and more deadly at an alarming and unnatural pace,” said Mel Smith, spokesperson for 350 US, an organization that aims to address climate change and transition to renewable energy. “In extreme heat, air conditioning becomes even more essential, which overburdens our unstable power infrastructure, and increases the risk of power outages — which studies estimate could send half of Phoenix to the emergency room.”

Arizona isn’t the only place experiencing this type of heat. California and much of Europe are also experiencing record breaking heat, causing groups like 350 to take notice.

“Unfortunately, heat waves are only one type of extreme weather caused by climate change, and it is rendering whole regions of our planet increasingly less livable,” Mel Smith said. “The good news is there’s still time to prevent things from getting even worse: we can end the era of fossil fuels and invest more resources in a swift and just transition to renewable energy.”

Saffell says that efforts to install “cool pavement” that lowers the average temperature of the asphalt is one solution to helping minimize the impacts of the heat island effect, but other solutions like additional shade structures and planting desert-friendly trees could also have direct impacts.

Meanwhile, the heat is already having deadly consequences for some of the most vulnerable.

Twelve people have died from heat related causes in Maricopa county so far this year, with half of them being reported to be unhoused, according to reporting by the Arizona Republic. Those 12 are the first confirmed deaths, but there are 55 still under investigation that are suspected to have been caused by the heat.

“A lot of people in Arizona are like ‘it is July, it is hot, it is the desert,’” NWS Meteorologist Issac Smith said. “[Heat] is the number one weather-related killer in the United States.”

There is some hope though, according to Smith and Saffell.

The extreme heat can hopefully spawn some moisture, eventually.

Arizona is currently in the middle of its monsoon, which runs from June 15 through Sept. 30, however, this season has been particularly dry. According to Issac Smith, next week Arizona may start to see some of that monsoonal moisture begin to rear its head. The extreme heat is sometimes necessary to spur the moisture into action, Saffell said.

Last year, Arizona had one of its coldest winters on record. Another factor of climate change is many of the extreme temperatures on both ends of the spectrum appear to be increasing, research has shown.

This means that much of last year’s snow melt didn’t melt as quickly and this essentially slowed down our monsoon season, Saffell said.

“We are hoping that the heat will really be a benefit,” Saffell said. “Here’s hoping for a monsoon and at least a few thunderstorms.”