Heat Resilient Zoning
As the climate continues to change, extreme heat events are becoming increasingly frequent and intense. Considered the deadliest form of extreme weather in the United States, heatwaves present a multifaceted threat to public health, safety, and well-being. Beyond the immediate health implications—such as heatstroke, dehydration, and even fatalities—extreme heat has the potential to disrupt essential infrastructure including electricity grid, water, and transportation. Moreover, it is important to note that the impacts of heat are not equitably distributed- developed areas often experience what is called “Urban Heat Island” (UHI) effect where buildings, roads, and concrete absorb heat during the day and re-emit it overnight. UHI can cause urban areas to be several degrees hotter compared to surrounding areas, including at nighttime. For more information see EPA’s Urban Heat Island resources. In Massachusetts, Environmental Justice communities often bear a disproportionate exposure to extreme heat and lack of access to affordable cooling options at home or outdoors. To learn more about extreme heat see: Rising Temperatures and Extreme Heat in Greater Boston – MAPC.
Land use planning, policies and zoning can be used to reduce UHI and better prepare the community for extreme heat by improving the built environment, green space, and the quality of housing and buildings.
This page provides short summaries of key features of regulations based on desktop review. Links to the regulations are provided below. Conduct careful review when considering adopting new language. The resources included do not constitute legal advice. Municipalities should consult legal counsel when adopting new bylaws, ordinances, and policies.
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Language Examples
Additional Resources
Strategies to Strengthen Heat Resilient Zoning Requirements
Several municipalities in MA have adopted performance-based development standards that incentivize the use of “green” or sustainable elements into the site plan.
Somerville, MA
Green Score (zoning ordinance section 10) “Purpose: To incentive urban landscape elements that manage storm water, filter pollutants, reduce the urban heat island, provide habitat, sequester carbon dioxide, and improve air quality.” It has a performance-based standard for green infrastructure as part of the site plan standards (10.4), and a section on Heat Island Reduction (10.10) with a required solar reflectance for roofs and surface parking.
Cambridge, MA
Climate Resilient Zoning (22.90) plans for both flood resilience and extreme heat, including a Green Factors Standard which is a performance-based standard to incentivize green and sustainable development. This includes a target “cool score” for the development.
Several municipalities, including the City of Boston, have Green Building standards that include “LEED certifiable” buildings at certain threshold. LEED certification and other building performance standards provide credits for either green roofs or cool roofs.