Building with purpose: How low carbon construction shapes the future

When we talk about a building’s carbon footprint, the focus often falls on operational energy use, like heating, cooling, and lighting. But that’s only part of the picture. A significant share of emissions occurs long before the lights are switched on. Embodied carbon is the emissions tied to material production, transport, and construction, and can account for more than 50% of a building’s lifetime footprint.

This article explores what embodied carbon is, why material choices matter, and how upcoming regulations like the EU’s Carbon Border Adjustment Mechanism (CBAM) will influence project decisions.

What is embodied carbon?

Embodied carbon refers to the greenhouse gas emissions generated across the lifecycle of construction materials, from manufacturing and transportation to installation, maintenance, and end-of-life disposal. The figure below illustrates the different phases in a building’s lifecycle and where embodied emissions occur.

The largest share of embodied emissions happens before the building is operational, during the product and construction stages (A1–A5). These stages include material production, transport to site, and construction or installation. Often called upfront embodied emissions, these emissions represent the greatest opportunity for early intervention. Decisions made at this stage, such as selecting lower-carbon materials, can lock in long-term benefits and even influence future renovation or demolition impacts.

Later in the lifecycle, downstream emissions arise from maintenance and replacement during the use stage (B1–B5) and from end-of-life treatment and disposal (C1–C4). Operational emissions (B6–B7), which relate to energy and water use, remain important, but as buildings become more energy-efficient, embodied carbon increasingly dominates the overall footprint.

Why do material decisions matter?

Every material has its own carbon profile. Cement and steel, for example, are essential but traditionally carbon-intensive. However, specifying smarter alternatives can deliver major reductions without compromising performance or cost. High-recycled-content metals can significantly cut emissions from steel and aluminum, while cements with lower clinker content reduce manufacturing impacts. Real-world projects show that reductions of 20–40% in embodied carbon are achievable through early design decisions, such as optimizing structural specifications, prioritizing recycled content, and avoiding over-design. 

What does CBAM change for projects?

The EU’s Carbon Border Adjustment Mechanism (CBAM) is transforming carbon from a disclosure issue into a compliance and cost issue. Starting in 2026, CBAM will apply a carbon price, aligned with the EU ETS, to imported high-impact materials such as cement, iron and steel, and aluminum.

For construction projects, this means two things:

1. Low-carbon suppliers become the safer commercial choice. Their products will avoid CBAM-related cost penalties.
2. Procurement must be data-ready. Factory-specific Environmental Product Declarations (EPDs) will be essential for CBAM reporting and compliance.

In short, specifying low-carbon materials no longer means just being climate-smart, it’s being policy-ready. CBAM will make carbon-intensive imports more expensive, accelerating the shift toward lower-carbon alternatives and reducing upfront emissions in the building lifecycle.

How to address embodied carbon?

The most effective way to address embodied carbon is to start early, during the design phase. Building smart means being aware of the carbon impact of material choices from the outset. Initial decisions not only influence upfront emissions but also affect what happens at the end of a building’s life, including demolition and disposal. Conducting Life Cycle Assessments (LCAs) during material selection helps compare options and identify opportunities to substitute high-impact materials with lower-carbon alternatives that still meet performance, cost, and program requirements. This proactive approach ensures compliance with upcoming regulations such as CBAM and aligns with investor expectations for sustainable, future-proof assets.

How BDO can help

Our Climate & Decarbonization team supports you from the earliest stages of design. We perform LCAs to guide material choices and reduce embodied carbon effectively. In addition, we offer in-house expertise on CBAM and provide a full suite of related services, from ensuring basic compliance to developing strategies that add value and minimize financial impact. Whether you are planning a new build or a major refurbishment, we help you integrate low-carbon solutions without compromising cost or performance.