Explainer: Embodied carbon measurement and reduction — what it is, why it matters, and how to evaluate tools

Why It Matters

Buildings and construction account for 37 percent of global energy-related CO₂ emissions, and roughly 11 percent of that total is embodied carbon: the greenhouse gases released during material extraction, manufacturing, transport, construction and end-of-life disposal (UNEP Global Alliance for Buildings and Construction, 2024). As operational energy efficiency improves through heat pumps, better insulation and renewable electricity, embodied carbon's share of a building's whole-life footprint is rising. For a typical new-build designed to near-zero operational standards, embodied carbon can represent 50 to 80 percent of lifecycle emissions (World Green Building Council, 2025). Unlike operational emissions, which can be reduced over decades through retrofit and grid decarbonisation, embodied carbon is locked in at the point of construction. Every tonne of cement, steel or aluminium specified today carries a carbon debt that cannot be reversed. With the global building stock expected to double by 2060, primarily in rapidly urbanising regions of Asia and Africa (IEA, 2024), early intervention on embodied carbon is one of the most time-sensitive climate actions available.

Key Concepts

Embodied carbon. The total greenhouse gas emissions associated with materials and construction processes throughout the lifecycle of a building or infrastructure asset. This includes raw-material extraction (life-cycle stage A1), transport to factory (A2), manufacturing (A3), transport to site (A4), construction (A5) and, where assessed, maintenance, replacement, demolition and disposal (stages B and C). Stage D covers benefits from reuse and recycling beyond the system boundary.

Whole-life carbon (WLC). The sum of embodied carbon and operational carbon over a building's reference study period, typically 50 or 60 years. Leading frameworks such as the RICS Whole Life Carbon Assessment (2nd edition, 2023) and the EU Level(s) framework require WLC assessments to prevent burden-shifting between embodied and operational emissions.

Environmental Product Declarations (EPDs). Third-party verified documents that disclose the environmental impacts of a construction product based on lifecycle assessment (LCA). EPDs follow ISO 14025 and EN 15804+A2 standards and provide the material-level data needed to calculate building-level embodied carbon. The number of construction EPDs registered globally surpassed 120,000 by the end of 2025, a 40 percent increase over 2023 (EPD International, 2025).

Upfront carbon. A subset of embodied carbon covering stages A1 to A5 only. Because upfront carbon is emitted before a building is even occupied, many policies and benchmarks focus on this metric as the most actionable lever.

Carbon intensity benchmarks. Expressed in kgCO₂e per square metre, benchmarks vary by building type and region. The Carbon Leadership Forum's Embodied Carbon Benchmark Study (2024) established median upfront carbon intensities of approximately 350 kgCO₂e/m² for commercial offices, 290 kgCO₂e/m² for multi-family residential and 500 kgCO₂e/m² for healthcare facilities in North America. The LETI Climate Emergency Design Guide sets a 2030 target of under 300 kgCO₂e/m² (A1 to A5) for all building types in the UK.

Buy Clean policies. Procurement-led policies that set maximum Global Warming Potential (GWP) limits for key construction materials purchased with public funds. The US federal Buy Clean initiative, expanded in 2024, covers steel, concrete, asphalt and flat glass procured for federally funded projects (White House, 2024). Similar policies have been enacted in California, Colorado, the EU and several Canadian provinces.

What's Working

Regulatory momentum is creating market signals. France's RE2020, in force since 2022, is the world's first mandatory whole-life carbon regulation for new buildings, with limits that tighten every three years. Denmark followed with its building carbon limit of 12 kgCO₂e/m²/year (over 50 years) for buildings above 1,000 m², effective from 2025 (Danish Transport, Building and Housing Authority, 2024). The Netherlands is implementing a similar mandatory WLC cap. These policies demonstrate that regulation can shift material choices at scale: French developers report a 15 to 25 percent reduction in average upfront carbon for new residential buildings in the first two years of RE2020 compliance (CSTB, 2025).

Tool maturity is lowering barriers to measurement. Platforms such as One Click LCA, Tally and the free open-source EC3 (Embodied Carbon in Construction Calculator) by Building Transparency have made early-stage carbon estimation accessible to architects and engineers. One Click LCA reported over 50,000 active projects on its platform by mid-2025. EC3 holds over 130,000 EPDs and enables material-level comparison at the specification stage. These tools integrate with BIM workflows, allowing carbon optimisation alongside cost and structural design.

Low-carbon materials are scaling. Global production capacity for low-carbon cement alternatives (including calcined clay blends, geopolymers and supplementary cite materials) grew by an estimated 18 percent in 2024 and 2025 combined (Global Cement and Concrete Association, 2025). Nucor and SSAB are shipping near-zero-emission steel produced with electric arc furnaces and hydrogen direct reduction, with SSAB delivering its first commercial fossil-free steel batches to construction customers in 2025 (SSAB, 2025). Mass timber construction continues to expand, with cross-laminated timber (CLT) production capacity in North America doubling between 2022 and 2025.

Industry benchmarks are enabling target-setting. The Carbon Leadership Forum's open dataset of over 2,300 building-level assessments allows design teams to compare their projects against peer buildings by type, region and structural system. This data infrastructure underpins stretch targets and enables evidence-based procurement specifications.

Key Players

Established Leaders

• One Click LCA — Market-leading cloud platform for building lifecycle assessment, used in over 170 countries with integrations for Revit, Rhino and IFC files.
• Building Transparency — Non-profit behind the EC3 tool and the largest open database of construction EPDs, supported by over 60 industry partners.
• RICS — Published the globally adopted Whole Life Carbon Assessment methodology, now in its second edition.
• World Green Building Council — Coordinates the Advancing Net Zero programme and the global embodied carbon call to action.

Emerging Startups

• Tangible — Real-time embodied carbon optimisation integrated into early-design BIM workflows, enabling architects to compare structural options within minutes.
• 2050 Materials — AI-powered platform that aggregates material sustainability data from EPDs, manufacturer disclosures and LCA databases for rapid benchmarking.
• CarbonCure Technologies — Injects captured CO₂ into fresh concrete during mixing, reducing cement content while maintaining strength; deployed at over 800 plants globally.
• Brimstone — Produces ordinary Portland cement from calcium silicate rock instead of limestone, eliminating process emissions; raised US$189 million in Series B funding in 2024.

Key Investors & Funders

• Breakthrough Energy Ventures — Backed multiple low-carbon materials startups including CarbonCure and Brimstone.
• Laudes Foundation — Major funder of the Built Environment programme driving industry transformation and policy advocacy for embodied carbon regulation.
• ClimateWorks Foundation — Supports research and advocacy on building decarbonisation, including the Carbon Leadership Forum's benchmark studies.

Examples

Skanska and the Waterfront South project, London. Skanska used One Click LCA to model and optimise the embodied carbon of a 25-storey commercial tower in London's South Bank district. By substituting 50 percent of Portland cement with ground granulated blast-furnace slag, specifying UK-sourced recycled steel reinforcement and designing for material efficiency with post-tensioned concrete slabs, the team achieved a 40 percent reduction in upfront carbon compared with a conventional baseline, bringing the building below 250 kgCO₂e/m² (Skanska, 2025).

Microsoft campus expansion, Redmond, Washington. Microsoft's campus redevelopment programme mandated whole-life carbon assessments for all new buildings starting in 2023. Working with the Carbon Leadership Forum, the design teams evaluated over 300 EPDs per building and selected mass timber hybrid structures for two mid-rise office buildings. Microsoft reported that the timber buildings achieved 30 percent lower embodied carbon than equivalent steel-framed alternatives while storing approximately 3,500 tonnes of biogenic carbon in the structural system (Microsoft, 2024).

Copenhagen school buildings, Denmark. Under Denmark's new carbon limits, the City of Copenhagen required all new municipal buildings to meet an upfront carbon target of 8 kgCO₂e/m²/year, 33 percent below the national threshold. For two new school buildings completed in 2025, designers used prefabricated CLT wall and floor panels, recycled-aggregate concrete foundations and bio-based insulation. Lifecycle assessments showed upfront carbon of 210 kgCO₂e/m², roughly 40 percent below the national median for educational buildings (City of Copenhagen, 2025).

Holcim and ECOPact concrete. Holcim's ECOPact range, launched globally in 2020, offers concrete with 30 to 100 percent lower carbon intensity than standard mixes, achieved through clinker substitution and optimised mix designs. By the end of 2025, ECOPact accounted for 15 percent of Holcim's ready-mix volumes in Europe, with over 25 million cubic metres delivered across 20 countries (Holcim, 2025). Third-party EPDs for ECOPact products allow specifiers to quantify exact savings in their building-level models.

Action Checklist

• Set an embodied carbon target at project inception. Use benchmarks from the Carbon Leadership Forum or LETI as starting points and define a kgCO₂e/m² cap before detailed design begins.
• Require EPDs in procurement specifications. Mandate product-specific or manufacturer-specific EPDs for all major structural and envelope materials, not just industry-average data.
• Integrate carbon assessment into BIM workflows. Deploy tools such as One Click LCA, Tally or EC3 so that carbon is evaluated alongside cost and structural performance at every design stage.
• Prioritise upfront carbon reduction strategies. Specify low-carbon concrete mixes, recycled or low-emission steel, mass timber where appropriate and bio-based insulation. Optimise structural systems to reduce total material quantities.
• Design for disassembly and reuse. Use reversible connections, modular components and material passports to enable future material recovery and reduce end-of-life emissions.
• Benchmark against peers. Submit project data to open databases like the CLF Benchmark or EPIC (in Australia) to contribute to industry learning and track your portfolio's trajectory.
• Engage the supply chain. Work with concrete suppliers, steel fabricators and timber producers to source lower-carbon alternatives and request transparent environmental data.
• Monitor regulatory developments. Track Buy Clean policies, national WLC limits and green public procurement requirements in your operating jurisdictions to stay ahead of compliance deadlines.

FAQ

What is the difference between embodied carbon and operational carbon? Operational carbon covers the emissions from energy consumed during a building's use, including heating, cooling, lighting and plug loads. Embodied carbon covers everything else: the emissions from extracting, manufacturing, transporting and assembling the materials that make up the building, plus eventual demolition and disposal. As grids decarbonise and buildings become more energy-efficient, embodied carbon becomes a proportionally larger share of whole-life emissions.

Which building materials contribute the most to embodied carbon? Concrete and steel together typically account for 60 to 80 percent of a building's upfront embodied carbon. Cement production alone is responsible for roughly 8 percent of global CO₂ emissions (Global Cement and Concrete Association, 2025). Aluminium, glass and insulation materials are secondary contributors. Reducing clinker content in concrete and sourcing electric-arc-furnace steel or recycled steel are among the most impactful material substitution strategies.

Are embodied carbon tools accurate enough for regulatory compliance? Tool accuracy depends heavily on data quality. Building-level results can vary by 10 to 30 percent depending on whether project-specific EPDs, manufacturer-average data or generic database values are used (Carbon Leadership Forum, 2024). Regulatory frameworks typically mandate the use of product-specific or manufacturer-specific EPDs to narrow uncertainty. Teams should document data sources, assumptions and system boundaries transparently. Despite these limitations, current tools are sufficiently robust to guide material selection, set meaningful targets and demonstrate regulatory compliance.

How much does an embodied carbon assessment cost? For a mid-size commercial building, a standalone whole-life carbon assessment by a specialist consultant typically costs between US$15,000 and US$40,000, depending on complexity and the number of design iterations. However, when integrated into existing BIM workflows using tools like One Click LCA or Tally, marginal costs are significantly lower because the structural model already contains the necessary quantity data. Many firms report that integrating carbon assessment into standard design processes adds less than 0.1 percent to total project fees.

Can embodied carbon reductions increase construction costs? Not necessarily. Many high-impact strategies, such as structural optimisation to reduce material quantities, cement substitution with supplementary cementitious materials and specifying locally sourced materials, are cost-neutral or even cost-saving. Low-carbon concrete mixes using fly ash or slag are often cheaper than high-clinker alternatives. Mass timber can reduce construction time and foundation costs for mid-rise buildings. Where a cost premium exists, such as for fossil-free steel, it is typically 5 to 15 percent at the material level but less than 1 to 2 percent of total building cost, and these premiums are declining as production scales.

Sources

• UNEP Global Alliance for Buildings and Construction. (2024). 2024 Global Status Report for Buildings and Construction. United Nations Environment Programme.
• World Green Building Council. (2025). Advancing Net Zero: Whole Life Carbon in the Built Environment. WorldGBC.
• International Energy Agency. (2024). Global Energy and Climate Outlook: Buildings Sector. IEA.
• EPD International. (2025). Annual Report: Global EPD Programme Statistics. EPD International AB.
• Carbon Leadership Forum. (2024). Embodied Carbon Benchmark Study: North American Buildings Database. University of Washington.
• Danish Transport, Building and Housing Authority. (2024). Building Carbon Limits: Implementation Guidance for BR18. Danish Ministry of Transport.
• CSTB. (2025). RE2020 Impact Assessment: Upfront Carbon Reductions in French Residential Buildings, 2022-2024. Centre Scientifique et Technique du Bâtiment.
• White House. (2024). Federal Buy Clean Initiative: Expanded Material Categories and GWP Limits. Executive Office of the President.
• Global Cement and Concrete Association. (2025). Concrete Future: 2025 Progress Report on Net Zero Roadmap. GCCA.
• SSAB. (2025). Fossil-Free Steel: First Commercial Deliveries and Production Scale-Up. SSAB.
• Skanska. (2025). Waterfront South: Embodied Carbon Reduction Case Study. Skanska UK.
• Microsoft. (2024). Campus Modernisation: Mass Timber and Whole-Life Carbon Assessment. Microsoft Sustainability Report.
• City of Copenhagen. (2025). Climate-Neutral Municipal Buildings: School Building Programme Results. City of Copenhagen Technical and Environmental Administration.
• Holcim. (2025). ECOPact Low-Carbon Concrete: Global Deployment and Impact Report. Holcim Group.