Real estate must take a whole life cycle approach to carbon
A whole life cycle approach to buildings is needed for real estate to hit Paris Agreement targets, a new report argues.
Investment manager DWS's Decoding Carbon in Real Estate: Strategic implications of taking a whole lifecycle approach report says refurbishment of existing assets and greater use of low carbon materials will give real estate a better chance of reducing its emissions.
The report notes that embodied carbon in construction accounts for 11% of global emissions. As a consequence, refurbishment is increasingly targeted over development in some markets, such as the UK, where refurbishment is now more common than new development in the London office sector.
However, regulations and voluntary standards remain behind the curve on embodied carbon, the report says. Neither CRREM nor GRESB have integrated embodied carbon into their assessments, although both are considering this for 2024. And while green building certification regimes LEED and BREEAM both include assessments of carbon on a whole lifecycle basis, the main weighting of scoring is on minimising energy use at the operational stage.
Many nations lack databases detailing the embodied carbon of construction materials, says DWS and existing databases use different materials, assumptions, units of measurement, and standards of data verification, “making the data difficult to compare”.
The industry needs to balance embodied and operational carbon considerations, DWS says. For example, triple-glazing creates more embodied carbon than double glazing but is 40% more thermally efficient.
The picture is complicated because whole life carbon assessments can vary widely in their outcomes, depending on methodology. DWS gives the example of the proposed Marks & Spencer store redevelopment on Oxford Street, London, where the carbon lifecycle assessment included in the store’s planning submission was challenged by heritage groups on the basis that flawed assumptions were used to portray a new building as the lower carbon option.
However, a 2021 study by Arup, while demonstrating that refurbishing existing buildings is the lowest carbon option using a whole lifecycle approach, a new building constructed to the highest environmental standards is not significantly worse.