The environmental benefits of green/living roofs within an urban setting are widely recognised. The Greater London Authority’s Climate Change Adaptability Teams modelling of the urban heat island effect in London establishes areas where action will be required in the future to adapt to climate change.

It is anticipated that green roofs will be a pragmatic and often the only means of adapting the urban fabric especially in central London, to climate change.

A green roof will provide high water retention thus reducing and delaying run off during times of heavy and prolonged precipitation. In summer green roofs can retain 70-80% of rainfall and in winter between 25-40%. Urban environments have large areas of hard reflective surfaces that absorb solar radiation and reflect this heat back into the atmosphere producing temperature differences with surrounding rural areas.
The vegetation on a green roof can absorb heat thus reducing this effect. As well as providing a habitat for insects and other wildlife a green roof contributes to the reduction of a number of polluting air particles and compounds not only through the plants themselves, but also by deposition in the growing medium. A green
roof system is recognised as providing good thermal performance through its mass and by cooling and humidifying the surrounding air. It also protects the building fabric from mechanical damage and ultra-violet radiation, thus extending a roofs life.