When you think of Arizona, what usually comes to mind? For most of us, along with scenic desert landscapes, heat is probably at the top of the list. Very intense heat. In terms of average number of 90-plus degree days per year, we’re talking the home-of-the-two-hottest-cities-in-the-country-type heat.
So, that raises the question: how is an already exceptionally hot state faring in a rapidly warming planet? The answer, unsurprisingly, is not too well — at least relative to the rest of the country.
The bottom line is this: The climate crisis is making hot Arizona even hotter – and it’s impacting Arizonans in a variety of ways.
Today, millions of Arizonans are getting used to record-breaking heat. Just this decade, Phoenix has set new daily heat records on 33 different days, which is significantly more than any previous decade in recorded history.
It’s not just for highs, though. The city has set new records for hottest minimum daily temperatures 44 times as well — and that’s just since 2010.
As Paul Iñiguez, science and operations officer at the National Weather Service in Phoenix, explained to the Arizona Republic: “There’s no doubt climate change is happening. We see this reflected in the temperature records. It’s getting warmer. Our heat season is getting warmer.”
The thing is, escalating heat doesn’t just intensify drought and kindle wildfires — it poses a real threat to our health all by itself.
The sweltering temperatures Arizona sees today are nothing short of hazardous. Even for a relatively adaptation-capable country like the United States, they can be lethal.
In fact, heatwaves are the leading cause of extreme-weather event deaths in the country — even more so than hurricanes, fires, floods, or earthquakes. In the Phoenix area alone, 154, 179, and 181 people died from heat-related causes in 2016, 2017, and 2018 respectively.
This severe toll, which is partly due to a growing, particularly vulnerable homeless population, is also just a clear-as-day alarm on the threat rising temperatures present in Arizona.
Really, what’s happening in Phoenix echoes exactly what medical professionals already know: that children, the elderly, and the poor — just like Phoenix’s homeless population — are disproportionately vulnerable to these changes. Even temperatures significantly below Arizona’s rising highs have the potential to cause heatstroke and dehydration and can affect people’s cardiovascular, respiratory, and nervous systems.
What’s more, rising temperatures can increase the formation of ground-level ozone, a primary component of smog. This nasty pollutant has a variety of health effects, including aggravating lung diseases like asthma.
So, what might Arizona heat look like in a warming future?
For the state as a whole, “dangerous” heat days (days with a heat index above 105 degrees Fahrenheit) are projected to grow from 50 days a year to 80 on average by 2050 if emissions continue business as usual.
For cities, it’s even worse. Phoenix, which can get up to 21 degrees Fahrenheit (11.76 degrees Celsius) hotter than nearby rural areas because of the heat island effect, can expect its number of dangerous heat days to go from 80 to a stunning 147 by the end of the century.
WATER UNDER THREAT
As for many other regions of the planet, Arizona’s climate story is quickly becoming all about water.
The state, along with the rest of the Southwest, has seen its supply of this precious resource dwindle as rising temperatures have made droughts even more intense. The scale of drying seen is so great, in fact, that experts deem the entire region is undergoing a “mega-drought”.
As Columbia University professor Park Williams described of the Southwest in a recent Atlantic report, “The last 19 years have been equivalent to the worst 19 years of the worst mega-droughts on record.” As the article went on to explain, “only three recent mega-droughts — in the late 800s, the mid-1100s, and the late 1500s — were worse than the current period”.
Clearly, this drought, just like the heat seen across the region, is just not normal — and neither are its impacts.
Take the Colorado River, for example.
The flow of this critical source, which supplies over a third of Arizona’s water, has decreased by about 19 percent from 2000 to 2014 compared to its twentieth-century average. In the five years since, the river’s aridification has only continued. So, has climate change significantly contributed to its decline? Absolutely.
As experts Bradley Udall and Jonathan Overpeck explained in a 2017 study, “the emerging reality is that climate change is already depleting Colorado River water supplies at the upper end of the range suggested by previously published projections. Record setting temperatures are an important and underappreciated component of the flow reductions now being observed.”
This is likely just the beginning, however. As they go on to describe, “continued business-as-usual warming will drive temperature-induced declines in river flow, conservatively -20% by midcentury and -35% by end-century, with support for losses exceeding -30% at mid-century and -55% at end-century.”
Once again, the Colorado River supplies over a third of Arizona’s water supply, including 40 percent of the water for Phoenix — the fifth-most populated city in the United States. Though the situation may be under control today, Phoenix is among the fastest growing-cities in the country — a trend that’s expected to continue in coming decades. This is all happening just as scientists warn of worsening drought.
So, can Phoenix continue addressing this water decline exclusively through adaptation? A decline in basic resource availability won’t stop being a risk to residents until the real cause of the problem — our changing climate — is addressed.
THE ENVIRONMENT, WILDFIRES, AND AGRICULTURE
The sad reality is that such fast warming today is taking a serious toll on Arizona’s natural environment. The timescale at which our climate is changing is simply not giving much of the state’s vegetation or wildlife enough time to adapt.
This is worrying because once Arizona’s threatened varieties of flora are gone, they are likely gone for good.
Heat and drought are major culprits behind this decline, but also important are fires. From 1998 to 2018 alone, wildfires have burned over 1.5 million acres of Arizona forests.
Perhaps more revealing of climate’s impact, however, is that today the Western U.S. sees a whopping three times more wildfires burning per year than in the 1970s. Plus the 10 biggest fires in the state’s history have all happened just since 2002. What’s more, the wildfires destroying the environment can significantly reduce air quality throughout the state — posing an acute risk to people with respiratory and heart problems.
It’s not just the natural environment, though. Arizonan agriculture faces similar climate challenges.
Given that two-thirds of the water used in the state is used for farming, decreasing water supplies pose a clear and present danger to the sector. Similarly, rising temperatures are hurting many popular Arizona crops, including wheat, corn, cotton, mint, and alfalfa.
It’s also worth mentioning that agriculture in Arizona is an economic powerhouse, contributing $23 billion annually to the state’s economy and sustaining over 130,000 jobs. A threat to agriculture is a serious threat to the state’s overall wellbeing.
What’s more, Arizona is the nation’s second-largest producer of lettuce, broccoli, and cantaloupe in addition to the crops already mentioned. This means that consumers in the state and across the country will feel farmers’ pain too through increased prices and staple foods becoming less readily available.
Like the other impacts, wildfires and environmental and agricultural decline are only expected to get worse without bold action to slash emissions.
By 2050, Arizona is projected to see 115 at-risk days for high wildfire potential each year. Similarly, as one study predicts, major Arizona crops could decrease in yield by 12.2 percent for every degree Celsius of warming we let happen.
IT’S TIME FOR CLIMATE ACTION
These impacts are sending out a clear message: Arizona, just like the rest of the planet, is in the midst of a climate crisis that calls for urgent action.
There is good news, though. This state, much like the rest of the Southwest, has unprecedented potential to reap the growing benefits of clean, limitless solar energy. In fact, as a state with some of the best solar resources, hardly any place is as well equipped for the renewable energy rush we need as Arizona.
We have the solutions to the climate crisis – now, we just need to push them forward.
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