Carbon Budgets for Buildings - the need to measure embodied carbon in construction

With the world’s attention on carbon reduction at COP26, it can only be a matter of time before the construction industry has to seriously address the issue of embodied carbon in construction. As well as designers, perhaps the quantity surveyor might also have a very important role to play.

We have all become very familiar with working to increase the energy efficiency of our buildings. That together with a renewable source being a larger proportion of the energy that supplies properties, mean that the carbon used in operating our properties continues to decrease. As an industry, we might be confident that we can design and construct buildings that are consumption carbon neutral. Occasionally planning requirements and increasingly building regulations has made, even those whose environmental interest isn’t a priority, reduce operational carbon environmental impacts. However, there is currently no strong incentive to reduce the embodied carbon in construction.

Environmentalists are fully aware of the carbon budget for the planet necessary to limit global temperature change; world leaders need to understand their national carbon budgets required to promise net-zero targets; but developers, clients and design teams do not need to consider the carbon budget for constructing a building. An estimated 11% of the worlds annual carbon emissions come from new construction. So, for the sake of our future generations, we are going to need to start to take it seriously.

International climate finance advisor, Soren Lutken has called for cities to include a carbon budget in planning permits/permissions and it is clearly on some of our own politicians' agendas. North Norfolk MP, Duncan Baker, has raised the question of regulated embodied carbon in Parliament and as a member of the Environmental Audit Committee continues to work to increase governments understanding of the significant part that embodied construction plays in an approach to decarbonisation. ??

It can only be a matter of time before a carbon budget for a building, at the very least, becomes a target benchmark but more likely legislation.

To reduce embodied carbon in a proposed building project and design to a carbon budget, the design team can take a combination of three approaches:

1. Increase material efficiency – using designs that require less amounts of material per m2 of building including considering refurbishment rather than a new build.

2. Material choice – specifying materials considering the source including its locality and supply chain; modern methods of construction and fair-face alternatives

3. High carbon material substitution – considering lower carbon alternatives to steel, concrete and glass. ?

The success of this approach can be measured against the proposed carbon budget during design, allowing for improvements to be made and at completion for benchmarking or compliance checking.

Four years ago this week, the RICS produced a professional statement, Whole Life Carbon Assessment for the Built Environment. This provides a methodology of how levels of carbon in a building's design might be assessed, with quantities of materials measured in elemental cost planning groups, defined sources for carbon data and agreed units of measurement. Measurement and data, comforting words for any quantity surveyor and their estimating, analytical, monitoring and reporting skills can surely play an integral part in estimating and monitoring a buildings carbon budget.