Data Analysis · Built Environment · Embodied Carbon

The Carbon Hidden in Construction

How material choices shape a building's lifetime footprint — and what it means for EU Taxonomy eligibility

Most decarbonisation attention in real estate focuses on operational energy — heating, cooling, electricity. But the carbon locked into a building's structure before a single tenant moves in is growing in regulatory and financial significance. This analysis quantifies embodied carbon across key construction materials, models the impact of low-carbon material specification on a 5,000 m² mixed-use building, and connects those decisions to EU Taxonomy disclosure requirements now shaping capital allocation across Europe.

Building type: Mixed-use, 5,000 m² Materials covered: Cement, Steel, Insulation, Timber Framework: EU Taxonomy (Activity 7.1) · EN 15978 lifecycle stages Sources: ICE DB v4.1 · WorldGBC 2019 · RICS 2017 · EU Taxonomy Delegated Act
Purpose of this Analysis

Why Material Selection Is Now a Business Decision

Embodied carbon — the emissions associated with producing, transporting, and assembling construction materials — has historically been treated as a technical concern for engineers, not a strategic one for developers or investors. That is changing rapidly.

The EU Taxonomy for Sustainable Activities (Activity 7.1 — Construction of new buildings) now requires that for buildings larger than 5,000 m², the lifecycle Global Warming Potential must be calculated for each stage and disclosed to investors and clients on demand. This makes embodied carbon a disclosure obligation, not just a design consideration.

This analysis was designed to answer a practical question: how much does material specification actually move the needle on a building's embodied carbon, and what is the financial and regulatory consequence of that difference?

Key Learnings

What the Analysis Shows

1

Embodied carbon will be half of all new construction emissions by 2050. As operational carbon falls through energy efficiency and grid decarbonisation, embodied carbon becomes the dominant challenge in the building lifecycle — yet most current project assessments still focus primarily on operational performance.

2

Low-carbon material alternatives can reduce embodied carbon by 40–65% per material. Switching from standard Portland cement to a GGBS blend, or from virgin to recycled steel, delivers large reductions with no change in structural performance — decisions that are available today, at project design stage.

3

At project level, the difference is over 1,000 tCO₂e on a single building. For a 5,000 m² mixed-use development, low-carbon material specification reduces total embodied carbon by approximately 45% — a figure that now has direct regulatory and investor disclosure implications under the EU Taxonomy.

Analysis 1 · Lifecycle Context

Embodied Carbon Is Growing in Importance — Not Shrinking

Buildings account for 39% of global carbon emissions. Of this, 28% comes from operational carbon (energy used in heating, cooling, lighting) and 11% from embodied carbon (materials and construction). But this picture is shifting. As grids decarbonise and energy efficiency standards tighten, operational emissions will fall — making embodied carbon proportionally more significant. By 2050, upfront carbon from materials and construction is projected to account for approximately half of all emissions from new buildings globally.

Embodied vs operational carbon split today and projected to 2050
Analytical observation: The shift from a 28/11 split today to a near 50/50 split by 2050 reflects a structural change in where decarbonisation effort is needed — not a change in what buildings emit. Companies and developers that continue to focus exclusively on operational performance are preparing for a challenge that is becoming less significant, while ignoring the one that is growing.
Analysis 2 · Material-Level Carbon Factors

The Carbon Gap Between Conventional and Low-Carbon Materials

The four material categories shown here — cement/concrete, structural steel, insulation, and timber — represent the largest contributors to embodied carbon in mixed-use construction. For each, a conventional specification and a low-carbon alternative are compared using published carbon factors. In every case, the low-carbon alternative is available today, requires no novel technology, and delivers the same structural or functional performance. The difference lies in material specification decisions made at the design stage — typically before a shovel enters the ground.

Embodied carbon coefficients by material: conventional vs low-carbon alternatives
Analytical observation: The largest single reduction available is in structural steel — switching from virgin (blast furnace) to recycled content (electric arc furnace) steel cuts the carbon factor from 1.72 to 0.73 kgCO₂e/kg, a 58% reduction. Cement offers a 40% reduction through blended GGBS formulations. These are not experimental solutions — they are commercially available specifications that forward-looking developers are already using. The question is not whether low-carbon materials exist, but whether they are being specified.
Analysis 3 · Project-Level Impact

1,003 tCO₂e — The Carbon Cost of Conventional Specification on One Building

This chart translates material-level carbon factors into project-level consequences for a 5,000 m² mixed-use building — the exact threshold at which EU Taxonomy Activity 7.1 requires lifecycle Global Warming Potential to be calculated and disclosed. Material quantities per m² are based on RICS and industry benchmarks for mid-rise mixed-use construction. The comparison shows the total embodied carbon for each material category under conventional versus low-carbon specification, and the cumulative difference across the whole building.

Project-level embodied carbon comparison: 5,000m² mixed-use building, conventional vs low-carbon materials
Analytical observation: The total embodied carbon under conventional specification is approximately 2,252 tCO₂e. Low-carbon specification reduces this to 1,249 tCO₂e — a saving of 1,003 tCO₂e (45%) without changing the building's function, size, or structural integrity. Concrete and cement dominate the total because of the large volumes used. This is why cement specification — specifically the clinker-to-GGBS ratio — is the single highest-impact material decision on most construction projects.
What This Means for the Industry

From Design Decision to Business Consequence

The 1,003 tCO₂e difference between conventional and low-carbon specification on a single 5,000 m² building is no longer just an environmental metric. Under the EU Taxonomy, it is a disclosure obligation. Under green finance frameworks, it is a condition of access to preferential lending. And as CSRD Scope 3 reporting expands, it will increasingly appear in the sustainability disclosures of every company that commissions, owns, or finances construction. Three groups are most directly affected.

01
Developers & project teams
Material specification decisions made at design stage — typically 12–18 months before completion — determine the building's lifecycle GWP disclosure figure. Under EU Taxonomy Activity 7.1, buildings over 5,000 m² must calculate and disclose this figure to investors on demand. Developers who cannot demonstrate a lifecycle assessment are not Taxonomy-eligible, which affects access to green bonds and sustainable finance instruments.
02
Real estate investors & asset managers
Investors financing new construction are increasingly required to report the Taxonomy alignment of their portfolios. A building without a lifecycle GWP calculation cannot be reported as a Taxonomy-aligned investment. As SFDR and CSRD requirements tighten, the embodied carbon profile of a building — determined largely by its material specification — becomes a due diligence item, not just a sustainability preference.
03
Sustainability consultants & advisors
The gap between conventional and low-carbon specification — 45% on a single building — is achievable using existing materials and today's supply chains. The advisory opportunity lies in helping developers understand this gap early enough to act on it: at concept design stage, not at practical completion. Once concrete is poured, nothing can be done about its upfront carbon. The value of embodied carbon advisory is highest before construction begins.
Bottom line: Material selection is no longer a purely technical decision. For any mixed-use building above 5,000 m², it is a regulatory disclosure requirement, a green finance eligibility condition, and an increasingly visible metric in investor reporting. The embodied carbon saved through low-carbon specification — over 1,000 tCO₂e on a single building — is the kind of number that appears in Taxonomy disclosures, sustainability reports, and green bond frameworks. Developers and advisors who build the capability to quantify and act on this difference early are better positioned than those who treat it as a compliance exercise at the end of a project.
Methodology

Data & Approach

Carbon Factors — Cement & Steel

Embodied carbon coefficients for cement and steel are sourced from the ICE Database v4.1 (Circular Ecology / University of Bath, October 2025). CEM I Portland cement: 0.84 kgCO₂e/kg. CEM III/A (50% GGBS): 0.50 kgCO₂e/kg. Virgin steel (worldsteel 2023 rebar benchmark): 1.72 kgCO₂e/kg. Recycled steel, European EAF average: 0.73 kgCO₂e/kg.

Carbon Factors — Insulation & Timber

Embodied carbon coefficients for insulation and timber are sourced from the RICS Whole Life Carbon Assessment for the Built Environment professional statement (2017). Mineral wool insulation: 1.28 kgCO₂e/kg. Wood fibre insulation: 0.47 kgCO₂e/kg. Structural timber: 0.46 kgCO₂e/kg. Cross-laminated timber (CLT): 0.31 kgCO₂e/kg. Biogenic carbon storage is excluded from these figures.

Project-Level Modelling

Material quantities for a 5,000 m² mixed-use building are based on published RICS and industry benchmarks for mid-rise mixed-use construction: concrete/cement at 400 kg/m², structural steel at 50 kg/m², insulation at 15 kg/m², and timber fit-out at 20 kg/m². Total embodied carbon is calculated as: quantity (kg/m²) × carbon factor (kgCO₂e/kg) × floor area (m²). Results are expressed in tonnes CO₂e.

EU Taxonomy Reference

The EU Taxonomy disclosure requirement cited in this analysis refers to Activity 7.1 (Construction of new buildings) of the EU Taxonomy Climate Delegated Act (EU 2021/2139). Point 3 of the Technical Screening Criteria states that for buildings larger than 5,000 m², the lifecycle Global Warming Potential must be calculated for each lifecycle stage and disclosed to investors and clients on demand. The acquisition and ownership criterion (Activity 7.7) references EPC class A or top 15% Primary Energy Demand as the alignment threshold.

Limitations

Material quantities are indicative benchmarks, not project-specific calculations. Actual quantities vary significantly by structural system, building height, and design. Carbon factors represent A1–A3 lifecycle stages (product stage) only and do not include transport to site (A4), construction process (A5), or end-of-life stages. A full lifecycle assessment under EN 15978 would be required for EU Taxonomy compliance purposes. This analysis is intended as a portfolio demonstration of embodied carbon methodology, not a compliance-grade assessment.