What is embodied carbon and why does it matter?

Embodied carbon covers the emissions linked to materials and construction, from extraction and manufacture through to end of life. It already accounts for around one in 10 tonnes of UK greenhouse gas emissions and will become more significant as operational energy use reduces.

Why is embodied carbon described as a ‘tenfold challenge’?

Current good practice buildings carry up to 10 times more embodied carbon than will be acceptable by 2050. Meeting future targets will require a fundamental shift in design, procurement and material choices rather than incremental change.

What role do targets play in reducing embodied carbon?

Clear, binding targets set from the outset of a project help turn carbon assessment into a design driver. They create focus across the design team and supply chain, shifting the conversation from measurement to meaningful reduction.

What approaches can help reduce embodied carbon in buildings?

Three key approaches are designing lean to reduce material use, using biogenic materials such as timber that store carbon, and embracing circularity through reuse and reclaimed materials. Together, these can deliver both environmental and commercial benefits.

Thought Leadership

Embodied carbon and the tenfold challenge

Min Read

by Joseph Smith

Architect, Architecture

Earlier this year, I began contributing to a research study run by the Centre for Construction Best Practice (CCBP), a Liverpool-based organisation examining the feasibility of mandating whole life carbon assessments across public sector construction.

The study has brought together professionals from organisations across the built environment. I’ve contributed to the study bringing live project experience and my work as one of the sustainability champions at AHR. The process has sharpened my understanding of where the industry stands on embodied carbon and how significant the challenge ahead really is.

I’m sharing these reflections because I think the scale of what lies ahead is still not widely enough understood. And because the window for making a difference is shorter than it might appear.

What embodied carbon actually means

When we talk about a building’s carbon impact, there are two sides to the story. Operational carbon is the energy used to heat, cool and power a building across its lifetime. Embodied carbon covers everything else, the emissions generated in extracting, manufacturing and transporting materials, those produced during construction on-site, and what happens at the end of a building’s life.

Real progress has been made on operational carbon in recent years, driven in part by the clear performance benefits it delivers. Lower energy demand means lower bills, reduced reliance on renewables and better thermal comfort. These are tangible outcomes that clients can feel and measure. Embodied carbon is a harder case to make, precisely because those direct benefits are less visible. Yet it accounts for one in every 10 tonnes of annual greenhouse gas emissions in the UK, more than the country’s aviation and shipping emissions combined¹, and as buildings become progressively more efficient in use, embodied carbon’s share of the total will only grow.

A good practice building built today carries 10 times the embodied carbon that will be acceptable in 2050. Not twice or three times. Ten times.

In the schools sector, where the Department for Education (DfE) has set a current target of 550 kgCO2e/m² upfront embodied carbon, the trajectory set out in the Net Zero Carbon Buildings Standard takes that figure to 55 kgCO2e/m² by 2050². A tenfold reduction in 25 years. No amount of incremental improvement will close a gap of that size. Something more fundamental has to change in how we approach design and procurement.

What the research revealed

The CCBP study is encouraging in many ways. The appetite for change across the industry is real, and there is real willingness to move further and faster. But the message was consistent. Without clear, binding targets embedded from the very start of a project, embodied carbon assessments will continue to function as a reporting tool rather than a design driver. Reporting for its own sake, without meaningful consequences, risks becoming a box to tick.

Mandated targets change behaviour. Through my experience, I have seen how a clear number galvanises an honest response. Contractors take it seriously, and so does the wider design team. The conversation shifts from ‘what is our number?’ to ‘how do we hit it?’. The ambiguity in the current policy trajectory is locking in supply chain inertia at exactly the moment when investment and innovation are most needed.

An insightful session bringing together industry experts

Three levers that matter

Based on my knowledge, three approaches are likely to have the greatest impact on reaching the 2050 targets:

Designing lean is the most direct route. Using less material from the very outset. This has to happen at concept stage. Once design decisions have been made and approvals are in place, the opportunity to fundamentally reduce material quantities has largely passed.
Biogenic carbon draws on materials that sequester carbon as they grow. Hackbridge Primary School³ is one of the most compelling low-carbon examples I’ve found. Using UK-grown C16 timber with bio-based insulation and carefully considered glazing ratios, it has achieved approximately half the tenfold reduction we’ll eventually need. That’s an achievement, but the curve keeps going down and the path to the second half is considerably harder.
Circularity offers a third approach. The Royal Institution of Chartered Surveyors (RICS) whole life carbon standard includes a D1 category for materials reclaimed at the end of a building’s life and reused in new construction, reducing the upfront carbon burden of what comes next. The most compelling examples I’ve come across are in the Netherlands. At Boschgard⁴, 84% of materials were sourced as secondary, delivering a 70% saving on CO2 emissions and reducing construction costs by a fifth. Lean and circular approaches are not just better for the environment; they can make strong commercial sense too.

Upfront carbon limit new works - schools

Data sources: ²³⁵

A supply chain problem that needs solving now

Of everything I’ve learnt, the timescale challenge around the supply chain concerns me most. New building products take five to 10 years to reach the market. A softwood tree takes 40 years to grow. The timber in a school completed in 2024 was planted in the 1980s.

If we’re to build with low-carbon UK-grown timber through the 2030s and 2040s, those trees need to be in the ground today. The choices being made now by designers, clients and policymakers are shaping what will be available in 2035, 2040 and 2050.

This is why clear, long-term targets matter so much. Supply chains don’t invest and innovate in response to ambiguity, they respond to sustained, predictable demand.

Where we go from here

I came away from this research more convinced than when I started that embodied carbon is approaching a tipping point. Momentum is building, regulatory direction is clear, and sector-level requirements are beginning to take shape.

The organisations that will have the greatest positive impact are those engaging with this now. Embedding whole life carbon thinking early in the design process, building capability in circular and biogenic approaches, and actively contributing to the industry conversations that will shape policy over the next decade.

At AHR, we’re committed to bringing embodied carbon thinking further forward in the work we do, and to staying closely connected with what’s happening across Europe as well as the UK.

If you’d like to discuss any of these ideas, I’d welcome the conversation

Frequently asked questions

: Embodied carbon covers the emissions linked to materials and construction, from extraction and manufacture through to end of life. It already accounts for around one in 10 tonnes of UK greenhouse gas emissions and will become more significant as operational energy use reduces.
: Current good practice buildings carry up to 10 times more embodied carbon than will be acceptable by 2050. Meeting future targets will require a fundamental shift in design, procurement and material choices rather than incremental change.
: Clear, binding targets set from the outset of a project help turn carbon assessment into a design driver. They create focus across the design team and supply chain, shifting the conversation from measurement to meaningful reduction.
: Three key approaches are designing lean to reduce material use, using biogenic materials such as timber that store carbon, and embracing circularity through reuse and reclaimed materials. Together, these can deliver both environmental and commercial benefits.