PHOENIX — Hot weather is something we have come to expect across the Desert Southwest, especially during the summer months when triple-digit temperatures are the norm. But as our climate changes, those conditions we have come to expect are changing, too.
The Phoenix area is experiencing longer stretches of dangerous heat, more days of above-average temperatures, and more record-setting hot temperatures than cold ones.
It is a warming trend that is very familiar to Arizona’s State Climatologist, Nancy Selover.
Selover says that the daytime temperatures in Phoenix are now approximately 2.5-degrees warmer than they were from the 1940s to the 1970s. But Phoenix isn’t alone in experiencing this trend, “The kind of increase we’re seeing in Phoenix is the same kind of increase we’re seeing around the rest of the state” says Selover.
While a 2.5-degree temperature increase may not seem like a lot, Sean Sublette a meteorologist at Climate Central, explains that it can make a significant difference. “Think about that classic bell curve. A small increase in the average gives you a big increase in the extremes. In this case in extreme heat” says Sublette.
Data from 1970 to 2018 shows that Arizona is the third fastest-warming state in the country.
2020 also brought an end to the warmest decade on record for Phoenix, Flagstaff, Tucson, Yuma and Prescott.
Sublette says the science is clear on how we have gotten to this point.
“The basic physics has been known for more than 150 years. You add carbon dioxide to the atmosphere and that’s a warming, that’s a warming molecule once it is up into the atmosphere.” Sublette says. “We’re putting it in far, far more rapidly than it is going to be coming out and yeah, that’s from the burning of fossil fuels which is how we’ve been largely powering the economy.”
The global warming signal isn’t the only factor in our warming temperatures, though. Researchers at Arizona State University say future projections show the warming caused by urban development would be similar to that caused by greenhouse gases if development and emissions remain as they are now.
2020 gave us a glimpse of what this trend could mean for the future of our state. Selover says that years like the last will not necessarily become our new normal. “We have extreme variability and so I don’t anticipate anywhere near those records next year, or potentially the year after that,” says Selover.
However, according to Sublette, the threat of experiencing similar extreme heat more frequently is what is cause for concern. “Years like last year will become more common than they have been in the past,” says Sublette.
So, the question is will Phoenix one day become uninhabitable?
Selover says she doesn’t believe the Valley will become uninhabitable. Instead, she says we will find a way to deal with the heat.
Sublette says that Phoenix will not look like a scene from Mad Max in 50 years, however, he says we could see days where it is just too hot and dangerous to be outside for any length of time. He says we will likely see failures of our infrastructure before we get to that point.
Sublette says there is still time to slow the trend. “We need to find a way to stop putting in carbon dioxide into the atmosphere so that we don’t induce further warming 20, 30, 40 years hence, so unquestionably there are things we can do now.”
“From a climate standpoint we’re seeing an increase, yes it’s warming, there’s no question of that and we need to deal with it. We’ll try to change the trajectory in the future, but right now our best bet is we’re going to also have to adapt and mitigate it,” says Selover.
Both agree that combating and acclimating to climate change will require a multi-faceted approach, from reducing greenhouse gas emissions, to rethinking urban development and how our cities grow, and finding ways to cool ourselves without the need for more electricity.
“It’s manageable but we can’t just sit around waiting to be proactive in mitigating this problem,” says Sublette.
Otherwise, while the extreme heat may not make the Desert Southwest uninhabitable to all, it is our vulnerable populations who will suffer the most from the effects of climate change.
