“Boston needs to ramp up its heat adaptation strategies, because two summers ago, the city had 40 days of temperatures over 90 degrees. This was a major problem because no one in the city has air conditioning,” said landscape architect Diana Fernandez-Bibeau, ASLA, deputy chief of urban design at the Boston Planning and Development Agency, during the Living Future conference in Washington, D.C.

Fernandez-Bibeau and Tamar Warburg, director of sustainability at Sasaki, outlined Boston’s innovative new plan for addressing extreme heat, which is part of its Climate Ready Boston effort. The plan promotes strategies ranging from parks to street trees, green roofs to library cooling centers, and offers “multiple layers of benefits.”

“The city is centering people in the resilience process. We’ve completed [sea level rise and flooding] planning for all the city’s coasts. And now with the heat plan, we are ahead of the ball,” Fernandez-Bibeau said.

Heat is a priority for the city because it is “the number-one cause of weather related deaths,” she said. “Children and older adults are at risk, along with those with pre-existing conditions like asthma and diabetes. Construction workers, athletes, the unhoused, and those without air conditioning are also at risk.”

Through the 350 plus-page plan, the city argues that heat depends on how someone experiences it, rather than the actual temperature. “Age matters, as does someone’s adaptive capacity, which relates to level of access to cooling. In built-up environments with no trees, parks, or splash pads, perceived heat can have a greater intensity.”

Fernandez Bibeau emphasized that the data used in Boston’s plan is rooted in perceived heat, which she called “revolutionary.” The city decided not to use federal data, instead creating new climate datasets and modeling that they argue tell a truer picture of what heat feels like on the ground in different conditions.

The city brought together a multidisciplinary team, which was led by Sasaki, a landscape and planning firm, and includes All Aces, a diversity, equity, and inclusion consultancy; Klimaat, which provided heat data, modeling, and visualizations; and WSP, which examined how to finance heat solutions.

Equity was a major focus for the team. Boston has a dark racial past, and “many areas of the city were redlined and subject to disinvesment by the Boston city government,” said Warburg. When the Sasaki team identified the hottest areas of the cities, they found they almost perfectly lined up with the communities that had been subject to racist policies in the past.

The city focused on these previously redlined areas, what they call “environmental justice communities” — Chinatown, Dorchester, East Boston, Mattapan, and Roxbury.

According to Fernandez-Bibeau, these are not what have been described as vulnerable communities. “There are vulnerable conditions and infrastructure, not vulnerable communities. These communities are actually incredibly resilient, but their environment doesn’t serve them.”

In the five neighborhoods, temperatures can be up to 7.5 degrees hotter, which means the difference between 83 and 90 degrees. And the communities are even hotter at night. “They have 70 percent less parks and open space and 30 percent fewer street trees than communities that weren’t redlined,” Warburg said.

Chinatown was found to be Boston’s hottest neighborhood. “89 percent of it is impervious, and there is little greenery or shade.” The community is a heat island, which is caused by paved streetscapes and the thermal masses of buildings. “Those buildings radiate heat at night, reducing the ability of the community to cool down.”

To kick-start the work in the neighborhoods, the city and the planning team set up advisory boards, hosted open houses, sent out surveys, and hosted youth charrettes.

Sasaki also asked Bostonians to mark on a map where they felt hot. “In the comments, recurring themes came up — the lack of shade and trees, the impacts of pollution, and affordability issues,” Warburg explained. And the comments also outlined where Bostonians go for cooling relief.

City residents could use a website to create their own three-panel comic strip, choosing colors to indicate how uncomfortable they are. “It was qualitatively helpful.”

And with each neighorhood, the team also drew possible solutions on top of a transect, showing how trees, parks, shade structures, and green roofs could be woven in.

Sasaki and Klimaat tested the cooling benefits of a range of strategies, including converting streets to parks, planting street trees and tree groves, and adding shade structures. They also examined the different cooling benefits of green roofs; cool roofs, which are painted white; and shaded green roofs.

The team looked at how to make transportation systems more heat-resilient, too. Through pocket parks and cool streets, walking to the bus or subway will be made a cooler experience. So will “cool bus stops” with shade canopies. All these strategies together form an implementation toolkit.

The plan also covers how to increase equitable access to cooling. In the past, the city had opened up cooling centers but asked for personal information, such as name, phone number, and health insurance information.

Warburg said the unintended effect was to drive away many prospective visitors. “This was asking too much info,” particularly for the unhoused; immigrants, who may not have documentation; and others concerned with their privacy. Warburg learned that many instead “went to public libraries, which have water, bathrooms, wi-fi, and a place to sit.”

As a result of the research, the city will “move away from asking for IDs” at the cooling centers in the future, Fernandez-Bibeau said.

The city government and Sasaki piloted the creation of new outdoor cooling areas at a few public libraries, which provided free wi-fi, shade, and misters. “At the East Boston public library, the plan was to keep up the temporary outdoor cooling pop-up for a few weeks; it ended up staying for four months,” Warburg said. (see image at top).

To increase resilience, the plan calls for operationalizing heat management, including heat risk notifications through the city’s 311 system.

Other priorities include: mobilizing city government workers with heat wave resources; and targeting utility assistance programs and long-term home energy retrofits towards at-risk community members.

Building community capacity to manage heat solutions is another focus area. “Neighborhood champions can help ensure older residents are using fans and drawing their shades,” Warburg said.

“Heat resilience is layered. All solutions are needed to mobilize communities,” Fernandez-Bibeau said.

Now the hard part. Implementation challenges will need to be addressed, such as securing the capital budgets to develop new cooling nature-based solutions and the maintenance budgets to support that work.

And some underserved communities are already concerned that adding trees will have a gentrifying impact. “What if by adding trees we make it less affordable to live here?” Warburg worried.

Tree maintenance issues are a factor. Cities like Philadelphia and Boston have planted thousands of trees but seen many of them die because neighbors didn’t have the time or resources to take care of them.

“During drought and heat waves, trees need extra care; without that, it impacts their ability to thrive,” Fernandez-Bibeau said. The city now has four arborists on staff who can help watch over the canopy.

And to ensure future development doesn’t cause more heating, projects not only need to include energy and carbon modeling, but also thermal comfort modeling as a matter of course. “Any development’s impact should be understood relative to existing heat conditions.”

Fernandez-Bibeau said more planning will be needed to advance the heat plan as well. “Heat adaptation will require studies involving the city’s urban forest plan, open space and recreation plans.”

“Boston faces some extreme challenges. Inequities and climate climate are interconnected,” Fernandez-Bibeau said. And to date, the city has been “hindered by old systems and structures, which are not enabling communities to grow in an equitable way.”

Boston Mayor Michelle Wu has formally called for the city to abolish its planning and development agency and create a new planning and design department. But building capacity to implement the changes needed will take time.

While the heat solutions are rolled out over the coming years, Fernandez-Bibeau urged policymakers and landscape architects to use projected weather data for 2050 and even 2070 and “design for the future.”