Cities are rapidly tackling the hidden emissions in how we build
Through shared commitment, cities are shifting from carbon-intensive construction to circular, retrofit-first approaches
Construction accounts for over 23% of global greenhouse gas emissions[1] and consumes more than 30% of global resources[2]. While cities have focused on making buildings energy-efficient in operation, the emissions generated throughout a building’s lifecycle from materials to demolition (embodied emissions) represent a growing share of buildings’ total carbon footprint.
By 2050, an additional 2.5 billion people will live in cities. Urban growth needs new buildings and infrastructure. If we stick to business-as-usual construction practices, we will lock in decades of high emissions and push global temperature rise beyond 3°C. This matters because the buildings we construct today will still be standing in 2050, presenting a critical choice: they will either add to dangerous global heating or help to secure a climate-safe future.
The C40 Clean Construction Accelerator unites eight cities to transform how they build. By joining this Accelerator, mayors are committing to:
- take collective action to reduce embodied emissions
- work with relevant stakeholders to establish joint roadmaps and set targets for embodied emission reduction
- set the standard by using the city’s purchasing power to demand low-carbon construction materials in public projects
Why cities are choosing clean construction
Mayors are transforming construction practices because addressing embodied emissions delivers climate impact while creating jobs and healthier communities.
Reuse, repurpose, and retrofit first, build new only when necessary
Keeping existing buildings instead of demolishing them
Demolishing and rebuilding wastes the embodied carbon already invested in existing structures. Retrofitting and repurposing existing buildings keeps investments safe and opens doors for energy efficiency upgrades. This approach also helps keep the community spirit of a neighbourhood. It protects affordable housing and creates good, green jobs in renovation and restoration.
Materials and construction machinery produce massive emissions
Moving beyond energy efficiency to address how buildings get built
The choices we make in how we design and construct buildings can be a huge driver of emissions. Carbon-intensive materials dominate construction today. Our signatory cities are changing common practice by requiring building design to use fewer resources and include more circular and biobased materials, which can also reduce climate impacts for residents.
Creating jobs in the circular economy
Reskilling workers for resource-efficient construction and retrofit
Clean construction means jobs in retrofitting and repurposing buildings, in material recovery, sustainable manufacturing, and installing low-carbon systems. Workers pick up new skills around circular design, waste reduction, and running emission-free equipment. It builds local expertise in areas that are expanding, rather than keeping people tied to carbon-intensive work.
Demanding transparency from the industry
Using data to drive change and showing leadership through procurement
Cities spend billions on construction projects. Requiring life cycle assessments in planning permissions, rewarding low-carbon materials in procurement, and demanding zero-emission construction machinery create market signals that shift the entire industry. Municipal leadership demonstrates what’s possible and builds supply chains that benefit all construction projects.
What cities commit to through the C40 Clean Construction Accelerator
Cities that join the C40 Clean Construction Accelerator commit to delivering on eight separate actions that bring together and inspire stakeholders to take the necessary action to transform to low-carbon construction practices.
In meeting these commitments, cities will set in motion the collective action necessary to:
- Reduce embodied emissions by at least 50% for all new buildings, major retrofits, and infrastructure projects by 2030.
- Require zero-emission construction sites citywide by 2030, where technology is available.
This transforms construction from a major source of emissions into a driver of circular economy innovation and green job creation. Cities achieve this through municipal leadership and policy action:
Commitment 1: Reuse-first approach
Prioritise the reuse, repurposing, and retrofit of existing buildings and infrastructure, ensuring optimal use before considering new construction projects.
Commitment 2: Municipal procurement leadership
Lead by example by requiring life cycle assessments and construction waste diversion for all municipal projects, procuring zero-emission construction machinery from 2030, where available, and rewarding resource-efficient design and low-carbon materials in municipal contracts.
Commitment 3: Transparency and accountability
Require life cycle assessments in planning permissions, embed them into building codes within one year of committing to the accelerator, and publicly disclose emissions data to build robust standards and foster industry accountability.
Commitment 4: Collaborative roadmaps
Work with businesses, industry, workers, and communities to establish joint roadmaps with interim targets toward 2030 goals within two years of committing to the accelerator, incorporating circular economy principles into Climate Action Plans.
Commitment 5: Flagship demonstration projects
Approve at least one net zero emission (operational and embodied) flagship project within two years of committing to the accelerator to demonstrate what’s possible and build local market capacity.
Commitment 6: Climate resilience assessment
Assess the impact material choices and construction design will have on cities’ overall resilience to climate impacts, including urban heat island effects and flooding risk from impermeable surfaces.
Commitment 7: Advocacy for government action
Work with and advocate for regional, national and supranational governments to take action on sources outside city boundaries.
Commitment 8: Annual progress reporting
Publicly report every year on progress cities are making towards these goals.
Cities committed to the C40 Clean Construction Accelerator
Budapest, London, Los Angeles, Mexico City, Milan, New York City, Oslo, San Francisco
How cities deliver on their clean construction commitments
Cities deliver through policy changes, procurement requirements, transparency standards, industry partnerships, and flagship projects that demonstrate clean construction in practice, and by fostering demand across the entire industry for low-carbon practices
Questions about the C40 Clean Construction Accelerator?
Cities interested in signing onto an Accelerator or learning more can contact the C40 Clean Construction Accelerator team at cleanconstruction@c40.org.
Related
This forum supports cities in driving the transition to resource-efficient, resilient and zero-emission construction by addressing the impacts of construction, such as emissions from materials extraction, manufacturing, assembly, transport, maintenance and end-of-life sorting.
Urban planning measures are critical for cities to be able to deliver on their greenhouse gas emissions reduction targets and reduce their vulnerability to climate hazards. C40’s Urban Planning work supports cities to develop, implement and share planning strategies and regulations that set a framework for sustainable and equitable urban growth.
Discover how mayors and cities worldwide are delivering on their commitments to take urgent climate action through C40’s High-Impact Accelerators.
