Carbon Challenge Needs Whole-life Views, Not Half-truths
31 Oct 2019
Published in: Construction News, October 2019
Against the backdrop of climate change, the construction industry needs to chart the roadmap to a net-zero-carbon society by 2050.
This requires an intelligent and informed industry discussion about embodied and operational carbon. Crucially, it now calls for a reinvigorated focus on the whole-life performance of buildings and assets.
"Clients need to have a far greater appreciation of the fact that buildings must last longer and may have multiple uses over their lifecycle"
The reality is that many projects are currently conceived without sufficient consideration of lifecycle carbon impacts. There is all too often a focus on short-term embodied carbon in building-material selection, rather than consideration of carbon emitted across the lifecycle of assets.
Whole-life thinking calls for a longer-term perspective. Specification decisions and carbon measurement must consider the operational performance of a building or structure, its flexibility to adapt to user needs and its recycling at the end of life, as well as the materials used to construct it.
While embedded carbon from manufacturing processes may be easier to calculate, it fails to address some critical factors that are of key importance when assessing the true environmental impact of buildings and infrastructure over their lifetime.
For example, a product with a higher embodied carbon footprint at the point of delivery could actually be three or four times more durable, more thermally efficient, or might require much less maintenance over its lifespan than an alternative with lower embodied carbon.
All these factors should be considered when assessing a whole-life carbon footprint.
London Plan leads the way
The next Government Construction Strategy and the new National Design Guide provide an excellent opportunity to establish a framework for improved whole-life thinking.
The latest draft of the London Plan now includes a requirement for both embodied and whole-life carbon to be calculated and reduced. London’s leadership on this should be captured in government strategy.
Firstly, this strategy must put material efficiency and building longevity at the heart of design. The longer a building’s lifespan, the more embodied emissions in building materials are spread out over time.
Ultimately, clients and investors need to have a far greater appreciation of the fact that buildings must last longer and may have multiple uses over their lifecycle.
They will need to accept that investment modelling may need to change. A building structure that enables reuse becomes a valuable, low-carbon resource for future development.
Secondly, we need to have a more informed and intelligent conversation about material specification, adopting responsibly sourced, sustainable supply chains and a greater focus on lifecycle carbon assessment (LCA).
LCA is an approach we support, but more data transparency and robust standards are needed.
Uncertainties, assumptions and omissions in LCA studies, particularly with respect to the carbon cost of transporting imported timber products, suggest that comparisons across building materials are still fraught with complexity.
If we make decisions based on what’s best for the whole lifecycle of a construction project – from strategy and set-up through to construction, operation, maintenance and demolition – then we stand a far greater chance of delivering long-term environmental outcomes that favour future generations.
Urgent attention needs to be given to developing robust LCA techniques and standards, to ensure carbon is assessed in the most effective way.
The road to a net-zero society requires urgent action from government and industry, but we need to be more holistic in our collective approach to carbon.
Written by - Guy Thompson, head of architecture, housing & sustainability at The Concrete Centre