Parts of Sydney will be up to 3.7 degrees hotter by the year 2050, as urban expansion spawns ever more asphalt and concrete, new research suggests.
The ''urban heat island effect'' - the build-up of heat in built-up areas - will amplify climate change, particularly in the outer fringes of Australian cities, according to University of NSW researchers.
''If you are living near the edge of a city today, you will notice the temperature change, mainly through the minimum temperature change at night,'' said Daniel Argueso, the lead author of the study that was prepared at the Centre of Excellence for Climate System Science.
''There is also the fact that urban canyons prevent winds from moving around freely.''
Scientists have been studying the precise effects of urban heat for decades. As well as retaining heat longer than undisturbed earth or rock, artificial structures also absorb less moisture, meaning there is less cooling through evaporation. Cities also produce more heat because there is a greater density of road traffic, electrical generators and industry.
''The ground heat flux daily cycle barely changes in the surrounding areas but its amplitude increases considerably over areas of urbanisation,'' says the paper, Temperature Response to Future Urbanisation and Climate Change.
The researchers used a combination of climate models, which can estimate future temperature changes for the whole of Australia in two kilometre-wide grid squares, and urban planning data from the NSW Office of Environment and Heritage.
