A checkerboard grass design offers walkability and a cooler surface temperature.
Courtesy Bowonpat Sakaew, iStockphoto
“It makes sense to grow more trees and have reflective surfaces that are light and white and can reflect all the radiant heat.”
— Barrak Alahmad
When hurricanes Matthew and Irma tore through Jacksonville, Florida, in 2016 and 2017, the city was left reeling. Streets filled with floodwater, entire neighborhoods sat in darkness for days and recovery stretched on long after the skies cleared. The back-to-back storms exposed just how vulnerable the city was to a changing climate.
“There was a growing realization of the need for resilience work following those hurricanes,” said Anne Coglianese, MPA, the city's chief resilience officer. “Flooding was obviously one of the big hazards we were looking at, but increasingly we also had to pay attention to heat. Depending on where you were in Jacksonville, you could experience a temperature differential of up to 12 degrees.”
City leaders responded by hiring Coglianese in 2021 and launching Resilient Jacksonville in 2023. The groundbreaking 50-year strategy provides a roadmap for ensuring that the city grows in ways that protect residents and businesses from the effects of climate change and preserves its natural resources. Moreover, the city was among 10 selected by the Smart Surfaces Coalition, a 40-plus-member nonprofit organization that brings together experts from key sectors to advise and help cities thrive despite climate threats, and received grant funding.
The coalition promotes citywide engineering solutions to cool entire communities, such as planting more trees, installing reflective roofs and replacing dark heat-absorbing sidewalks with lighter, more reflective materials.
“We didn't even know the full value this was going to provide when we applied for the grant,” said Coglianese, noting that the partnership has turned into one of Jacksonville's most innovative. The flexible model has allowed Jacksonville to tap into outside expertise whenever it is needed, whether on major policy work or small but critical design tweaks.
“Our budget is really tight, so our bandwidth is stretched really thin,” Coglianese told The Nation's Health. “Having this group of really smart people that are willing to jump in at any time and help out has been a godsend. It's a model I had never experienced before, and it's been game changing.”
Around the globe, climate change is intensifying extreme weather and driving more frequent and destructive heat waves, storms and floods. Experts say extreme heat is one of the most pressing public health threats tied to climate change, with impacts ranging from heart disease and heat stroke to workplace injuries and limiting learning for children in school classrooms.
Heat threatens human health
According to the Federation of American Scientists, heat kills more Americans every year than hurricanes, floods and tornadoes combined, and the number of heat-related illnesses is even higher.
A worker installs a vertical garden, which replaces exposed graphite, on a building in Sao Paulo, Brazil, in 2017. Research shows greenery reduces daytime and nighttime temperatures.
Photo by Alfribeiro, courtesy iStockphoto
“We're beyond just showing the adverse and bad impact of heat on our health, because that is established now,” said Barrak Alahmad, MD, PhD, MPH, a senior research scientist at Harvard T.H. Chan School of Public Health. “The focus is now shifted toward solutions.”
Dark materials such as asphalt, concrete and traditional rooftops trap the sun's energy during the day and radiate it back into the air at night, creating urban heat islands that can make cities as much as seven degrees hotter than surrounding areas, Alahmad told The Nation's Health.
“We call these dark surfaces ‘stupid' surfaces rather than ‘smart' surfaces,” he said. “They make our cities really hot, but it doesn't have to be like this. We have to present solutions. It makes sense to grow more trees and have reflective surfaces that are light and white and can reflect all the radiant heat.”
Modeling shows that even modest adoption of smarter options, such as replacing 20% of surfaces in a city, can lower urban temperatures by several degrees, which would translate into fewer emergency service calls, improved worker productivity and healthier, more livable neighborhoods.
Jacksonville's work with the Smart Surfaces Coalition serves as a model for how budget-challenged local governments can gain capacity to prepare for and mitigate the impacts of climate change. The coalition supports the city's resilience strategies, including integrating smart surface solutions into infrastructure and planning initiatives.
In addition to Jacksonville, other cities partnering with the coalition include Atlanta, Boston, Dallas, New Orleans, Phoenix and San Antonio, as well as Charlotte, North Carolina; Columbia, South Carolina; and Portland, Oregon. The program gives leaders immediate access to top-tier research, international experts, policy analysis and technological developments to inform their climate change mitigation strategies, which they say are crucial to understanding which strategies will be most beneficial.
With federal climate leadership weakening, states and cities are under pressure to fill the gap, said Grace Wickerson, MS, senior manager for climate and health at the Federation of American Scientists.
“States need to plan, invest and lead on extreme heat now because the problem is only getting worse,” Wickerson told The Nation's Health. “We're really excited about the opportunities at the state and local level to move heat policies forward. State and local governments hold the keys to codes, building standards and zoning. There's a lot of potential and available levers to pull.”
Green rooftops with light-colored surface, such as these in Hangzhou, China, can help keep buildings cooler and can improve health for indoor workers and city residents.
Photo by Dimitriosfos, courtesy iStockphoto
Aiming to cool neighborhoods and save lives and money, the Atlanta City Council in June passed a landmark smart-roof policy that is projected to cool the city by up to 6.3 degrees in some neighborhoods, prevent millions of tons of carbon emissions, reduce air pollution and generate nearly $800 million in net financial benefits.
“But more importantly, it will save lives,” Jimmie Smith Jr., MD, MPH, president of the Georgia Public Health Association, said in a statement. “Atlanta leaders are known for transformational actions, not reactions.”
The landmark ordinance amends the city's building code to add a new section to reduce heat produced by the city's dark and outdated heat-absorbing roofs, which place older adults, children and low-income communities at higher risk of illness and death from heat exposure.
The ordinance supports evidence-based science, is built around social determinants of health and addresses the environmental conditions that harm the most vulnerable.
In the Western U.S., Phoenix recently introduced “Shade Phoenix,” a tree and shade master plan that leverages heat-mapping tools and reflective or green surface interventions to cool neighborhoods and reduce public health risks in the nation's hottest metropolitan areas. Unanimously adopted by the Phoenix City Council in November 2024, the plan aims to create a future where all community members and visitors benefit from trees and built shade.
Recognizing shade as a critical community resource, the plan prioritizes areas in Phoenix where people are outdoors the most and where populations are most vulnerable to extreme heat, said David Hondula, PhD, MS, the city's director of heat response and mitigation.
“Shade is crucial for determining how safe and comfortable people feel in outdoor spaces, reducing the net heat load on the human body by more than 30 degrees,” Hondula told The Nation's Health.
Shade also benefits physical infrastructure by increasing lifespan of materials that degrade under sun exposure, making it easier to keep homes, vehicles and indoor workspaces safe and comfortable, Hondula said.
The plan calls for dozens of actions over the next five years, including planting more than 27,000 new trees and building hundreds of new shade structures at local schools.
Plants adorn the front of a building in the Hague, the Netherlands. Greenery and light-colored surfaces can reduce heat.
Photo by AerialPerspective Works, courtesy iStockphoto
Back in Jacksonville, Matt Fall, MPA, the city's senior bicycle-pedestrian coordinator, has been working with coalition experts to weave smart surfaces into nearly every major mobility and infrastructure initiative. That includes a forthcoming Green and Complete Streets ordinance requiring developers to integrate bike- and pedestrian-safe designs with green infrastructure.
It also extends to Jacksonville's first-ever Vision Zero Action Plan, aimed at enhancing pedestrian and cyclist safety and eliminating traffic fatalities. Jacksonville is among the most dangerous U.S. cities for walking and biking, ranking third for cyclist deaths and 15th for pedestrian injuries from impacts.
Permeable pavers do not just soak up stormwater — they make intersections safer by being less slippery for walkers and cyclists, Fall said. Moreover, reflective pavements and shade structures keep cyclists and pedestrians less vulnerable to heat-related health risks.
The city's integrated approach is one of the first of its kind in the country.
“Implementing smart surfaces into our Vision Zero Action Plan dovetails into safety and resilience,” Fall told The Nation's Health. “We had to do a virtual high five with the coalition on that one.”
For more information, visit www.smartsurfacescoalition.org.
- Copyright The Nation’s Health, American Public Health Association
