On a typical July day in Abu Dhabi, the temperature soars well over 100 degrees. But a recently built park is designed to make it possible to stay comfortable outside. A canopy with roller shades can be closed during the day, and opened at night to allow heat to escape. Benches are partly shaded by nearby buildings, with another canopy structure overhead for extra shade. Carefully placed walls help channel a breeze through the park and block heat from traffic. Strategically placed misting devices spray water in the air. Native plants offer evaporation—and a psychological perception of coolness.
The park, part of the Abu Dhabi Climate Resilience Initiative, is one example of the type of design that could help cities around the world—like Seattle, which reached a record high of 108 degrees in June—deal with extreme heat. The Middle East is “probably a decade or so ahead in thinking about sustainability, because they have to be, on issues of heat and comfort,” says Kishore Varanasi, principal and director of urban design at the architecture firm CBT, which designed the park and other pilot projects to mitigate heat in Abu Dhabi, and is now bringing some of the same approaches to cities like Boston. “They know the problem, and they’re trying to get ahead of it.”
In the center of Abu Dhabi, the city is testing new, heat-mitigating designs in different settings—a high-density neighborhood where tall buildings already provide some shade, a lower-density neighborhood, and an intersection where people have to cross the street. In each case, the intervention is tailored to the neighborhood. “Each microclimate at a location is very important to understand,” he says. Existing buildings may provide shade at certain times of day and either block or help the flow of wind. There may be trees and green space, or sprawling pavement that reflects heat. Building materials and air conditioners may also push more heat onto the street. Passing cars add more heat.
Many cities are adding trees to help fight extreme heat, since trees both offer shade and release cooling water vapor through their leaves. It’s especially important in low-income neighborhoods that have fewer trees now. But in built-up neighborhoods that can’t easily add green space—or in drought-prone cities where it’s harder to keep trees alive—there are other strategies that can work together to help make hot days more comfortable. The pocket park is one example. Some of the features draw on older ideas, such as a design called “sikka,” a traditional Middle Eastern pathway between buildings that’s oriented with the wind to maximize the breeze. At the intersection designed for the pilot project, cantilevered shade structures and shaded seating make it more comfortable to wait at a bus stop or wait for the light to change at a crosswalk.
In new developments, better resilience to heat can be built in from the beginning. In Masdar City, a long-delayed sustainable community under construction in the desert outside Abu Dhabi, everything about the design considers heat. “We’re building a city from scratch,” Varanasi says. “So when you do that, obviously, you have the greatest control over every element.” The placement of buildings considers how to keep the sun out, shade public spaces, and take advantage of prevailing winds, and green spaces are planned throughout the city.
In the U.S., where most cities face a rapid rise in the number of extreme heat days each year, similar strategies could help. It’s important to consider the full system, Varanasi says—an approach like painting streets white could make roads cooler but end up reflecting more heat onto pedestrians and buildings nearby. More sweeping changes could also help, such as shifting to neighborhoods that prioritize walking and biking over driving. If parking spaces become green space, for example, a neighborhood will be cooler because less heat is radiating off pavement. Designs can also serve a dual purpose of helping in both summer and winter; in the Boston area, for example, a proposed roof-like structure over a pedestrian pathway could shade the area in hot weather and hold back snow and rain when it’s cold.
American cities are now being forced to think more about these types of solutions. Until recently, heat “has been an invisible threat, compared to sea level rise,” he says. “People could really understand sea level rise, but they haven’t focused on urban heat as much. But it’s becoming increasingly clear now that it is an issue in the States.”