Mayor Michelle Wu announced the approval of an amendment to the City’s zoning code by the Boston Zoning Commission to include Net Zero Carbon (NZC) Zoning. This new zoning will introduce decarbonization requirements for development projects that accelerate progress on the City’s goal of being carbon-neutral by 2050. Additionally, it will help Boston lead in the transition to a sustainable, low-carbon future for both building materials and energy. Under NZC, most new large buildings permitted and delivered will emit net zero carbon emissions from the day they open. 

“Around the world and here at home, the dangers of climate change are clear and intensifying. To protect families across our neighborhoods and keep our city running, we need urgent action to ensure resiliency for the safety and well-being of all Bostonians,” said Mayor Michelle Wu. “By embedding sustainability into new projects, we set Boston on a direct path towards a cleaner and healthier future for generations to come.” 

Buildings account for nearly 71 percent of our community’s carbon emissions and by adjusting operational performance requirements of new buildings, Boston can minimize emissions and its impact on climate. This includes reducing energy use, easing our reliance on fossil fuels, increasing electrification, and using renewable energy sources. NZC Zoning introduces a net zero emissions standard for new project filings after July 1, 2025, with 15 units or more, a minimum of 20,000 square feet, or additions of a minimum of 50,000 square feet or more to existing buildings. Projects will demonstrate compliance with this standard during Article 80 Development Review moving forward. Additionally, Small and Large Projects, as defined in Article 80, will be required to report on embodied carbon, which is the carbon emitted construction of a building and the manufacturing of its materials. Large Projects will also be required to conduct an embodied CO2e emissions life cycle assessment analysis. These amendments build upon and better reflect updated state building codes and city ordinances, including the Specialized Stretch Energy Code and Building Emissions Reduction and Disclosure Ordinance (BERDO), respectively. 

“This zoning is the first of its kind that will ensure that all new buildings achieve net zero operational emission. It is the right thing to do, and it will make Boston more competitive in the future,” said Chief of Planning Kairos Shen. “Thank you to our partners in the development community for working with us to keep building a healthy, green, and growing city.”

“This Net Zero Carbon Zoning policy represents a tremendous step forward in reducing Boston’s carbon footprint by requiring most major new buildings from now on to be net carbon neutral in operations from the moment they open,” said Brian Swett, Chief Climate Officer. “By addressing both operational and embodied carbon in new developments, we’re not only tackling emissions but also beginning to understand and reduce the carbon intensity of our building materials. We are deeply grateful to the real estate community for their partnership and willingness to align with the City’s climate action goals, ensuring a resilient and equitable Boston for generations to come.”

The NZC Zoning policy excludes renovations, additions under 50,000 square feet, and changes of use, encouraging large-scale adaptive reuse projects that combine energy efficiency upgrades. This policy allows for a phased in approach for hospitals, general manufacturing sites and labs. Recognizing the unique energy and ventilation needs of labs and hospitals, new labs will be required to meet net zero emissions by 2035, and new hospitals and general manufacturing buildings must meet net zero emissions by 2045. The NZC Zoning policy will ensure that Boston’s newest, state-of-the art buildings maximize their impact on greenhouse gas emissions reductions. If this policy had been in effect for large buildings beginning operation in 2023, it would have reduced Boston’s total annual greenhouse gas emissions by 0.58%, which is equivalent to all waste-related emissions in the city.

"We are proud to be a part of a community that challenges us all to imagine and build a better future," said Principal of Millennium Partners Boston Joe Larkin. "As the developer of Winthrop Center, the most energy efficient large scale office building that can be built in a cold weather climate, we applaud the City's leadership in decarbonization."

“On behalf of the Environmental League of Massachusetts Action Fund, we greatly appreciate the work done by the Wu Administration and the members of this Commission to provide the best outcome for resilient and efficient housing,” said Casey Bowers, Executive Director of the Environmental League of Massachusetts. “To this end, we need to address the largest source of emissions in Boston, our buildings. While we are working to decarbonize, an efficient place to start is new construction. Beginning with this Amendment, Boston can take a step to safeguard its future.”

“By making new large buildings net-zero emissions immediately with this policy, we accelerate BERDO’s timeline and avoid costly retrofits. We also improve air quality, keeping our families healthier,” said Hessann Farooqi, Executive Director of the Boston Climate Action Network. “When we build the right way, we chart a faster, less expensive course to fight climate change. I’m thrilled that Boston is taking this historic step, creating a model for cities everywhere. I am deeply grateful to Mayor Wu and our City Hall partners, as well as the incredible housing developers, residents, and businesses who made this vision a reality.”

“We are ecstatic to see the Boston Zoning Commission be climate leaders and adopt this important building code requirement. The adoption of this code will improve air quality for our children and community, protect our long term economic interests, and keep Boston on track to reach its greenhouse gas reduction goals,” said Andee Krasner, a Boston leader for Mothers Out Front. “We appreciate Mayor Wu's leadership and her team’s tireless work, and the contributions of countless Boston architects, engineers, and developers who helped make this ground-breaking policy possible.”

“By embedding carbon requirements within the zoning by-laws, Boston will be leading the way with a groundbreaking initiative focused on reducing carbon,” said Rickie Harvey, environmental advocate. “NZC Zoning addresses important carbon issues left out of the building codes: allowing for offsets and procurements and taking into account embodied carbon, emissions from construction, and life cycle analysis. All of these are crucial to correctly evaluating the costs and impacts of new construction. The NZC Zoning update puts in place a pillar of Mayor Wu’s promised Green New Deal while illustrating her leadership and willingness to break new ground in order to achieve important results.”

The approval of this policy by the Zoning Commission marks a significant milestone in Boston’s climate action efforts. It reinforces Mayor Wu’s commitment to reducing emissions, enhancing energy efficiency, and prioritizing sustainability in all aspects of urban development. As Boston progresses toward its 2050 carbon neutrality target, policies like NZC Zoning are vital to achieving a greener, healthier, and more equitable city for all.