Measuring Carbon Emissions in the Built Environment

Part of the Heritage Counts series. 4.5 minute read

How carbon is measured significantly impacts what climate change mitigation measures are seen to be most effective. It also has a significant impact on how the contribution of the built historic environment is perceived and estimated.

On this page
  1. What we measure
  2. What we don't measure
  3. Building consumption emissions into the predictions
  4. Implications on the UK's carbon targets

What we measure

The UK’s net zero targets are based on measurement of the UK’s territorial carbon emissions. Alternative measures of the UK's carbon footprint, such as consumption-based emissions, produce significantly larger footprints.

Consumption emissions better align with a whole-life carbon assessment for buildings and better capture the embodied emissions that significantly contribute to climate change. Generally, a focus on territorial emissions underestimates the crucial contribution the historic environment can provide to climate change mitigation.

Defining the types of emissions

The UK’s net zero target is based on measured carbon emissions within the UK’s borders, known as territorial emissions, which exclude all emissions emitted in international territory.  

Another measure of UK emissions known as production emissions measure emissions on a 'residents' basis, representing emissions caused by UK residents and industry, whether in the UK or abroad. They exclude emissions within the UK, which can be attributed to overseas residents and businesses. International aviation and shipping emissions are allocated to countries based on the operator of the vessels. 

Consumption emissions measure emissions produced in the UK, as well as emissions produced during the making and transporting of imported materials and components.

Source: Defra, 2020

What we don't measure

When we look at consumption emissions in the UK's, these are substantially higher than territorial emissions.

Trade expansion over recent decades has allowed higher-income countries to ‘off-shore’ the adverse impacts of their consumption on ecosystems and biodiversity, through trade in commodities, goods and services with lower income countries (Dasgupta, P., 2021).

  • Since 1996, territorial emissions declined by 48% while consumption emissions declined by 29% in the same period (Defra, 2020)
  • In 1996, the UK’s consumption emissions were only 5% higher than territorial emissions, but by 2020 consumption emissions were 43% higher than territorial emissions (Defra, 2020) 
  • These diverging trends are largely because the UK economy has moved from a manufacturing base to a service base, and with that now has a greater dependence upon imports and their associated embedded emissions (Defra, 2020)
  • According to the UKGBC, 30% of all construction emissions relate to non-territorial ‘consumption’ emissions, i.e., construction materials and products produced overseas and imported to the UK (Everingham, 2022). The figure below demonstrates the UK construction sector’s increasing reliance on imported materials and a growing trade deficit, where the value of imports exceeds the value of exports

Figure MCE 2 shows us that:

  • The trade deficit in construction materials was historically at its smallest throughout the 1990s, with a mean of £0.3 billion over this period (DBT, 2023)
  • This trade deficit was 24% of the value of imports in the 1990s compared to the latest data (Q4 2022), when the trade deficit stood at 73% (DBT, 2023)

Building consumption emissions into the predictions

The UKGBC 'Net Zero Whole Life Carbon Roadmap for the Built Environment' (2021) estimates the carbon footprint of the UK built environment, defined on a consumption basis (including emissions from imported construction products and materials).

The roadmap was planned to be consistent with wider UK carbon targets and budgets using the CCC 6th Carbon Budget as an overarching reference, with additional datasets and feedback provided by the CCC (UKGBC, 2021).

The evidence demonstrates:

  • The UK Built Environment is directly responsible for 25% of total UK greenhouse gas emissions (buildings and infrastructure)
  • If surface transport (vehicle emissions) is included within the scope of the built environment, the total share of UK emissions from the built environment increases to 42%
  • Embodied carbon emissions have reduced by almost 20% between 1990 and 2018
  • In the current trajectory, including embodied emissions, the sector will fall short of 2050 net zero targets, with only a 60% reduction achieved compared to 1990. This will leave 115 MtCO2e of residual emissions to offset

Implications on the UK's carbon targets

This evidence demonstrates the importance of the models and the data we use to inform climate policies and actions.

Failure to measure and count the whole life carbon of buildings means we underestimate the contribution of heritage and existing buildings more generally. The problem is shifted from one part of the building lifecycle to another, and we risk not meeting carbon targets (Historic England, 2019).

References

  1. Dasgupta, P. (2021). ‘The Economics of Biodiversity: The Dasgupta Review.’ Available at: https://www.gov.uk/government/publications/final-report-the-economics-of-biodiversity-the-dasgupta-review (Accessed: 05.09.23)
  2. Defra (2020). ‘Carbon footprint for the UK and England to 2020.’ GOV.UK. Available at: https://www.gov.uk/government/statistics/uks-carbon-footprint/carbon-footprint-for-the-uk-and-england-to-2019 (Accessed: 08.11.23)
  3. Department for Business and Trade (DBT) (2023). ‘Monthly Bulletin of Building Materials and Components No. 581.’ Available at: https://www.gov.uk/government/statistics/building-materials-and-components-statistics-july-2023 (Accessed: 12.07.23)
  4. Everingham, D (2022). ‘The Whole Life Carbon Roadmap – Answering your data FAQs received to date | UKGBC.’ Available at: https://ukgbc.org/news/the-whole-life-carbon-roadmap-answering-your-data-faqs-received-to-date/#:~:text=Furthermore%2C%20although%20a%20proportion%20of,and%20imported%20to%20the%20UK (Accessed: 8.11.23)
  5. Historic England (2019). ‘There’s no place like old homes- Re-use and Recycle to Reduce Carbon.’ Available at: https://historicengland.org.uk/content/heritage-counts/pub/2019/hc2019-re-use-recycle-to-reduce-carbon/ (Accessed: 12.07.2023)
  6. UKGBC (2021). ‘Net Zero Whole Life Carbon Roadmap.’ Available at: https://ukgbc.org/wp-content/uploads/2021/11/UKGBC-Whole-Life-Carbon-Roadmap-A-Pathway-to-Net-Zero.pdf (Accessed: 25.08.23)