It’s no secret that the desert is hot, but in the last few years the heat in Phoenix has been breaking new records. According to Arizona State climatologist and Senior Global Futures Scientist with the Julie Ann Wrigley Global Futures Laboratory Dr. Erinanne Saffell, “Phoenix has had hot temperatures dating back to the 1900s. However, in 2020, for the first time, Phoenix experienced 50 days of temperatures of 110 degrees or higher.”
The trend continued in 2023 when temperatures stayed at 110 degrees for 55 days. “This change is showing that those days of 110 degrees and higher are increasing and will continue to increase,” Dr. Saffell says.
The temperature increases are not helped by the fluctuations in precipitation across various regions of the state, and high nighttime temperatures.
“The nighttime temperature is also increasing which is a big issue for researchers,” Dr. Saffell says, “and that is because of the urban heat island.” This effect basically occurs when urbanization causes various buildings and surfaces to hold on to sunlight.
“Researchers are looking into ways to keep that sunlight from being stored in those materials,” according to Dr. Saffell. One possible solution is to consider changing the color of the surfaces as a way to block the sunlight from entering.
Another option is to reduce the urban heat island effect is planting trees. Dr. Saffell says that “in addition to blocking sunlight, trees can put water into the atmosphere — a process called transpiration.”
Urban planners may also look at building designs in order to reduce how sunlight is held between and in buildings. Dr. Saffell’s office is in one of the buildings at Arizona State University that was designed to block the way the sunlight comes in. Other buildings in and around Phoenix have canopies built over the windows to reduce the heat load.
The ultimate priority is to keep people safe from the heat. Extreme hot weather is typically the killer of more people than any other weather phenomena in the United States. To reduce heat-related deaths, the governor of Arizona has implemented a heat plan. Dr. Saffell says this is a proactive way of keeping people safe by managing and providing important resources to people.
To mitigate the impact of the extreme heat, Saffell believes that it is also good for people to know what is happening in their backyards. “Individuals can measure the surface temperatures with an outdoor thermometer in their backyard, and look for ways to keep their house cooler,” she says. Saffell adds that planting certain vegetation in their backyards also helps put water in the atmosphere.
“Every little bit helps to lower the heat.”