We have to step up to the net zero carbon challenge

As built environment professionals, we are aware that the infrastructure or buildings we design and build will, in most cases, be around for a long time. 

Looking to the future, we know that the UK only has 30 years to realise its ambition of achieving net zero carbon emissions. There really is no time to lose. The work that our sector does will be an important part of this jigsaw, but it is not a game – this is a serious challenge which needs to be overcome.

According to the UK Green Building Council (UKGBC), our built environment contributes around 40% of the UK’s total carbon footprint, so the onus is on us as professionals to ensure that our projects are sustainable and future ready.

Today, WSP has publicised the results of a high-level embodied carbon calculation we undertook on 22 Bishopsgate in July.

This followed the EN—15978 methodology and RICS Carbon Assessment and shows that London’s second tallest building has already achieved the embodied carbon reduction recommended by the London Energy Transformation Initiative (LETI) for a net zero building.

It is not sustainable to always knock down existing structures and start again – we must look to work with what we already have 

Our calculation provided 22 Bishopsgate with a total embodied carbon rating of 591 KgCO2e/m². This is 41% lower than the current ‘business as usual’ LETI benchmark and 2% lower than LETI’s target for net zero buildings.

The scope of the analysis included the substructure, superstructure, facade, MEP (Cat A Fit-out) and internal finishing elements. With MEP excluded, the rating was 489 KgCO2e/m².

Our structural engineers were able to re-use 50% of the existing three-storey basement and 100% of the existing foundations from The Pinnacle, highlighting the importance of retrofit and re-use in the context of achieving net zero.

The UKGBC says that 80% of 2050’s buildings have already been built – a staggering statistic when you think about it, and one that makes retrofitting and re-using existing building stock crucial if we’re going to decarbonise the built environment. It is not sustainable to always knock down existing structures and start again – we must look to work with what we already have more often.

Of course, the UK is lucky to have countless listed and heritage properties where the only option to bring these into the 21st century is through careful and considered retrofit. Science Gallery London at King’s College London is an excellent example of how to deliver such a transformation.

WSP’s Rethink Retrofit research, published earlier in the year, identified retrofitting existing stock through new technologies, improving energy efficiency and more effective building management systems as major priorities for the UK’s built environment profession to deliver on as an important contribution to achieving net zero by 2050.

Ultimately, each sector that contributes to the UK economy, and the everyday actions and choices of the UK population, will need to become more sustainable if we are going to achieve our collective net zero target. The challenge facing the built environment industry should not be taken lightly but the skill, knowledge and passion of its people stand us in good stead to face it head on.

Diego Padilla Philipps is an associate director for building structures at WSP and Hope Bootle is a senior sustainability engineer buildings specialist at WSP