Urbanisation is accelerating around the world and will continue until over 7 billion people live in cities by the end of the century. How, under such conditions, can we reduce energy consumption and ambient noise pollution, improve air quality and people’s well-being?
“In ever denser cities the space for green infrastructure, such as parks and green recreational spots, is being depleted. What is often considered as “green architectural decoration” is, however, an important element in our built environment and should not be underestimated.” This is according to the minds of Arup, and we tend to agree.
Retrofitting cityscapes with vegetation improves the health and well-being of urban citizens. Green building envelopes can help to reduce the urban up-heating (heat island effects), filter fine dust on the streets and reduce noise levels.
Buildings covered in a carpet of vegetation and greenery are sprouting up all over the world – look at Aurecon East by MaC Architects in Century City, Cape Town; One Central Park in Sydney; or Bosco Verticale in Milan.
Measurements were taken in five cities – Berlin, Hong Kong, Melbourne, London, and Los Angeles – to see what impact extra greenery could have.
First of all, plants pull carbon dioxide out of the air and convert it into oxygen. Green coverings also significantly reduce other pollutants in the air, including soot and dust. While a couple of skyscrapers might not fix city-wide smog problems, the Arup study found that pollutants in the air between two plant-covered buildings could be reduced by as much as 20 percent.
Green buildings also cool down our cities by blocking the ‘urban heat island effect’, where buildings and roads radiate heat. Arup modelled what densely populated cities would be like with more green facades, and found that in high-rise cities such as Hong Kong, green buildings could lead to temperature reductions of up to 10 degrees Celsius.
With our planet being robbed of its rainforests and getting increasingly warmer, we could really use some vegetation in our cities to counter these effects.
Another positive impact that’s not immediately obvious is better drainage – with plants and shrubs there to soak up rainwater and delay the time it takes water to get from sky to ground, the damaging effects of flash floods aren’t as severe as well as reducing the pressure on city infrastructure.
Other benefits are better well-being for office workers who can enjoy more nature (and cleaner air), plus a more diverse urban ecology, allowing insects, birdlife and plants to flourish.
The incorporation of green infrastructure will help to reduce energy consumption, improve air quality and people’s wellbeing. As Architects, we are in the driving-seat in terms of designing our cities and as such, it is our responsibility to spearhead such initiatives. The problem of overpopulation and over-densified cities is our opportunity to rethink how the liveability of our cities can be improved upon.
Read or download the full Arup Cities Alive report here.
Arup Cities Alive report – Sept 2016
ScienceAlert – David Nield – 7 Oct 2016