France- the world’s arbiter for haute couture now takes aesthetics to a higher level: rooftops.
France has recently passed a new law that states all commercial buildings must be partially covered in either solar panels or plants. These “Green roofs” -whether featuring grasses, wildflowers or vegetable plants- majorly help to insulate buildings, hence reduce the need for both air conditioning and heating. A study led by Spanish researchers demonstrated how dense vegetation can minimize the heat entering a building via its roof by 60%, proving its effectiveness as a cooling system.
|A "Green Wall" I sighted when in Paris, at the Musée du quai|
Green roofs further help to improve air quality by absorbing toxic pollutants, as well as significantly decreasing the “heat island” effect in which urban areas are much warmer than their surroundings due to human activities. They also help with storm water management- the water is stored by the substrate (underlying substance or layer), then is absorbed by plants, thus returned to the atmosphere via evapotranspiration.
In densely developed cities, they additionally provide a place for urban wildlife, such as for birds to nest, and people to grow food. As space is limited within bustling cities, Green Roofs also open new recreational areas for community gardens.
However they do have their disadvantages- Green roofs are not cheap to install and maintain, and their price and complexity may discourage homeowners and developers. Nevertheless a 2008 study by the University of Michigan showed that their benefits do outweigh the additional initial investment.
I think Green Roofs are a very positive step forward towards more eco-friendly cities. For there are so many unused rooftops in cities today that could potentially instantaneously cover their own power needs, as solar photovoltaics can be seamlessly integrated within an urban setting.