Achieving global climate goals requires addressing whole life carbon emissions of buildings, encompassing both operational and embodied carbon—the often-overlooked emissions generated before residents even set foot in their buildings. This OECD report, Zero-Carbon Buildings in Cities: A Whole Life-Cycle Approach, brings whole life carbon to the forefront of the decarbonisation agenda. Based on a global survey of 18 countries and cities, it highlights best practices, proven strategies, and actionable insights for policy makers at all levels. By bridging a critical gap in sustainable building policies, this report equips countries and cities to accelerate the transition to zero-carbon buildings and build a more sustainable future.
Zero-Carbon Buildings in Cities
A Whole Life-Cycle Approach
OECD Urban Studies
Abstract
Executive Summary
The day-to-day use of buildings generates significant operational emissions (e.g. through lighting, heating and cooling) and recent decades have seen an acceleration in efforts to reduce these, notably as a response to climate change and more recently to the energy and cost of living crisis. However, these are not the only emissions to account for when calculating the overall carbon footprint of buildings. The production and the eventual demolition of buildings are also significant sources of emissions. These emissions, typically referred to as embodied carbon or embodied emissions, are expected to account for around half of the total carbon footprint of new buildings by 2050 if left unaddressed.
To achieve net-zero emission buildings, governments need to adopt a whole life-cycle approach, which addresses both operational and embodied carbon to reduce a building’s overall footprint. Whole life carbon, however, has, at least until recently, been a blind spot in global climate policy, despite the fact that much of the progress made on reducing operational emissions has arisen through the construction of newer, more energy‑efficient buildings. Indeed, reducing embodied emissions can also enhance resource efficiency, promote material circularity, and drive innovation in construction practices.
The new OECD Global Survey on Whole Life Carbon of Buildings aims to accelerate progress on embodied emissions by providing in‑depth insights on how to integrate whole life carbon approaches into regulatory frameworks and sustainable development strategies.
Numerous national and subnational policy measures are already in place. Key regulatory approaches include mandatory whole life carbon assessments and reporting, as well as the establishment of limit values for carbon emissions. Mandatory reporting frameworks, such as those in Germany, Sweden, and Greater London (UK), provide a foundation for compliance on and oversight of carbon emissions across all the different construction stages. Limit values, adopted by Denmark and France, for example, set clear maximum thresholds for emissions, encouraging innovation in low-carbon construction practices that can accelerate progress on climate goals.
At the same time, the effective implementation of these measures depends on several enabling factors. These include the development of standardised methodologies to ensure consistency and accuracy in carbon assessments, alongside the adoption of digital tools to support data collection and analysis. For example, Sweden’s climate declarations provide a standardised format for reporting climate data on upfront emissions (A1-A5 stages), while Singapore has a Green Mark certification to assess both operational and embodied carbon.
In addition, training and education programmes are crucial for building stakeholder capacity and raising awareness. For instance, France’s Massive Open Online Course (MOOC) on Sustainable Building platform trains project managers on RE2020 regulations (France’s standard for energy and environmental impact of buildings). Financial incentives can also help foster compliance and stimulate innovation. For example, Vancouver (Canada)'s NearZero programme, launched in 2018, provides subsidies to incentivise embodied carbon reduction and high-performance construction.
Complementary initiatives, such as voluntary certifications, are used in some countries to test industry readiness and establish benchmarks for sustainability before implementing regulations. For example, Germany’s Sustainable Building Quality Seal (QNG) is voluntary standards for greenhouse gas (GHG) emissions throughout a building’s life cycle. The QNG is verified by the Quality Assurance Association for Life-Cycle Assessment (LCA) Tools for Buildings e.V., whose aim is to test and confirm the quality of tools for standard-compliant and QNG-compliant LCAs for buildings using scientific methods. Circular economy approaches, like Malmö’s LFM30 platform in Sweden and Oslo’s guidelines for real estate developers in Norway, emphasise material reuse and waste reduction, integrating practices that lower embodied carbon and support sustainable construction goals.
However, several barriers persist, slowing the implementation of whole life carbon policies. This report outlines those barriers and provides targeted recommendations to overcome them.
1. Limited adoption of whole life carbon policies: Only 21% of countries that responded to the OECD Global Survey on Buildings and Climate currently implement policies that specifically target whole life carbon.
2. High complexity of setting reference and limit values: Developing whole life carbon benchmarks for diverse types of buildings is a complex task due to variations in building size, energy intensity and stock composition. This process requires extensive research and can be time-consuming.
3. Limited Environmental Product Declaration data: Limited availability of Environmental Product Declaration (EPD) data, which provide standardised information on the environmental impact of products, can lead to inaccurate whole life carbon assessment results. Construction product and material manufacturers can be reluctant to invest in environmental product declarations, largely because the expected return on investment is uncertain or low.
4. Stakeholder burden: Because buildings are composed of tens of thousands of parts, calculating whole life carbon can impose an onerous burden on developers, architects, and construction companies, especially in firms with limited expertise or human resources.
5. Resource and expertise constraints at the local level: Subnational governments, particularly municipalities and smaller cities, face significant institutional and capacity barriers in terms of implementing whole life carbon policies due to misaligned policies, workload pressures, and a shortage of experts within local authorities.
6. Absence of immediate direct co-benefit for end users in embodied carbon policies: Operational energy efficiency measures provide clear, direct advantages, including energy cost savings, improved health outcomes, and enhanced comfort for occupants. In contrast, addressing embodied carbon often imposes higher costs on construction stakeholders while offering limited tangible benefits for building owners and tenants. This economic imbalance can make whole life carbon initiatives less appealing compared to operational energy efficiency measures, as they lack the immediate co-benefits that drive stakeholder engagement and support. Consequently, these policies are unlikely to gain traction if left solely to market dynamics or public regulations alone.
1. Apply a whole life-cycle approach to shift focus from only operational carbon to also address energy efficiency and embodied carbon: Decarbonisation policies for buildings need to consider all aspects of construction – whether planning new buildings, undertaking renovations, or managing demolition and reconstruction. Tackling embodied carbon is particularly important for achieving immediate CO2 reductions critical to achieve mid-term goals (e.g. those set for 2030), while also laying the foundation for achieving long-term targets such as net-zero emissions by 2050. Notably, embodied emissions are projected to represent approximately half of the total carbon footprint of buildings by 2050 if left unaddressed.
2. Adopt a step-by-step approach to the implementation of whole life carbon policies: Long-term roadmaps should establish measurable goals and phased milestones, starting with relatively simpler measures such as mandatory climate impact reporting, which not only fosters stakeholder “buy-in” and engagement but also serve as a testing ground for more complex interventions. Over time, governments can introduce stricter emission limits and more complex interventions. Categorising buildings into different types (e.g., residential, commercial) allows for tailored benchmarks that reflect varying emission reduction potentials, as seen in France’s RE2020 regulation and Sweden’s phased whole life carbon strategy. Stakeholder engagement and public-private partnerships, exemplified by Denmark’s collaborative climate roadmaps and carbon limit regulations, are crucial to align efforts, mobilise resources, and ensure flexibility. This incremental approach balances ambition with practicality, fostering innovation and ensuring progress toward decarbonising diverse building stocks.
3. Develop strategies for data collection: Incentivising Environmental Product Declaration (EPD) acquisition and developing a digital platform for data sharing can help enable the creation of a national database. By consolidating accurate and standardised data, such a database helps inform decision-making, facilitate benchmarking, set clear reduction targets, and monitor progress. It can also promote transparency and collaboration across sectors, driving more effective and cohesive emissions reduction efforts. To overcome limited industry capacity for generating EPDs, countries such as the Netherlands and Denmark have introduced financial support programmes to incentivise manufacturers, while Denmark, France, Finland and Sweden have encouraged EPD use by setting more conservative generic emission data. This approach ensures that products without EPDs are assigned higher emissions values, effectively making EPD-certified products more advantageous.
4. Deploy digital tools to reduce workload: Developing comprehensive databases and standardised assessment tools such as the Netherlands' Nationale Milieudatabase, enables firms to conduct accurate and efficient whole life carbon assessment. Building Information Modelling (BIM) is critical for centralising data and automating whole life carbon assessments, but its adoption —especially among SMEs—remains limited. Initiatives like France's Plan BIM and Japan's BIM Acceleration Project demonstrate how financial support, training, and standardisation can promote widespread BIM use.
5. Enhance vertical co-ordination to empower city-led initiatives: Cities are uniquely positioned to lead ambitious initiatives that can drive significant emission reductions with their regulatory authority, proximity with stakeholders and ability to act as innovation hubs. For instance, cities like Tampere, Helsinki, and Vancouver have implemented stricter standards than national regulations and adopted innovative practices. To maximise their potential, national governments should establish coherent frameworks with standardised methodologies, accessible tools, and national databases, while creating platforms for regular information exchange with cities. Disparities in capacity, particularly in smaller cities, highlight the need for national support through funding, training, and tailored guidance. Effective national/local co‑ordination is essential to scale up individual cities’ successes nationally, fostering impactful whole life carbon policy implementation across all regions.
6. Strengthen horizontal collaboration and public-private-academic partnerships: Horizontal collaboration, such as Sweden’s inter-municipal and Japan’s inter-ministerial initiatives, promotes knowledge-sharing, aligns policies, and breaks down silos to advance coherent national roadmaps. Public-private-academic partnerships mobilise expertise for developing methodologies, databases, and pilot projects (e.g., Brazil’s SIDAC, Japan’s J-CAT) while addressing skill gaps through training programmes like Nordic Skills4Reuse. Early stakeholder mapping, as in the Netherlands’ NMD model, ensures clear roles and responsibilities, minimising conflicts and enabling efficient whole life carbon policy implementation.
