Thermal images released in January 2017 show that the urban heat island effect is taking its toll on Australia’s major urban areas. Melbourne, Brisbane, Perth, and Sydney, four of the country’s sunniest and most beautiful cities, have suffered several heatwaves in the past few years.
Urban Heat Island (UHI) is just one of the many effects of urban sprawl – and it is purely manmade. While global warming is a major factor, UHI is the accumulated effects of a city’s distinct physical features, lifestyle, and local greenhouse emissions. The hot winds blowing in from the country’s vast deserts don’t help either.
In fact, researchers at UNSW claim that these heat events are a much bigger problem than bushfires, earthquakes and other major calamities combined. To tackle these problems, regional governments work together to increase resiliency in their cities.
Researchers have found that darker and denser pavement materials tend to absorb more heat than brighter-coloured and more porous ones. One approach is to replace inner city roads with green roads to reduce heat absorption. In sunny areas, pavement watering may also help bring down UHIs. With porous pavements, water will seep into the surface much quicker – fast enough to prevent the next heatwave.
Another solution is to plant more tree canopies and build green roofs and walls throughout the city to offset the effects of anthropogenic heat. Lining roads and pavements with trees can significantly cut down temperatures and increase pedestrian comfort when heatwaves occur, experts say.
Tall, glass buildings play a major role in heat events. They tend to create glare that has negative outcomes on neighbouring buildings and public spaces. The glare can cause plastic car parts to melt and inconvenience pedestrians. It can also increase the temperature of roads and pavements.
A better solution is to paint facades and sunshade aluminium screens with brighter colours so the sun’s radiation is reflected back out rather than absorbed by the building. This can also result in reduced air conditioning needs during hot periods; hence, less energy consumption and lower greenhouse emissions.
Sydney and Melbourne have launched several efforts to address future UHIs. By 2030, they plan to increase tree canopies by 50%, paint buildings with brighter colours and build more greenery on roofs and inner city structures. Now that threats of climate change are unfolding before their eyes, Australia is determined to build a cooler future for its urban populace.