Explainer: Embodied carbon in real estate & construction — what it is, why it matters, and how to evaluate options

Buildings account for roughly 37% of global energy-related CO2 emissions, but when most professionals hear "building emissions" they think of heating, cooling, and lighting. These operational emissions have dominated policy for decades, yet a quieter and equally significant category has been hiding in plain sight: embodied carbon. As operational efficiency improves through heat pumps, LED lighting, and tighter envelopes, the carbon locked into materials and construction processes has grown from an afterthought to the single largest share of a new building's lifetime carbon footprint. For sustainability professionals in real estate and construction, understanding embodied carbon is no longer optional. It is foundational.

Why It Matters

The built environment consumes approximately 50% of all extracted raw materials globally and generates roughly 23% of global CO2 emissions from industrial processes tied to material production alone, according to the United Nations Environment Programme's 2024 Global Status Report for Buildings and Construction. Cement production is responsible for about 8% of global CO2 emissions, and steel manufacturing contributes another 7-9%. These emissions occur before a building is ever occupied.

The urgency is amplified by timing. Operational carbon can be reduced over a building's 50 to 80 year lifespan through equipment upgrades and renewable energy sourcing. Embodied carbon, by contrast, is overwhelmingly locked in at the point of construction. Approximately 50-70% of a new building's embodied emissions are released during material manufacturing and construction, with the remainder tied to maintenance, replacement, and eventual demolition. Once concrete is poured and steel is erected, those emissions cannot be recaptured.

Regulatory momentum has accelerated sharply. The European Union's revised Energy Performance of Buildings Directive (EPBD), finalized in 2024, requires whole-life carbon assessments for all new buildings above 1,000 square meters by 2028 and for all new buildings by 2030. In North America, California's Buy Clean Act mandates Environmental Product Declarations (EPDs) for structural steel, concrete, and flat glass procured for state projects, with maximum Global Warming Potential (GWP) limits that tighten through 2027. The Federal Buy Clean Initiative, launched in 2022, extends similar requirements to federally funded infrastructure. New York City's Local Law 154 requires EPDs for concrete, steel, and other materials used in city-funded projects. Vancouver's embodied carbon policy, effective since 2025, requires all new buildings to report and reduce upfront carbon emissions.

For real estate developers and investors, the financial implications are mounting. GRESB now incorporates embodied carbon metrics into its real estate benchmarking, affecting portfolio-level ESG ratings. The Carbon Risk Real Estate Monitor (CRREM) includes embodied carbon pathways in its stranding risk assessments. Institutional investors managing over $4.5 trillion in real estate assets have committed to net-zero carbon portfolios by 2050 under the Net Zero Asset Managers initiative, and achieving those targets requires confronting embodied carbon head-on.

Key Concepts

Embodied Carbon refers to the total greenhouse gas emissions associated with the materials and construction processes throughout the entire lifecycle of a building, excluding operational energy use. This encompasses raw material extraction, transportation to manufacturing facilities, the manufacturing process itself, transport to construction sites, on-site construction activities, maintenance and material replacement over the building's service life, and eventual demolition and disposal or recycling. The standard unit of measurement is kilograms of CO2 equivalent per square meter (kgCO2e/m2) for whole buildings, or kgCO2e per unit of material for individual products.

Whole-Life Carbon (WLC) represents the complete greenhouse gas footprint of a building across its full lifecycle, combining both embodied carbon and operational carbon. As building codes push operational energy toward zero through electrification and on-site renewables, embodied carbon's share of WLC has risen from approximately 20-30% in conventional buildings to 45-65% in high-performance and net-zero energy buildings. For a typical new office building in North America, embodied carbon now accounts for 35-50% of whole-life emissions over a 60-year reference study period.

Environmental Product Declarations (EPDs) are standardized, third-party verified documents that quantify the environmental impacts of a specific product or material across defined lifecycle stages. Governed by ISO 14025 and EN 15804+A2, EPDs provide the raw data necessary for building-level embodied carbon assessments. Product-specific EPDs based on actual manufacturing data are significantly more accurate than industry-average EPDs, which can overestimate or underestimate impacts by 20-40%. As of 2025, over 150,000 EPDs are registered globally, though coverage remains uneven across material categories and regions.

Life Cycle Assessment (LCA) is the analytical methodology used to calculate embodied carbon at the building level. Governed by ISO 14040/14044 and applied through EN 15978 or its North American equivalent ASTM E2921, LCA quantifies environmental impacts across defined lifecycle stages labeled A1-A3 (product stage), A4-A5 (construction), B1-B5 (use stage maintenance and replacements), C1-C4 (end of life), and D (benefits beyond the system boundary from reuse or recycling). Whole-building LCA tools such as One Click LCA, Tally, and Athena Impact Estimator for Buildings enable project teams to model and compare design alternatives.

Carbon Sequestration in Bio-Based Materials occurs when timber, bamboo, hemp, straw, and other plant-based construction materials store atmospheric carbon captured during growth. Mass timber products such as cross-laminated timber (CLT) and glued laminated timber (glulam) sequester approximately 1.0-1.2 tonnes of CO2 per cubic meter of wood. This biogenic carbon storage can partially or fully offset the manufacturing emissions of bio-based materials, though the permanence of sequestration depends on building service life and end-of-life treatment. Current standards treat biogenic carbon storage differently across frameworks, creating inconsistencies that complicate cross-jurisdictional comparisons.

Embodied Carbon Benchmarks by Building Type

Building Type	Below Average	Average	Above Average	Best Practice
Office (kgCO2e/m2)	>800	500-800	350-500	<350
Residential Multi-Family (kgCO2e/m2)	>600	400-600	250-400	<250
Warehouse/Logistics (kgCO2e/m2)	>400	250-400	150-250	<150
Healthcare (kgCO2e/m2)	>1,200	800-1,200	550-800	<550
Education (kgCO2e/m2)	>700	450-700	300-450	<300

How to Evaluate Options: A Decision Framework

Step 1: Establish the Baseline

Before evaluating reduction strategies, teams must quantify the embodied carbon of their reference design. This requires conducting a whole-building LCA using tools like One Click LCA, Tally, or the EC3 (Embodied Carbon in Construction Calculator) tool developed by Building Transparency. The Carbon Leadership Forum's benchmark database provides regional reference values for comparison. Teams should focus on lifecycle stages A1-A3 (material production) and A4-A5 (transport and construction) as the minimum scope, since these stages typically represent 80-90% of upfront embodied carbon.

Step 2: Target the Big Four Materials

Concrete, steel, aluminum, and insulation materials account for 60-80% of a typical building's embodied carbon. Prioritizing low-carbon alternatives for these four categories delivers the greatest impact per unit of effort. Low-carbon concrete using supplementary cementite materials (slag, fly ash, calcined clay) can reduce concrete's carbon intensity by 30-50% without performance compromise. Structural steel with high recycled content (electric arc furnace production) can achieve 40-60% lower emissions than basic oxygen furnace steel. Mass timber substitution for structural systems in appropriate building types can reduce structural embodied carbon by 40-75%.

Step 3: Require Product-Specific EPDs

Generic or industry-average data masks the significant variation between manufacturers. For Portland cement alone, the carbon intensity ranges from 650 to 1,050 kgCO2e per tonne depending on the production facility, fuel mix, and clinker ratio. Requiring product-specific, third-party verified EPDs during procurement enables genuine differentiation between suppliers and drives market signals toward lower-carbon producers.

Step 4: Integrate Early in Design

Embodied carbon reductions are most achievable during schematic and early design phases when structural systems, material specifications, and building geometry remain flexible. Research from the Structural Engineering Institute shows that structural optimization alone (right-sizing members, optimizing grid spacing, using efficient floor systems) can reduce structural embodied carbon by 10-20% at no additional cost. Once design development is complete, opportunities narrow dramatically.

Real-World Examples

Microsoft Silicon Valley Campus

Microsoft's new Silicon Valley campus, completed in 2024, achieved a 30% reduction in embodied carbon compared to its baseline design. The project team used One Click LCA throughout schematic design to compare structural systems and specified low-carbon concrete with 50% cement replacement. Cross-laminated timber was used for the office floor plates, displacing approximately 3,800 tonnes of CO2 equivalent that would have been emitted by a conventional steel and concrete structure. The project contributed EPD data for all major materials to the EC3 database, supporting industry transparency.

Skanska and the SE 2050 Commitment Program

Skanska, one of the world's largest construction companies, has committed to measuring and reporting embodied carbon on all projects through the Structural Engineers 2050 Commitment Program. By 2025, Skanska had completed whole-building LCA on over 200 projects across North America, building an internal benchmark database that enables data-driven material selection. Their project teams have documented average embodied carbon reductions of 15-25% through systematic material substitution and structural optimization, with top-performing projects achieving 40% reductions against industry baselines.

City of Vancouver Embodied Carbon Policy

Vancouver became one of the first North American cities to implement mandatory embodied carbon reporting and reduction requirements. Effective from 2025, all new buildings over 2,000 square meters must submit whole-life carbon assessments and demonstrate reductions against a declining benchmark. Early compliance data from the first year shows that participating projects achieved an average 18% reduction in upfront embodied carbon, with mass timber projects consistently performing 35-45% below the benchmark. The policy has driven a measurable increase in EPD availability from regional concrete and steel suppliers, with EPD coverage rising from 30% to over 70% of regional production capacity.

Action Checklist

• Conduct a whole-building LCA on at least one current project using One Click LCA, Tally, or the EC3 tool to establish a baseline
• Require product-specific EPDs for all structural concrete, steel, and insulation materials in procurement specifications
• Set embodied carbon reduction targets of at least 20% below regional benchmarks for new construction projects
• Integrate embodied carbon analysis into design review gates at schematic design and design development milestones
• Prioritize the "Big Four" materials (concrete, steel, aluminum, insulation) for low-carbon substitution efforts
• Evaluate mass timber or hybrid structural systems for building types under 12 stories where code and insurance conditions allow
• Track and report embodied carbon metrics through GRESB, CRREM, or internal ESG reporting frameworks
• Engage structural engineers early in design to optimize member sizes, grid spacing, and floor systems for material efficiency

FAQ

Q: How does embodied carbon differ from operational carbon? A: Operational carbon comes from the energy used to heat, cool, light, and power a building during its use phase. Embodied carbon covers the emissions from manufacturing materials, transporting them, constructing the building, maintaining it, and eventually demolishing it. The critical distinction is timing: operational carbon accumulates over decades and can be reduced through retrofits and clean energy, while embodied carbon is largely fixed at the point of construction. For a new, energy-efficient building, embodied carbon can represent 45-65% of the total lifecycle emissions.

Q: Is embodied carbon reduction expensive? A: Not necessarily. Research from the Carbon Leadership Forum and the World Green Building Council shows that 20-30% reductions in embodied carbon are achievable at zero to minimal cost premium (typically 0-2% of total construction cost) through material substitution and structural optimization. Deeper reductions of 30-50% may carry cost premiums of 2-5%, though these are declining as low-carbon material supply scales. Some strategies, like structural optimization and right-sizing members, actually reduce costs while lowering embodied carbon.

Q: What tools should I use to measure embodied carbon? A: The three most widely used tools in North America are One Click LCA (comprehensive, integrates with BIM software), Tally (Revit plugin for early design integration), and the EC3 tool from Building Transparency (free, open-access material comparison database). For Canadian projects, the Athena Impact Estimator for Buildings provides region-specific data. All require product-level EPD data for accuracy. Start with EC3 for material benchmarking, then use One Click LCA or Tally for whole-building assessments.

Q: Which lifecycle stages should I prioritize? A: Focus first on stages A1-A3 (raw material supply, transport to manufacturer, and manufacturing), which typically represent 70-85% of upfront embodied carbon. Stages A4-A5 (transport to site and construction) add another 5-15%. Use stage replacements (B4-B5) are significant for materials with shorter service lives, such as facades and MEP systems. End-of-life stages (C1-C4) and Module D (reuse and recycling potential) are increasingly important for circular economy assessments but remain secondary to production-stage emissions for initial reduction efforts.

Q: How do regulations differ across North America? A: The regulatory landscape is fragmented but accelerating. At the federal level, the US Buy Clean Initiative requires EPDs for steel, concrete, asphalt, and flat glass on federally funded projects. California's Buy Clean Act sets maximum GWP limits for state-funded projects. Colorado, Oregon, and Maryland have enacted or proposed similar legislation. New York City requires EPDs for city capital projects through Local Law 154. In Canada, the federal Green Procurement Policy sets embodied carbon requirements for government buildings, while British Columbia and Ontario have provincial requirements. The direction of travel is clear: mandatory reporting and reduction requirements will expand to cover private-sector construction within the next five to seven years.

Sources

• United Nations Environment Programme. (2024). 2024 Global Status Report for Buildings and Construction. Nairobi: UNEP.
• Carbon Leadership Forum. (2025). Embodied Carbon Benchmark Database: 2025 Update. Seattle: University of Washington.
• World Green Building Council. (2024). Bringing Embodied Carbon Upfront: Coordinated Action for the Building and Construction Sector. London: WorldGBC.
• Building Transparency. (2025). EC3 Tool: Embodied Carbon in Construction Calculator Documentation and Methodology. Seattle: Building Transparency.
• European Commission. (2024). Directive on the Energy Performance of Buildings (Recast): Whole-Life Carbon Requirements. Brussels: Official Journal of the European Union.
• Structural Engineering Institute. (2025). SE 2050 Commitment Program: Embodied Carbon Reduction Progress Report. Reston, VA: ASCE.
• Architecture 2030. (2024). Carbon Smart Materials Palette: Low-Carbon Alternatives for the Built Environment. Santa Fe, NM: Architecture 2030.