Extreme Heat Resiliency Cambridge

New England is oft-associated with a “cold climate” label, however, the effects of climate change with regards to heat are already being felt today. The Greater Boston region has increasingly been exposed to dangerous heat waves, and the number of days above 90°F is projected to triple in the coming decades. 

 

As part of a broader suite of extreme heat mitigation strategies in its recently-published Resilient Cambridge plan, the city of Cambridge (MA) has been testing the efficacy of high albedo pavements and pavers as a climate change adaptation strategy. While implementation of ‘cool pavement’ projects have recently accelerated in Southwestern US cities’ extreme heat mitigation efforts (e.g., pilot projects in Phoenix, Los Angeles, Tucson), the city of Cambridge is one of the first cities to pilot such strategies in the Northeast.  

 

One such example is the city-owned Springfield Street parking lot, an asphalt surface that was recently coated by the Department of Public Works with a high Standard Reflectivity Index (SRI) paint coating with a color close to that of sandstone. The city is working with an engineering firm, Kleinfelder, to monitor surface and ambient air temperature benefits. Cambridge has since joined the Cool Roadways Partnership, a collaborative effort and co-learning initiative between global cities via Global Cool Cities Alliance (GCCA) and Smart Surfaces Coalition (SSC).

 

 

 

The city has also started to mainstream extreme heat into design considerations for public parks and open spaces. At Inman Square, they have incorporated high-albedo pavers to reduce urban heat island (UHI) effects. The city has also installed artificial shade structures, such as an educational pilot at Greene Rose Heritage Park.  

 

“As part of the Resilient Cambridge plan, the city is using a range of strategies to reduce the urban heat island effect,” says John Bolduc, Environmental Planner, City of Cambridge

 

Through its stormwater planning efforts, Cambridge has begun prioritizing candidate locations for green infrastructure that achieves multiple benefits beyond water quality, including localized flood mitigation and urban heat island mitigation.  For example, Kleinfelder – who led the development of Resilient Cambridge – is partnering with Stantec to mainstream UHI and flood mitigation into The Port [Neighborhood] Infrastructure Improvements project, a project which recently won an ACEC National Award. While the city project was primarily driven by water infrastructure upgrades, it was recognized early as an opportunity to implement green stormwater infrastructure and increase tree canopy to the maximum extent practicable as a means of also addressing UHI impacts.  The Port Neighborhood has one of the lowest percentages of tree canopy coverage in the city and has been modeled as a “hot spot” in the city’s UHI Technical Report and a priority within the city’s Urban Forest Master Plan.  

 

Beyond extensive tree planting efforts, a particular focus on strategies that maximize available soil storage volume for future root growth are needed to ensure more robust tree canopy development and future shade cooling benefits. The city has also recently adopted a green roof ordinance for new buildings larger than 25,000 square feet, and has been developing a ‘Cool Factor’ to combat extreme heat at the parcel/development level, based on the city’s Climate Resilience Zoning Task Force recommendations.

 

"One generation plants the trees, another gets the shade." - Chinese Proverb

 

The city has also prioritized communicating the benefits of such physical and social infrastructure initiatives to its residents, with the Resilient Cambridge website housing several heat storymaps, and a forthcoming ‘HeatViewer’ to supplement its’ rooftop albedo mapping and existing Heat Dashboard application.