When you think of a “green building”, you might picture an aesthetically dubious structure with sustainability on its side.

When you think of a “green building”, you might picture an aesthetically dubious structure with sustainability on its side. Soon, you could be thinking of something like the behemoth pictured – green roofing, which helps to reduce the “heat island effect” in towns and cities.

Green roofs save energy by replacing air conditioning plant with live plants – the surprisingly vegetative lamb and elephant ears, to be precise – which absorb less heat than concrete and can also cool the air via the process of evapotranspiration. The roofs also reduce the risk of flooding by absorbing rainwater.

Tijana Blanusa, a Royal Horticultural Society researcher based at the University of Reading, compared a variety of plants to see if differences in leaf shape and structure would have varying effects on the temperature of the air above them, and discovered over a two-year period that lamb’s ear has the coolest leaves.

Says Blanusa: ‘There is a growing movement in terms of research and environmentalists who are progressing this idea, and Britain could be next in line after Germany to take it up.’

There was certainly a lot of corporate interest at the World Green Roof Congress, which brings together leading green roof experts from across the world and provides a platform for communicating the latest green roofing case studies, research and policy initiatives.

From a CSR point of view, green roofs are a very visible sign of a company’s eco-friendly credentials, so it may not be long before our workplaces are adorned with this most natural means of air conditioning.