The green lease has steadily become more and more mainstream over the past decade. Corporate occupiers now regularly require that buildings meet their own sustainability, environmental and wellness standards and that binding commitments are written into the their leases. However, most of these environmental and sustainability provisions only focus on energy consumption during the term of their lease and ignore the initial embodied energy of the building. 

Embodied energy is the energy contained in the building's structural materials plus what was consumed during the construction process. When considering a building's environmental and sustainability credentials, to ignore the embodied energy is the equivalent of considering the rent, but not taking into account the rent-free periods.

Tim Snelson of Arup, writing for Domus magazine, has calculated that the average skyscraper will have double the carbon footprint of a 10 storey building of equivalent square footage. A tall building is more structurally challenging to build, requiring deeper foundations - especially when built on London clay - and greater rigidity for stability, to prevent sway. All of this requires extra materials, which add to the building's embodied energy. 

When skyscrapers are sold on their environmental and sustainability credentials, it is incumbent on occupiers to seriously question these assertions, if they are themselves to have their own environmental and sustainability credentials taken seriously. 

With sustainability moving up the agenda, could we start to see our skyline coming down?