As we move into the second quarter of 2025, Mike Bentham reflects on the built environment’s progress to manage carbon emissions and meet the UK’s net-zero target.
In my experience of supporting clients targeting full alignment against industry-leading standards (eg, PAS 2080:2023), some fall short initially because of their sole focus on upfront carbon emissions – those associated with the initial construction of a project.
However, in the last 12 months there has been a welcome increase in the uptake of whole-life carbon as a concept, with some evidence of industry action.
For instance, in April 2024, a survey published by RLB showed that clients asked 33% of participating contractors to provide a whole-life carbon assessment (WLCA), up from 14% in the previous year.
A plethora of tools
Tools and guidance for delivering WLCA have become readily available, with the list of options growing weekly, including numerous contractors and consultants developing their own tools.
Some examples include the RICS Whole Life Carbon Assessment (v2), BCIS Built Environment Carbon Database (BECD) and the pilot UK Net Zero Carbon Building Standard.
However, as this plethora of choice continues, we need to strive for consistency in the use of tools to feed results into the shared benchmarking databases, such as BCIS BECD. If this doesn’t happen, benchmarking data and capability will vary company to company rather than defining a standard, which could lead to even more confusion within the industry.
Although many of the tools align, I would recommend we all work from one leading methodology like the RICS v2 in the UK, which is recognised in the UK Net Zero Buildings Standard.
Part Z: proposed steps for legislative action
There’s no doubt that the industry is united in its agreement on the need to consistently report and reduce carbon outputs.
Last October, I joined a roundtable discussion in Birmingham, hosted by Constructing Excellence Midlands, and one area that was unanimous around the table was that Part Z would drive the industry in the right direction.
Part Z is a proposed amendment to building regulations which would require developers to report on and reduce whole-life embodied carbon in projects.
Within six months of the new Labour government taking office, the following steps from the proposed Part Z were confirmed:
- By 2026, mandate the measurement and reporting of whole-life carbon emissions for all projects with a GIA of >1,000 sq m or that create more than 10 dwellings.
- By 2028, introduce legal limits on the upfront embodied carbon emissions of such projects, with a view for future revision and tightening as required.
Whole-life carbon assessment best practice
One example of where we are seeing good practice happening is in the US, where the RLB team has been working with our American colleagues to provide cost management and sustainability services to deliver whole-life embodied carbon analysis and consultancy for the redevelopment of a convention centre.
Once complete, it will be the first zero-carbon-certified convention centre in the world. We are not only applying the RICS v2 methodology, but developing digital solutions to analyse both whole-life carbon and whole-life cost in parallel to inform future design decisions.
To date, our team has completed a baseline whole-life embodied carbon assessment based on the concept design of the scheme; completed optioneering for opportunities to reduce embodied carbon; and completed a predemolition audit to identify and inform circular economy opportunities during the deconstruction of the existing convention centre.
Challenges in whole-life carbon management
Despite this encouraging progress, the industry still has a long way to go to effectively manage whole-life carbon emissions.
One challenge is the lack of government-led incentives and policy uncertainty, which is creating unwanted hesitancy in the uptake of WLCA. Without legal mandates, there is market caution to invest in innovative, low-carbon alternatives for key construction materials. If this continues, the industry risks losing momentum (and enthusiasm!) in its push for decarbonisation.
Part of this problem lies across the supply chain. Suppliers are nervous over the initial burden of investing in the development of low-carbon alternatives, despite increasing evidence showing savings on associated energy costs over time. This perspective, however, is highly dependent on which time frame (or in WLCA terms, ‘reference study period’) is being referred to when analysing comparisons of cost v carbon.
Long-term value over short-termism
Although we have progressed in terms of consistent standards and tools for WLCA, without legislative drivers mandating their implementation, the built environment will continue to lag what is needed to support the UK’s goal to become net zero by 2050.
There is also a dichotomy of the reference study period against the period of financial assessment. For example, the RICS WLCA standard requires that the following reference study period is applied, depending on the category of construction project:
- 60 years for domestic and non-domestic projects buildings;
- 120 years for infrastructure assets/civil engineering works (excluding mines, quarries and offshore structure related to resource extraction);
- Standalone fitout or enabling/temporary works: 20 and 60 years with reasonable replacement, repair and maintenance.
However, many organisations’ cost forecasting only takes into account data from shorter periods of five to 10 years, and remains tied to the performance of key financial decision-makers. The forecasts do not therefore align with the RICS reference study period time frames.
As 2025 continues, my advice to clients and the industry as a whole is to action, not just think: let’s move forward, regardless of whether we are mandated to do so. Put long-term value at the core, rather than short-termism.
Whole-life carbon analysis is imperative to identify and prioritise opportunities for innovation in materials and construction methods and build towards a real sustainable future.
Mike Bentham is an associate at RLB’s sustainability consultancy team.
