More councils acting on urban heat island effect

Two metropolitan councils – Perth City Council and the City of Adelaide – are taking steps with data and reflective road surfaces to try mitigating urban heat effects which scientists and planners have warned will be exacerbated by increasing temperatures.

The urban heat island effect is where some places absorb and hold heat more than others, such as in buildings, large paved carparks and roads. Councils around the world are trying various methods to counter these heat islands.

Researchers say that temperatures across urban landscapes can differ by up to 10 degrees, but shading can reduce ground level temperatures by several degrees.

NSW’s Penrith City Council, which hit 48.9 degrees – the highest temperature in Australia on 4 January – has installed 120 heat sensors across the local government area to collect heat data.

Council is working with Western Sydney University to use this data to scientifically inform and influence decision making.

“At present, the only official local heat indicator we have is the Bureau of Meteorology’s weather station at Penrith Lakes, which does not accurately reflect urban heat in Penrith’s CBD,” Mayor Ross Fowler OAM said.

“We also know anecdotally there can be vast temperature differences across the region, but we lack evidence to support this.

“That’s why we need accurate new heat data from across our City to make the business case for change to industry, especially developers.”

Acting on residents’ concerns about heat island effects on Penrith’s future liveability, Council will on 18 February host a gathering of planners, developers, builders and others to explain case studies and research in action.

Western Sydney University’s Dr Sebastian Pfautsch, who leads the study for Council, said research last summer in various parts of western Sydney found that some suburbs experience more extreme heat than the Bureau of Meteorology recorded.

“By converting open, green surfaces to impermeable ones made from bitumen or concrete we reduce the capacity of water seeping into the soil and evaporating from it, whereby it cools the air.”

“Bitumen absorbs the sun’s energy and radiates it during the night, making suburbs hotter”, he added.

The City of Adelaide is part of a project to try reducing bitumen heat absorption by using three heat reflective treatments on a stretch of an inner-city street, where planting trees is not an option.

“These are also road preservation products, used to lengthen the life span of a road and therefore increase the time span between having to dig up and relay,” the City said.

The City’s encouraging pedestrians, cyclists, and others to give their feedback by 28 February about the cooling effects.

The study by Climate KIC Australia, the City, South Australian Government and engineering firm Fulton Hogan is due to be finished by the end of the summer.

“The results will be shared with local councils to help inform future cooling programs across South Australia,” the study’s website said.