Data story: How embodied carbon benchmarks vary by building type, region, and material choice

Why It Matters

Buildings account for roughly 37 percent of global energy-related carbon emissions, yet nearly a quarter of a typical new building's lifetime carbon footprint is locked in before anyone flips on the lights. Embodied carbon, the emissions from extracting, manufacturing, transporting, and assembling building materials, represents between 20 and 50 percent of whole-life carbon depending on building type and climate zone (World Green Building Council, 2025). As operational energy efficiency improves through better envelopes and heat pumps, embodied carbon's share is rising. A 2025 analysis by the Carbon Leadership Forum found that for high-performance commercial offices meeting current energy codes, upfront embodied emissions already exceed 50 percent of the 60-year lifecycle total, making material selection the single largest lever for carbon reduction. Despite this urgency, benchmarking remains fragmented: the same reinforced-concrete office tower can carry an embodied carbon intensity of 350 kgCO2e/m² in Scandinavia or 620 kgCO2e/m² in Southeast Asia, depending on cement clinker ratios, grid carbon intensity of manufacturing, and transport distances (CLF, 2025). Understanding where these benchmarks cluster and what drives variance is critical for architects, developers, policymakers, and investors who need to set credible targets and allocate decarbonization budgets.

Key Concepts

Embodied carbon scope and lifecycle stages. The EN 15978 standard divides embodied carbon into modules: A1-A3 (product stage covering raw material extraction, transport to factory, and manufacturing), A4-A5 (transport to site and construction), B1-B5 (maintenance, repair, and replacement over building life), and C1-C4 (end-of-life demolition and disposal). Module D captures potential credits from reuse or recycling. Most published benchmarks focus on A1-A3 because data quality is highest, but this scope captures only 60 to 80 percent of total embodied carbon; excluding construction-stage waste (A5) and replacements (B4-B5) can understate impacts by 15 to 30 percent (RICS, 2024).

Benchmark databases. Several open and proprietary databases now aggregate project-level embodied carbon data. The Carbon Leadership Forum's Embodied Carbon in Construction Calculator (EC3) contained over 150,000 Environmental Product Declarations (EPDs) by late 2025. One Click LCA's global database spans more than 80,000 projects across 170 countries. The UK's Built Environment Carbon Database (BECD) published by LETI and the Greater London Authority collects whole-life carbon assessments from London planning submissions, with over 900 entries as of early 2026 (GLA, 2026). The RIBA 2030 Climate Challenge uses BECD data to set progressive targets.

Carbon intensity metrics. The standard unit is kilograms of CO2-equivalent per square meter of gross internal area (kgCO2e/m²). Infrastructure projects often use kgCO2e per functional unit, such as per lane-kilometer of road or per megalitre capacity of a water treatment plant. Comparing across building types requires normalizing by function, climate, and design life.

Material carbon intensity drivers. Cement and steel together account for roughly 15 percent of global CO2 emissions. Portland cement clinker produces about 0.6 to 0.9 tCO2 per tonne depending on kiln efficiency and fuel mix. Structural steel from blast furnace routes averages 2.0 tCO2/t globally, while electric arc furnace (EAF) steel using scrap averages 0.4 to 0.7 tCO2/t (World Steel Association, 2025). Mass timber products such as cross-laminated timber (CLT) can store more carbon than they emit during manufacturing, achieving net-negative A1-A3 values of minus 150 to minus 500 kgCO2e/m³ depending on forestry practices and transport (Athena Sustainable Materials Institute, 2024).

What's Working and What Isn't

Progress on data availability. The number of published EPDs has grown roughly 25 percent year-on-year since 2022, with the EC3 database surpassing 150,000 entries in 2025 (CLF, 2025). Mandatory whole-life carbon reporting in the Netherlands, France (RE2020), Denmark, and parts of Canada is generating large, comparable datasets. London's planning policy requiring whole-life carbon assessments for major developments has produced the densest benchmark dataset outside Scandinavia, enabling statistical analysis of building type and structural system effects (GLA, 2026).

Benchmark convergence for commercial offices. Data from BECD and the CLF show that new-build commercial offices cluster between 400 and 700 kgCO2e/m² for modules A1-A5, with median values around 500 kgCO2e/m² in Western Europe and 550 kgCO2e/m² in North America. Leading projects using optimized concrete mixes, high-recycled-content steel, and timber hybrid structures have achieved 250 to 350 kgCO2e/m², demonstrating that 40 to 50 percent reductions from median are technically feasible today (One Click LCA, 2025).

Residential benchmarks are lower but highly variable. Single-family residential construction in timber-frame traditions (Nordic countries, North America, Japan) shows A1-A5 intensities of 200 to 350 kgCO2e/m². Reinforced-concrete apartment buildings in southern Europe and Asia range from 400 to 700 kgCO2e/m². The structural system accounts for roughly 60 percent of this variance, with foundations and substructure contributing a further 15 to 25 percent depending on ground conditions (RICS, 2024).

Infrastructure remains under-benchmarked. Roads, bridges, tunnels, and water infrastructure have far fewer published benchmarks despite high material intensity. A 2025 study by the UK Infrastructure Carbon Review found that highway projects range from 40 to 120 tCO2e per lane-kilometer, with earthworks and concrete structures as the primary drivers. Water treatment plants show wide variance from 200 to 600 kgCO2e per megalitre of daily capacity depending on process complexity and materials. The absence of standardized functional units makes cross-project comparison difficult.

Regional grid carbon amplifies material differences. A concrete structure manufactured in Norway (grid factor ~20 gCO2/kWh) carries substantially lower embodied carbon than an identical structure in India (grid factor ~700 gCO2/kWh) because electricity-intensive processes like cement grinding, steel production, and aluminum smelting scale with grid carbon intensity. The World Steel Association (2025) reports that EAF steel produced in Sweden emits 0.3 tCO2/t versus 1.8 tCO2/t for the same process in Poland, driven almost entirely by grid differences.

Gaps in data quality and comparability. Despite progress, significant challenges remain. EPD quality varies: some use generic background data while others rely on facility-specific measurements. System boundaries differ between program operators, and allocation methods for co-products (like blast furnace slag used as cement replacement) are inconsistent. A 2024 RICS assessment found that the same building assessed by two different teams using different LCA tools could yield embodied carbon estimates differing by up to 40 percent due to methodological choices rather than genuine design differences.

Key Players

Established Leaders

• One Click LCA — Leading whole-life carbon assessment platform with 80,000+ projects across 170 countries and integration with major BIM tools.
• Arup — Global engineering consultancy with pioneering embodied carbon assessment capabilities and contributor to LETI and RIBA benchmarks.
• Skanska — Construction multinational with internal carbon pricing and published embodied carbon reduction targets across all markets.
• Holcim — World's largest cement producer investing in low-carbon binder technologies including LC3 and carbon-cured concrete.

Emerging Startups

• Tangible Materials — Platform providing real-time embodied carbon data from material suppliers, connecting EPDs to procurement decisions.
• Neocrete — Developing supplementary cementitious materials from industrial waste streams, claiming 50 percent clinker reduction.
• Brimstone Energy — Producing carbon-negative Portland cement from calcium silicate rock, eliminating process emissions from limestone calcination.
• CarbonCure Technologies — Injecting captured CO2 into fresh concrete during mixing, mineralizing it permanently while improving compressive strength.

Key Investors/Funders

• Breakthrough Energy Ventures — Bill Gates-backed fund investing in low-carbon cement and steel startups including Brimstone and Boston Metal.
• LETI (London Energy Transformation Initiative) — Volunteer network publishing embodied carbon targets and benchmarking guidance for the UK construction sector.
• ClimateWorks Foundation — Funding embodied carbon policy research and supporting the Carbon Leadership Forum's database and advocacy work.

Examples

Haut, Amsterdam (Team V Architecture / Arup). Completed in 2024, this 73-meter residential tower is one of the tallest timber hybrid buildings in Europe. By replacing a conventional reinforced-concrete structure with cross-laminated timber (CLT) cores and glulam columns, combined with low-carbon concrete for foundations, the project achieved an A1-A5 embodied carbon intensity of 290 kgCO2e/m², roughly 45 percent below the Dutch benchmark for residential towers. Arup's lifecycle analysis showed the timber structure sequestered approximately 1,800 tonnes of biogenic carbon, effectively offsetting all A1-A3 emissions from the concrete substructure. The project demonstrated that timber hybrid construction can meet fire, acoustic, and seismic performance requirements at high-rise scale while dramatically reducing embodied carbon.

Microsoft Silicon Valley Campus, Mountain View, California (Bjarke Ingels Group). Microsoft's 64,000 m² campus expansion, completed in 2025, set an internal embodied carbon budget of 350 kgCO2e/m² for modules A1-A5, approximately 35 percent below the North American commercial office median. The team used the EC3 tool to specify low-carbon concrete (averaging 40 percent cement replacement with slag and fly ash), EAF-sourced structural steel with over 90 percent recycled content, and mass timber for the roof structure. CarbonCure technology was applied to all ready-mix concrete, mineralizing 17 kg of CO2 per cubic meter. The final assessed intensity came in at 328 kgCO2e/m², within budget, and the project published its full Bill of Materials carbon data to the CLF database to support industry benchmarking (CLF, 2025).

Karolinska University Hospital, Stockholm (White Arkitekter). This 320,000 m² healthcare campus in Sweden, with phases completing between 2018 and 2025, represents one of the most comprehensive embodied carbon tracking efforts for a major institutional building. The final phase used EPD-verified low-carbon concrete with a 55 percent ground granulated blast furnace slag replacement, reducing concrete carbon intensity from 350 to 180 kgCO2e/m³. Combined with Sweden's low-carbon electricity grid powering local manufacturing, the hospital achieved an A1-A3 intensity of 270 kgCO2e/m² for a building type that typically benchmarks at 500 to 700 kgCO2e/m² globally. The project demonstrated that even highly serviced, equipment-intensive buildings can achieve deep reductions through systematic material specification (One Click LCA, 2025).

Action Checklist

• Set building-type-specific embodied carbon budgets using published benchmarks from BECD, CLF, or One Click LCA databases, targeting at least 40 percent below median for new projects.
• Require A1-A5 whole-life carbon assessments at each design stage (concept, detailed design, as-built), using consistent tools and system boundaries.
• Specify materials using EPDs and tools like EC3 to compare product-level carbon intensity; prioritize low-clinker concrete, EAF steel, and sustainably sourced mass timber.
• Integrate embodied carbon targets into procurement contracts with measurable clauses and verification requirements for material suppliers.
• Benchmark completed projects and contribute anonymized data to open databases (EC3, BECD) to improve industry-wide benchmark quality.
• Advocate for mandatory whole-life carbon reporting in local planning policy, following precedents set by London, the Netherlands, France, and Denmark.
• Evaluate regional supply chain carbon intensity including grid factors and transport distances when assessing material choices for specific project locations.

FAQ

What is a good embodied carbon target for a new commercial office building? Based on 2025 benchmark data from the CLF and BECD, the median A1-A5 embodied carbon for new commercial offices in Western Europe sits around 500 kgCO2e/m². Leading projects achieve 250 to 350 kgCO2e/m² through optimized structural systems, low-carbon concrete, high-recycled-content steel, and timber hybrid elements. A reasonable stretch target for a new project would be 350 kgCO2e/m² or below, representing roughly a 30 percent reduction from median. The LETI 2030 target for commercial buildings is 300 kgCO2e/m² for A1-A5, and RIBA's 2030 Climate Challenge sets similar progressive thresholds.

Why do embodied carbon benchmarks vary so much between regions? Three factors drive regional variance. First, electricity grid carbon intensity affects manufacturing emissions for energy-intensive materials like steel, aluminum, and cement. A tonne of EAF steel made in Norway has roughly one-sixth the carbon footprint of the same product made in Poland. Second, dominant construction traditions matter: countries with established timber-frame building cultures (Scandinavia, Canada, Japan) show lower residential benchmarks than those relying on reinforced concrete (Southern Europe, Asia). Third, regulatory environments influence material availability, with markets that mandate EPDs and set carbon limits (France, Netherlands, Denmark) seeing faster adoption of low-carbon alternatives.

How reliable are Environmental Product Declarations (EPDs) for benchmarking? EPDs provide the best available product-level carbon data, but quality varies. Facility-specific EPDs based on measured production data are more reliable than industry-average EPDs. Differences in background databases, allocation methods for co-products, and system boundary assumptions can cause the same product to yield different results across EPD program operators. RICS (2024) found that methodological choices alone can create up to 40 percent variance in building-level assessments. To improve reliability, practitioners should prefer facility-specific EPDs verified by accredited third parties, use consistent LCA tools across project phases, and apply sensitivity analysis to key assumptions.

Can mass timber really achieve carbon-negative embodied carbon values? Sustainably sourced mass timber products can achieve net-negative A1-A3 values when biogenic carbon sequestered during tree growth is credited according to standards like EN 15804. CLT and glulam typically store 500 to 900 kgCO2/m³ of biogenic carbon while manufacturing emissions (sawmill energy, adhesives, transport) range from 50 to 200 kgCO2/m³, yielding net values of minus 150 to minus 500 kgCO2e/m³ (Athena, 2024). However, this accounting depends on sustainable forest management ensuring replanting and carbon stock maintenance, long building lifespans preventing premature release, and end-of-life pathways that avoid incineration. Critics note that biogenic carbon accounting methods vary between standards and that crediting sequestration can obscure supply chain emissions.

What role does concrete play, and how much can its carbon be reduced? Concrete is the most widely used building material by volume and contributes roughly 8 percent of global CO2 emissions. The primary source is cement clinker production, which releases CO2 from both limestone calcination and fuel combustion. Standard Portland cement (CEM I) produces 0.8 to 0.9 tCO2/t. Proven reduction strategies include replacing clinker with supplementary cementitious materials (fly ash, slag, calcined clay), reducing cement content through mix optimization, and using carbon-cured concrete technologies. These approaches can reduce concrete carbon intensity by 30 to 60 percent today. Emerging technologies like Brimstone's calcium silicate cement and electrochemical processes could eventually eliminate process emissions entirely, but remain at pilot scale.

Sources

• Carbon Leadership Forum. (2025). EC3 Database Annual Report: EPD Coverage, Benchmark Trends, and Embodied Carbon Trajectories. University of Washington.
• World Green Building Council. (2025). Bringing Embodied Carbon Upfront: Coordinated Action for the Building and Construction Sector. WorldGBC.
• Greater London Authority. (2026). London Built Environment Carbon Database: Whole-Life Carbon Benchmark Analysis 2023-2025. GLA Planning.
• RICS. (2024). Whole Life Carbon Assessment for the Built Environment: Second Edition. Royal Institution of Chartered Surveyors.
• One Click LCA. (2025). Global Embodied Carbon Benchmark Report: Commercial, Residential, and Infrastructure Projects. One Click LCA.
• World Steel Association. (2025). Steel's Contribution to a Low-Carbon Future: Lifecycle Data and Regional Carbon Intensity. Worldsteel.
• Athena Sustainable Materials Institute. (2024). A Cradle-to-Gate Life Cycle Assessment of Canadian Softwood Lumber and Cross-Laminated Timber. Athena SMI.
• UK Infrastructure Carbon Review. (2025). Benchmarking Embodied Carbon in UK Highway and Water Infrastructure Projects. Infrastructure and Projects Authority.