A team of UNSW researchers is trying to find ways to cool our concrete jungles down before they eventually become uninhabitable. 

Nowhere is this more important than in areas such as western Sydney, where devoid of the ocean breezes that usually cool the coastal fringe, the city’s western half suffers from the urban heat island effect, thanks to building materials absorbing more of the sun’s energy, waste heat from car engines and air conditioners all conspiring to heat up the temperature. 

And this is not just a Sydney problem – over 500 cities across the globe are currently dealing with this problem.

“Urban heat islands are the most documented phenomenon of climate change,” says UNSW Built Environment’s Professor of High Performance Architecture, Mat Santamouris, who has spent the past 15 years mapping urban heat islands in 200 cities, including a collaboration with the European Union that led to the first complete study of urban heat islands in European cities.

“If we can’t find a way to make our cities cooler, they will eventually become uninhabitable,” he says. “It's hard to remember that kind of heat when we’re in the middle of winter, but last summer the temperature in Penrith was above 40 degrees celsius for about 20 days, reaching even 46 degrees celsius.”

A significant portion of this research involves finding heat-mitigation technologies to help cool our cities such as the use of shading, cool roofs and new-generation, pavements that absorb less solar radiation and green roofs.

“The goal now is to develop heat mitigation solutions capable of reducing urban temperatures by five degrees, and in the case of western Sydney, it needs to be by seven degrees,” he says.

“This is the first large-scale project in the world to involve people in the understanding of heat mitigation.”

“Urban overheating is perhaps among the more severe climatic phenomena that humanity faces, but I’m confident that in a three- to five-year period, we will be able to decrease peak ambient temperatures by up to four or five degrees celsius,” Santamouris says.