Global warming has changed city life in Phoenix: When it gets too hot, construction crews start work at 4 a.m. and the zoo opens at dawn. But for some people, the heat is more than an inconvenience. It can turn deadly.
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Phoenix, Arizona, is known for its proximity to the Grand Canyon, its cactuses — and its palm trees?
You wouldn't expect to see the tropical trees in the middle of a desert, and yet, there they are, gently swaying in the breeze on the side of the road welcoming visitors driving into town from the airport. They make for quite a sight in the dry, rocky landscape, where the dominant colors are red, brown and yellow. Palm trees, of course, aren't native to the Sonoran desert around Phoenix, and not everyone is a fan.
"Palm trees were just put here for the tourists," Patricia Solis, a geographer at Arizona State University (ASU), tells DW. "They are such a waste of a tree — they hardly provide any shade!"
Shade is a precious resource in Phoenix. The city consistently ranks among the hottest in the United States. The fall season should be setting in, yet stepping outside feels like getting into a car that has been parked in the sun for too long.
In the heat of a Phoenix summer, temperatures can rise up to 120 degrees Fahrenheit (almost 49 degrees Celsius). In 2018, the city saw 128 days with temperatures at or above 100 degrees Fahrenheit (38 degrees Celsius).
These high temperatures are the reason Phoenix is at the forefront of extreme heat research, a field that has garnered more attention in recent years. With rising temperatures due to climate change, officials from across the world are looking to places like Phoenix for advice on how to keep their cities livable and protect their citizens from heat-related illnesses.
Architectural ideas against the heat
Global temperatures are soaring, with climate change leading to hotter summers each year. But can design and architecture help people escape the heat and combat the causes of global warming?
Image: picture alliance/DUMONT Bildarchiv
Air-conditioning is the problem, not the solution
Nothing feels nicer than walking into an air-conditioned room after spending hours in the heat. But the International Energy Agency (IEA) identified the use of A/C as one the key drivers of the growth of electricity demand, accounting for 10% of all global electricity consumption. And all that electricity that needs to be produced somehow — which often involves the burning of fossil fuels.
Image: picture-alliance
Tel Aviv's 'Geddes Plan'
Long before the establishment of Israel in 1948, Scottish urban planner Patrick Geddes consulted the Zionist Commission in 1925 on how the future metropolis of Tel Aviv should be designed to minimize the effects of the desert heat. Its roads were to be built on a grid to channel the sea breeze from the Mediterranean into the city. To this day, the city center hugely benefits from this design.
Image: JACK GUEZ/AFP/Getty Images
Bauhaus: German design is cool, literally
Buildings in Tel Aviv also benefited from the Bauhaus school of architecture and design, which puts an equal emphasis on pragmatism as it does on aesthetics. The Bauhaus penchant for flat roofs, for example, has proven to be useful as they reflect solar heat. With new technology such as the advent of solar panels emerging over time, flat roofs have continued to be popular in hot urban centers.
Image: DW/I. Rottscheidt
Nigeria's chill design
The influence of Bauhaus can be seen elsewhere as well. Israeli architect Arieh Sharon built Obafemi Awolowo University in Nigeria in the 1960s using Bauhaus ideas that have since become the staple of smart design. He addressed the tropical climate by creating space for open gardens and courtyards for the wind to move. Classrooms are always 7 degrees Celsius cooler than the outside temperature.
Image: Keren Kuenberg
Forward thinking: Barcelona
If courtyards provide cooler air, cities like Paris and Barcelona know the way forward. With their city blocks planned around giant courtyards, residents not only benefit from a cooler microclimate but also from living in pleasant surroundings. More recently, the city started changing the way it channels traffic around the more than 500 city blocks in a bid to reduce carbon emissions.
Residents of lower-lying coastal regions have known for a long time that building elevated houses — so-called stilt houses — provides protection against flooding, which is a growing side-effect of global warming. The setup also cools the buildings from underneath. Granted, it is difficult to retrofit existing structures this way, but if you're in the market for coastal property, think stilts!
Image: Reuters/S. Nesius
Building climate-resilient cities
The growing number of so-called natural disasters is directly linked to climate change. When Hurricane Harvey hit Houston in 2017, the city benefited from the intelligent design of its 64-hectare Buffalo Bayou Park, which served as a flood plain bearing the brunt of the flooding. The park itself remained largely unscathed.
Image: Photo by Jim Olive, courtesy of Buffalo Bayou Partnership
Combating climate change and heat in the Middle East
Nowadays, there are cities springing up overnight in the Middle East, providing fresh opportunities to address the effects of climate change from the get-go. Next to Abu Dhabi's airport, there is an entire suburban city being built, designed to be run on renewable energy and have net-zero emissions. Masdar City might be a utopia today but could deliver the blueprints for tomorrow's urban designs.
Image: Masdar
Ancient design from Oman
The street temperature in Abu Dhabi's Masdar City neighborhood is up to 20 degrees Celsius cooler than the heat in the surrounding desert, as a wind tower channels cooler air from the sky and pushes it down to form a cooling breeze. This idea, however, is copied from the ancient city of Muscat, Oman, where taller buildings were designed to channel winds into narrow streets in a similar manner.
Image: picture alliance/DUMONT Bildarchiv
Fixer upper?
While old buildings are charming, they are often built in a way that maximizes the effects of high temperatures, inadvertently contributing to global warming. Some countries like the UK are pushing to retrofit these dwellings with improved insulation in a bid to cut their greenhouse gas emissions by 80%. Such building projects can be costly, with a "deep retrofit" coming at a price tag of €20,000.
Image: Imago/Future Image
Concrete: Hello or goodbye?
To address the climate needs of the future, people have to embrace new building materials. Above all, there's a call to stop the widespread use of concrete with its large carbon footprint. But existing concrete buildings, especially the giant Brutalist structures from the 1960s, are also great heat insulators. So in short: Stop using concrete but make the most use of existing concrete structures.
Image: DW/K. Langer
The future is actively passive
If you're building a house in the near future, think passive. Passive design incorporates features that minimize your impact on the environment. Think smaller windows, overhang roofs, space for solar panels or rooftop gardens, where the rain cools off your building while feeding plants that offset your carbon emissions. And they look great, too.
Image: Sam Oberter Photography
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Dying of heat
In Maricopa County, where Phoenix is located, extreme heat caused or contributed to 182 deaths in 2018. Of those fatalities, 30 to 40% happened indoors, in the victim's own home.
"In many cases of indoor heat deaths, they actually did have air conditioning in their homes," says Liza Kurtz, a researcher who works with Solis at the ASU School of Geographical Sciences and Urban Planning. "But they either had their electricity shut off because they didn't pay their bill, or the AC broke and they couldn't afford to fix it, or they didn't dare turn it on because it was too expensive."
For mobile home residents, the risk of indoor heat death is especially high. Melissa Guardaro, a research fellow with the Urban Resilience to Extremes Sustainability Research Network and a PhD student at ASU, has found that temperatures are even higher in trailer parks than elsewhere in the city. Mobile homes are mostly constructed of aluminum or vinyl plastic, materials that heat up quickly and easily reflect heat into the surrounding air.
"If it's 105 degrees downtown, it can easily be 110 or 115 degrees in a mobile home park," says Guardaro.
Is climate change making us ill?
02:25
On this Tuesday, heat is radiating from the trailers in a mobile home park on the outskirts of Phoenix, surrounded by desert, mountains and highways. Solis and Kurtz are conducting a study that is trying to figure out the effect of extreme heat on the physical and financial health of mobile home dwellers, and are here to speak with some of the residents.
One elderly woman is keeping her small, carpeted trailer at a relatively cool 78 degrees Fahrenheit (25.5 degrees Celsius) with the help of air-conditioning. But that comfortable temperature comes at a cost: she relies on microwaveable TV dinners — cooking with the stove or oven would eat up too much power — and she only does her laundry when she has no more clean clothes to wear.
Pouring concrete at 4 a.m.
One way Phoenicians are adapting to high temperatures is by adjusting their daily rhythm to avoid the hottest hours of the day. From June until August, the Phoenix Zoo opens at 6 a.m. and closes at 2 p.m.. And outdoor workers like landscape gardeners and construction crews arrive on the job before the crack of dawn.
Jerod Teller is a division superintendent with the Haydon Building Corporation and in charge of public construction projects. Today's job: pouring concrete for sidewalks and curbs in a parking lot in Avondale, a suburb of Phoenix. The crew's start time: 4 a.m..
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As superintendent, Teller had to arrive even earlier, at 3:30 a.m.. The sun hasn't risen yet and tall floodlights stand out against the pitch-black sky, illuminating the construction site. Despite the gloom, the temperature is already a stifling 86 degrees Fahrenheit.
While getting up in the middle of the night is just part of the job for Haydon's construction workers in the summer, their families lose out. Andrew Perryman, a project superintendent, has a 14-month-old baby at home whom he hardly gets to spend time with because of the night shifts. He said his wife isn't too happy with the situation, but she understands that working in the daytime heat isn't an option.
Teller admits his spouse isn't a fan of the early start time, either. "When my alarm went off at 2 a.m. this morning, my wife just turned to me and asked 'Why?'," he says with a laugh.
'Two seasons: Heaven and hell'
But despite the early hour, none of the men seem tired. When the long hose connected to the concrete truck starts spitting out the gray mass, they immediately begin their routine. One worker moves around the nozzle to distribute the concrete evenly across the area that will become a sidewalk. Several others follow with shovels and a long bar to flatten out the material. The way the bright stadium lights illuminate the men in front of the black night sky make them look like high school football players getting ready for a Friday night game.
When the sun comes up around 6:15 a.m., temperatures immediately began to rise. Teller says his company regularly reminds its workers to stay hydrated, and each worker is given a card detailing symptoms of heat exhaustion.
"There are just two seasons in Phoenix," says Perryman, referring to summer and the rest of the year. "Heaven and hell."
The crew pours concrete until around 7 a.m., finishing just before it starts to get too hot. After that, some men finish off the brand-new piece of sidewalk, while others set up for the next day — another early morning in Phoenix, Arizona.
How cities and people can beat the heat
Heat waves are becoming more common and scientists predict that they'll only become hotter and longer-lasting in the future. So how can cities and their residents stay cool when the mercury rises? DW takes a look.
Image: picture-alliance/dpa/P. Pleul
Paint the town white
One easy way to combat the harsh summer sun could be painting your roof white — an idea long embraced by Greeks. A black roof absorbs most of the sunlight that hits it, heating up the underlying home like an oven. Light-colored surfaces, on the other hand, can reflect up to 80 percent of the sun's rays, keeping inside temperatures cooler. That also means a lower carbon footprint and energy bill.
Image: picture-alliance/robertharding/M. Simoni
Water in the city
Bodies of water like lakes, canals and rivers can help bring down the temperature in cities, cooling the surrounding air when it evaporates. Water doesn't adjust to temperature changes quickly and so, to an extent, can maintain a certain level of heat or coldness. Urban areas short on space don't need to have a huge lake to benefit from this cooling effect — fountains can also help.
Image: picture-alliance/dpa/W. Grubitzsch
Add a little green
Planting trees is a simple way to create cool spaces in cities. Specifically, it's the shade they provide and the water they evaporate through their leaves that make the real difference. If planted strategically along streets or around buildings, they can significantly cool inside temperatures and combat the urban heat island effect.
According to a study by the Technical University of Munich, several small parks can better cool a city than one big one. That's because large parks lower temperatures in one specific place, while small parks, if evenly spread out, can impact a much wider area. Connecting city green spaces with wind corridors can also help air flow and to reduce heat.
If you don't want to paint your roof white, green roofs, or rooftop gardens, can also have a cooling impact on urban areas. The vegetation absorbs heat through the evaporation of rain water, while at the same time insulating the building and reducing the need for air conditioning. Rooftops also make a great place to plant vegetables, from pumpkins (above) to carrots.
Image: Getty Images/AFP/P. Lopez
Spice spice baby
While you're building your rooftop garden, you also might want to consider planting some chili. That's because spicy food, believe it or not, can keep you cool. It forces you to sweat, lowering your body temperature.
Image: picture-alliance/AP Images/D. Epperly
Sweating through the heat
When temperatures rise above 30 degrees, it might seem sensible to eat ice cream or drink something cold. That's not what the experts advise, though. Just like spicy food, drinking hot tea will increase your body temperature and cause you to sweat, which in turn cools your body down.