There are several factors that contribute to rising temperatures globally, especially in urban spaces. The reliance on fossil fuels, combustion-engine vehicles, industry, hard building surfaces and lack of green spaces, all combine to create heat build-up within our towns and cities. Only targeted and sustained action can reduce the rising heat and help mitigate the impact of climate change.
The positive role of green infrastructure in urban environments can’t be disputed. Green walls and green facades are proven solutions that positively impact the microclimate of buildings and surroundings.
Key benefits of green infrastructure include direct alleviation of urban heat island effect through shading of heat-absorbing surfaces and via plant evapotranspiration; reduction of maximum temperatures in the vicinity by shading walls from the sun; reduced heat entry into buildings through the absorption or reflection of intense solar radiation by green vegetation; facilitation of cooling flow-through breezes – particularly with green facades where there is a gap between the facade and the building wall; and reduced need for the use of artificial cooling, which in turn can lower carbon emissions.
There is evidentiary proof that vertical greening systems have a cooling effect on buildings. While the results may vary depending on the region, local climate and the installation, the cooling effects of green walls and facades have been indicated across the board.
For instance, solar radiation reduction of up to 37% can be achieved for a wall with a single layer of leaves and 86% for five layers; energy consumption can be reduced by up to 20%; and wall surface temperatures can be reduced in a temperate zone by up to 12°C and ambient temperatures (up to 2m away) by as much as 4°C.
Why vertical green infrastructure?
Parks, gardens and other usable green spaces can contribute towards reducing heat build-up in our towns and cities. Since ground space is scarce and comes at a premium, vertical gardens such as green facades and green walls offer a solution towards greening urban environments. Green facades also benefit commercial and residential buildings through shading and heat absorption.