Why Public Space Is a Critical Tool for Climate Resilience
After record-breaking summer heat, 4 experts share strategies to keep cities safe, equitable and cool
June 2023 was the hottest June on record. Then came July. It was not only the hottest July ever, but the hottest month ever recorded. Along with floods, fires and warming oceans, this has been a summer of a planet sending off alarm bells.
“Climate change is here,” U.N. Secretary-general António Guterres told reporters. “It is terrifying. And it is just the beginning. The era of global boiling has arrived.”
As people around the world consider how to keep themselves and their communities safe in the face of fires, floods and temperatures that continue to rise, many solutions lie in our shared public spaces — especially when considering that one-third of urban land across the globe is public, and when thinking beyond the physical design of space to how these places are managed and programmed. From parks and libraries to community centers and sidewalks, there are lots of opportunities for cities to reassess the role their public spaces can play.
We reached out to four thought leaders (Kofi Boone, Sandra Calhoun, Jad Daley and Ryan Mooney-Bullock) to ask for their ideas about the role public spaces can play in mitigating climate change. They shared a wide range of practical and strategic ideas — and provided insights cities can apply to help people and neighborhoods stay safe, equitable and cool in our warming world.
“There are significant disparities”
Our experts shared a wide range of solutions communities can use to mitigate climate change through the lens of public spaces. But they agreed on a key problem facing America’s cities: neither the impacts of climate change nor access to cool spaces is distributed equitably.
“As inequities in the risks of flooding and the increasing violence and frequency of storms become more apparent, most people still don’t know that heat exposure is the leading cause of death due to the effects of climate change,” said Kofi Boone, professor of landscape architecture and environmental planning at North Carolina State University. “There are significant disparities based on age, class and race that exclude many people from accessing cooling on our hottest days.”
Public space is essential to responding to climate impacts in ways that support greater equity. “Investment in cooling, including establishing healthy tree canopies, better access to shaded public spaces, and even deploying pop-up cooling stations in underserved areas, can make great impacts on this pressing challenge,” Boone said. Boone pointed to the American Society of Landscape Architects and the organization’s Climate Action Plan, as well as the Landscape Architecture Foundation’s Landscape Performance Series, as valuable resources for communities looking to prioritize equity and climate mitigation.
Jad Daley, president and CEO of American Forests, pointed to the importance of tree equity in cooling the nation’s cities, especially in neighborhoods most impacted by climate change. American Forests’ Tree Equity Score shows that the lowest-income neighborhoods in the US have on average 26% less tree cover and are 6 degrees Fahrenheit hotter compared with the highest-income neighborhoods, and neighborhoods with the most residents of color have 38% less tree cover and are 13 degrees hotter, compared with communities with the fewest residents of color.
“Trees are a magical device to protect our cities from climate change,” Daley said. “They cool the air while scrubbing smog and carbon dioxide alike. But these critical benefits are not reaching everyone.”
Daley said Phoenix, Arizona, provides “a perfect example of a strategic and functional approach” to achieving tree equity. The city made a first-in-the-nation commitment to achieving tree equity in every neighborhood by 2030. That means “placing trees within priority neighborhoods where they will most directly benefit people,” Daley said, including 100 carefully selected “Cool Corridors” where trees will provide shade for people walking, biking and waiting at public transit stops. In some cases, the tree plantings are paired with reflective pavement to further reduce heat. Other cities, including Dallas, are also prioritizing adding trees along walking paths to schools. And Philadelphia recently released a plan to get each neighborhood to 30% tree cover within 30 years, helping reduce temperature differences between Philly neighborhoods that currently reach up to 22 degrees on hot summer days.
Planting — and sustaining — urban tree canopies
All of our experts mentioned planting and caring for trees in public spaces as a powerful way to shade and cool cities while protecting people from rising temperatures. Ryan Mooney-Bullock, executive director of Green Umbrella, a regional sustainability alliance based in Cincinnati, Ohio, emphasized the importance of considering which types of trees communities should plant. “Plant large numbers of native, high-shade trees, preferably ones that will tolerate warmer climates as our planting zones shift,” she said.
Location matters, too. To ensure the “life-saving and quality-of-life benefits of trees can reach the most people,” Daley recommended planting and caring for trees in public spaces such as streets, transit stops, parks and community spaces, especially in neighborhoods where trees are systemically lacking.
Walking and biking trails are another critical location. “In the summer, the difference between a shaded walk-bike trail and one that is not shaded is massive,” Daley said. “Many people can’t or won’t use these trails if they are too hot. In some cases, using an unshaded trail would put people at unreasonable risk.”
With fewer people using trails, the impacts include less exercise, less social activity and more greenhouse gas emissions as people take more trips by car. “Creating green and resilient pathways through our communities ties to so many different aspects of community health and resilience, and our efforts to slow climate change down,” Daley said.
But planting trees alone won’t solve the challenge of urban heat islands. Cities must also have a plan for caring for these publicly managed trees over the long haul. Boone emphasized the importance of maintaining existing tree canopies — an investment that cities often overlook, resulting in trees that never deliver their full benefits because they never reach maturity. “Preserving and maintaining existing urban forests not only helps us cope with heat, but also supports increased biodiversity and climate adaptation,” Boone said. Caring for a city’s existing trees — as well as its newly planted trees — will be increasingly important as extreme weather becomes more commonplace, with everything from heat waves to drought to large storms and flooding negatively impacting trees.
Public spaces for cooling people
Beyond mitigating rising temperatures, public spaces have many roles to play in providing respite from the heat. And that often means investing in programming, management — and access to cool spaces in the summer.
“Programming and management are key factors to consider,” said Mooney-Bullock. “In Cincinnati, where I live, we have many public pools with very limited hours, or that do not open in a given summer at all, because of staffing or funding shortages.” She said public and private investment in these community resources is a matter of health and safety during times of extreme heat — and she provided a range of ideas for communities looking to use their public spaces to provide a cool haven. “Public spaces with air conditioning could open as cooling centers. Outdoor gathering spaces can install misting systems to help people cool off. Public pools and splash pads could extend hours of operation or eliminate admission costs.”
Sandra Calhoun, director of the sanitation and environment program at Philadelphia’s Centennial Parkside CDC, agreed that cooling people is important, saying “The design and programming focus should be on nature, greening and waterscapes that provide for serenity and livability.”
She also shared an example of water play that inspired her, pointing to Dilworth Park, located in the plaza of her hometown Philadelphia’s City Hall. “The waterscape is full of children with their bathing suits on playing and running through the shoots of water,” Calhoun said. “Quite cool and refreshing!”
Investing in sustainable infrastructure
As communities design the public spaces of the future and update the public spaces they already have, our experts recommend doing so with an eye toward sustainability.
“Today’s public space design should reflect climate resilience features that are best suited for communities, visitors and inclusion for people of all abilities,” Calhoun said.
Boone emphasized the importance of sustainable standards for new development. “Policies that challenge new development to reduce paved surfaces and hardscape rooftops, as well as rewarding increased vegetation and tree planting, can foster systemic changes,” he said. “Consider renewable energy infrastructure in new public spaces that can power cooling without emitting carbon and compromising the power grid.”
He pointed to Miami-Dade County, which not long ago appointed the world’s first urban heat officer, Jane Gilbert, as a source of inspiration for sustainable infrastructure and many other climate resilience points. “Miami is investing in a position, policies and resources that center underserved communities and focus on urban heat in a comprehensive way,” Boone said. “They are aggressively boosting their tree canopy and working on campaigns to persuade more people to walk and bike. And they are working with people as ‘citizen scientists’ to help install and monitor heat sensor equipment to measure progress on their cooling goals.”
Mooney-Bullock recommended a range of specific design features, including replacing dark-colored roofs with green roofs, increasing the amount of reflective pavement and replacing pavement with natural materials — “especially those that create shade.”
“All of these strategies decrease the amount of heat that is stored in our built environment and decrease the urban heat island effect,” she added.
For inspiration on climate resilience, Mooney-Bullock looked to the Waterplein Benthemplein, or “Water Square,” in Rotterdam, the Netherlands — a public square that also helps the city manage stormwater and prevent flooding from intense rainfall, a climate change-related challenge Rotterdam is grappling with. “They took an underutilized public space between buildings in their urban core and turned it into a multi-use public space that also captures high-intensity rainfall,” Mooney-Bullock said. “With features designed for public performances, athletics, skateboarding and dance, it turns rainwater collection into a public amenity both in dry and wet periods.”
To support communities in affording these and other investments, Calhoun recommended that communities invest in climate finance tools, such as green bonds, climate budgeting and citywide carbon pricing. “This money would be spent directly on a wide range of activities to slow down climate change, which would help the world to reach a target of limiting global warming,” she said.
With climate change upon us, innovation and adaptation are essential, and our experts emphasized that every city needs to be considering the public realm as part of the solution to mitigating impacts from rising temperatures to harmful air quality to the inequities facing our communities. Cities should lean into the public realm to deliver a wide range of climate-related benefits — cooling people, collecting stormwater, providing safe and active transportation, cleaning the air — all while cultivating more joyful communities.
Reimagining the Civic Commons is a collaboration of The JPB Foundation, the John S. and James L. Knight Foundation, The Kresge Foundation, William Penn Foundation, and local partners.
