Progress in Reducing Emissions – But What about Timing?

We have been reflecting on our portfolio of CO₂ assessments and the general industry trajectory over the last couple of years, and found that:

• There is anecdotal evidence that embodied CO₂e is lower today vs 2-3 years ago for new projects;
• There has been a reduction in regulated operational CO₂ performance because of new Building Regulations and enhanced planning requirements;
• The supply chain has ramped up engagement as highlighted by the release of many EPDs, business decisions to help improvements, and the introduction of various standards.

This positive trajectory has steered new projects to a greater appreciation of both embodied and operational emissions.

Nonetheless, CO₂ accounting for buildings remains fragmented. Frontloading emissions during the procurement/construction stage (embodied) and focusing reductions through energy efficient and low carbon services remains common, an advantage enhanced by projections for future grid decarbonisation. A low carbon project is still delivered with this approach, but emissions are not equally spread out through the project lifecycle and there is an expectation on future decarbonisation mitigating upfront emissions.

A recent report from Arup reviews several academic models arguing that emissions should be weighted on when they are emitted. This is on the basis that avoided or delayed emissions today are more valuable than those reduced in the future. This provides a new layer of consideration in comparing operational and embodied emissions alongside the payback.

RICS, the organisation that develops the LCA methodology, introduced requirements on considering decarbonisation scenarios in their 2024 guidance update. The GLA question the reliability of the proposed factors given the general uncertainty of how decarbonisation should be considered. As a result, they do not permit their use in assessments.

The timing of emissions is a complex topic and leans on judgment as much as science. It is therefore understandable why authorities such as the GLA prefer to assess all forms of carbon emissions as if they were emitted on day one of a project. It promotes straightforward benchmarking and comparisons between projects. Perhaps, therefore, the best approach remains to ensure a balanced consideration of CO₂ emissions across a project lifecycle, with embodied considered as important as operational emissions.