Whole life carbon assessments are an increasingly common feature of UK construction projects. This is especially true in London, where the Greater London Authority requires such assessments for certain projects. Other local planning authorities will start to require similar.d
However, it is also increasingly common to see whole life carbon assessments used to justify new-build construction over retrofit, and vice versa. Despite all parties sharing a desire to reduce the amount of carbon that construction is responsible for, there is little consensus about when an assessment represents a genuine picture of a project.
This lack of maturity in the assessment process risks undermining confidence in whole life carbon measurement. There simply isn’t enough historical data to help build a clear picture. The industry therefore needs more whole life carbon assessments to be done, more often, in order to identify what approaches work best in the majority of situations. The answer will always be slightly different for every building, but establishing best practice is critical.
Currently, embodied carbon is not a feature of Building Regulations. In 2021, a group of industry experts published their proposal for ‘Proposed Document Z’ – an addition to the existing Building Regulations that would require whole life carbon emissions to be assessed and reported.
Furthermore, it would set a requirement for ‘carbon intensity’, with the aim of achieving more efficient resource use.
The document is a proof of concept, designed to show that embodied carbon could be integrated into the existing regulatory framework and help to accelerate the action that has already started in this area. Legislation is frequently cited as a key driver in shifting attitudes and behaviour.
The proposal would not immediately set limits on carbon. It has been designed to start with measuring, assessing and reporting, to encourage action. Once action is commonplace, specific targets are easier to implement.
Regulated whole life carbon targets, and their phased introduction as suggested by Proposed Document Z, would make sustainable design and construction more consistent across the built environment.
At the moment, taking voluntary action to reduce embodied carbon is effectively penalised on many projects, as it tends to cost more to do compared to not taking such action. Legislation changes will come eventually, but that shouldn’t discourage anyone from looking at whole life carbon now.
Issues around consistency of assessment and lack of regulation make it hard to identify an obvious first step towards lowering whole life carbon. Even when such a step is taken, progress can soon stall afterwards.
As such, it’s important to remember that the entire construction industry cannot change how it operates overnight. Immediate small changes are the best approach and can quickly start to make big impacts.
On an individual level, choosing to address whole life carbon and engage with the assessment process on a live project is an important first step. It’s impossible to reduce the environmental impact of every single product and component on one project. Attempting too much change in one go is overwhelming, and potentially counterproductive.
Instead, tackling whole life carbon is a process of learning through action; of understanding what works and what doesn’t and applying the lessons from one project to the next.
The construction industry has embarked on that journey with operational carbon. Now, it needs to go through the same process with embodied carbon, in order to deliver low whole life carbon projects consistently. The principal difference is the urgency of the climate emergency, which means going on this particular journey faster than we might otherwise have done.
In operational carbon terms, a building’s performance is affected by its occupants. An ‘efficient’ building can be operated relatively inefficiently, and vice versa.
Embodied carbon is not subject to the same potential variation. It can’t be affected by occupant behaviour. Whether the embodied carbon is lower or not is entirely down to the design and specification decisions that are made.
Looking at all the different life cycle stages where carbon can be accounted for, it might feel daunting to wonder how to address each one. However, there is a clear and obvious starting point.
About 50% of all embodied carbon is in the extraction of raw materials and the manufacture of construction products. Big step changes therefore come from selecting different materials.
Smaller individual steps have the power to deliver substantial reductions in embodied carbon. Once bigger changes are also introduced at the project level, the knowledge of how to do them cannot be ‘unlearned’ – meaning the lesson is carried over onto future projects.
It is said that the best time to plant a tree was thirty years ago, and the next best time is now. In an ideal world, the construction industry would have begun lowering embodied carbon and resource use thirty years ago. To deliver buildings fit for the low carbon future we are all striving for, the next best time to address it is now.
The expert team at Darren Evans is here to support you in doing just that.
We are dedicated to making a difference and to supporting you in achieving your low carbon goals towards net zero. As market leaders in whole life carbon, we have a track record of reducing embodied carbon and operational carbon, and assessing whole life carbon on construction projects.
Companies and organisations across the construction industry work with us to meet their sustainability targets, including major contractors like Bouygues UK. Thanks to our experience, we can tailor our work to suit your needs.
To find out more about working with us, view the full range of our services, or contact us to discuss your project.
