1 June 2023: As a developer, my instinct is to approach this subject by a set of principles, notwithstanding the dense technical work behind the methods and strategies for carbon reduction in the built environment today. If asked “do we need to build any new buildings?” my response is a resounding yes. We need to and we must.

It’s an emotive question, and intentionally so; but it is impossible to envisage cities in the future without incorporating new buildings. Populations and economies are growing and that simply cannot be contained within existing stock. The built environment should also reflect a society’s past, present and future, while aligning with its economic, social and cultural activities. To maintain its position as a global centre of financial services, technology and innovation, including the burgeoning life sciences sector, today’s London needs to evolve to keep attracting talent and investment, as it always has done. It is not a city fixed in time.

While we now have much more sophisticated processes to assess the carbon cost of buildings and ways of adapting and reusing existing ones, the idea of retrofit-only does not work. It would inhibit our progress as an industry towards resolving the massive issues around humanity’s environmental impact.

Without the option for new development, real estate would be one of the only major industries disallowed from producing anything wholly new. Compare this to car manufacturing, where the invention and design of new technology is integral to moving away from carbon. There is no expectation, or technological method, to retrofit all existing vehicles in this endeavour. The same principle applies to development: new buildings facilitate the development of smarter technologies, materials and methods – such as using lightweight concrete, the mass use of timber in commercial construction, or building in infrastructure that allows for adaptation in the future.

Retrofit should be the first consideration, but can only be applied on a case-by-case basis. There are many great buildings where reuse does work. Take Sellar’s redevelopment of Grand Union House in Camden, which will transform the underutilised office and industrial property into a mixed-use destination that will be a benchmark for sustainable, low-carbon development in London. Key to achieving this is the adaptive reuse of the existing building, retaining its concrete structure to minimise waste and embodied CO2. However, there are many buildings where reuse either will not deliver what occupiers need or the building cannot be adapted for modern technology. Refurbishing something that customers do not actually want is a waste of carbon in itself. In such cases, new development becomes the most economic and environmentally viable option, particularly when considered over the whole lifetime of a building.

This is where another firm principle must be applied: even if a building meets all modern environmental standards, it is not truly sustainable if it is not used intensively. The least sustainable building is an empty one, whereas an efficient building is one that people want to use. This is why it is important to have spaces that suit modern requirements and one of the reasons many companies are paying prices for real estate that encourages use and supports in-person collaboration.