Counting carbon

The Environmental Audit Committee has called for a rapid reduction in greenhouse gas emissions, as well as operational carbon targets. Hywel Davies looks at the detail

The UK’s built environment is responsible for 25% of our greenhouse gas emissions. In 2021, the Environmental Audit Committee (EAC) launched an inquiry into the sustainability of the built environment, looking to understand the routes to net zero carbon for our future building needs. 

This included looking at low carbon materials and policies to minimise the whole-life carbon impact of new buildings. This in turn led to a focus on embodied carbon in buildings.

While current regulations require energy performance certificates for all buildings and display energy certificates for public buildings, which seek to quantify the operational carbon impact of the buildings, we currently have no similar requirements for those outside London to measure the impact of the carbon embodied in the fabric and systems that make up a building. 

With the government seeking the building of 300,000 new homes each year, there will be a significant volume of construction activity over the next decade. So there is an urgent need to measure embodied carbon in our buildings. 

The EAC ambitiously calls for a clear timeframe for the introduction of whole-life carbon assessment

The EAC report1 was published in May 2022 and the second chapter is devoted to embodied carbon. It sets out the case for mandatory whole-life carbon assessments, which would identify products with low embodied carbon, enabling constructors and developers to decide which low carbon materials and systems to use.

To reduce carbon emissions from construction, the committee recommends that the government introduces a mandatory requirement for whole-life carbon assessments for buildings. It proposes that this requirement should be incorporated into Building Regulations and the planning system. Such an assessment would calculate the emissions from the construction, maintenance and demolition of a building, and the energy used in its day-to-day operation. 

The current proposal is not to set targets or regulate the amount of embodied carbon, just to measure and declare it. As has already been indicated by the response to the industry proposals for a new part to the Building Regulations covering embodied carbon measurement, the ‘Part Z’ proposal which CIBSE supports, many in the construction industry are willing and able to undertake such assessments. 

There are already standards, a clear methodology and a framework around which to standardise reporting. The cost of carrying out assessments can be minimal if undertaken as part of the design process alongside energy performance calculations.

Other countries, such as the Netherlands and France, already require assessments and some UK local authorities are already asking for them too. Without a national approach, the UK risks slipping behind comparator countries in monitoring and controlling embodied carbon in construction. 

The committee is also clear that ‘if the UK continues to drag its feet on embodied carbon, it will not meet net zero or its carbon budgets.’ Once assessments are being done, then we will have the data to provide evidence-based targets for buildings to align with the UK’s net zero goals.

The EAC ambitiously calls for a clear timeframe for the introduction of
whole-life carbon assessments, government targets to be set by the end of 2022 at the latest, and for these to be introduced not later than December 2023.

It also identifies retrofit and reuse of buildings as a means to keep carbon locked in and argues for prioritising reuse over new build. While government policy is said to prioritise retrofit and reuse, the committee is concerned that reforms to permitted development rights appear to have created an incentive to demolition and to build new, rather than retrofit. 

The EAC has also identified a chronic skills gap in energy efficiency and retrofit and notes that, without these vital green skills in the UK economy, we will simply fail to achieve our net zero ambitions. As we look to develop our net zero carbon policy, the EAC has provided a timely call for government to tackle the challenge of embodied carbon. Journal readers will wish to watch.

1 Building to net zero, Environmental Audit Committee, House of Commons, May 2022,