Introduction
Embodied carbon from the construction and refurbishment of buildings is directly responsible for around 20 percent of built environment emissions in the UK1 and based on current figures, is likely to form over half of built environment emissions by 2035. There seems to be a growing degree of recognition within the industry that in order to meet its 2050 net-zero emissions target, the UK government must implement specific legislation to measure and limit embodied carbon and must do so quickly.
What is embodied carbon?
Embodied carbon is the amount of carbon emitted during the construction of a building or other infrastructure asset. It includes all emissions from the extraction of raw materials, the manufacturing and refinement of materials, transportation, installation and disposal of the building at the end of its lifetime. This is in contrast to operational carbon emissions, which are generated once an asset is in use.
Current regulation
Much of the recent existing regulation in the UK has focused on reducing operational carbon emissions through improved energy and heat efficiency in newly built and refurbished assets. In June 2022, the UK government updated the Building Regulations2 so that all new residential buildings and non-residential buildings are now required to deliver emissions savings of 31 percent and 27 percent respectively. Such changes were implemented in advance of the Future Homes and Future Building Standard (due to come into effect in 2025) which is aimed at reducing the operational carbon emissions produced by new homes by 75-80 percent, compared to current standards.
In contrast to the increasing regulation of operational carbon emissions of buildings, there is currently no statutory regulation of embodied emissions in the UK and many consider that the reduction of embodied carbon should be given the same strategic priority as the reduction of operational carbon emissions.
In 2021, the government published the UK Net Zero Strategy, which, amongst other targets, sets out the government's ambitions to help the construction sector improve reporting on embodied carbon with a view to exploring a maximum level for new buildings. This was followed in May 2022 by a report produced by the Environment Audit Committee (EAC) which suggested that the: "single most significant policy" that the government could introduce to reduce carbon emissions in the built environment would be to impose a mandatory requirement (incorporated into the building regulations and planning system) for whole life carbon assessments of buildings. In response to the EAC report, the UK government has announced that it intends to launch a consultation in 2023 in order "to mainstream the measurement and reduction of embodied carbon in the built environment." Whilst the EAC considers this to be "promising," many feel that the rate of change is not quick enough.
In the interim, the measurement and mitigation of embodied carbon in the building sector therefore remains voluntary. There are various a number of industry initiatives that are driving behavioral change, including the UK Net Zero Carbon Buildings Standard, which sets out the maximum level of embodied carbon that must not be exceeded in order to assess what constitutes a net-zero building. Various technical standards and methodologies have also been developed to measure a building's embodied carbon footprint, such as the RICS Whole Life Carbon Assessment for the Built Environment and the RIBA Guidance on Embodied and Whole Life Carbon Assessment for Architects.
In January 2023, the home building sector (through the Future Homes Hub) published an Embodied and Whole Life Carbon Implementation Plan, aimed at preparing the housing sector for mainstream measurement of embodied carbon for home builders. It envisages the development of a simple measurement method (with consistent defaults and assumptions) for measuring embodied carbon, along with various benchmarks and performance targets. This supplements existing initiatives, such as the targets for embodied carbon developed by RIBA as part of its 2030 Climate Challenge and the UKGBC's Net Zero Whole Life Carbon Roadmap for the UK Built Environment. There are also industry-driven proposed amendments to the Building Regulations 2010 (Part Z and Approved Document Z) that require the assessment of whole life carbon emissions and the limiting of embodied carbon emissions for all major building projects.
Whilst it is evident that many industry stakeholders have been actively seeking to optimize the embodied carbon footprint of new projects, this is far from mainstream practice across the sector. New legislation which standardizes the methods of assessment and reporting of embodied carbon is expected. This will no doubt play a critical role in reducing the built environment's significant contribution to the UK's carbon footprint and help deliver the country's commitment to achieve a 68 percent reduction in the UK's carbon emissions by 2030
Recommended links:
- Updated Building Regulations (June 2022): https://www.gov.uk/guidance/approved-document-b-2022-update
- Changes to Part L and Part F of the Building Regulations): https://www.gov.uk/government/consultations/the-future-homes-standard-changes-to-part-l-and-part-f-of-the-building-regulations-for-new-dwellings
- Environment Audit Committee (EAC) report May 2022: https://committees.parliament.uk/publications/30124/documents/174271/default/
- UK government response to EAC report: https://publications.parliament.uk/pa/cm5803/cmselect/cmenvaud/643/report.html
- UK Net Zero Carbon Buildings Standard https://www.nzcbuildings.co.uk/
- RICS Whole Life Carbon Assessment for the Built Environment: https://www.rics.org/globalassets/rics-website/media/news/whole-life-carbon-assessment-for-the--built-environment-november-2017.pdf
- RIBA guidance on Embodied and Whole Life Carbon Assessment for Architects: file:///C:/Users/aarm/Downloads/11241WholeLifeCarbonGuidancev7pdf%20(2).pdf
- Whole Life Carbon Implementation Plan (January 2023): https://www.futurehomes.org.uk/embodied-and-whole-life-carbon
- RIBA 2030 Climate Challenge: file:///C:/Users/aarm/Downloads/RIBA-2030-Climate-Challenge%20(1).pdf
- UKGBC's Net Zero Whole Life Carbon Roadmap for the UK Built Environment: https://www.ukgbc.org/ukgbc-work/net-zero-whole-life-roadmap-for-the-built-environment/
- Draft Building Regulations (Part Z and Approved Document Z): https://part-z.uk/proposal
Footnotes
1. According to UK Green Building Council
2. The updated regulations include amendments to Approved Documents Part F (Ventilation), Part L (Conservation of fuel and power) and the release of a new Approved Document for Overheating (Part O).
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