100 Liverpool Street – reusing existing structure (left) and adding new (right).

As part of our 2030 strategy, British Land has committed to reduce embodied carbon in our office developments by 50% to below 500kg CO₂e per m² by 2030. Drawing on insights from studies we’ve commissioned into embodied carbon over a decade, we’re raising the profile of carbon as a performance metric for our design partners. This is essential not only for the sustainable future of our planet, but also of our business, as our customers and investors are already demanding low carbon places.

From a climate perspective, to stay below 1.5º warming, the actions we all take in the next 10 to 20 years are going to have a bigger impact over the coming century than what happens in the years that follow. So, we must do everything in our power now to get carbon out of our buildings – or more accurately, stop it being there in the first place.

Embodied carbon linked to the extraction, manufacture and transport of materials makes up a big part of the whole life footprint of a building. We’ve been on a journey to cut embodied carbon on our developments since 2009, when we commissioned one of the first studies in the UK at Ropemaker Place. We’ve followed that up with studies on other projects, often sharing findings to improve industry understanding and drive progress.

We now have a large bank of data and are building a picture of what good looks like, comparing different projects. I’m excited about the opportunities that this is highlighting, as we see which systems, structural designs and project types return the lowest embodied carbon. Ultimately, we’ll be giving carbon the same prominence in design as other more familiar performance metrics such as cost, durability and flexibility.

Breaking new ground

The climate challenge is huge but it’s leading to all kinds of new conversations with our supply chain partners – including architects, engineers and contractors – around materials, construction techniques and carbon accounting. Together, we’re breaking new ground.

At 100 Liverpool Street, we worked with Hopkins Architects, AKT II, Greengage and Sir Robert McAlpine to retain and reuse as much as possible – including 32% of the steel frame – saving 3,435 tonnes of carbon vs new, enough to offset energy consumption in around 1,000 homes for a year. At least 49% of all concrete used in the project was retained and reused – saving 4,086 tonnes of carbon vs new. Where new materials were needed, lower carbon choices included 51% secondary aggregates (recycled waste aggregates rather than virgin) used overall in the concrete and 44% cement replacement (GGBS) in concrete mixes. We’ve quantified the impact using the RICS framework for whole life carbon – independently verified results show an embodied carbon intensity of 395kg CO₂e per m² for A1-5.

We’re deploying what we’re learning on other projects as quickly as possible, including 1FA, 135 Broadgate and 1 Triton Square. Read a blog by Arup on 1 Triton Square here.

Accounting for carbon

We’ve appointed Simon Sturgis of Targeting Zero to review four of our embodied carbon studies, looking at them collectively to draw lessons from ten years of project data, in the context of today’s knowledge and tools. We have a long association with Simon, who is a low carbon expert.

Here are some of the areas we’re exploring together:

• Consistency – there are inconsistencies in how different organisations assess carbon, using methodologies such as One Click LCA and the BREEAM EPD Verification Scheme. The RICS framework has given the UK a robust methodology to measure whole life carbon. We’re using this to improve consistency, so we can compare apples with apples to make the best decisions and evaluate performance.
• Leadership – Simon speaks powerfully about the importance of architects taking on the role of carbon lead for their projects, coordinating with engineers and other parties. We’ve taken steps towards this in our latest Sustainability Brief, which includes a challenging sustainability statement that will be part of every project from the outset. This is the seventh version of our Brief since we first introduced it in 2004, with each update pushing new boundaries.
• Whole life – we began with embodied carbon in construction, as that offers the biggest savings opportunities. The next part of the whole life puzzle is embodied carbon during the operational phase. We’re starting conversations with facilities teams about this, so before replacing a chiller, they weigh up the embodied carbon impact of extending its life versus operational savings from new kit. This will build on our energy efficiency programme, which has contributed to a 73% cut in operational carbon intensity since 2009. There’s always more to do!
• Targets – since we set our five-year target to cut embodied carbon on our major developments by 15% per m² by 2020, a lot has changed, including the publication of the RICS framework. Our embodied carbon target has driven our supply chain partners both in accounting for carbon and in reducing it, but we’re now going beyond this, looking at whole life carbon – from design, through construction, to operation and deconstruction. We launched our new carbon targets in May, as part of our 2030 strategy.

Find out more about how we are working to transform our portfolio to net zero carbon by 2030

British Land supports the Architects’ Journal’s RetroFirst campaign, which calls for action to slash embodied carbon emissions in construction by encouraging greater use of retrofit and refurbishment.